ADCT ADC Therapeutics SA

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ADC Therapeutics SA (the “Company” or “ADCT”) was incorporated on June 6, 2011 under the laws of Switzerland. The registered office of the Company is located at Route de la Corniche 3B, 1066 Epalinges, Switzerland. The Company controls three wholly-owned subsidiaries: ADC Therapeutics America, Inc. (“ADCT America”), which was incorporated in Delaware, USA on December 10, 2014, ADC Therapeutics (UK) Ltd (“ADCT UK”), which was incorporated in England on December 12, 2014 and ADC Therapeutics (NL) B.V. which was incorporated in the Netherlands on February 25, 2022. The Company and its three subsidiaries form the ADCT Group (the “Group”).

The Group is focused on the development and commercialization of antibody drug conjugates (“ADCs”), including research, development, human clinical trials, regulatory approval and commercialization. On April 23, 2021, the U.S. Food and Drug Administration (“FDA”) approved ZYNLONTA for the treatment of relapsed or refractory diffuse large B-cell lymphoma (“DLBCL”) and the Company commenced recognizing revenue upon the sale of ZYNLONTA during the second quarter of 2021. ADCs are drug constructs which combine monoclonal antibodies specific to particular types of cells with cytotoxic molecules or warheads which seek to kill cancer cells to which the ADC attaches. ADCs have extensive potential therapeutic applications in cancer.

These unaudited condensed consolidated interim financial statements were authorized for issue on August 8, 2023.

Going concern basis

ADCT is a commercial-stage company developing innovative therapeutics. The Group is exposed to all risks inherent in establishing and developing its business, including the substantial uncertainty that current projects will succeed. The Group’s success may also depend on its ability to:

•establish and maintain a strong patent position and protection;

•develop, gain regulatory approval and commercialize drug products;

•enter into collaborations with partners in the pharmaceutical industry;

•acquire and retain key personnel; and

•acquire additional funding to support its operations.

Since its incorporation, the Group has primarily funded its growth through capital increases and additional funds provided by research collaborations, license agreements, the issuance of the Company’s common shares, the issuance of convertible loans, the issuance of term loans and proceeds from a royalty purchase agreement. The Group does not have recourse to bank loans. As a result, the Group is not exposed to liquidity risk through requests for early repayment of loans, other than, pursuant to the senior secured term loan facility, it must maintain a balance of at least USD 60.0 million in cash and cash equivalents plus any accounts payable that are greater than ninety days old at the end of each quarter.

As of June 30, 2023, the Group’s cash and cash equivalents amounted to USD 347.5 million (December 31, 2022: USD 326.4 million).

Management believes that the Group has sufficient resources to meet its financial obligations for at least the next 12 months from the date of issuance of these unaudited condensed consolidated interim financial statements and, as a result, is presenting these unaudited condensed consolidated interim financial statements of the Group on a going concern basis.

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Statement of Compliance

These unaudited condensed consolidated interim financial statements as of and for the three and six months ended June 30, 2023 have been prepared in accordance with International Accounting Standard 34 Interim Financial Reporting (“IAS 34”) and should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2022.

Functional and reporting currency

These unaudited condensed consolidated interim financial statements are presented in United States Dollars (“USD” or “$”), which is the Company’s functional currency and the Group’s reporting currency.

A subsidiary of the Company, ADCT UK, has a functional currency of the British Pound (“GBP”). The following exchange rates have been used for the translation of the financial statements of ADCT UK:

			Six Months Ended June 30,
			2023						2022
USD / GBP
Closing rate, GBP 1			1.26627						1.21470
Weighted average exchange rate, GBP 1			1.24535						1.20080

Basis of Consolidation

The unaudited condensed consolidated interim financial statements incorporate the financial statements of the Company and entities controlled by the Company which are the same as those contained in the audited consolidated financial statements as of and for the year ended December 31, 2022.

Use of estimates and judgements

The preparation of the unaudited condensed consolidated interim financial statements in conformity with IAS 34 requires management to make judgements, estimates and assumptions that affect the application of accounting policies and the reported amounts of assets and liabilities, income and expense. Actual results may differ from these estimates.

Estimates are based on management’s knowledge of current events and actions that the Company may undertake in the future. Estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the period in which the estimate is revised if the revision affects only that period, or in the period of the revision and future periods if the revision affects both current and future periods.

In preparing these unaudited condensed consolidated interim financial statements, the significant judgements made by management in applying the Group’s accounting policies and the key sources of estimation uncertainty included those that applied to the consolidated financial statements for the year ended December 31, 2022. There have been no material changes to the use of estimates and judgements other than those described in note 3, "Significant accounting policies."

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The accounting policies applied by the Company in these unaudited condensed consolidated interim financial statements are the same as those applied by the Company in its audited consolidated financial statements as of and for the year ended December 31, 2022 and have been applied consistently to all periods presented in these unaudited condensed consolidated interim financial statements, except for the following:

Revenue Recognition

Product Revenue

The Company generates revenue from sales of ZYNLONTA in the U.S. for the treatment of relapsed or refractory DLBCL, which was approved by the FDA on April 23, 2021 and launched shortly thereafter. Revenue is recognized when control is transferred to the customer at the net selling price, which includes reductions for gross-to-net (“GTN”) sales adjustments such as government rebates, chargebacks, distributor service fees, other rebates and administrative fees, sales returns and allowances and sales discounts.

On November 15, 2021, the Infrastructure Investment and Jobs Act was enacted, which added a requirement for manufacturers of certain single-source drugs (including biologics and biosimilars) separately paid for under Medicare Part B for at least 18 months and marketed in single-dose containers or packages (known as refundable single-dose container or single-use package drugs) to provide annual refunds if those portions of the dispensed drug that are unused and discarded exceed an applicable percentage defined by statute or regulation. The Centers for Medicare & Medicaid Services (the “CMS”) finalized regulations to implement this section on November 18, 2022, and the provision went into effect on January 1, 2023.

The Company has accounted for this annual refund (“discarded drug rebate”) as a GTN sales adjustment beginning in the first quarter of 2023. The discarded drug rebate will involve significant estimates and judgment after considering factors including legal interpretations of applicable laws and regulations, historical experience with discarded volumes and processing time lags.

The Company uses information from external sources to identify the Company’s discarded volumes and estimate the discarded drug rebate. The Company’s estimates are subject to inherent limitations of estimates that rely on third-party information and reflect other limitations including lags between the date as of which third-party information is generated and the date on which the Company receives third-party information. Estimates for the discarded drug rebate are being assessed each period and adjusted as required to revise information or actual experience.

New and amended IFRS standards

There are no new IFRS standards, amendments to standards or interpretations that are mandatory for the financial year beginning on January 1, 2023, that are relevant to the Group. New standards, amendments to standards and interpretations that are not yet effective, which have been deemed by the Group as currently not relevant, are not listed here.

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4.1Financial risk factors

The Group’s activities are exposed to a variety of financial risks: market risk (including changes in the Company’s share price, exposure to fluctuation in currency exchange rates and exposure to interest rate movements), credit risk and liquidity risk.

The unaudited condensed consolidated interim financial statements do not include all financial risk management information and disclosures required in the annual financial statements, and should be read in conjunction with the Group’s consolidated financial statements as of December 31, 2022. In relation to the royalty purchase agreement with entities managed by Healthcare Royalty Management, LLC ("HCR"), the Company is obligated to pay interest in the form of royalties in connection with certain net sales and licensing revenue. As the effective interest rate ("EIR") on the deferred royalty obligation does not depend on market performance, the exposure to interest rate and market risk is deemed low. See note 17, “Deferred royalty obligation” for further information. In regards to the senior secured term loans, the interest rate is variable and dependent upon market factors. The Company will update the EIR at the end of each reporting period for changes in the rate. See note 13, "Senior secured term loan facility and warrants" for further information. A hypothetical 100 basis point increase (decrease) in the interest rate as of June 30, 2023 would have increased (decreased) the effective interest expense associated with the Company's senior secured term loan facility by KUSD 910 and (KUSD 910). There have been no other material changes in financial risk management since December 31, 2022.

4.2Fair value estimation

As of June 30, 2023, the carrying amount is a reasonable approximation of fair value for the following financial assets and liabilities:

•Cash and cash equivalents

•Trade accounts receivable; and

•Trade accounts payable

In the six months ended June 30, 2023, there were no significant changes in the business or economic circumstances that affected the fair value of the Group’s financial assets and financial liabilities.

Fair values must be estimated at the end of each reporting period with regard to the senior secured term loan warrant obligation and the Deerfield warrants. The approach to valuation follows the grant date fair value principle, and the key input factors are described for the senior secured term loan facility warrant obligation in note 13, "Senior secured term loan facility and warrants" and for the Deerfield warrants in note 15, "Deerfield warrants." Commonly accepted pricing models (Black-Scholes) have been used to calculate the fair values. The valuation of the senior secured term loan facility warrant obligation and Deerfield warrants are classified as pertaining to Level 2 of the valuation hierarchy. The convertible loan derivatives previously were classified as pertaining to Level 3 of the valuation hierarchy and were extinguished on August 15, 2022. See note 14, "Convertible loans" for further information. The Company no longer has any inputs pertaining to level 3 of the valuation hierarchy set out below.

The different levels of the valuation hierarchy have been defined as follows:

(a)Level 1: quoted prices (unadjusted) in active markets for identical assets or liabilities;

(b)Level 2: inputs other than quoted prices that are observable for the asset or liability, either directly (for example, as prices) or indirectly (for example, derived from prices);

(c)Level 3: inputs for the asset or liability that are not based on observable market data.

There were no transfers between the respective levels during the period.

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The table below provides a disaggregation of revenues by type of service and customer location for the three and six months ended June 30, 2023 and June 30, 2022.

						Three months ended June 30,												Six months ended June 30,
(in KUSD)						2023						2022						2023						2022
Types of goods and services
Product revenue, net						19,197						17,291						38,150						33,789
License revenues						—						—						—						30,000
Royalties						86						—						125						—
Total revenue						19,283						17,291						38,275						63,789
Customer Location
U.S.						19,197						17,291						38,150						33,789
EMEA(1)						86						—						125						—
Japan						—						—						—						30,000
Total revenue						19,283						17,291						38,275						63,789

(1) Europe, the Middle East and Africa

Product revenue, net

Product revenues, net from sales of ZYNLONTA were KUSD 19,197 and KUSD 38,150 for the three and six months ended June 30, 2023. Product revenues, net from the sales of ZYNLONTA were KUSD 17,291 and KUSD 33,789 for the three and six months ended June 30, 2022, respectively. The Company records its best estimate of GTN sales adjustments to which customers are likely to be entitled.

The table below provides a rollforward of the Company’s accruals related to the GTN sales adjustments for the three and six months ended June 30, 2023 and June 30, 2022.

						Three months ended June 30,												Six months ended June 30,
(in KUSD)						2023						2022						2023						2022
Beginning balance						4,362						4,126						3,746						2,590
GTN sales adjustments for current period sales						5,783						3,206						11,399						6,697
GTN sales adjustments for prior period sales						(229)						87						(877)						(105)
Credits, payments and reclassifications to Accounts payable						(4,182)						(3,955)						(8,534)						(5,718)
Ending balance as of June 30,						5,734						3,464						5,734						3,464

The table below provides the classification of the accruals related to the GTN sales adjustment included in the Company’s unaudited condensed consolidated interim balance sheet as of June 30, 2023 and December 31, 2022.

(in KUSD)						As of June 30, 2023						As of December 31, 2022
Accounts receivable, net						1,677						2,151
Other current liabilities						4,057						1,595
						5,734						3,746

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License revenues and royalties

On January 18, 2022, the Company entered into an exclusive license agreement with MTPC for the development and commercialization of ZYNLONTA for all hematologic and solid tumor indications in Japan. Under the terms of the agreement, the Company received an upfront payment of USD 30 million and may receive up to an additional USD 205 million in milestones if certain development and commercial events are achieved. The Company will also be entitled to receive royalties ranging in percentage from the high teens to the low twenties based on net sales of ZYNLONTA in Japan. MTPC will conduct clinical studies of ZYNLONTA in Japan and will have the right to participate in any global clinical studies by bearing a portion of the study costs. In addition, the Company will supply ZYNLONTA to MTPC for its drug development and commercialization under a supply agreement.

On July 8, 2022, the Company entered into exclusive license agreement with Sobi for the development and commercialization of ZYNLONTA for all hematologic and solid tumor indications outside of the U.S., greater China, Singapore and Japan. Under the terms of the agreement, the Company received an upfront payment of USD 55 million and is eligible to receive up to USD 382.5 million in regulatory and net sales-based milestones, of which USD 50 million in license revenue was recognized in December 2022 upon approval of a Marketing Authorisation Application by the European Commission for ZYNLONTA in third-line DLBCL and received in the first quarter of 2023. The Company will also receive royalties ranging in percentage from the mid-teens to the mid-twenties based on net sales of the product in Sobi’s licensed territories, subject to certain adjustments. The Company recognized KUSD 125 of revenue attributable to royalties in the Sobi licensed territories during the six months ended June 30, 2023.

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The following table provides the unaudited condensed consolidated interim statement of operations classification of the Company's total operating expense:

(in KUSD)			Three months ended June 30,												Six months ended June 30,
			2023						2022						2023						2022
Cost of product sales			1,319						2,266						1,909						2,795
R&D
External costs (1)			17,947						30,175						39,601						59,343
Employee expenses (2)			13,997						18,362						31,823						38,146
R&D expense			31,944						48,537						71,424						97,489
S&M
External costs (1)			8,329						9,259						15,689						18,170
Employee expenses (2)			6,127						8,400						14,118						17,859
S&M expense			14,456						17,659						29,807						36,029
G&A
External costs (1)			4,881						5,880						9,419						13,519
Employee expenses (2)			6,472						12,360						17,077						23,732
G&A expense			11,353						18,240						26,496						37,251
Total operating expense			59,072						86,702						129,636						173,564

(1) Includes depreciation expense

(2) Includes share-based compensation expense

The decrease in Cost of product sales for the three and six months ended June 30, 2023, was primarily driven by higher impairment charges for the three and six months ended June 30, 2022 related to the manufacturing of batches that did not meet the Company's specifications.

R&D external costs decreased for the three and six months ended June 30, 2023 as a result of the completion of the phase 2 study in 2022 for Camidanlumab Tesirine (Cami) and our decision to pause the program while we evaluated FDA feedback, continue to assess a potential regulatory pathway and seek a partner to continue developing this program. The Company also had higher cost sharing with our partners, lower clinical trial costs for LOTIS 3, LOTIS 6 and LOTIS 7, as well as lower professional fees related to ZYNLONTA, partially offset by higher clinical trial expenses for LOTIS 5 and LOTIS 9 and in ADCT-212 the Company incurred lower manufacturing expenses related to IND-enabling work. The decrease in external costs was partially offset by an increase in clinical trial costs for ADCT-901 and expenses related to the Company's preclinical product candidates and research pipeline. Employee expense decreased for the three and six months ended June 30, 2023 primarily due to lower share-based compensation expense driven by fluctuations in our share price, voluntary terminations and the workforce reduction announced and put into effect during the second quarter of 2023.

The decrease in S&M expenses for the three and six months ended June 30, 2023 was primarily due to lower share-based compensation expense due to the fluctuations in the Company's share price, voluntary terminations and the commercial re-alignment announced and put into effect during the second quarter of 2023, as well as lower spend on marketing, analytics and expenses, including those expenses in the European Union relating to the commercial launch of ZYNLONTA.

The decrease in G&A expenses for the three and six months ended June 30, 2023 was attributable to lower share-based compensation expense due to fluctuations in the Company's share price, transition of a board member, voluntary terminations and the workforce reduction announced and put into effect during the second quarter of 2023, as well as lower external costs related to insurance and IT, partially offset with higher professional fees. The decrease in G&A expenses for the six months ended June 30, 2023 was also attributable to professional fees associated with the license agreement entered into with MTPC recognized during the six months ended June 30, 2022, partially offset by higher wages and benefits.

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The components of financial income for the three and six months ended June 30, 2023 and June 30, 2022 are as follows:

												Three months ended June 30,												Six months ended June 30,
(in KUSD)						Note						2023						2022						2023						2022
Interest income												2,372						16						4,547						36
Cumulative catch-up adjustment, deferred royalty obligation						17						—						—						—						18,288
Financial income												2,372						16						4,547						18,324

The components of financial expense for the three and six months ended June 30, 2023 and June 30, 2022 are as follows:

												Three months ended June 30,												Six months ended June 30,
(in KUSD)						Note						2023						2022						2023						2022
Cumulative catch-up adjustment, deferred royalty obligation						17						5,417						—						5,288						—
Deferred royalty obligation interest expense						17						5,829						5,545						11,575						11,687
Effective interest expense on senior secured term loan facility						13						4,480						—						9,020						—
Effective interest expense on convertible loans						14						—						3,126						—						6,148
Interest expense on leasing and other						12						131						130						262						183
Financial expense												15,857						8,801						26,145						18,018

The components of non-operating (expense) income for the three and six months ended June 30, 2023 and June 30, 2022 are as follows:

												Three months ended June 30,												Six months ended June 30,
(in KUSD)						Note						2023						2022						2023						2022
Convertible loans, derivatives, change in fair value income						14						—						14,455						—						30,310
Deerfield warrant obligation, change in fair value income						15						20						—						636						—
Senior secured term loan facility, warrants, change in fair value (expense) income						13						(39)						—						617						—
Share of results with joint venture						11						(767)						(1,917)						(2,130)						(4,419)
Exchange differences gain (loss)												18						223						(34)						304
R&D tax credit												315						114						455						122
Non-operating (expense) income												(453)						12,875						(456)						26,317

Convertible loans, derivatives, change in fair value income

Changes in derivative fair values are explained in note 14, “Convertible loans.” Pursuant to the Facility Agreement with Deerfield, the Company drew down the Deerfield First Tranche of the convertible loans amounting to USD 65.0 million on May 19, 2020. Additionally, in connection with the FDA approval of ZYNLONTA, the Company drew down the Deerfield Second Tranche of convertible loans amounting to USD 50.0 million on May 17, 2021. On August 15, 2022, pursuant to the exchange agreement with Deerfield, Deerfield exchanged USD 115.0 million aggregate principal amount of the

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Company's senior secured convertible notes for warrants to purchase an aggregate of 4,412,840 common shares, an aggregate of 2,390,297 common shares and cash equal to USD 117.3 million.

Deerfield warrant obligation, change in fair value income

Pursuant to an exchange agreement with Deerfield entered into on August 15, 2022, the Company issued warrants to purchase an aggregate of 4,412,840 common shares. The Deerfield warrant obligation has been recorded at its initial fair value and is remeasured to fair value at the end of each reporting period. Changes in fair value of the Deerfield warrant obligation are explained in note 15, "Deerfield warrants."

Senior secured term loan facility, warrants, change in fair value (expense) income

The Company has accounted for the First Tranche of the senior secured term loan and warrants as one hybrid financial instrument, with the USD 120.0 million proceeds separated into two components: a warrant obligation and a loan. The warrant obligation has been recorded at its initial fair value and is remeasured to fair value at the end of each reporting period. Changes in fair value of the warrant obligation are explained in note 13, "Senior secured term loan facility and warrants."

Share of results with joint venture

In connection with the formation of Overland ADCT BioPharma in December 2020, the Company recorded its proportionate share of Overland ADCT BioPharma’s comprehensive loss. See note 11, “Interest in joint venture.”

Exchange differences gain (loss)

Also included in non-operating (expense) income are favorable or unfavorable Exchange differences. The Company is exposed to foreign exchange risk arising from various currency exposures, primarily with respect to British pounds, Euros and Swiss francs. Exchange differences represent gain or (loss) based on favorable or unfavorable changes in foreign currencies.

R&D tax credit

The Company recognizes as income (expense) amounts received and receivable by its subsidiary, ADCT UK, under the United Kingdom’s R&D Expenditure Credit scheme (“UK R&D Credit Scheme”). The grants represent 20% of eligible expenditures for the three months ended June 30, 2023 and represent 13% of eligible expenditures for the three months ended March 31, 2023. The grants represent 12% of eligible expenditures for the three and six months ended June 30, 2022. The claims are payable through the tax system, as a refund of corporation tax or of other taxes, including income tax and social security payments deducted at source from qualifying (research) employees’ payroll and VAT. The relevant amounts have been therefore presented net in the balance sheet. As the credit is independent of ADCT UK’s taxable profit, is clearly designed to incentivize companies to invest in R&D activities and is itself taxable income, the Group has recognized the income as government grants within non-operating (expense) income and not as a credit to income tax expense.

Inventory as of June 30, 2023 and December 31, 2022 consisted of the following:

(in KUSD)						As of June 30, 2023						As of December 31, 2022
Work in process						19,015						18,165
Finished goods						413						399
Total inventory						19,428						18,564

Impairment charges of KUSD 726 and KUSD 872 were recognized and charged to cost of product sales in the unaudited condensed consolidated interim statement of operations during the three and six months ended June 30, 2023, respectively.

For the three and six months ended June 30, 2022, the Company designated certain capitalized pre-approval ZYNLONTA inventory for R&D use and recorded a charge to R&D expenses, which was partially offset by a reversal of previously

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During the six months ended June 30, 2023, the Company did not capitalize any license fees as intangible assets. During the six months ended June 30, 2022, the Company capitalized the following milestone payments as intangible assets:

•An amount of KUSD 500 paid upon the dosing of a specific number of patients in the first in-human clinical study related to an antibody the Company acquired from a third party to be used in research, development, manufacturing and commercialization. The amount was capitalized as an indefinite-lived intangible asset; and

•    An amount of KUSD 195 paid upon the successful completion of in-vivo efficacy studies related to a license with a third party to use their specific binding proteins in the development, manufacturing and commercialization of products. The amount was capitalized as an indefinite-lived intangible asset.

During the six months ended June 30, 2023, the Company decided to terminate a program. Consequently, impairment charges of KUSD 743 (corresponding to the entire carrying amount of the capitalized licenses) was recognized and charged to R&D expenses in the unaudited condensed consolidated interim statement of operations. No impairment losses were recognized during the six months ended June 30, 2022. The Company performs an assessment at the end of each period to determine whether there is any indication that an intangible asset may be impaired. The Company identified one indicator of impairment during the six months ended June 30, 2023. The Company evaluated further and concluded there were no impairments, other than the terminated program.

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The table below provides a rollforward of the Company’s intangible assets as of June 30, 2023 and 2022.

(in KUSD)			Indefinite lived												Definite lived
Cost			Licenses						Internal development costs						Internal development costs						Licenses						Software						Total
January 1, 2023			13,680						—						954						1,052						278						15,964
Additions			—						—						—						—						20						20
Exchange differences			—						—						—						—						3						3
June 30, 2023			13,680						—						954						1,052						301						15,987
Accumulated Amortization
January 1, 2023			(1,295)						—						—						(125)						(184)						(1,604)
Amortization charge			—						—						(38)						(38)						(27)						(103)
Impairment charge			(743)						—						—						—						—						(743)
Exchange differences			—						—												—						(1)						(1)
June 30, 2023			(2,038)						—						(38)						(163)						(212)						(2,451)
Net book amount as of June 30, 2023			11,642						—						916						889						89						13,536
Cost
January 1, 2022			12,985						631						—						1,052						176						14,844
Additions			695						263						—						—						97						1,055
Exchange differences			—						—						—						—						(7)						(7)
June 30, 2022			13,680						894						—						1,052						266						15,892
Accumulated Amortization
January 1, 2022			(1,069)						—						—						(50)						(143)						(1,262)
Amortization charge			—						—						—						(37)						(20)						(57)
Exchange differences			—												—						—						2						2
June 30, 2022			(1,069)						—						—						(87)						(161)						(1,317)
Net book amount as of June 30, 2022			12,611						894						—						965						105						14,575

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The Company is invested in a joint venture company, Overland ADCT BioPharma, with Overland Pharmaceuticals (“Overland”), to develop and commercialize one of the Company’s ADC products, ZYNLONTA, and three of the Company’s ADC product candidates, ADCT-601, ADCT-602 and ADCT-901, in greater China and Singapore. The table below provides a rollforward of the Company’s interest in Overland ADCT BioPharma as of June 30, 2023 and 2022, respectively.

(in KUSD)
Interest in joint venture
January 1, 2023						31,152
Share of comprehensive loss in joint venture						(2,830)
June 30, 2023						28,322
January 1, 2022						41,236
Share of comprehensive loss in joint venture						(4,419)
June 30, 2022						36,817

As of June 30, 2023, the deferred gain of USD 23.5 million arising from the Company’s contribution for its equity investment in the joint venture remained unchanged from December 31, 2022. The Company’s carrying value of its investment in a joint venture increases or decreases in relation to the Company’s proportionate share of comprehensive income or loss of the joint venture. When the Company’s share of losses of a joint venture exceeds the Company’s interest in that joint venture less the carrying value of the deferred gain described above, the Company ceases to recognize its share of further losses. Additional losses are recognized only to the extent that the Company has incurred legal or constructive obligations or made payments on behalf of the joint venture.

The tables below provide summarized financial information for Overland ADCT BioPharma that is material to the Company. The following information reflects the amounts presented in the financial statements of Overland ADCT BioPharma and not the Company’s share of those amounts.

(in KUSD)						As of
Summarized Balance Sheet						June 30, 2023						December 31, 2022
Cash and cash equivalents						11,033						19,261
Prepaid and other current assets						218						2
Intangible assets						49,249						49,249
Total liabilities						(2,493)						(3,062)
Net assets						58,007						65,450
Summarized Statement of Comprehensive Loss						Three months ended June 30,												Six months ended June 30,
						2023						2022						2023						2022
Loss from operations						3,021						4,576						5,528						9,367
Other expense (income)						(1,457)						(662)						(1,183)						(704)
Other comprehensive loss (income)						908						—						1,431						—
Total comprehensive loss						2,472						3,914						5,776						8,663

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The table below provides a rollforward of the Company's right-of-use assets as of June 30, 2023 and 2022, respectively.

(in KUSD)
Right-of-Use Assets						Properties (Offices)						Vehicles						Total
Cost
January 1, 2023						9,311						134						9,445
Additions						4,818						—						4,818
Exchange difference						332						—						332
June 30, 2023						14,461						134						14,595
Accumulated depreciation
January 1, 2023						(2,642)						(83)						(2,725)
Depreciation charge						(830)						(16)						(846)
Exchange difference						(53)						—						(53)
June 30, 2023						(3,525)						(99)						(3,624)
Net book amount as of June 30, 2023						10,936						35						10,971
Cost
January 1, 2022						9,005						134						9,139
Exchange difference						(523)						—						(523)
June 30, 2022						8,482						134						8,616
Accumulated depreciation
January 1, 2022						(1,925)						(50)						(1,975)
Depreciation charge						(589)						(17)						(606)
Exchange difference						59						—						59
June 30, 2022						(2,455)						(67)						(2,522)
Net book amount as of June 30, 2022						6,027						67						6,094

On January 30, 2023, the Company expanded the square footage of its existing lease related to its U.K. office. The lease commenced on January 30, 2023 and expires on January 27, 2031, and includes an option to terminate early on January 26, 2026. The Company is reasonably certain it will not terminate the lease early and therefore will account for the lease using an eight-year lease term. Total rent payments including service charges through January 27, 2031 are USD 7.6 million.

Depreciation of right-of-use assets have been charged to the following categories in the unaudited condensed consolidated interim statement of operations. Depreciation expense for S&M expenses was not material for any of the periods presented.

						Three months ended June 30,												Six months ended June 30,
(in KUSD)						2023						2022						2023						2022
R&D expenses						392						238						723						483
G&A expenses						61						61						123						123
						453						299						846						606

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The table below provides a rollforward of the Company's lease liabilities as of June 30, 2023 and 2022, respectively.

(in KUSD)
Lease liabilities						Properties (Offices)						Vehicles						Total
January 1, 2023						7,607						54						7,661
Additions						4,818						—						4,818
Cash outflow (including interest)						(695)						(19)						(714)
Interest						256						1						257
Exchange difference						370						2						372
June 30, 2023						12,356						38						12,394
January 1, 2022						7,898						125						8,023
Cash outflow (including interest)						(593)						(18)						(611)
Interest						100						1						101
Exchange difference						(575)						(39)						(614)
June 30, 2022						6,830						69						6,899
June 30, 2023
Lease liabilities (short-term)						1,606						26						1,632
Lease liabilities (long-term)						10,750						12						10,762
Total lease liabilities						12,356						38						12,394
June 30, 2022
Lease liabilities (short-term)						875						34						909
Lease liabilities (long-term)						5,955						35						5,990
Total lease liabilities						6,830						69						6,899

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Oak Tree and Owl Rock Warrant Obligations

During the three and six months ended June 30, 2023, the Company recognized (expense) income of KUSD (39) and KUSD 617, respectively, as a result of changes in the fair value of the warrant obligations. The fair value of the warrant obligations as of June 30, 2023 and December 31, 2022 was KUSD 378 and KUSD 995, respectively. The decrease in fair value of the warrant obligation from December 31, 2022 to June 30, 2023 was primarily due to the decrease in the fair value of the underlying shares during that period, which was recorded directly to Non-operating (expense) income in the unaudited condensed consolidated interim statement of operations. See note 8, "Other income (expense)" for further information.

The Company used an independent valuation firm to assist in calculating the fair value of the warrant obligations, using the Black-Scholes option-pricing model. Key inputs for the valuation of the warrant obligations as of June 30, 2023 and December 31, 2022 were as follows:

			As of						As of
			June 30, 2023						December 31, 2022
Exercise price in USD			8.30						8.30
Share price in USD			2.15						3.84
Risk-free interest rate			4.3		%				4.0		%
Expected volatility			80		%				80		%
Expected term (months)			49.5 months						55.5 months
Dividend yield			—						—
Black-Scholes value in USD			0.72						1.89

Senior Secured Term Loan

For the three and six months ended June 30, 2023, the Company recorded interest expense on the senior secured term loan in the amount of KUSD 4,480 and KUSD 9,020, respectively, which was recorded in Financial expense in the unaudited condensed consolidated interim statement of operations. The EIR at June 30, 2023 was 16.79%. The carrying value of the senior secured term loan was USD 111.2 million as of June 30, 2023, of which USD 13.9 million and USD 97.4 million represented the short-term and long-term portion of the liability, respectively.

Pursuant to this Loan Agreement, the Company is subject to a covenant that requires it to maintain a balance at the end of each quarter of at least USD 60.0 million in cash and cash equivalents that are included on the unaudited condensed consolidated interim balance sheet plus an amount equal to any accounts payable that remain unpaid more than ninety days after the date of the original invoice. As of June 30, 2023, the Company was in compliance with this covenant.

On April 24, 2020, the Company entered into a USD 115.0 million Facility Agreement with Deerfield, pursuant to which Deerfield extended a tranche of USD 65.0 million of convertible loans on May 19, 2020 upon completion of the Company’s initial public offering (the “Deerfield First Tranche”) and a tranche of USD 50.0 million of convertible loans on May 17, 2021 after the receipt of regulatory approval for ZYNLONTA (the “Deerfield Second Tranche”).

On August 15, 2022, pursuant to an exchange agreement with Deerfield, Deerfield exchanged USD 115.0 million aggregate principal amount of the Company's senior secured convertible notes for warrants to purchase an aggregate of 4,412,840 common shares, an aggregate of 2,390,297 common shares and cash equal to USD 117.3 million.

As a result of the exchange agreement on August 15, 2022, the Company recognized a loss on extinguishment of USD 42.1 million, which primarily consists of the difference between the aggregate principal amount and carrying value of the convertible loans, exit fee, as well as the unpaid interest payments through the maturity date.

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Embedded conversion option derivatives

Prior to the exchange, the Company accounted for the Facility agreement as a loan and embedded conversion option features. The embedded conversion option derivative was marked-to-market while the loan was measured at its amortized cost on a quarterly basis.

The following table summarizes the changes in fair value income of the embedded conversion option derivatives during the three and six months June 30, 2022:

			Three months ended June 30,									Six months ended June 30,
(in KUSD)						2022						2022
Deerfield First Tranche						8,860						18,378
Deerfield Second Tranche - after FDA approval						5,595						11,932
Total						14,455						30,310

The decrease in fair value of the embedded derivatives was primarily due to a decrease in the fair value of the underlying shares during the three and six months ended June 30, 2022. These amounts were charged directly to the unaudited condensed consolidated interim statements of operations. See note 8, “Other income (expense)” for further information.

The Company used an independent valuation firm to assist in calculating the fair value of the Deerfield First Tranche and Deerfield Second Tranche of the embedded conversion option derivatives, which is based on the mean of values derived from application of the Hull and Goldman Sachs convertible bond pricing models. Key inputs for the valuations as of June 30, 2022 was as follows:

Deerfield First Tranche

			As of
			June 30, 2022
Exercise price at 130% of the IPO price of 19.00, in USD			24.70
Forced conversion price, in USD			67.93
Share price in USD			7.95
Risk-free interest rate			3.0		%
Expected volatility			86		%
Expected term (months)			34.0 months
Dividend yield			—
Recovery rate			5		%
Implied bond yield			12.0		%

Deerfield Second Tranche

						As of
						June 30, 2022
Exercise price in USD						28.07
Forced conversion price, in USD						77.19
Share price in USD						7.95
Risk-free interest rate						3.0		%
Expected volatility						86		%
Expected term (months)						34.0 months
Dividend yield						—
Recovery rate						5		%
Implied bond yield						12.0		%

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Residual convertible loan

The following table summarizes the interest expense recorded on the convertible loan for the three and six months ended June 30, 2022:

						Three months ended June 30,						Six months ended June 30,
(in KUSD)						2022						2022
Deerfield First Tranche						2,313						4,532
Deerfield Second Tranche						813						1,616
Total						3,126						6,148

Pursuant to the exchange agreement with Deerfield entered into on August 15, 2022, the Company issued warrants to purchase an aggregate of 4,412,840 common shares. The warrants consist of warrants to purchase an aggregate of 2,631,578 common shares at an exercise price of USD 24.70 per share and warrants to purchase an aggregate of 1,781,262 common shares at an exercise price of USD 28.07 per share. Each warrant is exercisable, on a cash or a cashless basis, at the option of the holder, at any time on or prior to May 19, 2025. The warrants contain customary anti-dilution adjustments and entitle holders to receive any dividends or other distributions paid on the underlying common shares prior to their expiration on an as-exercised basis. Each holder also may require the Company to repurchase the warrants for their Black Scholes-based fair value in connection with certain transformative transactions or change of control of the Company that occur prior to their expiration.

The terms of the warrants are reflective of the terms of the embedded conversion option features of the Deerfield Facility Agreement prior to the Exchange Agreement. As a result, the fair value of the warrants was determined to approximate the fair value of the existing embedded conversion option features immediately prior to the consummation of the Exchange Agreement. As such, the warrant obligation was recorded at an initial fair value of KUSD 12,297 on August 15, 2022. Subsequent to issuance, the warrant obligation will be remeasured to fair value at the end of each reporting period.

During the three and six months ended June 30, 2023, the Company recognized income of KUSD 20 and 636, respectively, as a result of changes in the fair value of the warrant obligation. The fair value of the warrant obligation as of June 30, 2023 and December 31, 2022 was KUSD 157 and KUSD 793, respectively. The decrease in fair value of the warrant obligation from December 31, 2022 to June 30, 2023 was primarily due to the decrease in the fair value of the underlying shares during that period. These amounts were recorded to Non-operating (expense) income in the unaudited condensed consolidated interim statement of operations. See note 8, "Other income (expense)" for further information.

The Company used an independent valuation firm to assist in calculating the fair value of the Deerfield warrant obligation, using the Black-Scholes option-pricing model. Key inputs for the valuation of the warrant obligation as of June 30, 2023 were as follows:

			As of						As of
			June 30, 2023						December 31, 2022
Exercise price in USD			24.70 and 28.07						24.70 and 28.07
Share price in USD			2.15						3.84
Risk-free interest rate			4.9		%				4.3		%
Expected volatility			80		%				70		%
Expected term (months)			22.7 months						28.7 months
Dividend yield			—						—
Black-Scholes value in USD			0.04 and 0.03						0.20 and 0.16

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Equity Incentive Plan 2019

In November 2019, the Company adopted the Equity Incentive Plan 2019. Under the Equity Incentive Plan 2019, the Company may at its discretion grant to plan participants, such as directors, certain employees and service providers, awards in the form of restricted shares and restricted share units (“RSUs”), share options, share appreciation rights, performance awards and other share-based awards. The Company has reserved 17,741,355 common shares for future issuance under the Equity Incentive Plan 2019 (including share-based equity awards granted to date less awards forfeited). As of June 30, 2023, the Company had 2,564,140 common shares available for the future issuance of share-based equity awards. On March 22, 2023, the Company issued its annual equity award, which was approved by the Compensation Committee of the Board of Directors and consisted of 2,026,341 share options and 538,175 RSUs. As of June 30, 2023, the Company has only granted share options, RSUs and performance awards under the Equity Incentive Plan 2019.

As of June 30, 2023, the cumulative amount recorded as an increase to Other Reserves within equity in the unaudited condensed consolidated interim balance sheet of the Equity Incentive Plan 2019 was KUSD 154,088. The amount of expense for all awards recognized for services received during the three and six months ended June 30, 2023 were KUSD 1,010 and KUSD 8,987, respectively, and for the three and six months ended June 30, 2022 were KUSD 13,818 and KUSD 27,728, respectively. An amount of KUSD 512 was withheld for tax charges during the three and six months ended June 30, 2022.

Equity Exchange Program

On March 6, 2023, the Company commenced a tender offer with employees to exchange some or all of their eligible stock options based on a pre-determined exchange ratio for new options as detailed in our Schedule TO filed March 6, 2023 with the Securities and Exchange Commission (the “Exchange Offer”), to, among other things, further align employee incentives with the current market conditions. The Exchange Offer expired on April 3, 2023 and new options were granted on April 4, 2023. Employees holding stock options to purchase 2.2 million common shares, with exercise prices ranging from USD 8.12 per share to USD 48.77 per share, participated in the Exchange Offer, and 0.9 million new options were granted based on the exchange ratios set forth in the Exchange Offer. The new options have an exercise price of USD 2.06 per share, which is equal to the closing price of the Company’s common shares as reported on the NYSE on April 4, 2023. The new options include additional vesting conditions. Any previously held options that were vested at the time of exchange will fully vest on April 4, 2024. With respect to any options held that were unvested at the time of grant, a portion of the new options will vest on the first anniversary date with additional portions vesting monthly thereafter until the new options are fully vested five years after the original grant date.

Under IFRS 2, the incremental compensation expense of a modified award is measured as the excess of the fair value of each award of new options granted to participants in this Exchange Offer, measured as of the date the new options are granted, over the fair value of the eligible options replaced in exchange for the new options, measured immediately prior to the replacement. The Company utilized a binomial valuation model and determined there was no incremental share-based compensation expense associated with the new options granted under this Exchange Offer. The Company will continue to recognize share-based compensation expense equal to the grant date fair value of the exchanged options.

Share Options

Pursuant to the Equity Incentive Plan 2019, the Company may grant share options to its directors, certain employees and service providers working for the benefit of the Company at the time. The exercise price per share option is set by the Company at the fair market value of the underlying common shares on the date of grant, as determined by the Company, which is generally the closing share price of the Company’s common shares traded on the NYSE. The awards generally vest 25% on the first anniversary of the date of grant, and thereafter evenly on a monthly basis over the subsequent three years. The contractual term of each share option award granted is ten years. Under the grant, the options may be settled only in common shares of the Company. Therefore, the grants of share options under the Equity Incentive Plan 2019 have been accounted for as equity-settled under IFRS 2. As such, the Company records a charge for the vested portion of award grants and for partially earned but non-vested portions of award grants. This results in a front-loaded charge to the Company’s unaudited condensed consolidated interim statement of operations and a corresponding increase to Other Reserves within equity on the unaudited condensed consolidated interim balance sheet.

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The (income) expense recognized for services received during the three and six months ended June 30, 2023 was KUSD (715) and KUSD 4,066, respectively, and for the three and six months ended June 30, 2022 were KUSD 8,450 and KUSD 18,965, respectively.

The following table summarizes the share option awards outstanding as of June 30, 2023:

			Average strike price per share in USD						Number of awards						Weighted average remaining life in years
December 31, 2022			18.30						10,755,494						8.46
Granted			2.47						3,140,641						8.71
Option Exchange - Granted			2.06						898,585						8.71
Forfeited			16.14						(1,303,983)						N/A
Option Exchange - Forfeited			22.55						(2,197,458)						N/A
June 30, 2023			11.93						11,293,279						8.31

Awards outstanding as of June 30, 2023 and December 31, 2022, expire through 2033 and 2032, respectively. The options granted during 2023 include the Company’s annual equity award discussed above. The grant-date fair value of the options relating to the annual equity awards was USD 1.41 per share. As of June 30, 2023, 3,765,502 awards are vested and exercisable out of the total outstanding awards of 11,293,279 common shares. The weighted average strike price and weighted average remaining life for vested and exercisable awards is USD 23.97 and 6.71 years, respectively.

The fair values of the options granted under the Equity Incentive Plan 2019 were determined on the date of the grant using the Black-Scholes option-pricing model. The Company used an independent valuation firm to assist in calculating the fair value of the award grants per participant.

The fair values of the options granted under the Equity Incentive Plan 2019 during the three and six months ended June 30, 2023 were determined on the date of the grant using the following assumptions:

			Three Months Ended						Three Months Ended						Six Months Ended						Six Months Ended
			June 30, 2023						June 30, 2022						June 30, 2023						June 30, 2022
Share price, in USD			1.96 - 2.38						6.55 - 14.83						1.96 - 5.45						6.55 - 19.69
Strike price, in USD			1.96 - 2.38						6.55 - 14.83						1.96 - 5.45						6.55 - 19.69
Expected volatility, in %			75% to 80%						70% to 75%						75% to 80%						70% to 75%
Award life, in years			6.08						6.08						6.08						6.08
Expected dividends			—						—						—						—
Risk-free interest rate, in %			3.56% - 4.02%						2.49% - 3.05%						3.39% - 4.13%						1.46% - 3.05%

The expected volatility was based on the Company’s historical volatility and selected volatility determined by median values observed among other comparable public companies. The award life is based on the time interval between the date of grant and the date during the ten-year life after which, when making the grant, the Company expected on average that participants would exercise their options.

The fair value of the new options granted under the Equity Exchange program was estimated at the date of grant using a binomial model with the following assumptions: Share price of USD 2.06, expected volatility of 77% - 79%, expected risk-free interest rate of 3.29% - 3.31%, expected dividends of 0% and expected term was derived based on the contractual term of the options, the expected exercise behavior and expected post-vesting forfeiture rates. The Company used an independent valuation firm to assist in calculating the fair value of the new award grants per participant.

RSUs

Pursuant to the Equity Incentive Plan 2019, the Company may grant RSUs to its directors, certain employees and service providers working for the benefit of the Company at the time. The awards generally vest annually over a period of three

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years commencing on the first anniversary of the date of grant. The RSUs may be settled only in common shares of the Company. Therefore, the grants of RSUs under the Equity Incentive Plan 2019 have been accounted for as equity-settled under IFRS 2. As such, the Company records a charge for the vested portion of award grants and for partially earned but non-vested portions of award grants. This results in a front-loaded charge to the Company’s unaudited condensed consolidated interim statement of operations and a corresponding increase to Other Reserves within equity on the unaudited condensed consolidated interim balance sheet.

The expense recognized for services received during the three and six months ended June 30, 2023 was KUSD 1,725 and KUSD 4,921, respectively, and for the three and six months ended June 30, 2022 were KUSD 5,368 and KUSD 8,763, respectively.

			Number of awards						Weighted average grant date fair value
December 31, 2022			1,585,877						13.26
Granted			979,680						2.13
Vested			(1,269,106)						8.73
Forfeited			(187,552)						9.25
June 30, 2023			1,108,899						9.30

The RSUs granted during 2023 include the annual equity award on March 22, 2023 discussed above which had a grant date fair value of USD 1.99.

Share-based Compensation Reserves

The movement in the Share-based Compensation Reserves (included in Other reserves within equity) is as follows:

			Three months ended												Six months ended
(in KUSD)			June 30, 2023						June 30, 2022						June 30, 2023						June 30, 2022
Equity Incentive Plan 2019 - Share Options			(715)						8,450						4,066						18,965
Equity Incentive Plan 2019 - RSUs			1,725						5,368						4,921						8,763
ESPP Expense			108						—						205						—
Tax and social charge deductions - Incentive Plan 2019			—						—						—						(512)
Total			1,118						13,818						9,192						27,216

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On August 25, 2021, the Company entered into a royalty purchase agreement with HCR for up to USD 325.0 million of which the Company received gross proceeds of USD 225.0 million during 2021 and received an additional USD 75.0 million in June 2023 upon the first commercial sale of ZYNLONTA in the United Kingdom or any European Union country.

The table below provides a rollforward of the Company’s debt obligation relating to the royalty purchase agreement.

(in KUSD)
January 1, 2022						225,477
Less: royalty payments						10,998
Plus: interest expense						23,200
Less: cumulative catch-up adjustment, Financial income						15,402
December 31, 2022						222,277
Plus: Additional proceeds from the sale of future royalties						75,000
Less: Transaction costs						1,898
Less: royalty payments						6,230
Plus: interest expense						11,575
Plus: cumulative catch-up adjustment, Financial expense						5,288
June 30, 2023						306,012

The Company recorded a liability relating to the initial gross proceeds received less transaction costs in August 2021 and increased the liability in June 2023 for the eligible amount received upon the first commercial sale of ZYNLONTA in the United Kingdom or any European Union country less transaction costs. To determine the accretion of the liability related to the deferred royalty obligation, the Company is required to estimate the total amount of future royalty payments and estimated timing of such payment to HCR based on the Company's revenue projections. Based on the Company's initial revenue projections, the Company used an independent valuation firm to assist in determining the total amount of future royalty payments and estimated timing of such payment to HCR using an option pricing Monte Carlo simulation model. The amount ultimately received by the Company will be accreted to the total amount of the royalty payments necessary to extinguish the Company’s obligation under the agreement, which will be recorded as interest expense over the life of the royalty purchase agreement. The estimate of this total interest expense resulted in an EIR of 10%. As royalty payments are made to HCR, the balance of the debt obligation will be effectively repaid over the life of the royalty purchase agreement.

Based on the Company's periodic review, the exact amount and timing of repayment is likely to be different each reporting period as compared to those estimated based on the Company's initial revenue projections. A significant increase or decrease in actual net sales of ZYNLONTA compared to the Company’s revenue projections, and regulatory approval and commercialization of Cami, as well as ZYNLONTA in other indications as well as licensing revenue could change the royalty rate and royalty cap due to HCR, which could materially impact the debt obligation as well as interest expense associated with the royalty purchase agreement. Also, the Company’s total obligation to HCR can vary depending on the achievement of the sales milestones as well as the timing of a change in control event. The Company will periodically assess the expected payments to HCR based on its underlying revenue projections and to the extent the amount or timing of such payments is materially different than its initial estimates it will record a cumulative catch-up adjustment.

Based on the Company's 2023 updated development plans, and the transaction costs related to the eligible amount received in June 2023, the Company updated the valuation model, which resulted in a cumulative catch-up adjustment of USD 5.3 million recorded as Financial expense within the unaudited condensed consolidated interim statement of operations for the six months ended June 30, 2023. Under the cumulative catch-up method, the EIR is not revised when actual or estimated net sales differ from those estimated as of the inception of the debt obligation. Instead, the carrying amount of the debt obligation is adjusted to an amount equal to the present value of the estimated remaining future payments, discounted by using the original EIR, 10%, as of the date on which the estimate changes.

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Parties are considered to be related if one party has the ability, directly or indirectly, to control the other party or exercise significant influence over the other party in making financial and operating decisions. The Company has identified the following related parties and related transactions.

A.T. Holdings II Sàrl (“AT Holdings II”) is a shareholder in the Company. AT Holdings II is in turn ultimately wholly owned by Auven Therapeutics Holdings, L.P. (“ATH”), a limited partnership registered in the British Virgin Islands. ATH’s General Partner is Auven Therapeutics General L.P., which itself is a limited partnership whose General Partner is Auven Therapeutics GP Ltd. The manager of ATH is Auven Therapeutics Management L.L.L.P. (“ATM”). As a result, ATH is considered a related party.

Based on the Company’s contribution and equity interest in Overland ADCT BioPharma, certain of the Company’s employees serve on its board of directors. As a result, Overland ADCT BioPharma is considered a related party.

Services provided by the Company to related parties

The Company provides certain administrative services to three subsidiaries of ATH and provides Overland ADCT BioPharma clinical supply for use in trials and supply for early access programs, the amounts of which have been deemed immaterial.

As contemplated by the license agreement with Overland ADCT BioPharma, Overland ADCT BioPharma has elected to participate in certain of the Company’s global clinical trials, in exchange for which it reimburses the Company for a portion of the cost of those trials. Overland ADCT BioPharma also reimburses the Company for certain expenses in connection with technology transfer and assistance of clinical personnel. During the three and six months ended June 30, 2023, the Company incurred KUSD 1,244 and KUSD 2,310, respectively, of clinical trial and service costs to be reimbursed by Overland ADCT BioPharma, which is recorded as a reduction of R&D expenses in the Company’s unaudited condensed consolidated interim statement of operations (three and six months ended June 30, 2022: KUSD 876 and KUSD 1,196, respectively).

Related party balances

The Company had a related party receivable balance with Overland ADCT BioPharma of KUSD 1,482 and KUSD 805 as of June 30, 2023 and December 31, 2022, respectively. There was KUSD 20 in trade accounts payable with related parties as of December 31, 2022. There were no trade accounts payable with related parties as of June 30, 2023.

Key management compensation

The compensation of key management is shown below:

			Three months ended June 30,												Six months ended June 30,
(in KUSD)			2023						2022						2023						2022
Salaries and other short-term employee costs			2,587						2,062						6,218						4,206
Pension costs			36						71						231						204
Share-based compensation expense			3,068						6,875						6,712						12,449
Other compensation			33						8						71						18
Total			5,724						9,016						13,232						16,877

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			Three Months Ended June 30,												Six Months Ended June 30,
(in KUSD, except per share amounts)			2023						2022						2023						2022
Loss attributable to owners			(47,117)						(64,374)						(106,543)						(81,035)
Weighted average number of shares outstanding			81,471,127						76,911,713						81,140,287						76,866,968
Basic and diluted loss per share			(0.58)						(0.84)						(1.31)						(1.05)

For the three and six months ended June 30, 2023, basic and diluted loss per share are calculated on the weighted average number of shares issued and outstanding and exclude shares to be issued under the Equity Incentive Plan 2019, 2022 ESPP and the Company’s warrant agreements, as the effect of including those shares would be anti-dilutive. For the three and six months ended June 30, 2022, basic and diluted loss per share are calculated on the weighted average number of shares issued and outstanding and exclude shares to be issued under the 2019 Equity Incentive Plan and the conversion of the principal amount of the convertible loans into the Company’s common shares as the effect of including those shares would be anti-dilutive. See note 16, “Share-based compensation expense,” note 13, “Senior secured term loan facility and warrants,” note 15, “Deerfield warrants” and note 14, “Convertible loans” for further information.

Potentially dilutive securities that were not included in the diluted per share calculations because the effect of including them would be anti-dilutive were as follows:

									Six Months Ended June 30,
															2023						2022
Equity Incentive Plan 2019 - Share Options															11,293,279						8,066,461
Equity Incentive Plan 2019 - RSUs															1,108,899						1,354,432
Conversion of the principal amount of convertible loans into the Company’s common shares															—						4,412,840
Outstanding warrants															4,940,135						—
															17,342,313						13,833,733

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v3.23.2

Cover	6 Months Ended
	Jun. 30, 2023
Cover [Abstract]
Document Type	6-K
Document Period End Date	Jun. 30, 2023
Entity File Number	001-39071
Entity Registrant Name	ADC Therapeutics SA
Entity Address, Address Line One	Biopôle
Entity Address, Address Line Two	Route de la Corniche 3B
Entity Address, Postal Zip Code	1066
Entity Address, City or Town	Epalinges
Entity Address, Country	CH
Entity Central Index Key	0001771910
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2

v3.23.2

Condensed Consolidated Interim Statement of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Condensed Income Statements, Captions [Line Items]
Total revenue	$ 19,283	$ 17,291	$ 38,275	$ 63,789
Cost of product sales	(1,319)	(2,266)	(1,909)	(2,795)
Research and development expenses	(31,944)	(48,537)	(71,424)	(97,489)
Selling and marketing expenses	(14,456)	(17,659)	(29,807)	(36,029)
General and administrative expenses	(11,353)	(18,240)	(26,496)	(37,251)
Total operating expense	(59,072)	(86,702)	(129,636)	(173,564)
Loss from operations	(39,789)	(69,411)	(91,361)	(109,775)
Other income (expense)
Financial income	2,372	16	4,547	18,324
Financial expense	(15,857)	(8,801)	(26,145)	(18,018)
Non-operating (expense) income	(453)	12,875	(456)	26,317
Total other (expense) income	(13,938)	4,090	(22,054)	26,623
Loss before taxes	(53,727)	(65,321)	(113,415)	(83,152)
Income tax benefit	6,610	947	6,872	2,117
Net loss	$ (47,117)	(64,374)	$ (106,543)	(81,035)
Net loss attributable to:
Owners of the parent		$ (64,374)		$ (81,035)
Net loss per share
Net loss per share, basic (in USD per share)	$ (0.58)	$ (0.84)	$ (1.31)	$ (1.05)
Net loss per share, diluted (in dollars per share)	$ (0.58)	$ (0.84)	$ (1.31)	$ (1.05)
Product revenues, net
Condensed Income Statements, Captions [Line Items]
Total revenue	$ 19,197	$ 17,291	$ 38,150	$ 33,789
License revenues and royalties
Condensed Income Statements, Captions [Line Items]
Total revenue	$ 0	$ 0	$ 0	$ 30,000

v3.23.2

Condensed Consolidated Interim Statement of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Profit or loss [abstract]
Net loss	$ (47,117)	$ (64,374)	$ (106,543)	$ (81,035)
Other comprehensive income (loss)
Remeasurement of defined benefit pension liability	0	3,618	0	3,618
Total items that will not be reclassified to profit and loss	0	3,618	0	3,618
Items that may be reclassified to profit and loss
Currency translation differences	169	(383)	310	(541)
Share of other comprehensive loss in joint venture	(444)	0	(700)	0
Total items that may be reclassified to profit and loss	(275)	(383)	(390)	(541)
Other comprehensive (loss) income for the period	(275)	3,235	(390)	3,077
Total comprehensive loss for the period	(47,392)	(61,139)	(106,933)	(77,958)
Total comprehensive loss attributable to:
Owners of the parent	$ (47,392)	$ (61,139)	$ (106,933)	$ (77,958)

v3.23.2

Condensed Consolidated Interim Balance Sheet - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 347,510	$ 326,441
Accounts receivable, net	23,866	72,971
Inventory	19,428	18,564
Other current assets	22,004	28,039
Total current assets	412,808	446,015
Non-current assets
Property, plant and equipment	5,400	3,261
Right-of-use assets	10,971	6,720
Intangible assets	13,536	14,360
Interest in joint venture	28,322	31,152
Deferred tax asset	34,822	26,757
Other long-term assets	1,443	903
Total non-current assets	94,494	83,153
Total assets	507,302	529,168
Current liabilities
Accounts payable	11,691	12,351
Other current liabilities	53,397	73,035
Lease liabilities, short-term	1,632	1,097
Senior secured term loans, short-term	13,861	12,474
Total current liabilities	80,581	98,957
Non-current liabilities
Warrant obligations	535	1,788
Deferred royalty obligation, long-term	299,279	212,353
Deferred gain of joint venture	23,539	23,539
Lease liabilities, long-term	10,762	6,564
Other long-term liabilities	3,839	0
Total non-current liabilities	435,310	341,484
Total liabilities	515,891	440,441
Equity attributable to owners of the parent
Share capital	7,312	7,312
Share premium	1,007,755	1,007,452
Treasury shares	(557)	(679)
Other reserves	164,175	155,683
Cumulative translation adjustments	(46)	(356)
Accumulated losses	(1,187,228)	(1,080,685)
Total equity attributable to owners of the parent	(8,589)	88,727
Total liabilities and equity	507,302	529,168
Senior Secured Term Loans
Non-current liabilities
Convertible loans, long-term	$ 97,356	$ 97,240

v3.23.2

Condensed Consolidated Interim Statement of Changes in Equity - USD ($) $ in Thousands	Total	Share Capital	Share Premium	Other Reserves	Treasury Shares	Cumulative Translation Adjustments	Accumulated Losses
Equity, beginning balance at Dec. 31, 2021	$ 166,088	$ 6,445	$ 981,827	$ 102,646	$ (128)	$ 183	$ (924,885)
Loss for the period	(81,035)						(81,035)
Translation adjustment	(541)					(541)
Remeasurement of defined benefit pension liability	3,618			(3,618)
Share of other comprehensive loss in joint venture	0
Other comprehensive (loss) income for the period	3,077			3,618		(541)
Total comprehensive loss for the period	(77,958)			3,618		(541)	(81,035)
Vestings of RSUs	0		(9)		9
Share-based compensation expense	27,216			27,216
Increase (decrease) through transactions with owners, equity	27,216		(9)	27,216	9
Equity, ending balance at Jun. 30, 2022	115,346	6,445	981,818	133,480	(119)	(358)	(1,005,920)
Equity, beginning balance at Mar. 31, 2022	162,667	6,445	981,818	116,044	(119)	25	(941,546)
Loss for the period	(64,374)						(64,374)
Translation adjustment	(383)					(383)
Remeasurement of defined benefit pension liability	3,618			(3,618)
Share of other comprehensive loss in joint venture	0
Other comprehensive (loss) income for the period	3,235			3,618		(383)
Total comprehensive loss for the period	(61,139)			3,618		(383)	(64,374)
Share-based compensation expense	13,818			13,818
Increase (decrease) through transactions with owners, equity	13,818			13,818	0
Equity, ending balance at Jun. 30, 2022	115,346	6,445	981,818	133,480	(119)	(358)	(1,005,920)
Equity, beginning balance at Dec. 31, 2022	88,727	7,312	1,007,452	155,683	(679)	(356)	(1,080,685)
Loss for the period	(106,543)						(106,543)
Translation adjustment	310					310
Remeasurement of defined benefit pension liability	0
Share of other comprehensive loss in joint venture	(700)			700
Other comprehensive (loss) income for the period	(390)			(700)		310
Total comprehensive loss for the period	(106,933)			(700)		310	(106,543)
Vestings of RSUs	0		111		(111)
Issuance of shares, 2022 Employee Stock Purchase Plan	(425)		(414)		(11)
Share-based compensation expense	9,192			9,192
Increase (decrease) through transactions with owners, equity	9,617	0	303	9,192	122
Equity, ending balance at Jun. 30, 2023	(8,589)	7,312	1,007,755	164,175	(557)	(46)	(1,187,228)
Equity, beginning balance at Mar. 31, 2023	37,685	7,312	1,007,843	163,501	(645)	(215)	(1,140,111)
Loss for the period	(47,117)						(47,117)
Translation adjustment	169					169
Remeasurement of defined benefit pension liability	0
Share of other comprehensive loss in joint venture	(444)			(444)
Other comprehensive (loss) income for the period	(275)			(444)		169
Total comprehensive loss for the period	(47,392)			(444)		169	(47,117)
Vestings of RSUs	0		(88)		88
Share-based compensation expense	1,118			1,118
Increase (decrease) through transactions with owners, equity	1,118	0	(88)	1,118	88
Equity, ending balance at Jun. 30, 2023	$ (8,589)	$ 7,312	$ 1,007,755	$ 164,175	$ (557)	$ (46)	$ (1,187,228)

v3.23.2

Condensed Consolidated Interim Statement of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash used in operating activities
Loss for the period	$ (106,543)	$ (81,035)
Adjustments for non-monetary items:
Share-based compensation expense	9,192	27,216
Impairments of assets	872	1,937
Depreciation of property, plant and equipment	514	517
Amortization of intangible assets	103	57
Impairment of intangible assets	743	0
Depreciation of right-of-use assets	846	606
Share of results in joint venture	2,130	4,419
Deferred tax asset	(8,065)	(7,991)
Change in defined benefit pension liability	0	132
Convertible loans, derivatives, change in fair value	0	(30,310)
Warrant obligations, change in fair value	(1,253)	0
Employee stock purchase plan deductions	244	0
Financial expense (income)	21,341	(407)
Exchange differences	90	(272)
Operating loss before working capital changes	(79,786)	(85,131)
Decrease in accounts receivable, net	49,089	9,355
Decrease in other current assets	(2,079)	(4,282)
Decrease in other current assets	1,422	3,797
Increase in other long-term assets	(738)	0
(Decrease) increase in accounts payable	(2,562)	970
Increase in income taxes	1,192	5,874
Decrease in other current liabilities	(16,297)	(791)
Increase in other long-term liabilities	3,839	0
Cash used in operating activities	(45,920)	(70,208)
Interest paid	(7,779)	(3,562)
Interest received	5,167	36
Interest expense on lease obligations	257	101
Payments made under royalty financing transaction	(6,230)	(4,446)
Tax refund/(payments)	2,909	(8,813)
Net cash used in operating activities	(51,596)	(86,892)
Cash used in investing activities
Payment for purchase of property, plant and equipment	(2,208)	(279)
Payment for purchase of intangible assets	(20)	(1,648)
Refund/(payment) for deposits	200	(210)
Net cash used in investing activities	(2,028)	(2,137)
Cash provided by (used in) financing activities
Proceeds from deferred royalty transaction	75,000	0
Principal portion of lease obligation payments	(457)	(510)
Net cash provided by (used in) financing activities	74,543	(510)
Net decrease in cash and cash equivalents	20,919	(89,539)
Exchange losses on cash and cash equivalents	150	(227)
Cash and cash equivalents at beginning of the period	326,441	466,544
Cash and cash equivalents at end of the period	347,510	376,778
Supplemental Non-Cash Investing Information
Capital expenditures and intangible asset acquisitions recorded in Accounts payable	270	114
Deferred royalty obligation transaction costs recorded in Accounts payable	$ 1,898	$ 0

v3.23.2

Corporate information	6 Months Ended
	Jun. 30, 2023
Corporate information and statement of IFRS compliance [abstract]
Corporate information	Corporate information ADC Therapeutics SA (the “Company” or “ADCT”) was incorporated on June 6, 2011 under the laws of Switzerland. The registered office of the Company is located at Route de la Corniche 3B, 1066 Epalinges, Switzerland. The Company controls three wholly-owned subsidiaries: ADC Therapeutics America, Inc. (“ADCT America”), which was incorporated in Delaware, USA on December 10, 2014, ADC Therapeutics (UK) Ltd (“ADCT UK”), which was incorporated in England on December 12, 2014 and ADC Therapeutics (NL) B.V. which was incorporated in the Netherlands on February 25, 2022. The Company and its three subsidiaries form the ADCT Group (the “Group”). The Group is focused on the development and commercialization of antibody drug conjugates (“ADCs”), including research, development, human clinical trials, regulatory approval and commercialization. On April 23, 2021, the U.S. Food and Drug Administration (“FDA”) approved ZYNLONTA for the treatment of relapsed or refractory diffuse large B-cell lymphoma (“DLBCL”) and the Company commenced recognizing revenue upon the sale of ZYNLONTA during the second quarter of 2021. ADCs are drug constructs which combine monoclonal antibodies specific to particular types of cells with cytotoxic molecules or warheads which seek to kill cancer cells to which the ADC attaches. ADCs have extensive potential therapeutic applications in cancer. These unaudited condensed consolidated interim financial statements were authorized for issue on August 8, 2023. Going concern basis ADCT is a commercial-stage company developing innovative therapeutics. The Group is exposed to all risks inherent in establishing and developing its business, including the substantial uncertainty that current projects will succeed. The Group’s success may also depend on its ability to: •establish and maintain a strong patent position and protection; •develop, gain regulatory approval and commercialize drug products; •enter into collaborations with partners in the pharmaceutical industry; •acquire and retain key personnel; and •acquire additional funding to support its operations. Since its incorporation, the Group has primarily funded its growth through capital increases and additional funds provided by research collaborations, license agreements, the issuance of the Company’s common shares, the issuance of convertible loans, the issuance of term loans and proceeds from a royalty purchase agreement. The Group does not have recourse to bank loans. As a result, the Group is not exposed to liquidity risk through requests for early repayment of loans, other than, pursuant to the senior secured term loan facility, it must maintain a balance of at least USD 60.0 million in cash and cash equivalents plus any accounts payable that are greater than ninety days old at the end of each quarter. As of June 30, 2023, the Group’s cash and cash equivalents amounted to USD 347.5 million (December 31, 2022: USD 326.4 million). Management believes that the Group has sufficient resources to meet its financial obligations for at least the next 12 months from the date of issuance of these unaudited condensed consolidated interim financial statements and, as a result, is presenting these unaudited condensed consolidated interim financial statements of the Group on a going concern basis.

v3.23.2

Basis of preparation	6 Months Ended
	Jun. 30, 2023
Corporate information and statement of IFRS compliance [abstract]
Basis of preparation	Basis of preparation Statement of Compliance These unaudited condensed consolidated interim financial statements as of and for the three and six months ended June 30, 2023 have been prepared in accordance with International Accounting Standard 34 Interim Financial Reporting (“IAS 34”) and should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2022. Functional and reporting currency These unaudited condensed consolidated interim financial statements are presented in United States Dollars (“USD” or “$”), which is the Company’s functional currency and the Group’s reporting currency. A subsidiary of the Company, ADCT UK, has a functional currency of the British Pound (“GBP”). The following exchange rates have been used for the translation of the financial statements of ADCT UK: Six Months Ended June 30, 2023 2022 USD / GBP Closing rate, GBP 1 1.26627  1.21470  Weighted average exchange rate, GBP 1 1.24535  1.20080  Basis of Consolidation The unaudited condensed consolidated interim financial statements incorporate the financial statements of the Company and entities controlled by the Company which are the same as those contained in the audited consolidated financial statements as of and for the year ended December 31, 2022. Use of estimates and judgements The preparation of the unaudited condensed consolidated interim financial statements in conformity with IAS 34 requires management to make judgements, estimates and assumptions that affect the application of accounting policies and the reported amounts of assets and liabilities, income and expense. Actual results may differ from these estimates. Estimates are based on management’s knowledge of current events and actions that the Company may undertake in the future. Estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the period in which the estimate is revised if the revision affects only that period, or in the period of the revision and future periods if the revision affects both current and future periods. In preparing these unaudited condensed consolidated interim financial statements, the significant judgements made by management in applying the Group’s accounting policies and the key sources of estimation uncertainty included those that applied to the consolidated financial statements for the year ended December 31, 2022. There have been no material changes to the use of estimates and judgements other than those described in note 3, "Significant accounting policies."

v3.23.2

Significant accounting policies	6 Months Ended
	Jun. 30, 2023
Accounting Policies, Changes in Accounting Estimates And Errors [Abstract]
Significant accounting policies	Significant accounting policies The accounting policies applied by the Company in these unaudited condensed consolidated interim financial statements are the same as those applied by the Company in its audited consolidated financial statements as of and for the year ended December 31, 2022 and have been applied consistently to all periods presented in these unaudited condensed consolidated interim financial statements, except for the following: Revenue Recognition Product Revenue The Company generates revenue from sales of ZYNLONTA in the U.S. for the treatment of relapsed or refractory DLBCL, which was approved by the FDA on April 23, 2021 and launched shortly thereafter. Revenue is recognized when control is transferred to the customer at the net selling price, which includes reductions for gross-to-net (“GTN”) sales adjustments such as government rebates, chargebacks, distributor service fees, other rebates and administrative fees, sales returns and allowances and sales discounts. On November 15, 2021, the Infrastructure Investment and Jobs Act was enacted, which added a requirement for manufacturers of certain single-source drugs (including biologics and biosimilars) separately paid for under Medicare Part B for at least 18 months and marketed in single-dose containers or packages (known as refundable single-dose container or single-use package drugs) to provide annual refunds if those portions of the dispensed drug that are unused and discarded exceed an applicable percentage defined by statute or regulation. The Centers for Medicare & Medicaid Services (the “CMS”) finalized regulations to implement this section on November 18, 2022, and the provision went into effect on January 1, 2023. The Company has accounted for this annual refund (“discarded drug rebate”) as a GTN sales adjustment beginning in the first quarter of 2023. The discarded drug rebate will involve significant estimates and judgment after considering factors including legal interpretations of applicable laws and regulations, historical experience with discarded volumes and processing time lags. The Company uses information from external sources to identify the Company’s discarded volumes and estimate the discarded drug rebate. The Company’s estimates are subject to inherent limitations of estimates that rely on third-party information and reflect other limitations including lags between the date as of which third-party information is generated and the date on which the Company receives third-party information. Estimates for the discarded drug rebate are being assessed each period and adjusted as required to revise information or actual experience. New and amended IFRS standards There are no new IFRS standards, amendments to standards or interpretations that are mandatory for the financial year beginning on January 1, 2023, that are relevant to the Group. New standards, amendments to standards and interpretations that are not yet effective, which have been deemed by the Group as currently not relevant, are not listed here.

v3.23.2

Financial risk management	6 Months Ended
	Jun. 30, 2023
Financial Instruments [Abstract]
Financial risk management	Financial risk management  4.1Financial risk factors The Group’s activities are exposed to a variety of financial risks: market risk (including changes in the Company’s share price, exposure to fluctuation in currency exchange rates and exposure to interest rate movements), credit risk and liquidity risk. The unaudited condensed consolidated interim financial statements do not include all financial risk management information and disclosures required in the annual financial statements, and should be read in conjunction with the Group’s consolidated financial statements as of December 31, 2022. In relation to the royalty purchase agreement with entities managed by Healthcare Royalty Management, LLC ("HCR"), the Company is obligated to pay interest in the form of royalties in connection with certain net sales and licensing revenue. As the effective interest rate ("EIR") on the deferred royalty obligation does not depend on market performance, the exposure to interest rate and market risk is deemed low. See note 17, “Deferred royalty obligation” for further information. In regards to the senior secured term loans, the interest rate is variable and dependent upon market factors. The Company will update the EIR at the end of each reporting period for changes in the rate. See note 13, "Senior secured term loan facility and warrants" for further information. A hypothetical 100 basis point increase (decrease) in the interest rate as of June 30, 2023 would have increased (decreased) the effective interest expense associated with the Company's senior secured term loan facility by KUSD 910 and (KUSD 910). There have been no other material changes in financial risk management since December 31, 2022. 4.2Fair value estimation As of June 30, 2023, the carrying amount is a reasonable approximation of fair value for the following financial assets and liabilities: •Cash and cash equivalents •Trade accounts receivable; and •Trade accounts payable In the six months ended June 30, 2023, there were no significant changes in the business or economic circumstances that affected the fair value of the Group’s financial assets and financial liabilities. Fair values must be estimated at the end of each reporting period with regard to the senior secured term loan warrant obligation and the Deerfield warrants. The approach to valuation follows the grant date fair value principle, and the key input factors are described for the senior secured term loan facility warrant obligation in note 13, "Senior secured term loan facility and warrants" and for the Deerfield warrants in note 15, "Deerfield warrants." Commonly accepted pricing models (Black-Scholes) have been used to calculate the fair values. The valuation of the senior secured term loan facility warrant obligation and Deerfield warrants are classified as pertaining to Level 2 of the valuation hierarchy. The convertible loan derivatives previously were classified as pertaining to Level 3 of the valuation hierarchy and were extinguished on August 15, 2022. See note 14, "Convertible loans" for further information. The Company no longer has any inputs pertaining to level 3 of the valuation hierarchy set out below. The different levels of the valuation hierarchy have been defined as follows: (a)Level 1: quoted prices (unadjusted) in active markets for identical assets or liabilities; (b)Level 2: inputs other than quoted prices that are observable for the asset or liability, either directly (for example, as prices) or indirectly (for example, derived from prices); (c)Level 3: inputs for the asset or liability that are not based on observable market data. There were no transfers between the respective levels during the period.

v3.23.2

Revenue recognition	6 Months Ended
	Jun. 30, 2023
Revenue From Contracts With Customers [Abstract]
Revenue recognition	Revenue recognition The table below provides a disaggregation of revenues by type of service and customer location for the three and six months ended June 30, 2023 and June 30, 2022. Three months ended June 30, Six months ended June 30, (in KUSD) 2023 2022 2023 2022 Types of goods and services Product revenue, net 19,197  17,291  38,150  33,789  License revenues —  —  —  30,000  Royalties 86  —  125  —  Total revenue 19,283  17,291  38,275  63,789  Customer Location U.S. 19,197  17,291  38,150  33,789  EMEA(1) 86  —  125  —  Japan —  —  —  30,000  Total revenue 19,283  17,291  38,275  63,789  (1) Europe, the Middle East and Africa Product revenue, net Product revenues, net from sales of ZYNLONTA were KUSD 19,197 and KUSD 38,150 for the three and six months ended June 30, 2023. Product revenues, net from the sales of ZYNLONTA were KUSD 17,291 and KUSD 33,789 for the three and six months ended June 30, 2022, respectively. The Company records its best estimate of GTN sales adjustments to which customers are likely to be entitled. The table below provides a rollforward of the Company’s accruals related to the GTN sales adjustments for the three and six months ended June 30, 2023 and June 30, 2022. Three months ended June 30, Six months ended June 30, (in KUSD) 2023 2022 2023 2022 Beginning balance 4,362  4,126  3,746  2,590  GTN sales adjustments for current period sales 5,783  3,206  11,399  6,697  GTN sales adjustments for prior period sales (229) 87  (877) (105) Credits, payments and reclassifications to Accounts payable (4,182) (3,955) (8,534) (5,718) Ending balance as of June 30, 5,734  3,464  5,734  3,464  The table below provides the classification of the accruals related to the GTN sales adjustment included in the Company’s unaudited condensed consolidated interim balance sheet as of June 30, 2023 and December 31, 2022. (in KUSD) As of June 30, 2023 As of December 31, 2022 Accounts receivable, net 1,677  2,151  Other current liabilities 4,057  1,595  5,734  3,746  License revenues and royalties On January 18, 2022, the Company entered into an exclusive license agreement with MTPC for the development and commercialization of ZYNLONTA for all hematologic and solid tumor indications in Japan. Under the terms of the agreement, the Company received an upfront payment of USD 30 million and may receive up to an additional USD 205 million in milestones if certain development and commercial events are achieved. The Company will also be entitled to receive royalties ranging in percentage from the high teens to the low twenties based on net sales of ZYNLONTA in Japan. MTPC will conduct clinical studies of ZYNLONTA in Japan and will have the right to participate in any global clinical studies by bearing a portion of the study costs. In addition, the Company will supply ZYNLONTA to MTPC for its drug development and commercialization under a supply agreement. On July 8, 2022, the Company entered into exclusive license agreement with Sobi for the development and commercialization of ZYNLONTA for all hematologic and solid tumor indications outside of the U.S., greater China, Singapore and Japan. Under the terms of the agreement, the Company received an upfront payment of USD 55 million and is eligible to receive up to USD 382.5 million in regulatory and net sales-based milestones, of which USD 50 million in license revenue was recognized in December 2022 upon approval of a Marketing Authorisation Application by the European Commission for ZYNLONTA in third-line DLBCL and received in the first quarter of 2023. The Company will also receive royalties ranging in percentage from the mid-teens to the mid-twenties based on net sales of the product in Sobi’s licensed territories, subject to certain adjustments. The Company recognized KUSD 125 of revenue attributable to royalties in the Sobi licensed territories during the six months ended June 30, 2023.

v3.23.2

Segment information	6 Months Ended
	Jun. 30, 2023
Operating Segments [Abstract]
Segment information	Segment informationThe Company is managed and operated as one business. A single management team that reports to the chief executive officer comprehensively manages the entire business. Accordingly, the Company views its business and manages its operations as one operating segment.

v3.23.2

Operating expense	6 Months Ended
	Jun. 30, 2023
Analysis of income and expense [abstract]
Operating expense	Operating expense The following table provides the unaudited condensed consolidated interim statement of operations classification of the Company's total operating expense: (in KUSD) Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Cost of product sales 1,319  2,266  1,909  2,795  R&D External costs (1) 17,947  30,175  39,601  59,343  Employee expenses (2) 13,997  18,362  31,823  38,146  R&D expense 31,944  48,537  71,424  97,489  S&M External costs (1) 8,329  9,259  15,689  18,170  Employee expenses (2) 6,127  8,400  14,118  17,859  S&M expense 14,456  17,659  29,807  36,029  G&A External costs (1) 4,881  5,880  9,419  13,519  Employee expenses (2) 6,472  12,360  17,077  23,732  G&A expense 11,353  18,240  26,496  37,251  Total operating expense 59,072  86,702  129,636  173,564  (1) Includes depreciation expense (2) Includes share-based compensation expense The decrease in Cost of product sales for the three and six months ended June 30, 2023, was primarily driven by higher impairment charges for the three and six months ended June 30, 2022 related to the manufacturing of batches that did not meet the Company's specifications. R&D external costs decreased for the three and six months ended June 30, 2023 as a result of the completion of the phase 2 study in 2022 for Camidanlumab Tesirine (Cami) and our decision to pause the program while we evaluated FDA feedback, continue to assess a potential regulatory pathway and seek a partner to continue developing this program. The Company also had higher cost sharing with our partners, lower clinical trial costs for LOTIS 3, LOTIS 6 and LOTIS 7, as well as lower professional fees related to ZYNLONTA, partially offset by higher clinical trial expenses for LOTIS 5 and LOTIS 9 and in ADCT-212 the Company incurred lower manufacturing expenses related to IND-enabling work. The decrease in external costs was partially offset by an increase in clinical trial costs for ADCT-901 and expenses related to the Company's preclinical product candidates and research pipeline. Employee expense decreased for the three and six months ended June 30, 2023 primarily due to lower share-based compensation expense driven by fluctuations in our share price, voluntary terminations and the workforce reduction announced and put into effect during the second quarter of 2023. The decrease in S&M expenses for the three and six months ended June 30, 2023 was primarily due to lower share-based compensation expense due to the fluctuations in the Company's share price, voluntary terminations and the commercial re-alignment announced and put into effect during the second quarter of 2023, as well as lower spend on marketing, analytics and expenses, including those expenses in the European Union relating to the commercial launch of ZYNLONTA. The decrease in G&A expenses for the three and six months ended June 30, 2023 was attributable to lower share-based compensation expense due to fluctuations in the Company's share price, transition of a board member, voluntary terminations and the workforce reduction announced and put into effect during the second quarter of 2023, as well as lower external costs related to insurance and IT, partially offset with higher professional fees. The decrease in G&A expenses for the six months ended June 30, 2023 was also attributable to professional fees associated with the license agreement entered into with MTPC recognized during the six months ended June 30, 2022, partially offset by higher wages and benefits.

v3.23.2

Other income (expense)	6 Months Ended
	Jun. 30, 2023
Analysis of income and expense [abstract]
Other income (expense)	Other income (expense) The components of financial income for the three and six months ended June 30, 2023 and June 30, 2022 are as follows: Three months ended June 30, Six months ended June 30, (in KUSD) Note 2023 2022 2023 2022 Interest income 2,372  16  4,547  36  Cumulative catch-up adjustment, deferred royalty obligation 17 —  —  —  18,288  Financial income 2,372  16  4,547  18,324  The components of financial expense for the three and six months ended June 30, 2023 and June 30, 2022 are as follows: Three months ended June 30, Six months ended June 30, (in KUSD) Note 2023 2022 2023 2022 Cumulative catch-up adjustment, deferred royalty obligation 17 5,417  —  5,288  —  Deferred royalty obligation interest expense 17 5,829  5,545  11,575  11,687  Effective interest expense on senior secured term loan facility 13 4,480  —  9,020  —  Effective interest expense on convertible loans 14 —  3,126  —  6,148  Interest expense on leasing and other 12 131  130  262  183  Financial expense 15,857  8,801  26,145  18,018  The components of non-operating (expense) income for the three and six months ended June 30, 2023 and June 30, 2022 are as follows: Three months ended June 30, Six months ended June 30, (in KUSD) Note 2023 2022 2023 2022 Convertible loans, derivatives, change in fair value income 14 —  14,455  —  30,310  Deerfield warrant obligation, change in fair value income 15 20  —  636  —  Senior secured term loan facility, warrants, change in fair value (expense) income 13 (39) —  617  —  Share of results with joint venture 11 (767) (1,917) (2,130) (4,419) Exchange differences gain (loss) 18  223  (34) 304  R&D tax credit 315  114  455  122  Non-operating (expense) income (453) 12,875  (456) 26,317  Convertible loans, derivatives, change in fair value income Changes in derivative fair values are explained in note 14, “Convertible loans.” Pursuant to the Facility Agreement with Deerfield, the Company drew down the Deerfield First Tranche of the convertible loans amounting to USD 65.0 million on May 19, 2020. Additionally, in connection with the FDA approval of ZYNLONTA, the Company drew down the Deerfield Second Tranche of convertible loans amounting to USD 50.0 million on May 17, 2021. On August 15, 2022, pursuant to the exchange agreement with Deerfield, Deerfield exchanged USD 115.0 million aggregate principal amount of the Company's senior secured convertible notes for warrants to purchase an aggregate of 4,412,840 common shares, an aggregate of 2,390,297 common shares and cash equal to USD 117.3 million. Deerfield warrant obligation, change in fair value income Pursuant to an exchange agreement with Deerfield entered into on August 15, 2022, the Company issued warrants to purchase an aggregate of 4,412,840 common shares. The Deerfield warrant obligation has been recorded at its initial fair value and is remeasured to fair value at the end of each reporting period. Changes in fair value of the Deerfield warrant obligation are explained in note 15, "Deerfield warrants." Senior secured term loan facility, warrants, change in fair value (expense) income The Company has accounted for the First Tranche of the senior secured term loan and warrants as one hybrid financial instrument, with the USD 120.0 million proceeds separated into two components: a warrant obligation and a loan. The warrant obligation has been recorded at its initial fair value and is remeasured to fair value at the end of each reporting period. Changes in fair value of the warrant obligation are explained in note 13, "Senior secured term loan facility and warrants." Share of results with joint venture In connection with the formation of Overland ADCT BioPharma in December 2020, the Company recorded its proportionate share of Overland ADCT BioPharma’s comprehensive loss. See note 11, “Interest in joint venture.” Exchange differences gain (loss) Also included in non-operating (expense) income are favorable or unfavorable Exchange differences. The Company is exposed to foreign exchange risk arising from various currency exposures, primarily with respect to British pounds, Euros and Swiss francs. Exchange differences represent gain or (loss) based on favorable or unfavorable changes in foreign currencies. R&D tax credit The Company recognizes as income (expense) amounts received and receivable by its subsidiary, ADCT UK, under the United Kingdom’s R&D Expenditure Credit scheme (“UK R&D Credit Scheme”). The grants represent 20% of eligible expenditures for the three months ended June 30, 2023 and represent 13% of eligible expenditures for the three months ended March 31, 2023. The grants represent 12% of eligible expenditures for the three and six months ended June 30, 2022. The claims are payable through the tax system, as a refund of corporation tax or of other taxes, including income tax and social security payments deducted at source from qualifying (research) employees’ payroll and VAT. The relevant amounts have been therefore presented net in the balance sheet. As the credit is independent of ADCT UK’s taxable profit, is clearly designed to incentivize companies to invest in R&D activities and is itself taxable income, the Group has recognized the income as government grants within non-operating (expense) income and not as a credit to income tax expense.

v3.23.2

Inventory	6 Months Ended
	Jun. 30, 2023
Inventory [Abstract]
Inventory	Inventory Inventory as of June 30, 2023 and December 31, 2022 consisted of the following: (in KUSD) As of June 30, 2023 As of December 31, 2022 Work in process 19,015  18,165  Finished goods 413  399  Total inventory 19,428  18,564  Impairment charges of KUSD 726 and KUSD 872 were recognized and charged to cost of product sales in the unaudited condensed consolidated interim statement of operations during the three and six months ended June 30, 2023, respectively. For the three and six months ended June 30, 2022, the Company designated certain capitalized pre-approval ZYNLONTA inventory for R&D use and recorded a charge to R&D expenses, which was partially offset by a reversal of previously recorded impairment charges. The net impact of KUSD 436 and KUSD 75 was recorded as an expense to R&D in the Company’s unaudited condensed consolidated interim statement of operation for the three and six months ended June 30, 2022, respectively. The reversal of previously recorded impairment charges is based on the existence of inventory on hand and estimated demand, as well as expiration dating.

v3.23.2

Intangible assets	6 Months Ended
	Jun. 30, 2023
Intangible Assets [Abstract]
Intangible assets	Intangible assets During the six months ended June 30, 2023, the Company did not capitalize any license fees as intangible assets. During the six months ended June 30, 2022, the Company capitalized the following milestone payments as intangible assets: •An amount of KUSD 500 paid upon the dosing of a specific number of patients in the first in-human clinical study related to an antibody the Company acquired from a third party to be used in research, development, manufacturing and commercialization. The amount was capitalized as an indefinite-lived intangible asset; and •    An amount of KUSD 195 paid upon the successful completion of in-vivo efficacy studies related to a license with a third party to use their specific binding proteins in the development, manufacturing and commercialization of products. The amount was capitalized as an indefinite-lived intangible asset. During the six months ended June 30, 2023, the Company decided to terminate a program. Consequently, impairment charges of KUSD 743 (corresponding to the entire carrying amount of the capitalized licenses) was recognized and charged to R&D expenses in the unaudited condensed consolidated interim statement of operations. No impairment losses were recognized during the six months ended June 30, 2022. The Company performs an assessment at the end of each period to determine whether there is any indication that an intangible asset may be impaired. The Company identified one indicator of impairment during the six months ended June 30, 2023. The Company evaluated further and concluded there were no impairments, other than the terminated program. The table below provides a rollforward of the Company’s intangible assets as of June 30, 2023 and 2022. (in KUSD) Indefinite lived Definite lived Cost Licenses Internal development costs Internal development costs Licenses Software Total January 1, 2023 13,680  —  954  1,052  278  15,964  Additions —  —  —  —  20  20  Exchange differences —  —  —  —  3  3  June 30, 2023 13,680  —  954  1,052  301  15,987  Accumulated Amortization January 1, 2023 (1,295) —  —  (125) (184) (1,604) Amortization charge —  —  (38) (38) (27) (103) Impairment charge (743) —  —  —  —  (743) Exchange differences —  —  —  (1) (1) June 30, 2023 (2,038) —  (38) (163) (212) (2,451) Net book amount as of June 30, 2023 11,642  —  916  889  89  13,536  Cost January 1, 2022 12,985  631  —  1,052  176  14,844  Additions 695  263  —  —  97  1,055  Exchange differences —  —  —  —  (7) (7) June 30, 2022 13,680  894  —  1,052  266  15,892  Accumulated Amortization January 1, 2022 (1,069) —  —  (50) (143) (1,262) Amortization charge —  —  —  (37) (20) (57) Exchange differences —  —  —  2  2  June 30, 2022 (1,069) —  —  (87) (161) (1,317) Net book amount as of June 30, 2022 12,611  894  —  965  105  14,575

v3.23.2

Interest in joint venture	6 Months Ended
	Jun. 30, 2023
Interests In Other Entities [Abstract]
Interest in joint venture	The Company is invested in a joint venture company, Overland ADCT BioPharma, with Overland Pharmaceuticals (“Overland”), to develop and commercialize one of the Company’s ADC products, ZYNLONTA, and three of the Company’s ADC product candidates, ADCT-601, ADCT-602 and ADCT-901, in greater China and Singapore. The table below provides a rollforward of the Company’s interest in Overland ADCT BioPharma as of June 30, 2023 and 2022, respectively. (in KUSD) Interest in joint venture January 1, 2023 31,152  Share of comprehensive loss in joint venture (2,830) June 30, 2023 28,322  January 1, 2022 41,236  Share of comprehensive loss in joint venture (4,419) June 30, 2022 36,817  As of June 30, 2023, the deferred gain of USD 23.5 million arising from the Company’s contribution for its equity investment in the joint venture remained unchanged from December 31, 2022. The Company’s carrying value of its investment in a joint venture increases or decreases in relation to the Company’s proportionate share of comprehensive income or loss of the joint venture. When the Company’s share of losses of a joint venture exceeds the Company’s interest in that joint venture less the carrying value of the deferred gain described above, the Company ceases to recognize its share of further losses. Additional losses are recognized only to the extent that the Company has incurred legal or constructive obligations or made payments on behalf of the joint venture. The tables below provide summarized financial information for Overland ADCT BioPharma that is material to the Company. The following information reflects the amounts presented in the financial statements of Overland ADCT BioPharma and not the Company’s share of those amounts. (in KUSD) As of Summarized Balance Sheet June 30, 2023 December 31, 2022 Cash and cash equivalents 11,033  19,261  Prepaid and other current assets 218  2  Intangible assets 49,249  49,249  Total liabilities (2,493) (3,062) Net assets 58,007  65,450  Summarized Statement of Comprehensive Loss Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Loss from operations 3,021  4,576  5,528  9,367  Other expense (income) (1,457) (662) (1,183) (704) Other comprehensive loss (income) 908  —  1,431  —  Total comprehensive loss 2,472  3,914  5,776  8,663

v3.23.2

Leases	6 Months Ended
	Jun. 30, 2023
Presentation of leases for lessee [abstract]
Leases	Leases The table below provides a rollforward of the Company's right-of-use assets as of June 30, 2023 and 2022, respectively. (in KUSD) Right-of-Use Assets Properties (Offices) Vehicles Total Cost January 1, 2023 9,311  134  9,445  Additions 4,818  —  4,818  Exchange difference 332  —  332  June 30, 2023 14,461  134  14,595  Accumulated depreciation January 1, 2023 (2,642) (83) (2,725) Depreciation charge (830) (16) (846) Exchange difference (53) —  (53) June 30, 2023 (3,525) (99) (3,624) Net book amount as of June 30, 2023 10,936  35  10,971  Cost January 1, 2022 9,005  134  9,139  Exchange difference (523) —  (523) June 30, 2022 8,482  134  8,616  Accumulated depreciation January 1, 2022 (1,925) (50) (1,975) Depreciation charge (589) (17) (606) Exchange difference 59  —  59  June 30, 2022 (2,455) (67) (2,522) Net book amount as of June 30, 2022 6,027  67  6,094  On January 30, 2023, the Company expanded the square footage of its existing lease related to its U.K. office. The lease commenced on January 30, 2023 and expires on January 27, 2031, and includes an option to terminate early on January 26, 2026. The Company is reasonably certain it will not terminate the lease early and therefore will account for the lease using an eight-year lease term. Total rent payments including service charges through January 27, 2031 are USD 7.6 million. Depreciation of right-of-use assets have been charged to the following categories in the unaudited condensed consolidated interim statement of operations. Depreciation expense for S&M expenses was not material for any of the periods presented. Three months ended June 30, Six months ended June 30, (in KUSD) 2023 2022 2023 2022 R&D expenses 392  238  723  483  G&A expenses 61  61  123  123  453  299  846  606  The table below provides a rollforward of the Company's lease liabilities as of June 30, 2023 and 2022, respectively. (in KUSD) Lease liabilities Properties (Offices) Vehicles Total January 1, 2023 7,607  54  7,661  Additions 4,818  —  4,818  Cash outflow (including interest) (695) (19) (714) Interest 256  1  257  Exchange difference 370  2  372  June 30, 2023 12,356  38  12,394  January 1, 2022 7,898  125  8,023  Cash outflow (including interest) (593) (18) (611) Interest 100  1  101  Exchange difference (575) (39) (614) June 30, 2022 6,830  69  6,899  June 30, 2023 Lease liabilities (short-term) 1,606  26  1,632  Lease liabilities (long-term) 10,750  12  10,762  Total lease liabilities 12,356  38  12,394  June 30, 2022 Lease liabilities (short-term) 875  34  909  Lease liabilities (long-term) 5,955  35  5,990  Total lease liabilities 6,830  69  6,899

v3.23.2

Senior secured term loan facility and warrants	6 Months Ended
	Jun. 30, 2023
Financial Instruments [Abstract]
Convertible loans	Senior secured term loan facility and warrants Oak Tree and Owl Rock Warrant Obligations During the three and six months ended June 30, 2023, the Company recognized (expense) income of KUSD (39) and KUSD 617, respectively, as a result of changes in the fair value of the warrant obligations. The fair value of the warrant obligations as of June 30, 2023 and December 31, 2022 was KUSD 378 and KUSD 995, respectively. The decrease in fair value of the warrant obligation from December 31, 2022 to June 30, 2023 was primarily due to the decrease in the fair value of the underlying shares during that period, which was recorded directly to Non-operating (expense) income in the unaudited condensed consolidated interim statement of operations. See note 8, "Other income (expense)" for further information. The Company used an independent valuation firm to assist in calculating the fair value of the warrant obligations, using the Black-Scholes option-pricing model. Key inputs for the valuation of the warrant obligations as of June 30, 2023 and December 31, 2022 were as follows: As of As of June 30, 2023 December 31, 2022 Exercise price in USD 8.30  8.30  Share price in USD 2.15  3.84  Risk-free interest rate 4.3  % 4.0  % Expected volatility 80  % 80  % Expected term (months) 49.5 months 55.5 months Dividend yield —  —  Black-Scholes value in USD 0.72  1.89  Senior Secured Term Loan For the three and six months ended June 30, 2023, the Company recorded interest expense on the senior secured term loan in the amount of KUSD 4,480 and KUSD 9,020, respectively, which was recorded in Financial expense in the unaudited condensed consolidated interim statement of operations. The EIR at June 30, 2023 was 16.79%. The carrying value of the senior secured term loan was USD 111.2 million as of June 30, 2023, of which USD 13.9 million and USD 97.4 million represented the short-term and long-term portion of the liability, respectively. Pursuant to this Loan Agreement, the Company is subject to a covenant that requires it to maintain a balance at the end of each quarter of at least USD 60.0 million in cash and cash equivalents that are included on the unaudited condensed consolidated interim balance sheet plus an amount equal to any accounts payable that remain unpaid more than ninety days after the date of the original invoice. As of June 30, 2023, the Company was in compliance with this covenant. Convertible loans On April 24, 2020, the Company entered into a USD 115.0 million Facility Agreement with Deerfield, pursuant to which Deerfield extended a tranche of USD 65.0 million of convertible loans on May 19, 2020 upon completion of the Company’s initial public offering (the “Deerfield First Tranche”) and a tranche of USD 50.0 million of convertible loans on May 17, 2021 after the receipt of regulatory approval for ZYNLONTA (the “Deerfield Second Tranche”). On August 15, 2022, pursuant to an exchange agreement with Deerfield, Deerfield exchanged USD 115.0 million aggregate principal amount of the Company's senior secured convertible notes for warrants to purchase an aggregate of 4,412,840 common shares, an aggregate of 2,390,297 common shares and cash equal to USD 117.3 million. As a result of the exchange agreement on August 15, 2022, the Company recognized a loss on extinguishment of USD 42.1 million, which primarily consists of the difference between the aggregate principal amount and carrying value of the convertible loans, exit fee, as well as the unpaid interest payments through the maturity date. Embedded conversion option derivatives Prior to the exchange, the Company accounted for the Facility agreement as a loan and embedded conversion option features. The embedded conversion option derivative was marked-to-market while the loan was measured at its amortized cost on a quarterly basis. The following table summarizes the changes in fair value income of the embedded conversion option derivatives during the three and six months June 30, 2022: Three months ended June 30, Six months ended June 30, (in KUSD) 2022 2022 Deerfield First Tranche 8,860  18,378  Deerfield Second Tranche - after FDA approval 5,595  11,932  Total 14,455  30,310  The decrease in fair value of the embedded derivatives was primarily due to a decrease in the fair value of the underlying shares during the three and six months ended June 30, 2022. These amounts were charged directly to the unaudited condensed consolidated interim statements of operations. See note 8, “Other income (expense)” for further information. The Company used an independent valuation firm to assist in calculating the fair value of the Deerfield First Tranche and Deerfield Second Tranche of the embedded conversion option derivatives, which is based on the mean of values derived from application of the Hull and Goldman Sachs convertible bond pricing models. Key inputs for the valuations as of June 30, 2022 was as follows: Deerfield First Tranche As of June 30, 2022 Exercise price at 130% of the IPO price of 19.00, in USD 24.70  Forced conversion price, in USD 67.93  Share price in USD 7.95  Risk-free interest rate 3.0  % Expected volatility 86  % Expected term (months) 34.0 months Dividend yield —  Recovery rate 5  % Implied bond yield 12.0  % Deerfield Second Tranche As of June 30, 2022 Exercise price in USD 28.07  Forced conversion price, in USD 77.19  Share price in USD 7.95  Risk-free interest rate 3.0  % Expected volatility 86  % Expected term (months) 34.0 months Dividend yield —  Recovery rate 5  % Implied bond yield 12.0  % Residual convertible loan The following table summarizes the interest expense recorded on the convertible loan for the three and six months ended June 30, 2022: Three months ended June 30, Six months ended June 30, (in KUSD) 2022 2022 Deerfield First Tranche 2,313  4,532  Deerfield Second Tranche 813  1,616  Total 3,126  6,148

v3.23.2

Convertible loans	6 Months Ended
	Jun. 30, 2023
Financial Instruments [Abstract]
Convertible loans	Senior secured term loan facility and warrants Oak Tree and Owl Rock Warrant Obligations During the three and six months ended June 30, 2023, the Company recognized (expense) income of KUSD (39) and KUSD 617, respectively, as a result of changes in the fair value of the warrant obligations. The fair value of the warrant obligations as of June 30, 2023 and December 31, 2022 was KUSD 378 and KUSD 995, respectively. The decrease in fair value of the warrant obligation from December 31, 2022 to June 30, 2023 was primarily due to the decrease in the fair value of the underlying shares during that period, which was recorded directly to Non-operating (expense) income in the unaudited condensed consolidated interim statement of operations. See note 8, "Other income (expense)" for further information. The Company used an independent valuation firm to assist in calculating the fair value of the warrant obligations, using the Black-Scholes option-pricing model. Key inputs for the valuation of the warrant obligations as of June 30, 2023 and December 31, 2022 were as follows: As of As of June 30, 2023 December 31, 2022 Exercise price in USD 8.30  8.30  Share price in USD 2.15  3.84  Risk-free interest rate 4.3  % 4.0  % Expected volatility 80  % 80  % Expected term (months) 49.5 months 55.5 months Dividend yield —  —  Black-Scholes value in USD 0.72  1.89  Senior Secured Term Loan For the three and six months ended June 30, 2023, the Company recorded interest expense on the senior secured term loan in the amount of KUSD 4,480 and KUSD 9,020, respectively, which was recorded in Financial expense in the unaudited condensed consolidated interim statement of operations. The EIR at June 30, 2023 was 16.79%. The carrying value of the senior secured term loan was USD 111.2 million as of June 30, 2023, of which USD 13.9 million and USD 97.4 million represented the short-term and long-term portion of the liability, respectively. Pursuant to this Loan Agreement, the Company is subject to a covenant that requires it to maintain a balance at the end of each quarter of at least USD 60.0 million in cash and cash equivalents that are included on the unaudited condensed consolidated interim balance sheet plus an amount equal to any accounts payable that remain unpaid more than ninety days after the date of the original invoice. As of June 30, 2023, the Company was in compliance with this covenant. Convertible loans On April 24, 2020, the Company entered into a USD 115.0 million Facility Agreement with Deerfield, pursuant to which Deerfield extended a tranche of USD 65.0 million of convertible loans on May 19, 2020 upon completion of the Company’s initial public offering (the “Deerfield First Tranche”) and a tranche of USD 50.0 million of convertible loans on May 17, 2021 after the receipt of regulatory approval for ZYNLONTA (the “Deerfield Second Tranche”). On August 15, 2022, pursuant to an exchange agreement with Deerfield, Deerfield exchanged USD 115.0 million aggregate principal amount of the Company's senior secured convertible notes for warrants to purchase an aggregate of 4,412,840 common shares, an aggregate of 2,390,297 common shares and cash equal to USD 117.3 million. As a result of the exchange agreement on August 15, 2022, the Company recognized a loss on extinguishment of USD 42.1 million, which primarily consists of the difference between the aggregate principal amount and carrying value of the convertible loans, exit fee, as well as the unpaid interest payments through the maturity date. Embedded conversion option derivatives Prior to the exchange, the Company accounted for the Facility agreement as a loan and embedded conversion option features. The embedded conversion option derivative was marked-to-market while the loan was measured at its amortized cost on a quarterly basis. The following table summarizes the changes in fair value income of the embedded conversion option derivatives during the three and six months June 30, 2022: Three months ended June 30, Six months ended June 30, (in KUSD) 2022 2022 Deerfield First Tranche 8,860  18,378  Deerfield Second Tranche - after FDA approval 5,595  11,932  Total 14,455  30,310  The decrease in fair value of the embedded derivatives was primarily due to a decrease in the fair value of the underlying shares during the three and six months ended June 30, 2022. These amounts were charged directly to the unaudited condensed consolidated interim statements of operations. See note 8, “Other income (expense)” for further information. The Company used an independent valuation firm to assist in calculating the fair value of the Deerfield First Tranche and Deerfield Second Tranche of the embedded conversion option derivatives, which is based on the mean of values derived from application of the Hull and Goldman Sachs convertible bond pricing models. Key inputs for the valuations as of June 30, 2022 was as follows: Deerfield First Tranche As of June 30, 2022 Exercise price at 130% of the IPO price of 19.00, in USD 24.70  Forced conversion price, in USD 67.93  Share price in USD 7.95  Risk-free interest rate 3.0  % Expected volatility 86  % Expected term (months) 34.0 months Dividend yield —  Recovery rate 5  % Implied bond yield 12.0  % Deerfield Second Tranche As of June 30, 2022 Exercise price in USD 28.07  Forced conversion price, in USD 77.19  Share price in USD 7.95  Risk-free interest rate 3.0  % Expected volatility 86  % Expected term (months) 34.0 months Dividend yield —  Recovery rate 5  % Implied bond yield 12.0  % Residual convertible loan The following table summarizes the interest expense recorded on the convertible loan for the three and six months ended June 30, 2022: Three months ended June 30, Six months ended June 30, (in KUSD) 2022 2022 Deerfield First Tranche 2,313  4,532  Deerfield Second Tranche 813  1,616  Total 3,126  6,148

v3.23.2

Deerfield Warrants	6 Months Ended
	Jun. 30, 2023
Subclassifications of assets, liabilities and equities [abstract]
Deerfield Warrants	Deerfield warrants Pursuant to the exchange agreement with Deerfield entered into on August 15, 2022, the Company issued warrants to purchase an aggregate of 4,412,840 common shares. The warrants consist of warrants to purchase an aggregate of 2,631,578 common shares at an exercise price of USD 24.70 per share and warrants to purchase an aggregate of 1,781,262 common shares at an exercise price of USD 28.07 per share. Each warrant is exercisable, on a cash or a cashless basis, at the option of the holder, at any time on or prior to May 19, 2025. The warrants contain customary anti-dilution adjustments and entitle holders to receive any dividends or other distributions paid on the underlying common shares prior to their expiration on an as-exercised basis. Each holder also may require the Company to repurchase the warrants for their Black Scholes-based fair value in connection with certain transformative transactions or change of control of the Company that occur prior to their expiration. The terms of the warrants are reflective of the terms of the embedded conversion option features of the Deerfield Facility Agreement prior to the Exchange Agreement. As a result, the fair value of the warrants was determined to approximate the fair value of the existing embedded conversion option features immediately prior to the consummation of the Exchange Agreement. As such, the warrant obligation was recorded at an initial fair value of KUSD 12,297 on August 15, 2022. Subsequent to issuance, the warrant obligation will be remeasured to fair value at the end of each reporting period. During the three and six months ended June 30, 2023, the Company recognized income of KUSD 20 and 636, respectively, as a result of changes in the fair value of the warrant obligation. The fair value of the warrant obligation as of June 30, 2023 and December 31, 2022 was KUSD 157 and KUSD 793, respectively. The decrease in fair value of the warrant obligation from December 31, 2022 to June 30, 2023 was primarily due to the decrease in the fair value of the underlying shares during that period. These amounts were recorded to Non-operating (expense) income in the unaudited condensed consolidated interim statement of operations. See note 8, "Other income (expense)" for further information. The Company used an independent valuation firm to assist in calculating the fair value of the Deerfield warrant obligation, using the Black-Scholes option-pricing model. Key inputs for the valuation of the warrant obligation as of June 30, 2023 were as follows: As of As of June 30, 2023 December 31, 2022 Exercise price in USD 24.70 and 28.07 24.70 and 28.07 Share price in USD 2.15  3.84  Risk-free interest rate 4.9  % 4.3  % Expected volatility 80  % 70  % Expected term (months) 22.7 months 28.7 months Dividend yield —  —  Black-Scholes value in USD 0.04 and 0.03 0.20 and 0.16

v3.23.2

Share-based compensation	6 Months Ended
	Jun. 30, 2023
Share-based Payment Arrangements [Abstract]
Share-based compensation	Share-based compensation Equity Incentive Plan 2019 In November 2019, the Company adopted the Equity Incentive Plan 2019. Under the Equity Incentive Plan 2019, the Company may at its discretion grant to plan participants, such as directors, certain employees and service providers, awards in the form of restricted shares and restricted share units (“RSUs”), share options, share appreciation rights, performance awards and other share-based awards. The Company has reserved 17,741,355 common shares for future issuance under the Equity Incentive Plan 2019 (including share-based equity awards granted to date less awards forfeited). As of June 30, 2023, the Company had 2,564,140 common shares available for the future issuance of share-based equity awards. On March 22, 2023, the Company issued its annual equity award, which was approved by the Compensation Committee of the Board of Directors and consisted of 2,026,341 share options and 538,175 RSUs. As of June 30, 2023, the Company has only granted share options, RSUs and performance awards under the Equity Incentive Plan 2019. As of June 30, 2023, the cumulative amount recorded as an increase to Other Reserves within equity in the unaudited condensed consolidated interim balance sheet of the Equity Incentive Plan 2019 was KUSD 154,088. The amount of expense for all awards recognized for services received during the three and six months ended June 30, 2023 were KUSD 1,010 and KUSD 8,987, respectively, and for the three and six months ended June 30, 2022 were KUSD 13,818 and KUSD 27,728, respectively. An amount of KUSD 512 was withheld for tax charges during the three and six months ended June 30, 2022. Equity Exchange Program On March 6, 2023, the Company commenced a tender offer with employees to exchange some or all of their eligible stock options based on a pre-determined exchange ratio for new options as detailed in our Schedule TO filed March 6, 2023 with the Securities and Exchange Commission (the “Exchange Offer”), to, among other things, further align employee incentives with the current market conditions. The Exchange Offer expired on April 3, 2023 and new options were granted on April 4, 2023. Employees holding stock options to purchase 2.2 million common shares, with exercise prices ranging from USD 8.12 per share to USD 48.77 per share, participated in the Exchange Offer, and 0.9 million new options were granted based on the exchange ratios set forth in the Exchange Offer. The new options have an exercise price of USD 2.06 per share, which is equal to the closing price of the Company’s common shares as reported on the NYSE on April 4, 2023. The new options include additional vesting conditions. Any previously held options that were vested at the time of exchange will fully vest on April 4, 2024. With respect to any options held that were unvested at the time of grant, a portion of the new options will vest on the first anniversary date with additional portions vesting monthly thereafter until the new options are fully vested five years after the original grant date. Under IFRS 2, the incremental compensation expense of a modified award is measured as the excess of the fair value of each award of new options granted to participants in this Exchange Offer, measured as of the date the new options are granted, over the fair value of the eligible options replaced in exchange for the new options, measured immediately prior to the replacement. The Company utilized a binomial valuation model and determined there was no incremental share-based compensation expense associated with the new options granted under this Exchange Offer. The Company will continue to recognize share-based compensation expense equal to the grant date fair value of the exchanged options. Share Options Pursuant to the Equity Incentive Plan 2019, the Company may grant share options to its directors, certain employees and service providers working for the benefit of the Company at the time. The exercise price per share option is set by the Company at the fair market value of the underlying common shares on the date of grant, as determined by the Company, which is generally the closing share price of the Company’s common shares traded on the NYSE. The awards generally vest 25% on the first anniversary of the date of grant, and thereafter evenly on a monthly basis over the subsequent three years. The contractual term of each share option award granted is ten years. Under the grant, the options may be settled only in common shares of the Company. Therefore, the grants of share options under the Equity Incentive Plan 2019 have been accounted for as equity-settled under IFRS 2. As such, the Company records a charge for the vested portion of award grants and for partially earned but non-vested portions of award grants. This results in a front-loaded charge to the Company’s unaudited condensed consolidated interim statement of operations and a corresponding increase to Other Reserves within equity on the unaudited condensed consolidated interim balance sheet. The (income) expense recognized for services received during the three and six months ended June 30, 2023 was KUSD (715) and KUSD 4,066, respectively, and for the three and six months ended June 30, 2022 were KUSD 8,450 and KUSD 18,965, respectively. The following table summarizes the share option awards outstanding as of June 30, 2023:   Average strike price per share in USD Number of awards Weighted average remaining life in years December 31, 2022 18.30  10,755,494  8.46 Granted 2.47  3,140,641  8.71 Option Exchange - Granted 2.06  898,585  8.71 Forfeited 16.14  (1,303,983) N/A Option Exchange - Forfeited 22.55  (2,197,458) N/A June 30, 2023 11.93  11,293,279  8.31 Awards outstanding as of June 30, 2023 and December 31, 2022, expire through 2033 and 2032, respectively. The options granted during 2023 include the Company’s annual equity award discussed above. The grant-date fair value of the options relating to the annual equity awards was USD 1.41 per share. As of June 30, 2023, 3,765,502 awards are vested and exercisable out of the total outstanding awards of 11,293,279 common shares. The weighted average strike price and weighted average remaining life for vested and exercisable awards is USD 23.97 and 6.71 years, respectively. The fair values of the options granted under the Equity Incentive Plan 2019 were determined on the date of the grant using the Black-Scholes option-pricing model. The Company used an independent valuation firm to assist in calculating the fair value of the award grants per participant. The fair values of the options granted under the Equity Incentive Plan 2019 during the three and six months ended June 30, 2023 were determined on the date of the grant using the following assumptions:   Three Months Ended Three Months Ended Six Months Ended Six Months Ended   June 30, 2023 June 30, 2022 June 30, 2023 June 30, 2022 Share price, in USD 1.96 - 2.38 6.55 - 14.83 1.96 - 5.45 6.55 - 19.69 Strike price, in USD 1.96 - 2.38 6.55 - 14.83 1.96 - 5.45 6.55 - 19.69 Expected volatility, in % 75% to 80% 70% to 75% 75% to 80% 70% to 75% Award life, in years 6.08 6.08 6.08 6.08 Expected dividends — — — — Risk-free interest rate, in % 3.56% - 4.02% 2.49% - 3.05% 3.39% - 4.13% 1.46% - 3.05% The expected volatility was based on the Company’s historical volatility and selected volatility determined by median values observed among other comparable public companies. The award life is based on the time interval between the date of grant and the date during the ten-year life after which, when making the grant, the Company expected on average that participants would exercise their options. The fair value of the new options granted under the Equity Exchange program was estimated at the date of grant using a binomial model with the following assumptions: Share price of USD 2.06, expected volatility of 77% - 79%, expected risk-free interest rate of 3.29% - 3.31%, expected dividends of 0% and expected term was derived based on the contractual term of the options, the expected exercise behavior and expected post-vesting forfeiture rates. The Company used an independent valuation firm to assist in calculating the fair value of the new award grants per participant. RSUs Pursuant to the Equity Incentive Plan 2019, the Company may grant RSUs to its directors, certain employees and service providers working for the benefit of the Company at the time. The awards generally vest annually over a period of three years commencing on the first anniversary of the date of grant. The RSUs may be settled only in common shares of the Company. Therefore, the grants of RSUs under the Equity Incentive Plan 2019 have been accounted for as equity-settled under IFRS 2. As such, the Company records a charge for the vested portion of award grants and for partially earned but non-vested portions of award grants. This results in a front-loaded charge to the Company’s unaudited condensed consolidated interim statement of operations and a corresponding increase to Other Reserves within equity on the unaudited condensed consolidated interim balance sheet. The expense recognized for services received during the three and six months ended June 30, 2023 was KUSD 1,725 and KUSD 4,921, respectively, and for the three and six months ended June 30, 2022 were KUSD 5,368 and KUSD 8,763, respectively. Number of awards   Weighted average grant date fair value December 31, 2022 1,585,877  13.26  Granted 979,680  2.13  Vested (1,269,106) 8.73  Forfeited (187,552) 9.25  June 30, 2023 1,108,899  9.30  The RSUs granted during 2023 include the annual equity award on March 22, 2023 discussed above which had a grant date fair value of USD 1.99. Share-based Compensation Reserves The movement in the Share-based Compensation Reserves (included in Other reserves within equity) is as follows: Three months ended Six months ended (in KUSD) June 30, 2023 June 30, 2022 June 30, 2023 June 30, 2022 Equity Incentive Plan 2019 - Share Options (715) 8,450  4,066  18,965  Equity Incentive Plan 2019 - RSUs 1,725  5,368  4,921  8,763  ESPP Expense 108  —  205  —  Tax and social charge deductions - Incentive Plan 2019 —  —  —  (512) Total 1,118  13,818  9,192  27,216

v3.23.2

Deferred royalty obligation	6 Months Ended
	Jun. 30, 2023
Deferred Royalty Obligation [Abstract]
Deferred royalty obligation	Deferred royalty obligation On August 25, 2021, the Company entered into a royalty purchase agreement with HCR for up to USD 325.0 million of which the Company received gross proceeds of USD 225.0 million during 2021 and received an additional USD 75.0 million in June 2023 upon the first commercial sale of ZYNLONTA in the United Kingdom or any European Union country. The table below provides a rollforward of the Company’s debt obligation relating to the royalty purchase agreement. (in KUSD) January 1, 2022 225,477  Less: royalty payments 10,998  Plus: interest expense 23,200  Less: cumulative catch-up adjustment, Financial income 15,402  December 31, 2022 222,277  Plus: Additional proceeds from the sale of future royalties 75,000  Less: Transaction costs 1,898  Less: royalty payments 6,230  Plus: interest expense 11,575  Plus: cumulative catch-up adjustment, Financial expense 5,288  June 30, 2023 306,012  The Company recorded a liability relating to the initial gross proceeds received less transaction costs in August 2021 and increased the liability in June 2023 for the eligible amount received upon the first commercial sale of ZYNLONTA in the United Kingdom or any European Union country less transaction costs. To determine the accretion of the liability related to the deferred royalty obligation, the Company is required to estimate the total amount of future royalty payments and estimated timing of such payment to HCR based on the Company's revenue projections. Based on the Company's initial revenue projections, the Company used an independent valuation firm to assist in determining the total amount of future royalty payments and estimated timing of such payment to HCR using an option pricing Monte Carlo simulation model. The amount ultimately received by the Company will be accreted to the total amount of the royalty payments necessary to extinguish the Company’s obligation under the agreement, which will be recorded as interest expense over the life of the royalty purchase agreement. The estimate of this total interest expense resulted in an EIR of 10%. As royalty payments are made to HCR, the balance of the debt obligation will be effectively repaid over the life of the royalty purchase agreement. Based on the Company's periodic review, the exact amount and timing of repayment is likely to be different each reporting period as compared to those estimated based on the Company's initial revenue projections. A significant increase or decrease in actual net sales of ZYNLONTA compared to the Company’s revenue projections, and regulatory approval and commercialization of Cami, as well as ZYNLONTA in other indications as well as licensing revenue could change the royalty rate and royalty cap due to HCR, which could materially impact the debt obligation as well as interest expense associated with the royalty purchase agreement. Also, the Company’s total obligation to HCR can vary depending on the achievement of the sales milestones as well as the timing of a change in control event. The Company will periodically assess the expected payments to HCR based on its underlying revenue projections and to the extent the amount or timing of such payments is materially different than its initial estimates it will record a cumulative catch-up adjustment. Based on the Company's 2023 updated development plans, and the transaction costs related to the eligible amount received in June 2023, the Company updated the valuation model, which resulted in a cumulative catch-up adjustment of USD 5.3 million recorded as Financial expense within the unaudited condensed consolidated interim statement of operations for the six months ended June 30, 2023. Under the cumulative catch-up method, the EIR is not revised when actual or estimated net sales differ from those estimated as of the inception of the debt obligation. Instead, the carrying amount of the debt obligation is adjusted to an amount equal to the present value of the estimated remaining future payments, discounted by using the original EIR, 10%, as of the date on which the estimate changes.
Schedule of borrowings	The following table summarizes the interest expense recorded on the convertible loan for the three and six months ended June 30, 2022: Three months ended June 30, Six months ended June 30, (in KUSD) 2022 2022 Deerfield First Tranche 2,313  4,532  Deerfield Second Tranche 813  1,616  Total 3,126  6,148  The table below provides a rollforward of the Company’s debt obligation relating to the royalty purchase agreement. (in KUSD) January 1, 2022 225,477  Less: royalty payments 10,998  Plus: interest expense 23,200  Less: cumulative catch-up adjustment, Financial income 15,402  December 31, 2022 222,277  Plus: Additional proceeds from the sale of future royalties 75,000  Less: Transaction costs 1,898  Less: royalty payments 6,230  Plus: interest expense 11,575  Plus: cumulative catch-up adjustment, Financial expense 5,288  June 30, 2023 306,012

v3.23.2

Related parties	6 Months Ended
	Jun. 30, 2023
Related Party [Abstract]
Related parties	Related parties Parties are considered to be related if one party has the ability, directly or indirectly, to control the other party or exercise significant influence over the other party in making financial and operating decisions. The Company has identified the following related parties and related transactions. A.T. Holdings II Sàrl (“AT Holdings II”) is a shareholder in the Company. AT Holdings II is in turn ultimately wholly owned by Auven Therapeutics Holdings, L.P. (“ATH”), a limited partnership registered in the British Virgin Islands. ATH’s General Partner is Auven Therapeutics General L.P., which itself is a limited partnership whose General Partner is Auven Therapeutics GP Ltd. The manager of ATH is Auven Therapeutics Management L.L.L.P. (“ATM”). As a result, ATH is considered a related party. Based on the Company’s contribution and equity interest in Overland ADCT BioPharma, certain of the Company’s employees serve on its board of directors. As a result, Overland ADCT BioPharma is considered a related party. Services provided by the Company to related parties The Company provides certain administrative services to three subsidiaries of ATH and provides Overland ADCT BioPharma clinical supply for use in trials and supply for early access programs, the amounts of which have been deemed immaterial. As contemplated by the license agreement with Overland ADCT BioPharma, Overland ADCT BioPharma has elected to participate in certain of the Company’s global clinical trials, in exchange for which it reimburses the Company for a portion of the cost of those trials. Overland ADCT BioPharma also reimburses the Company for certain expenses in connection with technology transfer and assistance of clinical personnel. During the three and six months ended June 30, 2023, the Company incurred KUSD 1,244 and KUSD 2,310, respectively, of clinical trial and service costs to be reimbursed by Overland ADCT BioPharma, which is recorded as a reduction of R&D expenses in the Company’s unaudited condensed consolidated interim statement of operations (three and six months ended June 30, 2022: KUSD 876 and KUSD 1,196, respectively). Related party balances The Company had a related party receivable balance with Overland ADCT BioPharma of KUSD 1,482 and KUSD 805 as of June 30, 2023 and December 31, 2022, respectively. There was KUSD 20 in trade accounts payable with related parties as of December 31, 2022. There were no trade accounts payable with related parties as of June 30, 2023. Key management compensation The compensation of key management is shown below: Three months ended June 30, Six months ended June 30, (in KUSD) 2023 2022 2023   2022 Salaries and other short-term employee costs 2,587  2,062  6,218  4,206  Pension costs 36  71  231  204  Share-based compensation expense 3,068  6,875  6,712  12,449  Other compensation 33  8  71  18  Total 5,724  9,016  13,232  16,877

v3.23.2

Loss per share	6 Months Ended
	Jun. 30, 2023
Earnings per share [abstract]
Loss per share	Loss per share   Three Months Ended June 30,   Six Months Ended June 30, (in KUSD, except per share amounts) 2023   2022   2023   2022 Loss attributable to owners (47,117) (64,374) (106,543) (81,035) Weighted average number of shares outstanding 81,471,127  76,911,713  81,140,287  76,866,968  Basic and diluted loss per share (0.58) (0.84) (1.31) (1.05) For the three and six months ended June 30, 2023, basic and diluted loss per share are calculated on the weighted average number of shares issued and outstanding and exclude shares to be issued under the Equity Incentive Plan 2019, 2022 ESPP and the Company’s warrant agreements, as the effect of including those shares would be anti-dilutive. For the three and six months ended June 30, 2022, basic and diluted loss per share are calculated on the weighted average number of shares issued and outstanding and exclude shares to be issued under the 2019 Equity Incentive Plan and the conversion of the principal amount of the convertible loans into the Company’s common shares as the effect of including those shares would be anti-dilutive. See note 16, “Share-based compensation expense,” note 13, “Senior secured term loan facility and warrants,” note 15, “Deerfield warrants” and note 14, “Convertible loans” for further information. Potentially dilutive securities that were not included in the diluted per share calculations because the effect of including them would be anti-dilutive were as follows: Six Months Ended June 30, 2023   2022 Equity Incentive Plan 2019 - Share Options 11,293,279  8,066,461  Equity Incentive Plan 2019 - RSUs 1,108,899  1,354,432  Conversion of the principal amount of convertible loans into the Company’s common shares —  4,412,840  Outstanding warrants 4,940,135  —  17,342,313  13,833,733

v3.23.2

Events after the reporting date	6 Months Ended
	Jun. 30, 2023
Events After Reporting Period [Abstract]
Events after the reporting date	Events after the reporting dateThe Company has evaluated its subsequent events through August 8, 2023, the date the financial statements were available to be issued, and has concluded that there are no subsequent events requiring disclosure in the unaudited condensed consolidated interim financial statements, other than the item described below.

v3.23.2

Significant accounting policies (Policies)	6 Months Ended
	Jun. 30, 2023
Accounting Policies, Changes in Accounting Estimates And Errors [Abstract]
Statement of Compliance	Statement of Compliance These unaudited condensed consolidated interim financial statements as of and for the three and six months ended June 30, 2023 have been prepared in accordance with International Accounting Standard 34 Interim Financial Reporting (“IAS 34”) and should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2022.
Functional and reporting currency	Functional and reporting currency These unaudited condensed consolidated interim financial statements are presented in United States Dollars (“USD” or “$”), which is the Company’s functional currency and the Group’s reporting currency.
Use of estimates and judgements	Use of estimates and judgements The preparation of the unaudited condensed consolidated interim financial statements in conformity with IAS 34 requires management to make judgements, estimates and assumptions that affect the application of accounting policies and the reported amounts of assets and liabilities, income and expense. Actual results may differ from these estimates. Estimates are based on management’s knowledge of current events and actions that the Company may undertake in the future. Estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the period in which the estimate is revised if the revision affects only that period, or in the period of the revision and future periods if the revision affects both current and future periods. In preparing these unaudited condensed consolidated interim financial statements, the significant judgements made by management in applying the Group’s accounting policies and the key sources of estimation uncertainty included those that applied to the consolidated financial statements for the year ended December 31, 2022. There have been no material changes to the use of estimates and judgements other than those described in note 3, "Significant accounting policies."
Revenue Recognition	Revenue Recognition Product Revenue The Company generates revenue from sales of ZYNLONTA in the U.S. for the treatment of relapsed or refractory DLBCL, which was approved by the FDA on April 23, 2021 and launched shortly thereafter. Revenue is recognized when control is transferred to the customer at the net selling price, which includes reductions for gross-to-net (“GTN”) sales adjustments such as government rebates, chargebacks, distributor service fees, other rebates and administrative fees, sales returns and allowances and sales discounts. On November 15, 2021, the Infrastructure Investment and Jobs Act was enacted, which added a requirement for manufacturers of certain single-source drugs (including biologics and biosimilars) separately paid for under Medicare Part B for at least 18 months and marketed in single-dose containers or packages (known as refundable single-dose container or single-use package drugs) to provide annual refunds if those portions of the dispensed drug that are unused and discarded exceed an applicable percentage defined by statute or regulation. The Centers for Medicare & Medicaid Services (the “CMS”) finalized regulations to implement this section on November 18, 2022, and the provision went into effect on January 1, 2023. The Company has accounted for this annual refund (“discarded drug rebate”) as a GTN sales adjustment beginning in the first quarter of 2023. The discarded drug rebate will involve significant estimates and judgment after considering factors including legal interpretations of applicable laws and regulations, historical experience with discarded volumes and processing time lags. The Company uses information from external sources to identify the Company’s discarded volumes and estimate the discarded drug rebate. The Company’s estimates are subject to inherent limitations of estimates that rely on third-party information and reflect other limitations including lags between the date as of which third-party information is generated and the date on which the Company receives third-party information. Estimates for the discarded drug rebate are being assessed each period and adjusted as required to revise information or actual experience.
New and amended IFRS standards	New and amended IFRS standards There are no new IFRS standards, amendments to standards or interpretations that are mandatory for the financial year beginning on January 1, 2023, that are relevant to the Group. New standards, amendments to standards and interpretations that are not yet effective, which have been deemed by the Group as currently not relevant, are not listed here.

v3.23.2

Basis of preparation (Tables)	6 Months Ended
	Jun. 30, 2023
Corporate information and statement of IFRS compliance [abstract]
Schedule of Foreign currency exchange rate	A subsidiary of the Company, ADCT UK, has a functional currency of the British Pound (“GBP”). The following exchange rates have been used for the translation of the financial statements of ADCT UK: Six Months Ended June 30, 2023 2022 USD / GBP Closing rate, GBP 1 1.26627  1.21470  Weighted average exchange rate, GBP 1 1.24535  1.20080

v3.23.2

Product revenues, net (Tables)	6 Months Ended
	Jun. 30, 2023
Revenue From Contracts With Customers [Abstract]
Disclosure Of Detailed Information About Sales Adjustments Explanatory	The table below provides a disaggregation of revenues by type of service and customer location for the three and six months ended June 30, 2023 and June 30, 2022. Three months ended June 30, Six months ended June 30, (in KUSD) 2023 2022 2023 2022 Types of goods and services Product revenue, net 19,197  17,291  38,150  33,789  License revenues —  —  —  30,000  Royalties 86  —  125  —  Total revenue 19,283  17,291  38,275  63,789  Customer Location U.S. 19,197  17,291  38,150  33,789  EMEA(1) 86  —  125  —  Japan —  —  —  30,000  Total revenue 19,283  17,291  38,275  63,789  (1) Europe, the Middle East and Africa The table below provides a rollforward of the Company’s accruals related to the GTN sales adjustments for the three and six months ended June 30, 2023 and June 30, 2022. Three months ended June 30, Six months ended June 30, (in KUSD) 2023 2022 2023 2022 Beginning balance 4,362  4,126  3,746  2,590  GTN sales adjustments for current period sales 5,783  3,206  11,399  6,697  GTN sales adjustments for prior period sales (229) 87  (877) (105) Credits, payments and reclassifications to Accounts payable (4,182) (3,955) (8,534) (5,718) Ending balance as of June 30, 5,734  3,464  5,734  3,464
Disclosure Of Detailed Information About Sales Adjustment Included In the Balance Sheets	The table below provides the classification of the accruals related to the GTN sales adjustment included in the Company’s unaudited condensed consolidated interim balance sheet as of June 30, 2023 and December 31, 2022. (in KUSD) As of June 30, 2023 As of December 31, 2022 Accounts receivable, net 1,677  2,151  Other current liabilities 4,057  1,595  5,734  3,746

v3.23.2

Operating expense (Tables)	6 Months Ended
	Jun. 30, 2023
Analysis of income and expense [abstract]
Disclosure Of Detailed Information About Expenses By Nature Explanatory	The following table provides the unaudited condensed consolidated interim statement of operations classification of the Company's total operating expense: (in KUSD) Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Cost of product sales 1,319  2,266  1,909  2,795  R&D External costs (1) 17,947  30,175  39,601  59,343  Employee expenses (2) 13,997  18,362  31,823  38,146  R&D expense 31,944  48,537  71,424  97,489  S&M External costs (1) 8,329  9,259  15,689  18,170  Employee expenses (2) 6,127  8,400  14,118  17,859  S&M expense 14,456  17,659  29,807  36,029  G&A External costs (1) 4,881  5,880  9,419  13,519  Employee expenses (2) 6,472  12,360  17,077  23,732  G&A expense 11,353  18,240  26,496  37,251  Total operating expense 59,072  86,702  129,636  173,564  (1) Includes depreciation expense (2) Includes share-based compensation expense

v3.23.2

Other income (expense) (Tables)	6 Months Ended
	Jun. 30, 2023
Analysis of income and expense [abstract]
Disclosure Of Detailed Information About Financial Income Explanatory	The components of financial income for the three and six months ended June 30, 2023 and June 30, 2022 are as follows: Three months ended June 30, Six months ended June 30, (in KUSD) Note 2023 2022 2023 2022 Interest income 2,372  16  4,547  36  Cumulative catch-up adjustment, deferred royalty obligation 17 —  —  —  18,288  Financial income 2,372  16  4,547  18,324
Disclosure Of Detailed Information About Financial Expense Explanatory	The components of financial expense for the three and six months ended June 30, 2023 and June 30, 2022 are as follows: Three months ended June 30, Six months ended June 30, (in KUSD) Note 2023 2022 2023 2022 Cumulative catch-up adjustment, deferred royalty obligation 17 5,417  —  5,288  —  Deferred royalty obligation interest expense 17 5,829  5,545  11,575  11,687  Effective interest expense on senior secured term loan facility 13 4,480  —  9,020  —  Effective interest expense on convertible loans 14 —  3,126  —  6,148  Interest expense on leasing and other 12 131  130  262  183  Financial expense 15,857  8,801  26,145  18,018
Schedule of Other income (expense)	The components of non-operating (expense) income for the three and six months ended June 30, 2023 and June 30, 2022 are as follows: Three months ended June 30, Six months ended June 30, (in KUSD) Note 2023 2022 2023 2022 Convertible loans, derivatives, change in fair value income 14 —  14,455  —  30,310  Deerfield warrant obligation, change in fair value income 15 20  —  636  —  Senior secured term loan facility, warrants, change in fair value (expense) income 13 (39) —  617  —  Share of results with joint venture 11 (767) (1,917) (2,130) (4,419) Exchange differences gain (loss) 18  223  (34) 304  R&D tax credit 315  114  455  122  Non-operating (expense) income (453) 12,875  (456) 26,317

v3.23.2

Inventory (Tables)	6 Months Ended
	Jun. 30, 2023
Inventory [Abstract]
Disclosure Of Inventory Information Explanatory	Inventory as of June 30, 2023 and December 31, 2022 consisted of the following: (in KUSD) As of June 30, 2023 As of December 31, 2022 Work in process 19,015  18,165  Finished goods 413  399  Total inventory 19,428  18,564

v3.23.2

Intangible assets (Tables)	6 Months Ended
	Jun. 30, 2023
Intangible Assets [Abstract]
Disclosure of reconciliation of changes in intangible assets and goodwill [text block]	below provides a rollforward of the Company’s intangible assets as of June 30, 2023 and 2022. (in KUSD) Indefinite lived Definite lived Cost Licenses Internal development costs Internal development costs Licenses Software Total January 1, 2023 13,680  —  954  1,052  278  15,964  Additions —  —  —  —  20  20  Exchange differences —  —  —  —  3  3  June 30, 2023 13,680  —  954  1,052  301  15,987  Accumulated Amortization January 1, 2023 (1,295) —  —  (125) (184) (1,604) Amortization charge —  —  (38) (38) (27) (103) Impairment charge (743) —  —  —  —  (743) Exchange differences —  —  —  (1) (1) June 30, 2023 (2,038) —  (38) (163) (212) (2,451) Net book amount as of June 30, 2023 11,642  —  916  889  89  13,536  Cost January 1, 2022 12,985  631  —  1,052  176  14,844  Additions 695  263  —  —  97  1,055  Exchange differences —  —  —  —  (7) (7) June 30, 2022 13,680  894  —  1,052  266  15,892  Accumulated Amortization January 1, 2022 (1,069) —  —  (50) (143) (1,262) Amortization charge —  —  —  (37) (20) (57) Exchange differences —  —  —  2  2  June 30, 2022 (1,069) —  —  (87) (161) (1,317) Net book amount as of June 30, 2022 12,611  894  —  965  105  14,575

v3.23.2

Interest in joint venture (Tables)	6 Months Ended
	Jun. 30, 2023
Interests In Other Entities [Abstract]
Schedule of movement in interest in joint venture	The table below provides a rollforward of the Company’s interest in Overland ADCT BioPharma as of June 30, 2023 and 2022, respectively. (in KUSD) Interest in joint venture January 1, 2023 31,152  Share of comprehensive loss in joint venture (2,830) June 30, 2023 28,322  January 1, 2022 41,236  Share of comprehensive loss in joint venture (4,419) June 30, 2022 36,817
Summary of financial information in join venture	The tables below provide summarized financial information for Overland ADCT BioPharma that is material to the Company. The following information reflects the amounts presented in the financial statements of Overland ADCT BioPharma and not the Company’s share of those amounts. (in KUSD) As of Summarized Balance Sheet June 30, 2023 December 31, 2022 Cash and cash equivalents 11,033  19,261  Prepaid and other current assets 218  2  Intangible assets 49,249  49,249  Total liabilities (2,493) (3,062) Net assets 58,007  65,450  Summarized Statement of Comprehensive Loss Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Loss from operations 3,021  4,576  5,528  9,367  Other expense (income) (1,457) (662) (1,183) (704) Other comprehensive loss (income) 908  —  1,431  —  Total comprehensive loss 2,472  3,914  5,776  8,663

v3.23.2

Leases (Tables)	6 Months Ended
	Jun. 30, 2023
Presentation of leases for lessee [abstract]
Schedule of quantitative information about right-of-use assets	The table below provides a rollforward of the Company's right-of-use assets as of June 30, 2023 and 2022, respectively. (in KUSD) Right-of-Use Assets Properties (Offices) Vehicles Total Cost January 1, 2023 9,311  134  9,445  Additions 4,818  —  4,818  Exchange difference 332  —  332  June 30, 2023 14,461  134  14,595  Accumulated depreciation January 1, 2023 (2,642) (83) (2,725) Depreciation charge (830) (16) (846) Exchange difference (53) —  (53) June 30, 2023 (3,525) (99) (3,624) Net book amount as of June 30, 2023 10,936  35  10,971  Cost January 1, 2022 9,005  134  9,139  Exchange difference (523) —  (523) June 30, 2022 8,482  134  8,616  Accumulated depreciation January 1, 2022 (1,925) (50) (1,975) Depreciation charge (589) (17) (606) Exchange difference 59  —  59  June 30, 2022 (2,455) (67) (2,522) Net book amount as of June 30, 2022 6,027  67  6,094
Schedule of quantitative information about lease liabilities	Depreciation of right-of-use assets have been charged to the following categories in the unaudited condensed consolidated interim statement of operations. Depreciation expense for S&M expenses was not material for any of the periods presented. Three months ended June 30, Six months ended June 30, (in KUSD) 2023 2022 2023 2022 R&D expenses 392  238  723  483  G&A expenses 61  61  123  123  453  299  846  606  The table below provides a rollforward of the Company's lease liabilities as of June 30, 2023 and 2022, respectively. (in KUSD) Lease liabilities Properties (Offices) Vehicles Total January 1, 2023 7,607  54  7,661  Additions 4,818  —  4,818  Cash outflow (including interest) (695) (19) (714) Interest 256  1  257  Exchange difference 370  2  372  June 30, 2023 12,356  38  12,394  January 1, 2022 7,898  125  8,023  Cash outflow (including interest) (593) (18) (611) Interest 100  1  101  Exchange difference (575) (39) (614) June 30, 2022 6,830  69  6,899  June 30, 2023 Lease liabilities (short-term) 1,606  26  1,632  Lease liabilities (long-term) 10,750  12  10,762  Total lease liabilities 12,356  38  12,394  June 30, 2022 Lease liabilities (short-term) 875  34  909  Lease liabilities (long-term) 5,955  35  5,990  Total lease liabilities 6,830  69  6,899

v3.23.2

Senior secured term loan facility and warrants (Tables)	6 Months Ended
	Jun. 30, 2023
Financial Instruments [Abstract]
Schedule of key inputs used for valuation	The Company used an independent valuation firm to assist in calculating the fair value of the warrant obligations, using the Black-Scholes option-pricing model. Key inputs for the valuation of the warrant obligations as of June 30, 2023 and December 31, 2022 were as follows: As of As of June 30, 2023 December 31, 2022 Exercise price in USD 8.30  8.30  Share price in USD 2.15  3.84  Risk-free interest rate 4.3  % 4.0  % Expected volatility 80  % 80  % Expected term (months) 49.5 months 55.5 months Dividend yield —  —  Black-Scholes value in USD 0.72  1.89  Key inputs for the valuations as of June 30, 2022 was as follows: Deerfield First Tranche As of June 30, 2022 Exercise price at 130% of the IPO price of 19.00, in USD 24.70  Forced conversion price, in USD 67.93  Share price in USD 7.95  Risk-free interest rate 3.0  % Expected volatility 86  % Expected term (months) 34.0 months Dividend yield —  Recovery rate 5  % Implied bond yield 12.0  % Deerfield Second Tranche As of June 30, 2022 Exercise price in USD 28.07  Forced conversion price, in USD 77.19  Share price in USD 7.95  Risk-free interest rate 3.0  % Expected volatility 86  % Expected term (months) 34.0 months Dividend yield —  Recovery rate 5  % Implied bond yield 12.0  %

v3.23.2

Convertible loans (Tables)	6 Months Ended
	Jun. 30, 2023
Financial Instruments [Abstract]
Schedule of Derivative Option and Convertible Loan	The following table summarizes the changes in fair value income of the embedded conversion option derivatives during the three and six months June 30, 2022: Three months ended June 30, Six months ended June 30, (in KUSD) 2022 2022 Deerfield First Tranche 8,860  18,378  Deerfield Second Tranche - after FDA approval 5,595  11,932  Total 14,455  30,310
Schedule of key inputs used for valuation	The Company used an independent valuation firm to assist in calculating the fair value of the warrant obligations, using the Black-Scholes option-pricing model. Key inputs for the valuation of the warrant obligations as of June 30, 2023 and December 31, 2022 were as follows: As of As of June 30, 2023 December 31, 2022 Exercise price in USD 8.30  8.30  Share price in USD 2.15  3.84  Risk-free interest rate 4.3  % 4.0  % Expected volatility 80  % 80  % Expected term (months) 49.5 months 55.5 months Dividend yield —  —  Black-Scholes value in USD 0.72  1.89  Key inputs for the valuations as of June 30, 2022 was as follows: Deerfield First Tranche As of June 30, 2022 Exercise price at 130% of the IPO price of 19.00, in USD 24.70  Forced conversion price, in USD 67.93  Share price in USD 7.95  Risk-free interest rate 3.0  % Expected volatility 86  % Expected term (months) 34.0 months Dividend yield —  Recovery rate 5  % Implied bond yield 12.0  % Deerfield Second Tranche As of June 30, 2022 Exercise price in USD 28.07  Forced conversion price, in USD 77.19  Share price in USD 7.95  Risk-free interest rate 3.0  % Expected volatility 86  % Expected term (months) 34.0 months Dividend yield —  Recovery rate 5  % Implied bond yield 12.0  %
Schedule of borrowings	The following table summarizes the interest expense recorded on the convertible loan for the three and six months ended June 30, 2022: Three months ended June 30, Six months ended June 30, (in KUSD) 2022 2022 Deerfield First Tranche 2,313  4,532  Deerfield Second Tranche 813  1,616  Total 3,126  6,148  The table below provides a rollforward of the Company’s debt obligation relating to the royalty purchase agreement. (in KUSD) January 1, 2022 225,477  Less: royalty payments 10,998  Plus: interest expense 23,200  Less: cumulative catch-up adjustment, Financial income 15,402  December 31, 2022 222,277  Plus: Additional proceeds from the sale of future royalties 75,000  Less: Transaction costs 1,898  Less: royalty payments 6,230  Plus: interest expense 11,575  Plus: cumulative catch-up adjustment, Financial expense 5,288  June 30, 2023 306,012

v3.23.2

Deerfield Warrants (Tables)	6 Months Ended
	Jun. 30, 2023
Subclassifications of assets, liabilities and equities [abstract]
Schedule of valuation inputs	Key inputs for the valuation of the warrant obligation as of June 30, 2023 were as follows: As of As of June 30, 2023 December 31, 2022 Exercise price in USD 24.70 and 28.07 24.70 and 28.07 Share price in USD 2.15  3.84  Risk-free interest rate 4.9  % 4.3  % Expected volatility 80  % 70  % Expected term (months) 22.7 months 28.7 months Dividend yield —  —  Black-Scholes value in USD 0.04 and 0.03 0.20 and 0.16

v3.23.2

Share-based compensation (Tables)	6 Months Ended
	Jun. 30, 2023
Share-based Payment Arrangements [Abstract]
Schedule of Shares Outstanding	The following table summarizes the share option awards outstanding as of June 30, 2023:   Average strike price per share in USD Number of awards Weighted average remaining life in years December 31, 2022 18.30  10,755,494  8.46 Granted 2.47  3,140,641  8.71 Option Exchange - Granted 2.06  898,585  8.71 Forfeited 16.14  (1,303,983) N/A Option Exchange - Forfeited 22.55  (2,197,458) N/A June 30, 2023 11.93  11,293,279  8.31
Schedule of Fair Value Assumption For Options Granted	The fair values of the options granted under the Equity Incentive Plan 2019 during the three and six months ended June 30, 2023 were determined on the date of the grant using the following assumptions:   Three Months Ended Three Months Ended Six Months Ended Six Months Ended   June 30, 2023 June 30, 2022 June 30, 2023 June 30, 2022 Share price, in USD 1.96 - 2.38 6.55 - 14.83 1.96 - 5.45 6.55 - 19.69 Strike price, in USD 1.96 - 2.38 6.55 - 14.83 1.96 - 5.45 6.55 - 19.69 Expected volatility, in % 75% to 80% 70% to 75% 75% to 80% 70% to 75% Award life, in years 6.08 6.08 6.08 6.08 Expected dividends — — — — Risk-free interest rate, in % 3.56% - 4.02% 2.49% - 3.05% 3.39% - 4.13% 1.46% - 3.05%
Schedule of Other Equity Instruments Outstanding	Number of awards   Weighted average grant date fair value December 31, 2022 1,585,877  13.26  Granted 979,680  2.13  Vested (1,269,106) 8.73  Forfeited (187,552) 9.25  June 30, 2023 1,108,899  9.30
Schedule of Share-based Compensation Reserve	The movement in the Share-based Compensation Reserves (included in Other reserves within equity) is as follows: Three months ended Six months ended (in KUSD) June 30, 2023 June 30, 2022 June 30, 2023 June 30, 2022 Equity Incentive Plan 2019 - Share Options (715) 8,450  4,066  18,965  Equity Incentive Plan 2019 - RSUs 1,725  5,368  4,921  8,763  ESPP Expense 108  —  205  —  Tax and social charge deductions - Incentive Plan 2019 —  —  —  (512) Total 1,118  13,818  9,192  27,216

v3.23.2

Related parties (Tables)	6 Months Ended
	Jun. 30, 2023
Related Party [Abstract]
Key Management Compensation	The compensation of key management is shown below: Three months ended June 30, Six months ended June 30, (in KUSD) 2023 2022 2023   2022 Salaries and other short-term employee costs 2,587  2,062  6,218  4,206  Pension costs 36  71  231  204  Share-based compensation expense 3,068  6,875  6,712  12,449  Other compensation 33  8  71  18  Total 5,724  9,016  13,232  16,877

v3.23.2

Loss per share (Tables)	6 Months Ended
	Jun. 30, 2023
Earnings per share [abstract]
Schedule of loss per share and potentially dilutive securities	Three Months Ended June 30,   Six Months Ended June 30, (in KUSD, except per share amounts) 2023   2022   2023   2022 Loss attributable to owners (47,117) (64,374) (106,543) (81,035) Weighted average number of shares outstanding 81,471,127  76,911,713  81,140,287  76,866,968  Basic and diluted loss per share (0.58) (0.84) (1.31) (1.05) For the three and six months ended June 30, 2023, basic and diluted loss per share are calculated on the weighted average number of shares issued and outstanding and exclude shares to be issued under the Equity Incentive Plan 2019, 2022 ESPP and the Company’s warrant agreements, as the effect of including those shares would be anti-dilutive. For the three and six months ended June 30, 2022, basic and diluted loss per share are calculated on the weighted average number of shares issued and outstanding and exclude shares to be issued under the 2019 Equity Incentive Plan and the conversion of the principal amount of the convertible loans into the Company’s common shares as the effect of including those shares would be anti-dilutive. See note 16, “Share-based compensation expense,” note 13, “Senior secured term loan facility and warrants,” note 15, “Deerfield warrants” and note 14, “Convertible loans” for further information. Potentially dilutive securities that were not included in the diluted per share calculations because the effect of including them would be anti-dilutive were as follows: Six Months Ended June 30, 2023   2022 Equity Incentive Plan 2019 - Share Options 11,293,279  8,066,461  Equity Incentive Plan 2019 - RSUs 1,108,899  1,354,432  Conversion of the principal amount of convertible loans into the Company’s common shares —  4,412,840  Outstanding warrants 4,940,135  —  17,342,313  13,833,733

v3.23.2

Corporate information (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($) subsidiary	Dec. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Disclosure of detailed information about borrowings [line items]
Number of subsidiaries | subsidiary	3
Cash and cash equivalents	$ 347,510	$ 326,441	$ 376,778	$ 466,544
Senior Secured Term Loans
Disclosure of detailed information about borrowings [line items]
Cash and cash equivalents, minimum quarterly balance	$ 60,000

v3.23.2

Basis of preparation - Schedule of Foreign currency exchange rate (Details) - $ / £	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Corporate information and statement of IFRS compliance [abstract]
Closing foreign exchange rate	1.26627	1.21470
Average foreign exchange rate	1.24535	1.20080

v3.23.2

Financial risk management (Details) - Interest rate risk - Senior Secured Term Loan Facility $ in Thousands	Jun. 30, 2023 USD ($)
Disclosure of detailed information about financial instruments [line items]
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, increase on derivative values	$ 910
Sensitivity analysis for types of interest rate risk, reasonably possible change in risk variable, decrease on derivative values	$ 910

v3.23.2

Revenue recognition - Schedule Of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disclosure of disaggregation of revenue from contracts with customers [line items]
Total revenue	$ 19,283	$ 17,291	$ 38,275	$ 63,789
U.S.
Disclosure of disaggregation of revenue from contracts with customers [line items]
Total revenue	19,197	17,291	38,150	33,789
EMEA(1)
Disclosure of disaggregation of revenue from contracts with customers [line items]
Total revenue	86	0	125	0
Japan
Disclosure of disaggregation of revenue from contracts with customers [line items]
Total revenue	0	0	0	30,000
Product revenues, net
Disclosure of disaggregation of revenue from contracts with customers [line items]
Total revenue	19,197	17,291	38,150	33,789
License revenues and royalties
Disclosure of disaggregation of revenue from contracts with customers [line items]
Total revenue	0	0	0	30,000
Royalty Revenue
Disclosure of disaggregation of revenue from contracts with customers [line items]
Total revenue	$ 86	$ 0	$ 125	$ 0

v3.23.2

Revenue recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Revenue From Contracts With Customers [Abstract]
Sales adjustment, beginning balance	$ 5,734	$ 3,464	$ 5,734	$ 3,464	$ 4,362	$ 3,746	$ 4,126	$ 2,590
GTN Sales Adjustment, Provision	5,783	3,206	11,399	6,697
GTN Sales Adjustment, Provision, Prior Period Sales	(229)	87	(877)	(105)
GTN Sales Adjustment, Credits And Payments	(4,182)	(3,955)	(8,534)	(5,718)
Sales adjustment, ending balance	5,734	$ 3,464	5,734	$ 3,464
Accounts receivable, net	1,677		1,677			2,151
Other current liabilities	$ 4,057		$ 4,057			$ 1,595

v3.23.2

Revenue recognition - Narrative (Details) - USD ($) $ in Thousands		1 Months Ended		3 Months Ended		6 Months Ended
	Jan. 18, 2022	Jul. 31, 2022	Jan. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disclosure of disaggregation of revenue from contracts with customers [line items]
Total revenue				$ 19,283	$ 17,291	$ 38,275	$ 63,789
Proceeds From License Agreement	$ 30,000
License Agreement, Milestone Payments	$ 205,000
License Agreement
Disclosure of disaggregation of revenue from contracts with customers [line items]
Proceeds From License Agreement		$ 55,000
License Agreement, Milestone Payments		$ 382,500
Application Approval
Disclosure of disaggregation of revenue from contracts with customers [line items]
License Agreement, Milestone Payments			$ 50,000

v3.23.2

Segment information (Details)	6 Months Ended
	Jun. 30, 2023 segment
Operating Segments [Abstract]
Number of business segments	1

v3.23.2

Operating expense - Schedule of Expenses by Nature (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disclosure Of Detailed Information About Expenses By Nature [Line Items]
Cost of product sales	$ 1,319	$ 2,266	$ 1,909	$ 2,795
Research and development expense	31,944	48,537	71,424	97,489
Sales and marketing expense	14,456	17,659	29,807	36,029
General and administrative expense	11,353	18,240	26,496	37,251
Operating expense	59,072	86,702	129,636	173,564
External costs
Disclosure Of Detailed Information About Expenses By Nature [Line Items]
Research and development expense	17,947	30,175	39,601	59,343
Sales and marketing expense	8,329	9,259	15,689	18,170
General and administrative expense	4,881	5,880	9,419	13,519
Employee expense
Disclosure Of Detailed Information About Expenses By Nature [Line Items]
Research and development expense	13,997	18,362	31,823	38,146
Sales and marketing expense	6,127	8,400	14,118	17,859
General and administrative expense	$ 6,472	$ 12,360	$ 17,077	$ 23,732

v3.23.2

Other income (expense) - Schedule of financial income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Analysis of income and expense [abstract]
Interest income	$ 2,372	$ 16	$ 4,547	$ 36
Cumulative catch-up adjustment, deferred royalty obligation	0	0	0	18,288
Financial income	$ 2,372	$ 16	$ 4,547	$ 18,324

v3.23.2

Other income (expense) - Schedule of financial expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disclosure of attribution of expenses by nature to their function [line items]
Cumulative catch-up adjustment, deferred royalty obligation	$ 5,417	$ 0	$ 5,288	$ 0
Deferred royalty obligation interest expense	5,829	5,545	11,575	11,687
Interest expense on lease obligations	131	130	262	183
Financial expense	15,857	8,801	26,145	18,018
Senior Secured Term Loan Facility
Disclosure of attribution of expenses by nature to their function [line items]
Interest expense on debt instruments issued	4,480	0	9,020	0
Convertible Loans
Disclosure of attribution of expenses by nature to their function [line items]
Interest expense on debt instruments issued	$ 0	$ 3,126	$ 0	$ 6,148

v3.23.2

Other income (expense) - Schedule of Other Income (Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disclosure of attribution of expenses by nature to their function [line items]
Convertible loans, derivatives, change in fair value income	$ 0	$ 14,455	$ 0	$ 30,310
Share of results with joint venture	(767)	(1,917)	(2,130)	(4,419)
Exchange differences gain (loss)	18	223	(34)	304
R&D tax credit	315	114	455	122
Non-operating (expense) income	(453)	12,875	(456)	26,317
Facility Agreement with Deerfield Partners, L.P.
Disclosure of attribution of expenses by nature to their function [line items]
Deerfield warrant obligation, change in fair value income	$ 20	0	$ 636	0
Senior Secured Term Loan Facility
Disclosure of attribution of expenses by nature to their function [line items]
Deerfield warrant obligation, change in fair value income		$ 0		$ 0

v3.23.2

Other income (expense) - Narrative (Details) - USD ($) $ in Millions	Aug. 15, 2022	Jun. 30, 2023	May 19, 2020	Apr. 24, 2020
Disclosure of detailed information about borrowings [line items]
Exchange Of Convertible Notes For Warrants	$ 115.0
Convertible Notes, Value Converted	$ 117.3
Warrants, Tranche One
Disclosure of detailed information about borrowings [line items]
Convertible Notes, Shares Converted	4,412,840
Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Borrowings			$ 65.0	$ 65.0
Facility Agreement With Deerfield Partners, L.P., Tranche Two
Disclosure of detailed information about borrowings [line items]
Borrowings				50.0
Borrowings, maximum borrowing capacity				50.0
Facility Agreement with Deerfield Partners, L.P.
Disclosure of detailed information about borrowings [line items]
Borrowings		$ 120.0
Borrowings, maximum borrowing capacity				$ 115.0

v3.23.2

Inventory (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Inventory [Abstract]
Current work in progress	$ 19,015	$ 18,165
Current finished goods	413	399
Inventories	$ 19,428	$ 18,564

v3.23.2

Inventory - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2022
ZYNLONTA For R&D
Disclosure Of Detailed Information About Expenses By Nature [Line Items]
Adjustments for impairment loss (reversal of impairment loss) recognised in profit or loss, inventories	$ 436	$ 75

v3.23.2

Intangible assets - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Disclosure of detailed information about intangible assets [line items]
Impairment of intangible assets	$ 743	$ 0
In-Human Clinical Study | Milestone Payment
Disclosure of detailed information about intangible assets [line items]
Additions		500
In-Vivo Efficacy studies | Milestone Payment
Disclosure of detailed information about intangible assets [line items]
Additions		$ 195
Licenses
Disclosure of detailed information about intangible assets [line items]
Impairment of intangible assets	$ 743

v3.23.2

Intangible assets - Rollforward of Intangible Assets (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Disclosure of detailed information about intangible assets [line items]
Beginning balance	$ 14,360
Ending balance	13,536	$ 14,575
Impairment of intangible assets	743	0
Cost
Disclosure of detailed information about intangible assets [line items]
Beginning balance	15,964	14,844
Additions	20	1,055
Exchange differences	3	(7)
Ending balance	15,987	15,892
Accumulated amortization
Disclosure of detailed information about intangible assets [line items]
Beginning balance	(1,604)	(1,262)
Exchange differences	1	2
Amortisation, intangible assets other than goodwill	(103)	(57)
Ending balance	(2,451)	(1,317)
Impairment of intangible assets	(743)
Licenses
Disclosure of detailed information about intangible assets [line items]
Ending balance	11,642	12,611
Impairment of intangible assets	743
Licenses | Cost
Disclosure of detailed information about intangible assets [line items]
Beginning balance	13,680	12,985
Additions	0	695
Exchange differences	0	0
Ending balance	13,680	13,680
Licenses | Accumulated amortization
Disclosure of detailed information about intangible assets [line items]
Beginning balance	(1,295)	(1,069)
Exchange differences	0	0
Amortisation, intangible assets other than goodwill	0	0
Ending balance	(2,038)	(1,069)
Impairment of intangible assets	(743)
Internal development costs
Disclosure of detailed information about intangible assets [line items]
Ending balance	0	894
Internal development costs | Cost
Disclosure of detailed information about intangible assets [line items]
Beginning balance	0	631
Additions	0	263
Exchange differences	0	0
Ending balance	0	894
Internal development costs | Accumulated amortization
Disclosure of detailed information about intangible assets [line items]
Beginning balance	0	0
Exchange differences	0
Amortisation, intangible assets other than goodwill	0	0
Ending balance	0	0
Impairment of intangible assets	0
Internal development costs
Disclosure of detailed information about intangible assets [line items]
Ending balance	916	0
Internal development costs | Cost
Disclosure of detailed information about intangible assets [line items]
Beginning balance	954	0
Additions	0	0
Exchange differences	0	0
Ending balance	954	0
Internal development costs | Accumulated amortization
Disclosure of detailed information about intangible assets [line items]
Beginning balance	0	0
Exchange differences		0
Amortisation, intangible assets other than goodwill	(38)	0
Ending balance	(38)	0
Impairment of intangible assets	0
Licenses
Disclosure of detailed information about intangible assets [line items]
Ending balance	889	965
Licenses | Cost
Disclosure of detailed information about intangible assets [line items]
Beginning balance	1,052	1,052
Additions	0	0
Exchange differences	0	0
Ending balance	1,052	1,052
Licenses | Accumulated amortization
Disclosure of detailed information about intangible assets [line items]
Beginning balance	(125)	(50)
Exchange differences	0	0
Amortisation, intangible assets other than goodwill	(38)	(37)
Ending balance	(163)	(87)
Impairment of intangible assets	0
Software
Disclosure of detailed information about intangible assets [line items]
Ending balance	89	105
Software | Cost
Disclosure of detailed information about intangible assets [line items]
Beginning balance	278	176
Additions	20	97
Exchange differences	3	(7)
Ending balance	301	266
Software | Accumulated amortization
Disclosure of detailed information about intangible assets [line items]
Beginning balance	(184)	(143)
Exchange differences	1	2
Amortisation, intangible assets other than goodwill	(27)	(20)
Ending balance	(212)	$ (161)
Impairment of intangible assets	$ 0

v3.23.2

Interest in joint venture - Narrative (Details) $ in Millions		6 Months Ended
	Dec. 14, 2020 product	Jun. 30, 2023 USD ($)
Disclosure of joint ventures [line items]
Deferred Gain On Investment In Joint Venture | $		$ 23.5
Overland ADCT BioPharma
Disclosure of joint ventures [line items]
Number of product candidates developed and commercialized in joint venture	3
Number of products developed and commercialized in joint venture	1

v3.23.2

Interest in joint venture - Schedule of movement in interest in joint venture (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Disclosure of joint ventures [line items]
Beginning balance	$ 31,152
Ending balance	28,322
Overland ADCT BioPharma
Disclosure of joint ventures [line items]
Beginning balance	31,152	$ 41,236
Share of comprehensive loss in joint venture	(2,830)	(4,419)
Ending balance	$ 28,322	$ 36,817

v3.23.2

Interest in joint venture - Summary of financial information in joint venture (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Disclosure of joint ventures [line items]
Cash and cash equivalents	$ 347,510	$ 376,778	$ 347,510	$ 376,778	$ 326,441	$ 466,544
Intangible assets	13,536	14,575	13,536	14,575	14,360
Total liabilities	(515,891)		(515,891)		(440,441)
Operating expense	59,072	86,702	129,636	173,564
Net loss	(47,117)	(64,374)	(106,543)	(81,035)
Overland ADCT BioPharma
Disclosure of joint ventures [line items]
Cash and cash equivalents	11,033		11,033		19,261
Prepaid and other current assets	218		218		2
Intangible assets	49,249		49,249		49,249
Total liabilities	(2,493)		(2,493)		(3,062)
Net assets	58,007		58,007		$ 65,450
Operating expense	3,021	4,576	5,528	9,367
Other expense (income)	(1,457)	(662)	(1,183)	(704)
Other comprehensive loss (income)	908	0	1,431	0
Net loss	$ 2,472	$ 3,914	$ 5,776	$ 8,663

v3.23.2

Leases - Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Jan. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Presentation of leases for lessee [abstract]
Lease liabilities	$ 12,394	$ 7,600	$ 7,661	$ 6,899	$ 8,023

v3.23.2

Leases - Right-of-Use Assets and Accumulated Depreciation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			$ 6,720
Depreciation charge	$ (453)	$ (299)	(846)	$ (606)
Right-of-use asset, ending balance	10,971	6,094	10,971	6,094
Cost
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			9,445	9,139
Additions			4,818
Exchange difference			332	(523)
Right-of-use asset, ending balance	14,595	8,616	14,595	8,616
Accumulated amortization
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			(2,725)	(1,975)
Exchange difference			(53)	59
Depreciation charge			(846)	(606)
Right-of-use asset, ending balance	(3,624)	(2,522)	(3,624)	(2,522)
Properties (Offices)
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, ending balance	10,936	6,027	10,936	6,027
Properties (Offices) | Cost
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			9,311	9,005
Additions			4,818
Exchange difference			332	(523)
Right-of-use asset, ending balance	14,461	8,482	14,461	8,482
Properties (Offices) | Accumulated amortization
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			(2,642)	(1,925)
Exchange difference			(53)	59
Depreciation charge			(830)	(589)
Right-of-use asset, ending balance	(3,525)	(2,455)	(3,525)	(2,455)
Vehicles
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, ending balance	35	67	35	67
Vehicles | Cost
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			134	134
Additions			0
Exchange difference			0	0
Right-of-use asset, ending balance	134	134	134	134
Vehicles | Accumulated amortization
Disclosure of quantitative information about right-of-use assets [line items]
Right-of-use asset, beginning balance			(83)	(50)
Exchange difference			0	0
Depreciation charge			(16)	(17)
Right-of-use asset, ending balance	$ (99)	$ (67)	$ (99)	$ (67)

v3.23.2

Leases - Right-of-Use Asset Depreciation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disclosure of quantitative information about right-of-use assets [line items]
Depreciation, right-of-use assets	$ 453	$ 299	$ 846	$ 606
R&D expense
Disclosure of quantitative information about right-of-use assets [line items]
Depreciation, right-of-use assets	392	238	723	483
G&A expense
Disclosure of quantitative information about right-of-use assets [line items]
Depreciation, right-of-use assets	$ 61	$ 61	$ 123	$ 123

v3.23.2

Leases - Schedule of Lease Liabilities (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Disclosure Of Quantitative Information About Lease Liabilities [Line Items]
Beginning balance	$ 7,661	$ 8,023
Additions	4,818
Cash outflow (including interest)	(714)	(611)
Interest	257	101
Exchange difference	372	(614)
Ending balance	12,394	6,899
Lease liabilities, short-term	1,632	909	$ 1,097
Lease liabilities, long-term	10,762	5,990	$ 6,564
Properties (Offices)
Disclosure Of Quantitative Information About Lease Liabilities [Line Items]
Beginning balance	7,607	7,898
Additions	4,818
Cash outflow (including interest)	(695)	(593)
Interest	256	100
Exchange difference	370	(575)
Ending balance	12,356	6,830
Lease liabilities, short-term	1,606	875
Lease liabilities, long-term	10,750	5,955
Vehicles
Disclosure Of Quantitative Information About Lease Liabilities [Line Items]
Beginning balance	54	125
Additions	0
Cash outflow (including interest)	(19)	(18)
Interest	1	1
Exchange difference	2	(39)
Ending balance	38	69
Lease liabilities, short-term	26	34
Lease liabilities, long-term	$ 12	$ 35

v3.23.2

Senior secured term loan facility and warrants - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Senior Secured Term Loans
Disclosure of detailed information about borrowings [line items]
Borrowings	$ 111,200	$ 111,200
Borrowings, interest rate	1679.00%	1679.00%
Interest expense on borrowings	$ 4,480	$ 9,020
Cash and cash equivalents, minimum quarterly balance	60,000	60,000
Convertible loans, long-term	97,356	97,356	$ 97,240
Oak Tree And Owl Rock Warrant Obligations
Disclosure of detailed information about borrowings [line items]
Deerfield warrant obligation, change in fair value income	(39)	617
Warrant Obligation, Fair Value	$ 378	$ 378	$ 995

v3.23.2

Senior secured term loan facility and warrants - Valuation of Derivative (Details) - Oak Tree And Owl Rock Warrant Obligations - shares	Jun. 30, 2023	Dec. 31, 2022
Written put options (in USD per share)
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	8.30	8.30
Share Price (in USD per share)
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	2.15	3.84
Risk Free, Interest Rate
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	0.043	0.040
Expected Volatility
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	0.80	0.80
Expected Term
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	49.5	55.5
Dividend yield
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	0	0
Black-Scholes Value
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	0.72	1.89

v3.23.2

Convertible loans - Narrative (Details) - USD ($) $ in Millions	Aug. 15, 2022	Jun. 30, 2023	May 19, 2020	Apr. 24, 2020
Disclosure of detailed information about borrowings [line items]
Exchange Of Convertible Notes For Warrants	$ 115.0
Convertible Notes, Value Converted	117.3
Loss on extinguishment	$ (42.1)
Warrants, Tranche One
Disclosure of detailed information about borrowings [line items]
Convertible Notes, Shares Converted	4,412,840
Warrants, Tranche Two
Disclosure of detailed information about borrowings [line items]
Convertible Notes, Shares Converted	2,390,297
Facility Agreement with Deerfield Partners, L.P.
Disclosure of detailed information about borrowings [line items]
Borrowings		$ 120.0
Borrowings, maximum borrowing capacity				$ 115.0
Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Borrowings			$ 65.0	65.0
Facility Agreement With Deerfield Partners, L.P., Tranche Two
Disclosure of detailed information about borrowings [line items]
Borrowings				50.0
Borrowings, maximum borrowing capacity				$ 50.0
Senior Secured Term Loans
Disclosure of detailed information about borrowings [line items]
Borrowings		$ 111.2

v3.23.2

Convertible loans - Change in Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disclosure of detailed information about borrowings [line items]
Convertible loans, derivatives, change in fair value income	$ 0	$ 14,455	$ 0	$ 30,310
Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Convertible loans, derivatives, change in fair value income		8,860		18,378
Facility Agreement With Deerfield Partners, L.P., Tranche Two After FDA Approval
Disclosure of detailed information about borrowings [line items]
Convertible loans, derivatives, change in fair value income		$ 5,595		$ 11,932

v3.23.2

Convertible loans - Valuation of Derivative (Details)		6 Months Ended
	May 19, 2020 $ / shares	Jun. 30, 2023 period $ / shares
Initial Public Offering
Disclosure of detailed information about borrowings [line items]
Offering price per share (in USD per share)	$ 19.00
Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Conversion percentage		130.00%
Written put options (in USD per share) | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		24.70
Written put options (in USD per share) | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche Two
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		28.07
Forced Conversion Price (in USD per share) | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		67.93
Forced Conversion Price (in USD per share) | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche Two
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		77.19
Share Price (in USD per share) | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		7.95
Share Price (in USD per share) | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche Two
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		7.95
Risk Free, Interest Rate | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		0.030
Risk Free, Interest Rate | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche Two
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		0.030
Expected Volatility | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		0.86
Expected Volatility | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche Two
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		0.86
Expected Term | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations | period		34
Expected Term | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche Two
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations | period		34
Dividend yield | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		0
Dividend yield | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche Two
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		0
Recovery Rate [Member] | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		0.05
Recovery Rate [Member] | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche Two
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		0.05
Implied Bond Yield [Member] | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		0.120
Implied Bond Yield [Member] | Derivatives | Facility Agreement With Deerfield Partners, L.P., Tranche Two
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations		0.120

v3.23.2

Convertible loans - Interest Expense (Details) - Residual Loan - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Disclosure of detailed information about borrowings [line items]
Interest expense on borrowings	$ 3,126	$ 6,148
Facility Agreement With Deerfield Partners, L.P., Tranche One
Disclosure of detailed information about borrowings [line items]
Interest expense on borrowings	2,313	4,532
Facility Agreement With Deerfield Partners, L.P., Tranche Two
Disclosure of detailed information about borrowings [line items]
Interest expense on borrowings	$ 813	$ 1,616

v3.23.2

Deerfield Warrants - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
	Aug. 15, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Facility Agreement with Deerfield Partners, L.P.
Disclosure of detailed information about borrowings [line items]
Deerfield warrant obligation, change in fair value income		$ 20	$ 0	$ 636	$ 0
Warrant Obligation, Fair Value	$ 12,297	$ 157		$ 157		$ 793
Warrants, Tranche One
Disclosure of detailed information about borrowings [line items]
Convertible Notes, Shares Converted	4,412,840
Warrants, Tranche One, Price One
Disclosure of detailed information about borrowings [line items]
Convertible Notes, Shares Converted	2,631,578
Warrants, Shares Converted, Exercise Price	$ 24.70
Warrants, Tranche One, Price Two
Disclosure of detailed information about borrowings [line items]
Convertible Notes, Shares Converted	1,781,262
Warrants, Shares Converted, Exercise Price	$ 28.07

v3.23.2

Deerfield Warrants - Schedule of Valuation Inputs (Details) - Deerfield Warrants	Jun. 30, 2023 shares $ / shares period	Dec. 31, 2022 $ / shares shares period
Exercise Price | Minimum
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	24.70	24.70
Exercise Price | Maximum
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	28.07	28.07
Black-Scholes Value | Minimum
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations | shares	0.04	0.20
Black-Scholes Value | Maximum
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations | shares	0.03	0.16
Derivatives | Forced Conversion Price (in USD per share)
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	2.15	3.84
Derivatives | Share Price (in USD per share)
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	0.049	0.043
Derivatives | Risk Free, Interest Rate
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	0.80	0.70
Derivatives | Expected Volatility
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations	22.7	28.7
Derivatives | Expected Term
Disclosure of detailed information about borrowings [line items]
Key inputs for valuations | period	0	0

v3.23.2

Share-based compensation - Narrative (Details)			3 Months Ended		6 Months Ended
	Apr. 04, 2023 $ / shares shares	Mar. 22, 2021 shares	Jun. 30, 2023 USD ($) shares $ / shares	Jun. 30, 2022 USD ($) shares $ / shares	Jun. 30, 2023 USD ($) shares $ / shares	Jun. 30, 2022 USD ($) shares $ / shares	Dec. 31, 2022 shares	Nov. 30, 2019 shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized | $			$ 1,118,000	$ 13,818,000	$ 9,192,000	$ 27,216,000
Share-based compensation expense | $			$ 1,118,000	13,818,000	$ 9,192,000	27,216,000
Number of share options outstanding in share-based payment arrangement (in shares) | shares			11,293,279		11,293,279		10,755,494
Average strike price in USD per share, Option Exchange - Granted (in USD per share)					$ 2.06
Expected dividends | $			$ 0	$ 0	$ 0	$ 0
Number of awards, Option Exchange - Granted (in shares) | shares					898,585
Maximum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Strike price (in USD per share)			$ 2.38	$ 14.83	$ 5.45	$ 19.69
Expected volatility, in %			80.00%	75.00%	80.00%	75.00%
Risk-free interest rate, in %			4.02%	3.05%	4.13%	3.05%
Minimum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Strike price (in USD per share)			$ 1.96	$ 6.55	$ 1.96	$ 6.55
Expected volatility, in %			75.00%	70.00%	75.00%	70.00%
Risk-free interest rate, in %			356.00%	2.49%	3.39%	1.46%
Share Options
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period					3 years
Share-based compensation expense | $			$ (715,000)	$ 8,450,000	$ 4,066,000	$ 18,965,000
Contractual term					10 years
Number of instruments granted in share-based payment arrangement | shares		2,026,341	1,010,000	13,818,000	8,987,000	27,728,000
Weighted-average grant-date fair value (in dollars per share)			$ 1.41
Awards vested and exercisable (in shares) | shares			3,765,502		3,765,502
Weighted average strike price, vested and exercisable (in dollars per share)					$ 23.97
Weighted average remaining life, vested and exercisable					6 years 8 months 15 days
Share Options | Tranche One
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting percentage					25.00%
Share Options | Tranche Two
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting percentage					25.00%
Share Options | Tranche Three
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting percentage					25.00%
Share Options | Tranche Four
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting percentage					25.00%
Restricted Share Units (RSU)
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period					3 years
Contractual term					10 years
Shares vested (in shares) | shares					1,269,106
Number of instruments granted in share-based payment arrangement | shares		538,175	1,725,000		4,921,000
Weighted average grant date fair value, granted (in USD per share)					$ 2.13
2019 Equity Incentive Plan
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of shares reserved for issue under options and contracts for sale of shares | shares			2,564,140		2,564,140			17,741,355
Share-based compensation expense | $					$ 154,088,000
Annual Equity Award | Restricted Share Units (RSU)
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average grant date fair value, granted (in USD per share)					$ 1.99
Equity Exchange Program
Disclosure of terms and conditions of share-based payment arrangement [line items]
Average strike price in USD per share, Option Exchange - Granted (in USD per share)	$ 2.06				$ 2.06
Expected dividends | $			$ 0
Number of awards, Option Exchange - Granted (in shares) | shares	900,000
Number Of Share Options Exchanged | shares	2,200,000
Equity Exchange Program | Maximum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expected volatility, in %			79.00%
Risk-free interest rate, in %			3.31%
Exercise price of share options granted in share-based payment arrangement	$ 48.77
Equity Exchange Program | Minimum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expected volatility, in %			77.00%
Risk-free interest rate, in %			3.29%
Exercise price of share options granted in share-based payment arrangement	$ 8.12

v3.23.2

Share-based compensation - Schedule of Number of Awards Outstanding and Weighted Average Strike Price (Details)	3 Months Ended	6 Months Ended
	Mar. 31, 2023 shares $ / shares	Jun. 30, 2023 shares $ / shares
Share-based Payment Arrangements [Abstract]
Average strike price in USD per share, At beginning of the year (in USD per share) | $ / shares	$ 18.30	$ 18.30
Average strike price in USD per share, Granted (in USD per share) | $ / shares		2.47
Average strike price in USD per share, Option Exchange - Granted (in USD per share) | $ / shares		2.06
Average strike price in USD per share, Forfeited (in USD per share) | $ / shares		16.14
Average strike price in USD per share, Option Exchange - Forfeited (in USD per share) | $ / shares		22.55
Average strike price in USD per share, At end of the year (in USD per share) | $ / shares		$ 11.93
Number of awards, At beginning of the year (in shares) | shares	10,755,494	10,755,494
Number of awards, Granted (in shares) | shares		3,140,641
Number of awards, Option Exchange - Granted (in shares) | shares		898,585
Number of awards, Forfeited (in shares) | shares		(1,303,983)
Number of awards, Option Exchange - Forfeited (in shares) | shares		(2,197,458)
Number of awards, At end of the year (in shares) | shares		11,293,279
Weighted average remaining contractual life of outstanding share options	8 years 5 months 15 days	8 years 3 months 21 days
Weighted average remaining contractual life of granted share options		8 years 8 months 15 days
Weighted Average Remaining Contractual Life Of Option Exchange, Granted		8 years 8 months 15 days

v3.23.2

Share-based compensation expense - Schedule of Fair Value Assumptions For Options Granted (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($) shares $ / shares	Jun. 30, 2022 USD ($) shares $ / shares	Jun. 30, 2023 USD ($) shares $ / shares	Jun. 30, 2022 USD ($) shares $ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Award life, in years | shares		6.08		6.08
Expected dividends | $	$ 0	$ 0	$ 0	$ 0
Minimum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average share price (in USD per share)	$ 1.96	$ 6.55	$ 1.96	$ 6.55
Strike price (in USD per share)	$ 1.96	$ 6.55	$ 1.96	$ 6.55
Expected volatility, in %	75.00%	70.00%	75.00%	70.00%
Award life, in years | shares	6.08		6.08
Risk-free interest rate, in %	356.00%	2.49%	3.39%	1.46%
Maximum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average share price (in USD per share)	$ 2.38	$ 14.83	$ 5.45	$ 19.69
Strike price (in USD per share)	$ 2.38	$ 14.83	$ 5.45	$ 19.69
Expected volatility, in %	80.00%	75.00%	80.00%	75.00%
Risk-free interest rate, in %	4.02%	3.05%	4.13%	3.05%

v3.23.2

Share-based compensation - Schedule of Other Equity Instruments Outstanding (Details) - Restricted Share Units (RSU)	6 Months Ended
	Jun. 30, 2023 shares $ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of awards, beginning of period (in shares) | shares	1,585,877
Number of awards, granted (in shares) | shares	979,680
Number of awards, vested (in shares) | shares	(1,269,106)
Number of awards, forfeited (in shares) | shares	(187,552)
Number of awards, end of period (in shares) | shares	1,108,899
Weighted average grant date fair value, beginning balance (in USD per share) | $ / shares	$ 13.26
Weighted average grant date fair value, granted (in USD per share) | $ / shares	2.13
Weighted average grant date fair value, vested (in dollars per share) | $ / shares	8.73
Weighted average grant date fair value, forfeited (in dollars per share) | $ / shares	9.25
Weighted average grant date fair value, ending balance (in USD per share) | $ / shares	$ 9.30

v3.23.2

Share-based compensation - Schedule of Share-based Compensation Reserve (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expense recognized	$ 1,118	$ 13,818	$ 9,192	$ 27,216
2019 Equity Incentive Plan
Disclosure of terms and conditions of share-based payment arrangement [line items]
Tax expense from share-based payment transactions with employees	0	0	0	(512)
2019 Equity Incentive Plan | Share Options
Disclosure of terms and conditions of share-based payment arrangement [line items]
Increase in reserve of share-based payments	(715)	8,450	4,066	18,965
2019 Equity Incentive Plan | Restricted Stock Units
Disclosure of terms and conditions of share-based payment arrangement [line items]
Increase in reserve of share-based payments	1,725	5,368	4,921	8,763
ESPP Expense
Disclosure of terms and conditions of share-based payment arrangement [line items]
Increase in reserve of share-based payments	$ 108	$ 0	$ 205	$ 0

v3.23.2

Deferred royalty obligation (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Mar. 31, 2022	Jun. 30, 2023	Dec. 31, 2022	Dec. 31, 2021	Aug. 25, 2021
Deferred Royalty Obligation [Abstract]
Royalty Purchase Agreement							$ 325,000,000
Proceeds From Royalty Purchase Agreement, Gross			$ 225,000,000
Royalty Purchase Additional Proceeds Eligibility		$ 75,000,000
Royalty Purchase Agreement, Effective Interest Rate				10.00%
Deferred Royalty Obligation	$ 306,012,000			$ 306,012,000	$ 222,277,000	$ 225,477,000
Less: royalty payments	6,230,000	10,998,000
Plus: Additional proceeds from the sale of future royalties				75,000,000
Less: Transaction costs				$ 1,898,000
Plus: interest expense	11,575,000	23,200,000
Less: cumulative catch-up adjustment, Financial income	$ 5,288,000	$ 15,402,000

v3.23.2

Related parties - Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) subsidiary	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Auven Therapeutics Holdings, L.P.
Disclosure of transactions between related parties [line items]
Number of subsidiaries provide services to | subsidiary			3
Overland ADCT BioPharma
Disclosure of transactions between related parties [line items]
Services provided to, related party transactions	$ 1,244	$ 876		$ 876
Amounts receivable, related party transactions	$ 1,482		$ 1,482		$ 805

v3.23.2

Related parties - Schedule of Key Management Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Related Party [Abstract]
Salaries and other short-term employee costs	$ 2,587	$ 2,062	$ 6,218	$ 4,206
Pension costs	36	71	231	204
Share-based compensation expense	3,068	6,875	6,712	12,449
Other compensation	33	8	71	18
Key management compensation	$ 5,724	$ 9,016	$ 13,232	$ 16,877

v3.23.2

Loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Earnings per share [abstract]
Net loss	$ (47,117)	$ (64,374)	$ (106,543)	$ (81,035)
Weighted average number of ordinary shares outstanding	81,471,127	76,911,713	81,140,287	76,866,968
Net loss per share, basic (in USD per share)	$ (0.58)	$ (0.84)	$ (1.31)	$ (1.05)
Net loss per share, diluted (in dollars per share)	$ (0.58)	$ (0.84)	$ (1.31)	$ (1.05)

v3.23.2

Loss per share -Schedule of Potentially Dilutive Securities (Details) - shares	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Earnings per share [line items]
Potentially dilutive securities	17,342,313	13,833,733
Equity Incentive Plan 2019 - Share Options
Earnings per share [line items]
Potentially dilutive securities	11,293,279	8,066,461
Equity Incentive Plan 2019 - RSUs
Earnings per share [line items]
Potentially dilutive securities	1,108,899	1,354,432
Conversion of the principal amount of convertible loans into the Company’s common shares
Earnings per share [line items]
Potentially dilutive securities	0	4,412,840
Outstanding Warrants
Earnings per share [line items]
Potentially dilutive securities	4,940,135	0

v3.23.2

Label	Element	Value
Capital Expenditures, Incurred But Not Yet Paid, Total	adc_CapitalExpendituresIncurredButNotYetPaidTotal	$ 114,000

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