periods were driven primarily by lower headcount. The decrease for the nine-month period was partially offset by the net $6.8 million charge in the first quarter of 2024 associated with the full write-off of the outlicense intangible asset and associated release of the CVR liability related to NZV930, obtained in the Surface Oncology, Inc. acquisition.
Interest expense was $5.4 million and $10.3 million during the three months ended September 30, 2024 and 2023, respectively, and $21.8 million and $29.9 million during the nine months ended September 30, 2024 and 2023, respectively. The declines in both periods were primarily due to prepaying $175.0 million of the principal amount due under the 2027 Term Loans on April 1, 2024 and the remaining $75.0 million principal amount on May 8, 2024, partially offset by interest on the senior secured term loan facility of up to $38.7 million and the revenue participation right purchase and sale agreement, both commencing May 8, 2024.
Gain on sale transactions, net was $176.6 million for the nine months ended September 30, 2024 and included a $153.8 million gain on the divestiture of our CIMERLI ophthalmology franchise, which closed during the first quarter of 2024, and a $22.9 million gain on the divestiture of our YUSIMRY immunology franchise, which closed during the second quarter of 2024. There was no gain on sale transactions in the nine months ended September 30, 2023.
Net loss for the third quarter of 2024 was $10.8 million, or $(0.09) per share on a diluted basis, compared to a net loss of $39.6 million, or $(0.41) per share on a diluted basis for the same period in 2023. Net income for the nine months ended September 30, 2024 was $79.2 million, or $0.65 per share on a diluted basis, compared to a net loss of $158.2 million, or $(1.79) per share on a diluted basis for nine months ended September 30, 2023.
Non-GAAP net loss for the third quarter of 2024 was $1.7 million, or $(0.01) per share on a diluted basis, compared to $26.9 million, or $(0.27) per share for the same period in 2023. Non-GAAP net loss for the nine months ended September 30, 2024 was $53.8 million, or $(0.47) per share on a diluted basis, compared to $117.3 million, or $(1.33) per share for the same period in 2023. See “Non-GAAP Financial Measures” below for a discussion on how Coherus calculates non-GAAP net loss and a reconciliation to the most directly comparable GAAP measures.
Cash, cash equivalents and investments in marketable securities were $97.7 million as of September 30, 2024, compared to $117.7 million as of December 31, 2023.
2024 R&D and SG&A Expense Guidance
Coherus projects combined R&D and SG&A expenses for 2024 to be in the range of $250 to $260 million. This guidance includes approximately $30 million of stock-based compensation expense and excludes the effects of acquisitions, collaborations, investments, divestitures including expenses incurred on behalf of and reimbursed by Sandoz Inc. and Hong Kong King-Friend Industrial Company Ltd. to satisfy Coherus’ obligations under the transition services agreements with those entities, restructuring, the exercise of rights or options related to collaboration programs, and any other transactions or circumstances not yet identified or quantified. This guidance is subject to a number of risks and uncertainties. See Forward-Looking Statements described in the section below.
Conference Call Information
When: Wednesday, November 6, 2024, starting at 5:00 p.m. Eastern Time
To access the conference call, please pre-register through the following link to receive dial-in information and a personal PIN to access the live call: https://register.vevent.com/register/BI6dfb4eba6e9a4322a716df863233a53f
Please dial in 15 minutes early to ensure a timely connection to the call.
Webcast: https://edge.media-server.com/mmc/p/fgk872yp
An archived webcast will be available on the “Investors” section of the Coherus website at https://investors.coherus.com/events-presentations.