MDSO Medidata Solutions Inc

[X] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).         
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES                                                                                   
OMB APPROVAL
OMB Number: 3235-0287
Estimated average burden
hours per response... 0.5                       
Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940                       

1. Name and Address of Reporting Person * Larsen Jill	2. Issuer Name and Ticker or Trading Symbol Medidata Solutions, Inc. [ MDSO ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director                    _____ 10% Owner __X__ Officer (give title below)    _____ Other (specify below) EVP, Human Resources
(Last)          (First)          (Middle) C/O MEDIDATA SOLUTIONS, INC., 350 HUDSON STREET, 9TH FLOOR	3. Date of Earliest Transaction (MM/DD/YYYY) 10/28/2019
(Street) NEW YORK, NY 10014 (City)        (State)        (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) _X _ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. Code (Instr. 8)		4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	10/28/2019 (1)		D		45555 (2)(3)	D	$92.25 (2)	0	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Options (right to buy)	$72.51	10/28/2019		D			17200 (4)	(5)	4/23/2028	Common Stock	17200.0 (4)	(4)	0	D
Restricted Stock Units (Performance-Related)	$0.0	10/28/2019		D			10343 (6)	(7)	(7)	Common Stock	10343.0	(6)	0	D
Restricted Stock Units (Performance Related)	$0.0	10/28/2019		D			19954 (6)	(8)	(8)	Common Stock	19954.0	(6)	0	D

Explanation of Responses:
(1)	On October 28, 2019, pursuant to the Agreement and Plan of Merger, dated as of June 11, 2019, by and among Dassault Systemes SE ("DS"), Dassault Systemes Americas Corp., a Delaware corporation ("Parent"), 3DS Acquisition 6 Corp., a Delaware corporation and a wholly-owned subsidiary of Parent ("Merger Sub"), and Medidata Solutions, Inc., a Delaware corporation (the "Issuer"), Merger Sub merged with and into the Issuer, with the Issuer surviving as a wholly-owned subsidiary of Parent and an indirect wholly-owned subsidiary of DS (the "Merger"). Pursuant to the separation agreement by and between the reporting person and the Issuer, dated October 25, 2019, each of the reporting person's shares of restricted stock will be deemed a Non-Employee RSA under the terms of the Merger Agreement.
(2)	Disposed of pursuant to the Merger Agreement and by virtue of the Merger, in which each share of Medidata common stock, par value $0.01 per share ("Issuer Common Stock"), issued and outstanding immediately prior to the completion of the Merger (other than restricted share awards held by continuing employees) was converted into the right to receive $92.25 in cash and without interest (the "Merger Consideration"). Such number of shares includes shares issued to the reporting person upon accelerated vesting of the reporting person's RSAs and Issuer PBRSUs (referred to below) immediately prior to the effective time of the Merger.
(3)	Included are 174 shares which were purchased pursuant to the terms of the Medidata Solutions, Inc. Employee Stock Purchase Plan on June 30, 2019.
(4)	Pursuant to the Merger Agreement and by virtue of the Merger, each option to purchase Issuer Common Stock will be cancelled and converted into the right to receive an amount in cash (without interest and subject to deduction for any required withholding tax) equal to the product of (1) the total number of shares of Issuer Common Stock then covered by such option multiplied by (2) the excess, if any, of $92.25 per share over the exercise price per share under such option.
(5)	The options vested as to 25% of the shares on April 23, 2019 and 1/36th of the remaining options will become exercisable each month thereafter for the next 36 months.
(6)	Pursuant to the separation agreement by and between the reporting person and the Issuer, dated October 25, 2019, each of the reporting person's performance-based restricted stock units will be deemed a Non-Employee PSU under the terms of the Merger Agreement and will be cancelled and converted into the right to receive an amount in cash equal to the product of (1) the total number of shares of Issuer Common Stock then covered by such PSU based on the attainment of the applicable performance metrics as determined by the issuer's Compensation committee multiplied by (2) $92.25 per share.
(7)	Award of PBRSUs granted under the 2017 LTIP on April 23, 2018. The number of PBRSUs represented a target amount. Each PBRSU represented a contingent right to receive 0-200% of that target number of shares of the issuer's common stock, (i) 50% based on the issuer's TSR as compared to the TSR of companies in the Russell 2000 Index for the three years ending December 31, 2020, and (ii) 50% based on the Company's GAAP Net Income attainment for the three years ending December 31, 2020. The shares would have vested immediately upon being earned.
(8)	Award of PBRSUs granted under the 2017 LTIP on February 12, 2019. The number of PBRSUs represented a target amount. Each PBRSU represented a contingent right to receive 0-225% of that target number of shares of the issuer's common stock, (i) 50% based on the issuer's TSR as compared to the TSR of companies in the Russell 2000 Index for the three years ending December 31, 2021, and (ii) 50% based on the Company's revenue attainment for the three years ending December 31, 2021. The shares would have vested immediately upon being earned.

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Larsen Jill C/O MEDIDATA SOLUTIONS, INC. 350 HUDSON STREET, 9TH FLOOR NEW YORK, NY 10014			EVP, Human Resources

Signatures
/s/ Michael I. Otner, Attorney-in-Fact		10/28/2019
**Signature of Reporting Person		Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note:	File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.