[Form 4] Blueprint Medicines Corporation Insider Trading Activity

Rhea-AI Filing Summary

Blueprint Medicines (BPMC) – Form 4 key points

Director Alexis Borisy reported the full disposition of his equity on 17 Jul 2025, the date Sanofi’s acquisition of Blueprint closed. Each share of common stock was exchanged for $129.00 cash plus one contingent value right (CVR) under the previously announced Merger Agreement. Table I records the tender of 74,160 shares (Code “U”), leaving 0 shares owned after the transaction. Table II shows cancellation of 46,545 stock options struck between $50.64 and $106.14; options became fully vested and converted into the right to receive the cash spread versus strike price plus one CVR per optioned share.

All restricted stock units were likewise canceled for the same consideration. As a result, Borisy now holds no direct or indirect interest in Blueprint securities, and Blueprint has become an indirect wholly owned subsidiary of Sanofi. The filing is administrative, confirming completion of the takeover rather than signaling new operational or valuation information.

Insights

M&A Specialist

TL;DR: Filing confirms Sanofi takeover closed; insider equity cashed out at $129 + CVR, leaving no residual float.

This Form 4 is a procedural disclosure documenting the cleanup of insider positions when a target company is absorbed. The cash-plus-CVR structure, already disclosed at deal announcement, is reaffirmed. No new economic terms emerge; investors have already priced the acquisition. Impact on remaining public holders is zero because shares are converted and Blueprint will soon be delisted. The transaction also triggers automatic vesting of equity awards, a standard feature in change-of-control clauses, and eliminates potential overhang from insider options.

Portfolio Manager

TL;DR: Insider exit is mandatory under merger; neutral for valuation as price locked at $129 cash plus CVR.

From a portfolio standpoint, the Form 4 does not alter risk/return. Holders will either have tendered or be cashed out; upside now rests solely on CVR milestones, which lie outside typical equity mandates. Position sizing and liquidity considerations end here because BPMC equity ceases trading post-close. The absence of remaining insider holdings confirms complete integration into Sanofi and removes concerns about residual minority interests.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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X

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

Rossi Christina

(Last) (First) (Middle)

C/O BLUEPRINT MEDICINES CORPORATION

45 SIDNEY STREET

(Street)

CAMBRIDGE MA 02139

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Blueprint Medicines Corp [ BPMC ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Operating Officer

3. Date of Earliest Transaction (Month/Day/Year)
07/17/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

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. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction 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	07/17/2025		A(1)(2)		39,456	A	(3)	103,002	D
Common Stock	07/17/2025		D(1)(2)		82,374	D	(3)(4)	20,628	D
Common Stock	07/17/2025		U(1)(2)		20,628	D	(5)	0	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction 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 (Month/Day/Year)		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: 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 Option (Right to Buy)	$65.75	07/17/2025		D(1)(2)			80,000	(6)	(6)	Common Stock	80,000	(6)	0	D
Stock Option (Right to Buy)	$86.6	07/17/2025		D(1)(2)			6,500	(6)	(6)	Common Stock	6,500	(6)	0	D
Stock Option (Right to Buy)	$54.13	07/17/2025		D(1)(2)			28,500	(6)	(6)	Common Stock	28,500	(6)	0	D
Stock Option (Right to Buy)	$100.13	07/17/2025		D(1)(2)			26,125	(6)	(6)	Common Stock	26,125	(6)	0	D
Stock Option (Right to Buy)	$61.31	07/17/2025		D(1)(2)			30,000	(6)	(6)	Common Stock	30,000	(6)	0	D
Stock Option (Right to Buy)	$43.15	07/17/2025		D(1)(2)			30,000	(6)	(6)	Common Stock	30,000	(6)	0	D
Stock Option (Right to Buy)	$95.12	07/17/2025		D(1)(2)			30,000	(6)	(6)	Common Stock	30,000	(6)	0	D
Stock Option (Right to Buy)	$96.57	07/17/2025		D(1)(2)			26,400	(6)	(6)	Common Stock	26,400	(6)	0	D

Explanation of Responses:

1. This Form 4 reports securities transacted pursuant to the Agreement and Plan of Merger (the "Merger Agreement") by and among the Issuer, SANOFI, a French societe anonyme ("Parent"), Aventis Inc., a Pennsylvania corporation and wholly owned subsidiary of Parent ("Aventis"), and Rothko Merger Sub, Inc., a Delaware corporation and wholly owned subsidiary of Aventis ("Purchaser").

2. Pursuant to the Merger Agreement, Purchaser completed a tender offer to acquire all of the issued and outstanding shares of common stock of the Issuer, par value $0.001 per share (the "Common Stock"), for (i) $129.00 per share, without interest (the "Cash Offer Price"), plus (ii) one (1) contractual contingent value right per share, representing the right to receive contingent payments in cash, without interest, upon the achievement of certain milestones (each a "CVR" and together with the Cash Offer Price, the "Offer Consideration"). On July 17, 2025 (the "Effective Time"), Purchaser merged with and into the Issuer, with the Issuer surviving as an indirect wholly owned subsidiary of Parent.

3. Represents shares previously granted to the Reporting Person subject to performance-based vesting conditions ("PSUs"), for which the performance conditions associated with such PSUs had not yet occurred. As of the Effective Time, each PSU was deemed earned based on the greater of target and actual performance as of the Effective Time. Pursuant to the terms of the Merger Agreement, at the Effective Time, each PSU was cancelled and automatically converted into the right to receive the Offer Consideration, except that fifty percent of such PSUs that were issued in calendar year 2025 were converted into cash-based awards subject to continued vesting as described in the Merger Agreement based on the Cash Offer Price, plus one CVR for each share underlying such portion of the award.

4. Pursuant to the terms of the Merger Agreement, at the Effective Time, each outstanding restricted stock unit ("RSU"), whether vested or unvested, was cancelled and automatically converted into the right to receive the Offer Consideration, except that fifty percent of such RSUs that were issued in calendar year 2025 were converted into cash-based awards subject to continued vesting as described in the Merger Agreement based on the Cash Offer Price, plus one CVR for each share underlying such portion of the award.

5. Pursuant to the terms of the Merger Agreement, at the Effective Time, each share of Common Stock held by the Reporting Person was tendered in exchange for the Offer Consideration.

6. Pursuant to the terms of the Merger Agreement, at the Effective Time, each stock option that was outstanding, whether vested or unvested, immediately prior to the Effective Time became fully vested and was cancelled and converted into the right to receive for each share subject to such stock option (i) the Cash Offer Price (less the applicable exercise price per share subject to such option) and (ii) one (1) CVR (in each case, without interest and less applicable tax withholdings), except that fifty percent of such options that were issued in calendar year 2025 were converted into cash-based awards subject to continued vesting as described in the Merger Agreement based on the Cash Offer Price (less the applicable exercise price per share subject to such option), plus one CVR for each share underlying such portion of the option.

	/s/ Melissa Masse, Attorney-in-Fact	07/21/2025
	** Signature of Reporting Person	Date
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