Sec Form 4 Filing - SQUINTO STEPHEN P @ SpringWorks Therapeutics, Inc. - 2019-03-29

FORM 4 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 Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person SQUINTO STEPHEN P 2. Issuer Name and Ticker or Trading Symbol SpringWorks Therapeutics, Inc. [ SWTX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O SPRINGWORKS THERAPEUTICS, INC., 100 WASHINGTON BLVD. 3. Date of Earliest Transaction (MM/DD/YY) 03/29/2019 (Street) STAMFORD, CT06902 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 Option (Right to Buy) $ 18 09/12/2019 A 29,983 ( 1 ) 09/12/2029 Common Stock 29,983 $ 0 29,983 D Series A Convertible Preferred Stock ( 2 ) 03/29/2019 A 40,000,000 ( 2 ) ( 2 ) Common Stock 6,078,103 ( 2 ) 6,078,103 I See footnote ( 3 ) Series B Convertible Preferred Stock ( 4 ) 03/29/2019 A 6,931,142 ( 4 ) ( 4 ) Common Stock 1,053,204 ( 4 ) 1,053,204 I See footnote ( 3 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other SQUINTO STEPHEN P C/O SPRINGWORKS THERAPEUTICS, INC. 100 WASHINGTON BLVD. STAMFORD, CT06902 X X Signatures /s/ Michael V. Greco as Attorney-in-Fact 09/16/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )This option shall vest in equal monthly installments over the period of thirty six (36) months following September 12, 2019, subject to continued service to the Issuer on each vesting date. ( 2 )On March 29, 2019, pursuant to a corporate reorganization, all of the equity interests in SpringWorks Therapeutics, LLC were exchanged for the same number and class of newly issued securities of SpringWorks Therapeutics, Inc. Pursuant to the reorganization, OrbiMed Capital GP VI LLC ("GP VI") received 40,000,000 shares of Series A Convertible Preferred Stock of the Issuer. Each share of Series A Convertible Preferred Stock is convertible into shares of the Issuer's Common Stock on a 6.5810:1 basis. Immediately prior to the closing of the Issuer's initial public offering, all shares of Series A Convertible Preferred Stock will convert into shares of Common Stock of the Issuer. The Series A Convertible Preferred Stock has no expiration date. ( 3 )Shares held by GP VI. GP VI is the general partner of OrbiMed Private Investments VI, LP ("OrbiMed VI"). OrbiMed Advisors LLC ("Advisors") is the managing member of GP VI. By virtue of such relationship, GP VI and Advisors may be deemed to have voting and investment power with respect to the shares held by OrbiMed VI and as a result may be deemed to have beneficial ownership of such shares. The reporting person is an Executive Partner at Advisors. This report shall not be deemed an admission that the reporting person is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose. ( 4 )On March 29, 2019, GP VI acquired 6,931,142 shares of Series B Convertible Preferred Stock of the Issuer. Each share of Series B Convertible Preferred Stock is convertible into shares of the Issuer's Common Stock on a 6.5810:1 basis. Immediately prior to the closing of the Issuer's initial public offering, all shares of Series B Convertible Preferred Stock will convert into shares of Common Stock of the Issuer. The Series B Convertible Preferred Stock has no expiration date.

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* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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