Sec Form 4 Filing - New Leaf Biopharma Opportunities II, L.P. @ Harpoon Therapeutics, Inc. - 2023-10-25

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 New Leaf Biopharma Opportunities II, L.P. 2. Issuer Name and Ticker or Trading Symbol Harpoon Therapeutics, Inc. [ HARP] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O NEW LEAF VENTURES, 156 FIFTH AVENUE, SUITE 820 3. Date of Earliest Transaction (MM/DD/YY) 10/25/2023 (Street) NEW YORK, NY10010 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ 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 Common Stock 10/25/2023 P 1,372,000 ( 1 ) A 1,463,386 ( 2 ) D ( 3 ) ( 4 ) Common Stock 10/25/2023 P 171,500 ( 1 ) A 395,783 ( 2 ) I See Footnote ( 5 ) ( 6 ) 8.000% Series A Redeemable Preferred Stock 10,000 ( 7 ) D ( 3 ) ( 4 )

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 (Ins tr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Common Stock Warrant (Right to Buy) $ 5.8345 ( 8 ) 10/25/2023 P 686,000 10/25/2023 10/25/2026 Common Stock 686,000 ( 1 ) 686,000 D ( 3 ) ( 4 ) Common Stock Warrant (Right to Buy) $ 5.8345 ( 8 ) 10/25/2023 P 85,750 10/25/2023 10/25/2026 Common Stock 85,750 ( 1 ) 85,750 I See Footnote ( 5 ) ( 6 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other New Leaf Biopharma Opportunities II, L.P. C/O NEW LEAF VENTURES 156 FIFTH AVENUE, SUITE 820 NEW YORK, NY10010 X New Leaf Ventures III, L.P. C/O NEW LEAF VENTURES 156 FIFTH AVENUE, SUITE 830 NEW YORK, NY10010 X New Leaf Venture Associates III, L.P. C/O NEW LEAF VENTURES 156 FIFTH AVENUE, SUITE 830 NEW YORK, NY10010 X New Leaf Venture Management III, L.L.C. C/O NEW LEAF VENTURES 156 FIFTH AVENUE, SUITE 830 NEW YORK, NY10010 X New Leaf BPO Associates II, L.P. C/O NEW LEAF VENTURES 156 FIFTH AVENUE, SUITE 830 NEW YORK, NY10010 X New Leaf BPO Management II, L.L.C C/O NEW LEAF VENTURES 156 FIFTH AVENUE, SUITE 830 NEW YORK, NY10010 X Lathi Vijay K C/O NEW LEAF VENTURES 156 FIFTH AVENUE, SUITE 830 NEW YORK, NY10010 X Signatures New Leaf Ventures III, L.P., By: New Leaf Venture Associates III, L.P., its general partner, By: New Leaf Venture Management III, L.L.C., its general partner, By: /s/ Craig Slutzkin, Chief Financial Officer 10/27/2023 Signature of Reporting Person Date New Leaf Venture Associates III, L.P., By: New Leaf Venture Management III, L.L.C., its general partner, by /s/ Craig Slutzkin, Chief Financial Officer 10/27/2023 Signature of Reporting Person Date New Leaf Venture Management III, L.L.C., By: /s/ Craig Slutzkin, Chief Financial Officer 10/27/2023 Signature of Reporting Person Date New Leaf Biopharma Opportunities II, L.P., By: New Leaf BPO Associates II, L.P., its general partner, By: New Leaf BPO Management II, L.L.C., its general partner, By: /s/ Craig Slutzkin, Chief Financial Officer 10/27/2023 Signature of Reporting Person Date New Leaf BPO Associates II, L.P., By: New Leaf BPO Management II, L.L.C., its general partner, By: /s/ Craig Slutzkin, Chief Financial Officer 10/27/2023 Signature of Reporting Person Date New Leaf BPO Management II, L.L.C., By: /s/ Craig Slutzkin, Chief Financial Officer 10/27/2023 Signature of Reporting Person Date /s/ Vijay K. Lathi, Vijay K. Lathi 10/27/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Shares of the Issuer's Common Stock and accompanying warrants were purchased in the Issuer's private placement of Common Stock and warrants pursuant to a Securities Purchase Agreement, dated October 22, 2023, by and among the Issuer and the other purchasers named therein. The shares of Common Stock and warrants acquired were purchased at a price representative of $5.8345 per share of Common Stock and accompanying warrant. ( 2 )Shares reflect a 1:10 reverse stock split of the Issuer's Common Stock effective September 1, 2023. ( 3 )These shares are held directly by New Leaf Biopharma Opportunities II, L.P. ("BPO-II"). The sole general partner of BPO-II is New Leaf BPO Associates II, L.P. ("NLBA-II"). The sole general partner of NLBA-II is New Leaf BPO Management II, L.L.C. ("BPO Management-II"). Each of NLBA-II and BPO Management-II disclaim beneficial ownership of these securities and this report shall not be deemed an admission that NLBA-II or BPO Management-II are beneficial owners of such securities for purposes of Section 16 or any other purpose, except to the extent of their respective pecuniary interests therein. ( 4 )Ronald Hunt, a board member of the Issuer, and Vijay K. Lathi (collectively, the "BPO-II Managing Directors") are managing directors of BPO Management-II and may each be deemed to have shared voting and investment power with respect to these securities. Each of the BPO-II Managing Directors disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein. ( 5 )These shares are held directly by New Leaf Ventures III, L.P. ("NLV-III"). The sole general partner of NLV-III is New Leaf Venture Associates III,L.P. ("NLVA-III"). The sole general partner of NLVA-III is New Leaf Venture Management III, L.L.C. ("Management-III"). Each of NLVA-III and Management-III disclaim beneficial ownership of these securities and this report shall not be deemed an admission that NLVA-III or Management-III are beneficial owners of such securities for purposes of Section 16 or any other purpose, except to the extent of their respective pecuniary interests therein. ( 6 )Ronald Hunt, a board member of the Issuer, and Vijay K. Lathi (collectively, the "NLV-III Manager s") are managing directors of Management-III and may each be deemed to have shared voting and investment power with respect to these securities. Each of the NLV-III Managers disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein. ( 7 )The terms of the Series A Preferred Stock are set forth in the Certificate of Designation filed as Exhibit 3.1 to the Issuer's Form 8-K filed with the Securities and Exchange Commission on March 27, 2023. ( 8 )The exercise price is also subject to adjustment pursuant to the Common Stock Warrant issued on October 25, 2023.

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