Sec Form 3 Filing - New Leaf Biopharma Opportunities II, L.P. @ Harpoon Therapeutics, Inc. - 2023-03-23

FORM 3 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 830 3. Date of Earliest Transaction (MM/DD/YY) 03/23/2023 (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 8.000% Series A Redeemable Preferred Stock 10,000 ( 1 ) D ( 2 ) ( 3 ) Common Stock 913,860 D ( 2 ) ( 3 ) Common Stock 2,242,839 I See footnotes ( 4 ) ( 5 )

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 Common Stock Warrant (Right to Buy) ( 1 ) $ 0.9789 03/23/2023 03/23/2031 Common Stock 2,994,305 D ( 2 ) ( 3 )

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 830 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 03/27/2023 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 03/27/2023 Signature of Reporting Person Date New Leaf Venture Management III, L.L.C., By: /s/ Craig Slutzkin, Chief Financial Officer 03/27/2023 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 03/27/2023 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 03/27/2023 Signature of Reporting Person Date New Leaf BPO Management II, L.L.C., By: /s/ Craig Slutzkin, Chief Financial Officer 03/27/2023 Signature of Reporting Person Date /s/ Vijay K. Lathi Vijay K. Lathi 03/27/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Shares of the Issuer's non-convertible, non-voting 8.000% Series A Redeemable Preferred Stock, par value $0.0001 per share (the "Series A Preferred Stock"), were purchased by New Leaf Biopharma Opportunities II, L.P. ("BPO-II") in the Issuer's private placement of Series A Preferred Stock and warrants and pursuant to a Securities Purchase Agreement, dated March 22, 2023, by and among the Issuer, BPO-II and the other purchasers named therein. 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. The shares of Series A Preferred Stock and Warrants acquired by BPO-II were purchased at a price representative of $1,000 per share for the Series A Preferred Stock. ( 2 )These shares are held directly by 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. ( 3 )Each of Ronald M. Hunt, a Board member of the Issuer, and Vijay K. Lathi, are the managing directors of BPO Management-II (the "BPO-II Managers"), and may each be deemed to have shared voting and investment power with respect to these securities. Each of the BPO-II 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. Mr. Hunt is a director of the Issuer and, accordingly, files separate Section 16 reports. ( 4 )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. ( 5 )Each of Mr. Hunt, a Board member of the Issuer, and Mr. Lathi, are the managing directors of Management-III (the "NLV-III Managers"), and may 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. Mr. Hunt is a director of the Issuer and, accordingly, files separate Section 16 reports.

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