Ownership Submission

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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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(Print or Type Responses)

1. Name and Address of Reporting Person ^*

Merck & Co., Inc.

2. Date of Event Requiring Statement (Month/Day/Year)
01/07/2024

3. Issuer Name and Ticker or Trading Symbol
Harpoon Therapeutics, Inc. [HARP]

(Last)

(First)

(Middle)

126 EAST LINCOLN AVENUE,

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

_____ Director	__X__ 10% Owner
_____ Officer (give title below)	_____ Other (specify below)

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

(Street)

RAHWAY, NJ 07065

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 Beneficially Owned

1.Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock, par value $0.0001	0 ⁽¹⁾ ⁽²⁾ ⁽³⁾ ⁽⁴⁾	I ⁽¹⁾ ⁽²⁾ ⁽³⁾ ⁽⁴⁾	See Footnotes ⁽¹⁾ ⁽²⁾ ⁽³⁾ ⁽⁴⁾

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾	⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾	Common Stock, par value $0.0001	0	$ ⁽¹⁾ ⁽²⁾ ⁽³⁾ ⁽⁴⁾	I	See Footnotes ⁽¹⁾ ⁽²⁾ ⁽³⁾ ⁽⁴⁾

Reporting Owners

Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
Merck & Co., Inc. 126 EAST LINCOLN AVENUE RAHWAY, NJ 07065		X
MERCK SHARP & DOHME LLC 126 EAST LINCOLN AVENUE, P.O. BOX 2000 RAHWAY, NJ 07065		X

Signatures

/s/ Robert M. Davis, Robert M. Davis, Chairman and Chief Executive Officer		01/17/2024
^**Signature of Reporting Person		Date
/s/ Sunil A. Patel, Sunil A. Patel, SVP, Business Development & Licensing		01/17/2024
^**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(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).
(1)	This Form 3 is being filed solely due to the entry by Merck Sharp & Dohme LLC ("Parent") and Hawaii Merger Sub, Inc. ("Purchaser") into Support Agreements (each, a "Support Agreement") with certain stockholders of Harpoon Therapeutics, Inc. (the "Company"). The Support Agreements were entered into in connection with the Agreement and Plan of Merger (the "Merger Agreement"), dated as of January 7, 2024, by and among the Parent, Purchaser and the Company. For additional information regarding the Support Agreements and the Merger Agreement, see the Schedule 13D filed by the Reporting Person with the Securities and Exchange Commission on January 17, 2024 (the "Schedule 13D").
(2)	Purchaser is a direct wholly-owned subsidiary of Parent and Parent is a direct wholly-owned subsidiary of Merck & Co., Inc. ("Merck", and together with Parent, the "Reporting Persons"). As a result of certain provisions contained in the Support Agreements, the Reporting Persons may be deemed to have beneficial ownership of the shares of common stock covered by the Support Agreements and beneficially owned by the stockholders party thereto (an aggregate of 3,080,815 shares, which represent approximately 17.48% of the Company's total outstanding shares as of the close of business on January 7, 2024, based on the representations made by the Company in the Merger Agreement) for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act")).
(3)	Each of the Reporting Persons declare that the filing of this Form 3 shall not be construed as an admission that the Reporting Persons are the beneficial owners of any securities reported in this Form 3.
(4)	Generally, upon the exercise of any security convertible or exchangeable for any common stock of the Company by the stockholders party to the Support Agreements, such shares of common stock acquired upon exercise thereof shall be subject to the Support Agreements and the Reporting Persons may be deemed to have beneficial ownership of such additional shares of common stock, if any. The Reporting Persons expressly disclaim any beneficial ownership of the securities reported herein, and the Reporting Persons do not have any pecuniary interest (as defined in Rule 16a-1(a)(2) of the Exchange Act) in any of the shares subject to the Support Agreements.

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