UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): April 23, 2021

Harpoon Therapeutics, Inc.

(Exact name of Registrant as Specified in Its Charter)

(650) 443-7400

(Registrant’s Telephone Number, Including Area Code)

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instructions A.2. below):

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b–2 of the Securities Exchange Act of 1934 (§ 240.12b–2 of this chapter).

Emerging growth company  ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐

On April 23, 2021, following a damages phase, the Delaware Chancery Court (the “Court”) issued a memorandum opinion awarding Millennium Therapeutics, Inc. (“Millennium”) $38.2 million in damages, plus pre-judgment interest, on its claim against Harpoon Therapeutics, Inc. (“Harpoon”) for fraud in inducing Millennium’s investment in Maverick Therapeutics, Inc. (“Maverick”). The Court’s opinion states that pre-judgment interest will be calculated as set forth in 6 Del. Code Section 2301(a), which generally provides that the legal rate of interest shall be 5% over the Federal Reserve discount rate. As previously reported, on April 3, 2020, the Court found in favor of Millennium on this claim against Harpoon. The Court found that the false representations were made by Harpoon to induce Millennium’s investment in Maverick in January 2017. The litigation between Harpoon, Millennium and Maverick relates only to Harpoon’s ProTriTAC platform, and has no impact on Harpoon’s TriTAC platform, any programs in development coming out of the TriTAC platform, or any other platforms that Harpoon is developing. The Court ruled in favor of Harpoon on Maverick’s claims for breach of contract and misappropriation of trade secrets and dismissed those claims. As part of that ruling, the Court determined that Harpoon’s ProTriTAC technology is not in a field that is subject to a four year non-compete. The Court found that Millennium had not proved its claims for tortious interference with contract and business relations or unfair competition, and those claims were dismissed.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Dated: April 26, 2021