November 20, 2018

Gerald McMahon
Chief Executive Officer
Harpoon Therapeutics, Inc.
4000 Shoreline Court, Suite 250
South San Francisco, CA 94080

       Re: Harpoon Therapeutics, Inc.
           Draft Registration Statement on Form S-1
           Submitted October 24, 2018
           CIK No. 0001708493

Dear Mr. McMahon:

       We have reviewed your draft registration statement and have the
following comments. In
some of our comments, we may ask you to provide us with information so we may
understand your disclosure.

       Please respond to this letter by providing the requested information and
either submitting
an amended draft registration statement or publicly filing your registration
statement on
EDGAR. If you do not believe our comments apply to your facts and circumstances
or do not
believe an amendment is appropriate, please tell us why in your response.

      After reviewing the information you provide in response to these comments
and your
amended draft registration statement or filed registration statement, we may
have additional

Draft Registration Statement on Form S-1

Prospectus Summary
Overview , page 1

1.     We note the disclosure that you "set out to design a T cell engager that
incorporates the
       strengths of BiTEs and improves upon their critical shortcomings in
order to create and
       develop therapies with greater efficacy potential." As your product
candidates have not
       received FDA approval, it is premature to suggest or imply that they are
safe or effective.
       Please revise your disclosure here and any similar statements throughout
       prospectus accordingly.
 Gerald McMahon
FirstName LastNameGerald McMahon
Harpoon Therapeutics, Inc.
Comapany 20, 2018
November NameHarpoon Therapeutics, Inc.
November 20, 2018 Page 2
Page 2
FirstName LastName
Emerging Growth Company Status, page 7

2.       Please supplementally provide us with copies of all written
communications, as defined in
         Rule 405 under the Securities Act, that you, or anyone authorized to
do so on your behalf,
         present to potential investors in reliance on Section 5(d) of the
Securities Act, whether or
         not they retain copies of the communications.
Use of Proceeds, page 72

3.       We note your disclosure that you intend to use the net proceeds to
fund the clinical
         development of HPN424 and HPN536. Please revise to specify how far in
the clinical
         development of each of these two product candidates you expect to
reach with the net
         proceeds. If a material amount of other funds are necessary to
complete the clinical
         development of these two product candidates, state the amounts and
sources of such other
         funds for each product. Refer to Instruction 3 of Item 504 of
Regulation S-K.
Management's Discussion and Analysis of Financial Condition and Results of
Operations, page

4.       Please revise your disclosure to address management's belief as to the
sufficiency of the
         net proceeds from your initial public offering, together with your
then existing cash and
         cash equivalents, to fund your plan of operations for the 12-month
period commencing on
         the date of the prospectus. In this regard, we note your risk factor
disclosure on page 14.
Critical Accounting Policies and Estimates
Fair Value of Common Stock, page 89

5.       Once you have an estimated offering price or range, please explain to
us how you
         determined the fair value of the common stock underlying your equity
issuances and the
         reasons for any differences between the recent valuations of your
common stock leading
         up to the IPO and the estimated offering price. This information will
help facilitate our
         review of your accounting for equity issuances including stock
compensation and
         beneficial conversion features.
HPN424: PSMA-targeting TriTAC
Clinical Development Plan, page 101

6.       We note that you have initiated a Phase 1 clinical trail for HPN424
and that you expect to
         enroll approximately 40 patients. As of a recent date, please revise
to disclose how many
         patients have been enrolled.
Agreements with ACG Biologics, Inc., page 105

7.       We note your disclosure in the first paragraph that you may owe AGC a
"one-time upfront
         payment" for a commercial license to the extent you exercise the
referenced option. This
         payment appears separate and distinct from the payments discussed in
the third
 Gerald McMahon
Harpoon Therapeutics, Inc.
November 20, 2018
Page 3
         paragraph. Please revise to disclose the general range of the one-time
payment similar to
         how you characterized the payments discussed in the third paragraph.
License Agreement with Werewolf Therapeutics, Inc., page 146

8.       We note your disclosure in the second paragraph that you may be
entitled to a royalty on
         net sales if Werewolf commercializes any products under the license
agreement subject to
         a minimum annual royalty payment. Please revise your description of
the royalty rate to
         provide a range that does not exceed ten percent. Additionally, please
revise your
         description of the minimum annual royalty payment to disclose the
general range of the
Choice of Forum, page 156

9.       We note that your forum selection provision identifies the federal
district courts of the
         United States as the exclusive forum for resolving any complaint
asserting a cause of
         action arising under the Securities Act. Please revise your disclosure
to state that by
         agreeing to the provision, investors will not be deemed to have waived
the company's
         compliance with the federal securities laws and the rules and
regulations thereunder.

10.      Please provide us mockups of any pages that include any additional
pictures or graphics to
         be presented, including any accompanying captions. Please keep in
mind, in scheduling
         your printing and distribution of the preliminary prospectus, that we
may have comments
         after our review of these materials.
11.      We note you have filed certain exhibits pursuant to a request for
confidential treatment.
         We will provide any comments we have on your application for
confidential treatment
         under separate cover.
       You may contact Bonnie Baynes at 202-551-4924 or Angela Connell at
202-551-3426 if
you have questions regarding comments on the financial statements and related
matters. Please
contact Donald Field at 202-551-3680 or Dietrich King at 202-551-8071 with any

FirstName LastNameGerald McMahon                                Sincerely,
Comapany NameHarpoon Therapeutics, Inc.
                                                                Division of
Corporation Finance
November 20, 2018 Page 3                                        Office of
Healthcare & Insurance
FirstName LastName