Company: WHWK
Filing Date: 2025-01-21
Form Type: PREM14A
Source: 0001193125-25-009599
Chunk: 765

Company: Whitehawk Therapeutics, Inc.
Filing Date: 2025-01-21
Form: PREM14A
Chunk 765
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 agreement upon the earliest to occur, if any, of (i) the Company advising the Placement Agent in writing prior to the Private Placement that it has determined not to proceed with the Private Placement or (ii) December 31, 2024, in the event the Private Placement has not been conducted by such date. D-55

The undersigned hereby represents and warrants that the undersigned has full power, capacity and authority
to enter into this letter agreement. This letter agreement is irrevocable and will be binding on the undersigned and the successors, heirs, personal representatives and assigns of the undersigned. This letter agreement may be delivered via
facsimile, electronic mail (including pdf or any electronic signature complying with the U.S. federal ESIGN Act of 2000, e.g., www.docusign.com or www.echosign.com) or other transmission method and any counterpart so delivered shall be deemed to
have been duly and validly delivered and be valid and effective for all purposes.

This letter agreement shall be governed by, and construed in accordance
with, the laws of the State of New York.

[Signature page follows]

D-56

| Very truly yours,                                                                                 |
| Name of Security Holder (Print exact name)                                                        |
| By:                                                                                               |
| Signature                                                                                         |
| If not signing in an individual capacity:                                                         |
| Name of Authorized Signatory                                                                      
 (Print)                                                                                           |
| Title of Authorized Signatory (Print)                                                             |
| (indicate capacity of person signing if signing as custodian, trustee, or on behalf of an entity) |

D-57

Certain Defined Terms Used in Lock-upAgreement For purposes of the letter agreement to which this Annex A is attached and of which it is made a part:

| • |     | “Call Equivalent Position” shall have the meaning set forth in Rule 16a-1(b) under the Exchange Act. |

| • |     | “Change of Control” means the consummation of any bona fide third party tender offer, merger,                                                                                                                                       
 consolidation or other similar transaction following the completion of the Private Placement and approved by the Board of Directors of the Company, the result of which is that any “person” (as defined in Section 13(d)(3) of the 
 Exchange Act), or group of persons, other than the Company or its subsidiaries, becomes the beneficial owner (as defined in Rules 13d-3 and 13d-5 of the Exchange Act