Company: WHWK
Filing Date: 2025-01-31
Form Type: DEFM14A
Source: 0001193125-25-018470
Chunk: 181

Company: Whitehawk Therapeutics, Inc.
Filing Date: 2025-01-31
Form: DEFM14A
Chunk 181
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ofe-P.The in vivoantitumor studies were conducted with human tumor xenografts with - 123 -

moderate to high PTK7 expression in nude mice (n=8 per xenograft). As shown in the figure below, in human SCLC xenograft models NCI-H446 (PTK7-mod),both PTK7-CPT113 and Cofe-Pshowed clear dose response in antitumor activity but PTK7-CPT113 demonstrated increased antitumor activity compared to Cofe-Pat each corresponding dose with tumor regression achieved by PTK7-CPT113 at higher doses. Similar results were also observed in xenograft models from other tumor types. Clinical Development Plan We plan to complete IND-enablingstudies, linker-payload process development, and CMC and submit an IND for the treatment of solid tumors, including NSCLC and PROC, in the second half of 2025. Subject to FDA acceptance, we plan to initiate a Phase 1 trial by the end of 2025. mMUC16-CPT113

| Overview                                                                                                                                                                                                                                      
 Our product candidate mMUC16-CPT113 is a next wave ADC targeting the membrane-bound portion of MUC16, a glycoprotein often overexpressed in cancers of female                                                                                 
 origin, such as ovarian cancer, endometrial cancer, cervical cancer, or breast cancer. MUC16 has been previously a challenging target because a large part of its extracellular portion is often cleaved and released or “shed” into the      
 bloodstream, often called cancer antigen 125 (“CA125”). mMUC16-CPT113 is specifically designed to bind to the membrane-bound portion, which we believe can enable greater therapeutic effect at lower doses. We plan to develop mMUC16-CPT113 
 initially for the treatment of PROC, with potential expansion to other ovarian cancers, endometrial cancer, and/or cervical cancer, aiming to deliver a potential                                                                             
 best-in-class treatment for these large patient populations.                                                                                                                                                                                  |

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| Our in vitro and in vivo studies show consistent cytotoxic activity by mMUC16-CPT113, including in the presence of CA125,                                                                                                                                                                                                              
 suggesting that our product candidate does bind to the right epitope. Our product candidate also has an optimized linker and improved TOPO1 payload, which we expect can improve response rate and reduce toxicity. We plan to complete IND-enabling studies and submit an IND for the treatment of ovarian cancer by the end of