Company: WHWK
Filing Date: 2025-01-31
Form Type: DEFM14A
Source: 0001193125-25-018470
Chunk: 179

Company: Whitehawk Therapeutics, Inc.
Filing Date: 2025-01-31
Form: DEFM14A
Chunk 179
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pressedin primary and metastatic tumor cells and cancer associated fibroblasts (“CAFs”) in the tumor microenvironment. PTK7 is known to promote cancer growth and invasion. Overexpression of PTK7 is associated with poor prognosis, tumor metastasis and reduced overall survival.

| 1. | Aadi analysis based on Human Protein Atlas, Gepia, and literature review. |

PTK7 is a clinically validated tumor target. In a Phase 1 trial in patients with advanced solid tumors, including PROC, NSCLC or triple-negative breast cancer (“TNBC”), Cofe-Pdemonstrated clinical activity with ORR ranging from 16 to 27% in all evaluable patients and 23 to 46% in the subgroup with moderate or high expression of PTK7 (“PTK7 mod-high”),as confirmed by immunohistochemistry (“IHC”) analysis of tumor tissues. In patients treated every three weeks (“Q3W”) cohort, ORR was up to 46% compared to 27% in patients with PROC compared to patients with PTK7 mod-highPROC, 25% compared to 16% in patients with NSCLC compared to patients with PTK7 mod-highNSCLC and 23% compared to 21% in patients with TNBC compared to patients with PTK7 mod-highTNBC. This is an important finding as PTK7 is an ADC target where a high proportion of marker-positive patients express PTK7 at moderate to high levels. Despite these encouraging signals, Cofe-p’scommercial potential was limited by the reduced dose intensity and narrow therapeutic window driven by toxicities consistent with MMAE-associated class effects, including - 122 -

Grade 3 headache and fatigue. Additionally 25% (28/112) of the Q3W cohort experienced Grade 3 neutropenia. Overall, common treatment-related adverse events included nausea, alopecia, fatigue, headache, neutropenia and vomiting.

| * | Mod-high ORR reflects Aadi analysis of the PTK7 protein expression and best overall response data for Q3W                                                                                 
 cohorts in Figure 2 of Maitland et al. Clin Cancer Research, 2021: 27:4511–20. There were 13, 16, and 13 patients with mod-high PTK 7 expressions in PROC, NSCLC, and TNBC, respectively. |

Emerging Therapies and their Limitations Although there are currently no approved ADCs targeting