Company: WHWK
Filing Date: 2025-01-31
Form Type: DEFM14A
Source: 0001193125-25-018470
Chunk: 286

Company: Whitehawk Therapeutics, Inc.
Filing Date: 2025-01-31
Form: DEFM14A
Chunk 286
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 growing, they may result in a variety of severe symptoms, including pain, organ dysfunction, and in the case of functional (hormone secreting) NETs, intractable
diarrhea, refractory gastric ulcers, or uncontrolled glucose levels that may respond poorly to treatment. While everolimus is approved for NETs based on a progression free survival benefit over placebo, we believe, based in part on everolimus’s
preclinical studies results, that there is an opportunity for nab-sirolimus to provide enhanced therapeutic benefit.

FYARRO - Historical Clinical Development

Advanced Malignant PEComa Trial (AMPECT)

PEComa.AMPECT was the first prospective clinical trial in advanced malignant PEComa. Patients with metastatic or inoperable locally advanced disease
were treated with FYARRO at 100 mg/m2 administered as an IV infusion over 30 minutes on Days 1 and 8 of a 21-day cycle. The primary endpoint for the study was ORR evaluated by independent radiology review.
Secondary efficacy endpoints included duration of response (“DOR”), progression free survival (“PFS”) and overall survival (“OS”). The sample size estimation assumed an observed ORR of 30% for a sample size of 30
patients, which would exclude values less than 14.7% for the lower bound of the 95% confidence interval.

This registrational trial met its primary
endpoint demonstrating the efficacy of nab-sirolimus in this rare disease for which there was no FDA approved treatment, with an independently assessed ORR of 39% (95% CI: 22%, 58%). Disease control (defined as complete or partial response
(“CR” or “PR”) + stable disease ≥12 weeks) was achieved in 71% of patients. FYARRO (nab-sirolimus) was subsequently approved by the FDA for the treatment of advanced malignant PEComa on November 22, 2021.

Sixty-seven percent (8 of 12) of responses were seen at the first scan after baseline at week six (median time to response 1.4 months, 95% CI: 1.3 to 2.8
months). At the time of the primary analysis (predefined as when all patients had an opportunity to be treated for 6 months), the median for the key secondary endpoint of DOR was

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not yet reached, with 9 of 12 responders still on treatment