Company: WHWK
Filing Date: 2025-04-25
Form Type: 424B5
Source: 0001193125-25-097064
Chunk: 5

Company: Whitehawk Therapeutics, Inc.
Filing Date: 2025-04-25
Form: 424B5
Chunk 5
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 our common stock. Therefore, you should read the entire prospectus supplement, accompanying prospectus and any free writing prospectus that we have authorized for use in connection with this offering carefully, including the information incorporated by reference herein and therein, before deciding to invest in our common stock. Investors should carefully consider the information set forth under “Risk Factors” beginning on page S-9of this prospectus supplement and in the documents incorporated by reference into this prospectus supplement.

Overview

We are an oncology company applying advanced technologies to established tumor biology that is intended to efficiently deliver improved cancer
treatments. We have deep experience in chemistry, formulation, and drug delivery, as well as research, clinical, and commercial pharmaceutical development, resulting in successfully taking product candidates from the clinic to approval, launch, and
commercialization.

We recently entered into an intellectual property license agreement with WuXi Biologics (Shanghai FX) Co., Ltd. (“WuXi
Biologics”) for the development and global commercialization of a portfolio of three next generation antibody drug conjugates (“ADCs”) targeting clinically validated, broadly overexpressed tumor antigens in high potential cancer
indications with significant unmet need. These ADCs are constructed utilizing an advanced linker-payload platform called CPT113 that has been shown to provide increased stability in blood circulation and deliver targeted release of a Topoisomerase I
(“TOPO1”) inhibitor payload into cancer cells.

These in-licensed assets originated through the
collaborative efforts of WuXi Biologics, a leading global contract research, development and manufacturing organization, and Hangzhou DAC Biotechnology (“Hangzhou DAC”), a global leader in ADC innovation, where Hangzhou DAC’s CPT113
linker-payload has been conjugated to novel antibodies developed by WuXi Biologics against three tumor targets: Protein Tyrosine Kinase 7, Mucin 16 (“MUC16”) and Seizure-related Protein 6
(“SEZ6”). The antibody targeting MUC16 targets the membrane-bound form of MUC16 (mMUC16). The antibody targeting SEZ6 is a biparatopic SEZ6 antibody targeting two different epitopes on SEZ6. We believe the resulting ADCs will be able to
target cancers expressing these respective tumor markers precisely and deliver the potent, cytotoxic TOPO1 inhibitor at the site of cancer. Each of these ADCs have demonstrated tumor cell binding, tumor cell line cytotoxicity, and in