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Pheast Therapeutics Receives FDA Fast Track Designation for PHST001 for the Treatment of Ovarian Cancer

Redwood City, Calif., June 3, 2025 – Pheast Therapeutics, a clinical-stage biotechnology company developing novel therapies to unleash the power of macrophages on aggressive, difficult-to-treat cancers, today announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track Designation to PHST001 for the treatment of patients with advanced platinum-resistant ovarian cancer or in combination with chemotherapy in platinum-sensitive ovarian cancer. PHST001 is an investigational anti-CD24 monoclonal antibody designed to enhance innate immune recognition and anti-tumor activity in solid tumors.

““Receiving Fast Track designation from the FDA reinforces the promise of CD24 as a next-generation immuno-oncology target and highlights the potential of PHST001 to address a critical unmet need in the treatment of ovarian cancer,” said Raphaël Rousseau, M.D., Ph.D., Chief Medical Officer, Pheast Therapeutics. “We are committed to advancing PHST001 through the clinic and accelerating its development for cancer patients in urgent need of more effective treatments.”

The FDA’s Fast Track program is designed to facilitate the development and expedite the review of novel potential therapies intended to treat serious conditions and address significant unmet medical needs. Companies whose programs are granted Fast Track designation are eligible for more frequent interactions with the FDA during clinical development and potentially accelerated approval and/or priority review, if relevant criteria are met.

The multicenter, open-label Phase 1 clinical study of PHST001 is actively recruiting patients and will enroll up to 80 patients with advanced relapsed and/or refractory solid tumors (ClinicalTrials.gov Identifier: NCT06840886). The study’s primary objectives include evaluating the safety and tolerability of PHST001 and establishing the recommended Phase 2 dose, with secondary endpoints assessing pharmacokinetics and early signs of anti-tumor activity.

About CD24

CD24 is a cell surface protein that plays a key role in tumor immune evasion by engaging Siglec-10, an inhibitory receptor on macrophages. This interaction suppresses macrophage-mediated clearance of cancer cells, allowing tumors to escape destruction by the innate immune system. CD24 was identified in Dr. Irving Weissman’s lab at Stanford as a novel macrophage checkpoint through groundbreaking work by Dr. Amira Barkal, principal founder of Pheast. Along with her other co-founders, Drs. Irving Weissman, Ravi Majeti and Roy Maute, Pheast’s research opened the door to therapeutic strategies targeting CD24 to drive innate immune responses against cancer.

About PHST001

PHST001 is an anti-CD24 macrophage checkpoint inhibitor designed to overcome immune suppression in the tumor microenvironment. CD24 is highly expressed by many human cancers, including ovarian and triple negative breast cancer (TNBC), and high expression of CD24 is a negative prognostic factor in multiple cancer indications. Pheast has engineered PHST001 to be a best-in-class antibody designed to induce macrophages to phagocytose cancer cells and initiate a powerful immune response.

About Pheast Therapeutics

Pheast is a clinical-stage immuno-oncology company focused on activating the innate immune system in the fight against cancer. Founded on breakthrough research from Dr. Irv Weissman’s lab at Stanford University and led by scientific experts in innate immunity and cancer immunotherapy, Pheast is developing novel therapies for some of the most difficult-to-treat and aggressive cancers. Pheast is backed by leading life sciences investors, including Catalio Capital Management and ARCH Venture Partners. For more info, visit Pheast.com and connect on LinkedIn.

Source: Pheast Therapeutics

Posted: June 2025

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