Pheast Raises $76M in Series A Funding to Train the Immune System to Feast on Cancer

April 26, 2022

Company Is Developing Groundbreaking Novel Checkpoint Therapies to Harness the Innate Immune System to Fight Cancer Cells

PALO ALTO, Calif., April 26, 2022 — Pheast Therapeutics, a company developing novel checkpoint therapies to fight cancer, today announced it has raised $76 million in Series A funding round led by Catalio Capital Management and ARCH Venture Partners. Alexandria Venture Investments and Risk and Reward (R2) also participated. Pheast plans to use the funds to expand its management, scientific, and administrative teams, as well as towards R&D to advance its pipeline of innate immune checkpoint inhibitors towards the clinic.

Pheast is led by scientific experts Dr. Amira Barkal, MD, PhD, Dr. Irving Weissman, MD, Dr. Ravi Majeti, MD, PhD, and Dr. Roy Maute, PhD. Drs. Weissman and Majeti were co-founders of Forty Seven Inc. (acquired by Gilead in 2020) and were instrumental in the discovery of CD47 as a “don’t eat me” signal and critical to the advancement of CD47-targeting clinical programs to treat multiple hematologic malignancies. Drs. Barkal and Weissman uncovered the role of CD24 as a “don’t eat me” signal and promising target for immunotherapy of solid tumors.

“While cancer immunotherapy has revolutionized the treatment of some tumors, many cancers, including ovarian and breast, have seen lackluster responses to existing immunotherapies, and patients are in dire need of new options,” Dr. Amira Barkal, MD, PhD, Principal Founder, Scientific Director, and Interim CEO at Pheast. “With the help of this funding, we will be much better equipped to increase and expand our research efforts, and in doing so, hopefully bring meaningful responses for treatment-resistant cancers closer to reality.”

“Pheast’s exceptional leadership and differentiated approach to leveraging macrophage checkpoints to develop life-changing cancer therapies have quickly positioned the company as a leader in the immunotherapy space,” said George Petrocheilos co-founder and managing partner of Catalio.

“This investment is emblematic of Catalio’s strategy to identify and back breakthrough biomedical technology companies led by world-renowned, serial scientists with proven track records of launching category-defining businesses,” said Dr. Jacob Vogelstein, co-founder and managing partner of Catalio, who will also be joining Pheast’s Board of Directors.

Spun out of Irv Weissman‘s lab at Stanford University, Pheast is a pre-clinical stage immuno-oncology company focused on targeting immune evasion pathways to activate the innate immune system to fight cancer. However, unlike most cancer immunotherapies, which to date have focused on augmenting adaptive immune responses by targeting T-cells, Pheast’s approach is pioneering in the cancer immunotherapy space for three main reasons:

– Pheast is focused on enhancing the innate immune response to cancer by targeting macrophage checkpoints, also called “don’t eat me” signals;

– Pheast is targeting an entirely new signaling axis through their CD24 pipeline which has shown promise in animals for treating ovarian cancer, breast cancer, and other solid tumors;

– Pheast’s team is developing therapeutic strategies to combine macrophage checkpoint inhibitors with existing anti-cancer therapies including existing immunotherapies, tumor-targeting antibodies, and chemotherapies.

The company’s primary program targets the surface protein CD24, a “don’t eat me” signal commandeered by many cancers, including ovarian and breast cancer, in order to avoid detection and clearance by intra-tumoral macrophages. Pheast is also leveraging its proprietary discovery platform to enable the development of additional novel tumor-specific cancer immunotherapies.

“The first macrophage checkpoint inhibitor discovered was CD47, a molecule upregulated by all cancers to block macrophages from eating and killing cancer cells, but later shown to be a general inhibitor of other disease-causing cells. By discovering how CD47 blocks macrophage eating, we developed general principles to discover other ‘don’t eat me’ signals, and we uncovered CD24 as a major ‘don’t eat me’ component of at least most ovarian and breast cancer cells” said Irv Weissman, co-discoverer of both molecules. “I have come to think about macrophages as micro-computing cells, each counting the sum of the ‘don’t eat me’ signals and ‘eat me’ signals coming from attached cancer cells, then acting if the ratio of ‘eat me’ to ‘don’t eat me’ is such that eating dominates. Our goal is to determine, with precision, how to assess the eat me and don’t eat me signals for each cancer, and to tip the balance to remove each human cancer. We are building the team to excel at achieving this goal.”

“Through their research into macrophages and CD24, Pheast has already demonstrated that blockade of CD24 signaling can lead to impressive results in animal models of some of the most difficult-to-treat and aggressive malignancies, including ovarian cancer and breast cancer,” said Dr. Steven Gillis, Managing Director at ARCH Venture Partners. “ARCH is excited to be a part of the Pheast team’s journey and we look forward to future developments at the company.”

About Pheast

Pheast is a pre-clinical stage immuno-oncology company focused on targeting cancer immune evasion pathways to activate the innate immune system in the fight against cancer. Founded in 2020 and led by scientific experts in innate immunity and cancer immunotherapy, Pheast is aiming to develop novel therapies for some of the most difficult-to-treat and aggressive cancers, as well as women’s cancers including ovarian cancer and breast cancer. 

About Catalio Capital Management L.P.
Catalio Capital Management, L.P., is a multi-strategy life sciences investment firm that focuses on breakthrough biomedical technology companies developing the next generation of drugs, devices, diagnostics and data-driven insights. Catalio’s General Partnership includes over 25 world-renowned scientists with extensive academic bona fides who have also started several successful companies based on their research. Catalio has offices in New York, Baltimore, and London. For more information, visit

About ARCH Venture Partners
ARCH Venture Partners invests in advanced technology companies and is one of the world’s leading early-stage technology venture firms. The firm is a recognized leader in commercializing technologies developed at academic institutions, corporate research groups and national laboratories. ARCH invests primarily in companies it co-founds with leading scientists and entrepreneurs, bringing innovations in life sciences and physical sciences to market. For more information, visit


Company: Roy Maute, Ph.D., [email protected]

Media: Jessica Yingling, Ph.D., [email protected]