Pheast Unveils Preclinical Data for Anti-CD24 PHST001 at SITC 2024

Pheast Therapeutics, a biotechnology company based in Palo Alto, California, has unveiled new preclinical data on its anti-CD24 antibody drug candidate, PHST001. This development was presented at the 39th Annual Meeting of the Society for Immunotherapy of Cancer (SITC), held both virtually and at the George R. Brown Convention Center in Houston from November 6-10, 2024.

PHST001 is designed to target a crucial macrophage "don't eat me" signal on cancer cells, facilitating their destruction by the immune system. The data presented highlight how PHST001, by binding strongly to CD24, activates macrophage-induced phagocytosis in various cancer cells, leading to significant tumor reduction in live models. Furthermore, the drug exhibits a favorable pharmacokinetic profile in non-human primates and does not cause immune-mediated toxicity in vitro.

Dr. Roy Maute, the co-founder and CEO of Pheast Therapeutics, emphasized the significance of these findings, noting that PHST001 could potentially enhance the range of clinical options available to patients with high unmet needs in oncology. He pointed out that macrophage checkpoint therapies like PHST001 might succeed where other immunotherapies have not.

CD24, a protein highly expressed in several human cancers such as ovarian and triple negative breast cancer (TNBC), serves as a negative prognostic marker. By interacting with the macrophage receptor Siglec-10, CD24 helps cancer cells evade immune attack. Pheast has engineered PHST001 to bind with high specificity and affinity to CD24, thereby blocking its interaction with Siglec-10 and allowing macrophages to target and destroy the cancer cells.

Dr. Suzana Kahn, Senior Director of Biology at Pheast Therapeutics, underscored the potential of PHST001 in treating various cancer types. She highlighted the drug's unique position as a novel macrophage checkpoint inhibitor capable of robustly inhibiting CD24 without exhibiting a toxic preclinical profile. The promising efficacy demonstrated in preclinical models supports the move towards initiating first-in-human clinical trials.

The preclinical data were also presented by Dr. Kahn in a poster session, detailing how PHST001, a humanized anti-CD24 antibody, induces the phagocytosis of human tumor cells in vitro and promotes tumor clearance in vivo.

Pheast Therapeutics is a preclinical-stage immuno-oncology company committed to targeting immune evasion pathways to activate the innate immune system against cancer. Led by experts in innate immunity and cancer immunotherapy, Pheast is developing new treatments for some of the most challenging and aggressive cancers, including ovarian cancer and TNBC.