Pheast Therapeutics Advances PHST001 Anti-CD24 Antibody into Phase 1b Combination Trials
核心洞察
Pheast Therapeutics (搜索) has dosed the first patient in the Phase 1b portion of its ongoing Phase 1 study evaluating PHST001, an IgG4 anti-CD24 (搜索) macrophage checkpoint inhibitor, in combination with chemotherapy (搜索).
The Phase 1b study is designed to evaluate safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary anti-tumor activity of PHST001 combined with established chemotherapy (搜索) regimens.
Initial expansion cohorts are actively enrolling patients with advanced ovarian cancer (搜索), endometrial cancer (搜索), and cholangiocarcinoma (搜索), with additional tumor types potentially explored.
Pheast Therapeutics (搜索) announced that the first patient has been dosed in the Phase 1b portion of its ongoing Phase 1 study of PHST001, an IgG4 anti-CD24 (搜索) macrophage checkpoint inhibitor. The clinical-stage biotechnology company is advancing macrophage-directed immunotherapies for cancer (搜索) treatment.
"The initiation of the Phase 1b combination cohorts marks an important step forward for PHST001 and reflects the progress of our Phase 1 program," said Roy Maute, Ph.D., Co-founder and Chief Executive Officer of Pheast Therapeutics (搜索). "The safety and biological signals we have seen to-date support advancing PHST001 into combination cohorts with established therapies."
Study Design and Objectives
The Phase 1b portion of the study is designed to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary anti-tumor activity of PHST001 in combination with established chemotherapy (搜索) regimens using a suitable dose identified by the Phase 1a portion. To date, the observed safety profile supports continued monotherapy escalation and advancement into combination regimens.
Initial expansion cohorts are actively enrolling patients with advanced ovarian cancer (搜索), endometrial cancer (搜索), and cholangiocarcinoma (搜索). Additional tumor types and combination strategies may be explored as the study progresses.
"Advancing into combination therapy allows us to explore how macrophage activation may enhance the activity of existing treatment approaches," said Raphaël Rousseau, M.D., Ph.D., Chief Medical Officer of Pheast Therapeutics (搜索). "With a dose established for combination evaluation, Phase 1b enables us to further define the potential role of PHST001 across multiple tumor settings."
Mechanism of Action
PHST001 is designed to block CD24 (搜索), a macrophage checkpoint that enables tumor cells to evade innate immune clearance through engagement of Siglec-10 (搜索). By targeting this pathway, PHST001 is intended to promote macrophage-mediated phagocytosis of cancer (搜索) cells and support anti-tumor immune responses.
CD24 (搜索) is a cell surface protein that plays a key role in tumor immune evasion by engaging Siglec-10 (搜索), an inhibitory receptor on macrophages. This interaction suppresses macrophage-mediated clearance of cancer (搜索) cells, allowing tumors to escape destruction by the innate immune system. CD24 is highly expressed by many human cancers, and high expression of CD24 is a negative prognostic factor in multiple cancer indications.
Clinical Development Program
PHST001-101 is an open-label, multicenter Phase 1 study in patients with advanced solid tumors (搜索). Primary objectives include safety, tolerability, and dose optimization, with secondary objectives evaluating pharmacokinetics and preliminary anti-tumor activity. PHST001 received FDA Fast Track Designation for the treatment of ovarian cancer (搜索) in June 2025.
Upcoming Data Presentations
The company will present three abstracts at the American Association for Cancer (搜索) Research (AACR) Annual Meeting 2026, taking place April 17-22 in San Diego. The presentations will include preliminary clinical data and translational findings from the Phase 1a portion of the study, along with two preclinical studies evaluating combination strategies and activity in metastatic models of PHST001.
Pheast has engineered PHST001 to be a potential best-in-class antibody designed to induce macrophages to phagocytose cancer (搜索) cells and initiate a powerful immune response. The company was founded as a spinout from Stanford University and is led by scientific experts in innate immunity and cancer immunotherapy, backed by leading life sciences investors Catalio Capital Management (搜索) and ARCH Venture Partners (搜索).