An Open-label, Phase 1a/1b Dose Escalation and Expansion Study Evaluating Safety, Pharmacokinetics, Pharmacodynamics, and Antitumor Activity of PHST001 in Adults with Advanced Relapsed or Refractory Solid Tumors

What this Trial Is About

Researchers are evaluating PHST001, an anti-CD24 macrophage checkpoint inhibitor, in adults with advanced relapsed or refractory solid tumors. This multi-center, first-in-human Phase 1a/1b study aims to assess the safety, how the drug moves and works in the body, and its antitumor activity. Phase 1a focuses on PHST001 alone, including some central nervous system tumors, while Phase 1b studies PHST001 combined with chemotherapy in ovarian, endometrial, and cholangiocarcinoma cancers. PHST001 is given as intravenous infusions every three weeks. In Phase 1a, nine dose levels of PHST001 monotherapy will be tested to find the recommended dose for Phase 2. In Phase 1b, participants receive PHST001 combined with standard chemotherapy drugs, including paclitaxel, topotecan, doxorubicin, FOLFIRI, FOLFOX, or gemcitabine. After safety is confirmed in initial groups, additional participants will join tumor-specific expansion groups at a fixed dose. Participants will be monitored for side effects, treatment response, and drug levels through regular visits up to two years. Safety assessments include tracking dose-limiting toxicities, serious adverse events, and treatment-related side effects from the first dose through 90 days after the last dose. Antitumor activity will be measured using imaging criteria like RECIST v1.1 or RANO for CNS tumors. Pharmacokinetic studies will characterize how PHST001 behaves in the body during and after treatment.

A Study of PHST001 in Advanced Solid Tumors