Clinical trials

This is a multi-center, first-in-human (FIH), open-label, Phase 1a/1b dose escalation and dose expansion study to assess the safety, PK, pharmacodynamics, and antitumor activity of PHST001 monotherapy (Phase 1a) or in combination with anticancer therapies (Phase 1b) in adult participants with advanced relapsed and/or refractory solid tumors (including but not limited to CNS tumors in Phase 1a only). Phase 1b will include the following cohorts 1) tumor-specific cohorts for participants with advanced relapsed and/or refractory ovarian cancer, endometrial cancer, and cholangiocarcinoma, 2) a randomized cohort for participants with ovarian cancer who will receive PHST001 in combination with mirvetuximab soravtansine, 3) a cohort for participants with advanced/metastatic breast cancer who will receive PHST001 in combination with trastuzumab deruxtecan and 4) a cohort of patients who consent to additional biomarker studies. The study's primary objectives are to evaluate the safety and tolerability of PHST001 and determine the RP2D (Recommended Phase 2 dose) of PHST001 as monotherapy and in combination with anticancer therapies, as well as to assess the anti-tumor activity of PHST001 in combination with anticancer therapies in Phase 1b.