Biotherapeutics company PureTech Health plc (LSE: PRTC) announced on Monday that it has completed a successful End-of-Phase 1 meeting with the U.S. Food and Drug Administration and received Fast Track designation for LYT-200 in combination with a hypomethylating agent for relapsed/refractory high-risk myelodysplastic syndromes (HR-MDS) FDA feedback supports progression to the Phase 2 STRIDE-MDS trial, which PureTech plans to advance through its Founded Entity, Gallop Oncology.

The randomised, double-blind Phase 2 trial is expected to enroll about 125 patients, comparing LYT-200 at 12mg/kg or 7.5mg/kg with a hypomethylating agent against placebo plus a hypomethylating agent. The study will assess complete and partial response rates to support dose selection.

In the completed Phase 1b trial, efficacy-evaluable patients receiving 12mg/kg LYT-200 plus a hypomethylating agent achieved a 27.3% complete response rate and 45.5% overall response rate, with an 18% conversion-to-transplant rate. No dose-limiting toxicities or myeloid suppression were reported.

PureTech intends to secure external capital in the first half of 2027 to fund LYT-200's continued development through completion of the Phase 2 trial.