PureTech Health plc’s founded entity Gallop Oncology reported positive topline data from a completed Phase 1b study of its lead antibody LYT‑200 in heavily pre‑treated patients with relapsed/refractory high‑risk myelodysplastic syndrome (HR‑MDS) and acute myeloid leukemia (AML). The study enrolled 101 patients across nine U.S. sites and evaluated a 12 mg/kg dose, which was selected as the recommended Phase 2 dose. No dose‑limiting toxicities or infusion‑related reactions were observed.
In the HR‑MDS cohort, 11 efficacy‑evaluable patients received LYT‑200 at the recommended dose, yielding a 27.3 % complete‑response rate, a 9.1 % partial‑response rate, and a 45.5 % overall‑response rate. In the AML cohort, 26 efficacy‑evaluable patients achieved a 30.8 % composite complete‑response rate and a 42.3 % overall‑response rate. Six patients experienced Grade 3 or 4 hematology‑related adverse events, a common baseline finding in advanced MDS/AML populations.
LYT‑200 targets galectin‑9, a key oncogenic driver and potent immunosuppressor in cancer. The fully human IgG4 monoclonal antibody employs a dual mechanism that directly kills tumor cells while restoring anti‑tumor immune function. The program has received Fast Track and Orphan Drug designations from the U.S. Food and Drug Administration for AML.
The data support a 12 mg/kg Phase 2 dose and provide a clear path toward a registration‑ready trial in HR‑MDS. PureTech plans to engage the FDA to discuss a subsequent trial design that could support registration of LYT‑200 in the HR‑MDS indication. The results reinforce PureTech’s hub‑and‑spoke model, which de‑risks assets at the hub level while retaining economic interests in the spoke companies. The company currently has three FDA‑approved products and a strong cash position of approximately $319.6 million as of June 30 2025, although it maintains negative free cash flow typical of clinical‑stage biotechs.
Aleksandra Filipovic, M.D., Ph.D., Head of Oncology at PureTech and Chief Medical Officer of Gallop Oncology, said, “The data from the completed Phase 1b trial highlight the potential for LYT‑200 to offer a differentiated treatment approach across a range of myeloid hematological malignancies. Across patients with R/R HR‑MDS and R/R AML, treatment with LYT‑200 resulted in deep responses with an exceptionally favorable safety profile.” Eric Elenko, Ph.D., President and Co‑founder of PureTech and Acting Chief Executive Officer of Gallop Oncology, added, “The results from this Phase 1b trial provide a strong foundation for the next stage of development of LYT‑200. Our decision to prioritize relapsed/refractory high‑risk MDS reflects a focused and disciplined approach, grounded in both the data generated to date and the potential to address a tremendous patient need. We intend to engage with the FDA to discuss a subsequent trial design with the potential to support registration, while continuing to evaluate the broader potential of LYT‑200.” Amir T. Fathi, M.D., Program Director of the Center for Leukemia at the Mass General Brigham Cancer Institute and Professor of Medicine at Harvard Medical School, noted, “The safety profile, combinatorial potential, and level of clinical activity observed with LYT‑200 in this Phase 1b study across both R/R HR‑MDS and R/R AML is very encouraging, particularly given the number of prior lines of treatment and the risk profile in the populations studied. In R/R high‑risk MDS, where treatment options are extremely limited and outcomes are poor, the findings are particularly notable.”
The stock was trading at $18.05 on the New York Stock Exchange, reflecting investor interest in the positive clinical data.
The content on EveryTicker is for informational purposes only and should not be construed as financial or investment advice. We are not financial advisors. Consult with a qualified professional before making any investment decisions. Any actions you take based on information from this site are solely at your own risk.