PureTech Reports Positive Topline Data from Phase 1b Trial of LYT-200 in Relapsed/Refractory (R/R) High-Risk (HR) Myelodysplastic Syndrome (MDS) and R/R Acute Myeloid Leukemia (AML)
April 22, 2026 – Biotechnology, Clinical Trials, Drug Discovery, Other, Pharmaceutical – Gallop Oncology, PureTech Health, R/R acute myeloid leukaemia, biotherapeutics, clinical trials, monoclonal antibodies
- Phase 1b dataset with LYT-200 demonstrates complete responses and favorable tolerability across both R/R HR-MDS and R/R AML
- PureTech’s Founded Entity, Gallop Oncology, to advance LYT-200 first in R/R HR-MDS, with continued development planned in R/R AML
- Company plans to engage with the U.S. Food and Drug Administration to discuss the design of a subsequent trial in R/R HR-MDS that has the potential to support registration.
22 April 2026 — Massachusetts, US — PureTech Health plc, a hub-and-spoke biotherapeutics company dedicated to giving life to science and transforming innovation into value, today announced positive topline data from the completed Phase 1b clinical trial of LYT-200, a first-in-class, fully human anti-galectin-9 monoclonal antibody, in heavily pretreated patients with relapsed/refractory (R/R) high-risk (HR) myelodysplastic syndrome (MDS) and R/R acute myeloid leukemia (AML). Based on the results, PureTech’s Founded Entity, Gallop Oncology, has selected a recommended Phase 2 dose (RP2D) and intends to engage with the U.S. Food and Drug Administration (FDA) to discuss the design of a subsequent trial that could potentially support registration of LYT-200 in R/R HR-MDS.
“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,” said Aleksandra Filipovic, M.D., Ph.D., Head of Oncology at PureTech and Chief Medical Officer of Gallop Oncology. “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. Importantly, the data in R/R HR-MDS were particularly compelling and support prioritizing this indication, especially given the significant unmet need and lack of successful innovation to help these patients. We intend to engage with the FDA to discuss the design of a subsequent trial in R/R HR-MDS, as our goal is to accelerate delivery of this promising first-in-class therapy to patients while also laying the foundation for broader clinical development, including in AML.”
The completed Phase 1b trial (NCT05829226), conducted across nine U.S. sites, evaluated LYT-200 both as a monotherapy and in combination regimens in two heavily pretreated patient populations.
The study included dose escalation of monotherapy LYT-200, followed by dose escalation of LYT-200 in combination with a hypomethylating agent (HMA; azacitidine or decitabine) in patients with R/R HR-MDS and with venetoclax (VEN) and an HMA in R/R AML.
“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,” said 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. “In R/R high-risk MDS, where treatment options are extremely limited and outcomes are poor, the findings are particularly notable. In this context, the potential to achieve clinical responses without added toxicity would represent a meaningful advance in the MDS treatment landscape and warrants continued clinical development.”
“The results from this Phase 1b trial provide a strong foundation for the next stage of development of LYT-200,” said Eric Elenko, Ph.D., President and Co-founder of PureTech and Acting Chief Executive Officer of Gallop Oncology. “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.”
About Gallop Oncology
Gallop Oncology was founded by and is currently wholly-owned by PureTech Health plc. Gallop is a clinical-stage biopharmaceutical company committed to transforming treatment paradigms for hematologic malignancies. Guided by science and driven to deliver meaningful outcomes for patients, Gallop is advancing a novel approach where efficacy, safety, and durability converge. Its lead candidate, LYT-200, is the most advanced candidate targeting galectin-9, an important oncogenic driver and potent immunosuppressor in cancer, offering a differentiated strategy to address some of the most challenging cancers. For more information, please visit www.galloponcology.com.
About PureTech Health
PureTech Health is a hub-and-spoke biotherapeutics company dedicated to giving life to science and transforming innovation into value. We do this through a proven, capital-efficient R&D model focused on opportunities with validated pharmacology and untapped potential to address significant patient needs. This strategy has produced dozens of therapeutic candidates, including three that have received U.S. FDA approval. By identifying, shaping, and de-risking these high-conviction assets, and scaling them through dedicated structures backed by external capital, we accelerate their path to patients while creating sustainable value for shareholders. For more information, visit www.puretechhealth.com
