On November 3, 2025 PureTech Health plc (Nasdaq: PRTC, LSE: PRTC) ("PureTech" or the "Company"), a hub-and-spoke biotherapeutics company dedicated to giving life to science and transforming innovation into value, reported that new data from its ongoing Phase 1b clinical trial evaluating LYT-200, a first-in-class anti-galectin-9 monoclonal antibody, in relapsed/refractory acute myeloid leukemia (AML) will be shared on December 6th, 2025, during the 67th Annual American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting in Orlando, Florida, by its Founded Entity Gallop Oncology. The accepted abstract reflects data as of July 8, 2025, and additional analyses based on a later data cut-off are expected to be presented during the ASH (Free ASH Whitepaper) meeting.

Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:

Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing

                  Schedule Your 30 min Free Demo!

The ongoing, open-label, dose-ranging trial is evaluating LYT-200 both as a monotherapy and in combination with the standard-of-care (SOC) regimen of venetoclax (VEN) and hypomethylating agents (HMA) in a very vulnerable population. All participants in the trial have previously been treated with SOC (median prior lines of treatment: 3; range: 1-7), and their disease had either returned or failed to respond.

The data submitted to ASH (Free ASH Whitepaper) reflect efficacy and safety findings for 31 participants in the monotherapy arm and 39 participants in the combination arm who received LYT-200 weekly at doses ≥7.5mg/kg. As a monotherapy, treatment with LYT-200 resulted in 1 marrow complete response (CR) and 3 partial responses (PRs). Notably, one PR in the monotherapy arm was maintained for 24 months as of the data cut off in an individual whose disease previously progressed following five prior rounds of treatment with SOC. When administered in combination with VEN/HMA, LYT-200 treatment resulted in 12 CRs, 1 PR, and 1 morphological leukemia-free state (MLFS). Importantly, CRs were achieved in this cohort across a diverse range of tumor subtypes, including KRAS, NRAS, HRAS, and JAK2 mutations, in patients who were previously fully refractory to SOC.

When evaluating patients with AML, a CR is the primary goal of treatment and means that no leukemia cells are detectable in the blood, fewer than 5% blasts remain in the bone marrow, and blood counts have returned to normal. Achieving a CR is generally associated with improved outcomes, including longer overall survival. A PR reflects a significant reduction in leukemia burden, with at least a 50% decrease in blasts, while an MLFS indicates that there are no leukemia cells visible and fewer than 5% blasts in the marrow, though blood counts have not yet recovered. While SOC in this advanced relapsed/refractory population typically achieves CR rates of 6-12% and median overall survival is less than 2.5 months,[1] LYT-200 has demonstrated a >30% CR rate in the combination cohort as of the data cut off, underscoring its potential to serve as a meaningful new treatment option.

Across all dose levels and treatment arms, LYT-200 was well tolerated. No dose-limiting toxicities were reported, and there were no LYT-200-related serious adverse events, discontinuations, or deaths. The most common adverse events potentially related to LYT-200 were mild and transient.

"The combination of this level of efficacy with a clean safety profile underscores the importance of advancing LYT-200 into its next phase of development, especially given the high relapse rates and poor survival outcomes in AML," said Luba Greenwood, JD, Chief Executive Officer of Gallop Oncology. "As survival data mature, we believe they could add another compelling dimension to LYT-200’s potential clinical profile for patients with relapsed/refractory AML, including those who have failed VEN/HMA or have mutations associated with poorer prognosis, where the need for new therapies remains urgent."

PureTech intends to share further matured data at ASH (Free ASH Whitepaper), including updated efficacy across dose levels, as well as survival and pharmacokinetic/pharmacodynamic data. Topline efficacy data are expected in the fourth quarter of 2025, with topline survival data anticipated in the first half of 2026. PureTech intends to engage with regulatory authorities to advance LYT-200 into a Phase 2 trial.

About AML and MDS

Acute myeloid leukemia (AML) is an aggressive blood cancer characterized by the rapid growth of abnormal myeloid cells in the bone marrow and blood. It is the most common form of acute leukemia in adults, with a five-year survival rate of less than 30%. Despite available therapies, many patients relapse or fail to respond, and outcomes are especially poor in the relapsed/refractory setting.

Myelodysplastic syndromes (MDS) are a group of rare blood cancers in which the bone marrow does not produce enough healthy blood cells. High-risk MDS often progresses to AML and is associated with limited treatment options and poor survival.

Together, AML and high-risk MDS represent areas of urgent unmet medical need where new therapies with improved efficacy and durability are critically needed. Importantly, the incidence of AML is increasing and the market is expected to grow to $6 billion by 2030, underscoring the scale of the opportunity to bring forward more effective therapies.

About LYT-200

LYT-200 is a fully human IgG4 monoclonal antibody targeting galectin-9, a key oncogenic driver and potent immunosuppressor in cancer. It is being developed for the potential treatment of hematological malignancies and solid tumors with otherwise poor survival rates. In an ongoing acute myeloid leukemia (AML) trial, LYT-200 has demonstrated clinical activity and disease stabilization in heavily pretreated patients, both as a monotherapy and in combination with standard-of-care therapy.

LYT-200 has been granted Fast Track and Orphan Drug designations from the U.S. Food and Drug Administration (FDA) for the treatment of acute myeloid leukemia, underscoring the high unmet need in this disease and the potential for LYT-200 to serve as a meaningful therapeutic option.

(Press release, PureTech Health, NOV 3, 2025, View Source [SID1234659276])