MaaT Pharma Presents Updated Positive Data in Early Access Program for Xervyteg at the EHA Congress Validating High Efficacy Observed in Pivotal ARES Study in Acute Graft-versus-Host Disease

Regulatory News:

MaaT Pharma (EURONEXT: MAAT – the “Company”), a clinical-stage biotechnology company and a leader in the development of Microbiome Ecosystem Therapies^TM (MET) dedicated to enhancing survival for patients with cancer through immune modulation, today announced that Professor Mohamad Mohty, Professor of Hematology and Head of the Hematology and Cellular Therapy Department at Saint-Antoine Hospital and Sorbonne University, will present updated data for Xervyteg (MaaT013) in treating acute Graft-versus-Host Disease (aGvHD) under the Early Access Program (EAP) at the European Hematology Association (EHA) Annual Congress 2025. This independent EAP dataset further supports the efficacy and safety profile of Xervyteg previously shown in the pivotal ARES trial. It also confirms the breakthrough potential of Xervyteg for aGvHD patients with limited treatment options and it also serves as supportive data within the Marketing Authorization Application (MAA) recently submitted to the European Medicines Agency (EMA).

Key highlights:

• aGvHD is a major cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation. The patients (N=173) treated in EAP previously failed 1 to 6 aGvHD systemic treatment lines and most had grade III (49%) or IV (38%) aGvHD. The real-world data presented underscores the favorable safety profile of Xervyteg the strong and durable responses, translating into increased overall survival:

• Gastrointestinal Overall Response Rate (GI-ORR) of 53% at D28, with Complete Response (CR) observed in 30% of patients; all-organ Overall Response Rate (ORR) was 50% with 26% CR.

• Response is maintained at D56 indicating a long-term disease control with a GI-ORR of 47% and an ORR considering all organs of 46%.

• Overall Survival (OS) in all patients was 55% at 6 months, 48% at 12 months, 44% at 24 months.

• Xervyteg displayed a good overall safety profile in the EAP population.

• OS was significantly higher in patients who responded to Xervyteg (MaaT013) compared to non-responders (69% versus 25% at 12 months, and 61% versus 25% at 24 months).

• Median survival in all patients was 312 days. In responder patients, median survival was 834 days vs 69 days in non-responders.

A subset of patients (n=70) failing both steroid resistant (SR) and ruxolitinib resistant (RR) and thus resembling the cohort enrolled in the pivotal Phase 3 ARES trial (NCT04769895), exhibited a significant and consistent efficacy profile: