MaaT Pharma's Microbiome Therapy Shows 62% Response Rate in Severe Graft-versus-Host Disease
核心洞察
MaaT Pharma (搜索)'s MaaT013 demonstrated a 62% gastrointestinal overall response rate at Day 28 in the Phase 3 ARES trial for severe acute graft-versus-host disease (搜索) refractory to standard treatments.
The microbiome therapy achieved 54% overall survival at 12 months, with patients showing early response having significantly better outcomes (68% vs 28% survival at one year).
MaaT013 is currently under review by the European Medicines Agency (搜索) following a Marketing Authorization Application submission in June 2025, with a decision expected mid-2026.
MaaT Pharma (搜索) announced final results from its Phase 3 ARES pivotal trial showing that MaaT013, a microbiome ecosystem therapy, achieved a 62% gastrointestinal overall response rate (GI-ORR) at Day 28 in patients with severe acute graft-versus-host disease (搜索) (aGvHD) refractory to standard treatments. The data was presented during the Presidential Plenary Session at the 2026 Annual Meeting of the European Society for Blood and Marrow Transplantation (EBMT) in Madrid, Spain.
Trial Design and Patient Population
The ARES trial was a single-arm, open-label study evaluating MaaT013 as third-line treatment in 66 adult patients with severe GI-aGvHD across 50 sites in six European countries. The patient population represented a challenging cohort, with 91% (n=60) presenting with Grade III-IV aGvHD with gastrointestinal involvement. Additionally, 86% (n=57) were steroid-resistant and 14% (n=9) steroid-dependent, with all patients being refractory to ruxolitinib.
Efficacy Outcomes
The trial demonstrated sustained response rates across multiple time points. GI-ORR at Day 28 occurred in 41 of 66 patients (62%), predominantly consisting of complete response (38%, 25/66 patients) and very good partial response (20%, 13/66 patients). All-organ ORR at Day 28 was similarly robust at 64% (42/66 patients).
Response durability was maintained over time, with GI-ORR at Day 56 sustained at 47% (31/66 patients) and at 3 months at 44% (29/66 patients). The therapy showed durable response characteristics, with an estimated cumulative incidence of loss of response at 12 months of 20% (95% CI: 9 to 33) for gastrointestinal response.
Survival Benefits
Overall survival at 12 months reached 54%, with median overall survival not reached, indicating that more than half of the patients remained alive at study completion. Notably, patients who achieved a gastrointestinal response at Day 28 demonstrated significantly superior survival outcomes compared to non-responders: 68% versus 28% respectively (p <0.0001) at one year. The median overall survival for Day 28 responders was not reached, while it was only 54 days for non-responders.
Professor Florent Malard, MD, PhD, hematology professor at Saint-Antoine Hospital and Sorbonne University, emphasized the clinical significance of these findings: "Gastrointestinal acute GvHD (搜索) remains a profoundly devastating condition, associated with dismal outcomes. The response rates observed in the ARES trial—62% GI-ORR at Day 28, sustained at 47% at Day 56 and 44% at Month 3—together with a 54% one-year overall survival, strongly suggest that this therapeutic approach may provide a clinically meaningful benefit for these patients."
Safety Profile
A Data and Safety Monitoring Board (DSMB) provided ongoing safety oversight throughout the study. The final DSMB review conducted in March 2025 reported that "the study results show an acceptable safety profile and a favorable benefit/risk ratio."
Regulatory Status and Next Steps
MaaT013 is currently under review by the European Medicines Agency (搜索) (EMA) following the submission of a Marketing Authorization Application in June 2025, with a regulatory decision expected mid-2026. The therapy has been granted Orphan Drug Designation by both the US Food and Drug Administration (搜索) (FDA) and the European Medicines Agency (EMA).
About MaaT013
MaaT013 (brand name Xervyteg (搜索)®) is a full-ecosystem, off-the-shelf, standardized, pooled-donors, enema Microbiome Ecosystem Therapy for acute hospital use. The therapy is characterized by consistently high diversity and richness of microbial species and the presence of ButyCore™, a group of bacterial species known to produce anti-inflammatory metabolites. MaaT013 aims to restore the symbiotic relationship between the patient's functional gut microbiome (搜索) and their immune system (搜索) to correct immune function responsiveness and tolerance, thereby reducing steroid-resistant gastrointestinal aGvHD.
The ARES trial results have been submitted to a peer-reviewed medical journal for potential publication and will be presented during an oral presentation by Professor Malard on March 27, 2026, during the annual congress of the French Society of Hematology in Paris.