LYON, France, June 26, 2026
MaaT Pharma announced plans to request a re-examination of the European Medicines Agency (EMA) Committee for Medicinal Products for Human Use (CHMP) negative opinion on its conditional Marketing Authorization Application (MAA) for MaaT013 (Xervyteg®) in the treatment of acute Graft-versus-Host Disease (aGvHD). The decision confirms the negative trend previously communicated following the company’s Oral Explanation in May 2026. MaaT Pharma intends to request that a Scientific Advisory Group (SAG) of hematology experts participate in the review process, while a new independent rapporteur and co-rapporteur reassess the application. Based on current EMA timelines, a second CHMP opinion is expected during the September 14–17, 2026 session, offering the company another opportunity to support the therapy’s clinical value for patients with limited treatment options.
CHMP Cites Clinical Data Concerns Despite Positive Patient Outcomes
The CHMP concluded that the available evidence, primarily generated from the ARES single-arm clinical study, did not sufficiently demonstrate that the observed clinical efficacy and safety could be attributed solely to MaaT013, largely because patients received multiple concomitant therapies during treatment. Despite the negative opinion, MaaT Pharma maintains confidence in the therapy’s benefit-risk profile, emphasizing supportive evidence from the ARES study, the published CHRONOS study, and real-world clinical outcomes from its Early Access Program, which has treated more than 300 patients across 13 countries since 2019. Importantly, the company confirmed that the regulatory review will not affect ongoing patient access, and MaaT013 (Xervyteg®) remains available through the Early Access Program for eligible individuals suffering from severe steroid-refractory gastrointestinal aGvHD, an indication with few effective third-line treatment options.
Microbiome Therapy Targets Critical Need in Severe aGvHD
MaaT013 (Xervyteg®) is a Microbiome Ecosystem Therapy (MET) designed to restore gut microbial diversity and improve immune regulation in patients experiencing severe treatment-induced dysbiosis following stem cell transplantation. The off-the-shelf, standardized therapy is administered by enema and contains a highly diverse microbial ecosystem enriched with Butycore™ bacteria, known for producing anti-inflammatory metabolites. The therapy aims to re-establish the functional relationship between the gut microbiome and the immune system, reducing inflammation associated with steroid-resistant gastrointestinal acute Graft-versus-Host Disease. The investigational product has received Orphan Drug Designation from both the EMA and the U.S. Food and Drug Administration (FDA), highlighting its potential importance in addressing a rare condition associated with high mortality and limited therapeutic alternatives.
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Pipeline Expansion Supports Long-Term Microbiome Strategy
Beyond MaaT013, MaaT Pharma continues expanding its oncology-focused microbiome platform with additional clinical programs designed to strengthen its long-term growth strategy. The company’s oral microbiome candidate, MaaT033, is currently being evaluated in a randomized Phase 2 clinical trial for prophylactic use in hemato-oncology patients, while its next-generation immuno-oncology candidate, MaaT034, extends the company’s microbiome ecosystem technology into broader cancer immunotherapy applications. As the regulatory re-examination progresses, MaaT Pharma remains focused on demonstrating the clinical value of microbiome-based immune modulation while advancing multiple pipeline assets aimed at improving survival outcomes for patients with cancer and other life-threatening immune-related diseases. The upcoming September 2026 CHMP review will represent a critical milestone in determining the future regulatory pathway for MaaT013 (Xervyteg®) in Europe.
Source: AIM ImmunoTech press release
