EMA’s CHMP maintained its negative opinion on MaaT013 (Xervyteg) for acute graft-versus-host disease as MaaT Pharma advances the PHOENIX Phase 3 trial.
Written By: Kalyani Boharapi,
M.Pharm (Reg. Affairs)
Reviewed By: Pharmacally Editorial Team
The CHMP formally maintained its negative opinion on September 18, 2026, concluding that the available clinical package, based primarily on a single-arm study, does not sufficiently characterize the benefit-risk profile of MaaT013.
The decision follows the company’s re-examination request after the earlier negative opinion. The European Commission is expected to issue the final decision under the applicable regulatory procedure.
The regulatory issue centers on the evidentiary framework rather than a newly reported safety concern. MaaT Pharma presented plans for PHOENIX during the re-examination to generate comparative evidence against Best Available Therapy (BAT).
MaaT013 Is an Off-the-Shelf Microbiome Therapy
MaaT013 is a full-ecosystem, off-the-shelf, standardized, pooled-donor Microbiome Ecosystem Therapy administered by enema for acute hospital use. The therapy has consistently high microbial diversity and richness and contains Butycore™, a group of bacterial species known to produce anti-inflammatory metabolites.
The therapeutic approach is intended to restore the relationship between the gut microbiome and the immune system and address treatment-induced dysbiosis associated with severe gastrointestinal aGvHD. MaaT013 has received Orphan Drug Designation from both the U.S. FDA and EMA.
Acute GvHD occurs when donor immune cells attack tissues following allogeneic stem cell or bone marrow transplantation. Gastrointestinal involvement can cause severe diarrhea, abdominal pain and intestinal bleeding and is associated with substantial morbidity and mortality. Systemic corticosteroids remain the standard first-line treatment, while ruxolitinib is used after steroid failure.
PHOENIX Will Test MaaT013 Against Best Available Therapy
PHOENIX is planned as a randomized, controlled, open-label Phase 3 study in patients with corticosteroid- and ruxolitinib-refractory aGvHD.
The trial is expected to enroll approximately 138 patients, randomized 1:1 to MaaT013 or pre-specified BAT. The primary endpoint is Day 28 all-organ Overall Response Rate, with additional efficacy and safety endpoints planned.
The company intends to conduct PHOENIX across the United States, Europe and other regions. Unlike the single-arm evidence underlying the European application, the randomized design is intended to provide comparative data that can better characterize treatment benefit and risk.
FDA Feedback Supports Registrational Phase 3 Development
MaaT Pharma has been preparing U.S. clinical sites and conducting feasibility assessments across the United States and other planned trial countries.
Following a Type C interaction, FDA feedback supported advancing PHOENIX as a registrational Phase 3 trial and provided a framework for finalizing the protocol and progressing U.S. development activities, including clinical site activation. The company says the study could support future registration submissions in the U.S., Europe and other regions, subject to successful execution and positive results.
Subject to financing and regulatory clearance, first-patient enrollment could begin in the first half of 2027.
Early Access Remains Available
The CHMP outcome does not end MaaT013’s existing European Early Access Program. The program was reported as active in 13 countries, with more than 300 patients treated since 2019, and MaaT Pharma previously confirmed that the re-examination process did not affect ongoing access for eligible patients.
This distinction is important because MaaT013 remains investigational and has not received marketing authorization in Europe. Early Access Program availability therefore operates separately from a commercial authorization.
Funding Will Determine Development Pace
MaaT Pharma is conducting a strategic review of its assets while implementing additional cash-preservation measures. Based on current operating assumptions, these measures are expected to extend the company’s cash horizon to December 2026, compared with November 2026 previously.
The immediate development priority is therefore PHOENIX. Its progression will depend on securing adequate financing, obtaining the necessary regulatory clearances and completing protocol and site preparations. If initiated as planned, the trial would provide the comparative Phase 3 evidence needed to reassess MaaT013’s potential for regulatory registration across multiple territories.
Reference
MaaT Pharma Provides Update on MaaT013 (Xervyteg®) Potential Development Plan Following CHMP Negative Opinion After Re-examination, MaaT Pharma, 18 September 2026
About the Writer
Kalyani Boharapi(LinkedIn) is a pharmacy professional and healthcare writer currently pursuing an M.Pharm in Regulatory Affairs at Dr. D. Y. Patil College of Pharmacy, with interests in pharmaceutical regulations, drug development, and healthcare innovation. She has academic exposure to dossier preparation, scientific writing, and regulatory documentation. Kalyani has also completed certification courses in Generative AI, AI in Pharma, and Bioinformatics, and actively participates in pharmaceutical conferences to stay updated with emerging trends and advancements in the healthcare and pharmaceutical industry.