MaaT Pharma Reports CHMP Maintains Negative Opinion on MaaT013 for Acute Graft-versus-Host Disease
MaaT Pharma (Euronext: MAAT), a clinical-stage biotechnology company developing Microbiome Ecosystem Therapies™ (MET) designed to modulate the immune system and improve outcomes for patients with cancer, announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) has maintained its negative opinion on the company’s application for MaaT013, under the proposed brand name Xervyteg®, following a re-examination.
MaaT013 is being developed for the treatment of acute Graft-versus-Host Disease (aGvHD) with gastrointestinal involvement in adult patients whose disease has remained refractory after prior lines of therapy. The CHMP formally adopted its re-examination opinion on September 18, 2026, concluding that the clinical evidence currently available does not provide sufficient characterization of the product’s benefit-risk profile.
The regulatory development represents an important point in MaaT Pharma’s clinical and regulatory strategy for MaaT013. While the European regulatory review remains unfavorable at this stage, the company is planning to continue development of the program through the proposed PHOENIX randomized Phase 3 clinical trial, subject to securing appropriate financing and obtaining the necessary regulatory clearances.
The company is also evaluating a U.S.-focused development strategy for MaaT013, with the longer-term objective of potentially supporting registration in multiple markets if future clinical development produces positive results.
CHMP Requests Additional Evidence
According to MaaT Pharma, the CHMP maintained its position that the existing clinical data package does not sufficiently establish the benefit-risk profile of MaaT013. A key consideration is that the current evidence is primarily based on a single-arm clinical trial, meaning patients receiving MaaT013 were not evaluated against a randomized control group within that study.
Randomized controlled trials can provide comparative evidence that helps regulators determine whether observed clinical outcomes are attributable to an investigational treatment rather than differences in patient characteristics, disease severity, background treatment, or other factors.
During the re-examination process, MaaT Pharma presented its plans for PHOENIX, a proposed global randomized controlled Phase 3 study intended to generate additional evidence addressing the questions raised during the European regulatory assessment.
The company believes the planned trial could provide a more comprehensive evaluation of MaaT013’s efficacy and safety in patients with difficult-to-treat aGvHD. The trial is designed to compare MaaT013 with a pre-specified best available therapy (BAT) and to evaluate clinically relevant response outcomes.
The European Commission is expected to issue its final decision following the CHMP opinion, in accordance with the applicable regulatory process. Until that decision is issued, the CHMP opinion represents the latest stage of the European regulatory review.
MaaT Pharma Plans PHOENIX Phase 3 Trial
MaaT Pharma said its future development activities for MaaT013 will focus on advancing the PHOENIX randomized clinical trial, provided the company secures appropriate funding and obtains the required regulatory approvals.
PHOENIX is planned as a randomized, controlled, open-label Phase 3 trial evaluating MaaT013 against pre-specified BAT in patients with corticosteroid- and ruxolitinib-refractory acute Graft-versus-Host Disease.
The proposed study is expected to enroll approximately 138 patients, with participants randomized in a 1:1 ratio between the treatment and comparator groups.
The primary endpoint will be Day 28 all-organ Overall Response Rate (ORR). The study will also evaluate key secondary efficacy and safety endpoints to provide a broader assessment of the investigational therapy.
The trial design is intended to generate comparative evidence that can help characterize the potential clinical benefit and safety profile of MaaT013 in a patient population with significant unmet medical needs.
MaaT Pharma’s decision to focus on a randomized Phase 3 study follows the CHMP’s conclusion that the available single-arm evidence does not adequately characterize the benefit-risk profile. If successfully executed, PHOENIX could provide the comparative data necessary for future regulatory discussions and potentially support registration applications.
However, the company has emphasized that progression of the program remains dependent on both financing and regulatory clearance.
U.S. Development Strategy Advances
Alongside its European regulatory activities, MaaT Pharma is working to establish clinical readiness for the PHOENIX program in the United States.
The company has completed a feasibility assessment involving major potential clinical trial sites in the U.S. and other countries planned for the study. This work is intended to support preparation for trial initiation and help determine the operational requirements associated with a multinational Phase 3 clinical program.
MaaT Pharma also reported receiving feedback from the U.S. Food and Drug Administration following a Type C interaction. According to the company, the feedback supports advancement of PHOENIX as a potential registrational Phase 3 trial and provides a framework for finalizing the study protocol and advancing U.S. development activities.
These activities include preparations for clinical site activation, an important operational step before patient enrollment can begin.
The company is evaluating a development strategy that could include clinical sites across the United States, Europe, and other regions. A multinational trial could potentially generate data relevant to regulatory submissions in multiple jurisdictions, subject to successful execution, regulatory requirements, and positive clinical results.
MaaT013 Targets Difficult-to-Treat aGvHD
Acute Graft-versus-Host Disease is a serious complication that can occur following allogeneic hematopoietic stem cell transplantation. The condition develops when immune cells from a donor attack the recipient’s tissues.
The gastrointestinal tract can be significantly affected by aGvHD, and patients with disease that remains refractory despite established treatments can face substantial clinical challenges.
MaaT013 is being developed as a Microbiome Ecosystem Therapy, reflecting MaaT Pharma’s focus on therapeutic approaches involving the human microbiome and immune modulation.
The company’s development strategy is based on the premise that modulation of the intestinal microbiome may influence immune responses and potentially contribute to improved outcomes in patients with certain diseases.
For patients with corticosteroid- and ruxolitinib-refractory aGvHD, treatment options remain an important area of clinical investigation. The proposed PHOENIX trial is intended to evaluate whether MaaT013 can provide clinically meaningful benefits when compared with available treatment options.
Regulatory Outcome Shapes Next Development Phase
The CHMP’s maintained negative opinion means MaaT Pharma must generate additional evidence before MaaT013 could potentially progress toward European approval based on the current application.
The company’s response is to prioritize the development of PHOENIX rather than discontinue the program. The proposed randomized trial is intended to directly address the evidence gap identified during the regulatory assessment.
The outcome also illustrates the importance of trial design in the development of novel therapies for complex diseases. While single-arm studies can generate important clinical evidence, regulators may require randomized comparative data to establish the magnitude of treatment benefit and assess the balance between efficacy and safety.
For MaaT Pharma, PHOENIX is consequently expected to become a central component of the company’s future strategy for MaaT013.
If financing is secured and regulatory requirements are satisfied, the company intends to advance the program toward clinical execution. Positive results from a successful Phase 3 trial could potentially support future regulatory submissions, although such outcomes cannot be guaranteed.
Company Conducts Strategic Review and Cash Preservation Measures
The latest regulatory update comes as MaaT Pharma takes additional measures to manage its financial resources.
The company said it is conducting a strategic review of its assets while implementing additional cash-preservation measures. These actions are intended to extend the company’s cash runway to December 2026, compared with its previous expectation of November 2026, based on current operational assumptions.
The additional month of projected cash runway provides the company with more time to evaluate strategic alternatives, advance clinical preparations, and determine the appropriate path for its development programs.
At the same time, the financing requirement remains a significant consideration for the future of PHOENIX. MaaT Pharma has explicitly stated that advancement of the trial is subject to appropriate funding as well as regulatory clearance.
The company will therefore need to balance its clinical ambitions for MaaT013 with its available financial resources and broader strategic priorities.
Potential Next Steps for MaaT013
MaaT Pharma’s immediate regulatory path in Europe will include the European Commission’s final decision following the CHMP opinion. Meanwhile, the company is preparing for potential development of PHOENIX and continuing discussions and activities related to the U.S. clinical strategy.
The planned trial is expected to enroll approximately 138 patients and compare MaaT013 with best available therapy in corticosteroid- and ruxolitinib-refractory aGvHD. Its primary endpoint, Day 28 all-organ Overall Response Rate, is intended to provide a standardized measure for evaluating patient response.
The company is also assessing clinical trial sites in the United States and other planned regions, while using feedback from its interaction with the FDA to refine the protocol and development pathway.
For MaaT Pharma, the next stage of MaaT013 development will therefore depend on several factors, including regulatory decisions, financing, trial execution, patient enrollment, clinical results, and subsequent regulatory assessment.
Despite the maintained negative CHMP opinion, the company continues to pursue MaaT013 as a potential therapy for patients with difficult-to-treat acute Graft-versus-Host Disease. The proposed PHOENIX Phase 3 study represents the company’s planned effort to generate the randomized comparative evidence needed to further define the therapy’s clinical profile and potentially support future registration applications.
About MaaT Pharma
MaaT Pharma is a leading, late-stage clinical company focused on developing innovative gut microbiome-driven therapies to modulate the immune system and enhance cancer patient survival. Supported by a talented team committed to making a difference for patients worldwide, the Company was founded in 2014 and is based in Lyon, France.
As a pioneer, MaaT Pharma is leading the way in bringing the first microbiome-driven immunomodulator in oncology. Using its proprietary pooling and co-cultivation technologies, MaaT Pharma develops high diversity, standardized drug candidates, aiming at extending life of cancer patients. MaaT Pharma has been listed on Euronext Paris (ticker: MAAT) since 2021.
About acute Graft-versus-Host Disease
Acute Graft-versus-Host Disease occurs in patients within 100 days of undergoing a stem cell or bone marrow transplant, where the transplanted cells initiate an immune response and attack the transplant recipient’s organs, causing inflammation of the skin, liver and/or gastrointestinal tract and leading to significant morbidity and mortality.
GI involvement is associated with severe complications such as profound diarrhea, abdominal pain, intestinal bleeding, and death. These complications are often life-threatening, with increased mortality risk, due to the challenges of managing severe GI inflammation and the associated risks of infection, malnutrition, and organ failure. The standard first-line therapy for treating aGvHD is the use of systemic steroids. If patients do not respond to steroids, they are considered steroid resistant (SR) and other agents can be administered.
Currently, ruxolitinib is the standard second-line treatment for steroid-refractory acute graft-versus-host disease. More recently, remestemcel-L (rknd) was approved in December 2024 in the United States, specifically for use in the pediatric population as a second-line treatment.
About MaaT013 (Xervyteg®)
MaaT Pharma’s Microbiome Ecosystem Therapies (MET) are designed to leverage a full microbiome ecosystem to restore balance and maximize clinical benefits for patients with severe, treatment-induced dysbiosis in acute diseases. MaaT013 (Xervyteg®) is a full-ecosystem, off-the-shelf, standardized, pooled-donors, enema Microbiome Ecosystem Therapy™ for acute, hospital use. It is characterized by a consistently high diversity and richness of microbial species and the presence of Butycore™ (a group of bacterial species known to produce anti-inflammatory metabolites).
Xervyteg® (MaaT013) aims to restore the symbiotic relationship between the patient’s functional gut microbiome and their immune system to correct the responsiveness and tolerance of immune functions and thus reduce the symptoms of steroid-resistant, gastrointestinal (GI)-aGvHD. MaaT013 (Xervyteg®) has been granted Orphan Drug Designation by the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA).