September 18, 2026: MaaT Pharma Provides Update on MaaT013 (Xervyteg®) Potential Development Plan Following CHMP Negative Opinion After Re-examination

Date : September 18, 2026

MaaT Pharma Provides Update on MaaT013 (Xervyteg®) Potential Development Plan Following CHMP Negative Opinion After Re-examination

  • The Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) issued a negative opinion on the Company’s application for a Conditional Marketing Authorization (CMA) for MaaT013 (Xervyteg®), confirming the trend communicated on September 15, 2026, following the Oral Explanation
  • During the application process, MaaT Pharma proposed conducting a randomized controlled Phase 3 trial versus Best Available Therapy (BAT), named PHOENIX, which would serve the purpose of regulatory submission in the U.S., Europe and other territories
  • Food and Drug Administration (FDA) Type C feedback supports advancement of the pivotal PHOENIX Phase 3 trial which could enable study initiation leading to a potential first patient enrollment in H1 2027, subject to appropriate funding and regulatory clearance

Lyon, France, September 18, 2026 – 7:30am CET – MaaT Pharma (EURONEXT: MAAT – the “Company”), a clinical-stage biotechnology company and a leader in the development of Microbiome Ecosystem TherapiesTM (MET) dedicated to enhancing survival for patients with cancer through immune modulation, today announced that the CHMP of the EMA has maintained its negative opinion on the CMA application for MaaT013, under the brand name Xervyteg®, for the treatment of acute Graft-versus-Host Disease (aGvHD) in adult patients with gastrointestinal involvement refractory to prior lines of therapy following re-examination. The European Commission is expected to issue its final decision following the CHMP opinion in accordance with the applicable regulatory process1. The Company also indicates that future developments of MaaT013 (Xervyteg®) will focus on advancing the PHOENIX randomized clinical trial, subject to appropriate financing and regulatory clearance. The Company is actively exploring options to start U.S. focused development plan for MaaT013 (Xervyteg®) with a view to enabling potential global registration.

The CHMP maintained its view in its formal opinion adopted on September 18, 2026 that the available clinical data package based on single arm trial does not allow sufficient characterization of the benefit-risk profile of MaaT013 (Xervyteg®). As part of the re-examination process, MaaT Pharma presented plans for PHOENIX, a global randomized controlled Phase 3 trial intended to generate the additional evidence requested by regulators to further characterize the benefit-risk profile of MaaT013.

MaaT Pharma is advancing the U.S. clinical readiness for PHOENIX, including completion of a feasibility assessment across major clinical trial sites in US and other planned countries. In addition, feedback received following a Type C interaction with the FDA supports advancement of PHOENIX as a registrational Phase 3 trial and provides a framework for finalizing the study protocol and progressing U.S. development activities, including clinical site activation.

Subject to appropriate funding and regulatory clearance, PHOENIX is planned to be conducted across the U.S., Europe and sites in other regions and could also support potential future registration submissions, subject to successful execution and positive results.

PHOENIX is a randomized, controlled, open-label Phase 3 trial evaluating MaaT013 (Xervyteg®) versus pre-specified BAT in patients with corticosteroid- and ruxolitinib-refractory aGvHD. The study is expected to enroll approximately 138 patients randomized 1:1 and will evaluate Day 28 all-organ Overall Response Rate as its primary endpoint, alongside key secondary efficacy and safety endpoints.

In this context, the Company is conducting a strategic review of its assets while taking additional cash preservation measures, to further extend its cash horizon to December 2026 (vs November 2026), based on current operational assumptions.

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 the only agent approved for treating SR aGvHD after failure of steroid treatment is ruxolitinib, which is currently approved for this indication in USA and has received approval from the European Medicines Agency’s Committee for Human Medicinal Products (CHMP) on March 25, 2022.

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 is currently under regulatory review by the relevant authorities and has not yet received marketing authorization.  MaaT013 is a full-ecosystem, off-the-shelf, standardized, pooled-donors, enema Microbiome Ecosystem TherapyTM for acute, hospital use. It is characterized by a consistently high diversity and richness of microbial species and the presence of ButycoreTM (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 and their immune system to correct the responsiveness and tolerance of immune functions and thus reduce steroid-resistant, gastrointestinal (GI)-aGvHD. MaaT013 has been granted Orphan Drug Designation by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA).

Forward-looking Statements
All statements other than statements of historical fact included in this press release about future events are subject to (i) change without notice and (ii) factors beyond the Company’s control. These statements may include, without limitation, any statements preceded by, followed by, or including words such as “target,” “believe,” “expect,” “aim”, “intend,” “may,” “anticipate,” “estimate,” “plan,” “project,” “will,” “can have,” “likely,” “should,” “would,” “could” and other words and terms of similar meaning or the negative thereof. Forward-looking statements are subject to inherent risks and uncertainties beyond the Company’s control that could cause the Company’s actual results or performance to be materially different from the expected results or performance expressed or implied by such forward-looking statements.

Acting Chief Scientific Officer

Sheri Simmons

Sheri Simmons, Ph.D., is Acting Chief Scientific Officer at MaaT Pharma. Sheri brings extensive experience in biotechnology, particularly in the microbiome field, having held scientific leadership positions at Seres Therapeutics, Johnson & Johnson’s Microbiome Solutions team, and most recently at Seed Health, a leading probiotics company. In her role, she strengthens the Company’s scientific leadership, overseeing preclinical research, AI/data initiatives, and supporting efforts toward the Marketing Authorization Application of Xervyteg® in aGvHD.

Sheri holds a PhD in Biological Oceanography from the Massachusetts Institute of Technology (MIT) and completed an A.B. in Ecology & Evolutionary Biology at Princeton University, graduating summa cum laude and as a Phi Beta Kappa member, receiving one of six awards for the best senior thesis in the sciences. Sheri holds a PhD in Biological Oceanography from the Massachusetts Institute of Technology (MIT) and completed an A.B. in Ecology & Evolutionary Biology at Princeton University, graduating summa cum laude and as a Phi Beta Kappa member, receiving one of six awards for the best senior thesis in the sciences.

CEO and co-founder

Hervé Affagard

Hervé Affagard is the CEO and co-founder of MaaT Pharma. For the past 15 years, Hervé has been an intra/entrepreneur in the healthcare industry, after starting his career in IT in the steel industry. In late 2014, Hervé co-founded the company alongside Dr. Joël Doré, author of nearly 500 publications, and
one of the world’s most cited authors in the microbiome sphere today, after a professional career that spanned multiple industries. Hervé has led MaaT Pharma’s development from its early concept in 2013 and has been at the forefront of the development of the microbiome healthcare ecosystem in France and Europe. In January 2022, Hervé has been elected President of Allliance Promotion Microbiote, an organization founded in 2021 to support the microbiome sector development in France.

Engineer, MBA