MaaT-013

IMMUNOLIFE, a Phase 2 randomized exploratory study, will evaluate the potential of MaaT033 in combination with Cemiplimab versus Best Investigator Choice (i.e.: second line) in enhancing disease control rate in patients with Non-Small Cell Lung Cancer (NSCLC) who have received antibiotics The IMMUNOLIFE trial is sponsored by Gustave Roussy, a world-renowned center in cancer treatment and conducted within the IMMUNOLIFE consortium, which brings together leading experts in immuno-oncology including Lisa Derosa, MD, PhD This exploratory trial assesses the rationale for combining a full-ecosystem microbiotherapy with immune checkpoint inhibitors (ICIs) in patients presenting antibiotic-induced dysbiosis and improve clinical outcomes This collaboration will generate additional data to advance MaaT034 program in immuno-oncology and the Company’s microbiome-informed AI platform Lyon, France, January 20, 2026 – 6:30pm 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, announced that the first patient has been randomized in the IMMUNOLIFE Phase 2 clinical trial, a randomized multicenter study evaluating the potential of an oral pooled fecal microbiotherapy (MaaT033) in combination with Regeneron’s Cemiplimab (CB) in enhancing disease control rate versus best investigator’s choice (BIC) in patients with advanced non-small cell lung cancer (NSCLC) who have developed resistance to PD-1/PD-L1 blockade following antibiotic (ATB) exposure and who present ATB-induced gut dysbiosis. The IMMUNOLIFE trial is evaluating MaaT033 in combination with CB vs BIC in 162 patients with advanced NSCLC who are refractory to immune checkpoint inhibitors (ICIs) and have received antibiotics. Patients are randomized (1:1) to receive either MaaT033 orally for one week prior to each cycle of CB (administered every 3 weeks for 6 months), followed by CB alone, or BIC. The primary objective is to assess whether the combination is associated with an improved disease control rate at 12 weeks compared to BIC. The study includes 14 centres in France, with patient enrolment of approximately 2 years and total CB treatment duration of 2 years. Primary results after 1-year follow-up post-treatment could be expected in late 2030. An interim futility analysis around H1 2027, after the 81st randomized patient. “Gut dysbiosis is increasingly recognized as a risk factor for immunoresistance to immunotherapy. MaaT033 is designed to restore microbiome balance and may help improve patients’ response to treatment,” said Lisa Derosa, MD, PhD at Gustave Roussy and coordinating investigator of the IMMUNOLIFE trial. “We have built substantial evidence in our hemato-oncology programs that complex donor-derived products restore immune homeostasis in the context of pre-existing dysbiosis. This study represents an opportunity to further explore these findings in immuno-oncology in a well-defined patient population expected to show antibiotic-mediated dysbiosis,” said Hervé Affagard, CEO and co-founder of MaaT Pharma. This trial, sponsored by Gustave Roussy, is part of MaaT Pharma’s exploratory strategy launched in 2022, which also includes the PICASSO trial, a Phase 2a randomized controlled trial sponsored by AP-HP in Paris evaluating Xervyteg® (MaaT013) in combination with ICIs, ipilimumab (Yervoy®) and nivolumab (Opdivo®) for patients with metastatic melanoma. The Company has been informed by PICASSO’s academic sponsor that topline results could not be available in Q4 2025 (as previously announced) and could now be expected in H1 2026. Overall, IMMUNOLIFE and PICASSO studies aim to contribute to the ongoing assessment of the Company’s research strategy, including indication, treatment line, and patient population. This will also inform on the clinical development of MaaT034, a co-cultured microbiome-based therapy and the Company’s next-generation drug candidate, designed to target large indications in solid tumors. In parallel, data already generated and to be generated during the IMMUNOLIFE consortium will also fuel the Company’s AI platform and support the development of all the Company’s microbiome-based drug candidates. The IMMUNOLIFE consortium includes leading academic institutions such as Gustave Roussy, INSERM, Paris Saclay University, INRAe, Hospital-University Institute (IHU) Méditerranée Infection and biotech companies. The consortium aims to address the challenge of primary resistance to ICI observed in advanced NSCLC patients following antibiotic exposure. The IMMUNOLIFE consortium receives funding from the French National Research Agency (“ANR-21-5 RHUS-0017 IMMUNOLIFE”). For more information on the IMMUNOLIFE (IMMUNOLIFE2) study: NCT07001618 About MaaT033 MaaT033, a standardized, donor-derived, high-richness, high-diversity oral Microbiome Ecosystem TherapyTM containing anti-inflammatory ButycoreTM species, is currently being developed as an adjunctive therapy to improve overall survival in patients receiving HSCT and other cellular therapies. It aims to ensure optimal microbiota function and to address a larger patient population in a chronic setting. MaaT033 has been granted Orphan Drug Designation by the European Medicines Agency (EMA). About MaaT034 MaaT034, currently in preclinical development, is a next-generation donor-independent full ecosystem synthetic microbiome therapy, dedicated to improving patient responses to immunotherapy in combination with Immune Checkpoint Inhibitors. Developed using the Company’s co-culturing proprietary MET-C platform, MaaT034 is optimized for large-scale production in oncology. Previous presented preclinical data showed that MaaT034 produced key metabolites, recognized as promoting gut barrier restoration and modulating immune responses, such as Short-Chain Fatty Acids (SCFA), secondary bile acids, and tryptophan derivatives. These data support the role of MaaT034 in gut barrier repair and in T cell reactivation either in combination with anti-PD1 or with anti-PD-L1. By enhancing gut barrier repair and modulating immune responses, MaaT034 is expected to complement the action of these immunotherapeutic agents, potentially improving their efficacy in treating solid tumors cancer. 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. 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.

Presentation included previously disclosed primary results from the pivotal ARES Phase 3 single-arm trial evaluating MaaT013 (Xervyteg ® ) in treating refractory severe acute Graft-versus-Host Disease (aGvHD) patients with gastrointestinal involvement following corticosteroid and ruxolitinib failure. MaaT Pharma announces final pivotal ARES results including a confirmed 1-year overall survival of 54%. Oral presentation and results confirm durable survival benefit in this high-risk patient population known for extremely poor prognosis. MaaT013 (Xervyteg ® ) is currently under regulatory review by the European Medicines Agency (EMA) for Market Approval, with a decision expected mid-2026. LYON, France--(BUSINESS WIRE)--Regulatory News: 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 Prof. Malard, MD, PhD, hematology professor at Saint-Antoine Hospital and Sorbonne University and ARES Trial lead investigator, presented the results for the pivotal ARES, single arm, open label trial evaluating MaaT013 (Xervyteg®) in aGvHD during an oral session at the 67th American Society of Hematology (ASH) Annual Meeting and Exposition currently taking place in Orlando, Florida, USA. In addition, the Company announced new data from the pivotal ARES trial including a 1-year overall survival rate of 54%, confirming the global clinical benefit of MaaT013 (Xervyteg®). “These results confirm that MaaT013 (Xervyteg®) offers a durable clinical benefit for patients with GI-aGvHD who have exhausted all currently approved treatment options. Achieving a 62% gastrointestinal response at Day 28, maintaining responses over time, and reaching a 54% one-year overall survival represent a meaningful step forward in addressing this critical unmet need,” said Prof. Florent Malard, MD, PhD, Professor of Hematology at Saint-Antoine Hospital and Sorbonne University, and lead investigator of the ARES trial who presented the findings. Prof. Malard detailed primary and secondary endpoints, noting that GI-Overall Response Rate (GI-ORR) at Day 28 (62% including 38% of complete response) remains high over time, indicating a durable response with a GI-ORR of 47% and all-organ ORR of 45% at Day 56. At three months, GI-ORR and all-organ ORR were both still high at 44%. These results indicate that responses to MaaT013 (Xervyteg®) are durable and result in improved survival outcomes, which translates into a 54% 1-year overall survival rate in the study population. Final efficacy data of MaaT013 (Xervyteg®) in the ARES study are summarized below. The ARES trial is a single-arm, open label trial evaluating MaaT013 (Xervyteg®) as third-line treatment in 66 adult patients with severe GI-aGvHD refractory to corticosteroids and ruxolitinib across 50 sites in six European countries: Patient profile: 91% (n=60) presented with Grade III–IV aGvHD with GI involvement 86% (n=57) were steroid-resistant and 14% (n=9) steroid-dependent; all were refractory to ruxolitinib Male: 53%, Female: 47% Final results: GI-ORR at Day 28 occurred in 41/66 patients (62%) and prevalently consisted of complete response (CR) (38%, 25/66 patients), and very good partial response (VGPR) (20%, 13/66 patients). All-organ ORR at Day 28 occurred in 42/66 patients (64%) patients and was similarly driven by high rates of CR (36%, 24/66 patients) and VGPR (18%, 12/66 patients). GI-ORR at Day 56 was maintained at 47% (31/ 66 patients) and prevalently consisted of CR (35%, 23/66 patients). All-organ ORR at Day 56 was 45% (30/66 patients) and prevalently consisted of CR (35%, 23/66 patients). GI-ORR and all-organ ORR at 3 months were both 44% (29/ 66 patients), with a prevalence of CR (36%, 24/66 patients). Overall survival (OS) at 12 months was 54% (median survival not reached), this confirms the 12-month probability of survival of 54% announced in January 2025 for the topline results. Median overall survival was not reached, indicating that more than half of the patients were still alive at the end of the study. This suggests a durable survival benefit and reinforces the strong efficacy signal observed in the pivotal ARES study. The median OS of responders was not reached, while it was only 54 days for non-responders. The OS was significantly higher in patients who had a GI response at Day 28 than those who did not respond: 68% vs 28% respectively (p <0.0001), indicating a strong association between early GI response and improved survival in refractory GI-aGvHD. Safety data showed that MaaT013 (Xervyteg ® ) was associated with an acceptable tolerability profile in severe aGvHD patient population (as reviewed continuously by a Data and Safety Monitoring Board). The pivotal ARES trial results will soon be submitted for publication in a leading peer-reviewed medical journal. MaaT013 (Xervyteg®) is currently under review by the European Medicines Agency (EMA) following the submission of a marketing authorization application in June 2025, with a decision expected in mid- 2026, as previously announced. If approved, MaaT013 (Xervyteg®) would become the first microbiotherapy in oncology in the world and the first 3rd-line therapy in aGvHD addressing a critical unmet need. --- 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 gastro-intestinal 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 second-line treatment for steroid-refractory acute graft-versus-host disease (SR aGvHD) is ruxolitinib and remestemcel—L-rknd was approved in December 2024 in the US specifically for use in the paediatric population as a second-line treatment. About Xervyteg® (MaaT013) 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. Xervyteg® (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). 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 steroid-resistant, gastrointestinal (GI)-aGvHD. Xervyteg® (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.