On November 5, 2025 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, reported the presentation of updated preclinical data for MaaT034, its next generation drug candidate to be evaluated to improve patient responses to immunotherapy in combination with Immune Checkpoint Inhibitors at the 40th Society for Immunotherapy Cancer Annual Meeting in National Harbor, MD held from November 5 to 9, 2025. The SITC (Free SITC Whitepaper) Annual Meeting is one of the world’s leading scientific and medical conferences focused on cancer immunotherapy. The dataset demonstrates compelling anti-tumor efficacy results and immune activation in germ-free mouse models. New analyses of multi-omic data from these models amplify the results previously presented at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting in April 2025.
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MaaT034, the first-in-class co-cultured full ecosystem product, is designed to optimize intestinal microbiome functions and improve patient responses to immunotherapy in combination with Immune Checkpoint Inhibitors (ICIs). MaaT034 is part of the Company’s MET-C platform, which leverages AI-driven co-culture technology to create donor-independent synthetic microbiome ecosystems at industrial scale, targeting specific disease indications.
To guide further development of MaaT034 in immuno-oncology, and in addition to its preclinical program, MaaT Pharma is also participating in two exploratory, investigator-sponsored clinical trials evaluating its donor-derived drug candidates (MaaT013 and MaaT033), respectively in metastatic melanoma and in non-small cell lung cancer (NSCLC).
Key findings from the presentation at SITC (Free SITC Whitepaper) include:
Metagenomic analysis shows that MaaT034 successfully engrafts in the gut of germ-free mice and reproduces the microbial functions of native-based microbiome ecosystems.
MaaT034 improves dendritic cell (DC)-mediated T cell activation and potentiates anti-tumor effects mediated by anti-PD-1 checkpoint blockade in vitro.
70% of MaaT034 microbial species engraft in mice, ensuring an enduring presence of beneficial bacteria in the gut environment.In human FMT studies, the level of engraftment is significantly associated with positive clinical outcomes across multiple indications, as shown by a recent comprehensive meta-analysis[1].
MaaT034 increases the production of key microbial-derived metabolites such as short-chain fatty acids, secondary bile acids, and tryptophan metabolites in germ-free mice. This translates into an improved gastrointestinal physiology as evidenced by gut mucosal restoration.
MaaT034 optimizes anti-PD1 mediated activity in tumor-bearing, germ-free mice. While anti-PD1 alone reduced tumor growth by 10%, the combination of anti-PD1 and MaaT034 resulted in a 83.7% tumor growth reduction (compared to a 24.2% reduction when using a single strain of Akkermansia muciniphila[2] bacteria). These results demonstrate that improved tumor control is achieved with anti-PD1 in combination with MaaT034, as compared to PD-1 alone or in combination with a reference single bacterial strain.
"With MaaT034, we are entering a new phase in our drug platform development, one that leverages our deep experience in the development of complex microbiome therapies and cutting-edge computational analysis to build a next-generation drug candidate capable of enhancing patient response to immunotherapy," said Sheri Simmons, PhD, Acting Chief Scientific Officer, MaaT Pharma. "These findings strongly support advancing our donor-independent, synthetic microbiome therapy and we look forward to bringing MaaT034 into clinical development."
Details of poster presentation:
Abstract number: 1150
Title: MaaT034, a new co-cultured microbiome ecosystem therapy candidate, potentiates anti-PD1 mediated antitumoral activity in germ-free mice
Presentation Day: Saturday, Nov. 8, 2025
Primary Category: Microbiome and Other Environmental Factors
Upcoming investor and medical conferences participation
November 19-21, 2025 – Société Francophone de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC) annual meeting in Geneva, Switzerland
November 25, 2025 – Investir Day event in Paris, France
December 6-9, 2025 – 67th American Society of Hematology (ASH) (Free ASH Whitepaper) annual meeting in Orlando, Fl, USA
[1] Ianiro, G., Punčochář, M., Karcher, N. et al. Variability of strain engraftment and predictability of microbiome composition after fecal microbiota transplantation across different diseases. Nat Med 28, 1913–1923 (2022). View Source
[2] Akkermansia muciniphila is a commensal bacterium naturally present in large quantities in the gut microbiota of healthy people.
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.
(Press release, MaaT Pharma, NOV 5, 2025, View Source [SID1234659466])