MaaT Pharma Presents Preclinical Data at AACR Annual Meeting Demonstrating Immune Activation and Anti-Tumor Activity of MaaT034

Regulatory News:

MaaT Pharma (EURONEXT: MAAT – the “Company”), a clinical-stage biotechnology company and a leader in the development of Microbiome Ecosystem Therapies^TM (MET) dedicated to enhancing survival for patients with cancer through immune modulation, today presented new preclinical data for MaaT034, the Company’s next generation product, showing compelling anti-tumor efficacy results in germ-free mice at the American Association for Cancer Research (AACR) Annual Meeting 2025 in Chicago, Illinois, taking place from April 25 to 30, 2025.

MaaT Pharma has built a versatile platform combining two complementary approaches. The first one leverages a GMP-compliant approach to produce standardized donor-derived therapies (MaaT013, MaaT033) using pooled donations, proven to restore a rich and diverse gut microbiome for patients with severe dysbiosis and currently in late-stage of clinical evaluation (Phases 2 and 3). In parallel, the Company is advancing a next-generation, AI-driven co-culture technology to develop a donor-independent synthetic microbiome ecosystem at large industrial scale targeting indication-specific diseases. MaaT034, the first-in-class co-cultured product, aims to optimize intestinal microbiome functions and to improve patient responses to immunotherapy in combination with Immune Checkpoint Inhibitors.

Below are the key results presented at AACR for MaaT034:

• Metagenomic analysis shows that MaaT034 reproduces the microbial functions of MaaT013 - the Company’s lead asset, currently evaluated in the randomized Phase 2 PICASSO trial in combination with immune checkpoint inhibitors (ICI), ipilimumab (Yervoy) and nivolumab (Opdivo) for unresectable or metastatic melanoma.
• MaaT034 improves 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.
• MaaT034 increases the production of key microbial-derived metabolites such as short-chain fatty acids 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 muciniphila¹ 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.

“These positive data in tumor-bearing mice demonstrate the significant potential of MaaT034 as a microbiome ecosystem therapy candidate and provide a robust basis for the progression of this therapy into clinical development for solid tumors. We look forward to further evaluating the potential benefits of MaaT034 in the next phases of our research,” said Gianfranco Pittari, MD PhD, Chief Medical Officer, MaaT Pharma.