MaaT Pharma Achieves Primary Safety Endpoint in PICASSO Trial

Safety and feasibility data for live biotherapeutic products administered alongside immune checkpoint inhibitors remain scarce, making MaaT Pharma's preliminary PICASSO findings a reference point for quality and regulatory teams tracking LBP development under evolving EMA and FDA frameworks. The Phase 2a investigator-sponsored study, conducted by AP-HP in collaboration with INRAe and Gustave Roussy, evaluated MaaT013 (Xervyteg®) added to ipilimumab and nivolumab in 70 treatment-naïve metastatic melanoma patients across five French centres.

The trial met its primary objective: no statistically significant difference in Grade 3 or higher adverse events was observed between the MaaT013 arm and placebo. The safety profile was broadly consistent with the established profile of ipilimumab-nivolumab combination therapy, providing a controlled dataset on tolerability when a microbiome ecosystem therapy is layered onto dual immune checkpoint inhibitor regimens.

Response rates, a main secondary endpoint, were comparable between arms and aligned with previously reported outcomes for ipilimumab-nivolumab. Notably, MaaT013 administration produced statistically significant increases in microbiome richness and diversity versus placebo, confirming biological activity of the product. Exploratory analyses further indicate that baseline microbiome composition prior to treatment may influence clinical response, a finding with direct implications for patient stratification protocols and, upstream, for lot-release specifications and donor selection criteria in LBP manufacturing.

These results are derived exclusively from the EU Clinical Trials Information System (CTIS) disclosure submitted by the PICASSO investigators and do not constitute a final scientific publication. Full results and analyses are scheduled for presentation at a future scientific congress. For QA and regulatory leads, the CTIS submission pathway itself is worth noting: the data entered the public domain through mandatory registry disclosure rather than a peer-reviewed publication, a pattern likely to become more common as EU Clinical Trials Regulation transparency requirements mature.

MaaT Pharma's CEO Hervé Affagard indicated the findings will inform patient selection and treatment-setting strategy as the company advances MaaT034 in ICI-refractory patients, the next programme in its microbiome pipeline.

The planned longitudinal microbiome and biomarker analyses from PICASSO, once published, will provide a more granular basis for defining critical quality attributes relevant to LBP process validation and batch consistency.

Source: MaaT Pharma via corporate press release and EU Clinical Trials Information System (CTIS), 6 November 2026.