France-based MaaT Pharma (Euronext: MAAT) has announced it plans to seek a re-examination of the European Medicines Agency's negative opinion on Xervyteg (MaaT013) for steroid-refractory acute graft-versus-host disease (aGvHD) after the CHMP concluded the available data did not adequately demonstrate the therapy's clinical benefit.
The CHMP's negative opinion centered on a single key objection: that the data package, primarily derived from the ARES single-arm study, did not permit sufficient attribution of the observed clinical effect and safety profile to MaaT013 alone, given the use of concomitant therapies to manage aGvHD. MaaT Pharma said the CHRONOS study (Clausen et al., 2026) and real-world evidence from its Early Access Program provide supplementary support for the clinical profile of MaaT013. The ARES study enrolled adult patients with steroid-refractory, gastrointestinal aGvHD; the single-arm design, while common in rare disease settings, created the interpretive challenge the CHMP identified.
Xervyteg is a pooled-donor microbiome enema therapy seeking a first approval for aGvHD with gastrointestinal involvement in adult patients refractory to prior lines of therapy. The negative opinion, formally adopted on June 25, 2026, confirmed a negative trend communicated by the CHMP following an Oral Explanation in May 2026. The company said it will request re-examination, including review by new CHMP rapporteurs and a Scientific Advisory Group of hematology experts. A second opinion is expected in September 2026.