MaaT links microbiome drug to GvHD responses, plans phase 3

MaaT Pharma has posted midphase data on its microbiome treatment for acute graft-versus-host disease (aGvHD), positioning the French biotech to step up its preparations for a phase 3 program.

Investigators enrolled 24 patients who had steroid-refractory, gastrointestinal-predominant aGvHD after hematopoietic stem cell transplantation to get up to three transfers of fecal microbiota from healthy donors. At Day 28, one-third of people in the 21-subject per-protocol analysis had a complete or very good partial response. The overall response rate was 38% in the per-protocol analysis. 

MaaT said the treatment, MaaT013, had an acceptable safety profile in the clinical trial. No increase in infectious disorders was seen. The release of more details is scheduled for upcoming medical conferences. For now, there is little to no public information on secondary endpoints such as safety, the number of multidrug resistant bacteria in feces or the frequency of chronic GvHD.

Lyon, France-based MaaT has seen enough to outline plans to move into phase 3, though, setting it up to validate its treatment in a patient population that has a poor prognosis and limited therapeutic options.  

“Acute GvHD is a devastating disease and treatment is often limited to suppressing the patient’s immune system. The therapeutic effect of our lead candidate MaaT013, especially in such a high-risk patient population, is very encouraging. It further validates our approach of restoring the microbial ecosystem to normalize the immune response,” John Weinberg, M.D., chief medical officer at MaaT, said in a statement.

MaaT originally aimed to enroll 32 subjects in the phase 2 trial but downgraded its target to 24 last year and only covered 21 participants in its per-protocol analysis. The change to the recruitment goal happened at a time when MaaT was contending with the impact of COVID-19 on its study.

As the coronavirus spread last year, the French regulator put restrictions on the collection and use of stools, affecting MaaT’s stool collection and production campaign. The regulator lifted some of the restrictions last summer, freeing MaaT to restart the campaign and begin a phase 1 trial of an oral microbiome formulation of MaaT033 in hematological cancer patients undergoing chemotherapy.