MaaT Pharma has announced a positive second Data Safety and Monitoring Board (DSMB) review for its ongoing Phase 2b PHOEBUS trial evaluating MaaT033 in patients receiving allogeneic hematopoietic stem cell transplantation (Allo-HSCT). The independent DSMB recommended that the trial proceed without modification, citing a consistent good safety profile and tolerability for MaaT033, a pooled donor-derived drug candidate in oral formulation.
The PHOEBUS trial is the largest randomized controlled trial to date assessing microbiome therapy in oncology. The DSMB, composed of five independent experts, convenes every six months to review safety data. As of the cutoff date of October 31, 2024, the review included data from 59 patients and concluded that MaaT033 is well-tolerated with an acceptable safety profile.
Trial Design and Patient Enrollment
The Phase 2b PHOEBUS trial is an international, multi-center, randomized, double-blinded study testing MaaT033 against placebo as an adjunctive treatment for patients undergoing Allo-HSCT. The trial aims to enroll 387 patients across up to 56 clinical investigation sites in France, Germany, Belgium, Spain, Netherlands, and the United Kingdom. Patient enrollment is progressing steadily, with 80 patients enrolled as of the end of December 2024 and 54 clinical centers currently open.
MaaT033: A Microbiome Ecosystem Therapy
MaaT033 is an oral, freeze-dried, multi-donor formulation designed to improve overall survival in patients receiving HSCT and other cellular therapies. It is a high-richness, high-diversity Microbiome Ecosystem Therapy containing anti-inflammatory Butycore species. MaaT033 has been granted Orphan Drug Designation by the European Medicines Agency (EMA).
Prior Clinical Data
Previous data from a Phase 1b trial in patients with acute myeloid leukemia (AML) or high-risk myelodysplastic syndrome (HR-MDS) who received intensive chemotherapy (reported in January 2022) and from a Phase 1 trial in patients with Amyotrophic Lateral Sclerosis (ALS) (reported in February 2024) also support MaaT033's favorable safety and tolerability profile.
Upcoming Milestones
Upcoming milestones for the PHOEBUS trial include routine DSMB reviews for ongoing safety every six months, as well as DSMB assessments of mortality imbalance between arms at 60 patients (expected in Q1 2025) and at 120 patients (expected in Q3 2025), after 90 days of follow-up post Allo-HSCT.
"We are pleased to see that the safety profile of MaaT033 remains positive, and the trial is advancing as planned. Additionally, we are proud to report that recruitment for our Phase 2b trial is progressing well, with 80 patients enrolled as of end of December 2024," said Gianfranco Pittari, MD, PhD, Chief Medical Officer of MaaT Pharma.
