A Vote About Evidence, Not Safety
The Committee for Medicinal Products for Human Use, the European Medicines Agency committee that decides whether drugs reach European patients, has given MaaT Pharma a negative trend vote on MaaT013, the company's microbiome therapy for acute graft-versus-host disease, after a re-examination the company requested. A formal opinion is expected September 18.
The reason matters because of what it is not. The committee did not cite a safety signal that alarmed it, and it did not conclude the therapy fails to work. The CHMP's position, as the company reported it, is that the available clinical data package, primarily because it lacks a randomized controlled trial, does not allow sufficient characterization of the benefit-risk profile.
That is a methodological judgment, and it lands in a disease where methodology is the hardest problem. Gastrointestinal acute graft-versus-host disease follows stem cell transplants, is life-threatening, and has almost no approved treatment options in the steroid-refractory setting. Running a placebo-controlled trial in a population that sick, where clinicians understandably resist randomization, is the central tension of the field.
What the Therapy Is
MaaT013, developed under the name Xervyteg, is a full-ecosystem microbiome therapy made from pooled donor material, standardized and administered as an enema, designed to restore the gut microbiome-immune relationship that a transplant and its drugs disrupt. The science rests on a decade of evidence that gut microbial diversity predicts transplant outcomes, and the company holds orphan drug designations on both sides of the Atlantic.
The company's chief executive, Herve Affagard, called the outcome deeply disappointing and pointed to the unmet need: patients facing a life-threatening condition with limited treatment options. MaaT Pharma says it will assess the implications and evaluate its options.
The strategic problem is that the regulator's implied remedy, a randomized controlled trial, is expensive, and the company's runway is short. Analysts following the stock have flagged that cash extends only into November, meaning a fresh financing round is almost certainly required just to stay on the field, with estimates of at least 20 million euros to fund the next year.
What This Means for the Microbiome Field
The vote will be read by every microbiome company in development as a statement about evidence standards, and it is consistent with the direction regulators have been moving for years: real-world data and compassionate-use experience can support early development, but a marketing authorization in a contested indication eventually requires randomization.
The counterpoint is equally real. In the United States, the FDA approved the first microbiome therapies with data that included randomized trials in a different indication, recurrent C. difficile infection, where the endpoint is easier and the population less fragile. Acute graft-versus-host disease is the harder test, and MaaT013 just failed the European version of it, for now.
The formal opinion on September 18 will make the rejection official unless the committee changes course in its final vote, which happens rarely after a negative trend vote. The company's options then are the familiar ones: appeal, redesign the development program, or partner. For patients with steroid-refractory gastrointestinal graft-versus-host disease, the status quo is unchanged, which is exactly the problem the company was trying to solve.
Primary sources
- MaaT Pharma announcement of the CHMP trend vote for the committee's position and the company's response.
- Yahoo Finance coverage of the negative trend vote for the re-examination details and the September 18 opinion date.