MaaT Pharma partners with Clinigen to launch Europe’s first microbiome therapy for aGvHD

MaaT Pharma signed an exclusive commercialization and supply deal with Clinigen to distribute its microbiome therapy, Xervyteg (MaaT013), for acute Graft-versus-Host Disease (aGvHD) across Europe.

Why it matters: If approved, Xervyteg could become the first microbiota-based treatment for aGvHD in Europe and the first in hemato-oncology worldwide, offering a critical solution for patients resistant to standard steroid treatments.

Backstory: Xervyteg is a first-in-class, off-the-shelf microbiome therapy targeting steroid-resistant aGvHD, a life-threatening complication of stem cell or bone marrow transplants. The treatment includes ButycoreTM, a group of bacterial species known to produce anti-inflammatory metabolites.

Big picture: This deal not only advances treatment options for aGvHD but also signals growing momentum for microbiome-based therapies in oncology, potentially transforming how immune-mediated diseases are treated.

The deal: Clinigen, a leader in rare disease drug access, will handle hospital distribution and MaaT’s Early Access Program, for which the demand grew 75% between 2023 and 2024. MaaT Pharma will receive €10.5M upfront, with up to €18M in milestone payments and mid-thirties royalty on net sales.

What’s next: The European Medicines Agency began reviewing Xervyteg in June 2025, and the marketing authorization is expected by mid-2026.