SER-155 for the treatment of patients post-HSCT

The first patient has been enrolled in the SER-155 phase Ib study of an investigational oral microbiome therapeutic named SER-155.¹ This product aims to provide commensal bacteria to the gut microbiome following hematopoietic stem cell transplantation (HSCT), which have been shown to disrupt and reduce the diversity of the intestinal flora. By improving the gut microbiome, SER-155 should reduce the occurrences of gastrointestinal (GI) infections, graft-versus host disease, and bacteremia in patients.

The safety, tolerability, pharmacokinetics, and efficacy of SER-155, along with its impact on the microbiome, will be tested in an open-label, randomized, double-blind, placebo-controlled trial (NCT04995653). This trial aims to enroll 70 adult patients ≥18 years who are undergoing HSCT. The primary endpoints for this study are safety and engraftment, which is the measurement of the therapeutic bacterial growth in the GI tract. Measurements will be taken before and after the treatment course up to Day 100.

SER-155, a bacterial consortium, was designed to try to decrease infection and translocation of bacteria across the GI tract and influence the immune response, with the aim of decreasing GvHD. Patients with reduced microbiome diversity post-HSCT have been demonstrated to exhibit significant morbidity and mortality due to infections and GvHD. For more information on this topic, please see our recent article on microbiome dynamics and prediction of acute GvHD post-allo-HSCT.