OSE Immunotherapeutics: Veloxis Treats First Patient in Phase 2 of VEL-101
Partner Veloxis Pharmaceuticals is conducting this phase 2 trial on a molecule initially discovered and developed by the Nantes-based biotech, then licensed in 2021. This milestone is part of the development of pegrizeprument (VEL-101) for the prevention of rejection in kidney transplantation.
A Molecule Licensed to Veloxis for Transplantation
OSE Immunotherapeutics announced on September 9, 2026 that its partner Veloxis Pharmaceuticals had treated the first patient enrolled in the RENGEVITY-201 phase 2 clinical study. This trial evaluates pegrizeprument (VEL-101) in the prevention of organ rejection in patients receiving kidney transplantation. Pegrizeprument, also known as VEL-101 and FR104, is a pegylated monovalent monoclonal antibody fragment discovered and initially developed by OSE Immunotherapeutics. It was licensed to Veloxis in April 2021, with the latter obtaining worldwide rights for development, manufacturing and commercialization for all transplantation-related indications.
A Mechanism of Action Targeting CD28 Co-stimulation
The molecule binds to CD28 and blocks CD28-mediated co-stimulation of effector T cells, without blocking CTLA-4, a protein that helps regulate immune responses. According to the company, the product should thus have a dual mechanism of action, directly blocking CD28-mediated T cell activation while indirectly enabling CTLA-4-mediated immunosuppressive functions. Pegrizeprument is in development to prevent rejection following solid organ transplantation. The U.S. FDA granted it orphan drug designation for the prevention of rejection in liver transplantation in December 2025, then in cardiac transplantation in March 2026. Veloxis remains responsible for worldwide development, manufacturing and future commercialization.
