FDA grants orphan drug designation to antibody-mediated rejection treatment
Ella Day | June 26, 2025 | News story | Research and Development | FDA, Immunology, Orphan Drug Designation, Sanofi, antibody-mediated rejection, clinical trials, immunology, inflammation, organ transplantation
Sanofi has announced that the US Food and Drug Administration (FDA) has granted orphan drug designation (ODD) to riliprubart for the treatment of antibody-mediated rejection (AMR) in solid organ transplantation. The designation recognises the significant unmet need for patients facing AMR – an immune response that can lead to organ damage and transplant failure.
Riliprubart (SAR445088) is a humanised IgG4 monoclonal antibody that selectively targets activated C1s in the classical complement pathway, a key mechanism implicated in AMR. The condition affects a subset of transplant recipients, particularly those who are sensitised with pre-existing antibodies. Currently, there are no FDA-approved therapies specifically for AMR, which remains one of the most serious complications following kidney and other solid organ transplants.
“This designation marks an important milestone in our mission to address critical challenges in transplant medicine,” said Alyssa Johnsen, global therapeutic area development head for immunology and inflammation at Sanofi. “Riliprubart’s novel mechanism could significantly improve outcomes for kidney transplant recipients at risk of or experiencing rejection.”
Riliprubart is currently being evaluated in a phase 2 trial in kidney transplant recipients, targeting both prevention and treatment of active AMR. The antibody is also being studied in two phase 3 trials for chronic inflammatory demyelinating polyneuropathy, demonstrating its broader therapeutic potential across immune-mediated diseases.
Ella Day
26/6/25
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