A phase 3 trial evaluating rilzabrutinib for the treatment of pemphigus did not meet its primary or key secondary endpoints.

Rilzabrutinib is an oral Bruton tyrosine kinase inhibitor currently in development for a number of immune-mediated diseases. The placebo-controlled, phase 3 PEGASUS trial (ClinicalTrials.gov Identifier: NCT03762265) enrolled 131 patients with newly diagnosed or relapsing moderate to severe pemphigus.

Participants were randomly assigned 1:1 to receive rilzabrutinib or placebo. The primary endpoint was complete remission from weeks 29 to 37, defined as the absence of new and established skin lesions, with minimal doses of corticosteroids (≤5mg/day). Key secondary endpoints included cumulative duration of complete remission and time to first complete remission.

No significant difference was observed between the treatment and placebo groups based on the proportion of patients meeting the primary endpoint. The Company stated that more detailed data will be shared at a future medical meeting.

Rilzabrutinib will continue to be investigated in a phase 3 trial for the treatment of immune thrombocytopenia and in a phase 2 study for the autoimmune condition lgG4-related disease. Further studies in various immunological diseases are planned to start later in 2021.

Naimish Patel, Head of Sanofi Global Development, Immunology and Inflammation, said, “We are committed to investigating rilzabrutinib further and progressing our clinical programs forward to deliver new treatment options for patients.”


Sanofi provides update on phase 3 study evaluating rilzabrutinib for the treatment of pemphigus. News release. September 9, 2021. https://www.globenewswire.com/news-release/2021/09/09/2293920/0/en/Sanofi-provides-update-on-Phase-3-study-evaluating-rilzabrutinib-for-the-treatment-of-pemphigus.html.