Regeneron and Sanofi report Dupixent trial met primary, key secondary endpoints

Regeneron (REGN) and Sanofi (SNY) announced that a Dupixent confirmatory Phase 3 trial met the primary and key secondary endpoints for the investigational treatment of patients with uncontrolled, biologic-naive chronic spontaneous urticaria, or CSU, receiving background therapy with antihistamines. CSU is a chronic skin condition that causes sudden and debilitating hives and persistent itch, which can impact quality of life. This trial confirms results from Study A, the first Phase 3 trial of Dupixent in this setting. Earlier this year, Japan was the first country in the world to approve and launch Dupixent for adult and adolescent CSU patients based on the results from Study A. Study C enrolled 151 children and adults who were randomized to receive Dupixent or placebo added to standard-of-care histamine-1 antihistamines. At 24 weeks, efficacy among patients receiving Dupixent compared to placebo was as follows: 8.64-point reduction in itch severity from baseline with Dupixent versus a 6.10-point reduction with placebo. A 15.86-point reduction in urticaria activity severity from baseline with Dupixent versus an 11.21-point reduction with placebo. Notably, 30% of Dupixent-treated patients reported no urticaria compared to 18% of those on placebo. The safety results were generally consistent with the known safety profile of Dupixent in its approved dermatological indications. Overall rates of treatment emergent adverse events were 53% for Dupixent and 53% for placebo. AEs more commonly observed with Dupixent compared to placebo included injection site reactions, accidental overdose and COVID-19 infection. Detailed results from this trial will be provided to the FDA by year-end 2024 in response to the additional data requested for inclusion in the supplemental biologics license application for Dupixent in CSU. These data are also planned for presentation at a forthcoming medical meeting. Outside of Japan, the safety and efficacy of Dupixent for CSU has not been fully evaluated by any regulatory authority.