A phase 3 trial of Biogen (NASDAQ:BIIB) and UCB's (OTCPK:UCBJF)(OTCPK:UCBJY) dapirolizumab pegol for systemic lupus erythematosus met its primary endpoint, demonstrating significant improvement in disease activity.

In the study, DZP was given intravenously every four weeks for 48 weeks. Results showed that those on DZP plus standard of care had a statistically significant response rate of 49.5% compared to 34.6% for those on standard of care alone based on the British Isles Lupus Assessment Group (BILAG)-based Composite Lupus Assessment (BICLA).

While a key secondary endpoint, BICLA response at week 24, showed that participants on DZP plus SOC had a 7.9% higher response rate than those on SOC alone, the difference was not statistically significant.

Analyses of other secondary endpoints showed better improvement in the DZP group compared to the SOC group in SLE Responder Index (SRI)-4 response, corticosteroid tapering, SLE Disease Activity Index-2K (SLEDAI-2K), achievement of Lupus Low Disease Activity State (LLDAS), and prevention of severe BILAG flares.

Biogen said the safety profile of DZP was generally favorable.

The biotech noted that it and UCB will begin a second phase 3 trial by the end of the year.