Biogen, UCB reveal Phase III lupus trial results

In a surprising development, Biogen and UCB revealed in September that a Phase III study of dapirolizumab pegol in patients with moderate-to-severe systemic lupus erythematosus (SLE) had achieved its primary endpoint. This week, the companies presented detailed findings at the annual meeting of the American College of Rheumatology. The PHOENYCS GO study enrolled 321 participants suffering from moderate-to-severe SLE. These patients were randomly assigned to receive either dapirolizumab pegol administered intravenously every four weeks or a placebo, both in addition to standard care treatments.

The primary endpoint results were promising. Patients treated with dapirolizumab pegol showed a statistically significant improvement in response rates compared to those given a placebo. Specifically, the response rate in the dapirolizumab pegol group was 49.5%, which was 14.6% higher than the 34.6% response rate observed in the placebo group. This was evaluated by the British Isles Lupus Assessment Group (BILAG)-based Composite Lupus Assessment (BICLA) after a 48-week period.

Despite this positive primary outcome, the study did not meet its first secondary endpoint. The secondary goal was to measure the BICLA response at week 24, where the difference of 7.9% in favor of dapirolizumab pegol did not reach statistical significance. Consequently, all other secondary endpoints were considered descriptive. These included clinical improvements in corticosteroid tapering, SLE Responder Index (SRI)-4 response, SLE Disease Activity Index-2K, achievement of Lupus Low Disease Activity State (LLDAS), and prevention of severe BILAG flares.

Principal investigator Megan Clowse noted the significance of the findings, stating that participants on dapirolizumab pegol experienced reduced lupus activity while also tapering steroids. This is particularly important for patients living with SLE, as controlling disease activity and reducing steroid use are key treatment goals.

Dapirolizumab pegol functions by inhibiting CD40L signaling. Following the success of the Phase III study, a second late-stage study named PHOENYCS FLY is planned to commence within the year. This upcoming study aims to further explore and confirm the benefits of dapirolizumab pegol for treating SLE.