Biogen, UCB announce Phase 3 lupus success and plan another trial, but details are limited

Biogen and UCB announced early Tuesday that their Phase 3 study data for the lupus treatment dapirolizumab pegol were promising enough to warrant a second pivotal trial. This trial aims to confirm the drug's benefits and eventually seek FDA approval. However, the companies have not disclosed many details about the findings.

The Phase 3 PHOENYCS GO study involved 321 patients with moderate-to-severe systemic lupus erythematosus (SLE). Participants received dapirolizumab pegol in addition to standard care. The primary endpoint of the trial, measured by the BICLA composite assessment after 48 weeks, was met, showing that the drug improved disease activity better than standard care alone.

Additionally, the drug demonstrated "clinical improvements" across several secondary endpoints, such as other disease activity measurements and flares. Despite these positive results, Biogen and UCB have not revealed the extent of the benefits or the differences between the active treatment and placebo groups. They also have not indicated whether these differences were statistically significant. A Biogen representative mentioned that no further information would be shared at this time.

The decision to proceed with another pivotal trial before the end of 2024 reflects the companies' confidence in gaining regulatory approval. Initially, Biogen and UCB did not conduct two pivotal studies simultaneously when moving dapirolizumab pegol into Phase 3. According to Diana Gallagher, Biogen's head of lupus development, this staggered approach was deliberate. Gallagher explained that they had specific success criteria in mind and aimed to align with UCB before initiating the next study.

This announcement comes after a 2018 Phase 2 study, which did not achieve statistical significance for its primary endpoint. Despite this, Biogen decided to move forward, focusing on better selecting patients for the trial. Adam Meyers, Biogen’s immunology chief, explained that they targeted patients with persistent active disease and/or an active flare, a "deliberate" choice aimed at refining the patient population.

Meyers also noted that a p-value of 0.07 in the Phase 2 study, while not statistically significant, could be interpreted differently depending on the context, especially in a smaller study. This led Biogen and UCB to continue developing the drug.

Dapirolizumab pegol is described as an "Fc-free polyethylene glycol (PEG)-conjugated antigen-binding (Fab’) fragment.” It works by inhibiting CD40L signaling, a process believed to help reduce the activity of overactive immune cells that contribute to lupus.

Overall, the positive Phase 3 results have encouraged Biogen and UCB to proceed with further trials, with hopes of ultimately bringing dapirolizumab pegol to the market as a new treatment option for lupus patients.