Biogen, UCB Achieve Phase III Lupus Success After Mid-Stage Setback

Biogen and UCB recently announced a major milestone for their potential treatment for systemic lupus erythematosus (SLE), dapirolizumab pegol. According to a topline readout released on Tuesday, the drug candidate successfully met the primary efficacy endpoint in the Phase III PHOENYCS GO study. When combined with standard care, dapirolizumab pegol demonstrated a significant improvement in moderate-to-severe disease activity at the 48-week mark compared to a placebo. Additionally, the investigational drug showed clinical improvements in key secondary endpoints, including disease activity and flare-ups.

From a safety perspective, the side effects of dapirolizumab pegol were consistent with those observed in previous studies and typical for SLE patients treated with an immunomodulator. Diana Gallagher, head of the Alzheimer's disease, multiple sclerosis, and immunology disease units at Biogen, expressed optimism about the results. She stated that the findings suggest dapirolizumab pegol could offer significant benefits for patients suffering from this serious and chronic condition. Encouraged by the positive results, Biogen and UCB plan to initiate another Phase III study of the drug, named PHOENYCS FLY, later this year. Patients from the initial PHOENYCS GO study will continue to be monitored in a long-term open-label study, with full results expected to be presented at an upcoming medical conference.

This Phase III success is particularly noteworthy given the drug's earlier challenges. Dapirolizumab pegol had previously failed its mid-stage Phase IIb study in 2018, where it did not show a dose response at 24 weeks as measured by the British Isles Lupus Assessment Group-based Composite Lupus Assessment. Despite this setback, Biogen and UCB decided to continue their efforts, citing "consistent and potentially meaningful improvements" across most clinical endpoints. The gamble seems to have paid off with the recent positive readout from PHOENYCS GO, although the full extent of the drug's effectiveness remains to be seen.

Analyst reactions to the news have been cautiously optimistic. Stifel analyst Paul Matteis described the readout as a "positive surprise" that could rekindle investor interest in Biogen, which has struggled with the slow launch of its Alzheimer's disease therapy, Leqembi. However, Matteis also warned that the mixed results from the earlier Phase IIb study still cast some doubt, emphasizing the importance of the full data set to fully understand the implications.

Jefferies analyst Michael Yee echoed this sentiment, noting that the press release lacked specific data and highlighting the necessity of a second Phase III study to confirm the drug's benefits. Yee predicted that if dapirolizumab pegol is approved, it could enter the market between 2027 and 2028, potentially generating $1 billion to $2 billion in annual sales. In such a scenario, Biogen and UCB would co-promote the drug and share the revenues evenly.

Overall, the recent success in the PHOENYCS GO study marks a significant step forward for Biogen and UCB's dapirolizumab pegol, offering renewed hope for a promising treatment option for systemic lupus erythematosus. However, further studies and data will be crucial to fully validate the drug's efficacy and safety profile.