Biogen's Dapirolizumab Pegol Shows Promise in Lupus Treatment, Poised to Compete with Industry Giants

Biogen and UCB's collaborative effort in developing dapirolizumab pegol, a CD40L inhibitor, has yielded impressive results in the treatment of systemic lupus erythematosus (SLE), potentially positioning the drug as a formidable competitor in a market currently dominated by AstraZeneca and GSK.

Phase III PHOENYCS GO Trial Demonstrates Significant Quality of Life Improvements

The latest data from the Phase III PHOENYCS GO trial, presented at the 2025 American College of Rheumatology conference, revealed that dapirolizumab pegol significantly enhanced the quality of life for patients with moderate to severe active SLE. The study, which included over 300 participants, showed that patients receiving dapirolizumab pegol every four weeks, in addition to standard care, experienced greater improvements in fatigue, pain, and body image compared to those on placebo.

Moreover, the trial demonstrated superior outcomes in physical and emotional health, as well as notable enhancements in intimate relationships, planning, and reduced burden on others. These findings build upon previously reported clinical outcomes from November 2024, where dapirolizumab pegol achieved a response rate of 49.5% versus 34.6% for placebo, along with a 1.8-fold greater improvement in disease activity measures.

Market Implications and Competitive Landscape

Jefferies analysts project that dapirolizumab pegol has the potential to achieve peak sales exceeding $1 billion, positioning it as a significant player in the lupus treatment market. The drug is set to compete directly with established therapies such as AstraZeneca's Saphnelo and GSK's Benlysta, which currently boast a combined annual revenue of approximately $3 billion.

In 2024, Saphnelo experienced a remarkable 70% growth, reaching $474 million in global sales, while Benlysta generated nearly $2 billion, marking a 14% annual increase. The robust performance of these competitors underscores the lucrative nature of the lupus treatment market and the opportunity that lies ahead for Biogen and UCB.

Future Outlook and Ongoing Research

To further solidify dapirolizumab pegol's position in the market, Biogen is currently conducting the Phase III PHOENYCS FLY study, also focusing on patients with moderate to severe SLE. This trial is actively recruiting participants and is scheduled for primary completion in May 2028.

Jefferies analysts view dapirolizumab pegol as one of several late-stage, potential blockbuster pipeline programs for Biogen that could gain increased attention in 2026, ahead of the anticipated second Phase III readout in 2027-28. The accumulating data and ongoing research suggest that Biogen is poised to make a significant impact in the lupus treatment landscape, potentially reshaping the competitive dynamics of this important therapeutic area.