Biogen and UCB's Dapirolizumab Pegol Shows Promise in Phase III Lupus Trial

Key Insights

• Dapirolizumab pegol (DZP) plus standard of care demonstrated a statistically significant 49.5% response rate in SLE patients, compared to 34.6% with standard care alone.
• The Phase III PHOENYCS GO trial met its primary endpoint, with a treatment difference of 14.6% and a p-value of 0.0110, indicating clinical benefit.
• DZP also achieved key secondary endpoints, including a 1.8-fold greater improvement in SLEDAI-2000 scores (p=0.0001) and more patients achieving Lupus Low Disease Activity State.

Biogen and UCB have announced detailed results from their Phase III PHOENYCS GO trial of dapirolizumab pegol (DZP) in systemic lupus erythematosus (SLE), revealing a statistically significant improvement in patient response rates. The trial's success marks a potential advancement in lupus treatment, where unmet needs remain substantial. The companies are now planning a second Phase III trial to support regulatory approval.

PHOENYCS GO Trial Results

The PHOENYCS GO trial demonstrated that patients treated with DZP plus standard of care achieved a 49.5% response rate, compared to 34.6% in the standard of care alone group. This 14.6% treatment difference was statistically significant (p = 0.0110). DZP, a PEG-conjugated antigen-binding fragment, targets CD40L signaling to reduce B cell activation and dampen the overactive immune response characteristic of SLE.

Secondary Endpoints and Clinical Impact

In addition to the primary endpoint, DZP also met several key secondary endpoints. Patients on DZP showed a 1.8-fold greater improvement in Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2000) scores compared to controls (p = 0.0001). Furthermore, a significantly higher proportion of patients in the DZP arm achieved Lupus Low Disease Activity State at 48 weeks. Corticosteroid tapering was also more pronounced in the DZP group, with 72.4% reducing their dose to ≤7.5 mg/day compared to 52.9% in the control arm, although this difference was not statistically significant.

Safety and Tolerability

The safety profile of DZP was consistent with previous studies, with the drug being generally well-tolerated. Interestingly, serious treatment-emergent adverse events were less frequent in the DZP-treated group compared to the control arm. However, a higher number of participants in the DZP arm discontinued the trial due to toxicities.

Future Directions

Biogen and UCB are moving forward with plans to initiate a second Phase III trial by the end of the year, aligning with regulatory requirements for drug approval. The design and timeline for this study are yet to be disclosed. The successful PHOENYCS GO trial and the upcoming confirmatory study represent a significant step forward in addressing the challenges of treating SLE, a complex and heterogeneous autoimmune disease.