BRUSSELS, Belgium and CAMBRIDGE, Mass., June 1, 2026
UCB and Biogen announced the publication of full Phase 3 PHOENYCS GO study results in The Lancet, highlighting the potential of dapirolizumab pegol (DZP) as a novel treatment option for patients with moderate-to-severe active systemic lupus erythematosus (SLE). The investigational Fc-free CD40L inhibitor demonstrated statistically significant improvements in disease activity when added to standard of care compared with placebo plus standard therapy, reinforcing its promise as a potential new therapy for lupus patients with significant unmet medical needs.
Phase 3 PHOENYCS GO Trial Meets Primary Endpoint
The PHOENYCS GO study successfully achieved its primary endpoint, with 50% of patients receiving DZP plus standard of care achieving a BILAG-based Composite Lupus Assessment (BICLA) response at Week 48 compared with 35% of patients receiving placebo plus standard of care (p=0.011). BICLA is a widely accepted measure of clinically meaningful improvement across multiple organ systems affected by lupus. The findings demonstrate that targeting the CD40L pathway with dapirolizumab pegol may provide effective disease control for patients living with active SLE.
Treatment Benefits Extend Across Multiple Clinical Outcomes
Beyond the primary endpoint, the trial showed favorable results across numerous secondary and exploratory measures. Patients treated with DZP experienced improvements in severe disease flares, SRI-4 response rates, SLEDAI-2K scores, skin and joint symptoms, and important serological markers including anti-dsDNA antibodies and complement proteins C3 and C4. The therapy also demonstrated clinically meaningful improvements in FACIT-Fatigue scores, addressing one of the most debilitating symptoms reported by lupus patients. In addition, a greater proportion of patients receiving DZP were able to reduce glucocorticoid use to lower recommended doses, suggesting a potential steroid-sparing effect.
Advertisement
Favorable Safety Profile Supports Continued Development
Dapirolizumab pegol maintained a generally favorable safety profile consistent with previous clinical studies. While treatment-emergent adverse events were more frequently reported in the DZP group, serious adverse events occurred less often compared with placebo, and treatment discontinuation rates remained low in both groups. The encouraging efficacy and safety data support the continued advancement of dapirolizumab pegol through the ongoing Phase 3 PHOENYCS FLY trial, which is currently recruiting patients and is expected to support future regulatory submissions. UCB and Biogen believe the latest findings strengthen the potential of DZP to become an important new treatment option for people living with systemic lupus erythematosus.
Source: UCB, Biogen press release
