UCB, Biogen present results from PHOENYCS GO study

UCB and Biogen (BIIB) presented detailed results from the Phase 3 PHOENYCS GO study evaluating dapirolizumab pegol, or DZP, a novel Fc-free anti-CD40L drug candidate, demonstrating significant clinical improvement in disease activity in people living with moderate-to-severe systemic lupus erythematosus, or SLE. The results were shared during an oral, late-breaker presentation at ACR Convergence 2024, the American College of Rheumatology’s annual meeting, in Washington, DC. In the PHOENYCS GO study, dapirolizumab pegol was administered intravenously every four weeks. On the primary endpoint measuring improvement of moderate-to-severe disease activity as assessed by achievement of British Isles Lupus Assessment Group, or BILAG-based Composite Lupus Assessment, or BICLA, after 48 weeks, study participants receiving DZP plus SOC had a statistically significant 14.6% higher response rate than those receiving SOC alone. A higher BICLA response rate reflects a treatment response across all affected organs at baseline and is associated with meaningful clinical benefit. On the first secondary endpoint of BICLA response at Week 24, study participants receiving DZP plus SOC had a 7.9% higher response rate than those receiving SOC alone. However, the difference did not reach statistical significance. Given statistical significance was not achieved for the first key secondary endpoint in the hierarchical testing, analyses for all the subsequent secondary endpoints are descriptive and nominal p-values are included. Subsequent analyses of additional secondary endpoints showed clinical improvements in the DZP group, including SLE Responder Index-4 response, corticosteroid tapering, SLE Disease Activity Index-2K, achievement of Lupus Low Disease Activity State and prevention of severe BILAG flares: 17.1% more participants receiving DZP were able to reduce their corticosteroid dose from greater than 7.5 mg/day prednisone equivalent at baseline to 7.5 mg/day at Week 48. 18.8% higher SRI-4 response rate at Week 48 among study participants who received DZP plus SOC versus those who received SOC alone. A 1.8-fold greater decrease from baseline in SLEDAI-2K in study participants receiving DZP plus SOC compared to SOC alone at Week 48. A 20.9% greater proportion of participants in the DZP group achieved LLDAS at Week 48 compared to SOC alone. Participants receiving DZP plus SOC had 50% fewer severe BILAG flares through Week 48 compared to SOC alone. The safety profile of dapirolizumab pegol was generally favorable. The safety results were consistent with previous DZP studies and with that in study participants with SLE receiving an immunomodulator. In the PHOENYCS GO study, a higher proportion of patients receiving DZP plus SOC had treatment-emergent adverse events compared to SOC alone. The proportion of participants with serious TEAEs was 9.9% in those participants receiving DZP plus SOC compared to 14.8% in those receiving SOC alone. Opportunistic infections were reported in 2.8% of participants receiving DZP plus SOC compared to 0.9% of those receiving SOC alone. Discontinuation of treatment or study participation due to TEAEs occurred in 4.7% of participants receiving DZP plus SOC and 3.7% of participants receiving SOC alone.