Dapirolizumab Pegol Shows Phase 3 Benefit in Active SLE

Key Takeaways

• Dapirolizumab pegol was associated with a higher week 48 BICLA response than placebo in active SLE.
• The phase 3 trial was randomized, double-blind, placebo-controlled, lasted 48 weeks, and was conducted on top of standard care.
• Treatment-emergent adverse events were common in both groups, serious infections were reported in both arms, and the dapirolizumab pegol group included infusion hypersensitivity, one myocardial infarction, and one death.

In the phase 3 PHOENYCS GO trial, week 48 BICLA response was 50% with dapirolizumab pegol and 35% with placebo in patients with active SLE with standard care.

PHOENYCS GO was a 48-week, randomized, double-blind, placebo-controlled phase 3 trial conducted at 177 centers in 25 countries. Participants were aged 16 years or older, had moderate-to-severe active SLE despite standard-of-care medication, and were assigned 2:1 to intravenous dapirolizumab pegol 24 mg/kg or placebo every 4 weeks plus standard care. Among 643 screened patients, 321 were randomly assigned, with 213 allocated to dapirolizumab pegol and 108 to placebo, and all randomly assigned patients received at least one dose. Six patients were excluded for site non-compliance, leaving a 315-patient full-analysis set for the efficacy analyses.

In the 315-patient full-analysis set, 293 participants were female and 22 were male. At week 48, 103 of 208 patients in the dapirolizumab pegol group achieved BICLA response, compared with 37 of 107 patients in the placebo group. This corresponded to rates of 50% and 35%, respectively. The between-group difference was 14.6 percentage points, with a 95% confidence interval of 3.3 to 25.8 and a p value of 0.011. The primary endpoint favored dapirolizumab pegol at week 48.

Safety analyses included all randomly assigned patients who received at least one dose of study medication. Treatment-emergent adverse events were reported in 83% of the dapirolizumab pegol group and 75% of the placebo group. Serious treatment-emergent adverse events occurred in 10% and 15%, respectively, while serious infections were reported in 4% and 6%. Infusion hypersensitivity reactions occurred in 3% of patients receiving dapirolizumab pegol, and one thromboembolic event, identified as myocardial infarction, was also reported in that group. One death from gangrene-related sepsis was reported in the active-treatment arm.