A Phase 2 Trial of Peresolimab for Adults with Rheumatoid Arthritis

BACKGROUND Peresolimab is a humanized IgG1 monoclonal antibody designed to stimulate the endogenous programmed cell death protein 1 (PD-1) inhibitory pathway. Stimulation of this pathway would be a novel approach to the treatment of patients with autoimmune or autoinflammatory diseases. METHODS In this phase 2a, double-blind, randomized, placebo-controlled trial, we assigned, in a 2:1:1 ratio, adult patients with moderate-to-severe rheumatoid arthritis who had had an inadequate response to, a loss of response to, or unacceptable side effects with conventional synthetic disease-modifying antirheumatic drugs (DMARDs) or to biologic or targeted synthetic DMARDs to receive 700 mg of peresolimab, 300 mg of peresolimab, or placebo intravenously once every 4 weeks. The primary outcome was the change from baseline to week 12 in the Disease Activity Score for 28 joints based on the C-reactive protein level (DAS28-CRP). The DAS28-CRP ranges from 0 to 9.4, with higher scores indicating more severe disease. The primary comparison was between the 700-mg group and the placebo group. Secondary outcomes included the percentages of patients with American College of Rheumatology 20 (ACR20), ACR50, and ACR70 responses - defined as improvements from baseline of 20%, 50%, and 70% or more, respectively, in the numbers of tender and swollen joints and in at least three of five important domains - at week 12. RESULTS At week 12, the change from baseline in the DAS28-CRP was significantly greater in the 700-mg peresolimab group than in the placebo group (least-squares mean change [+/- SE], -2.09 +/- 0.18 vs. -0.46 +/- 0.26; difference in change, -1.09 [95% confidence interval, -1.73 to 0.46]; P<0.001). The results of the analyses of secondary outcomes favored the 700-mg dose over placebo with respect to the ACR20 response but not with respect to the ACR50 and ACR70 responses. Adverse events were similar in the peresolimab and placebo groups. CONCLUSIONS Peresolimab showed efficacy in a phase 2a trial in patients with rheumatoid arthritis. These results provide evidence that stimulation of the PD-1 receptor has potential efficacy in the treatment of rheumatoid arthritis.