Core Insights - AnaptysBio, Inc. announced positive late-breaking data from a Phase 2b trial of rosnilimab for rheumatoid arthritis, showing durable clinical benefits and a favorable safety profile [1][4][5] Group 1: Trial Overview - The Phase 2b RENOIR trial involved 424 patients with moderate-to-severe rheumatoid arthritis, assessing the efficacy, safety, and tolerability of rosnilimab [3][4] - Patients were either naïve to biologic or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) or had prior treatment experience [3][6] Group 2: Efficacy Results - Positive results were observed at Week 12, with significant efficacy on primary endpoints such as DAS28-CRP and ACR20 across all doses [5] - By Week 28, clinical responses continued to improve, including CDAI remission and ACR50/70 rates, regardless of prior treatments [4][5] - Durable clinical benefits were confirmed for at least three months off drug, with significant reductions in Tph cells by over 90% [4][5] Group 3: Safety Profile - Rosnilimab was well-tolerated throughout the trial, with no treatment-related serious adverse events or malignancies reported [1][4][5] - The trial demonstrated a low dropout rate and no safety trends similar to those seen with JAK inhibitors or other biologics [2][4] Group 4: Mechanism of Action - Rosnilimab targets pathogenic T cells, effectively depleting them while sparing nonpathogenic T cells, which helps maintain overall immune function [8][9] - The drug's mechanism was validated by significant reductions in T cell and B cell activation in synovial biopsies [5]