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# AnaptysBio Reports Positive Data on Arthritis Drug
- URL: https://www.fdaweb.com/anaptysbio-reports-positive-data-on-arthritis-drug/
- Published: 2025-02-12T12:00:00.000Z
- Updated: 2026-09-14T14:52:59.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5158651

AnaptysBio is reporting positive data from a Phase 2 study of rosnilimab for treating moderate-to-severe rheumatoid arthritis (RA). The 424-patient Phase 2b RENOIR trial achieved its primary endpoint of the mean change from baseline in its disease activity score at Week 12 for all three doses of rosnilimab vs. placebo, the company says. Rosnilimab also achieved statistical significance in at least one dose and numerical superiority at all doses, including once monthly administration, on key secondary endpoints of ACR20 (at least a 20% improvement in the number of tender and swollen joints), ACR50 and CDAI (clinical disease activity index) at Week 12, even though higher than typical placebo rates were observed, it says.

Rosnilimab is described by AnaptysBio as a novel therapeutic antibody that directly targets PD-1, a co-inhibitory receptor preferentially expressed on the surface of activated T cells, which broadly impacts the pathogenic drivers of inflammatory diseases such as RA. It is designed to deplete PD-1 (high) T cells and agonize the remaining PD-1+ T cells to restore the immune system back to a state of homeostasis, it says.