Anaptys Announces Rosnilimab Achieved Positive Results in RA Phase 2b Trial and Highest Ever Reported CDAI LDA Response Over 6 Months

• Achieved statistical significance on primary endpoint at Week 12 on mean change from baseline DAS-28 CRP across all rosnilimab doses vs. placebo
• Achieved statistical significance on key secondary endpoints at Week 12 on ACR20, ACR50 and CDAI LDA
• Demonstrated highest ever reported responses on key secondary endpoints at Week 14 on ACR20, ACR50, ACR70 and CDAI LDA
• 69% of rosnilimab-treated patients achieved CDAI LDA at Week 14 and appear to show sustained CDAI LDA and ACR50 responses and potentially deepening ACR70 responses out to Week 28
• Robust pharmacological activity observed in reduction of PD-1high T cells, increase in total Tregs and reduction of CRP across all doses
• Rosnilimab was safe and well tolerated with similar adverse event rates vs. placebo
• Full Week 28 and additional translational RA data in Q2 2025
• Top-line Week 12 Phase 2 ulcerative colitis data for rosnilimab, now in Q4 2025
• Conference call and webcast to discuss results today at 8:30am ET

SAN DIEGO, Feb. 12, 2025 (GLOBE NEWSWIRE) -- AnaptysBio, Inc. (Nasdaq: ANAB), a clinical-stage biotechnology company focused on delivering innovative immunology therapeutics, today announced statistically significant Week 12 data from the global 424-patient Phase 2b RENOIR trial of investigational rosnilimab, a depleter and agonist of PD-1+ T cells, for moderate-to-severe rheumatoid arthritis (RA). Rosnilimab was safe and well tolerated with similar adverse event rates vs. placebo.

The Phase 2b RENOIR trial is evaluating the efficacy, safety, tolerability, pharmacokinetics and pharmacodynamics of rosnilimab in patients with moderate-to-severe RA on background conventional disease-modifying antirheumatic drugs (cDMARDs) (e.g., methotrexate). The trial enrolled 424 patients with a mean baseline disease activity score -- 28 joints (DAS-28) C-Reactive Protein (CRP) score of 5.64 and mean baseline clinical disease activity index (CDAI) score of 37.7 across the U.S., Canada and Europe, who were either biologic or targeted synthetic DMARD (b/tsDMARD) naïve (n=250; 59%) or experienced (n=174; 41%). Patients classified as b/tsDMARD-experienced reported prior utilization of at least one biologic or targeted synthetic therapy, such as TNFα inhibitors, B cell inhibitors, selective costimulatory modulators or JAK inhibitors.

Patients were randomized to receive either 100mg of subcutaneous rosnilimab every four weeks (Q4W), 400mg Q4W, 600mg every two weeks (Q2W), or placebo. The primary endpoint was assessed at Week 12 and secondary endpoints were assessed at both Week 12 and Week 14. Following completion of the Week 14 visit, rosnilimab-treated patients who achieved CDAI low disease activity (LDA) of ≤ 10, continued their assigned treatment through Week 28 in a blinded, all-active treatment period.

Rosnilimab Achieved Primary and Secondary Efficacy Endpoints

The trial achieved its primary endpoint of the mean change from baseline in DAS-28 CRP at Week 12 for all three doses of rosnilimab vs. placebo.

Rosnilimab achieved statistical significance in at least one dose and numerical superiority at all doses, including once monthly administration, on key secondary endpoints of ACR20, ACR50 and CDAI LDA at Week 12, even though higher than typical placebo rates were observed. Also, rosnilimab demonstrated the highest ever reported responses for these key secondary endpoints at Week 14. 69% of rosnilimab-treated patients achieved CDAI LDA at Week 14 and appear to show sustained CDAI LDA and ACR50 responses, as well as potentially deepening ACR70 responses out to Week 28.

Translational blood biomarker data, across all doses, showed similar immunological impact with robust on-target pharmacological activity in rosnilimab-treated patients that was not observed on placebo. Rosnilimab demonstrated rapid and sustained reduction of ~90% PD-1high T cells and ~50% of PD-1+ T cells, and an increase in total Tregs. Together, this resulted in a minimal impact on total T cell counts and favorable T cell composition reflective of healthy immune homeostasis. Additionally, a ~50% reduction in the mean CRP from baseline, an objective measure of inflammation, was observed in rosnilimab-treated patients through the entire trial period that was not observed on placebo.

“We are excited about these trial results and the impact they could have on patients living with RA. Rosnilimab is safe and well tolerated with the highest ever reported CDAI low disease activity at ~3 months that, to date, is sustained and potentially deepening over 6 months. These findings, further supported by objective translational data, surpass our target product profile in the ~$20 billion U.S. RA market,” said Daniel Faga, president and chief executive officer of Anaptys. “In Q2 2025, we will report full six-month data and additional translational data that we expect will further substantiate rosnilimab’s impact on restoring healthy immune homeostasis in RA and additional diseases, such as ulcerative colitis (UC). We also look forward to reporting top-line Week 12 Phase 2 data for rosnilimab in UC, now in Q4 2025.”

Results for trial endpoints at Week 12 and Week 14 were as follows: