AnaptysBio said it will discontinue development of PD‑1 agonist rosnilimab in ulcerative colitis after a Phase 2 study missed primary and key secondary endpoints; remission rates at week 12 were lower than placebo in the tested doses. The company noted rosnilimab was safe and well tolerated but lacked sufficient efficacy to meet its six‑month target product profile. AnaptysCEO Daniel Faga said the decision conserves capital and allows focus on other programs, including a CD122 antagonist (ANB033) in Phase 1b. The company plans to spin into two public entities next year — one holding clinical assets and another managing royalty agreements. The failure underscores therapeutic risk for PD‑1 agonists in inflammatory bowel disease and will require Anaptys to seek new funding or strategic partnerships to advance remaining assets.