A Study of Efficacy and Safety of Rosnilimab in Subjects With Moderate to Severe Ulcerative Colitis (ROSETTA)

Male or female ≥18

Participants with a clinical diagnosis of UC for prior to Day 1

Subject has moderate to severe, active UC, defined as a mMS ≥ 5 with an endoscopy subscore ≥2

Subject has had a surveillance colonoscopy that did not detect potential dysplasia or colon cancer performed within 1 year of Day 1.

Subject has a diagnosis of Crohn's disease or indeterminate colitis.

Subject has a diagnosis of fulminant colitis and/or toxic megacolon.

Subject has a history of an inadequate response, loss of response, or intolerance to any combination of 3 or more advanced UC therapy classes but not limited to, 1) anti-TNF antibodies (e.g., adalimumab, golimumab, infliximab), 2) other biologics (e.g., ustekinumab, vedolizumab), 3) oral JAK inhibitors (e.g., tofacitinib, upadacitinib), and 4) oral S1P receptor modulators (e.g., ozanimod).

Subject has disease limited to the rectum (ulcerative proctitis)

Subject has a history of colectomy (total or subtotal), ileoanal pouch, Kock pouch, or ileostomy or is planning bowel surgery.

The subject had prior exposure to a PD-1 or PD-L1 agonist, antagonist, or modulator.