An Early-Stage Study in Multiple Clinics of How Afimkibart May Affect the Body's Processing of Medicines That Rely on Cytochrome P450 Enzymes in Participants With Ulcerative Colitis

A Phase I, Multicenter, Open-Label, Single-Agent Study to Assess the Pharmacokinetics of Cytochrome P450 Substrates After Treatment With Afimkibart in Participants With Moderately to Severely Active Ulcerative Colitis

The purpose of this study is to evaluate the disease-drug-drug interaction (DDDI) potential of afimkibart (also known as RO7790121). This will be assessed by the characterization of the pharmacokinetics (PK) of cytochrome P450 (CYP) enzyme substrates alone and after administration of afimkibart in participants with moderately to severely active ulcerative colitis (UC).

Inclusion Criteria:

• Body weight >= 40kg
• Agreement to adhere to the contraceptive requirements

UC Specific Inclusion Criteria:

• Confirmed diagnosis of UC with supportive clinical, endoscopic, and histopathological evidence
• Active UC confirmed by endoscopy (flexible sigmoidoscopy or colonoscopy) extending >=15 cm from the anal verge
• Moderately to severely active UC, defined as an modified Mayo score of 5 to 9 points, including a Mayo endoscopic subscore of 2 or 3, confirmed through centrally read endoscopy

Exclusion Criteria:

Inflammatory Bowel Disease (IBD) Exclusion Criteria:

• Current diagnosis of Crohn's disease (CD),abdominal/intrabdominal/perianal fistula and/or abscess, indeterminant colitis, IBD-unclassified, microscopic colitis, ischemic colitis, infectious colitis, radiation colitis, or active diverticular disease
• Presence of an ostomy or ileoanal pouch
• Current diagnosis or suspicion of primary sclerosing cholangitis

Medical History Exclusion Criteria:

• Lack of peripheral venous access
• Any major surgery within 6 weeks prior to screening or a major surgery planned during the study
• History of alcohol, drug, or chemical abuse < 1 year prior to screening