RecruitingPhase 1Drug trialAn 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 ColitisThe 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).