A Study of the Safety, Efficacy, and Biomarker Response of BMS-986165 in Participants With Moderate to Severe Ulcerative Colitis

Percentage of Participants in Clinical Response at Week 12

Clinical response is defined as achieving the following changes in the modified Mayo score (excludes the physicians' global assessment) * A decrease from baseline in the modified Mayo score of ≥ 2 points, and * A decrease from baseline in the modified Mayo score ≥ 30%, and * A decrease in rectal bleeding (RB) subscore of ≥ 1 point or absolute RB subscore ≤ 1 Note: The modified Mayo score calculated to determine eligibility will also be used as the baseline disease activity score. The modified Mayo score is a 9-point scale (a score of 5 to 9 points denotes moderate to severe disease). The modified Mayo score is a sum of the following 3 components: * Stool frequency (SF) subscore (0 to 3) * Rectal bleeding (RB) subscore (0 to 3) * Endoscopic (ES) subscore (0 to 3)

Time frame: At week 12

Number of Participants Experiencing Adverse Events (AEs)

An AE is defined as any new untoward medical occurrence or worsening of a preexisting medical condition in a clinical investigation participant administered study drug and that does not necessarily have a causal relationship with this treatment. Note: the first dose of study treatment in the open-label period may be the same as the last dose date of study treatment in double-blind treatment period, therefore, the participants analyzed in the open-label period may contain double blind participants finishing their last dose in the double-blind treatment period.

Time frame: From first dose up to the last dose in the double-blind period or 30 days post the last dose date if not treated in the open-label period and from the first dose in open-label period up to 30 days post the last dose date (up to approximately 402 days)

Number of Participants Experiencing Serious Adverse Events (SAEs)

An SAE is defined as any untoward medical occurrence that, at any dose: results in death, is life-threatening, requires inpatient hospitalization or causes prolongation of existing hospitalization, results in persistent or significant disability or permanent damage, is a congenital anomaly/birth defect, is an important medical event. Note: the first dose of study treatment in the open-label period may be the same as the last dose date of study treatment in double-blind treatment period, therefore, the participants analyzed in the open-label period may contain double blind participants finishing their last dose in the double-blind treatment period.

Time frame: From first dose up to the last dose in the double-blind period or 30 days post the last dose date if not treated in the open-label period and from the first dose in open-label period up to 30 days post the last dose date (up to approximately 402 days)

Number of Participants Experiencing Adverse Events (AEs) Leading to Discontinuation

An AE is defined as any new untoward medical occurrence or worsening of a preexisting medical condition in a clinical investigation participant administered study drug and that does not necessarily have a causal relationship with this treatment. Note: the first dose of study treatment in the open-label period may be the same as the last dose date of study treatment in double-blind treatment period, therefore, the participants analyzed in the open-label period may contain double blind participants finishing their last dose in the double-blind treatment period.

Time frame: From first dose up to the last dose in the double-blind period or 30 days post the last dose date if not treated in the open-label period and from the first dose in open-label period up to 30 days post the last dose date (up to approximately 402 days)

Number of Participants Experiencing Adverse Events of Special Interest (AEIs)

An AE is defined as any new untoward medical occurrence or worsening of a preexisting medical condition in a clinical investigation participant administered study drug and that does not necessarily have a causal relationship with this treatment. AEs of special interest include: skin events, influenza, herpes viral infections, opportunistic infections, tuberculosis, cardiovascular events, malignancy, and COVID-19.

Time frame: From first dose to 52 weeks after first dose