The main purpose of this study is to evaluate the long-term safety and efficacy of the drug Deucravacitinib (BMS-986165) in participants who have been previously enrolled in an applicable Phase 3 psoriasis study. In addition, the study includes a vaccine cohort to evaluate whether deucravacitinib impacts the humoral immune response to 2 non-live vaccines, the Pneumovax 23 vaccine (pneumococcus), a T-cell independent vaccine, and the Boostrix vaccine (tetanus toxoid), a T-cell dependent vaccine. Additionally, this vaccine cohort assesses the safety of administering these vaccines to subjects with psoriasis receiving deucravacitinib compared to those receiving a placebo.

Inclusion Criteria

• Completion of the protocol-required treatment period in an applicable study of BMS-986165 in moderate-to-severe psoriasis.

• Women must not be pregnant, lactating, or breastfeeding.

• Vaccine Cohort:

  1. Subject must have moderate-to-severe plaque psoriasis, be currently receiving deucravacitinib treatment in the main IM011075 LTE cohort in the United States, Canada, or Poland, and must have completed at least one year of deucravacitinib treatment.

Exclusion Criteria

• Any disease or medical condition that the investigator feels that would make the patient unsuitable for this study.

• To be eligible for the study, a participant must not have active signs or symptoms of tuberculosis (TB) as judged by the investigator.

• Vaccine Cohort:

  1. Subject received the Pneumovax 23 vaccine ≤ 5 years before Day 1 or a pneumococcal conjugate vaccine ≤ 1 year before Day 1.
  2. Subject received the Boostrix vaccine (as single or part of a combination vaccine) ≤ 5 years before Day 1.

• Other protocol-defined inclusion/exclusion criteria apply