The aim of this study is to measure the concentration levels of mezigdomide in the blood of participants with mild, moderate, and severe hepatic impairment, and in matched healthy control participants with normal hepatic function.

Inclusion Criteria:

Hepatic Impaired Participants:

• Participants have mild, moderate, or severe hepatic impairment or cirrhosis due to chronic hepatic disease and/or prior alcohol use.
• Participants have mild (Group A), moderate (Group B), or severe (Group C) hepatic impairment as defined by Child-Pugh Score.

Matched Healthy Participants:

• Participant must be free of any clinically significant disease that would interfere with the study evaluations.
• Participant must have liver-related laboratory test results within the respective reference ranges or with clinically insignificant excursions therefrom as agreed by the investigator.

Exclusion Criteria:

All Participants:

• History of chronic pruritus or dermatologic syndromes that may be confounded with reactions to mezigdomide.
• Contraindication or intolerance to first-generation antihistamine medications.

Hepatic Impaired Participants:

-Clinical laboratory test results:

• Platelet count lower than 30,000/microliter (μL) at screening or Day -1.
• Absolute neutrophil counts lower than 1,500/μL at screening or Day -1.

Matched Healthy Participants:

-History of or suspected benign ethnic neutropenia.

Other protocol-defined inclusion/exclusion criteria apply

BMS will provide access to individual anonymized participant data upon request from qualified researchers, and subject to certain criteria. Additional information regarding Bristol Myers Squibb's data sharing policy and process can be found at: https://www.bms.com/researchers-and-partners/clinical-trials-and-research/disclosurecommitment.html