A Study to Learn How the Body Processes BIIB141 (Omaveloxolone) When Taken as a Capsule or as a Tablet Dissolved in Liquid, and to Learn About Its Safety in Healthy Adults Ages 18 to 55

The primary objective of the study is to assess the bioequivalence (BE) of omaveloxolone tablets for oral suspension (TOS) compared to capsules in healthy adult participants. The secondary objective of the study is to assess the safety and tolerability of a single dose of omaveloxolone when administered as TOS or capsule in healthy adult participants.

Key Inclusion Criteria:

• All female participants of childbearing potential must have negative results for pregnancy tests as follows:

• At screening, based on a serum sample obtained within 28 days prior to initial study drug administration; and
• Prior to dosing, based on a serum sample obtained on Study Day -1.
• Body Mass Index (BMI) at screening between 18 and 32 kilograms per meter square (kg/m^2), inclusive.
• Participants must be in good health.

Key Exclusion Criteria:

• History of any clinically significant cardiac, endocrine, gastrointestinal, hematologic, hepatic, immunologic, metabolic, urologic, pulmonary, neurologic, dermatologic, psychiatric, or renal disease, or other major disease, as determined by the Investigator.
• Clinically significant, as determined by the Investigator, 12-lead electrocardiogram (ECG) abnormalities.
• History of, or positive test result for human immunodeficiency virus (HIV).
• History of hepatitis C infection or positive test result at Screening for hepatitis C virus antibody (HCV Ab).
• Current hepatitis B infection [defined as positive for hepatitis B surface antigen (HBsAg) and/or total hepatitis B core antibody (anti-HBc)]. Participants with immunity to hepatitis B from previous natural infection (defined as negative HBsAg, positive anti-HBc, and positive anti-HBs) or vaccination (defined as negative HBsAg, negative anti-HBc, and positive anti-HBs) are eligible to participate in the study.
• Chronic, recurrent, or serious infection (e.g., pneumonia, septicemia), as determined by the Investigator, within 90 days prior to Screening or between Screening and Day -1.
• Prior exposure to the study treatment.
• Any clinically significant abnormal laboratory test value as determined by the Investigator, as Screening or Day-1.

NOTE: Other protocol-defined Inclusion/Exclusion criteria may apply.