A Study to Evaluate the Pharmacokinetics, Safety, and Pharmacodynamics of Olpasiran in Participants With Various Degrees of Hepatic Impairment

The primary objective of the study is to evaluate the pharmacokinetics (PK) of a single dose of olpasiran in participants with mild, moderate, or severe hepatic impairment compared to participants with normal hepatic function.

Inclusion Criteria: * Male or female participants of nonchildbearing potential, between 18 and 75 years of age (inclusive) at the time of Screening. * Body mass index between 18.0 and 40.0 kg/m\^2 (inclusive) at the time of Screening. Participants with Normal Hepatic Function Only: • In good health, determined by no clinically significant findings from medical history, physical examination, 12-lead ECG, vital signs measurements, and clinical laboratory evaluations at Screening and Check-in as assessed by the Investigator (or designee). Participants with Hepatic Impairment Only: • Child-Pugh A (Group 2), B (Group 3), or C (Group 4) classification defined by both Screening (to determine participant group) and Check-in (to confirm participant group prior to dosing) clinical laboratory values and physical examination findings. Exclusion Criteria: * History of significant hypersensitivity, intolerance, or allergy to any drug compound, food, or other substance, unless approved by the Investigator (or designee). * Estimated glomerular filtration rate \< 60 mL/min/1.73m\^2 (Groups 1-3) or \< 50 mL/min/1.73m\^2 (Group 4 only) by Modification of Diet in Renal Disease formula at Screening or Check-in. * Receiving or has received any investigational drug within the 30 days or 5 half-lives (whichever is longer) before receiving olpasiran. * Participants who were previously exposed to olpasiran. * Female participants with a positive pregnancy test at Screening or Check-in. Participants with Normal Hepatic Function Only: * Positive hepatitis panel. Participants whose results are compatible with prior immunization may be included. * Alanine aminotransferase and aspartate aminotransferase elevations \> 3x upper limit of normal at Screening or Check-in. Participants with Hepatic Impairment Only: * Positive for hepatitis B surface antigen. Participants with positive hepatitis B core antibody may be included if hepatitis B surface antigen is negative. Participants with positive hepatitis B surface antibody may be included (consistent with prior vaccination). * Active malignancy of any type. Participants with a history of malignancy that has been eradicated with supporting medical documentation indicating that there is no residual malignancy detected in the past 2 years will be allowed. * Values outside the normal range for liver function tests that are not consistent with their hepatic condition, as determined by the Investigator (or designee).