Study to evaluate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD), and effects on low-density lipoprotein cholesterol (LDL-C) and triglycerides (TGs) of single-dose ARO-DIMERPA and multiple doses of ARO-DIMERPA in adult participants with mixed hyperlipidemia.

Inclusion Criteria:

• Willing to follow diet counseling as per Investigator judgment based on local standard of care
• Specific fasting TG, LDL-C, and non-high density lipoprotein cholesterol levels at Screening
• Participants of childbearing potential must agree to use highly effective contraception in addition to a condom during the study and for at least 90 days following the end of the study or last dose of study drug, whichever is later; participants must not donate sperm or eggs during the study and for at least 90 days following the end of the study or last dose of study drug whichever is later

Exclusion Criteria:

• Current use or use within last 365 days or within 5-half-lives before Day 1 based on plasma PK, whichever is longer, of any hepatocyte-targeted siRNA
• Current use or use within last 90 days or within 5-half-lives before Day 1 based on plasma PK, whichever is longer, of any antisense oligonucleotide therapy
• Current use or use within last 60 days from Day 1 of any PCSK9 inhibitor monoclonal antibodies (eg, evolocumab or alirocumab)
• Uncontrolled hypertension
• History of bleeding diathesis or coagulopathy
• Current diagnosis of nephrotic syndrome

Note: Additional inclusion/exclusion criteria may apply per protocol.