The principal aim of this study is to obtain safety and tolerability data when MRT-8102 is administered orally as single and multiple doses to healthy participants and participants at cardiovascular risk with elevated CRP. This information, together with the pharmacokinetic (PK) data, will help establish the dose and dosing regimen suitable for future studies.

The study drug, MRT-8102, is experimental. This is the first study in which MRT-8102 will be given to humans.

Part 1: Healthy participants will receive a single oral dose of MRT-8102 or placebo on Day 1

Part 2: Healthy participants will receive multiple oral doses of MRT-8102 or placebo for 7 consecutive days

Part 3: Participants at cardiovascular risk with elevated CRP will receive multiple oral doses of MRT-8102 or placebo for 28 consecutive days

The purpose of this study is to:

• Learn about the safety and tolerability of single and multiple ascending oral doses of MRT-8102 in healthy adult participants
• Learn about the safety and tolerability of 28-day daily dosing of MRT-8102 in participants at cardiovascular risk with elevated CRP

Eligibility Criteria:

Inclusion Criteria (all parts)

• Healthy, adult, male or females 18-65 years of age
• Non-smoker who has not used nicotine- and tobacco -containing products for at least 3 months prior to start of study
• Able to swallow oral medications
• Abstain from caffeine- and methylxanthine-containing beverages or food

Parts 3: Inclusion Criteria

• Elevated CRP value ≥3.0 mg/L at the time of screening
• Evidence of cardiovascular risk factors
• No signs or symptoms of acute disease
• No ECG finding of clinical significance

Exclusion Criteria (All Parts)

• History or presence of clinically significant medical or psychiatric condition or disease
• Underwent surgical intervention or an operation withing 6 weeks prior to start of study
• Has active TB, latent TB, a history of TB, or had close contact with a person with active TB within 8 weeks prior to the first dosing
• Pregnant, breastfeeding, or planning a pregnancy or fathering a child during the study or within 3 months after the last study drug administration.
• Positive urine drug or alcohol screen results
• Positive results for human immunodeficiency virus (HIV), hepatitis B or Hepatitis C virus or history of resolved hepatitis
• Participation in another clinical study within 30 days or within 5 half-live (if known) prior to start of study
• Currently receiving other immunomodulators
• History of immunodeficiency, chronic inflammatory and chronic inflammation