MK-4646 Multiple Dose Trial in Participants With Human Immunodeficiency Virus Type 1 (HIV-1) (MK-4646-003)

This study will examine if at least one dose level of MK-4646 can lower HIV-1 viral load in a person's blood by a certain amount. The goals of this study are to learn about the safety of MK-4646 and if people tolerate it; and how HIV-1 viral load may decrease after starting to take MK-4646.

Inclusion Criteria: * Other than having HIV-1, is in good health * Is antiretroviral therapy (ART)-naïve * If ART-experienced has not received any antiretroviral therapy within 60 days (or 5 half-lives, whichever is longer) prior to screening * Is willing to receive no other ART prior to Day 8 post-dose of the trial * If capable of producing sperm agrees to use contraception * If assigned female sex at birth is not breastfeeding * A participant of childbearing potential (POCBP) is not pregnant and has a negative highly sensitive pregnancy test (urine or serum), and uses a contraceptive method that is highly effective Exclusion Criteria: * Has acute (primary) HIV-1 infection * Has history of clinically significant endocrine, gastrointestinal (GI), cardiovascular, hematological, hepatic, immunological, renal, respiratory, genitourinary, or major neurological (including stroke and chronic seizures) abnormalities or diseases * Is mentally or legally incapacitated, has significant emotional problems at the time of prestudy (screening) visit or expected during the conduct of the study or has a history of clinically significant psychiatric disorder of the last 5 years. * Has history of cancer (malignancy) * Has history of significant multiple and/or severe allergies * Tests positive for hepatitis B surface antigen (HBsAg), hepatitis C antibodies * Has had a major surgery and/or donated or lost 1 unit of blood (approximately 500 mL) within 4 weeks prior to the prestudy (screening) visit * Has received any vaccine starting from 30 days prior to study intervention or is scheduled to receive any vaccine through 14 days following study intervention * Is unable to refrain from using protocol specified prohibited medications * Is an excessive smoker, or consumes excessive amounts of alcoholic or caffeinated beverages * Is a regular user of any illicit drugs or has a history of drug (including alcohol) abuse