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MK-4646

Phase 1

HIV Infection | Small molecule | Infectious Disease |Merck & Company, Inc.|Trials Updated: Jun 22, 2026

MK-4646 development status

Highest phase Phase 1
Registered trials 3 across 1 sponsor since Jun 2025

Success Probability

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Market & Valuation

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Trial Design

RandomizedCONTROLLED
Total Trials1
Total Enrollment15

FDA Designations

No designations recorded

MK-4646 clinical trials

MK-4646 · 1 trial · 1 indication

Phase 1 1
NCT07042945MK-4646 Multiple Dose Trial in Participants With Human Immunodeficiency Virus Type 1 (HIV-1) (MK-4646-003)HIV Infection
COMPLETED15 Analytics
PHASE1COMPLETED
MK-4646 Multiple Dose Trial in Participants With Human Immunodeficiency Virus Type 1 (HIV-1) (MK-4646-003)
HIV InfectionUnlock trial analytics

Study Endpoints

Primary Endpoints

Participants with averse events (AEs)
14 days post last dose (Up to Day 23)

Percentage of participants with one or more AEs

Participants who discontinued study medication due to an AE
Up to Day 7

Percentage of participants who discontinued study medication due to an AE

Viral load decline of plasma HIV-1 ribonucleic acid (RNA)
Predose, 1,2, 3, 4 and 5 days postdose

Time course of plasma HIV-1 RNA viral load decline.

Secondary Endpoints

Area under the curve from time 0 to 24 hours (AUC0-24) of MK-4646
Predose, 0.5, 1, 2, 3, 4, 5, 6, 8, 12, 24 hours postdose
Maximum plasma concentration (Cmax) of MK-4646
Predose, 0.5, 1, 2, 3, 4, 5, 6, 8, 12, 24 hours postdose
Concentration at 24 hours (C24) of MK-4646
24 hours postdose
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Study Design & Arms

AllocationRANDOMIZED
MaskingNONE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
MK-4646 Panel AEXPERIMENTALMK-4646 160 mg every 24 hours (q24h) for 7 days
MK-4646 Panel BEXPERIMENTALMK-4646 ≤460 mg q24h for 7 days
MK-4646 Panel CEXPERIMENTALMK-4646 ≤460 mg q24h for 7 days
MK-4646 Panel DEXPERIMENTALMK-4646 ≤460 mg every 12 hours (q12h) for 7 days

Interventions

NameTypeDescription
MK-4646DRUGMK-4646 in capsular form administered orally
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Eligibility Criteria

Age Range18 Years to 60 Years
SexALL
Healthy VolunteersNo
Study Sites2

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...

Countries:MoldovaRomania
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Recent Changes (Last 90 Days)

MEDIUMJul 23, 2026NCT07042945TRIAL_REMOVED: changed
MEDIUMJul 23, 2026NCT07042945TRIAL_REMOVED: changed
MEDIUMJul 23, 2026NCT07042945TRIAL_REMOVED: changed

Frequently asked questions about MK-4646

What is MK-4646 used for?

MK-4646 is an investigational small molecule being studied for the treatment of HIV Infection, specifically Human Immunodeficiency Virus Type 1 (HIV-1). It is in Phase 1 clinical development and has not been approved for any indication. The completed Phase 1 trial enrolled adults aged 18 years and older living with HIV-1.

Who is developing MK-4646?

MK-4646 is being developed by Merck & Company, Inc., which trades on the New York Stock Exchange under the ticker MRK. Merck is the sponsor of the Phase 1 clinical program evaluating MK-4646 in participants with HIV-1 infection.

What phase is MK-4646 in?

MK-4646 is in Phase 1 clinical development. One Phase 1 trial has been completed, and no active trials are currently listed. The drug remains investigational and has not been approved by the FDA or any other regulatory agency for the treatment of HIV Infection.

What clinical trials is MK-4646 in?

MK-4646 has been evaluated in one completed Phase 1 trial, NCT07042945, titled MK-4646 Multiple Dose Trial in Participants With Human Immunodeficiency Virus Type 1 (HIV-1) (MK-4646-003). The trial enrolled 15 participants across Moldova and Romania, was randomized and controlled, and included adults aged 18 years and older.

Is MK-4646 the same as MK4646?

Yes, MK-4646 and MK4646 refer to the same investigational compound. MK-4646 is the hyphenated form of the name, while MK4646 is the unhyphenated form. Both names are used interchangeably in reference to the Merck HIV-1 candidate in Phase 1 development.