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Islatravir

Islatravir

Drug

Drug Profile

Islatravir is an antiviral agent in the nucleoside reverse transcriptase translocation inhibitor (NRTTI) class developed for HIV treatment. Clinical development has included standalone and fixed-dose combination programs, with a marketed doravirine/islatravir tablet approved in 2026. The active triphosphate metabolite inhibits reverse transcriptase with immediate and delayed chain-termination effects.

Drug Class: Nucleoside reverse transcriptase translocation inhibitor (NRTTI)
Approval Status: Present in FDA-approved combination product (Idvynso), first approved April 20, 2026.
Mechanism of Action: After phosphorylation to islatravir-triphosphate, inhibits reverse transcriptase by blocking translocation and preventing further nucleotide incorporation.

Brand Names

Idvynso

Indications

\HIV-1 infection in adults (as part of doravirine/islatravir complete regimen for virologically suppressed adults)\

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Related Clinical Trials

NCT ID	Title	Status	Phase
NCT06719570	A Study of Doravirine and Islatravir as a Single Entity or Combination Therapy and the Effect of Food in Healthy Adult Participants (MK-8591A-055)	COMPLETED	PHASE1
NCT06619678	A Study of MK-8507 and Islatravir (MK-8591) in Healthy Adult Participants (MK-8507-016)	COMPLETED	PHASE1
NCT05130086	A Study of Islatravir (MK-8591) in Trans and Gender Diverse Participants (MK-8591-035)	WITHDRAWN	PHASE2
NCT05115838	Radiopaque Matrix MK-8591 Implant in Participants at Low-Risk for Human Immunodeficiency Virus Type 1 (HIV-1) Infection (MK-8591-043)	WITHDRAWN	PHASE2
NCT04644029	Oral ISL QM as PrEP in Cisgender Women at High Risk for HIV-1 Infection (MK-8591-022)	TERMINATED	PHASE3
NCT04568603	Islatravir and Methadone Pharmacokinetics (MK-8591-029)	COMPLETED	PHASE1
NCT04564547	Dose Ranging, Switch Study of Islatravir (MK-8591) and Ulonivirine (MK-8507) Once-Weekly in Virologically-Suppressed Adults With Human Immunodeficiency Virus Type 1 (HIV-1) [MK-8591-013]	COMPLETED	PHASE2
NCT04515641	Single-Dose Islatravir in Moderate Hepatic Impairment (MK-8591-030)	COMPLETED	PHASE1
NCT04303156	Pharmacokinetics of Islatravir in Participants With Severe Renal Impairment (MK-8591-026)	COMPLETED	PHASE1
NCT04003103	Safety and Pharmacokinetics of Oral Islatravir (MK-8591) Once Monthly in Participants at Low Risk of Human Immunodeficiency Virus 1 (HIV-1) Infection (MK-8591-016)	COMPLETED	PHASE2