June 29, 2026--RAHWAY, N.J.--(BUSINESS WIRE)-- Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced an agreement with the ADAP Crisis Task Force (ACTF) to help state AIDS Drug Assistance Programs (ADAPs) provide access to the company’s new once-daily HIV treatment, IDVYNSO™ (doravirine/islatravir). In 2024, state ADAPs supported more than 250,000 people with HIV in the United States.
IDVYNSO was approved by the U.S. Food and Drug Administration (FDA) in April 2026 as a new, two-drug single-tablet regimen of 100 mg doravirine and 0.25 mg islatravir, for the treatment of HIV-1 infection in adults to replace the current antiretroviral regimen in those who are virologically suppressed (HIV-1 RNA less than 50 copies per mL) on a stable antiretroviral regimen with no history of virologic treatment failure and no known substitutions associated with resistance to doravirine.
“ADAP programs play a critical role in supporting access to treatment for people living with HIV who are uninsured or underserved,” said Tim Horn, Director, Medication Access, National Alliance of State and Territorial AIDS Directors (NASTAD). “We appreciate Merck’s continued engagement and its willingness to work collaboratively to help address the critical access challenges facing state ADAP programs.”
“Merck is pleased to have reached this agreement with the ADAP Crisis Task Force to expand access to IDVYNSO for eligible people with HIV,” said Conrod Kelly, U.S. HIV business unit head, Merck. “This agreement reflects our long-standing commitment to working with the ACTF, state ADAPs and the HIV community to strengthen access and help address persistent gaps in care.”
For individuals with questions about coverage and affordability, the Merck Access Program may be able to provide information about insurance benefits, estimated out-of-pocket costs and co-pay assistance options for eligible patients.
The Merck Access Program for IDVYNSO
Merck offers support to individuals who are prescribed IDVYNSO, including information about patient insurance coverage and out-of-pocket costs, co-pay assistance for eligible, commercially insured individuals, and how individuals may access IDVYNSO through The Merck Access Program. For additional information, healthcare providers and individuals can call 1-877-709-4455 or visit https://www.merckaccessprogram-idvynso.com/.
About IDVYNSO
IDVYNSO is a fixed-dose combination of two medicines, doravirine and islatravir. Doravirine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that inhibits HIV-1 replication by non-competitive inhibition of HIV-1 reverse transcriptase. Islatravir is a potent, next-generation nucleoside analog reverse transcriptase inhibitor (NRTI) that blocks HIV-1 replication by multiple mechanisms including:
inhibition of reverse transcriptase translocation, resulting in immediate chain termination, and
induction of structural changes in the viral DNA (delayed chain termination).
Merck’s Commitment to HIV
For 40 years, Merck has been committed to scientific research and discovery in HIV leading to scientific breakthroughs that have helped change HIV treatment. Our work has helped pioneer the development of new options across multiple drug classes to help those impacted by HIV. Today, we are developing a series of antiviral options designed to help people manage HIV and protect people from HIV. We are researching for real life and want to ensure people are not defined by HIV. Our work focuses on transformational innovations, collaborations with others in the global HIV community and access initiatives aimed at helping to end the HIV epidemic for everyone.
About Islatravir (MK-8591) and Merck’s HIV Research
Islatravir (MK-8591) is Merck’s potent, next-generation nucleoside analog reverse transcriptase inhibitor (NRTI) that blocks HIV-1 replication by multiple mechanisms including inhibition of reverse transcriptase translocation, resulting in immediate chain termination, and induction of structural changes in the viral DNA (delayed chain termination).
Islatravir is approved in combination with Merck’s NNRTI, doravirine, in the United States and Japan as IDVYNSO™, a once-daily, single-tablet regimen for the treatment of HIV-1 infection in adults to replace the current antiretroviral regimen in those who are virologically suppressed (HIV-1 RNA less than 50 copies per mL) on a stable antiretroviral regimen with no history of virologic treatment failure and no known substitutions associated with resistance to doravirine.
Islatravir is also under evaluation in multiple ongoing early and late-stage clinical trials in combination with other antiretrovirals for potential once-weekly treatments for HIV-1, in Merck's proprietary two-drug regimens.
Islatravir in combination with Gilead’s lenacapavir is in Phase 3 development as a novel oral once-weekly treatment for HIV-1 [ISLEND-1 (NCT06630286) and ISLEND-2 (NCT06630299)], and islatravir in combination with Merck’s investigational non-nucleoside reverse transcriptase inhibitor (NNRTI) ulonivirine (MK-8507) is in Phase 2b development (MK-8591B-060, NCT06891066 and MK-8591B-062, NCT07266831) as an oral once-weekly treatment.
MK-8527 is Merck’s investigational, novel, once-monthly, oral candidate for pre-exposure prophylaxis (PrEP) for HIV-1. In collaboration with the Gates Foundation, the Phase 3 EXPrESSIVE-10 trial (MK-8527-010, NCT07071623) trial is evaluating the safety and efficacy of MK-8527 as PrEP to reduce the risk of sexually acquired HIV-1 infection among women and adolescent girls in sub-Saharan Africa. The Phase 3 EXPrESSIVE-11 trial (MK-8527-011, NCT07044297) in 16 countries is evaluating the safety and efficacy of MK-8527 as PrEP to reduce the risk of sexually acquired HIV-1 infection among people likely to be exposed to HIV-1. Both trials are now enrolling.
About Merck
At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities.