State ADAP programs are a cornerstone of the U.S. HIV care infrastructure, serving more than 250,000 people in 2024. Through the new agreement, participating ADAPs will be better positioned to offer Idvynso to appropriate patients, helping to address ongoing challenges related to treatment access and continuity of care.

FDA Approval of Idvynso

The U.S. Food and Drug Administration approved Idvynso in April 2026 as a once-daily, single-tablet regimen combining 100 mg of doravirine and 0.25 mg of islatravir. The therapy is intended for adults with HIV-1 who have already achieved viral suppression and are stable on an existing antiretroviral regimen. Candidates for treatment should have no history of virologic treatment failure and no known resistance-associated mutations affecting doravirine.

As a two-drug regimen, Idvynso offers a simplified treatment option for virologically suppressed patients seeking to maintain long-term HIV control with a single daily tablet.

Focus on Access and Affordability

The agreement has been welcomed by HIV advocacy organizations. Tim Horn, Director of Medication Access at the National Alliance of State and Territorial AIDS Directors (NASTAD), highlighted the essential role ADAPs play in ensuring treatment availability for vulnerable populations. He noted that collaboration between pharmaceutical manufacturers and state programs is increasingly important as ADAPs navigate ongoing funding and access pressures.

Merck emphasized that the partnership reflects its long-standing efforts to work with ACTF, state ADAP administrators, and the broader HIV community to reduce barriers to care.

To further support patients, the company is offering assistance through the Merck Access Program, which provides information on insurance coverage, estimated out-of-pocket expenses, and financial assistance options. Eligible commercially insured patients may also qualify for co-pay support.

How Idvynso Works

Idvynso combines two antiretroviral agents with complementary mechanisms of action:

• Doravirine, a non-nucleoside reverse transcriptase inhibitor (NNRTI), blocks HIV replication by targeting the virus’s reverse transcriptase enzyme.
• Islatravir, a next-generation nucleoside reverse transcriptase inhibitor (NRTI), suppresses HIV through multiple pathways, including interrupting reverse transcriptase activity and causing structural alterations in viral DNA that prevent successful viral replication.

The combination is designed to maintain viral suppression while reducing pill burden for eligible patients.

Merck’s Broader HIV Pipeline

The ACTF agreement comes as Merck continues to expand its HIV research portfolio. The company has been active in HIV drug development for four decades and is pursuing several next-generation treatment and prevention strategies.

Among the most advanced programs is the development of once-weekly oral HIV treatment regimens. Islatravir is currently being studied in combination with Gilead Sciences’ lenacapavir in two phase 3 clinical trials evaluating a weekly oral treatment approach. Merck is also investigating a weekly regimen pairing islatravir with its experimental NNRTI ulonivirine (MK-8507) in phase 2b studies.

Beyond treatment, Merck is developing MK-8527, an investigational once-monthly oral medication for HIV pre-exposure prophylaxis (PrEP). The candidate is being evaluated in two ongoing phase 3 studies, including one conducted in collaboration with the Gates Foundation. These trials are assessing its potential to reduce the risk of sexually acquired HIV infection among women, adolescent girls, and other populations at increased risk of exposure.

Looking Ahead

The new agreement between Merck and ACTF highlights the growing emphasis on improving treatment accessibility alongside pharmaceutical innovation. As newer therapies such as Idvynso enter the market, partnerships between manufacturers, advocacy groups, and public assistance programs will remain critical to ensuring that advances in HIV care reach the patients who need them most.