FDA approves Merck’s IDVYNSO™, a once-daily, two-drug regimen for virologically suppressed adults with HIV-1, supported by Phase 3 data showing non-inferior efficacy.
Written By: Nikita Jha, BPharm
Reviewed By: Pharmacally Editorial Team
The U.S. Food and Drug Administration has approved IDVYNSO™, a once-daily, single-tablet regimen developed by Merck for the treatment of HIV-1 infection in virologically suppressed adults.
The therapy is indicated for patients with HIV-1 RNA levels below 50 copies/mL who are stable on an existing antiretroviral regimen, with no history of treatment failure or resistance to doravirine. IDVYNSO combines doravirine, a non-nucleoside reverse transcriptase inhibitor, with islatravir, a next-generation nucleoside reverse transcriptase inhibitor. It will be available in the United States after May 11.
The approval is supported by data from two Phase 3 trials (Trial 052 (NCT05630755) and Trial 051 (NCT05631093)) evaluating virologically suppressed adults, where IDVYNSO demonstrated non-inferior efficacy compared with standard oral antiretroviral regimens at Week 48.
In both studies, the proportion of patients with HIV-1 RNA ≥50 copies/mL remained low, while viral suppression rates were comparable or slightly higher in patients switched to IDVYNSO versus those continuing baseline therapy.
Safety outcomes were also broadly similar across treatment groups, with low rates of discontinuation due to adverse events and commonly reported side effects including diarrhea, dizziness, fatigue, abdominal distention, and headache. Weight changes were minimal.
According to Eliav Barr senior vice president and chief medical officer, Merck Research Laboratories, the regimen represents a new option as the only two-drug, non-integrase inhibitor, tenofovir-free oral therapy, expanding treatment choices for adults living with HIV whose needs evolve over time.
Carl Baloney Jr. president and chief executive officer of AIDS United, emphasized that longer life expectancy among people with HIV requires treatment strategies that also address aging-related comorbidities and medication burden.
Amy Colson director of research at Community Resource Initiative, Boston, Massachusetts added that the regimen’s non-inferior efficacy compared with standard therapies supports its use as a potential switch option for virologically suppressed patients.
IDVYNSO is intended as a complete regimen and should not be co-administered with other antiretroviral therapies. It is contraindicated with strong CYP3A enzyme inducers and certain antiretrovirals such as lamivudine and emtricitabine due to the risk of reduced effectiveness.
Serious adverse reactions, including severe skin conditions such as Stevens-Johnson syndrome, toxic epidermal necrolysis, and Drug Rash with Eosinophilia and Systemic Symptoms, have been reported.
The dual mechanism of islatravir, combined with doravirine’s established efficacy profile, provides an alternative treatment approach within the evolving HIV therapy landscape. An ongoing study, MK-8591A-053, is further evaluating the doravirine/islatravir regimen to generate additional data on its long-term safety and use across broader patient populations.
Reference
FDA Approves Merck’s Once-Daily IDVYNSO™ (doravirine/islatravir) – Merck.com
About the Writer
Nikita Jha, BPharm a pharmacy graduate specializing in medical writing, with a strong ability to interpret complex medical and regulatory information and translate it into clear, accurate, and evidence-based healthcare content. Known for her attention to detail and precision, she focuses on delivering high-quality scientific communication that supports drug safety and informed decision-making.