Merck expands HIV portfolio with FDA approval of Idvynso single-tablet regimen

USA—The U.S. Food and Drug Administration (FDA) has approved Merck & Co.’s once-daily HIV treatment, Idvynso (doravirine/islatravir), giving adults living with HIV-1 a new simplified oral treatment option.

The newly approved single-tablet regimen is designed for adults who are already virologically suppressed, with HIV-1 RNA levels below 50 copies per milliliter, and is intended to replace their current antiretroviral therapy regimen.

The approval marks another milestone in Merck’s HIV treatment portfolio as the company continues to expand its antiviral pipeline.

The tablet combines 100 mg of doravirine and 0.25 mg of islatravir in a once-daily formulation.

It is approved for adults who have remained stable on treatment, have no history of virologic failure, and show no known resistance-associated substitutions linked to doravirine.

Merck noted that Idvynso will become available through U.S. pharmacies beginning May 11, providing clinicians with a fresh alternative for long-term HIV management.

Unlike many currently available oral therapies, the treatment is both tenofovir-free and non-integrase strand transfer inhibitor-based, offering a different mechanism for patients who may benefit from switching regimens.

Clinical trial data supports approval

The FDA based its decision on data from two Phase 3 randomized, active-controlled, non-inferiority studies that evaluated the regimen’s ability to maintain viral suppression.

In Trial 052, a double-blind study involving 513 participants, researchers compared patients who switched to Idvynso with those who remained on Biktarvy.

At 48 weeks, only 1% of participants in both groups recorded viral loads of 50 copies/mL or higher, confirming non-inferior efficacy.

Similarly, Trial 051, an open-label study involving 551 participants, compared patients who switched to Idvynso with those who stayed on their existing oral antiretroviral therapy.

Results showed that 1% of those receiving Idvynso had viral loads above the threshold after 48 weeks, compared with 5% among those who remained on standard treatment.

Strategic importance for Merck’s HIV pipeline

Merck described the approval as a major advancement for its HIV research strategy.

Dr. Eliav Barr, senior vice president and chief medical officer at Merck Research Laboratories, said the approval broadens treatment diversity and addresses the changing health needs of adults living longer with HIV.

The company is also advancing broader islatravir-based programs, including once-weekly investigational regimens currently in clinical development.

Industry analysts say that while Idvynso’s immediate commercial impact may be modest, the approval strengthens Merck’s long-term position in the HIV treatment market as demand grows for simplified, lower-burden therapies.