FDA approves Merck's once-daily Idvynso for virologically suppressed adults with HIV-1

The U.S. Food and Drug Administration has approved Merck's Idvynso (doravirine/islatravir), a once-daily, two-drug single tablet for adults with HIV-1 who are virologically suppressed, allowing clinicians to replace patients' existing antiretroviral regimen in those with HIV-1 RNA below 50 copies per mL.

The tablet combines 100 mg doravirine with 0.25 mg islatravir. According to the approval, it is indicated for adults on a stable antiretroviral regimen with no history of virologic treatment failure and no known substitutions associated with resistance to doravirine.

Idvynso is contraindicated for use with drugs that are strong cytochrome P450 (CYP)3A enzyme inducers and with lamivudine or emtricitabine. Regulators based the decision on two randomized, active-controlled, noninferiority trials. In the double-blind Trial 052, participants were randomly assigned either to remain on Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide; 171 individuals) or to switch to Idvynso (342 individuals).

At 48 weeks, 1% of participants in both groups had a viral load of at least 50 copies per mL. In the open-label Trial 051, participants were randomly assigned to stay on their oral antiretroviral therapy regimen (185 individuals) or to switch to Idvynso (366 individuals).

At week 48, 1% of those switched to Idvynso had a viral load of at least 50 copies per mL, compared with 5% who continued on their existing therapy.

"As the only two-drug, non-integrase strand transfer inhibitor, tenofovir-free regimen, Idvynso expands therapeutic diversity beyond the currently available oral treatment options," Eliav Barr, senior vice president and chief medical officer at Merck Research Laboratories, said in a statement.

"As the health needs of adults living with HIV change over time, Idvynso gives clinicians a new choice for HIV treatment." Merck said the data show that switching to Idvynso maintained viral suppression rates comparable to existing regimens at 48 weeks in the studied population.