Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced that the U.S. Food and Drug Administration (FDA) has approved Pifeltro (doravirine, 100 mg), a new non-nucleoside reverse transcriptase inhibitor (NNRTI) to be administered in combination with other antiretroviral medicines. Pifeltro is indicated for the treatment of HIV-1 infection in adult patients with no prior antiretroviral treatment experience, and is administered orally once daily with or without food. Pifeltro does not cure HIV-1 infection or AIDS.
The FDA also approved Delstrigo, a once-daily fixed-dose combination tablet of doravirine (100 mg), lamivudine (3TC, 300 mg) and tenofovir disoproxil fumarate (TDF, 300 mg).
Pifeltro is contraindicated when co-administered with drugs that are strong cytochrome P450 (CYP)3A enzyme inducers as significant decreases in doravirine plasma concentrations may occur, which may decrease the effectiveness of Pifeltro.
Data Supporting the Approval of Pifeltro (doravirine)
The FDA approvals of Delstrigo, the once-daily fixed-dose combination tablet as a complete regimen, and Pifeltro, a new NNRTI, are based on findings from the pivotal, randomized, multicenter, double-blind, active controlled Phase 3 trials, DRIVE-AHEAD and DRIVE-FORWARD, evaluating the efficacy and safety of Delstrigo and Pifeltro, respectively, in participants infected with HIV-1 with no antiretroviral treatment history.
The DRIVE-FORWARD Clinical Trial
In DRIVE-FORWARD, 766 participants with no antiretroviral treatment history were randomized and received at least one dose of either Pifeltro once daily or darunavir 800 mg + ritonavir 100 mg (DRV+r) once daily, each in combination with emtricitabine (FTC)/TDF or abacavir (ABC)/3TC selected by the investigator. Pifeltro demonstrated sustained viral suppression through 48 weeks, meeting its primary endpoint of non-inferior efficacy compared to DRV+r, each in combination with FTC/TDF or ABC/3TC (84% in the Pifeltro group achieved viral suppression of HIV-1 RNA <50 copies/mL vs. 80% in the DRV+r group; treatment difference: 3.9%, [95% CI:] -1.6%, 9.4%). Of the 20 percent of study participants with a high viral load at baseline (HIV-1 RNA >100,000 copies/mL), 77 percent in the Pifeltro group and 74 percent in the DRV+r group achieved HIV-1 RNA <50 copies/mL at Week 48.