4 September 2018 - - The US Food and Drug Administration has approved two new HIV-1 medicines: Delstrigo, a once-daily fixed-dose combination tablet of doravirine (100 mg), lamivudine (3TC, 300 mg) and tenofovir disoproxil fumarate (TDF, 300 mg); and Pifeltro (doravirine, 100 mg), a new non-nucleoside reverse transcriptase inhibitor (NNRTI) to be administered in combination with other antiretroviral medicines, US-based pharmaceutical company Merck (NYSE: MRK) said.

Both Delstrigo and Pifeltro are indicated for the treatment of HIV-1 infection in adult patients with no prior antiretroviral treatment experience, and are administered orally once daily with or without food. Delstrigo contains a boxed warning regarding post-treatment acute exacerbation of hepatitis B infection.

Delstrigo and Pifeltro do not cure HIV-1 infection or AIDS.

Delstrigo and Pifeltro are contraindicated when co-administered with drugs that are strong cytochrome P450 3A enzyme inducers as significant decreases in doravirine plasma concentrations may occur, which may decrease the effectiveness of Delstrigo and Pifeltro. Delstrigo is contraindicated in patients with a previous hypersensitivity reaction to 3TC. For more information, see "Selected Safety Information" below.

Immune reconstitution syndrome can occur, including the occurrence of autoimmune disorders with variable time to onset, which may necessitate further evaluation and treatment.

Renal impairment, including cases of acute renal failure and Fanconi syndrome, have been reported with the use of TDF.

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.

In DRIVE-AHEAD, 728 participants with no antiretroviral treatment history were randomized and received at least one dose of either Delstrigo or efavirenz/emtricitabine/tenofovir disoproxil fumarate (EFV 600 mg/FTC 200 mg/TDF 300 mg) once daily.

Delstrigo demonstrated sustained viral suppression through 48 weeks, meeting its primary endpoint of non-inferior efficacy compared to EFV/FTC/TDF (84% in the DELSTRIGO group achieved viral suppression of HIV-1 RNA 100,000 copies/mL), 77% in the Delstrigo group and 72 % in the EFV/FTC/TDF group achieved HIV-1 RNA