By Fineline Cube 
Merck, Sharp & Dohme (MSD, NYSE: MRK) announced that the U.S. Food and Drug Administration (FDA) has accepted for review its New Drug Application (NDA) for the once-daily oral HIV-1 combination therapy doravirine/islatravir (DOR/ISL). The therapy is intended for virologically suppressed adults currently on antiretroviral therapy (ART), with the FDA expected to make its decision before April 28, 2026.
Clinical Trial Data Supporting NDA
The NDA is supported by findings at Week 48 of two pivotal Phase III clinical trials (MK-8591A-051 and MK-8591A-052). In the open-label trial MK-8591A-051, DOR/ISL demonstrated non-inferiority to baseline antiretroviral therapy (bART). In the double-blind trial MK-8591A-052, it showed non-inferiority to bictegravir/emtrictabine/tenofovir alafenamide (BIC/FTC/TAF [50mg/200mg/25mg]). Across both trials, the safety profile of DOR/ISL was generally comparable to the respective comparator regimens.
Islatravir’s Mechanism and Development
Islatravir, a nucleoside reverse transcriptase translocation inhibitor (NRTTI) with multimodal HIV-1 suppression, works by blocking reverse transcriptase translocation and inducing viral DNA structural changes. It is currently under evaluation in multiple early- and late-stage trials as part of once-daily and weekly HIV-1 regimens.-Fineline Info & Tech