Merck presents data from Phase 3 studies of doravirine/islatravir

Merck (MRK), known as MSD outside of the U.S. and Canada, announced the presentation of additional data from the Phase 3 studies of the investigational, once-daily, oral, two-drug regimen of doravirine/islatravir in adults with HIV-1 infection that was virologically suppressed on bictegravir/emtricitabine/tenofovir alafenamidei in trial MK-8591A-052 or antiretroviral in trial MK-8591A-051. These additional findings will be shared at the 20th European AIDS Conference being held in Paris and follow positive Phase 3 data presented at CROI 2025, which showed that the investigational two-drug regimen of DOR/ISL maintained viral suppression and demonstrated non-inferiority to the three-drug regimen BIC/FTC/TAF in MK-8591A-052 and baseline ART in MK-8591A-051, with no observed treatment-emergent resistance to DOR or ISL. In trial MK-8591A-052, adults living with virally suppressed HIV-1 infection who switched to DOR/ISL from BIC/FTC/TAF showed minimal changes in weight and body composition at Week 48. These changes were comparable to trial participants who continued BIC/FTC/TAF. In both trials, adults who switched to DOR/ISL from their current regimen saw no clinically meaningful changes in fasting lipids or in the homeostatic model assessment of insulin resistance. These changes were comparable to trial participants who continued on their respective prior antiretroviral therapy, BIC/FTC/TAF or bART. Participants who entered the trials on lipid-lowering therapy were excluded from the fasting lipids analysis. The percentage of participants who modified or initiated lipid-lowering therapy during the study was comparable across the treatment groups. In the double-blind trial MK-8591A-052, results for changes in weight and body composition showed that both the mean change and mean percent change in weight from baseline at Week 48 were minimal and similar in both treatment groups. Across both trials the pooled DOR/ISL group’s mean changes from baseline in fasting lipids, including total cholesterol, HDL, LDL and triglycerides were minimal, with no substantial differences from comparator groups. Mean changes in fasting insulin, glucose and HOMA-IR were minimal across groups. The proportion of participants with type 2 diabetes who modified their diabetic medication was less than5% across treatment groups. A comparable proportion of participants initiated lipid-lowering therapy across the two trials.