Merck, known as MSD outside the United States and Canada, announced the presentation of additional data from its Phase 3 studies evaluating the investigational, once-daily, oral, two-drug regimen of doravirine/islatravir [DOR/ISL (100 mg/0.25 mg)] in adults with HIV-1 infection who were virologically suppressed. The data, presented at the 20th European AIDS Conference in Paris, demonstrate that treatment with DOR/ISL resulted in minimal changes in weight and body composition and no clinically meaningful effects on fasting lipids or insulin resistance across clinical trials.

These findings follow positive Phase 3 results presented earlier this year at CROI 2025.

“Weight and body composition are central concerns for many people living with HIV, who may also face obesity and other metabolic challenges,” said Dr. Chloe Orkin, Dean for Healthcare Transformation at Queen Mary University of London. “The Week 48 results from the DOR/ISL Phase 3 trial are encouraging, showing minimal and comparable changes in weight and body composition after switching to DOR/ISL.”

“Comorbid conditions play a critical role in the overall management of HIV,” said Dr. Eliav Barr, Senior Vice President and Chief Medical Officer, Merck Research Laboratories. “We are pleased that these data show switching to DOR/ISL had minimal impact on weight and body composition and no clinically meaningful effect on fasting lipids in adults with virologically suppressed HIV-1 infection.”

Earlier this year, the U.S. Food and Drug Administration (FDA) accepted Merck’s New Drug Application (NDA) for DOR/ISL and set a target action date of April 28, 2026, under the Prescription Drug User Fee Act (PDUFA).