Merck Phase 3 HIV Findings Reinforce Safety in Weight and Lipids

Merck has reported new findings of its Phase 3 clinical trials testing its experimental once-daily, oral, two-drug combination of doravirine and islatravir [DOR/ISL (100mg/0.25mg) in adults with HIV-1 who already had reached virologic control.

Recent results, introduced at the 20th European AIDS Conference (EACS 2025) in Paris, indicate that there were only slight alterations in body composition and weight with no statistically significant clinical impact on fasting lipid levels or insulin resistance among the studies of DOR/ISL treatment.

These findings are an extension of the positive Phase 3 findings that were initially announced at the 2025 Conference on Retroviruses and Opportunistic Infections (CROI).

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"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.”