HIV Drug Combo Shows Lasting Viral Suppression

A recent 96-week Phase III study has demonstrated that Merck's fixed-dose combination of doravirine and islatravir (DOR/ISL) effectively supports durable viral suppression in adults with HIV who were previously on oral antiretroviral therapy. The results were presented at the 33rd Conference on Retroviruses and Opportunistic Infections (CROI 2026) in Denver, Colorado. This investigational regimen, a once-daily, two-drug single-tablet treatment, is positioned as an integrase-sparing option.

The market is increasingly favoring two-drug regimens over older three- or four-drug options to simplify treatment and minimize toxicity. DOR/ISL is currently in the pre-registration stage in the US, with an anticipated launch in 2026 if approved. Key opinion leaders suggest that demonstrating reduced side effects, particularly concerning weight gain and central nervous system tolerability, will be crucial for its adoption.

Safety outcomes from the study remained consistent with earlier findings throughout the 96 weeks. Adverse event rates were comparable across treatment periods, and no discontinuations were linked to immune cell count declines. While overall weight changes were modest, larger increases were noted in participants switching from regimens containing efavirenz and/or tenofovir disoproxil fumarate, aligning with previous observations of weight changes after discontinuing therapies that suppress weight.