Gilead & Merck’s Once-Weekly HIV Treatment Shows Promising Results in Phase 2 Trial
Gilead and Merck's Phase 2 study shows a 94.2% viral suppression rate with islatravir and lenacapavir.
Breaking News
Oct 21, 2024
Simantini Singh Deo

Gilead Sciences, Inc. and Merck, known as MSD outside the U.S. and Canada, announced new findings from a Phase 2 study on an investigational combination of islatravir, a nucleoside reverse transcriptase translocation inhibitor, and lenacapavir, an HIV-1 capsid inhibitor. These results were presented during IDWeek 2024, both in-person and virtually, from October 16-19 in Los Angeles.
At 48 weeks, the investigational regimen showed a 94.2% rate of viral suppression (HIV-1 RNA <50 copies/mL) among virologically suppressed adults, with no participants experiencing viral loads of ≥50 copies/mL. Previously, Week 24 results were presented at the 31st Conference on Retroviruses and Opportunistic Infections (CROI).
Jared Baeten, MD, PhD, Senior Vice President, Virology Therapeutic Area Head, Gilead Sciences, said in a statement, “The future of HIV treatment is person-centered, with long-acting options tailored to help meet the needs and preferences of people affected by HIV. There is no ‘one size fits all’ approach. The complexities of HIV care require putting people first in the development of biomedical innovations as we keep striving to offer options for all those living with HIV. These data presented at IDWeek demonstrate our commitment to continuous scientific discovery aimed at further transforming the HIV treatment landscape.”
The open-label, active-controlled study (NCT05052996) involved 104 virologically suppressed adults who were randomly assigned to either receive once-weekly oral islatravir (2 mg) and lenacapavir (300 mg) (n=52) or continue with daily Biktarvy® (n=52). The study showed comparable high rates of HIV suppression at Week 48 between the two groups (94.2% for the ISL + LEN group vs. 92.3% for the Biktarvy group), with no significant differences in CD4+ T-cell or lymphocyte counts.
Treatment-related adverse events (TRAEs) were reported by 19.2% of participants in the ISL + LEN group, with dry mouth and nausea being the most common. In comparison, 5.8% of those on Biktarvy experienced TRAEs. No serious adverse events linked to the study drugs were observed, and two participants discontinued ISL + LEN due to unrelated adverse events.
Dr. Elizabeth Rhee, Vice President, Global Clinical Development Merck Research Laboratories, mentioned, “Daily single-tablet regimens have helped to transform HIV care but can be challenging for some people to maintain. Novel HIV treatment options that allow for less frequent oral dosing have the potential to help support adherence and address stigma faced by some individuals taking daily oral therapy. We are pleased to see these encouraging 48-week data for this once-weekly oral combination regimen and advance to phase 3 clinical trials in collaboration with Gilead.”
These promising results, along with the antiviral and pharmacokinetic profiles of islatravir and lenacapavir, support the continued development of this once-weekly oral combination for people with HIV who are virologically suppressed. The combination is now being further evaluated in two Phase 3 studies. Islatravir and lenacapavir remain under investigation and have not yet been approved globally. Their safety and efficacy as a treatment for HIV in virologically suppressed individuals have not been established. Lenacapavir is currently being studied in various clinical trials and may provide more flexible treatment options for people living with HIV.