Gilead, Merck announce from Phase 2 islatravir/lenacapavir combo study

Gilead Sciences (GILD) and Merck (MRK) announced new results from a Phase 2 clinical study evaluating the investigational combination of islatravir, an investigational nucleoside reverse transcriptase translocation inhibitor, and lenacapavir, a first-in-class HIV-1 capsid inhibitor. These late-breaking data were presented during an oral session at IDWeek 2024, taking place in Los Angeles, and virtually, from October 16-19. At 48 weeks, the novel investigational combination maintained a high rate of viral suppression in virologically suppressed adults, a secondary endpoint of the study. Zero participants had a viral load of greater than or equal to50 copies/mL at Week 48. Week 24 results, including the study’s primary endpoint, were previously presented at the 31st Conference on Retroviruses and Opportunistic Infections. In this open-label, active-controlled study, virologically suppressed adults on Biktarvy were randomly allocated in a 1:1 ratio to receive either oral islatravir 2 mg and lenacapavir 300 mg once a week or to continue daily oral Biktarvy. The median age of participants was 40 years. Eighteen percent of participants were assigned female at birth, 50% were non-white, and 29% were Latine. The proportion of individuals with HIV-1 RNA less than50 c/mL at Week 48 by FDA snapshot algorithm, showed that participants who switched to treatment with once-weekly islatravir and lenacapavir or continued Biktarvy maintained comparable high rates of HIV suppression at Week 48. No participants treated with either ISL + LEN or Biktarvy had a viral load of greater than or equal to 50 copies/mL at Week 48. No grade 3 or 4 TRAEs related to the study drug were reported in either treatment group. Two participants discontinued ISL + LEN due to adverse events unrelated to the drug. At Week 48 no significant differences were seen between treatment groups in mean change from baseline in CD4+ T-cell counts or absolute lymphocyte counts. No participants discontinued due to a decrease in CD4+ T-cell or lymphocyte counts. Along with these most recent study results, the potent antiviral activities, and pharmacokinetic profiles of islatravir and lenacapavir support their continued development as an investigational once-weekly oral combination regimen for use in people with HIV who are virologically suppressed. This investigational combination of weekly oral ISL 2 mg + LEN 300 mg is being further evaluated as a fixed-dose combination regimen in two Phase 3 studies in virologically suppressed people with HIV.