Phase 2 Results: Islatravir and Lenacapavir Weekly Regimen Sustains HIV Suppression

A recent Phase 2 clinical trial has shown promising results for a new combination of investigational drugs islatravir and lenacapavir, which could potentially offer a long-acting oral treatment for HIV. The study, conducted by Gilead Sciences and Merck & Co., demonstrated that the novel combination maintained a high rate of viral suppression at 24 weeks, with 94.2% of participants showing HIV-1 RNA levels below 50 copies/mL. This finding is significant as it indicates the potential for a weekly oral HIV treatment, which could address adherence challenges and reduce the stigma associated with daily medication.

The study involved 104 virologically suppressed adults who were randomly assigned to receive either the islatravir and lenacapavir combination once a week or to continue with their daily Biktarvy regimen. Biktarvy is a single-tablet treatment containing bictegravir, emtricitabine, and tenofovir alafenamide. The results showed that one participant in the experimental group had a viral load above the threshold at Week 24, but later achieved suppression at Week 30. Importantly, no participants in the Biktarvy group had a viral load above 50 copies/mL at Week 24.

The safety profile of the islatravir and lenacapavir combination was also evaluated, with Grade 1 and 2 treatment-related adverse events including dry mouth and nausea, each affecting 3.8% of participants. No serious adverse events related to the study drugs were reported, and two participants discontinued treatment due to non-drug-related adverse events.

The study's findings were presented at the 31st Conference on Retroviruses and Opportunistic Infections (CROI), highlighting the potential of this combination as a less frequent dosing option for HIV treatment. Jared Baeten, Vice President of HIV Clinical Development at Gilead Sciences, emphasized the importance of developing personalized treatment options to maximize long-term outcomes for people living with HIV.

The Phase 2 study will continue with an open-label design through Week 48, with longer-term data expected to be presented at a future scientific conference. Islatravir and lenacapavir are currently investigational and not approved for use anywhere globally. Lenacapavir, marketed as Sunlenca, is approved in select regions for the treatment of multi-drug resistant HIV in combination with other antiretrovirals.

The development of this potential once-weekly oral therapy reflects ongoing efforts to evolve HIV treatment strategies and provide additional options for individuals living with HIV. Both Gilead and Merck are committed to advancing this research and potentially transforming the HIV treatment landscape.

It is important to note that while islatravir and lenacapavir show promise, they are not yet approved for use, and further research is needed to establish their safety and efficacy. The ongoing Phase 2 study will provide valuable insights into the long-term effects and potential benefits of this novel combination treatment for HIV.