Gilead Sciences and Merck have announced that the primary efficacy endpoint at week 48 was met in both the phase 3 ISLEND-1 and ISLEND-2 trials with the investigational oral once-weekly single-tablet HIV treatment regimen of islatravir/lenacapavir. The ISLEND trials are evaluating the efficacy and safety of islatravir 2 mg/lenacapavir 300 mg (ISL/LEN) in people with HIV who are virologically suppressed and switched from BIKTARVY (bictegravir 50 mg/emtricitabine 200 mg/tenofovir alafenamide 25 mg tablets, B/F/TAF) (ISLEND-1) or standard of care antiretroviral regimens (ISLEND-2).

The safety profile of ISL/LEN was generally comparable to the comparator regimens studied in the ISLEND trials, and no new safety concerns were identified. Gilead and Merck plan to file the phase 3 data from the ISLEND trials with regulatory authorities globally and submit the detailed findings for presentation at a future scientific congress.

Jasred Baeten, MD, PhD, Senior Vice President (SVP), Clinical Development, Virology Therapeutic Area Head, Gilead Sciences, said, “Long-acting oral therapies represent a new wave of transformational innovation in HIV drug development, with the potential to reshape the landscape of care. Innovative oral HIV treatment options that allow for less frequent dosing may make a meaningful difference in the lives of people living with the virus, potentially offering more flexibility and discretion.”

The primary efficacy endpoint of ISLEND-1 and ISLEND-2 was the percentage of participants with HIV-1 RNA levels ≥ 50 copies/mL at week 48, defined by the FDA snapshot algorithm. In the double-blind ISLEND-1 trial, the once-weekly, single-tablet regimen of ISL/LEN was found to be statistically non-inferior to BIKTARVY.

In the open-label ISLEND-2 trial, ISL/LEN was found to be statistically non-inferior to standard of care daily oral antiretroviral therapy regimens. The safety profile of ISL/LEN was generally comparable to BIKTARVY in ISLEND-1 and to standard of care antiretroviral regimens in ISLEND-2.

Dr. Eliav Barr, Senior Vice President, Head of Global Clinical Development and Chief Medical Officer (CMO), Merck Research Laboratories, said, “These results underscore the shared focus and commitment that we and our collaborators at Gilead have on continuing research to help people living with HIV. By advancing this investigational novel once-weekly oral regimen of islatravir and lenacapavir, we aim to bring forward a new long-acting oral option that, if approved, would represent the first of its kind with less frequent dosing and further expand options for people living with HIV.”

The combination of islatravir and lenacapavir targets multiple stages of HIV-1 replication, potentially offering people with HIV who are virologically suppressed, a novel, long-acting oral single-tablet regimen. The potency and pharmacokinetic profiles of islatravir and lenacapavir enable long-acting dosing as a once-weekly tablet for HIV treatment, if approved.

Islatravir and lenacapavir in combination are investigational and not approved for use.

There is currently no cure for HIV or AIDS.