Key Takeaways:
Gilead Sciences Inc. and Merck & Co. said their investigational once-weekly oral HIV treatment met the primary efficacy endpoint at Week 48 in two Phase 3 trials, bringing the regimen a step closer to becoming the first long-acting oral therapy taken once weekly.
"Long-acting oral therapies represent a new wave of transformational innovation in HIV drug development, with the potential to reshape the landscape of care," Jared Baeten, senior vice president of clinical development and virology therapeutic area head at Gilead, said in a statement.
The ISLEND-1 and ISLEND-2 trials evaluated islatravir 2 milligrams/lenacapavir 300 milligrams (ISL/LEN) in people with HIV who were virologically suppressed. In the double-blind ISLEND-1 trial, the once-weekly single-tablet regimen was statistically non-inferior to Gilead's daily Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide). In the open-label ISLEND-2 trial, ISL/LEN was non-inferior to standard-of-care daily oral antiretroviral regimens. The safety profile was generally comparable across both studies, with no new safety concerns identified.
The combination pairs Merck's islatravir, a next-generation nucleoside analog that blocks HIV-1 replication through reverse transcriptase translocation inhibition, with Gilead's lenacapavir, a first-in-class capsid inhibitor that disrupts HIV at multiple stages of its lifecycle. The potency and pharmacokinetic profiles of both drugs enable once-weekly oral dosing, if approved.
"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," Eliav Barr, senior vice president and chief medical officer at Merck Research Laboratories, said.
The primary endpoint in both trials was the proportion of participants with HIV-1 RNA levels of 50 copies per milliliter or higher at Week 48, as defined by the US Food and Drug Administration snapshot algorithm. ISLEND-1 randomized participants 1-to-1 to receive ISL/LEN or continue Biktarvy, while ISLEND-2 compared ISL/LEN against standard-of-care regimens containing two or three antiretroviral medicines. Both studies will continue through Week 96.
Gilead and Merck plan to file the Phase 3 data with regulatory authorities globally and submit detailed findings for presentation at a future scientific congress. Islatravir and lenacapavir in combination remain investigational and are not yet approved for use. There is currently no cure for HIV or AIDS.
The positive readout de-risks a potential blockbuster product for both companies in the HIV treatment market, where daily oral pills dominate. Gilead shares fell 0.82 percent on the day, while Merck shares declined 1.05 percent. Investors will watch for regulatory filing timelines and potential PDUFA dates as the next catalysts.
This article is for informational purposes only and does not constitute investment advice.
