HIV Treatment Pipeline Advances with Extended-Release Formulations from Weekly to Annual Dosing
Key Insights
The HIV (search) treatment pipeline for 2025 features innovative dual-drug combinations with extended dosing intervals ranging from weekly oral tablets to six-monthly injections, representing a significant shift toward treatment simplification.
Nine studies presented at Glasgow 2024 demonstrated promising results for nucleoside-sparing combinations using novel drug classes including capsid (search) inhibitors, with companies like Gilead, MSD, and ViiV Healthcare leading development efforts.
Phase 2/3 trials are advancing multiple long-acting formulations, including lenacapavir-based combinations and ultra-long-acting versions of existing drugs, though challenges remain regarding cost-effectiveness against upcoming generic dolutegravir.
The HIV (search) treatment landscape is undergoing a dramatic transformation as pharmaceutical companies advance an unprecedented pipeline of extended-release antiretroviral combinations, with dosing intervals extending from once-weekly oral tablets to annual injections. Data presented at the Glasgow 2024 conference revealed nine studies evaluating novel dual-drug combinations that promise to revolutionize HIV care through dramatically simplified dosing schedules.
José Arribas from La Paz Hospital in Madrid presented comprehensive pipeline data showing that the exceptional potency of new compounds and improved resistance profiles enable effective two-drug combinations across multiple dosing frequencies. These nucleoside-sparing regimens span from daily oral tablets to six-monthly injections, though they notably lack hepatitis B (search) virus coverage.
Weekly Oral Combinations Lead Near-Term Pipeline
The most advanced extended-release formulations involve once-weekly oral dosing, with three distinct combinations currently in phase 2/3 development. Islatravir combined with lenacapavir represents the furthest progressed weekly option, with early phase 2 switch study results demonstrating comparable viral efficacy to daily bictegravir/emtricitabine/tenofovir alafenamide at 48 weeks.
Two phase 3 switch studies, ISLEND-1 and ISLEND-2, are already evaluating this 2 mg islatravir plus 300 mg lenacapavir combination against standard daily regimens. However, critical pharmacokinetic data regarding drug levels at day 14 following a missed weekly dose remain unavailable, raising questions about the robustness of viral suppression during dosing interruptions.
MSD is simultaneously developing islatravir with ulonivirine, an NNRTI similar to doravirine, in a phase 2b dose-finding study. Additionally, Gilead is advancing GS-1720 and GS-4182, representing an integrase (search) inhibitor and capsid (search) inhibitor combination with half-lives of approximately 9 and 11 days, respectively.
Monthly and Quarterly Injectable Options Emerge
Extended-release injectable formulations are progressing through early-phase development, with ViiV Healthcare's VH4011499 (VH-499) capsid (search) inhibitor designed for two-monthly self-administered injections currently in phase 2a monotherapy studies.
Independent investigators have explored off-label combinations of existing long-acting drugs, with notable success reported using cabotegravir-LA plus six-monthly lenacapavir injections. A French study demonstrated maintained viral suppression in eight highly treatment-experienced participants with rilpivirine resistance and adherence challenges, including four individuals with current CD4 counts below 200 cells/mm³.
Ultra-long-acting formulations of cabotegravir plus rilpivirine are being developed for four-monthly dosing, with the subcutaneous formulation showing a six-fold longer half-life compared to current two-monthly intramuscular injections.
Six-Monthly and Annual Dosing on the Horizon
The most ambitious pipeline developments target six-monthly dosing intervals using both small molecules and broadly neutralizing antibodies (bNAbs). ViiV Healthcare is developing VH-184, a third-generation integrase (search) inhibitor with distinct resistance profiles, and VH-310, a cabotegravir prodrug with extended pharmacokinetics.
Broadly neutralizing antibodies represent a novel therapeutic class, with N6LS (VH3810109) showing activity against 98% of viral isolates. Phase 1 BANNER study results demonstrated median antiviral activity of -1.7 log at day 11 monotherapy, with 81% of participants achieving minimum viral load response greater than 0.5 log copies/mL.
Gilead is advancing teropavimab and zinlirvimab, two bNAbs developed at Rockefeller University, in combination with lenacapavir. While approximately 90% of clade B viruses show susceptibility to at least one bNAb, baseline sensitivity prediction remains challenging and resistance can develop during monotherapy.
Daily Oral Innovations Continue
Despite the focus on extended-release formulations, daily oral combinations continue advancing through clinical development. The lenacapavir plus bictegravir combination showed statistically similar virologic responses to complex existing regimens in the ARTISTRY-1 switch study, with additional metabolic benefits including improved fasting lipids.
MSD announced non-inferiority results for doravirine plus islatravir (100 mg/0.25 mg daily) in phase 3 studies, though superiority was not achieved. These results are expected to be presented at CROI 2025.
Economic Challenges Loom
The approaching patent expiration of dolutegravir by 2029 presents significant economic challenges for premium-priced pipeline combinations. Generic dolutegravir-based regimens could potentially cost as little as $50 annually in high-income settings, requiring new combinations to demonstrate clear superiority or population-based benefits to justify higher pricing.
José Arribas argued that clinical superiority in specific populations, including pregnancy, aging, and renal/hepatic impairment, along with reduced dosing frequency benefits, could support premium pricing despite generic competition. The broader healthcare cost reductions from simplified dosing schedules may offset higher drug acquisition costs.
The HIV (search) treatment pipeline represents an unprecedented convergence of pharmaceutical innovation, with multiple companies advancing complementary approaches to treatment simplification. As these combinations progress through late-phase development, they promise to transform HIV care through dramatically reduced dosing frequencies while maintaining the high efficacy standards established by current daily regimens.