Highlight
- Monthly long-acting injectable cabotegravir plus rilpivirine (LA-ART) demonstrated a 22.8% regimen failure rate compared to 41.2% for standard oral therapy at 48 weeks.
- The LATITUDE trial was stopped early due to the clear superiority of the injectable regimen in a population previously considered ‘difficult to treat’ due to adherence challenges.
- The study highlights the potential for long-acting therapies to bridge the health equity gap for patients facing socioeconomic or structural barriers to daily pill-taking.
Background: The Persistent Challenge of ART Adherence
For decades, the cornerstone of HIV management has been daily oral antiretroviral therapy (ART). While modern oral regimens are highly effective and well-tolerated, their success is entirely dependent on strict adherence. For many individuals living with HIV, maintaining a daily pill burden is complicated by structural barriers, including housing instability, substance use disorders, mental health challenges, and the persistent stigma associated with the disease. Suboptimal adherence leads to virologic failure, the development of drug resistance, and increased risk of transmission.
Long-acting (LA) injectable regimens, such as the combination of cabotegravir and rilpivirine, offered a theoretical solution by removing the need for daily dosing. However, initial landmark trials (such as FLAIR and ATLAS) primarily enrolled participants who were already virologically suppressed and demonstrated high adherence to oral regimens. Consequently, clinical guidelines and insurance payers have historically been hesitant to recommend LA-ART for the very population that might benefit most: those with a history of poor adherence and detectable viral loads.
Study Design: The LATITUDE Trial (ACTG A5359)
The Long-Acting Therapy to Improve Treatment Success in Daily Life (LATITUDE) trial was specifically designed to address this evidence gap. This phase 3, open-label, randomized controlled trial targeted persons with HIV who had a history of inadequate adherence, defined as persistent HIV-1 RNA levels >200 copies/mL or a history of being lost to follow-up.
Step 1: Stabilization and Support
The trial utilized a unique two-step structure. In Step 1, 453 participants received intensive adherence support, including conditional economic incentives and standard oral ART, for up to 24 weeks. The goal was to achieve virologic suppression (HIV-1 RNA ≤200 copies/mL) before transitioning to the injectable phase.
Step 2: Randomization
Participants who successfully achieved suppression in Step 1 (n=306) were randomized in a 1:1 ratio. The intervention group received monthly intramuscular injections of cabotegravir (600 mg) and rilpivirine (900 mg), with or without a short oral lead-in period. The control group continued standard-of-care oral ART. The primary endpoint was regimen failure, a composite of confirmed virologic failure or treatment discontinuation.
Key Findings: Superiority and Early Termination
The trial’s Data and Safety Monitoring Board (DSMB) recommended stopping the randomization phase early after a planned interim analysis at a median follow-up of 48 weeks. The evidence of superiority for the long-acting injectable regimen was statistically and clinically significant.
Efficacy and Regimen Failure
The cumulative incidence of regimen failure by week 48 was 22.8% in the cabotegravir-rilpivirine group, compared to a staggering 41.2% in the standard oral care group. This represents an absolute difference of -18.4 percentage points (98.4% CI, -32.4 to -4.3; P = 0.002). This finding confirms that for patients who struggle with daily pills, the transition to a monthly injection provides a more robust safeguard against treatment interruption.
Safety and Resistance
Safety profiles were comparable between the two groups. Adverse events occurred in 43.5% of the injectable group and 42.4% of the oral group. Importantly, the development of resistance-associated mutations was rare and balanced, occurring in only two participants in each group. This addresses a major clinical concern that missed injection windows in non-adherent patients might lead to a ‘pharmacokinetic tail’ favoring the rapid development of multi-drug resistance.
Expert Commentary: Shifting the Paradigm
The results of the LATITUDE trial represent a paradigm shift in HIV medicine. For years, clinicians were taught that ‘stability’ on oral ART was a prerequisite for long-acting therapy. LATITUDE suggests the opposite: LA-ART may be the tool used to *create* stability in those who cannot achieve it with pills.
However, implementation remains a challenge. The trial utilized conditional economic incentives and intensive case management during the induction phase (Step 1). Replicating these support structures in real-world clinical settings—particularly in resource-limited or high-volume clinics—will require significant policy shifts and increased funding for HIV care coordination. Furthermore, the 22.8% failure rate in the injectable arm, while superior to oral ART, indicates that long-acting therapy is not a panacea; patients still require a reliable clinical infrastructure to ensure they receive their monthly injections.
Conclusion
The LATITUDE trial provides high-quality, randomized evidence that monthly injections of cabotegravir and rilpivirine are superior to standard oral ART for individuals with HIV who face adherence challenges. By demonstrating that virologic suppression can be maintained in high-risk populations through long-acting formulations, this study paves the way for broader access to these therapies. It underscores the necessity of moving beyond ‘one-size-fits-all’ treatment models to address the complex social and behavioral realities of patients living with HIV.
Funding and ClinicalTrials.gov
The study was funded by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. ClinicalTrials.gov number: NCT03635788.
References
1. Rana AI, et al. Cabotegravir plus Rilpivirine for Persons with HIV and Adherence Challenges. N Engl J Med. 2026 Feb 18. doi: 10.1056/NEJMoa2508228.
2. Landovitz RJ, et al. Cabotegravir for HIV Prevention in Cisgender Men and Transgender Women. N Engl J Med. 2021;385(7):595-608.
3. Orkin C, et al. Long-Acting Cabotegravir and Rilpivirine after Oral Induction: The FLAIR Trial. N Engl J Med. 2020;382(12):1124-1135.
