A majority of people living with HIV (PLWH) in Spain successfully maintained viral suppression after switching to long-acting injectable cabotegravir plus rilpivirine, according to a study published October 21, 2026, in Open Forum Infectious Diseases. The research, which tracked 3,349 adults across 53 centers, found that 95.5% of participants remained virally suppressed at their closest assessment after a median follow-up of 25.1 months.
The study, led by Dr. Luis Buzón of the Hospital Universitario de Burgos, evaluated individuals who transitioned from standard daily oral antiretroviral therapy to the injectable regimen between June 2023 and December 2024. Among the cohort, 89.0% of participants remained on the injectable treatment throughout the study period.
Study Participants Experience Low Rates of Virologic Failure
Protocol-defined virologic failure occurred in 28 participants, representing 0.8% of the study population. Data showed that 71.4% of these failures occurred within the first 12 months following the switch to the injectable therapy. Resistance to integrase inhibitors or nonnucleoside reverse transcriptase inhibitors emerged in 19 of those 28 cases.
Discontinuation of the therapy was reported by 370 participants, or 11.0% of the cohort. The primary drivers for stopping the injections were nonvirologic factors, which accounted for 248 cases. Adverse events were less common, with 79 participants citing injection-site reactions and 54 reporting systemic adverse events. Adherence to the injection schedule remained high, with 99.3% of evaluable participants maintaining 90% or higher compliance with their scheduled appointments.
Evidence from the OPERA Cohort
Broader clinical insights reinforce these findings through the five-year OPERA study, which analyzed 6,955 individuals in the United States who switched to cabotegravir and rilpivirine between January 2021 and December 2025, with follow-up through February 2026. This cohort—which included a diverse demographic of 43% Black and 32% Hispanic/Latine participants—showed that 94% of individuals maintained viral loads below 50 copies/mL at their last measurement.
Dr. Ricky K. Hsu, the lead author of the OPERA analysis and National Medical Director at the AIDS Healthcare Foundation, noted that the data strengthen the evidence base for long-acting therapy. “The data offer vital, highly encouraging insights around treatment persistence with the long-acting therapy, showing that overall discontinuations were low and not commonly attributed to a lack of therapeutic efficacy or injection site pain,” Dr. Hsu said.
Clinical Considerations for Maintenance Therapy
The authors of the Spanish cohort study emphasized that their findings support the use of cabotegravir and rilpivirine as a durable maintenance option for carefully selected patients. They highlighted the necessity of early monitoring and the prompt confirmation of any viral rebound to facilitate resistance testing and individualized rescue therapy.
The study in Open Forum Infectious Diseases was observational and did not include a control group. Researchers noted that the study excluded individuals who were pregnant, breastfeeding, or hepatitis B surface antigen-positive. Additionally, the limited number of virologic failures constrained the team’s ability to identify specific risk factors for treatment non-response.
Common Questions Regarding Injectable HIV Therapy
Who is considered an appropriate candidate for this injectable regimen?
The study focused on adults who were already virally suppressed—defined as having an HIV-1 RNA load of less than 50 copies/mL—prior to switching from their daily oral antiretroviral therapy.
What happens if a patient misses an injection window?
The study measured adherence by comparing scheduled and administered injection dates within a ± 7-day window. Results indicated that high adherence levels were maintained, with 99.3% of participants hitting at least 90% of their required injections.
How does the Spanish cohort data compare to US findings?
While the Spanish study focused on a 25-month follow-up period, the OPERA study in the U.S. provided a five-year perspective, confirming that high rates of viral suppression remain consistent across diverse, real-world populations.
Related reading