Do we need to genotype before switching to long-acting injectable ART? New study offers insights

Among virally suppressed people who switch to long-acting injectable cabotegravir/rilpivirine, a successful treatment outcome is not dependent on the availability of genotypic resistance test results at the time of the switch, according to results from a recently published study. The findings should help ease anxieties among clinicians who are concerned about moving forward with an antiretroviral treatment (ART) switch without reliable resistance data in hand.

Highlighted Study Population and Methods

The authors performed an analysis of the RELATIVITY study data. RELATIVITY is a nationwide, multicenter, ambispective (retrospective and prospective) cohort assessing the effectiveness and safety of long-acting injectable (LAI) cabotegravir/rilpivirine (CAB/RPV) in virologically suppressed adults with HIV across 58 clinical centers in Spain.

This analysis assessed the real-world impact of genotypic testing for LAI CAB/RPV. Participants were partitioned into groups depending on whether genotypic resistance test data were available before switching: “genotype available” versus “no genotype available.”

This post-hoc analysis included 3,146 participants. Of these, 1,682 (~53.5%) did not have prior genotypic resistance data available. Median follow-up was 13.3 months (IQR 8.6–18.9) in the no-genotype group, 14.9 months (IQR 9.0–19.2) in the genotype group (P = 0.003).

Outcomes assessed included maintenance of viral suppression, rates of virologic failure, treatment discontinuation, immunological outcomes, adherence to injection schedule, and body mass index (BMI) changes.

Key Findings

• Both groups achieved high levels of sustained virological suppression (> 93%) through 23 months of follow-up, with no significant difference between the genotype and no-genotype groups.

• Permanent discontinuation rates were also similar: 6.1% in the no-genotype group versus 6.6% in the genotype group (P = 0.804).

• Virologic failure rates were very low and similar: 0.5% in the no-genotype group versus 0.8 % in the genotype group (P = 0.476).

• Among the 20 participants with virologic failure, 12 had genotype data; of those, eight achieved undetectable viral loads after resuming oral ART; among those without genotype data, four achieved undetectable viral loads.

• Adherence to injection schedules and BMI changes were comparable between groups.

Read an expert analysis from Benjamin Young, M.D., Ph.D. at TheBodyPro.