Predictors of Post-switch Viremia in People With HIV on Injectable Cabotegravir/Rilpivirine

Background: Predictors of virologic failure in those receiving long-acting injectable (LAI) cabotegravir/rilpivirine (CAB/RPV) have been evaluated; however, factors associated with low-level viremia, including blips and persistent low-level viremia (pLLV), are not well-described.Methods: A retrospective cohort study was performed using data from April 2021 through December 2022. Inclusion criteria included treatment with CAB/RPV for at least 3 months, availability of pre- and postswitch HIV RNA values, HIV RNA value of <200 copies/mL (cpm) at the time of switch to CAB/RPV, and at least 1 postswitch HIV RNA collected >21 days after the start of CAB/RPV. Outcomes included incidence of HIV RNA >= 20, >= 50, and >= 200 cpm after switch and factors associated with detectable HIV RNA after switch.Results: The median duration of follow-up among 144 participants was 287 days. After switching to CAB/RPV, occurrences of at least 1 HIV RNA >= 20, >= 50, and >= 200 cpm after switch were 34.7%, 15.3%, and 2.8%, respectively. Those with pLLV before switch were significantly more likely to have detectable HIV RNA after switch [hazard ratio 24.39 (8.71-68.34)], and 44.4% of those with pLLV before switch continued with pLLV after switch to LAI CAB/RPV. Body mass index, late injection, and monthly versus every two-month dosing were not associated with detectable viremia after switch.Conclusions: Despite virologic suppression at the time of switch and the perceived adherence benefits, participants still experienced blips or pLLV after switch to LAI CAB/RPV. Having detectable HIV RNA on oral therapy before switch was associated with detectable HIV RNA after switching.