Outcomes in people with HIV who resume or switch to bictegravir/emtricitabine/tenofovir alafenamide following a treatment interruption.

Objective: Treatment adherence remains critical in maintaining HIV RNA suppression on antiretroviral therapy. High genetic barrier regimens constructed with three long half-life agents may prevent resistance emergence and can be potentially started or restarted after antiretroviral treatment interruption (TI).

Methods: Data from the TRIO US HIV cohort were used to identify adult people with HIV initiating a new ART regimen from January 2021 - November 2023 and describe prevalence of TIs (defined as ≥90 days without dispensed ART). Virologic outcomes were assessed among those restarting or switching to B/F/TAF after TI.

Results: Of 2710 people with HIV, 765 (28%) experienced TI. Compared to individuals without TIs, those with TIs had higher proportion of females (24% vs 19%), black race (50% vs 35%), substance use (14% vs 9%), CD4 <200 cells/mm3 (15% vs 8%) and lower proportion with commercial insurance (48% vs 62%) or virologic suppression at initiation (76% vs 85%). Among 379 who restarted or switched to B/F/TAF following TI, 245 (65%) were suppressed at restart; 137 (56%) had ≥1 viral load (VL) after TI, of whom 129 (94%) maintained suppression. Of 87 with unknown viral status at restart, 46 (53%) had ≥1 VL during follow-up, of whom 44 (96%) achieved suppression. Among 47 viremic at restart, 27 (57%) had ≥1 VL after TI. Of them, 70% were suppressed during follow-up. No integrase inhibitor resistance emergence was observed.

Conclusions: High levels of suppression following TI may suggest B/F/TAF regimen forgiveness making it an appropriate choice for treatment switch or restart.