REINItiation of Antiretroviral Therapy Using Oral bicTegravir, emtrIcitAbine and Tenofovir alafenamidE

This prospective, multicenter, open-label, single-arm, Phase 4, interventional study aims to evaluate rapid antiretroviral therapy (ART) restart with bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) in participants' routine clinical environments, facilitating data collection on treatment effectiveness and safety following same-day ART reinitiation amongst treatment-experienced people with HIV (PWH) who have had a treatment interruption of at least 12 weeks. This study will also characterize reasons for ART interruption and reinitiation. B/F/TAF, a three-drug combination of bictegravir (B; a second-generation HIV-1 integrase strand transfer inhibitor \[INSTI\]), and emtricitabine (F) and tenofovir alafenamide (TAF), both nucleoside reverse transcriptase inhibitors (NRTIs), is a recommended initial ART regimen for most people with HIV in the United States. B/F/TAF is an oral, once-daily fixed-dose combination (FDC) that provides a potent and well-tolerated regimen for the treatment of HIV-1 infection in people, including those with some pre-existing resistance and subpopulations that are underrepresented in clinical trials, including Black, Hispanic, and Latine PWH, PWH ≥65 years old, and pregnant adults. The rapid restart nature of this study involves the concurrent initiation of screening, baseline assessments, and administration of B/F/TAF on the same day. B/F/TAF is the only guideline-recommended single tablet regimen (STR) suitable for rapid restart, as it can be prescribed without prior knowledge of baseline laboratory parameters, including viral load, hepatitis B virus (HBV) status, or baseline genotypic resistance testing. This means the study treatment commences without baseline test results, provided the participant fulfills all eligibility criteria. There will be two Cohorts of participants within this study: Cohort 1 will include viremic participants (defined by HIV-1 RNA ≥50 copies/mL) at baseline and Cohort 2 will include virologically suppressed participants (defined by HIV-1 RNA \<50 copies/mL) at baseline. The study will aim to recruit 125 participants into Cohort 1 while simultaneously recruiting into Cohort 2 (it is assumed approx. 15-75 participants). The ratio of participants in Cohort 1 and Cohort 2 will be monitored during enrollment. Adherence and drop-out rates will be closely monitored throughout the study to mitigate the risk of insufficient sample sizes to power the planned analyses. Each participant's total study participation duration will be up to 48 weeks for data collection. Participants will be followed prospectively for 48 weeks in Cohort 1 and for 24 weeks in Cohort 2. Optional, semi-structured interviews will be conducted for a subset of participants in Cohorts 1 and 2 via teleconference at week 4 and week 24 after baseline screening and treatment reinitiation. While sample size will be informed by theoretical saturation, \~30 participants (15 per Cohort) is estimated to be sufficient. Achieving viral suppression (defined as HIV-1 RNA \<50 copies/mL) is the main goal of ART therapy for PWH who are viremic, and the primary objective of this study. It has been associated with improvements in CD4 cell counts, prevention of HIV drug resistance, AIDS- and non-AIDS-related events, and decreased transmission to sexual partners of PWH. Secondary outcomes include safety, resistance, persistence and adherence, and a range of patient-reported outcomes to understand patient experiences of ART.