B/F/TAF to DTG/3TC Switch Study

Overview

OBJECTIVE: To assess the efficacy and safety of switch to dolutegravir and lamivudine (DTG/3TC) single tablet regimen from bictegravir, emtricitabine and tenofovir alafenamide (B/F/TAF) in persons living with HIV aged 60 years old or more. METHODS: This is a phase 3b, multi-center, open-label, single-arm clinical trial over 96 weeks. The study will take place at two sites in Kenya: Kenyatta National Hospital (KNH) and Jaramogi Oginga Odinga Teaching and Referral Hospital (JOOTRH). Study visits will take place at screening, baseline, and weeks 4, 12, 24, 36, 48, 60, 72, 84, and 96 (with a 6-week extension as required for confirming HIV-1 RNA levels). A target of 240 participants from the ongoing B/F/TAF Elderly Switch Study will be enrolled. Eligible participants will be switched from B/F/TAF to DTG/3TC at enrollment and followed up for 96 weeks. The primary endpoint will be the proportion of participants with plasma HIV-1 RNA ≥ 50 copies/mL (Snapshot algorithm) at Week 48. Analysis of the primary endpoint will be performed for the intention to treat - exposed (ITT-E) population using the FDA snapshot method.

BACKGROUND: Three drug regimens for the treatment of HIV are widely used and successful in achieving viral suppression. However, they are associated with various adverse events including renal and bone disease, anaemia, mitochondrial toxicity, and possible association with increased cardiovascular events. Data from the ongoing B/F/TAF Elderly Switch Study has demonstrated high rates of renal insufficiency and osteoporosis in people living with HIV aged 60 years or more, hence the need for safe treatment options. Two drug regimens (2DR) have demonstrated non-inferiority to three drug regimens in patients who are treatment-naïve as well as in those who are virally suppressed on a first-line regimen and potentially have lower toxicity, fewer adverse drug events and a lower drug burden. OVERALL STRATEGY: This is a phase 3b, multi-centre, open-label, single-arm clinical trial over 96 weeks describing the efficacy of switching virally suppressed HIV-1 infected adults to DTG/3TC dual therapy from their current B/F/TAF regimen. The primary efficacy endpoint is the proportion of participants with viral load (VL) ≥ 50 copies/ml at week 48. The study will take place at two sites in Kenya: Kenyatta National Hospital (KNH, the largest teaching and referral hospital in Kenya), and Jaramogi Oginga Odinga Teaching and Referral Hospital (JOOTRH, the largest teaching and referral hospital in the Nyanza region of Kenya). The outpatient HIV clinics at these sites currently provide antiretroviral therapy (ART) to over 15,000 persons living with HIV (PWH) combined. These two sites are currently participating in the B/F/TAF-elderly study. Study visits will take place at screening, baseline, and weeks 4, 12, 24, 36, 48, and 96 (with a 6-week extension as required for confirming HIV-1 RNA levels within the FDA snapshot window). HIV-1 RNA viral load will be performed at screening and weeks 4, 12, 24, 48 and 96. If HIV-1 RNA is ≥ 50 copies/ml then a repeat test will be performed at least 2 weeks after the detectable result to confirm virological failure. If the repeat HIV-1 RNA result is ≥ 50 copies/ml this confirms protocol-defined virological failure (PDVF) and genotypic resistance testing will be performed for any repeat viral load ≥ 500 copies/ml. Other routine study investigations will include CD4 count, complete blood count, serum Cr, renal biomarkers, alanine transaminase (ALT), aspartate aminotransferase (AST), fasting lipids, fasting glucose and patient satisfaction questionnaires (HIVTSQ). METHODS: The anticipated sample size is 240 participants started on study treatment among patients on B/F/TAF therapy for at least 24 weeks and no prior virological failure (defined as two consecutive HIV-1 RNA viral loads ≥ 50 copies/ml separated by at least 2 weeks), with a viral load of \< 50 copies/ml for at least 12 weeks, and aged 60 years or above. All participants will be recruited from the pool of patients who are exiting the B/F/TAF-elderly trial at the two study sites. Those who provide written informed consent will be assessed for eligibility through review of their medical records, history and physical examination. Patients who provide informed consent and meet all eligibility criteria after screening investigations will be enrolled in the study within 28 days of the screening investigations and will complete baseline investigations (CD4 count, fasting lipid profile and fasting glucose). During the enrollment visit participants will be switched to DTG/3TC two drug regimen. Participants will be engaged in the study for 96 weeks plus up to 28 days between screening and enrolment, and a follow-up visit up to 28 days beyond the week 96 visit if required to confirm HIV-1 RNA within the FDA snapshot window.