INSTIs for the management of HIV-associated TB (INSIGHT study): a phase 2b study to evaluate the efficacy, safety and pharmacokinetics of a combination of bictegravir, emtricitabine and tenofovir alafenamide fumarate for the treatment of HIV-1 infection in patients with drug-susceptible tuberculosis on a rifampicin-based treatment regimen: a phase 2b open-label randomised controlled trial

Introduction Cotreatment of HIV and tuberculosis (TB) reduces morbidity and mortality in coinfected patients. Availability of antiretroviral treatment (ART) drug options, including within drug classes, is important, particularly in high HIV/TB burden low and middle-income countries.Methods and analysis This is a phase 2b, open-label, non-comparative randomised controlled trial to assess the antiretroviral activity of a fixed-drug, single tablet, combination of bictegravir (BIC) 50 mg/emtricitabine (FTC) 200 mg/tenofovir alafenamide (TAF) 25 mg (Biktarvy). The primary objective is to determine the efficacy, safety and pharmacokinetics of two times per day, coformulated BIC 50 mg/FTC 200 mg/TAF 25 mg in HIV-positive ART-naïve patients with TB who are receiving a rifampicin-based treatment regimen and to characterise viral suppression rates at week 24 through to week 48 in the BIC/FTC/TAF arm. We will enrol 120 patients randomised in a 2:1 ratio to the intervention or control arm of the study. A non-comparative contemporaneous control arm in which participants receive a dolutegravir-based regimen (standard of care) will also be enrolled.Ethics and dissemination The University of KwaZulu-Natal Biomedical Research Ethics Committee (BREC) and the South African Health Products Regulatory Authority (SAHPRA) have granted regulatory approval (trial reference numbers: BREC/00001300/2020 and SAHPRA 20200810). Trial results will be disseminated through conference presentations, peer-reviewed publications and the clinical trial registry.Trial registration number Clinicaltrials.gov; Trial registration number: NCT04734652; South African National Clinical Trials Register (SANCTR DOH-27-012021-6789)