Bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) is a single pill regimen that was approved by the FDA in February 2018 for treatment of HIV. The marketed name of the drug is Biktarvy. In two phase 3 comparative clinical trials, including one with ABC/3TC/DTG, it was found to be non-inferior to dolutegravir-containing regimens in terms of virologic outcomes. B/F/TAF was also well tolerated, with few discontinuations for adverse events. As a result, B/F/TAF is an ideal non-abacavir containing regimen to assess the effect of removing ABC on coronary flow reserve.

Positron emission tomography (PET) imaging allows precise and reproducible quantification of myocardial blood flow, thereby providing a direct assessment of coronary vascular health. Coronary flow reserve (CFR, calculated as the ratio of peak hyperemic myocardial blood flow over that at rest) is emerging as a powerful quantitative prognostic imaging marker of clinical cardiovascular risk. CFR provides a robust and reproducible clinical measure of the integrated hemodynamic effects of epicardial coronary artery disease (CAD), diffuse atherosclerosis, vessel remodeling, and microvascular dysfunction resulting from endothelial cell dysfunction on myocardial tissue perfusion across the entire coronary circulation. These processes have direct relevance to the underlying vascular pathobiology in patients with HIV infection. Consequently, quantitative CFR provides a unique opportunity to examine the potential impact of novel therapies on the biology of the disease and its association with cardiovascular outcomes. By testing the fundamental concept of whether novel ART therapies in HIV can lead to improved coronary blood flow and myocardial tissue perfusion, TAF-CFR would provide important mechanistic insights of the capabilities of TAF therapy to improve key determinants of clinical risk.

This is an open label, multicenter, uncontrolled, single arm pilot study. Patients with stable HIV currently treated with abacavir/lamivudine/dolutegravir STR regimens will be eligible for the B/F/TAF-CFR study. PET scans will be performed after enrollment while on the abacavir/lamivudine/dolutegravir STR regimen and at 24 weeks after the switch to B/F/TAF regimen. Patients will be encouraged to remain on stable medical therapy throughout the enrollment period.

Inclusion Criteria:

Patients with HIV on abacavir/lamivudine/dolutegravir STR regimens for at least 1 year fulfilling the following inclusion criteria:

1. age ≥ 45 years for men and ≥ 55 years for women;
2. at least one coronary risk factor including smoking, dyslipidemia, hypertension, obesity (BMI >30) or diabetes, or a calculated 10-year risk of heart attack of 7.5% or higher;
3. HIV RNA < 200 copies/mL at last clinical measurement, done within the past 12 months prior to screening, with no intervening HIV RNA > 200;
4. Screening HIV RNA < 50 copies/mL, CBC, and chemistries that, in the judgment of the investigator, do not preclude the use of Biktarvy.

Exclusion Criteria:

1. patients not fulfilling inclusion criteria;
2. unstable HIV disease or other medical condition that, in the opinion of the investigator, would interfere with the conduct of the study;
3. history of cardiomyopathy (LVEF <40%) or significant valvular heart disease;
4. cirrhosis;
5. end stage renal disease on dialysis;
6. uncontrolled hypertension (defined as SBP >200 or DBP >110);
7. pregnancy;
8. Patients requiring medications contraindicated with the components of B/F/TAF;
9. Patients on active treatment for severe asthma or severe COPD.

Adverse Event data was collected from consent through 24-week End of Treatment visit.