Results of a study published in Open Forum Infectious Diseases show bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) is associated with high rates of initial virologic suppression among patients with HIV infection and substance use disorder (SUD) at increased risk for treatment nonadherence.

Investigators at the University of Nebraska Medical Center conducted the BASE study (NCT03998176), an open-label, single-arm, prospective phase 4 study. Included patients were adults (N=43) with HIV infection and SUD who were enrolled via convenience sampling. All patients had an HIV viral load of at least 1000 copies/mL. Patients were started on B/F/TAF and were monitored for adherence and viral load at baseline and at weeks 6, 12, 24, 36, and 48. Virologic suppression was defined as an HIV viral load of less than 50 copies/mL.

Among patients included in the analysis, the median age was 38.0 (range, 21.0-62.0) years, 79.1% were men, and 81.4% were White. In addition, 53.5% of patients had stable housing, 76.7% earned less than $15,000 annually, 55.9% were uninsured or covered by the AIDS Drug Assistance Program, and 95.3% reported methamphetamine use within the previous 6 months. A total of 12 patients were antiretroviral therapy (ART)-naive at baseline.

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At baseline, the median HIV viral load was 55,800 (range, 1212-2,280,000) copies/mL, the median CD4 T-cell count was 460 (range, 40-1653) cells/mm3, and 44.2% had any drug resistance.

At week 24, 86.0% of the patients remained in the study, with further decreases in the patient population observed by week 48 (72.1%). Divergence in care retention was observed at week 6, with a higher percentage of patients who were naive to ART lost to follow-up compared with ART-experienced patients (58.3% vs 87.1%, respectively).

Virologic suppression was achieved by 74.4% of the patients at week 24 and 48.8% at week 48, with overall rates of virologic suppression higher among those who were ART-naive vs ART-experienced (100.0% vs 54.5%; P =.029).

Intracellular tenofovir diphosphate levels were significantly higher at week 48 among patients who had vs had not achieved HIV virologic suppression (P =.008). Similar findings were observed in regard to subjective adherence rates, with higher rates observed among those who had (range, 83.8%-91.5%) vs had not (range, 59.0%-72.5%) achieved virologic suppression.

Treatment-emergent resistance was observed in 1 patient.

Severe adverse events occurred among 34.9% of the population. The most common events were suicidal ideation (11.6%), COVID-19 infection (4.7%), intractable headache (4.7%), neurosyphilis (4.7%), and acute kidney injury (4.7%). Among laboratory events, severe increases in creatinine (n=3) and blood glucose (n=1) levels were also observed.

During the study, the overall rate of methamphetamine use decreased by 29%. In addition, 7 patients were enrolled in intensive treatment programs for SUD, all of whom maintained HIV virologic suppression through week 48.

Limitations of this study include the small sample size and the single-arm and open-label design.

“While our data generally support B/F/TAF’s high barrier to resistance, it is important to note one participant with incomplete adherence developed emergent reverse transcriptase drug resistance,” the investigators noted.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Havens JP, Bares SH, Lyden E, et al. Effectiveness and safety of bictegravir/emtricitabine/tenofovir alafenamide in patients with HIV-1 infection and ongoing substance use disorder: the BASE study. Open Forum Infect Dis. 2023;10(3):ofad080. doi:10.1093/ofid/ofad080

This article originally appeared on Infectious Disease Advisor