UC San Diego

Background

Daily oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) is effective for reducing human immunodeficiency virus (HIV) acquisition among cisgender women. We report results from the first US observational open-label demonstration project of pre-exposure prophylaxis (PrEP) among at-risk cisgender women.

Methods

Adherence Enhancement Guided by Individualized Texting and Drug Levels was a 48-week, single-arm, open-label demonstration study of daily oral TDF/FTC in cisgender women ≥18 years old at risk for HIV. Adherence was supported using 2-way text messaging and titrated adherence counseling based on rapid-turnaround tenofovir diphosphate concentrations from dried blood spots. Study visits occurred at baseline, weeks 4 and 12, and quarterly through week 48. Outcomes included TDF/FTC adherence, retention, and persistence.

Results

From June 2016 to October 2018, 136 cisgender women enrolled (mean age, 40 years (standard deviation, 11); 38% non-Hispanic Black and 19% Latina). At 48 weeks, 84 (62%) participants were retained and 62 (46%) remained on PrEP. More than one-third (12/31) of those on study but off PrEP throughout the study discontinued TDF/FTC because of side effects, and 1 adverse event led to study discontinuation. Of 120 participants with drug concentrations measured, 67 (56%) had at least 1 concentration consistent with 6 doses/week; 22 (18%) had consistent ≥6 doses/week across all study visits attended. There were no incident HIV infections and 4 incident bacterial sexually transmitted infections.

Conclusion

Adequate PrEP adherence for protective drug concentrations was not achieved for most study participants. More work needs to be done to fully explicate the reasons for nonadherence and low retention in cisgender women.