Abstract
The effectiveness of daily, oral, tenofovir (TFV)-based HIV pre-exposure prophylaxis (PrEP) is highly dependent on adherence. Adolescent girls and young women (AGYW) ages 15-29 years in HIV endemic settings comprise a majority of new HIV infections and are a key population for PrEP. HIV also disproportionately affects youth in the United States, where young adults account for 19% of new HIV diagnoses. However, 50-80% of AGYW discontinue PrEP within one year and, among those who continue, adherence estimates are <20% over a year. Although the HIV prevention field has spent almost the past decade developing and testing PrEP adherence interventions, to date no intervention has effectively improved PrEP adherence among AGYW.
Long-acting HIV prevention options are on the horizon, but open-label extension studies have found that despite poor adherence and continuation rates, almost half of AGYW prefer daily oral PrEP pills to these options. Moreover, TFV-based PrEP is inexpensive and highly effective even with only 4 pills per week, will be included in multipurpose pregnancy and HIV prevention pills, and requires fewer clinic visits and less clinic staff to implement than long- acting options so will remain a key tool. Novel adherence support approaches for daily oral PrEP are still urgently needed to maximize the public health impact of this HIV prevention option.
In prior trials, AGYW and providers described desires for real-time, pharmacologic metrics of PrEP adherence alongside motivational counseling tailored to results (“drug-level feedback” or DLFB). DLFB approaches with plasma and dried blood spot samples for PrEP adherence measurement have failed to improve PrEP adherence largely due to delays in providing results and the need for costly equipment to analyze. Our team developed the first real-time PrEP adherence metric at the point-of-care (POC) which detects TFV in urine with high sensitivity and specificity. In a prior NIH-funded pilot trial with women >18 years in Kenya, use of the urine POC assay coupled with DLFB resulted in significantly higher short- and long-term PrEP adherence compared with standard-of-care (SOC).
The goal of this R01 is to build on our prior work to rigorously examine effectiveness of our assay among a younger population of AGYW with interest in oral PrEP and adherence challenges (N=400) and to assess its implementation and cost-effectiveness in real-world, high-volume PrEP programs in Kenya. We will leverage our long-standing partnership with Jomo Kenyatta University to achieve the following Aims in a hybrid effectiveness-implementation trial: 1) Assess effectiveness of a POC urine test for TFV with tailored DLFB on PrEP adherence versus SOC PrEP delivery alone among AGYW at PrEP clinics in Kenya; 2) Assess reach, adoption, implementation, and maintenance of the urine-based adherence intervention; and 3) Perform cost and cost-effectiveness analyses of the urine TFV assay incorporated into routine PrEP delivery. If successful, this trial will provide evidence to move our low-cost urine assay into PrEP programs for adolescents in both sub-Saharan Africa and the U.S. who have desires to use oral PrEP but difficulties adhering.
