UPenn Researchers Developed an Urine Test for Tenofovir to Monitor Adherence among people on PrEP

UPenn researchers suggested a low-cost urine test for point-of-care places to be an effective method to control adherence to medicines intake.

PrEP adherence is critical for its success in HIV prophylaxis programs, but unfortunately, doctors do not have still satisfactory methods to monitor adherence in real time. Self-report and pill counts are inaccurate methods for monitoring adherence, particularly in populations at high risk of acquiring HIV infection, such as young men of colour who have sex with men.

Dr. Helen Koenig from the Division of Infectious Diseases, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania aimed to develop and validate a urine assay to measure the concentration of TFV (the active metabolite of the prodrug TDF) to monitor adherence to PrEP in a clinical setting objectively. Dr. Koening team used a high-performance liquid chromatography–tandem mass spectrometry (LC-MS/MS) plasma and urine assay with high sensitivity and specificity for TFV.

This method was tested in a trial conducted from January 2014 to December 2014 at Philadelphia FIGHT, a community-based organization that provides comprehensive care to patients living with and at risk for HIV infection.

The outcomes were encouraging. Results of urine testing are available within one week, approximately the same turnaround time as viral load testing for HIV-positive patients, and there are no special processing requirements for urine samples after collection. Samples are stable at room temperature for up to 14 days.

Participants of the study were satisfied with the urine test as a means of monitoring adherence, with the side effects of urine testing, and with the demands of weekly testing. They found it to be convenient and were satisfied with their understanding of the importance of the test. They would recommend urine testing to others on PrEP and would be interested in continuing urine testing after the study.

"We provide proof of concept that a semiquantitative urine assay measuring levels of TFV could be further developed into a point-of-care test and be a useful tool to monitor adherence to PrEP," concludes Dr. Koenig.