Emtricitabine/tenofovir alafenamide usage in a Scottish sexual health service providing HIV pre-exposure prophylaxis: A service evaluation

Background: In this service evaluation we evaluate the usage of emtricitabine and tenofovir alafenamide (FTC-TAF) in a large Scottish sexual health service providing Human Immunodeficiency Virus (HIV) Pre-Exposure Prophylaxis (PrEP) over a one-year period (May 2022-May 2023).Purpose: We evaluated the use of FTC-TAF as it is 30 times more expensive per 30 tablet supply than emtricitabine/tenofovir disoproxil (FTC-TDF). We sought to establish: - Number of patients initiated on FTC-TAF - Reasons for FTC-TAF initiation - Adherence to FTC-TAF.Results: Out of a total cohort of 1744 patients on HIV PrEP as of May 2023, seven patients (0.4%) had been initiated on FTC-TAF. The remainder (99.6%) were taking FTC-TDF. The majority of patients (n = 6) were initiated on FTC-TAF due to renal reasons, one patient was initiated FTC-TAF for bone mineral density concerns.Conclusions: All of the patients met eligibility criteria. In terms of adherence, three patients were regular attenders, two patients used FTC-TAF sporadically, and two had initiated and subsequently discontinued FTC-TAF altogether at the time of data analysis. FTC-TAF utilisation was lower than anticipated, initiated apropriately, and followed similar adherence patterns to FTC-TDF users. This will be helpful for financial forecasting and in the development of services where FTC-TAF is newly commissioned.