Pre-exposure prophylaxis (PrEP) adherence remains a challenge among young men who have sex with men (MSM). We developed and tested a smartphone application ("app"), "DOT Diary", which combines automated directly observed therapy (DOT) with information about PrEP protection levels, pill-taking reminders, a sexual behavior diary, and a PrEP dosing calendar. To contextualize trial results, we qualitatively explored participants' app experiences. The trial enrolled 100 young MSM in San Francisco and Atlanta. Participants were randomized 2:1 to DOT Diary versus standard-of-care and followed for 24 weeks. Interviews were conducted with 24 intervention participants. Data were analyzed using a memo-writing approach. Most expressed overall satisfaction with the app ("it was good for its purpose"), despite concerns about technical glitches. The most popular app features were the monthly calendar showing days PrEP was taken and information about level of protection based on pills taken. The DOT component helped participants establish PrEP routines. The reminders were "annoying but effective" at motivating dosing. Opinions about the sexual behavior diary varied. Overall, DOT Diary was acceptable; participants were willing to use it daily to record pill-taking. Critical components included the information about PrEP protection levels and calendar, while others may be modified to improve future success.Trial registration: ClinicalTrials.gov identifier: NCT03771638.
Keywords: Pre-exposure prophylaxis (PrEP); SDG 10: Reduced inequalities; SDG 3: Good health and well-being; acceptability; directly observed therapy (DOT); mobile health (mHealth).