# PrEPmate 211: Developing a mobile app to support the safe and effective use of on-demand PrEP among MSM in the US

> **NIH NIH R34** · PUBLIC HEALTH FOUNDATION ENTERPRISES · 2021 · $190,454

## Abstract

Project Summary/Abstract
Men who have sex with men (MSM) are the population most affected by HIV in the United States, accounting
for over two-thirds of all new HIV diagnoses. Pre-exposure prophylaxis (PrEP) has demonstrated high levels of
efficacy for HIV prevention, however, PrEP initiations have been low nationwide, and discontinuation rates are
high. On-demand PrEP, or the use of oral PrEP before/after sex, has been shown to be highly effective in
clinical trials and real-world practice and has been endorsed by the International Antiviral Society-USA and
World Health Organization. MSM in the US not interested in taking a daily pill have expressed high levels
interest in on-demand PrEP, and several clinics have begun offering on-demand PrEP as an alternative to
daily PrEP. However, there are substantial concerns about adherence to this complex regimen (2 pills 2-24
hours before sex, 1 pill 24 and 48 hours later). Tools to support individuals who choose to use on-demand
PrEP are critical to ensure effectiveness and minimize harm of on-demand dosing. In this R34 application, we
propose to develop and refine a mobile app, PrEPmate 211, to support the safe and effective use of on-
demand PrEP among US MSM. Grounded in the situated Information, Motivation, Behavioral Skills model, this
app will feature 1) "PrEP 211 Basics" providing information on how to take on-demand PrEP; 2) motivational
weekly check-in messages to provide support; 3) a sexual and pill-taking diary, with reminders for pre/post-sex
doses and display showing time to protection; and 4) a shared decision-making tool on whether to continue on-
demand PrEP or switch to daily PrEP. In aim 1, we will assess patient and provider-identified barriers and
facilitators of on-demand PrEP use through focus groups with 20 MSM and interviews with 5-7 clinical
providers, and elicit their feedback to inform the development of PrEPmate 211. In aim 2, we will conduct a 2
month optimization pilot among 12-15 MSM taking on-demand PrEP to refine the functionality, technical
performance, and user satisfaction of the app. In aim 3, we will conduct a pilot randomized controlled trial to
evaluate the feasibility, acceptability, and preliminary impact of PrEPmate 211 to increase PrEP coverage of
sex acts. In this trial, we will enroll 60 MSM currently taking or interested in starting on-demand PrEP who will
be randomized 2:1 to receive PrEPmate 211 (N=40) or enhanced standard of care (brochure and counseling
on on-demand PrEP with bottle timer cap showing time of last dose, N=20). Feasibility and acceptability of the
app will be assessed through app paradata of usage patterns and the System Usability Scale. Preliminary
impact will be assessed by evaluating the proportion of sex acts covered by PrEP assessed via sex/dosing
data entered into PrEPmate 211 or a web app; we will also pilot the use of a novel urine tenofovir self-test strip
to confirm PrEP dosing in the past week. Upon project completion, we will...

## Key facts

- **NIH application ID:** 10242038
- **Project number:** 5R34MH121139-03
- **Recipient organization:** PUBLIC HEALTH FOUNDATION ENTERPRISES
- **Principal Investigator:** Albert Ying-Hwa Liu
- **Activity code:** R34 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $190,454
- **Award type:** 5
- **Project period:** 2019-09-01 → 2024-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10242038

## Citation

> US National Institutes of Health, RePORTER application 10242038, PrEPmate 211: Developing a mobile app to support the safe and effective use of on-demand PrEP among MSM in the US (5R34MH121139-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10242038. Licensed CC0.

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