ATN 140: LYNX Number: NCT03177512

Study Summary:

Using the Information-Motivation-Behavior Skills (IMB) model, we have developed LYNX, a highly interactive mobile app to promote accurate risk perception and increase HIV/STI testing and linkage to care among young men who have sex with men (YMSM). Key components of the app include Sex Pro (a personalized HIV risk score), a sex diary to facilitate accurate data collection; HIV/STI testing information and reminders; access to home HIV/STI testing options; a geospatial-based locator of HIV/STI testing sites and PrEP clinics; PrEP information and videos; and online PrEP navigation. Features of the app will be finalized during the formative phase of this study.

The LYNX protocol will involve qualitative formative work through focus groups, to refine the LYNX app (Phase 1); an open technical pilot to optimize usability (Phase 2); and a pilot randomized controlled trial (RCT) to evaluate preliminary acceptability, feasibility, and preliminary efficacy (Phase 3) of the LYNX app.

Study Details:

Study Duration:

Formative work (Aim 1) will be conducted over 3-6 months. The technical pilot (Aim 2) will be enrolled over a 2-month period, and study follow-up will be 2 months. The pilot RCT (Aim 3) will be enrolled over several months, and study follow-up will be 6 months.

Sample Size:

Total sample size for this project will be up to 115 YMSM. Aim 1 will include 40 young men who have sex with men (YMSM) and who are not living with HIV. Aim 2 will include up to 15 YMSM. Aim 3 will enroll 60 YMSM, with 40 YMSM randomized to receive LYNX, and 20 YMSM randomized to receive standard or care.


  • Age 15-24 years old
  • Assigned male sex at birth and male-identified
  • Self-report being HIV uninfected or HIV status unknown at screening
  • Self-report having not had an HIV test in the past 3 months (for Aims 2 and 3 only)
  • Owns an iOS or Android mobile phone
  • More information on eligibility and exclusion criteria available on

Primary Objectives:

  1. To conduct qualitative, formative work to refine a mobile phone app, LYNX, to promote HIV/STI testing and PrEP uptake among YMSM.
  2. To conduct a technical pilot to optimize LYNX app functionality, technical performance, and user satisfaction.
  3. To conduct a pilot RCT to evaluate the feasibility and acceptability of LYNX to increase HIV/STI testing and PrEP uptake among YMSM.

Secondary Objectives:

  1. To compare the rate of HIV/STI testing in the LYNX intervention vs. control arms.
  2. To compare the rate of PrEP uptake in the LYNX intervention vs. control arms.
  3. To compare changes in sexual risk behaviors among YMSM in the LYNX intervention vs. control arms.

Protocol Chairs:

Albert Liu, MD, MPH
Hyman Scott, MD, MPH