for males ages 18 years and up (full criteria)
Healthy Volunteers
healthy people welcome
study started
completion around
Principal Investigator
by Mallory Johnson, PhD (ucsf)
Headshot of Mallory Johnson
Mallory Johnson



This multi-site randomized controlled trial enrolling sexual minority men who use stimulants and are currently taking pre-exposure prophylaxis (PrEP). This randomized controlled trial will test the efficacy of a PrEP Affect Regulation Treatment Innovation (PARTI) condition comprised of a 5-session positive affect intervention delivered during smartphone-based Contingency Management (CM) for directly observed PrEP doses (PARTI+CM) compared to an attention-control condition delivered during CM. The primary outcome is HIV acquisition risk measured using a combination of tenofovir-diphosphate levels in dried blood spots that are indicative of sub-optimal adherence to PrEP and recent condomless anal sex.

Official Title

Optimizing PrEP Adherence in Sexual Minority Men Who Use Stimulants


Medication Adherence, HIV Prevention, Stimulant Use, Sexual Minority Men, HIV, PrEP Adherence, Contingency Management, PARTI, Contingency Management for PrEP Adherence, PARTI and CM (Contingency Management)


You can join if…

Open to males ages 18 years and up

  • Assigned male at birth
  • Identifies as male or gender non-conforming
  • Age 18 or older
  • Reads and speaks English
  • Past 6 months, reports condomless anal sex (CAS) with men
  • HIV negative
  • Currently has an active prescription for daily oral PrEP for at least 2 months and reports any non-adherence in the past month OR was initiated on PrEP in the past 2 months, regardless of reported adherence
  • Has an iPhone or Android smartphone
  • Screens positive for a moderate or severe stimulant use disorder with an abbreviated version of the Alcohol, Smoking, and Substance Involvement Screening Test (ASSIST) (total score of 4 or more) OR reports weekly use of either methamphetamine or cocaine.
  • Lives in California or Florida

You CAN'T join if...

  • Unable to provide informed consent
  • Unwilling to participate in smartphone-based CM for directly observed PrEP doses
  • Identifies as transfeminine (e.g., transgender woman)
  • Assigned female at birth
  • Unwilling to provide dried blood spot (DBS) specimen - either in-person or remotely
  • Plans to move out of the state in the next 6 months
  • Not taking PrEP daily (e.g., if taking intermittent 2-1-1 dosing)
  • Switched from Truvada to Descovy in the last 5 months


  • University of California, San Francisco accepting new patients
    San Francisco California 94143 United States
  • University of Miami Miller School of Medicine accepting new patients
    Miami Florida 33136 United States

Lead Scientist at University of California Health

  • Mallory Johnson, PhD (ucsf)
    Mallory Johnson is professor of medicine and nursing at UCSF and a licensed clinical health psychologist, whose research has focused on understanding, measuring, and improving the health of patients with chronic diseases such as HIV. His program of multidisciplinary collaborative research is focused on HIV prevention and improving HIV treatment outcomes through patient empowerment.


accepting new patients
Start Date
Completion Date
Florida International University
Study Type
Expecting 240 study participants
Last Updated