Randomized Directly Observed Therapy Study to Interpret Clinical Trials of Doxy-PEP

NCT06414408 | Recruiting Early Phase 1 DMC FDA Drug

• 2 other identifiers: AI186641R01AI186641
• Study Type: interventional
• Target: 48
• Locations: 1 country
• Sites: 1

Brief Summary

Rates of bacterial sexually transmitted infections (STIs) are rising globally, demanding innovative interventions beyond the scope of current efforts to prevent STIs. The United States Doxycycline Post-exposure Prophylaxis (DoxyPEP) Study has demonstrated the efficacy of doxycycline post-exposure prophylaxis (PEP) among men who have sex with men and transgender women; but puzzlingly, doxycycline PEP was found ineffective in cisgender women in the Kenyan doxycycline Post-Exposure Prophylaxis (dPEP) study, with preliminary data suggesting the low medication adherence may explain the null result. By study end, the investigators will have developed adherence measurement methods for doxycycline in hair, blood, and urine, and will use these techniques to help interpret the Kenyan dPEP study, and to examine the relative performance of these methods within the United States DoxyPEP trial, establishing adherence metrics for current and future rollout studies of doxycycline post-exposure prophylaxis

Conditions

Sexually Transmitted Diseases, Bacterial

Outcome Measures

Primary Outcomes (3)

• Hair Doxycycline Concentration

  Doxycycline concentrations will be measured using liquid chromatography tandem mass spectrometry within hair samples for each of the four dosing patterns within an intensive washout pharmacokinetic phase following initial dosing.

  4 weeks

• Plasma Doxycycline Concentration

  Doxycycline concentrations will be measured using liquid chromatography tandem mass spectrometry within plasma samples for each of the four dosing patterns within an intensive washout pharmacokinetic phase following initial dosing.

  4 weeks

• Urine Doxycycline Concentration

  Doxycycline concentrations will be measured using liquid chromatography tandem mass spectrometry within urine samples for each of the four dosing patterns within an intensive washout pharmacokinetic phase following initial dosing.

  4 weeks

Study Arms (4)

Daily Dosing

ACTIVE COMPARATOR

Participants will be randomized to take once daily doxycycline 200mg for six weeks.

Drug: Doxycycline Pill

Three-times Weekly Dosing

ACTIVE COMPARATOR

Participants will be randomized to take one doxycycline 200mg dose three times a week (Monday, Wednesday, and Friday) for six weeks.

Drug: Doxycycline Pill

Weekly Dosing

ACTIVE COMPARATOR

Participants will be randomized to take one doxycycline 200mg dose once week.

Drug: Doxycycline Pill

Every Other Week Dosing

ACTIVE COMPARATOR

Participants will be randomized to take one doxycycline 200mg dose every other week.

Drug: Doxycycline Pill

Interventions

Doxycycline Pill DRUG

200mg Dose

Daily Dosing; Every Other Week Dosing; Three-times Weekly Dosing; Weekly Dosing

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• not currently at risk of a sexually transmitted infection and willing to use other methods, such as condoms, for STI prevention;
• if diagnosed with an STI in the past two years and/or a partner was diagnosed with an STI in the past year, is willing to use condoms for STI prevention;
• willing to provide hair, blood, and urine samples;
• not currently enrolled in other STI prevention studies;
• able to speak English
• transgender women participants should be currently using estrogen gender affirming hormone therapy with blood estrogen levels demonstrating consistent use
• transgender men participants should be currently using testosterone gender affirming hormone therapy with blood testosterone levels demonstrating consistent use
• able to provide a hair sample of \~50-100 strands of hair that are non-gray, not bleached, and at least 1cm in length
• willing to NOT shave hair or have a very short haircut or apply bleach for the duration of the study
• has suitable venous access for consecutive blood draws

You may not qualify if:

• any health condition that may interfere with participation or the ability to provide informed consent, including any debilitating or life-threatening conditions;
• pregnancy or plans to become pregnant;
• liver cirrhosis or fulminant liver disease;
• known hypersensitivity reaction to doxycycline.
• detectable doxycycline in hair at enrollment.
• unable to provide a hair sample of \~50-100 strands of hair that are non-gray, not bleached, and at least 1cm in length
• does not have suitable venous access for consecutive blood draws

Sponsors & Collaborators

• University of California, San Francisco: lead
• National Institute of Allergy and Infectious Diseases (NIAID): collaborator

Study Sites (1)

University of California, San Francisco/San Francisco General Hospital

San Francisco, California, 94110, United States

RECRUITING

MeSH Terms

Conditions

Sexually Transmitted Diseases, Bacterial

Interventions

Doxycycline

Condition Hierarchy (Ancestors)

Bacterial Infections; Bacterial Infections and Mycoses; Infections; Sexually Transmitted Diseases; Communicable Diseases; Genital Diseases; Urogenital Diseases; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Tetracyclines; Naphthacenes; Polycyclic Aromatic Hydrocarbons; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons; Organic Chemicals; Polycyclic Compounds

Study Officials

• Matthew Spinelli, MD, MAS

  University of California, San Francisco

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Shivani Mahuvakar

CONTACT

415-878-6384; DOTDoxyPEP@ucsf.edu

Study Design

• Study Type: interventional
• Phase: early phase 1
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Participants will be randomized to one of 4 doxycycline dosing patterns (daily, 3x weekly, weekly, every other week) and then will crossover to an alternate pattern once during the study.

Study Record Dates

• First Submitted: May 9, 2024
• First Posted: May 16, 2024
• Study Start: October 18, 2024
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): September 1, 2028
• Last Updated: April 13, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)