Clinical trial NCT03881007: A Trial to Compare Antibacterial vs. Placebo Mouthwash to Reduce the Incidence of Sexually Transmitted Infections (STIs) in Men Who Have Sex With Men (MSM) Taking HIV Pre-Exposure Prophylaxis (PrEP)
Official title: A Double-blind Single Center, Crossover, Randomized Controlled Trial of Antibacterial vs. Placebo Mouthwash to Reduce the Incidence of Gonorrhea/Chlamydia/Syphilis in MSM Taking HIV Pre-exposure Prophylaxis (PrEP)
Study type: INTERVENTIONAL
Overall status: TERMINATED
Phase: NA
Conditions: Sexually Transmitted Diseases
Keywords: Gonorrhea
Syphilis
Chlamydia
Listerine
STI
Lead sponsor: Institute of Tropical Medicine, Belgium
Sponsor class: OTHER
First posted: 2019-03-19
Enrollment: 343
Sex: MALE
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: PREVENTION

Brief summary: The study involves a randomized placebo controlled trial that aims to assess if a mouthwash (Listerine cool mint, LCM) is able to reduce the cumulative incidence of gonorrhoea (Ng), chlamydia (Ct) and syphilis in men who have sex with men and receiving preexposure prophylaxis (PrEP) at the Institute of Tropical Medicine (ITM).

Detailed description: The study aims to assess if there is a difference in the incidence rate of gonorrhea, chlamydia and syphilis detected at any site whilst individuals are on daily and pre/post sex Listerine cool mint (LCM) vs. placebo mouthwash.

The study has a double-blind, cross-over design, in which subjects will be screened at the ITM and, if eligible, will be enrolled and randomized to group 1 (LCM) or group 2 (placebo). After 3 months, a crossover will occur and subjects will switch to the other intervention. Each participant will therefore be enrolled for 6 months (2 x 3 months, no wash out period).

Subjects will be recruited from the existing PrEP cohort at the Institute of Tropical Medicine Antwerp. A total of 320 subjects will be recruited (160 in each arm).

Eligibility criteria: Inclusion Criteria:

* Men aged 18 or more
* Enrolled in Belgian PrEP program at ITM
* Has had sex with another man in the previous year
* Has had a symptomatic or asymptomatic STI (Ct/Ng/syphilis) in the previous 2 years
* Willing to be enrolled in the cohort for 6 months and attend 3 monthly follow up visits
* Willing to comply with the mouthwash study schema and willing to ask their casual partners to mouthwash pre- and post-sex
* Prepared to fill out the online diary once a week
* Able and willing to provide written informed consent

Exclusion Criteria:

* Currently using a mouthwash and unwilling to cease use of this mouthwash
* Enrolment in another interventional trial
* Tests HIV positive at screening

Primary outcomes:
measure: Patient Counts of Ng Plus Ct Plus Syphilis in Each Study Arm for Each Period
timeFrame: 3-month period following each intervention
Secondary outcomes:
measure: Difference in Incidence Rate of Pharyngeal Ng Between Each Study Arm for Each Period
timeFrame: 3-month period following each intervention
measure: Difference in Incidence Rate of Ct (Combined Pharyngeal, Urethral and Rectal) Between Each Study Arm for Each Period
timeFrame: 3-month period following each intervention
measure: Difference in Incidence Rate of Syphilis Between Periods on LCM vs. Placebo
timeFrame: 3-month period following each intervention
measure: Proportion of Days That Mouthwash is Used on a Daily Basis and Proportion of Casual Sex Contacts When Mouthwash is Used Pre or Post Sex
timeFrame: 6-month period
measure: Difference in Incidence Rate of Ng Plus Ct Plus Syphilis Between LCM and Placebo After Controlling for Adherence With Daily and Pre/Post Sex Mouthwash
timeFrame: 3-month period following each intervention
measure: Difference in Cumulative Numbers of Antibiotics Used Between Periods on LCM vs. Placebo
timeFrame: 3-month period following each intervention
Other outcomes:
Locations:
city: Antwerp
country: Belgium
facility: Institute of Tropical Medicine
Study officials:
affiliation: Institute of Tropical Medicine Antwerp
name: Chris Kenyon, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Van Dijck C, Tsoumanis A, Rotsaert A, Vuylsteke B, Van den Bossche D, Paeleman E, De Baetselier I, Brosius I, Laumen J, Buyze J, Wouters K, Lynen L, Van Esbroeck M, Herssens N, Abdellati S, Declercq S, Reyniers T, Van Herrewege Y, Florence E, Kenyon C. Antibacterial mouthwash to prevent sexually transmitted infections in men who have sex with men taking HIV pre-exposure prophylaxis (PReGo): a randomised, placebo-controlled, crossover trial. Lancet Infect Dis. 2021 May;21(5):657-667. doi: 10.1016/S1473-3099(20)30778-7. Epub 2021 Mar 4.