The Efficacy of Doxycycline Post Exposure Prophylaxis for Preventing STIs Among MSM in Bangkok, Thailand.

NCT07397403 | Recruiting Phase 4

• 1 other identifier: 1/2568
• Study Type: interventional
• Target: 400
• Locations: 1 country
• Sites: 1

Brief Summary

The objective of this research is to evaluate the efficacy and safety of doxycycline in MSM for preventing sexually transmitted infections (gonorrhea, chlamydia, and syphilis) in Thailand Participation in this study will last approximately 12 weeks and will include 2-3 clinic visits, along with 10-11 follow-up phone contacts over a period of 11 weeks.

Conditions

Syphilis Infection; Gonorrhea; Chlamydia

Keywords

DoxyPEP; MSM; Syphilis; gonorrhea; Chlamydia; Prevention

Outcome Measures

Primary Outcomes (1)

• To evaluate the efficacy of doxycycline in preventing sexually transmitted infections (gonorrhea, chlamydia, and syphilis) among men who have sex with men in Thailand.

  Measure the proportion of participants who test positive by NAAT for gonorrhea or chlamydia at any anatomical site (genital, pharyngeal, or rectal), or who are diagnosed with syphilis during the study period.

  12 weeks

Study Arms (2)

DoxyPEP arm

EXPERIMENTAL

Participants will receive DoxyPEP for STIs prophylaxis in this arm

Drug: Doxycycline (200mg/day)

Control arm

NO INTERVENTION

Participants will receive standard STIs prevention

Interventions

Doxycycline (200mg/day) DRUG

Doxycycline 200 mg single dose after unprotected sex within 24-72 hours

DoxyPEP arm

Eligibility Criteria

• Age: 18 Days - 60 Days
• Gender Eligibility Details: Men who have sex with men
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• Biological male, aged not over 60 years
• Thai nationality
• Able to read, communicate, and understand the Thai language
• Men who have sex with men (MSM), aged 18 years or older and not over 60 years
• Having at least one of the following risk factors:
• A history of condomless sex, or condom failure (breakage, leakage, or slippage), via any sexual route with at least two sexual partners within the past 3 months
• A diagnosis of gonorrhea, chlamydia, or syphilis within the past 6 months
• Current use of HIV pre-exposure prophylaxis (PrEP)
• Willing and able to participate in study procedures (e.g., able to return to the clinic for scheduled testing for gonorrhea, chlamydia, and syphilis; able to complete doxycycline use records; and able to receive follow-up phone calls from the research team)
• Willing and able to provide written informed consent to participate in the study

You may not qualify if:

• History of allergy to tetracycline-class antibiotics
• Diagnosed with syphilis and not yet treated, or currently receiving treatment with benzathine penicillin G or doxycycline
• Receipt of benzathine penicillin G within the past 12 weeks
• Prior receipt of a gonorrhea vaccine
• Current use of medications or products that may interact with doxycycline, including:
• Vitamin A derivatives (e.g., isotretinoin, acitretin)
• Antiepileptic drugs (e.g., phenytoin, carbamazepine, phenobarbital)
• Immunosuppressive agents (e.g., methotrexate)
• Medications for heart failure or cardiac arrhythmias (e.g., digoxin)
• Anticoagulants (e.g., warfarin)
• Use of oral or injectable medications that affect blood cells, such as anticancer drugs, chemotherapy, systemic corticosteroids, or targeted therapies
• History of renal impairment (eGFR \< 60 mL/min/1.73 m²) or hepatic impairment (AST or ALT \> 3 times the upper limit of normal)
• Uncontrolled or unstable underlying diseases, such as hematologic disorders, cancer, autoimmune diseases, or neurological disorders
• Severe medical or psychiatric conditions that, in the investigator's judgment, may increase study-related risk or impair the participant's ability to provide informed consent
• Alcohol dependence (inability to control alcohol consumption, withdrawal symptoms upon reduction or cessation, or continued use despite harm) or illicit drug dependence (regular, uncontrolled use) within the past 12 months prior to enrollment, which may affect doxycycline use for STI prevention

Sponsors & Collaborators

• Bangrak STIs Center: lead
• Mahidol University: collaborator

Study Sites (1)

Bangrak STIs Center

Sathorn, Bangkok, 10120, Thailand

RECRUITING

Related Publications (12)

• Frederiks WM, Kummerlin IP, Bosch KS, Vreeling-Sindelarova H, Jonker A, Van Noorden CJ. NADPH production by the pentose phosphate pathway in the zona fasciculata of rat adrenal gland. J Histochem Cytochem. 2007 Sep;55(9):975-80. doi: 10.1369/jhc.7A7222.2007. Epub 2007 May 28.

  PMID: 17533217 BACKGROUND

• Ren Z, Zhang P, Wang H, Wang H. Qualitative research investigating the mental health care service gap in Chinese burn injury patients. BMC Health Serv Res. 2018 Nov 28;18(1):902. doi: 10.1186/s12913-018-3724-3.

  PMID: 30486854 BACKGROUND

• Liu Q, Tong D, Yuan W, Liu G, Yuan G, Lan W, Zhang D, Zhang J, Huang Z, Zhang Y, Jiang J. Different RET gene mutation-induced multiple endocrine neoplasia type 2A in 3 Chinese families. Medicine (Baltimore). 2017 Jan;96(3):e5967. doi: 10.1097/MD.0000000000005967.

  PMID: 28099363 BACKGROUND

• Peyriere H, Makinson A, Marchandin H, Reynes J. Doxycycline in the management of sexually transmitted infections. J Antimicrob Chemother. 2018 Mar 1;73(3):553-563. doi: 10.1093/jac/dkx420.

  PMID: 29182717 BACKGROUND

• Stewart J, Oware K, Donnell D, Violette LR, Odoyo J, Soge OO, Scoville CW, Omollo V, Mogaka FO, Sesay FA, McClelland RS, Spinelli M, Gandhi M, Bukusi EA, Baeten JM; dPEP Kenya Study Team. Doxycycline Prophylaxis to Prevent Sexually Transmitted Infections in Women. N Engl J Med. 2023 Dec 21;389(25):2331-2340. doi: 10.1056/NEJMoa2304007.

  PMID: 38118022 RESULT

• Molina JM, Bercot B, Assoumou L, Rubenstein E, Algarte-Genin M, Pialoux G, Katlama C, Surgers L, Bebear C, Dupin N, Ouattara M, Slama L, Pavie J, Duvivier C, Loze B, Goldwirt L, Gibowski S, Ollivier M, Ghosn J, Costagliola D; ANRS 174 DOXYVAC Study Group. Doxycycline prophylaxis and meningococcal group B vaccine to prevent bacterial sexually transmitted infections in France (ANRS 174 DOXYVAC): a multicentre, open-label, randomised trial with a 2 x 2 factorial design. Lancet Infect Dis. 2024 Oct;24(10):1093-1104. doi: 10.1016/S1473-3099(24)00236-6. Epub 2024 May 23.

  PMID: 38797183 RESULT

• Luetkemeyer AF, Donnell D, Dombrowski JC, Cohen S, Grabow C, Brown CE, Malinski C, Perkins R, Nasser M, Lopez C, Vittinghoff E, Buchbinder SP, Scott H, Charlebois ED, Havlir DV, Soge OO, Celum C; DoxyPEP Study Team. Postexposure Doxycycline to Prevent Bacterial Sexually Transmitted Infections. N Engl J Med. 2023 Apr 6;388(14):1296-1306. doi: 10.1056/NEJMoa2211934.

  PMID: 37018493 RESULT

• Molina JM, Charreau I, Chidiac C, Pialoux G, Cua E, Delaugerre C, Capitant C, Rojas-Castro D, Fonsart J, Bercot B, Bebear C, Cotte L, Robineau O, Raffi F, Charbonneau P, Aslan A, Chas J, Niedbalski L, Spire B, Sagaon-Teyssier L, Carette D, Mestre SL, Dore V, Meyer L; ANRS IPERGAY Study Group. Post-exposure prophylaxis with doxycycline to prevent sexually transmitted infections in men who have sex with men: an open-label randomised substudy of the ANRS IPERGAY trial. Lancet Infect Dis. 2018 Mar;18(3):308-317. doi: 10.1016/S1473-3099(17)30725-9. Epub 2017 Dec 8.

  PMID: 29229440 RESULT

• Nanthaprut P, Manojai N, Chanlearn P, Mattawanon N, Chiawkhun P, Homkham N, Traisathit P. Comparison of HIV-Positive Incidence Among Transgender Women and Men Who Have Sex with Men at Stand-Alone and Mobile Voluntary Counseling and Testing Facilities in Chiang Mai Province, Thailand. AIDS Patient Care STDS. 2021 Apr;35(4):116-125. doi: 10.1089/apc.2020.0258.

  PMID: 33835852 RESULT

• Chen JS, Levintow SN, Tran HV, Sripaipan T, Nguyen MX, Nguyen SM, Miller WC, Go VF, Giang LM. HIV and STI prevalence and testing history among men who have sex with men in Hanoi, Vietnam. Int J STD AIDS. 2022 Feb;33(2):193-201. doi: 10.1177/09564624211060185. Epub 2021 Dec 1.

  PMID: 34852691 RESULT

• Nguyen TV, Tran HP, Khuu NV, Nguyen PD, Le TN, Hoang CD, Tran T, Le TQ, Pham QD, Phan LT. Increases in both HIV and syphilis among men who have sex with men in Vietnam: Urgent need for comprehensive responses. Int J STD AIDS. 2021 Dec;32(14):1298-1307. doi: 10.1177/09564624211036421. Epub 2021 Aug 14.

  PMID: 34392717 RESULT

• Johnston LG, Soe P, Widihastuti AS, Camellia A, Putri TA, Rakhmat FF, Nurwandani RA, Prabhu SM, Sulaiman N, Pronyk PM. Alarmingly High HIV Prevalence Among Adolescent and Young Men Who have Sex with Men (MSM) in Urban Indonesia. AIDS Behav. 2021 Nov;25(11):3687-3694. doi: 10.1007/s10461-021-03347-0. Epub 2021 Jun 18.

  PMID: 34143341 RESULT

Related Links

• Sexually transmitted infections (STIs) \[Internet\]. Who.int. \[cited 2024 Sep 24\].
• Center for Disease Control and Prevention. Sexually transmitted infections (STIs). \[cited 2024 Sep 24\]
• CDC clinical guidelines on the use of doxycycline postexposure prophylaxis for bacterial sexually transmitted infection prevention, United States, 2024

MeSH Terms

Conditions

Gonorrhea; Chlamydia Infections; Syphilis

Interventions

Doxycycline

Condition Hierarchy (Ancestors)

Neisseriaceae Infections; Gram-Negative Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Infections; Sexually Transmitted Diseases, Bacterial; Sexually Transmitted Diseases; Communicable Diseases; Genital Diseases; Urogenital Diseases; Chlamydiaceae Infections; Treponemal Infections; Spirochaetales Infections

Intervention Hierarchy (Ancestors)

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

Study Officials

• Rossaphorn KITTIYAOWAMARN, MD

  Bangrak STIs Center

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Rossapnorn Kittiyaowamarn, MD

CONTACT

+66814501066; rossaphorn@gmail.com

Kittipoom Chinhiran, MD

CONTACT

+66863583077; x_destiny_war@hotmail.com

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: Labotatory staffs
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Chief of Bangrak STIs Center

Model Details: This study is designed as a randomized controlled trial (RCT). Participants will be randomly assigned to either the intervention group or the control group in a 2:1 ratio using simple randomization. The intervention group will receive doxycycline for the prevention of sexually transmitted infections (gonorrhea, chlamydia, and syphilis) for a period of 3 months. The control group will receive standard-of-care services and a brief educational session on sexually transmitted infection prevention at the start of the study. All participants will be tested for bacterial sexually transmitted infections (syphilis, gonorrhea, and chlamydia) at baseline and again at the end of the study after completing 12 weeks of follow-up. Before randomization, eligible participants will complete a questionnaire assessing knowledge, attitudes, and preventive behaviors related to sexually transmitted infections. In-depth interviews will also be conducted among men who have sex with men (MSM) at risk due

Study Record Dates

• First Submitted: February 2, 2026
• First Posted: February 9, 2026
• Study Start: October 6, 2025
• Primary Completion (Estimated): October 5, 2026
• Study Completion (Estimated): May 31, 2027
• Last Updated: February 9, 2026

Record last verified: 2025-10

Data Sharing

• IPD Sharing: Will not share

Locations

TH (1)