Comparisons of Treatment Responses of Early Syphilis to Benzathine Penicillin G With or Without Doxycycline

NCT06069141 | Recruiting

• 1 other identifier: 202305061MINA
• Study Type: interventional
• Target: 688
• Locations: 1 country
• Sites: 9

Brief Summary

This randomized controlled superiority study will be conducted during 2023-2025. The eligible participants are adult people living with HIV (PLWH) who are newly diagnosed with early syphilis. Participants will be randomized in a 1:1 ratio to receive single-dose benzathine penicillin G (BPG) (2.4 MU intramuscularly once) plus doxycycline (100 mg orally twice daily for 7 days) or single-dose BPG. The primary outcome is serologic response, defined as a decline of rapid plasma reagin (RPR) titer by 4-fold or greater, at week 24 and week 48; and the secondary outcomes include microbiologic response of syphilis and bacterial sexually transmitted infections (STIs) assessed by nucleic-acid amplification test (NAAT) at week 4.

Conditions

Early Syphilis, Latent, Serological Relapse After Treatment

Keywords

syphilis; rapid plasma reagin

Outcome Measures

Primary Outcomes (1)

• Serologic response

  Either a 4-fold or greater decline in RPR titer compared to baseline or being RPR-nonreactive

  Weeks 24 and week 48

Secondary Outcomes (4)

• Microbiologic response of syphilis

  Week 4

• Microbiologic response of bacterial STIs

  Week 4

• Safety of study treatment

  Week 4

• Adherence evaluation of tablet intake

  Week 4

Study Arms (2)

single-dose BPG plus doxycycline

ACTIVE COMPARATOR

single-dose benzathine penicillin G (2.4 MU intramuscularly once) plus doxycycline (100 mg orally twice daily for 7 days)

Drug: Benzathine Penicillin G; Drug: Doxycycline Capsule

single-dose BPG

PLACEBO COMPARATOR

single-dose benzathine penicillin G (2.4 MU intramuscularly once)

Drug: Benzathine Penicillin G

Interventions

Benzathine Penicillin G DRUG

Benzathine Penicillin G (2.4 MU intramuscularly once)

single-dose BPG; single-dose BPG plus doxycycline

Doxycycline Capsule DRUG

doxycycline (100 mg orally twice daily for 7 days)

single-dose BPG plus doxycycline

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• People living with HIV (PLWH) aged ≥18 years with early syphilis
• Confirmed by a positive RPR titer with a reactive TPPA assay

You may not qualify if:

• PWH with RPR titers of \<4
• Exposure to antibiotics with activity against T. pallidum within the preceding 4 weeks (penicillin, 3rd cephalosporin, doxycycline, macrolides)
• A known or suspected infection requiring additional treatment with an antimicrobial active against T. pallidum (penicillin, 3rd cephalosporin, doxycycline, macrolides)
• Testing positive for C. trachomatis and M. genitalium, for which doxycycline or macrolide was administered
• A history of intolerance to penicillin or doxycycline
• PLWH have already participated in this study
• Pregnancy

Sponsors & Collaborators

• National Taiwan University Hospital Hsin-Chu Branch: collaborator
• National Taiwan University Hospital: lead
• Far Eastern Memorial Hospital: collaborator
• Taipei Veterans General Hospital, Taiwan: collaborator
• Taoyuan General Hospital: collaborator
• National Cheng-Kung University Hospital: collaborator
• Chi Mei Medical Hospital: collaborator
• Kaohsiung Medical University Chung-Ho Memorial Hospital: collaborator
• Kaohsiung Veterans General Hospital.: collaborator

Study Sites (9)

National Taiwan University Hospital Hsin-Chu Branch

Hsinchu, Taiwan, 110, Taiwan

RECRUITING

Far Eastern Memorial Hospital

Taipei, Taiwan, 110, Taiwan

RECRUITING

National Taiwan University Hospital

Taipei, Taiwan, 110, Taiwan

RECRUITING

Taipei Vetetrans General Hospital

Taipei, Taiwan, 110, Taiwan

RECRUITING

Taoyuan General Hospital

Taoyuan District, Taiwan, 110, Taiwan

RECRUITING

Kaohsiung Medical University Chung-Ho Memorial Hospital

Kaohsiung City, Taiwan

RECRUITING

Kaohsiung Veterans General Hospital

Kaohsiung City, Taiwan

RECRUITING

Chi Mei Medical Hospital

Tainan, Taiwan

RECRUITING

National Cheng-Kung University Hospital

Tainan, Taiwan

RECRUITING

MeSH Terms

Conditions

Syphilis

Interventions

Penicillin G; Doxycycline

Condition Hierarchy (Ancestors)

Treponemal Infections; Spirochaetales 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

Intervention Hierarchy (Ancestors)

Penicillins; beta-Lactams; Lactams; Amides; Organic Chemicals; Sulfur Compounds; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Heterocyclic Compounds; Tetracyclines; Naphthacenes; Polycyclic Aromatic Hydrocarbons; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons; Polycyclic Compounds

Central Study Contacts

Kuan-Yin Lin, MD

CONTACT

+886-975607715; kuanyin0828@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: October 1, 2023
• First Posted: October 5, 2023
• Study Start: January 1, 2024
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2028
• Last Updated: November 18, 2025

Record last verified: 2025-10

Data Sharing

• IPD Sharing: Will not share

Locations

TW (9)