Evaluation of Antimicrobial Prophylaxis to Prevent Syphilis in Pregnancy in Patients at Risk in Rio de Janeiro, Brazil

NCT07189208 | Recruiting Phase 2 DMC

• 2 other identifiers: 24-001337R01AI187414
• Study Type: interventional
• Target: 500
• Locations: 1 country
• Sites: 4

Brief Summary

The goal of this clinical trial is to learn if benzathine penicillin works to prevent maternal syphilis. It will also learn about the safety of benzathine penicillin. The main questions it aims to answer are:

• Does benzathine penicillin lower the rate of syphilis in pregnancy?
• What medical problems do participants have when taking benzathine penicillin? Researchers will compare benzathine penicillin to routine care to see if benzathine penicillin works to prevent syphilis. Participants will:
• Take benzathine penicillin or receive routine care during the third trimester of pregnancy
• Visit the clinic once a month for injections and tests
• Report any reactions to benzathine penicillin to the study team

Conditions

Congenital Syphilis

Keywords

congenital syphilis

Outcome Measures

Primary Outcomes (1)

• Number of participants with absence of maternal syphilis infection

  Negative POC treponemal test and VDRL test following entry into the study and at the time of labor and delivery confirming absence of maternal syphilis infection. A participant developing a positive serologic result after study entry will have reached a study endpoint and will be followed off study.

  Labor and delivery

Secondary Outcomes (19)

• Number of participants who agree to the intervention and continue on the regimen after the first visit

  First study visit through 28 days after delivery

• Degree of pain at the injection site from 0 to 10 according to the Numeric Ranking Scale

  First study visit through 28 days after delivery

• Number of participants with any cardiovascular adverse event following injection of Benzathine Penicillin G

  First study visit to labor and delivery

• Number of participants with any pregnancy complications

  Delivery through 4 weeks after delivery

• Number of participants with any dermatologic adverse event following injection of Benzathine Penicillin G

  First study visit to labor and delivery

Study Arms (2)

Counseling and intensified testing and, if negative, Benzathine Penicillin G

EXPERIMENTAL

Counseling about prevention of STIs at each pre-natal visit. Treponemal and non-treponemal tests every four weeks beginning at the 28th week of pregnancy and at delivery. If negative, IM injection of 2.4 million units of Benzathine Penicillin G. If positive, syphilis treatment based on the guidelines of the Brazilian Ministry of Health.

Drug: Benzathine penicillin 2.4 million units; Behavioral: Counseling and intensified testing.

Counseling and intensified testing without using Benzathine Penicillin G

ACTIVE COMPARATOR

Counseling about prevention of STIs at each pre-natal visit. Treponemal and non-treponemal tests every four weeks beginning at the 28th week of pregnancy and at delivery. If positive, syphilis treatment based on the guidelines of the Brazilian Ministry of Health.

Behavioral: Counseling and intensified testing.

Interventions

Benzathine penicillin 2.4 million units DRUG

IM injection of BPG

Counseling and intensified testing and, if negative, Benzathine Penicillin G

Counseling and intensified testing. BEHAVIORAL

Brazilian Ministry of Health guidelines for the prevention and diagnosis of maternal syphilis consist of counseling about STI prevention and syphilis testing at the first pre-natal consultation, at a subsequent consultation during or after 28 weeks of pregnancy, at delivery, and in case of abortion or stillbirth. In this study, intensified testing refers to treponemal and non-treponemal tests once every four weeks beginning as of the 28th week of pregnancy.

Counseling and intensified testing and, if negative, Benzathine Penicillin G; Counseling and intensified testing without using Benzathine Penicillin G

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Uncomplicated, viable pregnancy
• Elevated risk for syphilis acquisition (one or more of the following):
• Prior history of STIs last 3 years
• HIV infection
• Age \< 21 years
• In a sexual partnership of \< 3 mo., or \> 3 sexual partners in the last 6 mo.
• Late initiation of prenatal care (\> 14 weeks of pregnancy)
• Residence in area where syphilis prevalence is 10% or higher.
• Ability to provide written informed consent
• No allergy to penicillin
• Prenatal care at one of the sites participating in the study
• Ongoing sexual activity during study period.
• Negative rapid treponemal test at baseline.

You may not qualify if:

• Non-viable pregnancy
• Very high risk pregnancy
• Inability to provide written informed consent
• Allergy to penicillin
• Positive rapid treponemal test at baseline
• Lack of sexual activity during study period.
• Any persisting coagulation disorder that would contraindicate IM injections.

Sponsors & Collaborators

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

Study Sites (4)

Centro de Referencia e Atenção Especializada a Saúde da Mulher (CRAESM)

Duque de Caxias, Rio de Janeiro, Brazil

NOT YET RECRUITING

Policlínica Hospital Municipal Duque de Caxias

Duque de Caxias, Rio de Janeiro, Brazil

RECRUITING

Unidade Básica de Saúde José de Freitas

Duque de Caxias, Rio de Janeiro, Brazil

NOT YET RECRUITING

Hospital Federal dos Servidores do Estado

Rio de Janeiro, Rio de Janeiro, Brazil

RECRUITING

MeSH Terms

Conditions

Syphilis, Congenital

Interventions

Counseling

Condition Hierarchy (Ancestors)

Syphilis; Treponemal Infections; Spirochaetales Infections; Gram-Negative Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Infections; Infant, Newborn, Diseases; Congenital, Hereditary, and Neonatal Diseases and Abnormalities

Intervention Hierarchy (Ancestors)

Mental Health Services; Behavioral Disciplines and Activities; Community Health Services; Health Services; Health Care Facilities Workforce and Services

Central Study Contacts

Karin Nielsen, MD

CONTACT

310-825-5235; knielsen@mednet.ucla.edu

Esaú C João, MD, PhD

CONTACT

+55 (21) 2233-0018; esaujoao@gmail.com

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor of Clinical

Study Record Dates

• First Submitted: September 8, 2025
• First Posted: September 23, 2025
• Study Start: November 1, 2025
• Primary Completion (Estimated): January 31, 2030
• Study Completion (Estimated): January 31, 2030
• Last Updated: November 18, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share

Locations

BR (4)