Monthly penicillin to prevent syphilis during pregnancy

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

This trial will test whether monthly benzathine penicillin injections plus counseling in the third trimester can prevent syphilis in pregnant people at higher risk.

Quick facts

• Phase: Phase 2
• Study type: Interventional
• Enrollment: 500 (estimated)
• Ages: 18 Years to 45 Years
• Sex: Female
• Sponsor: University of California, Los Angeles (Academic / other)
• Locations: 4 sites (Duque de Caxias, Rio de Janeiro and 3 other locations)
• Trial ID: NCT07189208 on ClinicalTrials.gov

What this trial studies

This is a randomized, unblinded Phase 2 trial comparing monthly intramuscular benzathine penicillin G (2.4 million units) plus enhanced counseling and testing to enhanced standard of care (counseling and monthly treponemal and non-treponemal tests) beginning at 28 weeks of pregnancy. Participants who are negative for syphilis at baseline and meet prespecified risk criteria will receive monthly clinic visits for testing and injections through delivery. The primary maternal endpoint is absence of treponemal and non-treponemal evidence of syphilis at delivery, and the primary infant endpoint is absence of congenital syphilis. Safety monitoring will record adverse reactions to penicillin and any pregnancy-related complications.

Who should consider this trial

Good fit: Pregnant people with a viable pregnancy who are negative for syphilis at baseline, meet one or more elevated-risk criteria (for example recent STI history, HIV infection, age under 21, recent new partners, late prenatal care, or residence in a high-prevalence area), can consent, and can attend monthly prenatal visits at a participating site are ideal candidates.

Not a fit: People with a positive baseline syphilis test, a penicillin allergy, non-viable or very high-risk pregnancies, lack of sexual activity during the study period, or contraindications to IM injections would not be expected to benefit from this prophylaxis.

Why it matters

Potential benefit: If successful, this approach could lower maternal syphilis rates and reduce cases of congenital syphilis and related infant illness.

How similar studies have performed: Using routine monthly benzathine penicillin as prophylaxis in pregnancy is a relatively novel approach with limited prior trial data and has not been widely tested.

Eligibility criteria

Inclusion Criteria:

1. Uncomplicated, viable pregnancy
2. Elevated risk for syphilis acquisition (one or more of the following):

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

Exclusion Criteria:

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

Where this trial is running

Duque de Caxias, Rio de Janeiro and 3 other locations

• 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)

Study contacts

• Study coordinator: Karin Nielsen, MD

Conditions Congenital Syphilis; congenital syphilis