Comparing an oral antibiotic (cefixime) to penicillin shots for early syphilis
Official title: Clinical Trial Comparing the Effectiveness of Cefixime Versus Penicillin G for Treatment of Early Syphilis
Funded at University of Southern California · NIH-11159118 · Data updated 2026-11-12
This trial compares taking cefixime pills versus receiving penicillin injections to treat early syphilis in people with and without HIV.
Quick facts
| Grant type | R01 grant |
|---|---|
| Study type | NIH-funded research |
| Funding institution | University of Southern California NIH-funded |
| Lab location | 1 site (Los Angeles, UNITED STATES) |
| Project start | July 13, 2020 |
| Project end | July 31, 2027 |
| Funding year | 2025 |
| Award (this year) | $702,115 |
| NIH project number | 4R01AI155217-06 |
| Project ID | NIH-11159118 on NIH RePORTER |
Who could benefit from this research
✓Could help
Adults with early syphilis, including people living with HIV, who can attend regular follow-up visits and take oral medication or receive injections.
✕Less likely to help
Pregnant people, those with late-stage or neurosyphilis, or anyone unable to take the study medications or attend follow-up visits may not be eligible or receive benefit.
What this research studies
If you join, you will be randomly assigned to take cefixime pills twice a day for 10 days or receive a single benzathine penicillin G injection. The study will enroll 360 people with early syphilis across nine U.S. clinical sites and includes participants with and without HIV. Doctors will monitor symptoms and blood tests (RPR titers) every three months for nine months to see whether the infection clears. The trial is open-label, so you and your care team will know which treatment you receive, and it is designed to show whether cefixime works at least as well as penicillin.
Why it matters
Potential benefit: If successful, this could offer an effective oral alternative to penicillin injections, making treatment easier to access and use for many patients.
How similar studies have gone: A prior pilot study suggested cefixime may be effective, but few large randomized trials have tested oral alternatives to penicillin for syphilis.
Where this research is happening
-
University of Southern California
Los Angeles, United States Active
Researchers
- Principal investigator: Klausner, Jeffrey David — University of Southern California
- Study coordinator: Klausner, Jeffrey David
Related research
Other NIH-funded projects on the same topics.
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Syphilis in Pregnancy: Understanding Infection in Moms and Babies
A study following pregnant women with syphilis and their babies to learn how the infection affects pregnancy and newborn health.
-
Syphilis in Pregnancy: Molecular Tests and Immune Responses in Mom and Baby
A study to understand how syphilis affects pregnancy and newborns by using molecular tests and tracking immune responses in 750 pregnant women with syphilis and their babies.
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Crowdsourced digital messaging to boost syphilis and HIV testing for women in NYC and rural Alabama
A community-driven project tests whether crowdsourced digital messages can encourage women, especially women of color and Native American women, to get syphilis, HIV, and STI tests.
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Preventing syphilis in pregnant people in Rio de Janeiro
A clinical trial in Brazil tests a pregnancy-safe antibiotic plan to stop syphilis from affecting babies.
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Cefixime vs Penicillin G for Early Syphilis in HIV and non-HIV patients
This project compares a cefixime-based treatment to standard penicillin for early syphilis in people with and without HIV.
-
Preventing congenital syphilis in pregnant people at risk in Rio de Janeiro
A clinical trial will test a treatment approach during pregnancy to reduce syphilis transmission from mother to baby for pregnant people at risk in Rio de Janeiro.
About this research
- This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
- Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
- For full project details, budget, and progress reports, visit the official NIH RePORTER page.