Comparing an oral antibiotic (cefixime) to penicillin shots for early syphilis

Clinical Trial Comparing the Effectiveness of Cefixime Versus Penicillin G for Treatment of Early Syphilis

NIH-funded research University of Southern California · NIH-11159118

This trial compares taking cefixime pills versus receiving penicillin injections to treat early syphilis in people with and without HIV.

Quick facts

Grant typeR01 grant
Study typeNIH-funded research
Funding institutionUniversity of Southern California NIH-funded
Lab location1 site (Los Angeles, UNITED STATES)
Project IDNIH-11159118 on NIH RePORTER

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.

Who could benefit from this research

Good fit: Adults with early syphilis, including people living with HIV, who can attend regular follow-up visits and take oral medication or receive injections.

Not a fit: 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.

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 performed: 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

Los Angeles, UNITED STATES

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Conditions Acquired Immune Deficiency Syndrome VirusAcquired Immunodeficiency Syndrome Virus
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.