P771 Clinical trial of cefixime for the treatment of early syphilis – preliminary results

Background Increasing incidence of syphilis in the United States and penicillin shortages internationally call for research on alternative treatment options. In this randomized, multisite, open-label, non-comparative clinical trial, we are evaluating the efficacy of cefixime as treatment of early syphilis. Methods Eligible participants are 18 years or older, have laboratory confirmed early syphilis (new Rapid Plasma Reagin [RPR] titer ≥1:8 or 4-fold titer rise in past 12 months), and no concomitant antibiotic use. Patients with HIV infection must have undetectable viral load in the past 12 months and CD4+ count ≥350 cells/μl. Participants were randomized to receive either 2.4M IU benzathine penicillin G intramuscularly once or cefixime 400 mg orally twice a day, for ten days. Participants return for follow-up at 3, 6, and 12 months post-treatment for laboratory testing. The main outcome is a 4-fold RPR titer decrease at 6 months post-treatment. Results To date, 27 participants (15 penicillin, 12 cefixime) are enrolled. The majority of the study population is men (26/27), Latino (15/27), and HIV-infected (25/27). Eight participants completed their 3-month follow up (4 cefixime/4 penicillin). In the cefixime arm, 3/4 participants had an equal or greater than four-fold decrease in the RPR titer, and 1/4 had a two-fold decrease. In the penicillin arm, 2/4 participants had an equal or greater than 4-fold decrease in the RPR titer, 1/4 had a two-fold decrease, and 1/4 is missing data. Conclusion Enrollment is still open and data collection ongoing. Initial results are encouraging. Disclosure No significant relationships.