Disclosures: The authors report no relevant financial disclosures.
March 14, 2021
2 min read

Twice-daily oral cefixime nearly 90% successful in treating early syphilis

Disclosures: The authors report no relevant financial disclosures.
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Cefixime, administered orally, twice daily for 10 days, was nearly 90% successful in treating early syphilis, according to a study published in Clinical Infectious Diseases.

Jeffrey Klausner, MD, MPH, clinical professor of preventive medicine at the University of Southern California Keck School of Medicine, and colleagues noted that the CDC and WHO both recommend injectable benzathine penicillin G for syphilis — noting that it is the only recommended treatment for syphilis in pregnancy— and that doxycycline, tetracycline and ceftriaxone are recommended as alternatives, with limitations.

syphilis infographic
Source: Stafylis C, et al. Clin Infect Dis. 202;doi:10.1093/cid/ciab187.

“While the recommended treatment for early syphilis is injectable penicillin, in many places, penicillin is not available. In the United States, injectable penicillin can cost $350 or more for a single shot, and in many parts of the world, while lower cost, it just is not available due to very limited manufacturing,” Klausner told Healio. “Syphilis is on the increase. The U.S. had the highest rates of congenital syphilis in more than 25 years. There is an urgent public health need for more treatments for syphilis. Treatments that are safe, inexpensive and readily available are the most important.”

Klausner and colleagues performed a randomized, open-label, noncomparative pilot study in men and women diagnosed with primary, secondary or early latent syphilis at five primary care HIV community clinics of the AIDS Healthcare Foundation in California, enrolling patients between September 2018 and January 2020. Participants were randomly assigned 1:1 to receive either benzathine penicillin G 2.4 MIU intramuscularly once or cefixime 400 mg by mouth twice a day for 10 days.

Jeffrey Klausner

“Cefixime is an FDA-approved orally administered third-generation cephalosporin,” Klausner and colleagues wrote, and “cephalosporins could be good candidates for evaluation” to treat early syphilis.

According to the study, 58 participants were enrolled 27 in the cefixime arm and 31 in the penicillin arm. All randomly assigned participants were included in the intent-to-treat population, whereas the per-protocol population included 15 participants randomly assigned to the cefixime arm and 15 randomly assigned to the penicillin arm.

In the per-protocol population analysis, treatment response at 3 or 6 months was achieved by 93% (95% CI, 81%-100%) of participants in the penicillin arm and 87% (95% CI, 69%-100%) in the cefixime arm, whereas in the intent-to-treat analysis, treatment response was achieved by 81% (95% CI, 67%-95%) in the penicillin arm and 56% (95% CI, 37%-74%) in the cefixime arm.

According to the study, three cases of serological failure were recorded — two among

participants in the cefixime arm and one in a participant in the penicillin arm. Additionally, of the 27 participants who received cefixime, one adverse event was recorded. The study detailed that the participant reported a mild skin rash within 4 hours of receiving the first dose of cefixime and that the participant was advised to stop treatment and was reevaluated at the clinic.

“The take-home message is that cefixime is promising, but more research and larger studies are needed,” Klausner said. “To address the crisis in antibiotic development, we can and should work to repurpose older, safe medications as new treatments.”

Klausner said researchers have begun work on a larger randomized controlled trial in U.S. and Peru to assess if cefixime works as well as injectable penicillin and they have expanded the study population to include women.