Efficacy and Safety of Single Oral Dosing of Secnidazole for Trichomoniasis in Women: Results of a Phase 3, Randomized, Double-Blind, Placebo-Controlled, Delayed-Treatment Study

Abstract

Background: Trichomonas vaginalis is the most prevalent nonviral sexually transmitted infection. We evaluated the efficacy and safety of secnidazole vs placebo in women with trichomoniasis.

Methods: Women with trichomoniasis, confirmed by a positive T. vaginalis culture, were randomized to single-dose oral secnidazole 2 g or placebo. The primary endpoint was microbiological test of cure (TOC) by culture 6-12 days after dosing. At the TOC visit, participants were given the opposite treatment. They were followed for resolution of infection afterward and offered treatment at subsequent visits, if needed. Fifty patients per group (N = 100) provided approximately 95% power to detect a statistically significant difference between treatment groups.

Results: Between April 2019 and March 2020, 147 women enrolled at 10 sites in the United States. The modified intention-to-treat (mITT) population included 131 randomized patients (secnidazole, n = 64; placebo, n = 67). Cure rates were significantly higher in the secnidazole vs placebo group for the mITT population (92.2% [95% confidence interval {CI}: 82.7%-97.4%] vs 1.5% [95% CI: .0%-8.0%]) and for the per-protocol population (94.9% [95% CI: 85.9%-98.9%] vs 1.7% [95% CI: .0%-8.9%]). Cure rates were 100% (4/4) in women with human immunodeficiency virus (HIV) and 95.2% (20/21) in women with bacterial vaginosis (BV). Secnidazole was generally well tolerated. The most frequently reported treatment-emergent adverse events (TEAEs) were vulvovaginal candidiasis and nausea (each 2.7%). No serious TEAEs were observed.

Conclusions: A single oral 2 g dose of secnidazole was associated with significantly higher microbiological cure rates vs placebo, supporting a role for secnidazole in treating women with trichomoniasis, including those with HIV and/or BV.

Clinical trials registration: NCT03935217.

Keywords: Trichomonas vaginalis; secnidazole; trichomoniasis; women.

Figure 1.

Modified intention-to-treat population and reasons for exclusion. ^aPatients could have multiple reasons for exclusion. ^bChlamydia trachomatis/Neisseria gonorrhoeae by nucleic acid amplification test. Abbreviations: BL, baseline; mITT, modified intention-to-treat; STI, sexually transmitted infection; TV, Trichomonas vaginalis.

Figure 2.

Per-protocol population and reasons for exclusion. ^aChlamydia trachomatis/Neisseria gonorrhoeae by nucleic acid amplification test. ^bPatient did not abstain from sexual intercourse during the study. ^cPatients could have multiple reasons for exclusion. Abbreviations: BL, baseline; PP, per protocol; STI, sexually transmitted infection; TOC, test of cure; TV, Trichomonas vaginalis.