A novel vaginal pH regulator: results from the phase 3 AMPOWER contraception clinical trial

Objective The objective was to evaluate the contraceptive effectiveness, safety, and acceptability of a novel vaginal pH regulator over seven cycles of use. Study design A single-arm, open-label, phase 3 study was conducted across 112 sites in the United States in sexually active 18–35-year-old women at risk of pregnancy. Women administered the study treatment ≤1 h before each episode of intercourse. Women recorded use of study drug, coital information, and any symptoms experienced in electronic diaries. The primary outcome was the seven-cycle cumulative pregnancy rate as calculated using the Kaplan–Meier methodology; secondary outcomes included safety. Overall satisfaction was assessed via written questionnaires. Results A total of 1384 women were enrolled in the study from July 2017 to November 2018. Mean age was 27.7 ± 4.4 years; most women were white (69.0%). The seven-cycle cumulative pregnancy percentage was 13.7% [95% confidence interval (CI): 10.0%–17.5%], meeting the prespecified primary endpoint of having the upper bound 95% CI ≤21%. Most common adverse events (AEs) occurring in ≥2% of women were vulvovaginal burning sensation, vulvovaginal pruritus, urinary tract infection, vulvovaginal pain, mycotic infection, bacterial vaginosis, and nasopharyngitis. Of 1330 women who used the study drug at least once, fewer than 2% of women discontinued due to any AEs, and <1% of women discontinued due to genitourinary symptoms. Overall, >80% of women reported being “very satisfied” or “satisfied” with study treatment. Conclusions In this phase 3 study, the novel vaginal pH regulator demonstrated 86.3% contraceptive effectiveness, was safe and well tolerated, and was highly acceptable. Implications This novel vaginal pH regulator is a safe, nonhormonal, woman-controlled method of contraception that expands women's options.