Am J Obstet Gynecol. 2021 Mar 8:S0002-9378(21)00156-3. doi: 10.1016/j.ajog.2021.03.005. Online ahead of print.
BACKGROUND: According to the Centers for Disease Control and Prevention, rates of infection for Chlamydia trachomatis and Neisseria gonorrhea are increasing in the United States. EVO100 is an investigational antimicrobial, pH-modulating, vaginal gel with active ingredients L-lactic acid, citric acid, and potassium bitartrate that is being evaluated for the prevention of sexually transmitted infections.
OBJECTIVE: (s): The objectives of this phase 2B/3 study were to assess the efficacy and safety of EVO100 for prevention of chlamydia and gonorrhea.
STUDY DESIGN: AMPREVENCE was a double-blinded, placebo-controlled, multicenter study based in the United States conducted over approximately 16 weeks in women age 18-45 years who were at risk of urogenital chlamydia and gonorrhea infection. Enrolled women had been diagnosed and treated for chlamydia or gonorrhea ≤16 weeks prior to enrollment. Women received either EVO100 or placebo vaginal gel and were instructed to apply the study drug immediately prior or up to 1 hour prior to each act of vaginal sexual intercourse. The primary and secondary endpoints were the prevention of urogenital chlamydia and gonorrhea, respectively. Exploratory outcomes include women's overall satisfaction with EVO100.
RESULTS: In total, 860 women were randomized 1:1 to receive EVO100 (n=426) or placebo (n=434), and 764 women (EVO100: n=376; placebo: n=388) documented using the study drug at least once. Baseline characteristics were similar between treatment arms. Overall, women had a mean age of 27.7 years (standard deviation [SD] 6.9) and body mass index of 28.9 kg/m2 (SD 8.0). Most women were of White (54.3% [467/860]) or African American (41.6% [358/860]) race and of non-Hispanic/Latina ethnicity (67.1% [577/860]). The chlamydia infection rate in EVO100 users was 4.8% (14/289) compared to 9.7% (28/290) among placebo users (P=0.0256), representing a relative risk reduction of 50%. For gonorrhea, the infection rate was 0.7% (2/280) in the EVO100 arm compared to 3.2% (9/277) in the placebo arm (P=0.0316), a relative risk reduction of 78%. Increased efficacy was observed with increased adherence, and chlamydia infection rates were significantly reduced with increased adherence in the EVO100 group compared to placebo. Across both arms, there were similar rates of all-cause adverse events (EVO100: 21.3% [80/376]; placebo: 20.4% [79/388]) and treatment-related adverse events (EVO100: 7.2% [27/376]; placebo: 7.5% [29/388]). The most common adverse events in the EVO100 arm were vulvovaginal candidiasis (5.1% [19/376]), vaginal discharge (3.2% [12/376]), and urinary tract infection (3.2% [12/376]); and in the placebo arm, bacterial vaginosis (4.6% [18/388]), urinary tract infection (2.6% [10/388]), and vaginal discharge (2.6% [10/388]). Few women discontinued due to adverse events in either arm (EVO100: 1.1% [4/376]; placebo: 1.5% [6/388]). No treatment-related serious adverse events were reported. A majority (88%) of EVO100 users were satisfied or very satisfied with EVO100 after 16 weeks of use.
CONCLUSION: (s): EVO100 significantly reduced the risk of chlamydia and gonorrhea infections in women at high risk of CT/GC infection and was well tolerated, with observed adverse events consistent with its known safety profile.