Perfect-Use Pregnancy Rates With the Vaginal pH Regulator: Efficacy Results From AMPOWER [30I

Abstract

INTRODUCTION: To address women’s unmet contraceptive needs, the investigational vaginal pH regulator (VPR™) was developed as a novel, non-hormonal, woman-controlled vaginal gel. The IRB-approved, phase 3 AMPOWER study met its primary efficacy endpoint: the typical-use 7-cycle cumulative pregnancy percentage with VPR was 13.7% (95% CI 9.91%, 17.39%) (Thomas et al, ASRM 2019). Here we present perfect-use VPR efficacy results. METHODS: AMPOWER (NCT03243305) was a single-arm, open-label, confirmatory trial conducted at 112 U.S. sites. Women were instructed to administer a single prefilled applicator of study drug intravaginally before each episode of intercourse. For inclusion in the perfect-use analyses, study cycles met rigorous criteria including: 21 to 35-day cycle; no back-up or emergency contraception; 1 or more recorded act of intercourse; and correct use of VPR for every act of intercourse in that cycle, per eDiaries. To more accurately evaluate efficacy, the perfect-use analysis was repeated to remove factors that confounded efficacy assessment in ad hoc sensitivity analyses. RESULTS: AMPOWER enrolled 1,384 women; in the efficacy-evaluable population (n=1,003), the perfect-use 7-cycle cumulative pregnancy percentage was 9.99% (95% CI 7.17%, 12.81%). When including all 21 to 42-day cycles and removing subjects with incomplete washout of previous hormonal contraceptive and removing pregnancies from cycles with inconsistent eDiary reporting, the 7-cycle cumulative pregnancy percentage ranged from 6.67% (95% CI 4.61%, 8.73%) based on all evaluable cycles to 8.44% (95% CI 5.90, 10.98%) based on perfect-use cycles. CONCLUSION: Using multiple sensitivity analyses to determine perfect-use efficacy, women’s 7-cycle cumulative pregnancy percentage ranged from 6.67% to 9.99% with VPR.