Evofem Biosciences, Inc. recently announced results of a post hoc analysis of the registrational Phase 3 AMPOWER trial, which investigated the ability of a contraceptive gel consisting of lactic acid, citric acid, and potassium bitartrate (Phexxi; Evofem) to prevent pregnancy.
According to the AMPOWER trial data, the gel prevented 99% of pregnancies per act of intercourse, based on 101 pregnancies per 24,289 acts of intercourse with typical use by 1182 women.1 The pregnancy risk per act-of-intercourse is not in the Food & Drug Administration (FDA) -approved prescribing information as it was not statistically tested in AMPOWER.1
In AMPOWER, the gel solution demonstrated contraceptive efficacy, with a 7-cycle cumulative pregnancy rate of 13.7% (95% CI: 10.0%, 17.5%) with typical use and 6.67% with perfect use (95% CI: 4.61%, 8.73%), corresponding to an efficacy rate of 86.3% and 93.3%, respectively, in preventing pregnancy.
The FDA approved the gel in May 2020 based on data from both the AMPOWER trial and the AMP-001 trial, which provided more than 19,000 cycles of exposure in 2804 women in the US.
The gel solution works through vaginal pH modulation that results in the immobilization of spermatozoa. It works to maintain the normally low vaginal pH, even in the presence of semen. It is not a spermicide and does not contain surfactants such as nonoxynol-9. The gel is inserted vaginally—up to an hour before vaginal intercourse—and is not effective after sex.2
"Providing data showing how Phexxi performs on-demand to prevent pregnancy per act of intercourse helps women and their doctors better understand Phexxi and the value its innovation adds to the armamentarium of choice," said Saundra Pelletier, Chief Executive Officer of Evofem.1
1.Phexxi® Prevented 99% of Pregnancies Per Act of Intercourse in a Post Hoc Analysis of Phase 3 AMPOWER Clinical Trial Data. Evofem InvestorRoom. Published 2022. Accessed June 21, 2022. https://evofem.investorroom.com/2022-06-16-Phexxi-R-Prevented-99-of-Pregnancies-Per-Act-of-Intercourse-in-a-Post-Hoc-Analysis-of-Phase-3-AMPOWER-Clinical-Trial-Data
2. Planned Parenthood. Plannedparenthood.org. Published 2022. Accessed June 21, 2022. https://www.plannedparenthood.org/learn/birth-control/spermicide/phexxi