Ovaprene phase 3 interim data supports potential of monthly hormone-free contraceptive

Daré Bioscience has announced positive interim safety and efficacy results from its ongoing phase 3 clinical trial (NCT06127199) of Ovaprene, an investigational monthly, hormone-free intravaginal contraceptive. The contraceptive consists of a vaginal ring and a mechanical barrier that releases spermiostatic ferrous gluconate.^1,2

The trial’s independent Data Safety Monitoring Board (DSMB) conducted a planned review of the safety data and recommended that the study continue without modification.¹

Study design and regulatory outlook

The ongoing phase 3 trial is a multicenter, single-arm, open-label study that includes women aged 18 to 40 years, operating across 5 locations. The primary objective is to assess the typical-use pregnancy rate over 13 menstrual cycles using the Pearl Index, a standard measure of contraceptive effectiveness.

Phase 3 interim safety, efficacy of Ovaprene

The interim analysis included data from 339 study subjects across 1789 menstrual cycles. Key findings from the data include the following:

• Pregnancy: Approximately 9% of women enrolled in the study experienced a pregnancy. In a news release, Daré Bioscience noted this figure is consistent with expectations based on prior pre-pivotal postcoital clinical studies. A formal Pearl Index—the trial's primary end point—has not yet been calculated and will not be available until the study is complete, according to the company.
• Adverse events: No serious adverse events related to the device were identified. The most common product-related adverse event was vaginal odor, which led to discontinuation in 12% of participants—a 5% decrease from the previous interim analysis in July 2025.
• Tolerability: Prolonged use of the device was not associated with an increase in the frequency of adverse events or the emergence of new types of safety concerns.

Ovaprene data on postcoital testing

Regarding data associated with the previous pre-pivotal postcoital clinical studies, the 2024 results were published in Contraception. In the multicenter, open-label study, participants underwent a baseline postcoital test (PCT) cycle without a device to establish a sperm baseline, followed by cycles utilizing a diaphragm and the Ovaprene ring. Effectiveness was defined as achieving less than 5 progressively motile sperm per high power field (HPF) in the cervical mucus 2 to 4 hours after intercourse.²

Of the 38 enrolled participants, 23 completed the study, with results showing that Ovaprene met the definition of a successful PCT in all 49 evaluation cycles.

The baseline mean of 27.2 (±17.9) progressively motile sperm/HPF was reduced to 0.5 (±1.1) in the first Ovaprene cycle and 0.5 (±1.3) in the second Ovaprene cycle. Additionally, the contraception fit all participants who could insert, position, and remove it, according to the study authors.

Ovaprene study continuation

The study protocol originally targeted 2500 cycles of exposure and at least 250 subjects completing 13 cycles. However, based on the stable safety data observed with prolonged use, the company intends to engage with the FDA to discuss whether fewer than 250 subjects completing the full 13 cycles would be sufficient for the safety evaluation. Daré Bioscience expects to achieve the 2500 cycles of exposure required for the primary end point analysis in 2026.

References:

1. Positive interim phase 3 results highlight potential of Ovaprene, novel hormone-free contraceptive. News release. Daré Bioscience Inc. May 12, 2026. Accessed May 13, 2026. https://www.globenewswire.com/news-release/2026/05/12/3292740/30757/en/positive-interim-phase-3-results-highlight-potential-of-ovaprene-novel-hormone-free-contraceptive.html
2. Mauck C, Thurman A, Jensen JT, et al. Successful postcoital testing of Ovaprene: an investigational non-hormonal monthly vaginal contraceptive. Contraception. 2024;132:110373. Accessed May 13, 2026. https://www.sciencedirect.com/science/article/pii/S001078242400012X