Antares Pharma, Population Council report positive Phase 2 results for novel NES/E2 contraceptive gel

Antares Pharma, Inc. (NYSE Amex: AIS) and the Population Council today announced successful results from a dose-finding Phase 2 trial for a novel contraceptive gel containing the progestin Nestorone and estradiol (NES/E2) utilizing the Antares ATD (advanced transdermal delivery) gel system. Based on this successful data, the two parties continue to expect to partner with a worldwide or regional pharmaceutical company in order to commercialize this novel contraceptive gel.

This first of its kind contraceptive gel may offer an attractive option for women. The combination of Nestorone, a highly potent and versatile synthetic progestin, and the natural estrogen estradiol, was chosen due to the potential for superior safety profiles when compared to other commonly used hormones in contraceptives. The ATD system is currently utilized in Elestrin® a marketed product for hormone replacement therapy (HRT) in postmenopausal women. The gel is easy to apply, crystal clear, fast drying and cosmetically appealing.

The trial was a dose-finding, open-label, cross-over study to evaluate the effect of NES/E2 transdermal gel on ovulation suppression in normal women of fertile age. Eighteen women participated in the trial, which took place in three sites: Los Angeles, California; Santo Domingo, Dominican Republic; and Santiago, Chile. Each woman completing the study received each of the three separate doses of the gel for 21 days, separated by a washout month in which no products were administered when they recovered normal ovulation. The primary objective of the study was to find the lowest acceptable dose of the NES/E2 gel to achieve appropriate therapeutic levels for effective contraception (ovulation suppression), as measured by progesterone levels and ultrasound evaluation of follicular development. Secondary objectives included determining the plasma profile of estradiol and the evaluation of bleeding patterns. General safety and tolerability of the NES/E2 gel, including any local skin irritation, was also assessed.

Active treatment concluded in October 2009. Safety and efficacy objectives were met and no serious adverse events or instances of skin irritation were recorded.

Régine Sitruk-Ware, executive director for research and development in the Reproductive Health program of the Population Council, said, “We have demonstrated that the transdermal gel combining Nestorone and estradiol is able to suppress ovulation at all doses tested and we determined the dose that gave the most stable levels of hormones to the subjects. Most women who participated in the study found the gel very easy to use and convenient. We believe this new formulation is likely to be a safe and effective contraceptive that offers a new option for women who may be unable to use alternative forms of contraception.”

"The advantage of using transdermal delivery has been seen with HRT products where recent studies have shown a reduced side effects profile when compared to orally administered products. The ATD system offers a patient friendly, fast drying and cosmetically appealing gel product which can be easily applied daily. This product may offer an excellent opportunity to provide the most safe and effective contraception through an innovative drug delivery system in a large and growing global market segment,” said Dario N. Carrara Ph.D., Antares Senior Vice President and Managing Director and the inventor of the ATD system.

The National Survey of Family Growth has revealed that 31 percent of women discontinue use of reversible contraceptives for method-related reasons within six months of starting use, and 44 percent do so within 12 months. The novel NES/E2 transdermal gel offers a potentially attractive contraceptive option, in that both the formulation and the active compounds are designed to reduce the adverse events profile observed with current contraceptive methods and therefore could result in higher continuation rates by users. According to Business Insights (2007) the contraceptive market is projected to reach $7.5 billion by 2011.

Under the terms of a joint development agreement, Antares is responsible for research and development activities as they relate to ATD formulation and manufacturing, using the Population Council’s patented and other proprietary information covering the compound. The Population Council is responsible for research on Nestorone and clinical trial design development and management.