Shares in Watson Pharmaceuticals inched up before the weekend on news that US regulators have cleared the emergency contraceptive ella, paving the way for its launch before the end of the year.

The company said on Friday that it intends to roll out ella (ulipristal acetate), originally developed by HRA Pharma, in the US during the fourth quarter of 2010 after the Food and Drug Administration issued its stamp of approval for the drug, following in the footsteps of its European counterpart which gave the all clear last year.

Ella is a progesterone agonist/antagonist emergency contraceptive that can help prevent pregnancies at various stages of the menstrual cycle, and regulators have cleared its use for up to 120 hours – five days, the amount of time sperm can survive for in the genital tract – after unprotected sex or the failure of conventional means of contraception.

Approval follows an extensive clinical trial programme showing the drug to be a safe and effective means of emergency contraception. According to Watson, the overall pregnancy rate among women given ella up to 72 hours following unprotected intercourse was 1.9%, and thereby significantly lower than the anticipated pregnancy rate of 5.6%, while among those given the drug within 48-120 hours the overall pregnancy rate was 2.2%, much lower than the expected rate of 5.5%.

The firm has high hopes that ella will help to address an unmet medical need, given that the over-the-counter levonorgestrel-based emergency contraceptives currently available can only be taken within 72 hours of unprotected sex or contraception failure and, unlike ella, their effectiveness decreases just prior to ovulation.

Furthermore, around three million unintended pregnancies occur each year, of which 48% occur in women using regular methods of birth control where a failure occurred.

“ella is an important new contraceptive option for US women, and its unique efficacy profile will give women an additional therapeutic alternative for preventing unintended pregnancy,” remarked Fred Wilkinson, Executive Vice President, Global Brands at Watson.