ST LOUIS (MD Consult) - On August 13, 2010, Watson Pharmaceuticals announced that the US Food and Drug Administration (FDA) has approved ella (ulipristal acetate), an oral prescription-only emergency contraceptive. The product prevents pregnancy when taken within 120 hours (5 days) after contraceptive failure or unprotected intercourse (UPI). It is not intended for routine use.

ella is a progesterone agonist/antagonist. It is believed that the drug's mechanism of action is to bring about an inhibition or delay in ovulation. According to Watson, currently available over-the-counter levonorgestrel-based emergency contraceptives are indicated for use within 72 hours of UPI or contraceptive failure, and their effectiveness in preventing pregnancy decreases just before the onset of ovulation.

The safety and efficacy of ella were demonstrated in 2 phase 3 clinical trials. One study was a prospective, multicenter, open-label, single-arm trial conducted in the United States; the other was a randomized, multicenter, single-blind comparator-controlled trial conducted in the United States, United Kingdom, and Ireland. Among women in the trials who received ella within 72 hours of UPI, the overall pregnancy rate was 1.9%, significantly lower than the anticipated pregnancy rate (5.6%). Among women who received ella 48 to 120 hours post-UPI, the overall pregnancy rate was 2.2%, significantly lower than the expected pregnancy rate (5.5%).

Among the more than 2,600 women who received ella 30 mg in clinical trials, the most commonly reported adverse events in the open-label and single-blind studies, respectively, were mild to moderate headache (18%/19%), nausea (12%/13%), abdominal and upper abdominal pain (15%/8%), dysmenorrhea (7%/13%), fatigue (6%/6%), and dizziness (5%/5%). According to Watson, this safety profile is similar to that of other available oral emergency contraceptives.

ella should not be used during an existing or suspected pregnancy, and women who become pregnant or complain of lower abdominal pain after taking ella should be examined for the possibility of an ectopic pregnancy. Repeated use of ella within the same menstrual cycle is not recommended, and because a rapid return of fertility is likely after the use of ella, routine contraception should be continued or initiated as soon as possible.

ella is expected to be available in the United States at the beginning of the fourth quarter of 2010.

圣路易斯(MD Consult)——华生制药公司于2010年8月13日宣布，美国食品药品管理局(FDA)已批准ella(醋酸ulipristal，该药是用于紧急避孕的一种口服处方药)上市。女性在避孕失败或无保护性交(UPI)后120 h(5天)内使用该药可以预防妊娠。但该药不能作为常规避孕手段使用。

 

ella是一种孕酮激动剂(拮抗剂)。人们通常认为，该药的作用机制在于其可以抑制或延迟排卵。据华生公司介绍，目前市面上有售的以左炔诺孕酮为主要成分的非处方紧急避孕药通常适合在无保护性交或避孕失败后72 h内使用，而排卵进程一旦启动，这类药物的避孕性能就下降了。

 

研究者已通过两项Ⅲ期临床试验证实了ella的安全性和有效性。其中1项研究是在美国开展的前瞻性、多中心、开标签、单试验组临床试验；另1项研究是由美国、英国和爱尔兰联合开展的随机化、多中心、单盲比较对照试验。在这些试验中，如果受试女性在无保护性交后72 h内服用ella，其总妊娠率为1.9%，该数值显著低于预期妊娠率(5.6%)。对于在无保护性交后48~120 h之间服用ella的受试女性而言，其总妊娠率为2.2%，这一数值显著低于预期妊娠率(5.5%)。

在参与这两项临床试验的2,600例女性(ella的给药剂量为30mg)中，开放性和单盲研究所报告的最常见不良事件分别为轻至中度的头痛(18%/19%)、恶心(12%/13%)、腹痛和上腹痛(15%/8%)、痛经(7%/13%)、乏力(6%/6%)和头晕(5%/5%)。据华生公司介绍，该药在安全性能方面与市售的其他口服紧急避孕药类似。

 

ella不宜用于已确证或疑似妊娠的女性，如果某位女性在服用ella后出现妊娠或自诉存在下腹痛，则应该对其进行检查，以排除异位妊娠的可能性。我们不推荐在同一月经周期中重复使用ella，此外，因为女性在服用ella不久后便会迅速恢复生育能力，所以，应该尽快开始或继续进行常规避孕。

 

据预期，ella将于2010年第4季度初在美国上市。