ICI's ZOLADEX NDA FOR TREATMENT OF ENDOMETRIOSIS FILED

Executive Summary

ICI's ZOLADEX NDA FOR TREATMENT OF ENDOMETRIOSIS FILED on July 30, the company announced in an Aug. 1 press release. The NDA filing, containing data on over 200 women, is the second indication sought for the gonadotropin-releasing hormone (GnRH) agonist by the firm. Zoladex (goserelin acetate) has been available since January 1990 for the treatment of advanced prostate cancer. Zoladex will be the third GnRH agonist reviewed by FDA for the treatment of endometriosis. Syntex's Synarel (nafarelin acetate) was approved in February 1990 as the first new endometriosis treatment to enter the U.S. market in 14 years, since the introduction of Sterling's androgen therapy, danazol (Danocrine). Takeda-Abbott Pharmaceuticals' Lupron Depot was approved in October 1990. Data from the two studies submitted to FDA, one U.S. and one British, show that Zoladex treatment significantly reduced the number, size and location of endometrial implants, plaques, endometriomas and/or lesions in 62% of the women treated. In contrast, danazol reduced endometrial lesions in 39% of women, ICI reported in the release. FDA limited the treatment period with Synarel to six months because of a lack of safety data beyond that length of time and because the treatment was associated with a 4.3% decrease in bone mass. Similarly, treatment was limited to six months in the Zoladex studies,in which a 4-5% reduction in bone mass was recorded. ICI declared in the release that only 1% of Zoladex patients withdrew from the studies compared to 10% of patients receiving danazol. Zoladex therapy is associated with adverse events common to GnRH agonists, such as hot flashes and amenorrhea. Therapy with danazol is associated with such side effects as weight gain, acne, muscle cramps, and sometimes hair growth and voice lowering. The method and schedule of administration of Zoladex is its main distinguishing feature from Synarel, but is similar to that of Lupron Depot. Synarel is given through a twice-daily intranasal spray, whereas Zoladex is administered once each month by a physician through subcutaneous injection. The drug is contained in a solid polymer pellet which dissolves over the one-month period.