The purpose of this study is to determine the pharmacodynamics of leuprorelin gelatin free formulation (GF) to leuprorelin gelatin containing formulation (GC) in female subjects with uterine fibroids.

Gonadotropin-releasing hormone, also called luteinizing hormone releasing hormone, is a neuropeptide hormone released from the hypothalamus. Gonadotropin-releasing hormone binds to specific gonadotropin-releasing hormone receptors in the cell membrane of pituitary gland cells, inducing the cells to produce and release the gonadotropins: luteinizing hormone and follicle-stimulating hormone. Luteinizing hormone and follicle-stimulating hormone are released into the general circulation and stimulate the gonads to produce and release the sex steroids: testosterone and estrogen. Follicle-stimulating hormone also controls gametogenesis. Suppression of gonadotropin secretion is an effective treatment for conditions such as prostate cancer, endometriosis and central precocious puberty, because these conditions respond to manipulation of the sex steroids. Suppression of gonadotropin secretion can be achieved by administration of gonadotropin-releasing hormone agonists that, after an initial transient stimulation of gonadotropin release, reversibly desensitize pituitary gonadotropin-releasing hormone receptors. Desensitization is thought to occur by down-regulation of the numbers of gonadotropin-releasing hormone receptors and uncoupling of the receptors from the biochemical pathway that leads to gonadotropin release. Termination of gonadotropin-releasing hormone agonist administration reverses the desensitization, and gonadotropin and sex hormone levels return to normal. There are several marketed gonadotropin-releasing hormone agonists, one of which is TAP-144 (leuprorelin), an active synthetic nonapeptide gonadotropin-releasing hormone analogue. In the present study, the existing leuprorelin 1- month sustained release formulation will be compared with a new gelatin-free 1-month sustained release formulation.