Therapeutic hypogonadism induced by a delayed-release preparation of microcapsules of D-Trp-6-luteinizing hormone-releasing hormone: a preliminary study in eight women with endometriosis.

Eight menstrually cycling women with proven endometriosis were treated with a delayed-release preparation of the superactive agonist D-Trp-6-LH-RH in biodegradable microcapsules, administered intramuscularly at intervals of 16 to 36 days for a period of 3 to 5 months. After the first injection which caused a transient stimulatory response, a sustained hypogonadal state, characterized by an estradiol (E2) level less than 50 pg/mL, was induced in all patients by day +14.7 (range 7.19). Subsequent injections caused no more stimulation, but a continuous decrease in E2 levels was observed. In all patients, E2 levels fell to zero after the second or third injection. Gonadotropins remained in the normal range throughout the course of treatment. Hot flashes and severe dyspareunia (related to vaginal dryness) were the main side effects. Resumption of normal pituitary-ovarian activity was documented in all patients after the last injection; the end of the hypogonadal state, ovulation and menses, occurred on days 41 (range 32-59), 58 (range 51-64) and 70 (range 65-76), respectively. All patients showed a clinical improvement. Our results demonstrate that a long-lasting, reversible hypogonadism can be induced in cyclic women by intramuscular injections of D-Trp-6-LH-RH microcapsules at monthly intervals. This simple and convenient treatment should be useful in treating endometriosis and other conditions.