Efficacy of (D-Leu6)-des Gly-NH2 10-LHRH ethylamide against prostatic cancer.

Twenty-two patients with prostatic cancer were treated for 12 to 52 weeks with the luteinizing hormone-releasing hormone agonist, (D-Leu6)-des Gly-NH2 10-LHRH ethylamide (leuprolide). The clinical efficacy of leuprolide was evaluated at 12 weeks according to NPCP criteria. All seven patients with Stage B and C disease demonstrated a partial objective regression. The objective response rate in 12 previously untreated Stage D patients was 92% (partial regression: 5; stable disease: 6). In three relapsing Stage D patients, one demonstrated stable disease and two failed to respond to leuprolide therapy. Even though the dose of leuprolide used in this study was high, no serious side effects were observed in any patients. There was a large increase in serum FSH and LH levels during the first few days of treatment, but serum FSH and LH levels fell below the initial levels by 1 and 2 weeks, respectively. Serum testosterone fell to less than 1 ng/ml within 3 weeks, and at 12 weeks it was 7.99% of the initial level. The present study shows that chronic administration of leuprolide in high doses can safely and effectively reduce the level of serum testosterone in patients with prostatic cancer.