Treatment of metastatic prostate carcinoma with the depot LRH analog Zoladex.

A long-acting LRH agonist (ICI 118630, Zoladex) was given by monthly subcutaneous injection to 25 patients with previously untreated symptomatic advanced prostatic carcinoma. The medication was well tolerated with the only side effect being hot flushes in 15 patients. Subjective improvement occurred in 22 patients, and disease remission or stabilization judged by objective criteria was seen in 21 and 18 patients from the total group at 3 and 6 months of treatment, respectively. Twelve of 18 patients followed for 1 year were still in objective remission/stabilization. Prostate volume measured by ultrasound decreased by a mean value of 75% and urine flow increased significantly. There were significant falls in serum testosterone and gonadotrophin levels and significant although lesser reductions in serum androstenedione and dehydroepiandrosterone. These changes were accompanied by significant reductions in serum acid and alkaline phosphatase and a rise in serum osteocalcin. Four patients (16%) experienced an initial tumor flare. Although only a small number of patients were studied, Zoladex appeared to be a well-tolerated agent for treatment of prostatic carcinoma, with an initial clinical response similar to that seen with standard endocrine therapy.