Studies of antiprostatic agents in the baboon

Flutamide and other antiandrogens in the treatment of advanced prostatic carcinoma

The various clinical trials suggest that the qualitative and quantitative responses of patients with Stage D prostatic carcinoma to antiandrogens are similar to those achieved with conventional endocrine therapy. These antiandrogens appear generally safe and many avoid the increased risks of cardiovascular or thromboembolic complications seen with estrogen therapy. Further, flutamide appears to have a lesser adverse effect on libido and sexual potency than do alternative therapies. Antiandrogens offer an alternative mode of therapy for previously untreated patients with advanced prostatic cancer but have produced no convincing benefits in hormonally refractory patients.

Treatment of advanced prostatic carcinoma with estramustine phosphate (Estracyt)

Estramustine phosphate (Estracyt) was used in the treatment of 154 patients with carcinoma of the prostate in stage IV. Sixty-three patients were given Estracyt from the outset (primary treatment group) and 91 had previously received some other endocrine therapy (secondary treatment group). All of the patients were observed for more than one year. The drug was given intravenously and/or orally. Objective remissions occurred in 46 (73.0%) of the 63 patients in the primary treatment group and subjective remissions in all the objective responders and in 12 additional patients (92.0%). The corresponding figures for the secondary treatment group were 28 (30.7%) and 52 (57.1%) of 91. The side-effects were negligible, and the drug was well tolerated. No cumulative toxic effect was observed in patients who had been receiving the treatment for more than five years. In our opinion the compound is valuable in the treatment of advanced prostatic carcinoma (stage IV).

Prostatic cancer and SCH-13521: II. Histological alterations and the pituitary gonadal axis

We herein report on the results of treatment of 13 men with stage D prostatic carcinoma with a non-steroidal compound, SCH-13521 (flutamide). The dosage of the drug was 750 mg. in 3 divided doses daily and treatment extended for 2 to 20 months. Two patients failed to respond in any fashion, 7 had objective evidence of response and the others had varying degrees of subjective response. Plasma testosterone was never suppressed and sexual potency was not altered by the drug. Gynecomastia occurred in several patients, 1 patient had intractable vomiting and 2 had thromboembolic disease. In tissue biopsies after therapy, cytotoxic changes in some acinar cells were noted but healthy-appearing neoplastic cells were always abundant. These observations suggest the pre-treatment existence of autonomous cells that no conventional hormonal manipulation will succeed in destorying. However, the palliation that flutamide seems to afford makes it important to conduct an appropriately designed study that will compare it in a suitable fashion to the effectiveness of diethylstilbestrol.