A phase II trial of estramustine and etoposide in hormone refractory prostate cancer: A Southwest Oncology Group trial (SWOG 9407).

BACKGROUND: The combination of oral estramustine and oral etoposide has generated response rates of 40-50% in patients with hormone refractory prostate cancer in single institution trials. This study tested this regimen in a multi-institutional setting. METHODS: Fifty-five patients were accrued over a period of 4 months between 1 March 1996 and 1 July 1996. Two patients were not analyzable and two patients were ineligible. They were given an oral regimen consisting of estramustine 15 mg/kg/day (capped at 1120 mg per day) and etoposide 50 mg/M(2)/day, days 1-21 every 28 days. Patients received a median of two cycles of therapy. RESULTS: Toxicities included 11 patients (20%) with grades 3 or 4 granulocytopenia, 5 patients (10%) with grades 3 or 4 edema, and 3 patients (6%) with a thrombotic event. There were two treatment-related deaths, one as a result of anemia and the other as a result of a myocardial infarction. Of the 32 men who received at least 2 cycles of therapy, 7 men (22%) demonstrated a partial response to this regimen as measured by prostate-specific antigen (PSA) criteria of a 50% decline from pretreatment values. CONCLUSIONS: This trial demonstrates the toxicity of estramustine delivered in high dose. It also illustrates the difficulty of conducting phase II trials in prostate cancer in the cooperative group setting where the experience and comfort level of oncologists with new agents is less than that of the physicians at the institution where the therapy was developed. As the activity of this regimen with low-dose estramustine is defined, further multi-institutional studies may be warranted.

Androgen deprivation and four courses of fixed-schedule suramin treatment in patients with newly diagnosed metastatic prostate cancer: A Southwest Oncology Group Study.

PURPOSE: To assess the feasibility of administering a combination of suramin and hydrocortisone in addition to androgen deprivation in a cooperative group setting; to assess the feasibility of treatment with multiple courses of suramin; and to assess progression-free and overall survival in patients with newly diagnosed metastatic prostate cancer who underwent such treatment. PATIENTS AND METHODS: Patients with newly diagnosed metastatic prostate cancer who had adequate hematologic, hepatic, renal, neurologic, and coagulation parameters were treated by combined androgen deprivation and suramin plus hydrocortisone. Suramin was administered on a 78-day fixed dosing schedule (one cycle), and suramin treatment cycles were repeated every 6 months for a total of four cycles. The statistical design was developed on the basis of the feasibility of administering suramin, as judged by the number of patients who developed neurotoxicity of grade 3 or higher or by treatment interruption of 4 weeks or longer due to any persistent suramin-related toxicity. RESULTS: Of the 62 patients enrolled onto the study between August 1994 and January 1997, 59 were eligible and assessable for toxicity on the first cycle. Thirty-two (54%) of 59 patients received a second cycle, 13 (22%) of 59 patients received a third cycle, and only five patients (8%) received a fourth cycle. During the first cycle, 27 patients were removed from the study: 17 because of toxicity, five because of disease progression, two who had died, and three because of other reasons. There was one therapy-related death. Grade 4 toxicities were noted in 11 and three patients during first and second courses, respectively. Neurotoxicity of grade 3 or higher was observed in nine and seven patients during the first and second cycles, respectively. Fifteen patients had treatment interruptions of 4 weeks or longer. Overall, only 54% (95% confidence interval, 41% to 67%) of the patients demonstrated acceptable limits of toxicity. CONCLUSION: Suramin plus hydrocortisone and androgen deprivation has limited applicability in the treatment of patients with newly diagnosed metastatic prostate cancer.