Suramin treatment in hormone- and chemotherapy-refractory prostate cancer

Objectives. Suramin, a polysulfonated naphtylurea with anti-growth factor a ctivity, was used in the treatment of metastatic, hormone- and chemotherapy -refractory prostate cancer. Recent studies have proved the effect of suram in on prostate cancer. Methods, Between March 1990 and January 1994, 27 patients with metastatic p rostate cancer were enrolled in this study. Treatment regimen consisted of a loading phase, allowing patients to reach suramin serum levels between 18 0 and 250 mu g/mL using a suramin dose of 1.4 g/m(2) at 3-day intervals. Co nstant suramin serum levels were maintained by a 0.5 to 1-g/m(2) dose every 7 to 10 days. Because previous studies showed suramin to have serious toxi city, compromised organ status was excluded by repeated examinations. Results. Six patients did not complete the suramin loading phase because of side effects and were removed from the study. With an average cumulative s uramin dose of 14.2 g, 33% of the assessable patients (7 of 21) experienced a more than 50% reduction of prostate-specific antigen (PSA) and/or alkali ne phosphatase (AP) serum levels. Mean survival in these suramin-responsive patients was 495 days. Two of these patients experienced a remarkable redu ction of metastases in bone scan examinations. Another 48% of the patients (10 of 21) had essentially unchanged AP and PSA serum levels during suramin treatment, indicating stable disease. Mean survival of these patients was 341 days. In 4 patients undergoing suramin treatment, continuous clinical p rogression of the disease was observed (mean survival 79 days). Toxicity wa s less or comparable to prior reported studies; the most common side effect s were polyneuropathy, allergic skin rash, and vortex keratopathy. Conclusions, Suramin has limited, but significant, efficacy even in chemoth erapy- and hormone-refractory prostate cancer, without serious toxicity. (C ) 1999, Elsevier Science Inc. All rights reserved.