Prospective trial of the herbal supplement PC-SPES in patients with progressive prostate cancer

Purpose: PC-SPES is an herbal supplement for which there are anecdotal repo rts of anti-prostate cancer activity. This phase II study was undertaken to assess the efficacy and toxicity of PC-SPES in prostate cancer patients. Patients and Methods: Thirty-three patients with androgen-dependent prostat e cancer (ADPCa) and 37 patients with androgen-independent prostate cancer (AIPCa) were treated with PC-SPES at a dose of nine capsules daily. Clinica l outcome was assessed with serial serum prostate-specific androgen (PSA) l evel measurement and imaging studies. Results: One hundred percent of ADPCa patients experienced a PSA decline of greater than or equal to 80%, with a median duration of 57+ weeks. No pati ent has developed PSA progression. Thirty-one patients (97%) had declines o f testosterone to the anorchid range. Two ADPCa patients had positive bone scans; both improved. One patient with a bladder mass measurable on compute d tomography scan experienced disappearance of this mass. Nineteen (54%) of 35 AIPCa patients had a PSA decline of greater than or equal to 50%, inclu ding eight (50%) of 16 patients who had received prior ketoconazole therapy . Median time to PSA progression was 16 weeks (range, 2 to 69+ weeks). Of 2 5 patients with positive bone scans, two had improvement, seven had stable disease, 11 had progressive disease, and five did not have ct repeat bone s can because of PSA progression. Severe toxicities included thromboembolic e vents (n = 3) and allergic reactions (n = 3), Other frequent toxicities inc luded gynecomastia/gynecodynia, leg cramps, and grade 1 or 2 diarrhea. Conclusion: PC-SPES seems to have activity in the treatment of both ADPCa a nd AIPCa and has acceptable toxicity. Further study is required to determin e whether its effects exceed those expected with estrogen therapy. (C) 2000 by American Society of Clinical Oncology.