In a study of 70 patients, 37 with androgen-dependent (AD) disease and 33 with AI disease, the AD cohort was treated with PC-SPES only after an initial treatment with prostatectomy,radiation,cryotherapy, and/or hormonal therapy. Median duration of PSA response was greater than 57 weeks. All patients in the AD cohort had PSA declines within a range of 80% to 100%, and two patients with bone metastases showed improvement on radiographic analysis. Within the AI cohort, 54% (19 of 35) had a PSA decrease of greater than 50%, with median time to nadir of 10 weeks and a median duration of 18 weeks. Eight of the 16 patients who had received ketoconazole therapy prior to PC-SPES also obtained a decrease of greater than 50% in their PSA values. Testosterone levels within the AD group decreased to castrate levels (<50 ng/mL) in 94% of patients (31 of 33), and libido (25 of 25) and potency (15 of 15) were lost in all patients who entered the study. Side effects were hot flashes, gynecomastia/gynecodynia, and thromboembolic effects in 3 of 70 patients. Although the results of this trial were promising for the treatment of both AI and AD prostate cancer, it is not possible to assess what was responsible for these effects. This trial used PC-SPES from one single lot, but the published study does not indicate the lot number. The research was completed before 2000. No attempt was made to assess the possible contamination of the product. Reviewed in [3,5]
A prospective clinical series assessed the ability of PC-SPES to lower serum PSA levels in 33 prostate cancer patients. The patients had either refused conventional therapy or had failed previous cryosurgery,radiation therapy, and/or hormonal therapy. No overt signs of disease progression were found in any of the patients. At 2 months, PSA levels had decreased by a mean of 52% in 27 of the 31 patients and had increased in two patients. Of the five patients who had hormone-refractory disease, all had decreased serum PSA levels. Reviewed in [3,6]
In a continuation of the previous study, a total of 69 patients with either AI or AD disease were separated into three study groups. Group one (43 patients) had undergone previous therapy, including hormonal; group two (22 patients) developed AI after treatment; and group three (four patients) had not undergone previous therapy. The study assessed PC-SPES activity in suppressing PSA levels. Patients were given three capsules of PC-SPES 3 times per day. PSA levels and side effects were observed for 24 months.
In group one, 82% of patients (32 of 39) had a decrease in PSA levels, with 20 patients having a decrease of greater than 50% at 2 months' follow-up; the decrease lasted for 24 months in two patients. In group two (AI patients), 90% (19 of 21) had a decrease in PSA at their 2-month follow-up, with 66% (14 of 21) having a decrease of greater than 50% in PSA levels. At 24 months, two patients had a decrease of 20% to 50% in pretreatment PSA levels. In group three, 50% (2 of 4) had a decrease of greater than 50% in PSA levels at 2 months, and the remaining two patients had an increase at 2 and 6 months. Eighty-two percent of study patients had a decreased PSA level after 2 months of therapy. Side effects included nipple tenderness (42%), gynecomastia (8%), hot flashes, and deep venous thrombosis. In both Germany and the United Kingdom, PC-SPES-like formulations have been studied. A phase I trial of PC-Spes2 in the United Kingdom encountered tolerability problems due to diarrhea.
- Oh WK, Kantoff PW, Weinberg V, et al.: Prospective, multicenter, randomized phase II trial of the herbal supplement, PC-SPES, and diethylstilbestrol in patients with androgen-independent prostate cancer. J Clin Oncol 22 (18): 3705-12, 2004.
- Oh WK, George DJ, Hackmann K, et al.: Activity of the herbal combination, PC-SPES, in the treatment of patients with androgen-independent prostate cancer. Urology 57 (1): 122-6, 2001.
- Pirani JF: The effects of phytotherapeutic agents on prostate cancer: an overview of recent clinical trials of PC SPES. Urology 58 (2 Suppl 1): 36-8, 2001.
- Pfeifer BL, Pirani JF, Hamann SR, et al.: PC-SPES, a dietary supplement for the treatment of hormone-refractory prostate cancer. BJU Int 85 (4): 481-5, 2000.
- Small EJ, Frohlich MW, Bok R, et al.: Prospective trial of the herbal supplement PC-SPES in patients with progressive prostate cancer. J Clin Oncol 18 (21): 3595-603, 2000.
- de la Taille A, Hayek OR, Buttyan R, et al.: Effects of a phytotherapeutic agent, PC-SPES, on prostate cancer: a preliminary investigation on human cell lines and patients. BJU Int 84 (7): 845-50, 1999.
- de la Taille A, Buttyan R, Hayek O, et al.: Herbal therapy PC-SPES: in vitro effects and evaluation of its efficacy in 69 patients with prostate cancer. J Urol 164 (4): 1229-34, 2000.
- Shabbir M, Love J, Montgomery B: Phase I trial of PC-Spes2 in advanced hormone refractory prostate cancer. Oncol Rep 19 (3): 831-5, 2008.