BACKGROUND. The Bowman-Birk inhibitor is a soybean-derived protease inhibitor that has anti-inflammatory and anticarcinogenic activities. METHODS. A Phase I trial of Bowman-Birk inhibitor concentrate (BBIC) in 19 male subjects with benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS) has been performed. RESULTS. The results of the trial indicated that there was no dose-limiting toxicity of BBIC. There was a statistically significant decrease in serum PSA levels in all BBIC-treated patients. Some BBIC-treated patients exhibited a relatively large reduction in serum PSA levels, ranging up to a 43% reduction. There was also a statistically significant decrease in serum triglyceride levels and a decrease in prostate volume in the treated patients. The scores recorded in response to a urinary symptom questionnaire indicated improved urinary activities in the BBIC-treated patients; however, the control subjects exhibited similar improvements in urinary activities during the course of the trial. CONCLUSIONS. The data obtained in this trial, particularly the data suggesting that BBIC treatment may lead to reduced serum PSA levels and reduced prostate volumes, suggest that a Phase II clinical trial of BBIC for the therapy of BPH is warranted.

Benign prostatic hyperplasia (BPH), Bowman-Birk inhibitor, Prostate specific antigen,
The Prostate
Department of Urology

Collette, L.A.J, Studer, U.E, Schröder, F.H, Denis, L.J, & Sylvester, R. (2001). Effects of Bowman-Birk inhibitor concentrate (BBIC) in patients with benign prostatic hyperplasia. The Prostate, 48(1), 16–28. doi:10.1002/pros.1077