A phase II study of insulin-like growth factor receptor inhibition with nordihydroguaiaretic acid in men with non-metastatic hormone-sensitive prostate cancer.

Insulin-like growth factor (IGF)-mediated signaling is a newly recognized clinical target in prostate cancer, and it is hypothesized that blockade of the IGF receptor (IGF1R) will impair downstream signaling and slow tumor growth. In this study the efficacy of nordihydroguaiaretic acid (NDGA), a small molecule inhibitor of the IGF-1R, was prospectively evaluated in patients with non-metastatic hormone-sensitive prostate cancer (HSPC). Eligible patients had non-metastatic HSPC with a rising prostate-specific antigen (PSA) and a normal testosterone level.