Study of Itraconazole in Castrate-resistant Prostate Cancer (CRPC) Post-chemotherapy

Castration-resistant prostate cancer (CRPC) is also known as "androgen-insensitive" or "hormone-refractory" prostate cancer. While numerous therapies impact biochemical response in the setting of CRPC, there remains unmet medical need, largely expressed as the lack of durable response. New therapies that extend survival of patients beyond that provided by chemotherapy are needed. It is hypothesized that the triazole antifungal drug itraconazole, through its activity as a potent inhibitor of the Hedgehog (Hh) signaling pathway via the Smoothened (Smo) pathway, may provide clinical benefit in the treatment of prostate cancer. The Hh signaling pathway is a critical embryonic developmental pathway whose aberrant activity has been implicated in the growth and metastases of a variety of tumor types including prostate cancer. Itraconazole is structurally related to ketoconazole, demonstrated to reduce serum PSA by more than 50% in about 20 to 25% of treated prostate cancer subjects. This study will assess efficacy on the basis of serum levels of PSA, an established surrogate endpoint for efficacy in prostate cancer.