Comparison of Cabazitaxel/Prednisone Alone or in Combination With Custirsen for 2nd Line Chemotherapy in Prostate Cancer

Until recently, options for second-line chemotherapy in CRPC have included docetaxel retreatment, mitoxantrone, or other chemotherapies, without proven clinical benefit. In 2010, a Phase 3 second-line chemotherapy trial (TROPIC) showed a survival advantage for cabazitaxel, a semi-synthetic taxane selected to overcome the emergence of taxane resistance, when compared to mitoxantrone. Clusterin is a stress-activated cytoprotective chaperone up-regulated by a variety of anti-cancer therapies that confers treatment resistance when over-expressed. Inhibition of clusterin expression using custirsen has been shown to enhance tumor cell death following treatment with chemotherapy. The clinical activity of custirsen in combination with the taxane docetaxel has been shown in two Phase 2 studies. Given the results observed using a taxane as either first-line or second-line chemotherapy in CRPC, combination with custirsen may decrease taxane resistance and enhance the survival benefit of taxane therapy. Thus, a combination of custirsen with cabazitaxel may further enhance survival in second-line taxane chemotherapy for CRPC.