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.