Castrate resistant prostate cancer cell lines exhibiting resistance to the androgen-receptor antagonist enzaluatamide overexpress one or both of IGFBP-2 or IGFBP-5 when compared to non-resistant cell lines. Oligonucleotides that target IGFBP-2 and IGFBP-5 can be used to overcome this resistance or as part of a treatment program when administered concurrently with the administration of androgen-receptor antagonist treatments.