ODM-204 is a novel nonsteroidal compound that has a dual mechanism of action against CYP17A1 and AR. In vitro, ODM-204 inhibited proliferation of VCaP and LNCaP cells. In vivo, oral administration of this compound significantly reduced VCaP xenograft tumour growth in mice. Oral ODM-204 showed potent inhibition of steroid biosynthesis in rats and monkeys. These data formed the basis of the DUALIDES first-in-man study of ODM-204 in castration-resistant prostate cancer (CRPC).