ODM-204, a novel dual inhibitor of CYP17A1 and androgen receptor for the treatment of castration-resistant prostate cancer.

Abstract

230 Background: Castration-resistant prostate cancer (CRPC) is characterized by high androgen receptor (AR) expression and persistent activation of AR signaling axis by residual tissue androgens. Inhibiting AR and androgen biosynthesis together may be more effective than inhibiting either alone to treat CRPC. ODM-204 is a potent, orally administered investigational non-steroidal dual inhibitor of CYP17A1 and AR. In vivo, ODM-204 shows favourable pharmacokinetic/ pharmacodynamics (PK/PD) properties in intact mature male monkeys and strong antitumor activity in VCaP xenograft. Methods: The inhibition of CYP17A1 by ODM-204 was studied by using human testicular microsomes and adrenal cortex cell line. Potency to human AR was demonstrated in cells stably transfected with the full-length AR and androgen-responsive reporter gene constructs. PK/PD relationships were evaluated in intact male mature monkeys after single and multiple doses of ODM-204 (10-30 mg/kg/day) by measuring plasma PK after several time points and serum testosterone (T), dehydroepiandrosterone (DHEA), luteinizing hormone (LH), aldosterone, and cortisol 5 hours after the daily dose. Efficacy was further studied in VCaP xenograft in intact male nude mice treated with ODM-204, enzalutamide (enza), abiraterone (abi), or enza+abi-combination for 28 days. Results: ODM-204 binds to AR with a high affinity (Ki47 nM) and selectivity, and has a high potency towards CYP17A1 (IC5022 nM). In intact monkeys, ODM-204 was well tolerated and showed good oral bioavailability with linear and dose proportional pharmacokinetics. Already after a single oral dose of ODM-204, serum T and DHEA were markedly suppressed. After multiple days of dosing, LH was increased, however, changes in cortisol and aldosterone were only minimal. In VCaP xenograft model, ODM-204 showed significant antitumor activity, better than single agent enza or abi, or their combination. Conclusions: ODM-204 is a novel, dual CYP17A1 and AR inhibitor for the treatment of CRPC. A clinical phase 1/2 dose-escalation trial (NCT02344017) is ongoing in patients with mCRPC to determine PK, PD, safety and anti-tumor activity of ODM-204.