A Study to Investigate the Safety and Tolerability of Oral INR731 Single Agent or in Combination With Androgen Receptor Pathway Inhibitor (ARPI) in Patients With Metastatic Prostate Cancer

This is a first-in-human, open-label, phase I, multi-center study which consists of three treatment arms: INR731 single agent (Arm A), and INR731 in combination with enzalutamide (Arm B) or abiraterone (Arm C). The single agent arm has a dose escalation part followed by a dose expansion part. Once the single agent recommended dose(s) is determined during dose escalation, the study may proceed to dose expansion to further explore safety, tolerability and preliminary anti-tumor activity. The single agent dose expansion part will include a post-standard of care (SOC) metastatic castration resistant prostate cancer (mCRPC) group and patients with time to castration resistance (TTCR) \<12 months. The combination arms have a dose escalation of INR731 in combination with enzalutamide or abiraterone followed by a dose expansion of INR731 in combination with enzalutamide only. The combination dose escalation will be conducted in patients with mCRPC who have progressed following standard of care (post-SOC). During combination escalation, once the safety and tolerability of INR731 with the combination agent(s) is assessed, the study may proceed to dose expansion. The combination dose expansion part will include first-line (1L) mCRPC patients with no prior treatment in the mCRPC setting.