Phase 1 Trial: INR731 for mCRPC

INR731 is an oral, investigational anticancer drug now entering first‑in‑human testing for men with metastatic castration‑resistant prostate cancer (mCRPC). It is being evaluated in a global, open‑label Phase 1 study with the primary goal of defining its safety, tolerability, pharmacokinetics, pharmacodynamics, and a recommended dose for further development, rather than demonstrating efficacy at this stage. The exact molecular target and mechanism of action have not been disclosed publicly,  so any more specific classification than “oral drug” would be speculative for now.

The study is built around three treatment arms: INR731 alone, INR731 combined with enzalutamide, and INR731 combined with abiraterone, both of which are established androgen receptor–pathway–targeting agents in metastatic disease. Each arm starts with dose escalation to identify safe dose levels, followed by expansion cohorts to better characterize toxicity and look for early anti‑tumor signals such as PSA changes and radiographic responses. The monotherapy expansion focuses on patients whose metastatic castration‑resistant prostate cancer has progressed despite standard treatments or who developed castration resistance within twelve months, while the combination expansion enrolls men receiving first‑line therapy in the metastatic castration‑resistant setting.

Prior exposure to therapies such as taxanes, PARP inhibitors, and lutetium‑177–based radioligand therapy is allowed, but prior treatment with a cereblon‑based degrader is an exclusion, hinting that INR731 may act through a cereblon‑dependent degradation mechanism even though this is not confirmed in public documents.

Clinical trial.