INR731

INR731 is an orally bioavailable small molecule inhibitor of the **cholesterol side-chain cleavage enzyme (CYP11A1)**, currently under development by **Novartis** for the treatment of metastatic prostate cancer. CYP11A1 is the rate-limiting enzyme that catalyzes the first step of steroidogenesis, converting cholesterol into pregnenolone. By inhibiting this enzyme, INR731 suppresses the production of all steroid hormones, including androgens and their precursors, which are critical drivers of prostate cancer progression. This mechanism aims to provide a more complete blockade of the androgen signaling axis compared to standard androgen receptor pathway inhibitors (ARPIs), potentially overcoming resistance mechanisms in patients with advanced disease. It is currently being evaluated in Phase I clinical trials as a monotherapy and in combination with standard-of-care ARPIs such as enzalutamide or abiraterone.