onvansertib + abiraterone + prednisone

This is a **combination therapy** consisting of onvansertib (a highly-selective oral polo-like kinase 1 inhibitor), abiraterone (an androgen biosynthesis inhibitor, typically branded as Zytiga), and prednisone (a synthetic glucocorticoid corticosteroid). This regimen is under investigation for patients with *metastatic castration-resistant prostate cancer (mCRPC)*, especially those who have shown resistance to abiraterone/prednisone therapy. - **Onvansertib** inhibits PLK1, a protein kinase critical for mitosis, which is upregulated in prostate cancer following androgen deprivation and is associated with aggressive disease. Preclinical and early clinical data suggest synergy between onvansertib and abiraterone, with onvansertib restoring sensitivity or enhancing anti-tumor activity through mechanisms independent of androgen receptor signaling[4][5][6]. - **Abiraterone** inhibits CYP17A1, blocking androgen production, thus reducing tumor growth driven by undifferentiated[4][5]. - **Prednisone** is used both to suppress side effects of abiraterone and for its palliative, anti-inflammatory properties. This triple therapy has demonstrated tolerability and signs of efficacy, including PSA stabilization and disease control, in phase 2 trials in mCRPC patients resistant to abiraterone/prednisone[1][3][4][5][6][7].