onapristone + abiraterone

Onapristone + abiraterone is a combination therapy consisting of onapristone, a full progesterone receptor antagonist, and abiraterone acetate, a selective and irreversible inhibitor of CYP17. Onapristone blocks the activity of progesterone receptor, thereby inhibiting progesterone-mediated activation of androgen receptor genes, which may promote tumor growth in prostate cancer cells with specific androgen receptor mutations. Abiraterone inhibits androgen biosynthesis, leading to a decrease in androgen signaling—a critical pathway in prostate cancer. This combination is being investigated for advanced castration-resistant prostate cancer (CRPC), particularly in patients who have progressed on abiraterone or enzalutamide. The rationale for combining these drugs is supported by evidence that anti-progestins may augment the effects of androgen deprivation and overcome resistance mechanisms in prostate cancer[2][4][5][6][7].

Brand names

Zytiga

Other names

abiraterone acetate