Mechanism of Action

Abiraterone acetate, marketed under the brand name ZYTIGA, is an orally active inhibitor of the enzyme 17α-hydroxylase/C17,20-lyase (CYP17). This enzyme is crucial in androgen biosynthesis and is expressed in testicular, adrenal, and prostatic tumour tissues. By inhibiting CYP17, abiraterone acetate reduces the production of testosterone and other androgens, which are key drivers of prostate cancer growth. The inhibition is both selective and irreversible, as it covalently binds to the enzyme, blocking androgen production at multiple sources: the testes, adrenal glands, and the tumor itself.