Cancer Drug Mechanisms AB

Question 1

Abiraterone in prostate cancer - mechanism?

Answer 1

Androgen biosynthesis inhibitor.

Inhibits CYP17, blocking conversion of androgen precursors in testicular, adrenal and prostate tumour tissues.

There is therefore an accumulation of upstream steroids > apparent mineralocorticoid excess (therefore give with Prednisolone to supplement blocked Cortisol)

Question 2

Enzalutamide in prostate cancer - mechanism?

Answer 2

Androgen receptor antagonist (second generation)

• Inhibits binding of androgen to androgen receptor
• Inhibits translocation into nucleus (if it manages to bind)
• Inhibits function of activated androgen receptor

Note - unlike first generation anti-androgens it doesn’t have much in the way of agonist activity

Question 3

PARP inhibitors - mechanism?

Answer 3

Example: Olaparib
Indication: BRCA

PARP are a series of enzymes involved in an alternative DNA repair pathway. Inhibition of this pathways is lethal to cancer but not to normal tissue.