Effects of ketoconazole and esomeprazole on the pharmacokinetics of pazopanib in patients with solid tumors.

Purpose: The metabolism of pazopanib is primarily mediated by CYP3A4. The solubility of pazopanib is pH-dependent, and an elevated gastric pH may decrease its bioavailability. This study evaluated the effect of a potent CYP3A4 inhibitor, ketoconazole, and the proton pump inhibitor esomeprazole on the pharmacokinetics and safety of pazopanib and its metabolites.