Marginal increase of sunitinib exposure by grapefruit juice.

Purpose: The drug label of sunitinib includes a warning for concomitant use of grapefruit juice (GJ) but clinical evidence for this drug interaction is lacking. The aim of this study is to determine the effect of GJ, a potent intestinal cytochrome P450 (CYP) 3A4 inhibitor, on steady-state sunitinib pharmacokinetics (PK).

Methods: Sunitinib PK was evaluated in eight cancer patients receiving sunitinib monotherapy in a "4 weeks on-2 weeks off" dose regimen.