Drug Interaction Report

ADJUST DOSING INTERVAL: Food significantly enhances the oral absorption and bioavailability of alpelisib. When administered with a high-fat high-calorie meal (985 calories with 58.1 g of fat) or a low-fat low-calorie meal (334 calories with 8.7 g of fat) the AUC and Cmax of a single dose of alpelisib was increased by 73% and 84% and 77% and 145%, respectively. There were no clinically significant differences in alpelisib AUC between the two types of meals. In addition, food appears to have a more pronounced effect on the solubility of alpelisib than gastric pH. When coadministered with a single 300 mg dose of alpelisib, ranitidine decreased the absorption and overall exposure of alpelisib. Following administration of ranitidine with a low-fat low-calorie meal, the mean AUC and Cmax of alpelisib was decreased by 21% and 36%, respectively. Administration of ranitidine under fasting conditions reduced the mean AUC and Cmax of alpelisib by 30% and 51%, respectively.

MANAGEMENT: To ensure maximal oral absorption, alpelisib should be administered with a meal.

The effect of grapefruit juice on the pharmacologic activity of caffeine is controversial. One report suggests that grapefruit juice increases the effect of caffeine. The proposed mechanism is inhibition of cytochrome P-450 metabolism of caffeine. However, a well-conducted pharmacokinetic/pharmacodynamic study did not demonstrate this effect. The clinical significance of this potential interaction is unknown.