Background: The recommended dose of erlotinib is 150 mg daily either 1 h before a meal (complete fasting) or 2 h after a meal (2 h post-meal), because of the food effect.
Methods: We conducted a cross-over pharmacokinetic study to compare the fed bioequivalence in the two conditions.
Results: Twenty-three patients with non-small cell lung cancer were included in the analysis. AUC0-24 and C max in the 2-h post-meal status were significantly higher than in the complete fasting status (GMR = 1.33, P < 0.001; GMR = 1.44, P < 0.001, respectively). However, because the concentration of erlotinib did not reach the steady state within 7 days in the complete fasting state, we conducted analyses only on day 14, which showed no significant difference in AUC0-24 or C max between the two conditions. The more rapid increase in AUC0-24 and C min did not produce any earlier and more severe toxic events.
Conclusion: The AUC0-24 increased significantly faster (48-53 % greater) in the 2-h post-meal status than in complete fasting status, which suggested that the two gastric emptying states might differ in their absorption. However, there was no clinically significant difference in bioavailability or toxicity between the two clinically used fed conditions at least in 14 days.