Administration of Lapatinib with Food Increases Its Plasma Concentration in Chinese Patients with Metastatic Breast Cancer: A Prospective Phase II Study

LESSONS LEARNED: Administration of lapatinib with food significantly increased its plasma concentration in Chinese patients with metastatic breast cancer. There were no serious adverse events during the study and no significant differences in lapatinib‐related adverse events between the fasted and fed states. BACKGROUND: Lapatinib, a small molecular reversible dual tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR) and human epidermal growth receptor 2 (HER2), was approved for use in combination with capecitabine to treat metastatic HER2‐positive breast cancer. Administration of lapatinib in the fasted state was recommended; however, our preliminary phase II trial data showed that administration of lapatinib with food increased its concentration. METHODS: This study was a single‐center, open‐label, and prospective self‐controlled clinical study. Ten Chinese patients with metastatic breast cancer were enrolled from June 2017 to April 2018. They were required to receive lapatinib plus physician's choice of chemotherapy. Patients were required to take lapatinib orally on an empty stomach continually for 10 days, and then take lapatinib with food continually for the next 10 days. Plasma concentration was measured by liquid chromatography on the 9th and 10th day of each state. RESULTS: Area under the concentration‐time curve (AUC) of the fasted state and the fed state was 21.23 ± 8.91 mg*h/L (coefficient of variation (CV)% 42%) and 60.60 ± 16.64 mg*h/L (CV% 27%), respectively. The mean plasma concentration in the fasted state was 0.88 ± 0.39 mg/L (CV% 45%), and that in the fed state was 2.53 ± 0.77 mg/L (CV% 30%). Compared with taking lapatinib on an empty stomach, receiving lapatinib with food significantly increased the plasma concentration of lapatinib (Wilcoxon match‐paired test, p = .005). In addition, there were no serious adverse events during the study or significant difference in lapatinib‐related adverse events between the two states. CONCLUSION: Our study shows that receiving lapatinib with food can increase its plasma concentration with no significantly increased drug‐related toxicity. We suggest that a larger‐sample‐size clinical trial is needed to fully understand the effect of administration of lapatinib with food.