Pharmacokinetic profiles of significant adverse events with crizotinib in Japanese patients with ABCB1 polymorphism

Crizotinib is a standard treatment for advanced ALK-positive non-small-cell lung cancer (NSCLC). We undertook this study to investigate the pharmacokinetics of crizotinib and clinical and pharmacogenomic factors that may increase the risk of adverse events (AEs). We defined clinically significant AEs as grade 4 hematological toxicity, grade ≥3 non-hematological toxicity, and any grade of interstitial lung disease. Eight subjects with ALK-positive NSCLC scheduled to receive crizotinib 250 mg twice daily were studied. Six patients were female and two were male, and most of the patients had low body weight with a median body weight of 46.8 kg (range, 42.4-61.0 kg). All patients developed AEs, five developing six clinically significant AEs. Six patients required dose reduction. In pharmacokinetic analysis, blood samples were obtained on days 1 and 15. The mean area under the plasma concentration-time curve from 0-12 h (AUC0-12 ) on day 15 was significantly increased in patients with clinically significant AEs (n = 5) compared with those without (n = 3) (P = 0.04). Genetic polymorphisms of ABCB1 were analyzed. One patient with the ABCB1 1236TT-2677TT-3435TT genotype was an outlier, with an AUC0-12 and peak concentrations on day 15 of 2.84× and 2.61× the mean, respectively, compared with those with other genotypes. Our results suggest that some Japanese NSCLC patients treated with crizotinib developed clinically significant toxicities that were related to altered pharmacokinetics parameters due to genotype and body weight factors.