Effects of CYP3A4/5 and ABC transporter polymorphisms on osimertinib plasma concentrations in Japanese patients with non-small cell lung cancer

Background The effects of polymorphisms in CYP3A4 (20230G > A), CYP3A5 (6986A > G), ABCB1 (1236C > T, 2677G > T/A, 3435C > T), ABCG2 (421C > A), and ABCC2 (-24C > T) on the area under the concentration-time curve (AUC) of osimertinib in 23 patients with non-small cell lung cancer were investigated. Methods Blood sampling was performed just prior to and at 1, 2, 4, 6, 8, 12, and 24 h after osimertinib administration at the steady-state on day 15 after beginning therapy. Results There were significant correlations of the osimertinib AUC 0-24 with age ( P = 0.038), serum albumin ( P = 0.002), and serum creatinine ( P = 0.012). Additionally, there were significant differences in the AUC 0-24 of osimertinib among the groups administered vonoprazan, histamine 2-receptor antagonists or esomeprazole, and no acid suppressants ( P = 0.021). By contrast, there were no significant differences in the AUC 0-24 of osimertinib between genotypes of CYP3A4/5 or ABC transporters. Furthermore, there were no significant differences in the AUC 0-24 of osimertinib between patients with diarrhea, skin rash, or hepatotoxicity and those without these conditions. In multivariate analysis, only serum albumin value was an independent factor predicting the AUC 0-24 of osimertinib. Conclusions Analysis of CYP3A4/5 and ABC transporter polymorphisms before osimertinib therapy may not predict the efficacy or side effects of osimertinib. However, lower serum albumin values were associated with an increase in the AUC 0 − 24 of osimertinib. After beginning osimertinib therapy, periodic measurement of serum albumin values should be performed.