Association of Genetic Polymorphisms With Afatinib-induced Diarrhoea.

Background/aim: Afatinib, a 2 generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) used in treatment of non-small cell lung cancer (NSCLC), causes diarrhoea in over 90% of patients. The association of genetic background with diarrhoea is poorly understood.

Patients And Methods: We evaluated the roles of four single nucleotide polymorphisms (SNPs) in ATP binding cassette subfamily B member 1 (ABCB1) and ATP binding cassette subfamily G member 2 (ABCG2) genes-ABCB1 1236 C>T, 2677 G>T/A, and 3435 C>T, and ABCG2 421 C>A-on treatment-induced diarrhoea in 38 patients with NSCLC treated with afatinib.

Results: Diarrhoea occurred more frequently in patients with ABCB1 2677 T(A)/T(A) (14/16, 87.5%) than in patients with non-T(A)/T(A) alleles (8/22, 36.4%) (p=0.003). ABCB1 2677 T(A)/T(A) was significantly predictive of diarrhoea (p=0.002) by multivariable regression analysis.

Conclusion: Afatinib-induced diarrhoea is associated with the SNP ABCB1 2677 T(A)/T(A).