Pharmacogenetic associations of GATA4 and KCNQ1 with ibrutinib cardiovascular toxicity.

Ibrutinib treatment is often complicated by cardiovascular side effects (CVSEs). The objective of this retrospective pharmacogenetic study is to replicate a previously reported association of 'high-risk' patients, who are homozygous carriers of at least two of GATA4 rs804280 AA, KCNQ1 rs163182 GG, and KCNQ1 rs2237895 AA, with increased risk of hypertension or atrial fibrillation, and explore associations for other pharmacogenes (e.g. CYP3A4 , CYP3A5 , CYP2D6 , and ABCB1 ) with ibrutinib CVSEs. Univariate associations with P  < 0.05 were adjusted for significant pretreatment cardiovascular conditions. In total 57 patients were included in the analysis. In the primary analysis, 'high-risk' patients were not more likely to experience hypertension or atrial fibrillation (70 vs. 41%, chi-square P value = 0.06). In secondary analyses, 'high-risk' patients were more likely to experience any CVSE during treatment (75 vs. 41%, P  = 0.013), develop a cardiac rhythm or function disorder (65 vs. 24%, P  = 0.008), and have a treatment modification due to CVSE (45 vs. 8%, P  = 0.004). Additionally, high-risk homozygous variant genotypes of KCNQ1 rs163182 GG and rs2237895 AA were each associated with an increased likelihood of treatment modifications due to CVSE (40 vs. 11%, P  = 0.021 and 45 vs. 9%, P  = 0.004, respectively) and cardiac rhythm or function disorders (60 vs. 27%, P  = 0.037 and 60 vs. 27%, P  = 0.037). This study found supportive evidence that 'high-risk' genotype was associated with increased ibrutinib CVSEs. Validation of these associations is necessary before prospective trials testing whether personalized ibrutinib treatment approaches improve clinical outcomes.