Genetic Determinants of Dabigatran Plasma Levels and Their Relation to Bleeding
Background—Fixed-dose unmonitored treatment with dabigatran etexilate is effective and has a favorable safety profile in prevention of stroke in atrial fibrillation patients compared to warfarin. We hypothesized that genetic variants could contribute to inter-individual variability in blood concentrations of the active metabolite of dabigatran etexilate, and influence the safety and efficacy of dabigatran.
Methods and Results—We successfully conducted a genome-wide association study in 2,944 RE-LY participants. The CES1 SNP rs2244613 was associated with trough concentrations, and the ABCB1 SNP rs4148738 and CES1 SNP rs8192935 were associated with peak concentrations at genome-wide significance (P<9 x 10-8) with a gene-dose effect. Each minor allele of the CES1 SNP rs2244613 was associated with lower trough concentrations (15% decrease per allele, 95%CI 10-19%; P=1.2 x 10-8) and a lower risk of any bleeding (OR=0.67, 95%CI 0.55-0.82; P=7 x 10-5) in dabigatran-treated participants, with a consistent but non-significant lower risk of major bleeding (OR=0.66, 95%CI 0.43-1.01). The interaction between treatment (warfarin versus all dabigatran) and carrier status was statistically significant (P=0.002) with carriers having less bleeding with dabigatran than warfarin (HR=0.59, 95%CI 0.46-0.76; P=5.2 x 10-5) in contrast to no difference in noncarriers (HR=0.96, 95%CI 0.81-1.14; P=0.65). There was no association with ischemic events, and neither rs4148738 nor rs8192935 was associated with bleeding or ischemic events.
Conclusions—Genome-wide association analysis identified that carriage of CES1 rs2244613 minor allele occurred in 32.8% of patients in RELY and was associated with lower exposure to active dabigatran metabolite. The presence of the polymorphism was associated with a lower risk of bleeding.
Clinical Trial Registration Information—ClinicalTrials.gov; Identifier: NCT00262600
- Received January 10, 2013.
- Accepted February 15, 2013.