Purpose: We aimed to study potential variables involved in interindividual variability to acenocoumarol (AC) response in order to establish a pharmacogenetic algorithm (PA) that includes clinical and genetic factors to predict adequate AC dose to stabilize anticoagulation in a cohort of Tunisian patients.
Methods: Genotyping of the CYP2C9, VKORC1, CYP4F2, and CALU polymorphisms was conducted on 246 patients using PCR-RFLP technique. AC normalized maintenance dose (NMD): ((mean maintenance dose/international normalized ratio (INR)) equilibrium) was calculated. The statistical study was carried out with SPSS V20.
Results: A significant correlation was found between age, BMI, and daily AC dose (r = - 0.397; p < 0.001 and r = 0.215; p = 0.001, respectively). The carriers of mutated alleles CYP2C9*2 or CYP2C9*3 or VKORC1 haplotypes (H1 and H7) were associated with AC hyper-sensibility. After adjustment to potential covariates, these patients presented supra-therapeutic INR during treatment period and needed low AC dose (ORs* = 0.28 [0.06-0.60], p = 0.004; ORs* = 0.12 [0.04-0.05], p < 0.001; ORs* = 0.45 [0.24-0.84], p = 0.01; and ORs* = 0.28 [0.06-0.98], p = 0.049, respectively). However, carriers of VKORC1 haplotypes (H3 and H12) or mutated alleles CYP4F2 (rs2108622) or CALU (rs1043550) tend to resist to treatment, hence long period of therapy initiation, and must be treated with high AC dose (ORs* = 2.67 [81.12-5.91], p = 0.013; ORs* = 8.76 [1.07-76.26], p = 0.019; ORs* = 3.12 [1.01-9.63], p = 0.047; and ORs* = 3.96 [1.41-11.09], p = 0.009, respectively). A final multivariate regression model explained 48.1% of the global interindividual variability in AC dose requirement.
Conclusion: The PA demonstrated that VKORC1 and CYP2C9 polymorphisms contribution was more important than clinical factors. Applying the PA would allow dose adjustment to treat patients in a personalized manner.
Keywords: Acenocoumarol; CALU; CYP2C9; CYP4F2; Pharmacogenetic algorithm; VKORC1 haplotypes.