Evaluation of CYP2C9- and VKORC1-based pharmacogenetic algorithm for warfarin dose in Gaza-Palestine

Aim To evaluate applicability of CYP2C9*2, *3 and VKORC1-1639G > A based algorithm to predict warfarin stable dose (WSD) in a group of Palestinian patients. Patients & methods Warfarin doses were retrospectively calculated for 101 Palestinian patients under warfarin therapy using three models. Performance of the three models was assessed in 47 patients found to take WSD. Results Frequency of CYP2C9*2, *3 and VKORC1-1639G > A alleles is 13.6, 0.0 and 46.5% respectively. The international warfarin pharmacogenetics consortium algorithm was more reliable (MAE = 8.9 ± 1.4; R2 = 0.350) than both the clinical algorithm (MAE = 10.4 ± 1.4; R2 = 0.128;) and the fixed-dose algorithm (MAE = 11.1 ± 1.7). Conclusion The international warfarin pharmacogenetics consortium algorithm can be reliably applied for predicting the WSD in Palestinian population.