Effect of cytochrome P450 2C19 genetic polymorphisms on efficacy of rabeprazole or omeprazole-based triple therapy for eradication of Helicobacter pylori

Objective To investigate the efficacy of proton pump inhibitor(PPI)-based triple therapy with amoxicillin, clarithromycin and either rabeprazole or omeprazole in the eradication of Helicobacter pylori(H. pylori) and the impact of cytochrome P450(CYP)2C19 genetic polymorphisms on the eradication rates. Methods One hundred and sixty-nine patients with H. pylori positive chronic gastritis confirmed by endoscopy and histological examination were eligible to this study. H. pylori infection was proven by histology, rapid urease test and serology. Patients were randomly assigned to receive one of the two regimens: clarithmycin 500 mg bid and amoxicillin 1000 mg bid together with either rabeprazole 10 mg bid(RAC group 85 patients) or omeprazole 20 mg bid(OAC group 84 patients) for 1 week. The blood CYP2C19 genotyping was determined by PCR-restriction enzyme analysis. The eradication rates of H.pylori were evaluated by 14C-UBT on the 28th day after completion of treatment.Results One hundred and sixty patients completed the trial. The eradication rates of H. pylori in RAC group and OAC group were 85.9% and 76.8% on the per-protocol analysis, 78.8% and 75.0% on the intention-to-treat analysis, respectively(P0.05). The eradication rates of H. pylori were 95.5%(21/22), 85.9%(73/85) and 67.9%(36/53) in poor metabolizer(PM), intermediate metabolizer(IM) and extensive metabolizer(EM), respectively. Difference was significant between EM and IM or PM(P0.05), but not between PM and IM(P0.05).In RAC group, the eradication rates between PM,IM and EM were not significantly different, respectively(P0.05). However in OAC group, there were significant differences between EM and IM(P0.01) or PM(P0.05), but not between PM and IM(P0.05). Conclusions RAC and OAC triple therapy could eradicate H. pylori effectively. The efficacy of rabeprazole-based triple therapy was less affected by the CYP2C19 genotype. The eradication rates of H. pylori in PM and IM were higher than that in EM.