1. ¹Center for Clinical Research, Hamamatsu University School of Medicine, Hamamatsu, Japan
2. ²Department of Laboratory Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
3. ³Department of Gastroenterology, Yaizu City Hospital, Shizuoka, Japan
4. ⁴First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
5. ⁵Department of Clinical Pharmacology and Therapeutics, Clinical Pharmacology Center, Faculty of Medicine, Oita University, Oita, Japan
6. ⁶Department of Clinical Pharmacology and Pharmacy, School of Pharmaceutical Sciences, Teikyo-Heisei University, Chiba, Japan

Correspondence: T Furuta, (furuta@hama-med.ac.jp)

Received 29 June 2006; Accepted 16 October 2006; Published online 10 January 2007.

Abstract

Helicobacter pylori eradication rates by triple therapy with a proton pump inhibitor, amoxicillin, and clarithromycin at standard doses depend on bacterial susceptibility to clarithromycin and patient CYP2C19 genotypes. We examined the usefulness of a personalized therapy for H. pylori infection based on these factors as determined by genetic testing. First, optimal lansoprazole dosing schedules that would achieve sufficient acid inhibition to allow H. pylori eradication therapy in each of different CYP2C19 genotype groups were determined by a 24-h intragastric pH monitoring. Next, 300 H. pylori-positive patients were randomly assigned to the standard regimen group (lansoprazole 30 mg twice daily (b.i.d.)), clarithromycin 400 mg b.i.d., and amoxicillin 750 mg b.i.d. for 1 week) or the tailored regimen group based on CYP2C19 status and bacterial susceptibility to clarithromycin assessed by genetic testing. Patients with failure of eradication underwent the second-line regimen. The per-patient cost required for successful eradication was calculated for each of the groups. In the first-line therapy, the intention-to-treat eradication rate in the tailored regimen group was 96.0% (95% CI=91.5–98.2%, 144/150), significantly higher than that in the standard regimen group (70.0%: 95% CI=62.2–77.2%, 105/150) (P<0.001). Final costs per successful eradication in the tailored and standard regimen groups were $669 and $657, respectively. In conclusion, the pharmacogenomics-based tailored treatment for H. pylori infection allowed a higher eradication rate by the initial treatment without an increase of the final per-patient cost for successful eradication. However, the precise cost-effectiveness of this strategy remains to be determined.