Pilot Studies to Identify the Optimum Duration of Concomitant Helicobacter pylori Eradication Therapy in Thailand

Background and Aim: Eradication rate for Helicobacter pylori infection with standard triple therapy has globally declined including in Thailand, and new regimens are required that provide reliable high eradication rates. The study was designed to determine whether concomitant therapy administered for either 5 or 10days would produce a ≥95% (grade A) treatment success in H. pylori infected Thai subjects with nonulcer dyspepsia. Methods: Two prospective, but separate, pilot single-center studies were carried out during September 2009-December 2010 at Thammasat University Hospital, Thailand. H. pylori infected subjects were randomized into the two pilot studies; either 5-day or 10-day concomitant therapy. Thai concomitant therapy consisted of rabeprazole (20mg) twice daily, amoxicillin 1g twice daily, metronidazole 400mg three times a day, and clarithromycin MR 1g once daily. H. pylori status was assessed by ¹³C-urea breath test 4weeks after completion of the treatment. Successful treatment was defined as achieving a grade A result (≥95%) and failure by <90% cured. Results: A total of 110 subjects were randomized (55 to the 5-day treatment trial and 55 to the 10-day regimen). Baseline subject demographic and clinical characteristics were similar in both studies. All subjects completed their assigned therapies. The 10-day concomitant treatment trial was successful in 53 of the 55 subjects (96.4%; 95% CI 87.4-99.5%). The 5-day concomitant pilot was judged to be a failure as only 49 of 55 subjects (89.1%; 95% CI=77.7-95.8%) were cured. The frequency of adverse events was low and similar in the two studies. Conclusion: The 10-day concomitant regimen provided excellent treatment success (eradication rate >95%) and was well tolerated. Ten-day concomitant therapy is likely to become useful first-line H. pylori eradication in Thailand.