Assessment of a new triple agent regimen for the eradication of Helicobacter pylori and the nature of H. pylori resistance to this therapy in Japan. 
Multiple regimens for the eradication of Helicobacter pylori have been tested, but the best therapy has not been determined yet.  To determine the efficacy of a new triple agent regimen using a combination of lansoprazole, amoxicillin, and clarithromycin against Helicobacter pylori (H. pylori), and to examine H. pylori resistance to this therapy in ineffective cases.  We studied a total of 71 patients infected with H. pylori who had gastric ulcer (n = 37) or duodenal ulcer (n = 34) as confirmed by endoscopy.  Patients received 1500 mg amoxicillin, 400 mg clarithromycin and 30 mg lansoprazole for 2 weeks followed by 30 mg lansoprazole for 6 weeks in patients with gastric ulcer or for 4 weeks in those with duodenal ulcer.  Endoscopic examination was performed before treatment and at 1 month, 2 months, and 5 months after initiating treatment to check the status of ulceration and H. pylori infection.  The eradication rate of H. pylori was 92% (CI, 83-100%) in the gastric ulcer group and 94% (CI, 86-100%) in the duodenal ulcer group at 5 months, as determined by per-protocol analysis.  Resistance to clarithromycin was present in 1 of 71 (1%) patients before treatment and in 2 of 5 (40%) patients after treatment.  No resistance to amoxicillin and lansoprazole was found in patients before or after treatment.  The resistance to clarithromycin changed during the observation period.  The new triple agent regimen was effective against H. pylori.  Resistance to clarithromycin may not be permanent and it might be one of the risk factors which affect the efficacy of a clarithromycin-based therapy.