The AMOR study: a randomized, double-blinded trial of omeprazole versus ranitidine together with amoxycillin and metronidazole for eradication of Helicobacter pylori

Background Besides antibiotics, additionally effective acid inhibition is necessary for the eradication of Helicobacter pylori. Objective To assess the significance of acid suppression and, in particular, treatment with proton pump inhibitors (PPIs) compared with H2 receptor antagonists (H2 RAs). The primary target parameter for the study was H. pylori eradication. In addition, the ulcer healing rate, speed of pain reduction, score for gastritis in the antrum and gastric body, and rate of side effects were recorded. Design Randomized, double-blinded, multicentre study. Participants A total of 456 patients between the ages of 18 and 80 years with H. pylori-positive duodenal ulcers were included in the study. Methods Using a randomization list, patients were assigned either to a treatment group receiving omeprazole 40 mg once daily, amoxycillin 750 mg three times a day, and metronidazole 500 mg three times a day (OAM), or to a group receiving ranitidine 300 mg once daily, amoxycillin 750 mg three times a day, and metronidazole 500 mg three times a day (RAM). The treatment period was 7 days in both groups. Long-term acid-suppressant treatment was not given. Results The eradication rate was 87.1% (169/194, intention to treat [ITT]) in the OAM group and 77% (137/178, ITT) in the RAM group. The difference of 10.1% (95% CI 2.5–18%) is statistically significant (P = 0.0104). The ulcer healing rate was 93.3% in the OAM group (181/194, ITT) and 92.1% in the RAM group (164/178, ITT, NS). With regard to the speed and intensity of pain reduction, the OAM group was superior to the RAM group. In patients in whom H. pylori eradication was successful, the reduction in the antral and gastric body gastritis score was significantly greater than in patients without eradication. In the OAM group, 39.1% of the patients (n = 90) reported one or more side effects, compared with 44.7% (n = 101) in the RAM group (P = 1.5449, NS). Conclusion Omeprazole (40 mg once daily in the morning) is significantly more effective than ranitidine (300 mg once daily in the morning) with respect to H. pylori eradication when used together with amoxycillin (750 mg three times a day) and metronidazole (500 mg three times a day) for a 7-day treatment period.