US double-blind, controlled trials of omeprazole and amoxycillin for treatment of Helicobacter pylori.

BACKGROUND

Widely variable Helicobacter pylori eradication rates have been reported with omeprazole/amoxycillin dual therapy. We present the first US double-blind, controlled trials of this dual therapy.

METHODS

Three separate studies were performed: Studies 1 and 2 included patients with an active duodenal ulcer and Study 3 included patients with a documented history of duodenal ulcer. H. pylori eradication regimens in all studies were omeprazole plus amoxycillin vs. omeprazole vs. amoxycillin for 2 weeks. Doses in Study 1 were omeprazole 40 mg b.d. and amoxycillin 500 mg t.d.s., and in Studies 2 and 3 they were omeprazole 20 mg b.d. and amoxycillin 1 g t.d.s. Endoscopic biopsy tests were used for H. pylori diagnosis, and testing for H. pylori eradication was done at least 4 weeks after the completion of therapy. Amoxycillin sensitivities were performed in Study 2.

RESULTS

Intention-to-treat (ITT) and per protocol (PP) analyses showed that eradication rates with omeprazole/amoxycillin [ITT: 39%, 40%, 46% (n = 72, 62, 48); PP: 50%, 46%, 54% (n = 54, 52, 37)] were significantly greater than monotherapy with either omeprazole (ITT: 0-4%); PP: 0-5%) or amoxycillin (ITT: 2-5%; PP: 0-11%). No patients taking the dual therapy discontinued therapy due to adverse events. Amoxycillin resistance was not seen at baseline (n = 76) or after amoxycillin therapy (n = 56).

CONCLUSIONS

Omeprazole/amoxycillin dual therapy is well tolerated but the eradication rate which can be expected in the USA is at best about 50%.