The OAC and OMC options

Objective In three studies, the two most successful regimens in the MACH1 s tudy (omeprazole-amoxycillin-clarithromycin (OAC) and omeprazole-metronidaz ole-clarithromycin (OMC)) were investigated further. Design Double-blind, randomized, international, multi-centre studies with p arallel groups. Setting The studies were performed at centres in France, Germany, Ireland, Norway, Sweden and the UK (MACH2), Canada (DU-MACH) and Germany, Hungary an d Poland (GU-MACH), Participants and interventions In MACH2, the influence of omeprazole on era dication was investigated in patients with duodenal ulcers in remission, us ing OAC, AC, OMC and MC, In DU-MACH and GU-MACH, eradication and relapse ra tes were investigated in patients with active peptic ulcers, using: OAC, OM C and omeprazole alone, Main outcome measures Eradication of Helicobacter pylori, In patients with active peptic ulcer, ulcer healing was also assessed. Results In MACHP (n = 514, intention-to-treat (ITT) analysis), the addition of omeprazole to AC increased the eradication rate from 26 to 94%. The cor responding increase for MC/ OMC was from 69 to 87%. The efficacy of the AC and OAC regimens was unaffected by primary metronidazole resistance, while that of MC was halved and that of OMC reduced by 15%. Clarithromycin resist ance was uncommon. In DU-MACH and GU-MACH (n = 146 and 145, ITT analysis), eradication rates were high with both regimens, Ulcer healing rates were al so high in all treatment groups; ulcer relapse was significantly less frequ ent in the OAC and OMC groups. All regimens were well tolerated. Conclusion Omeprazole triple therapy is highly effective in patients with a ctive or healed peptic ulcer disease, and is well tolerated, fur J Gastroen terol Hepatol 11 (suppl 2):S9-S17 (C) 1999 Lippincott Williams & Wilkins.