title: The OAC and OMC options.
abstract: OBJECTIVE
  In three studies, the two most successful regimens in the MACH1 study (omeprazole-amoxycillin-clarithromycin (OAC) and omeprazole-metronidazole-clarithromycin (OMC)) were investigated further.
  
  
  METHODS
  Double-blind, randomized, international, multi-centre studies with parallel groups.
  
  
  METHODS
  The studies were performed at centres in France, Germany, Ireland, Norway, Sweden and the UK (MACH2), Canada (DU-MACH) and Germany, Hungary and Poland (GU-MACH).
  
  
  METHODS
  In MACH2, the influence of omeprazole on eradication was investigated in patients with duodenal ulcers in remission, using OAC, AC, OMC and MC. In DU-MACH and GU-MACH, eradication and relapse rates were investigated in patients with active peptic ulcers, using: OAC, OMC and omeprazole alone.
  
  
  METHODS
  Eradication of Helicobacter pylori. In patients with active peptic ulcer, ulcer healing was also assessed.
  
  
  RESULTS
  In MACH2 (n = 514, intention-to-treat (ITT) analysis), the addition of omeprazole to AC increased the eradication rate from 26 to 94%. The corresponding 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 resistance 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 also high in all treatment groups; ulcer relapse was significantly less frequent in the OAC and OMC groups. All regimens were well tolerated.
  
  
  CONCLUSIONS
  Omeprazole triple therapy is highly effective in patients with active or healed peptic ulcer disease, and is well tolerated.
authors.affiliation: Department of Medicine, Länssjukhuset Gävle Sandviken, Gävle, Sweden. peter.unge@lsgs.lg.se
authors.forename: P
authors.initials: P
authors.lastname: Unge
mesh_terms: D000658:Amoxicillin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D000897:Anti-Ulcer Agents / Q000627:therapeutic use*; D017291:Clarithromycin / Q000627:therapeutic use; D004311:Double-Blind Method; D004352:Drug Resistance, Microbial; D004359:Drug Therapy, Combination; D016481:Helicobacter Infections / Q000188:drug therapy*; D016480:Helicobacter pylori; D006801:Humans; D008795:Metronidazole / Q000627:therapeutic use; D015337:Multicenter Studies as Topic; D009853:Omeprazole / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D000897:Anti-Ulcer Agents; D008795:Metronidazole; D000658:Amoxicillin; D017291:Clarithromycin; D009853:Omeprazole