BACKGROUND:Proton pump inhibitors (PPIs) are well established as first-line agents for the treatment of moderate-to-severe gastro-oesophageal reflux disease (GORD). Although all PPIs heal oesophageal lesions and provide symptomatic relief, breakthrough symptoms may occur as acidity levels rebound. Pantoprazole magnesium (pantoprazole-Mg) has a longer elimination half-life than pantoprazole sodium (pantoprazole-Na), resulting in prolonged drug exposure. OBJECTIVE:This study compares the clinical efficacy and safety of once-daily pantoprazole-Mg 40 mg with that of once-daily pantoprazole-Na 40 mg in the management of GORD. METHODS:This was a randomized, double-blind, controlled, multicentre study of non-inferiority design in outpatients with GORD. The study was conducted in 53 centres in Germany from 12 May 2003 to 18 September 2003. Male or female outpatients (aged ≥18 years) with endoscopically confirmed GORD stage I-III (according to the Savary-Miller classification modified by Siewert) were enrolled. Using a computer-generated randomization list, patients were randomized to treatment with pantoprazole-Mg 40 mg plus placebo or pantoprazole-Na 40 mg plus placebo, both given once daily for 4 or 8 weeks depending on healing of oesophagitis. The primary objective was endoscopic healing at 8 weeks. RESULTS:The intent-to-treat (ITT) group consisted of 636 patients (322 receiving pantoprazole-Mg and 314 receiving pantoprazole-Na). Endoscopically confirmed healing of reflux oesophagitis after 8 weeks occurred in 87.3% (95% CI 83.1, 90.7) of patients receiving pantoprazole-Mg and 85.0% (95% CI 80.6, 88.8) of patients receiving pantoprazole-Na (ITT population). The lower bound of the 95% CI for the between-group treatment difference was -1.3, which was within the predefined margin of non-inferiority of -10% to 0%. Healing rates after 4 weeks were superior in the pantoprazole-Mg group (72.7% [95% CI 67.5, 77.5]) compared with the pantoprazole-Na group (66.2% [95% CI 60.7, 71.5]), and the one-sided (lower bound) of the 95% CI for the difference between healing rates for the two treatments was within the predefined non-inferiority margin of -10% to 0%. Both treatments had a similar effect on GORD healing in subgroups of patients based on baseline oesophagitis grade and Helicobacter pylori status. Pantoprazole-Mg had similar efficacy to pantoprazole-Na in relieving a broad range of GORD-related symptoms across the course of the study, although symptomatic relief at 4 weeks was numerically higher in the pantoprazole-Mg group than in the pantoprazole-Na group (statistical analyses were not performed). Both treatments were well tolerated; most adverse events were of mild or moderate severity and unrelated to the study medication, and there were no unexpected safety concerns. CONCLUSION:Pantoprazole-Mg is clinically as effective and well tolerated as pantoprazole-Na in the treatment of GORD stages I-III, demonstrating non-inferiority for oesophageal healing at 8 weeks and superior healing rates at 4 weeks associated with high levels of symptomatic relief.