Randomized, Double-Blind, Active-Controlled Phase 3 Study to Evaluate Efficacy and Safety of Zastaprazan Compared With Esomeprazole in Erosive Esophagitis.

Introduction: Zastaprazan is a potent potassium-competitive acid blocker developed to treat gastroesophageal reflux disease. The aim of this study was to evaluate the efficacy and safety of zastaprazan compared with esomeprazole in patient with erosive esophagitis (EE).

Methods: A phase III, multicenter, randomized, double-blind, noninferiority clinical study was conducted with 300 subjects with confirmed EE. Subjects were randomized to receive zastaprazan 20 mg or esomeprazole 40 mg once daily up to 8 weeks. The primary end point was the cumulative proportion of subject with healed EE confirmed by endoscopy at week 8. The secondary end points included the healing rate at week 4, symptom response, and quality of life assessment. Safety profiles and serum gastrin levels were also assessed.

Results: In the full analysis set, the cumulative healing rate at week 8 were 97.92% (141/144) for zastaprazan and 94.93% (131/138) ( P = 0.178) for esomeprazole. The healing rate at week 4 in the zastaprazan group was higher than the esomeprazole group (95.14% [137/144] vs 87.68% [121/138]; P = 0.026). There was no significant difference between groups in healing rates (the per-protocol set) at week 8 and week 4, symptom responses, quality of life assessments, and safety profiles. In addition, serum gastrin levels increased during treatment in both groups, with a significant difference between the 2 groups ( P = 0.047), but both decreased after treatment.

Discussion: An 8-week therapy of zastaprazan 20 mg is noninferior to esomeprazole 40 mg in subjects with predominantly low-grade EE. The healing rate at week 4 appears to be higher for zastaprazan than esomeprazole.