Randomized, Double-Blind, Active-Controlled, Parallel, Phase 3 Clinical Trial for Evaluating the Efficacy and Safety of Zastaprazan in Patients with Gastric Ulcers

Abstract

Background/Aims: Zastaprazan (JP-1366) is a novel potassium-competitive acid blocker with a fast onset and prolonged duration. This study aimed to assess the efficacy and safety of zastaprazan versus lansoprazole in patients with gastric ulcers. Methods: A total of 329 subjects with confirmed gastric ulcers participated in a phase 3, multicenter, randomized, double-blind, active-controlled clinical study. Subjects were randomized to receive zastaprazan 20 mg or lansoprazole 30 mg once daily up to 8 weeks. The primary endpoint was the cumulative healing rate of gastric ulcers as confirmed by upper gastrointestinal endoscopy at 8 weeks in patients. Secondary endpoints included ulcer healing rate, symptom recovery, quality of life changes, and safety assessment results. Results: In the per-protocol set, the cumulative healing rate at 8 weeks was 100.00% (146/146) for zastaprazan 20 mg and 97.06% (132/136) for lansoprazole 30 mg, while at week 4, the healing rates were 93.84% (137/146) and 91.91% (125/136), respectively. Zastaprazan was noninferior to lansoprazole in ulcer healing, while the incidence of adverse events was comparable between groups. Gastrin levels increased during the treatment and declined after the treatment in both groups. Conclusions: An 8-week therapy involving zastaprazan 20 mg demonstrated noninferiority to lansoprazole 30 mg in the cumulative rate of healing of gastric ulcers at 8 weeks, and the two demonstrated similar safety profiles. (ClinicalTrials.gov identifier NCT05448001) (Gut Liver, Published online January 16, 2026)