Abstract
BACKGROUND Vonoprazan, potassium-competitive acid blocker, is expected to reduce incidence of delayed bleeding after gastric endoscopic submucosal dissection (ESD); however, preliminary data to design a large-scale comparative study are lacking. This study aimed to assess the efficacy of vonoprazan in preventing delayed bleeding after gastric ESD. METHODS In this single-center randomized phase II trial, a modified screened selection design was used with a threshold non-bleeding rate of 89% and an expected rate of 97%. In this design, Simon's optimal two-stage design was first applied for each parallel group, and efficacy was evaluated in comparison with the threshold rate using binomial testing. Patients were randomly assigned in a 1:1 ratio to receive either vonoprazan 20 mg (VPZ group) or lansoprazole 30 mg (PPI group) for 8 weeks from the day before gastric ESD. The primary endpoint was the incidence of delayed bleeding, defined as endoscopically confirmed bleeding accompanied by hematemesis, melena, or a decrease in hemoglobin of ≥ 2 g/dl. RESULTS Delayed bleeding occurred in three of 69 patients (4.3%, 95% CI 0.9-12.2%, p = 0.047) in the VPZ group, and four of 70 (5.7%, 95% CI 1.6-14.0%, p = 0.104) in the PPI group. As only vonoprazan showed significant reduction in delayed bleeding compared with the threshold rate, it was determined to be efficacious treatment. CONCLUSIONS Vonoprazan efficaciously reduced the delayed bleeding rate in patients with an ESD-induced gastric ulcer. A large-scale, randomized, phase III study is warranted to definitively test the effectiveness of vonoprazan compared with proton pump inhibitors.
