Therapeutic Advances in Gastroenterology (Jun 2017)

A randomized, double-blind study to evaluate the acid-inhibitory effect of vonoprazan (20 mg and 40 mg) in patients with proton-pump inhibitor-resistant erosive esophagitis

  • Katsuhiko Iwakiri,
  • Yuuichi Sakurai,
  • Madoka Shiino,
  • Hiroyuki Okamoto,
  • Kentaro Kudou,
  • Akira Nishimura,
  • Naoki Hiramatsu,
  • Eiji Umegaki,
  • Kiyoshi Ashida

DOI
https://doi.org/10.1177/1756283X17705329
Journal volume & issue
Vol. 10

Abstract

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Background: Standard treatment for patients with erosive esophagitis (EE) is proton-pump inhibitors (PPIs), but some patients are resistant to PPIs. We aimed to evaluate the acid-inhibitory effects and efficacy of a novel potassium-competitive acid blocker (vonoprazan) in patients with PPI-resistant EE. Methods This randomized, double-blind, multicenter study of vonoprazan evaluated gastric and esophageal pH over a 24-hour period as the primary endpoint and EE healing rate as the secondary endpoint. Following a 7 to 14-day run-in period (lansoprazole 30 mg treatment), patients with endoscopically confirmed PPI-resistant EE received vonoprazan 20 mg or 40 mg for 8 weeks. Results Patients were randomized to receive vonoprazan 20 mg ( n = 9) or 40 mg ( n = 10). Over a 24-hour period; both groups showed a significant increase from baseline in the percentage of time gastric pH ≥ 4, referred to as pH 4 holding time ratio (HTR): an increase from 73.21% to 96.46% in the 20 mg group, and from 69.97% to 100.00% in the 40 mg group. Increases from baseline in esophageal pH 4 HTRs were not significant. The 40 mg group showed greater increases in gastric and esophageal pH 4 HTRs compared with the 20 mg group, but differences between groups were not significant. After 8 weeks’ treatment, the healing rate in subjects with baseline EE grades A–D was 60.0% (3/5 patients) in the 20 mg group and 71.4% (5/7 patients) in the 40 mg group. Vonoprazan was generally well tolerated. One patient (40 mg group) experienced four treatment-emergent adverse events (TEAEs) (unrelated to study drug), leading to study discontinuation. Conclusions Vonoprazan 20 mg and 40 mg effectively inhibited gastric acid secretion over a 24-hour period with significantly increased gastric pH 4 HTR, and resulted in an EE healing rate > 60.0% in this study. Vonoprazan treatment may be valuable for patients with PPI-resistant EE