[Vonoprazan: a novel potassium-competitive acid blocker].

A potent, rapid acting potassium-competitive acid blocker, vonoprazan, is introduced for clinical use in Japan. A number of phase III clinical trials comparing the efficacy of vonoprazan with lansoprazole, showed non-inferior or superior effectiveness in a spectrum of acid-related diseases. In particular, vonoprazan was superior to regular dose of lansoprazole in healing severe gastroesophageal reflux diseases (Los Angeles grade C and D). A triple therapy regimen with vonoprazan, amoxicillin and clarithromycin for 7 days also showed an excellent eradication rate exceeding 90%. The adverse events across these trials were comparable with the standard dose of lansoprazole. As a consequence of profound acid suppression, serum gastrin during vonoprazan therapy rose to much higher levels than those during lansoprazole therapy, pointing to a requirement for the assurance of long-term safety of vonoprazan.