Efficacy of Vonoprazan (A Novel Oral Potassium-Competitive Acid Blocker)-Based First-Line and Second-Line Eradication Therapy for Helicobacter Pylori Infection

Introduction: Vonoprazan (VPZ) is a novel oral potassium-competitive acid blocker (PCAB), which has higher acid-inhibitory effects comparing with PPIs. Japanese health insurance system approved the use of VPZ for the eradication of Helicobacter pylori in February, 2015. VPZ-based eradication therapy was expected to have higher eradication rate because strong acid suppression was preferable to increase bacterial susceptibility to antibiotics. The aim of this study was to investigate the efficacy of eradication therapy using VPZ comparing with PPI. Methods: As the first-line therapy, patientsinfected with H. pylori administered VPZ (20 mg; bid), amoxicillin (AMOX: 750 mg; bid) and clarithromycin (CAM: 200 mg; bid) for 7 days. Patients who failed firstline therapy administered metronidazole (MNZ) instead of CAM as the second-line therapy. Eradication of VPZ-based therapy was compared with those based on lansoprazole (LPZ: 30 mg; bid) during 2 years prior to release of VPZ. 6-10 weeks after finishing the treatment, results of H. pylori eradication therapy was assessed by either stool antigen test or 13C-UBT, which was used to diagnose H. pylori infection. Results: A total of 82 patients received eradication therapy using VPZ. All the patients completed the regimens without major side effects. The eradication rate of VPZ-AMOX-CAM was 91.0% (60/66; 95% CI: 84.0-97.8%) and significantly higher than that of LPZ-AMOX-CAM was 73.0% (103/141; 95% CI: 65.7-80.4%) (p < 0.05). On the other hand, eradication rate of both PCAB-based and LPZ-based secondline therapies were preferable, 100% (16/16) and 95.0% (19/20), respectively. Conclusion:H. pylori eradication treatments using VPZ were completed without any major side effects. VPZ (PCAB)-based triple therapy was more effective than PPI-based therapy in the first-line eradication therapy.