SUMMARY BackgroundAcid inhibitory effects of proton pump inhibitors (PPIs) are influenced by CYP2C19 genotype. In contrast, the potent acid inhibition of vonoprazan is not influenced by CYP2C19 genotype.

Backgrounds/Aims: Vonoprazan (VPZ) is the first clinically available potassium competitive acid blocker. This class of agents provides faster and more potent acid inhibition than proton pump inhibitors. Most strains of Helicobacter pylori are sensitive to amoxicillin. We hypothesized that dual therapy with VPZ and amoxicillin would provide the sufficient eradication rate for H. pylori infection. To evaluate this, we compared the eradication rate by the dual VPZ/amoxicillin therapy with that by the standard triple VPZ/amoxicillin/ clarithromycin therapy. Methods: Non-inferiority of the eradication rate of H. pylori by the dual therapy with VPZ 20 mg twice daily (bid) and amoxicillin 500 mg 3 times daily

Background: Vonoprazan (V), a potassium-competitive acid blocker, has a more durable acid-inhibitory effect as compared with standard-dose proton pump inhibitors (PPIs) but has not been compared with 2-4 times higher daily PPI doses administered in two divided doses. Aims:To evaluate the acid-inhibitory effect of V 10/20 mg once-daily (OD; V10/ V20) vs rabeprazole (R) 10/20 mg twice-daily (BID; R20/R40) in healthy Japanese volunteers.Methods: This multicentre, randomised, open-label, two-period, crossover study compared V10 or V20 vs R20, or V20 vs R40 using three cohorts of 10 healthy Japanese adults. Within each cohort, subjects were randomised to receive V or R for 7 days and, following a washout period ≥7 days, the other treatment for 7 days. On day 6 of each period, 24-hours multichannel gastric impedance-pH monitoring was performed. Percent times pH ≥ 3, ≥4 and ≥5 (pH 3, 4 and 5 holding time ratios [HTRs])in 24 hours were evaluated as primary pharmacodynamic endpoints.Results: Acid-inhibitory effect (24-hours pH 3 HTR) of V20 was greater than those of R20 (91.0% vs 65.3%; P = .0049) and R40 (98.5% vs 85.9%; P = .0073). Similar results were obtained for 24-hours pH 4 and 5 HTRs. V20 also achieved greater nocturnal pH 4 (91.5% vs 73.2%; P = .0319) and 5 HTRs (78.8% vs 62.2%; P = .0325) as compared with R40. One subject (20%) developed diarrhoea while receiving R40 which was considered treatment-related.Conclusions: Compared with 2-4 times the standard daily dose of R, V20 exerts a more potent and durable acid-inhibitory effect. Trial identifier: UMIN000022198 (www.umin.ac.jp/ctr/index.htm). | 535TAKEUCHI ET Al.

AIG patients were often misdiagnosed as refractory to eradication therapy, probably because achlorhydria in AIG might allow urease-positive bacteria other than H. pylori to colonise the stomach, causing positive C-UBT results.

Eradication of H. pylori in patients allergic to penicillin should be performed using regimens without penicillin derivatives. We treated a total of 28 patients allergic to penicillin with a proton pump inhibitor (PPI), metronidazole (250 mg bid) and sitafloxacin (100 mg bid) for one to two weeks. At four to eight weeks after the treatment, the patients underwent the [ 13 C]-urea breath test. The overall eradication rate was 100.0%. Mild adverse events were observed. Triple therapy with a PPI, metronidazole and sitafloxacin is well tolerated and effective for the eradication of H. pylori in patients allergic to penicillin.