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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)., (© 2020 John Wiley & Sons Ltd.)

Background: The bacterial resistance of Helicobacter pylori to antimicrobial agents such as clarithromycin and metronidazole has been increasing worldwide, leading to the failure of eradication treatment. Here, we present an eradication regimen consisting of four-times-daily dosing (q.i.d.) of rabeprazole with potent acid inhibition., Aim: To investigate the efficacy of eradication therapy with rabeprazole q.i.d. and amoxicillin or sitafloxacin in Japanese infected with a metronidazole-resistant strain., Methods: We retrospectively investigated the efficacy of eradication regimens with rabeprazole q.i.d. for 7 days in 111 Japanese pooled patients infected with a metronidazole-resistant strain of H. pylori at Hamamatsu University School of Medicine Hospital or the Shiga University of Medical Science Hospital: 1, with sitafloxacin 100 mg twice daily (b.i.d.) (n = 82); 2, with amoxicillin 500 mg q.i.d. (n = 15); and 3, with amoxicillin q.i.d. and sitafloxacin b.i.d.-combined regimen (n = 14). Eradication status was assessed at 8 weeks via a 13 C-urea breath test., Results: Eradication rate on intention-to-treat analysis was 93.7% (95% confidence interval: 87.4-97.4%, 104/111), irrespective of the high prevalence of strains resistant to clarithromycin (81.1%, 90/111) and levofloxacin (42.3%, 47/111). No significant differences in eradication rates were observed among the different treatment regimens (p = .408), eradication history (p = .096) and different CYP2C19 genotypes (p = .789). On multivariate analysis, no significant risk factor for eradication failure by therapy with potent acid inhibition was seen., Conclusion: In Japanese patients infected with metronidazole-resistant strains of H. pylori, eradication rates exceeding 90% can be achieved using appropriate dosing of antibiotic agents with strain susceptibility (amoxicillin q.i.d. and/or sitafloxacin b.i.d.) together with acid inhibition for a full 24 h and rabeprazole 10 mg q.i.d. These findings may be further evidence for dual therapy with rabeprazole q.i.d. and an antibiotic agent (amoxicillin q.i.d. or sitafloxacin b.i.d.) in Japanese patients with metronidazole-resistant strains., (© 2016 John Wiley & Sons Ltd.)

Background: Four times daily dosing (qid) with a proton pump inhibitor can cause rapid increase in intragastric pH. We investigated the efficacy of the front-loading with rabeprazole 10 mg qid on a subsequent regimen with rabeprazole 10 mg twice daily (bid) for 7 days in extensive metabolizers (EMs) of CYP2C19., Methods: Five EMs received three different 1-week regimens in a crossover manner as follows: (1) rabeprazole 10 mg bid for 7 days; (2) a front-loading regimen of rabeprazole (rabeprazole 10 mg qid on day 0 and bid on days 1 to 7); and (3) rabeprazole 10 mg qid for 7 days. Five intermediate metabolizers (IMs) and four poor metabolizers (PMs) received rabeprazole 10 mg bid regimen only. Twenty-four-hour intragastric pH-monitorings were performed on days 1, 4, and 7. Area under the intragastric pH-time curves (AUCs) from days 1 to 7 was calculated using 24-h median intragastric pHs on days 1, 4, and 7., Results: Twenty-four-hour intragastric pHs in the front-loading group on days 1, 4, and 7 were 5.1, 4.9, and 5.1, respectively. The median AUC with front-loading in EMs (34.4, pH·day) was significantly higher than that in EMs with rabeprazole 10 mg bid (30.74, p = 0.043). No statistically significant differences in median AUCs were noted among front-loading in EMs, rabeprazole 10 mg qid in EMs (37.2), rabeprazole 10 mg bid in IMs (37.3), and PMs (39.4)., Conclusions: The one-day front-loading regimen of rabeprazole 10 mg qid provided sufficient acid inhibition for 7 days, even in CYP2C19 EMs.

Background: The incidence and severity of gastroesophageal reflux disease (GERD) in Japan tends to increase in elderly women. Rikkunshito (RKT), a traditional Japanese medicine, acts as a prokinetic agent and improves gastric emptying and gastric accommodation. Our previous prospective randomized placebo-controlled study showed that RKT combined with a standard-dose of rabeprazole (RPZ) significantly improved the acid-related dysmotility symptoms (ARD) in elderly patients with proton pump inhibitor (PPI)-refractory non-erosive reflux disease (NERD). This study aimed to evaluate clinical characteristics of elderly PPI-refractory NERD patients with ARD symptoms who responded to RKT., Methods: Two hundred forty-two patients with PPI-refractory NERD were randomly assigned to 8 weeks of either RPZ (10 mg/q.d.) + RKT (7.5 g/t.i.d.) (RKT group) or RPZ + placebo (PL group). Among them, 95 were elderly (≥65 years) with ARD (RKT group: n = 52; PL group: n = 43). We analyzed the changes using the 12 subscale score of frequency scale for the symptoms of GERD (FSSG) and 15 items of the Gastrointestinal Symptom Rating Scale at 4 and 8 weeks and compared the therapeutic efficacy between the 2 groups., Results: There were no marked differences in baseline demographic or clinical characteristics in the 2 groups except for rate of current smoking. The FSSG score (mean ± SD at 0, 4, and 8 weeks) in both the RKT (16.0 ± 7.0; 9.9 ± 8.4; 7.0 ± 6.4) and PL (15.1 ± 6.4; 10.9 ± 6.7, 11.1 ± 8.5) groups significantly decreased after treatment. However, the degree of improvement of total and ARD scores of FSSG after the 8-week treatment was significantly greater in the RKT group than in the PL group. Combination therapy with RKT for 8 weeks showed significant improvement in 3 subscale scores (abdominal bloating, heavy feeling in stomach and sick feeling after meals) of the ARD domain and 1 subscale score (heartburn after meals) of the reflux symptom domain., Conclusions: RKT may be useful for improving GERD symptoms in elderly PPI-refractory NERD patients with ARD. Thus, RKT was particularly effective for resolving postprandial GERD symptoms (heavy feeling in stomach, sick feeling, and heartburn after meals)., Trial Registration: (UMIN000005880).

Background/Aims: Phase III study demonstrated that vonoprazan-based Helicobacter pylori eradication therapy achieved higher eradication rate compared with lansoprazole. However, there is no study that evaluated the efficacy of vonoprazan in a large sample in real world. We investigated the eradication rate and safety of vonoprazan-based eradication therapy compared with our randomized control trial using second-generation proton pump inhibitor (PPIs). Methods: (First study) A total of 147 patients who have H. pylori infection were randomly assigned to receive either, esomeprazole (EPZ) group and rabeprazole (RPZ) group. (Second study) 1,688 patients who have H. pylori infection underwent primary eradication with triple therapy involving vonoprazan. In both studies, triple therapy with amoxicillin, clarithromycin, and PPI or vonoprazan was performed, and eradication effect was assessed by an urea breath test. Results: (First study) Eradication rate was 77.5% in the EPZ group and 68.4% in the RPZ group; no significant difference was observed between the 2 groups. (Second study) The successful primary eradication rate was 90.8%. There was no severe adverse effect. Conclusions: The eradication rate of vonoprazan-based triple therapy was remarkably higher compared with second-generation PPIs-based triple therapy in real world. Vonoprazan is very likely to become the first option for future eradication therapy. [ABSTRACT FROM AUTHOR]

Introduction: The aim of therapeutic regimens using proton pump inhibitors (PPIs) in patients with acid-related diseases is to potently inhibit acid secretion for the full 24 h. However, optimum treatment is still unclear because the pharmacodynamics of PPIs differ among CYP2C19 genotypes and most of the previous studies have had loss of sample power. Methods: Using pH monitoring, we compared acid inhibition at standard dosage of omeprazole (20 mg, 50 times), lansoprazole (30 mg, 68 times), and rabeprazole (10 mg, 65 times) in Helicobacter pylori-negative healthy young Japanese volunteers. Results: Median pH with rabeprazole was 5.4 (3.3-7.5), which was significantly greater than with either omeprazole [4.4 (2.1-7.3)] or lansoprazole [4.8 (3.5-6.4)] (both P < 0.05). Median 24-h pH differed among the different CYP2C19 genotypes in all three PPIs. In CYP2C19 extensive metabolizers (EMs), the genotype that is refractory to PPI treatment, median pH with omeprazole, lansoprazole, and rabeprazole was 3.8 (2.1-4.4), 4.5 (3.5-5.3) and 4.8 (3.3-7.5), respectively. Discussion: Treatment with the selected PPIs at their standard dosages had difficulty maintaining acid inhibition for a full 24 h, especially in CYP2C19 EM. However, rabeprazole has the merit of less influence of CYP2C19 genotype compared with the other PPIs. [ABSTRACT FROM AUTHOR]

Background Insufficient acid inhibition during Helicobacter pylori eradication treatment and bacterial resistance to antibiotics often causes eradication failure. Four times daily dosing (q.i.d.) of a proton-pump inhibitor ( PPI) achieves potent acid inhibition, suggesting its potential usefulness as a regimen for eradicating H. pylori infection. Therefore, a tailored eradication regimen based on antibiotic susceptibility and maintenance of acid inhibition should have a high success rate. We investigated the efficacy of such treatment based on clarithromycin ( CAM) susceptibility. Methods Using 153 H. pylori-positive Japanese patients, we investigated the efficacy of tailored eradication strategy: (1) Patients infected with CAM-sensitive H. pylori were treated with a PPI (rabeprazole 10 mg q.i.d.), amoxicillin 500 mg q.i.d., and CAM 200 mg b.i.d. (n = 89), and (2) patients infected with CAM-resistant were given the same doses of rabeprazole and amoxicillin and metronidazole 250 mg b.i.d. (n = 64) for 1 week. Results In the tailored regimen group, the overall eradication rate was 96.7% (95% CI: 92.5-98.9%, 148/153) in the intention-to-treat ( ITT) analysis and 97.4% (93.4-99.3%, 148/152) in the PP analysis. The eradication rates for the CAM- and metronidazole-based treatments were similar (95.5% and 98.4%, respectively, p = .400). The tailored treatment achieved a high eradication rate in CYP2C19 rapid metabolizers who were a resistance genotype for PPI treatment (94.3% (86.0-98.4%, 66/70)). Discussion A tailored H. pylori eradication regimen based on CAM susceptibility and maintaining acid secretion (rabeprazole 10 mg q.i.d.) is useful because it can achieve an eradication rate exceeding 95%, irrespective of eradication history, thus overcoming differences among CYP2C19 genotypes. [ABSTRACT FROM AUTHOR]

Anti-platelet drug-induced gastric mucosal injury correlates with intragastric pH. Our aim was to investigate prophylaxis effects of famotidine, one of the representative histamine-2 receptor antagonists (H2RA), on gastric mucosal injury induced by dual therapy with low-dose aspirin and clopidogrel in relation to Helicobacter pylori ( H. pylori) infection and CYP2C19 genotypes. This study was conducted for 20 healthy Japanese volunteers (10 H. pylori-positive and 10-negative subjects) with 100 mg aspirin plus 75 mg clopidogrel (AC) once-daily dosing and AC plus 20 mg famotidine twice-daily dosing (ACH). Mucosal injury was endoscopically assessed on day 3 and 7 and 24-hour intragastric pH and antiplatelet-function test was performed on day 7. Median pH in ACH was similar between CYP2C19 extensive metabolizer (EM) and intermediate metabolizer (IM)/poor metabolizer (PM) and was significantly higher in H. pylori-positive than negative subjects ( P < .05). Mucosal injury with ACH significantly decreased in both day 3 and 7 compared with AC, irrespective with H. pylori and CYP2C19 genotypes ( P < .05). Although antiplatelet effect of clopidogrel in EM was significantly higher than that in IM/PM, the additional famotidine did not affect the effect. Anti-platelet drug-induced gastric injury was alleviated by famotidine without attenuation of anti-platelet functions irrespective of H. pylori and CYP2C19 genotypes. [ABSTRACT FROM AUTHOR]

Background: In esophagus whether antiplatelet drugs, such as low-dose aspirin (LDA) and clopidogrel, induce mucosal injury by pH changes or by acid reflux is unclear. We designed to clarify which mechanism was responsible. Methods: In study 1, 80 patients taking LDA and 80 age- and sex-matched subjects who underwent endoscopy for dyspeptic symptoms or for a health check-up were evaluated the endoscopic incidence of esophageal mucosal injury and severity. In study 2, 35 healthy subjects were treated with LDA 100 mg (regimen A), and then 20 randomly selected subjects were dosed clopidogrel 75 mg (regimen C), LDA/clopidogrel (regimen AC), or LDA/clopidogrel/rabeprazole 10 mg for 7 days. Subjects underwent endoscopy and 24-hour pH measurements on day 7. Results: In study 1, the prevalence of esophageal injury in LDA patients was 40.0%, significantly higher than in non-LDA subjects (25.0%, p = 0.042). In study 2, significant increases in incidence of injury were observed with regimens A (45.8%) and AC (50.0%), but not with C (20.0%), on day 7. Among subjects in whom pH was >5.0 and <4.0 for less than 40% of time, none developed esophageal injury. Conclusions: LDA caused esophageal injury in half of patients and volunteers. Acid-inhibitory drugs effectively prevented the development of LDA-induced, not clopidogrel, esophageal injury. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background and Aim To examine the differences in esophageal histopathology between non-erosive reflux disease ( NERD) and reflux esophagitis ( RE), and to investigate whether baseline esophageal histopathology can predict the therapeutic response to proton pump inhibitors ( PPIs). Method The subjects comprised 94 patients with NERD ( n = 71) or mild RE ( n = 23). Tissue was biopsied from 5 cm above the squamo-columnar junction (SCJ), and the degree or presence of nine histopathological markers was assessed. The patients were treated with rabeprazole ( RPZ) 10 mg once daily for 4 weeks. If complete heartburn relief was not achieved, RPZ was increased to 10 mg twice daily for another 2 weeks, and then to 20 mg twice daily for another 2 weeks if heartburn remained. Results Features of esophageal histopathology 5 cm above the SCJ differed between NERD and RE patients. The esophageal histopathology in patients unresponsive to RPZ was characterized by Protein Gene Product ( PGP) 9.5 negativity in those with NERD, and intraepithelial bleeding in those with RE. In addition, the combination of dilated intercellular spaces ( DIS) (+)/ PGP 9.5 (−) was indicative of strong resistance to PPI therapy in NERD patients. Conclusion The therapeutic efficacy of PPI can be predicted from the features of biopsied esophageal tissue. Factors predictive of resistance to treatment with PPI are negativity for PGP 9.5 in NERD patients and intraepithelial bleeding in RE patients. [ABSTRACT FROM AUTHOR]

Background and Aim: Aspirin enjoys widespread use as an antithrombotic drug, but such ubiquity also increases the risk of gastrointestinal mucosal injury. Recent studies have shown that aspirin can also induce esophageal mucosal injury. We resolved to determine the intragastric pH value necessary to prevent aspirin-induced esophageal mucosal injury. Methods: 15 healthyJapanese volunteers were dosed for 7 days in a four-way random crossover trial with 100 mg entero-coated type aspirin only once daily, 100 mg aspirin + 20 mg famotidine twice daily, 15 mg lansoprazole once daily, or 10 mg rabeprazole once daily. All subjects underwent endoscopy and intragastric pH monitoring on day 7. Results: 7 individuals (46.7%) developed esophageal mucosal injury when ingesting aspirin alone. The incidence of esophageal mucosal injury was reduced however with concomitant dosing of aspirin and famotidine (26.6%; p = 0.193), lansoprazole (0%; p = 0.004), and rabeprazole (6.7%; p = 0.019). Among individuals for whom mean 24-h pH was >5.0 and who experienced pH <4.0 less than 40% of the time, none developed aspirin-induced esophageal mucosal injury. Conclusion: Acid inhibition achieved with a half-dose of a proton pump inhibitor effectively prevented development of aspirin-induced esophageal mucosal injury, whereas a standard dose of a histamine-2-receptor antagonist failed to achieve the same results. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Aspirin is used widely as an antithrombotic drug for the prevention of cardiovascular and cerebrovascular events. Although aspirin increases the risk for gastrointestinal mucosal injury, the effect on esophageal mucosa is unclear. This study investigates whether aspirin induces esophageal mucosal injury and whether a proton-pump inhibitor can prevent such injury in relation to CYP2C19 genotypes. Fifteen healthy Japanese volunteers are dosed for 7 days in a 5-way randomly crossover trial: placebo, aspirin 100 mg, rabeprazole 10 mg, and aspirin 100 mg plus rabeprazole 10 mg either once daily or 4 times per day. All subjects undergo endoscopy and 24-hour intragastric pH monitoring on day 7. With the aspirin regimen, esophageal mucosal disorders occur in 7 patients (46.7%) (5, grade M; 2, grade A). The median 24-hour pH differs significantly among subjects who develop grade MorA gastroesophageal reflux disease and those who do not develop gastroesophageal reflux disease; the median pH in grade A gastroesophageal reflux disease is significantly lower (1.5 [range, 1.1-1.9]) than that in patients without gastroesophageal reflux disease (5.6 [range, 0.8-8.4], P = .04). Rabeprazole signifcantly inhibits acid secretion irrespective of CYP2C19 genotypes and decreases the incidence of aspirin-related esophageal injury and symptoms according to increasing pH value. Aspirin induces esophageal mucosal injury in an acid-dependent manner. Concomitant proton-pump inhibitor therapy may prevent advanced effects of low-dose aspirin. [ABSTRACT FROM AUTHOR]