Randomised clinical trial: safety, tolerability, pharmacokinetics and pharmacodynamics of repeated doses of TAK-438 (vonoprazan), a novel potassium-competitive acid blocker, in healthy male subjects

Fourteen-day vonoprazan and low- or high-dose amoxicillin dual therapy for eradicating Helicobacter pylori infection: A prospective, open-labeled, randomized non-inferiority clinical study

Background and aim

We previously reported that vonoprazan-amoxicillin (VA) dual therapy for 7 or 10 days is not satisfactorily efficacious for Helicobacter pylori (H. pylori) eradication. We aimed to explore the efficacy of VA dual therapy for 14 days as a first-line treatment for H. pylori infection.

Methods

This was a single center, prospective, open-labeled, randomized non-inferiority clinical study conducted in China. Treatment naïve H. pylori infected patients were randomized into two groups: 20 mg vonoprazan (VPZ) b.i.d. in combination with low-dose (1000 mg b.i.d.) or high-dose (1000 mg t.i.d) amoxicillin for 14 days. 13C-urea breath tests were used to access the cure rate at least 4 weeks after treatment.

Results

A total of 154 patients were assessed and 110 subjects were randomized. The eradication rate of VPZ with b.i.d. amoxicillin or t.i.d. amoxicillin for 14 days was 89.1% and 87.3% by intention-to-treat analysis, respectively, and 94.1% and 95.9% by per-protocol analysis, respectively. The eradication rate and incidence of adverse events were not different between the two groups.

Conclusion

VPZ with b.i.d. or t.i.d. amoxicillin for 14 days provides satisfactory efficacy as a first-line treatment for H. pylori infection in China.

Seven-day vonoprazan-based triple therapy as first-lineHelicobacter pylori treatment in comparison with extended sequential therapy

Background and Aim

Vonoprazan as a new acid blocker has more potency and longer lasting acid suppression than proton pump inhibitors. Whether the efficacy of vonoprazan-based triple therapy is comparable with or even better than that of currently recommended first-line therapies is still unknown. Our study aims to compare the eradication rate and major adverse effects between 7-day vonoprazan-based triple therapy with high-dose amoxicillin and 14-day extended sequential therapy.

Methods

We performed a retrospective analysis from the database of ¹³C-urea breath test at Fu Jen Catholic University Hospital. All patients with a definite diagnosis of Helicobacter pylori infection by rapid urease test, urea breath test, stool antigen test, or pathology report were recruited. Patients receiving first-line regimens with vonoprazan-based triple therapy or extended sequential therapy were included. The respective eradication rate determined by ¹³C-urea breath test and major adverse effects were demonstrated.

Results

Totally, 106 patients were recruited in the vonoprazan-based triple therapy group and 357 in the extended sequential therapy group. There was no significant difference in eradication rate between vonoprazan-based triple therapy with high-dose amoxicillin and extended sequential therapy (83.0 vs 88.8%, P = 0.12). Major adverse effects occurred in 13 of the extended sequential therapy group but none in the other group (0% vs 3.6%, P = 0.046).

Conclusions

Seven-day vonoprazan-based triple therapy with high-dose amoxicillin is a potential first-line anti-Helicobacter pylori regimen alternative to current standard treatment, with the advantages of simplicity, short treatment duration, low pill burden, and fewer major adverse effects.

Randomized clinical trial: A double-blind, proof-of-concept, phase 2 study evaluating the efficacy and safety of vonoprazan 20 or 40 mg versus esomeprazole 40 mg in patients with symptomatic gastro-esophageal reflux disease and partial response to a healing dose of a proton-pump inhibitor

BACKGROUND

Proton-pump inhibitors (PPIs) are cornerstone treatments for gastro-esophageal reflux disease (GERD); however, evidence suggests that most patients exhibit partial response to PPIs, suggesting the need for novel therapies that can provide an improved and sustained increase in gastric pH.

AIMS

This study aimed to determine the effect of vonoprazan, a novel, orally active small-molecule potassium-competitive acid blocker, versus esomeprazole, a PPI, in preventing heartburn symptoms over a 4-week treatment period in patients with GERD and a partial response to esomeprazole treatment.

METHODS

This randomized, double-blind, proof-of-concept, phase 2 clinical trial was conducted between 2016 and 2018 at 39 sites across Europe and designed to evaluate the efficacy and safety of vonoprazan 20 mg once daily (q.d.) and 40 mg q.d. versus esomeprazole 40 mg q.d. after 1:1:1 randomization of symptomatic patients with GERD and a partial response to a healing dose of esomeprazole.

RESULTS

Overall, 256 eligible patients (female, 59.4%; mean age, 52.6 years) received vonoprazan 20 mg (n = 85), vonoprazan 40 mg (n = 85), or esomeprazole 40 mg (n = 86); mean (SD) percentages of heartburn-free 24-h periods during double-blind treatment were 36.7% (33.4%), 36.5% (35.6%), and 38.4% (34.8%), respectively, with no intergroup statistical significance. Vonoprazan exposure increased proportionally from the 20-mg to 40-mg dose (mean C_max : 23.3 ng/ml to 47.1 ng/ml, respectively). Most treatment-emergent adverse events were mild, with no deaths reported.

CONCLUSIONS

No statistically significant difference in efficacy and safety was observed among treatment groups, and vonoprazan was well tolerated. The trial is registered with the National Board of Health (EudraCT: 2015-001154-14) database.

[Treatment of Acid-related Diseases Using Potassium-competitive Acid Blockers]

Proton pump inhibitors (PPIs) have several limitations to their efficacy including insufficient acid suppression, slow onset of action, and variable efficacy among patients due to CYP2C19 metabolism. Potassium-competitive acid blockers inhibit H⁺-K⁺-ATPase in a reversible and K⁺-competitive manner, are novel acid suppressive drugs with rapid onset of action, meal independence, and prolonged control of intragastric acidity compared to PPIs. Potassium-competitive acid blockers exhibited non-inferior therapeutic efficacies on reflux esophagitis, gastric ulcers, and Helicobacter pylori eradication. The review is focused on the unmet needs across the acid-related diseases and recent updates on clinical studies using vonoprazan and tegoprazan.

Vonoprazan and high-dose amoxicillin dual therapy for Helicobacter pylori first-line eradication: A single-arm, interventional study

Background

To date, no interventional trial has assessed the efficacy and safety of vonoprazan and high-dose (500 mg four times daily, 2000 mg/day) amoxicillin dual therapy in terms of Helicobacter pylori eradication. We explored whether this was an appropriate first-line treatment.

Methods

This prospective, dual-center, single-arm interventional study was performed in Japan. Twenty H. pylori-positive patients lacking any eradication history were treated with vonoprazan 20 mg twice daily and amoxicillin 500 mg four times daily (qid) for 7 days. Eradication was evaluated using a stool H. pylori antigen test. We evaluated safety using patient questionnaires. This study was registered in the jRCT database (jRCT031200128).

Results

The intention-to-treat and per-protocol eradication rates were 90% (95% confidence interval [CI] 68.3-98.8%, n = 20) and 94.4% (95% CI 72.7-99.9%, n = 18) respectively. No significant adverse event was recorded.

Conclusion

Vonoprazan/high-dose amoxicillin dual therapy can be a safe standard first-line therapy. We are now undergoing a randomized controlled trial comparing dual therapy and vonoprazan-based triple therapy.

Randomized controlled trial to evaluate the efficacy and safety of fexuprazan compared with esomeprazole in erosive esophagitis

BACKGROUND

Fexuprazan, a novel potassium-competitive acid blocker, reversibly suppresses the K⁺/H⁺-ATPase enzyme in proton pumps within gastric parietal cells. Fexuprazan’s suppression of gastric acid was maintained in healthy individuals for 24 h in a dose-dependent manner.

AIM

To compare fexuprazan to esomeprazole and establish its efficacy and safety in patients with erosive esophagitis (EE).

METHODS

Korean adult patients with endoscopically confirmed EE were randomized 1:1 to receive fexuprazan 40 mg or esomeprazole 40 mg once daily for eight weeks. The primary endpoint was the proportion of patients with healed EE confirmed by endoscopy at week 8. The secondary endpoints included the healing rate of EE at week 4, symptom response, and quality of life assessment. Safety profiles and serum gastrin levels were compared between the groups.

RESULTS

Of the 263 randomized, 218 completed the study per protocol (fexuprazan 40 mg, n = 107; esomeprazole 40 mg, n = 111). Fexuprazan was non-inferior to esomeprazole regarding the healing rate at week 8 [99.1% (106/107) vs 99.1% (110/111)]. There were no between-group differences in the EE healing rate at week 4 [90.3% (93/103) vs 88.5% (92/104)], symptom responses, and quality of life assessments. Additionally, serum gastrin levels at weeks 4 and 8 and drug-related side effects did not significantly differ between the groups.

CONCLUSION

Fexuprazan 40 mg is non-inferior to esomeprazole 40 mg in EE healing at week 8. We suggest that fexuprazan is an alternative promising treatment option to PPIs for patients with EE.

Multiple Bismuth Quadruple Therapy Containing Tetracyclines Combined with Other Antibiotics and Helicobacter pylori Eradication Therapy

Helicobacter pylori (HP) infection is closely associated with the development of chronic gastritis, peptic ulcer, and gastric cancer. However, the resistance rate of H. pylori strains to antibiotics such as clarithromycin, metronidazole, and levofloxacin has increased significantly, resulting in a significant decrease in the eradication efficacy of commonly used regimens. Tetracycline has received the attention of domestic and foreign scholars because of its low resistance. The purpose of this review is to provide an update on the tetracycline-containing bismuth quadruple eradication therapy for H. pylori infection and review the efficacy and safety of the regimens, hoping to provide guidance for clinical practice.

Efficacy of keverprazan for duodenal ulcer: A phase II randomized, double-blind, parallel-controlled trial

BACKGROUND AND AIM

Considering the limitation of varying acid suppression of proton pump inhibitors, this study was aimed to assess the efficacy, safety, and dose-effect relationship of keverprazan, a novel potassium-competitive acid blocker, in the treatment of duodenal ulcer (DU) compared with lansoprazole.

METHODS

A randomized, double-blind, double-dummy, multicenter, low-dose, high-dose, and positive-drug parallel-controlled study was conducted to verify the non-inferiority of keverprazan (20 or 30 mg) to lansoprazole of 30 mg once daily for 4 to 6 weeks and dose-effect relationship of keverprazan in the treatment of patients with active DU confirmed by endoscopy.

RESULTS

Of the 180 subjects randomized, including 55 cases in the keverprazan_20 mg group, 61 cases in the keverprazan_30 mg group, and 64 cases in the lansoprazole_30 mg group, 168 subjects (93.33%) completed the study. The proportions of healed DU subjects in the keverprazan_20 mg, keverprazan_30 mg, and lansoprazole_30 mg groups were respectively 87.27%, 90.16%, and 79.69% at week 4 (P = 0.4595) and were respectively 96.36%, 98.36%, and 92.19% at week 6 (P = 0.2577). The incidence of adverse events in the keverprazan_20 mg group was lower than that in the lansoprazole_30 mg (P = 0.0285) and keverprazan_30 mg groups (P = 0.0398).

CONCLUSIONS

Keverprazan was effective and non-inferior to lansoprazole in healing DU. Based on the comparable efficacy and safety data, keverprazan of 20 mg once daily is recommended for the follow-up study of acid-related disorders. (Trial registration number: ChiCTR2100043455.).

The role of vonoprazan in patients with erosive esophagitis

Acid suppression is the primary therapy for erosive esophagitis (EE). Although proton pump inhibitors (PPIs) are considered as the first-line medication for EE, 10-20% of patients with Los Angeles C and D grade EE do not gain complete mucosal healing and symptom control despite 8-week double-dose PPI treatment. Vonoprazan is a novel potassium-competitive acid blocker (P-CAB), which blocks the H+, K+-adenosine triphosphatase enzymes in a K+-competitive and reversible manner. Vonoprazan exhibits different pharmacological and pharmacokinetic profiles from conventional PPIs, and has a rapid, potent and sustained acid inhibitory effect. In this review, we summarized and discussed current evidence regarding the role of vonoprazan in terms of mucosal healing, maintaining remission and symptom relief for the management of EE, including the initial and maintenance treatment of EE, as well as for PPI-resistant EE patients. Safety concerns and cost-effectiveness analysis of vonoprazan were also mentioned in the article. As a potent and well-tolerated acid blocker, vonoprazan has the potential to become a novel option for the management of EE.

Vonoprazan Triple and Dual Therapy for Helicobacter pylori Infection in the United States and Europe: Randomized Clinical Trial

BACKGROUND & AIMS

Novel, effective treatments for Helicobacter pylori infection are needed. This study evaluated the efficacy of vonoprazan, a potassium-competitive acid blocker, vs standard treatment on H pylori eradication in the United States and Europe.

METHODS

In a randomized, controlled, phase 3 trial, treatment-naïve adults with H pylori infection were randomized 1:1:1 to open-label vonoprazan dual therapy (20 mg vonoprazan twice daily; 1 g amoxicillin 3 times daily), or double-blind triple therapy twice a day (vonoprazan 20 mg or lansoprazole 30 mg; amoxicillin 1 g; clarithromycin 500 mg) for 14 days. The primary outcome was noninferiority in eradication rates in patients without clarithromycin- and amoxicillin-resistant strains (noninferiority margin = 10%). Secondary outcomes assessed superiority in eradication rates in clarithromycin-resistant infections, and in all patients.

RESULTS

A total of 1046 patients were randomized. Primary outcome eradication rates (nonresistant strains): vonoprazan triple therapy 84.7%, dual therapy 78.5%, vs lansoprazole triple therapy 78.8% (both noninferior; difference 5.9%; 95% confidence interval [CI], -0.8 to 12.6; P < .001; difference -0.3%; 95% CI, -7.4 to 6.8; P = .007, respectively). Eradication rates in clarithromycin-resistant infections: vonoprazan triple therapy 65.8%, dual therapy 69.6%, vs lansoprazole triple therapy 31.9% (both superior; difference 33.9%; 95% CI, 17.7-48.1; P < .001; difference 37.7%; 95% CI, 20.5-52.6; P < .001, respectively). In all patients, vonoprazan triple and dual therapy were superior to lansoprazole triple therapy (80.8% and 77.2%, respectively, vs 68.5%, difference 12.3%; 95% CI, 5.7-18.8; P < .001; difference 8.7%; 95% CI, 1.9-15.4; P = .013). Overall frequency of treatment-emergent adverse events was similar between vonoprazan and lansoprazole regimens (P > .05).

CONCLUSION

Both vonoprazan-based regimens were superior to proton pump inhibitor-based triple therapy in clarithromycin-resistant strains and in the overall study population.

CLINICALTRIALS

gov; NCT04167670.

Clinical trial: seven-day vonoprazan- versus 14-day proton pump inhibitor-based triple therapy for first-line Helicobacter pylori eradication

BACKGROUND

One-week triple therapy with vonoprazan is endorsed by Japanese guidelines as an alternative to proton pump inhibitor (PPI)-based triple therapy for first-line Helicobacter pylori eradication. This contrasts with Western guidelines recommending 2-week PPI-based triple therapy.

AIM

To verify the non-inferiority of 1-week vonoprazan-based triple therapy versus 2-week PPI-based triple therapy as first-line H. pylori eradication in a multiracial Asian cohort.

METHODS

Randomised controlled trial of treatment-naïve patients with H. pylori infection assigned 1:1 to either 7 days amoxicillin 1 g + clarithromycin 500 mg + vonoprazan 20 mg twice per day or 14 days amoxicillin 1 g + clarithromycin 500 mg + omeprazole OR esomeprazole OR rabeprazole 20 mg twice/day. Subjects were randomly assigned to each PPI 1:1:1 Demographics, H. pylori resistance, CYP 2C19 genotype, eradication success and safety profiles were compared between groups.

RESULTS

Between June 2019 and June 2021, 252 of 1097 subjects screened were randomised. 244 (age [SD] 51.7 [14.6]) received vonoprazan- (n = 119) or PPI-based (n = 125) triple therapy. Eradication rates by intention-to-treat analysis were 87.4% (vonoprazan-based triple therapy) versus 88.0% (PPI-based triple therapy. By per protocol analysis: 96.3% (vonoprazan-based triple therapy) versus 94.0% (PPI-based triple therapy). Clarithromycin resistance predicted treatment failure on multivariate analysis: RR 11.4; 95% CI [1.4-96.3], p = 0.025. No significant differences in CYP 2C19 genotypes or adverse events occurred between groups.

CONCLUSION

One-week vonoprazan-based triple therapy achieved comparable efficacy to 2-week PPI-based triple therapy and was well tolerated.

Pharmacodynamics and Pharmacokinetics of the Potassium-Competitive Acid Blocker Vonoprazan and the Proton Pump Inhibitor Lansoprazole in US Subjects

INTRODUCTION

We assessed pharmacodynamics and pharmacokinetics of a potassium-competitive acid blocker and proton pump inhibitor in US subjects.

METHODS

Healthy adults were randomized to 7-day periods of vonoprazan 20 mg once daily followed by lansoprazole 30 mg once daily or the reverse order, separated by ≥ 7 days of washout.

RESULTS

Vonoprazan (N = 40) had higher proportions of 24-hour periods with intragastric pH > 4 than lansoprazole (N = 41,38) on day 1 (62.4% vs 22.6%, P < 0.0001) and day 7 (87.8% vs 42.3%, P < 0.0001). Separation in pH started ∼2.5 hours after the first dose.

DISCUSSION

Vonoprazan provided more rapid and potent inhibition of intragastric acidity than lansoprazole in US subjects.

Scope and Limitations of Current Antibiotic Therapies against Helicobacter pylori: Reviewing Amoxicillin Gastroretentive Formulations

Even though general improvement of quality of life has happened around the globe, statistics show that gastric cancer is still a very serious medical concern in some regions of the world. A big portion of malignant neoplasms that develop inside the stomach are linked to an infection of Helicobacter pylori; in fact, this pathogen has already been categorized as a group 1 carcinogen by the World Health Organization (WHO). Still, the efficacy of current anti-H. pylori therapeutic approaches is insufficient and follows a worrying decreasing trend, mainly due to an exponential increase in resistance to key antibiotics. This work analyzes the clinical and biological characteristics of this pathogen, especially its link to gastric cancer, and provides a comprehensive review of current formulation trends for H. pylori eradication. Research effort has focused both on the discovery of new combinations of chemicals that function as optimized antibiotic regimens, and on the preparation of gastroretentive drug delivery systems (GRDDSs) to improve overall pharmacokinetics. Regarding the last topic, this review aims to summarize the latest trend in amoxicillin-loaded GRDDS, since this is the antibiotic that has shown the least bacterial resistance worldwide. It is expected that the current work could provide some insight into the importance of innovative options to combat this microorganism. Therefore, this review can inspire new research strategies in the development of efficient formulations for the treatment of this infection and the consequent prevention of gastric cancer.

Acid Suppressive Drugs

Histamine H₂ receptor antagonists (H₂RAs) suppress gastric acid production by blocking H₂ receptors in parietal cells. Studies have shown that proton pump inhibitors (PPIs) are superior to H₂RAs as a treatment for acid-related disorders, such as peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD). PPIs reduce gastric acid production by irreversibly inhibiting the H⁺/K⁺ ATPase pump, and they also increase gastric emptying. Although PPIs have differing pharmacokinetic properties, each PPI is effective in managing GERD and PUDs. However, PPIs have some limitations, including short plasma half-lives, breakthrough symptoms (especially at night), meal-associated dosing, and concerns associated with long-term PPI use. Potassium-competitive acid blockers (P-CABs) provide more rapid and profound suppression of intragastric acidity than PPIs. P-CABs are non-inferior to lansoprazole in healing erosive esophagitis and peptic ulcers, and may also be effective in improving symptoms in patients with non-erosive reflux disease. Acid suppressive drugs are the most commonly used drugs in clinical practice, and it is necessary to understand the pharmacological properties and adverse effects of each drug.

A Population Pharmacokinetic Model of Vonoprazan: Evaluating the Effects of Race, Disease Status, and Other Covariates on Exposure

Vonoprazan, a potassium-competitive acid blocker, is under investigation in the United States and Europe for the treatment of erosive esophagitis and Helicobacter pylori infection. Population pharmacokinetic (popPK) analysis allows the identification of factors that could affect drug exposure in population subgroups. Here, we report a popPK model based on pooled data sets of available pharmacokinetic (PK) studies in healthy volunteers and patients with gastroesophageal reflux disease, including erosive esophagitis, from Asia and Europe. This model was used to evaluate the impact of different covariates, including race and disease status, on vonoprazan exposure. We analyzed PK data from 746 patients and 410 healthy volunteers from 15 clinical trials using a nonlinear mixed-effects approach to develop the popPK model. Model development focused on characterizing and quantifying the effects of clinical covariates of race (Asian vs non-Asian) and disease status (gastroesophageal reflux disease vs healthy volunteers) on vonoprazan exposure. Identified clinical covariates included fed/fasting status, race, sex, disease status, weight, serum creatinine, and age. The impact of variations in these clinical covariates on exposure to vonoprazan was smaller than the effect of halving or doubling the dose. PK parameters were similar in Asian and non-Asian populations. Variations in weight, age, and race are not predicted to have a clinically relevant impact on vonoprazan exposure or safety and require no changes in vonoprazan dosing. The limited impact of race on exposure suggests that efficacy and safety data for vonoprazan in Asian populations are translatable to non-Asian populations.

An update of pharmacology, efficacy, and safety of vonoprazan in acid-related disorders

INTRODUCTION

Patients with acid-related disorders (ARDs) of the upper digestive tract remain highly prevalent and need to be continuously investigated to improve their management.

AREAS COVERED

This review provides a summary of the most recent advancements in the treatment of ARDs with particular focus on the new drugs available to overcome the unmet needs of traditional therapies.

EXPERT OPINION

Proton pump inhibitors remain the best therapy in treating ARDs, but a consistent proportion of these patients continues to present mucosal lesions or to experience symptoms despite treatment. These cases pertain mainly to the most severe forms of erosive esophagitis or to non-erosive reflux disease. Also, the increasing rate of patients with H. pylori infection not responding to eradication therapy represents a difficult clinical condition. The recent advent of a new class of antisecretory drugs, such as the potassium competitive acid blockers and, among them the most studied vonoprazan, which are characterized by a better pharmacological profile than PPIs (rapid onset of action, longer lasting acid suppression, control of nocturnal acidity), has the potential to overcome the above-mentioned unmet needs. More research should be done to assess their efficacy in Western populations and their safety in patients treated in the long term.

Patient- and physician-reported satisfaction with gastroesophageal reflux disease (GERD) treatment in Chinese clinical practice

OBJECTIVE

The aim of this study was to assess the level of satisfaction with currently prescribed medications for gastroesophageal reflux disease (GERD) in patients and physicians in China.

METHODS

Physicians across China were invited to complete physician surveys concerning factors affecting the prescription of medication for GERD and their satisfaction through an online questionnaire. The enrolled physicians invited the first five GERD patients who visited them on the same day to complete online patient surveys concerning the satisfaction with medications for GERD and its influencing factors.

RESULTS

In total, 334 physician surveys (response rate 36.82%) and 1409 patient surveys (86.07%) were analyzed. Over half (62.57%) the physicians recommended taking a proton pump inhibitor (PPI) twice daily and the majority (88.02%) recommended taking a PPI for 1 week to 3 months. Factors affecting the prescription were how much it could improve quality of life (84.73%), followed by safety, medication compliance, and efficacy. Approximately 30% of patients reported taking a PPI twice daily and 47.20% reported taking a PPI for 1 week to 3 months. Factor affecting patients' adherence to medications was safety (64.30%), followed by medical insurance, efficacy and convenience. Approximately one-third of physicians and patients did not report "satisfied" or "very satisfied" with medications for GERD, including 10.51% of patients and 12.87% of physicians reporting "dissatisfied" or "very dissatisfied."

CONCLUSION

One-third of GERD patients and physicians were not satisfied or very satisfied with medications for GERD. Novel medications may help optimize the management of GERD.

Determinants of reflux perception in patients with non-erosive reflux disease who have reflux-related symptoms on potassium-competitive acid blocker therapy

BACKGROUND

This study investigated potential determinants of reflux perception in patients with non-erosive reflux disease (NERD) who had reflux-related symptoms on potassium-competitive acid blocker (P-CAB) therapy.

METHODS

This study included 23 patients with reflux-related symptoms despite P-CAB therapy. Esophageal impedance-pH monitoring was performed on P-CAB and the following potential determinants of reflux perception were investigated: reflux nadir pH value; change in pH (baseline-nadir); bolus clearance time; reflux extent; proportions of acid, weakly acidic, and weakly alkaline reflux episodes; and proportions of liquid and mixed reflux episodes.

RESULTS

Overall, ≥ 90% of all and symptomatic reflux episodes were weakly acidic reflux and 63% of symptomatic reflux episodes were reflux episodes with pH ≥ 5. There were no significant differences regarding potential determinants between symptomatic and asymptomatic reflux episodes. However, the proportion of symptomatic reflux episodes was significantly greater with pH < 5 (13.8%) than with pH ≥ 5 (9.5%) (P = 0.0431). In reflux episodes with pH < 5, the proportion of symptomatic reflux episodes was significantly greater in proximal sites (20.6%) than in distal sites (10.6%) (P = 0.0178). Conversely, in reflux episodes with pH ≥ 5, there was no significant difference regarding reflux perception according to reflux extent (proximal: 9.6% vs. distal: 9.0%, P = 0.9337).

CONCLUSIONS

In patients with P-CAB-resistant NERD, reflux symptoms were mainly caused by reflux episodes with pH ≥ 5 on P-CAB therapy. The proportions of symptomatic reflux episodes among reflux sites differed according to reflux pH value; thus, the mechanisms of reflux perception may differ according to reflux pH value.

Effectiveness and safety of vonoprazan-based regimen for Helicobacter pylori eradication: A meta-analysis of randomized clinical trials

WHAT IS KNOWN AND OBJECTIVE

The Helicobacter pylori (H. pylori) eradication rate of proton pump inhibitor (PPI)-based regimen remains decreasing. Vonoprazan (VPZ), a stronger and longer-lasting acid blocker, has been proposed to treatment of H. pylori infection. However, previous reviews did not have a pre-established study protocol and did not conduct a comprehensive search of the database, so the results obtained were not robust. We aimed to perform a meta-analysis to assess the effectiveness and safety of VPZ-based regimens for treatment of H. pylori infection in comparison with other regimens.

METHODS

We conducted a systematic literature search on PubMed, Embase, Cochrane Library, Web of Science, ClinicalTrials and ChiCTR Register. Randomized clinical trials comparing VPZ-based regimens with similar eradication regimens without VPZ in the treatment of H. pylori infection were included. Eradication rate, compliance of the patients and side effects were specified as the primary outcomes. RevMan 5.4 software was used to analyze the RCTs and provide pooled risk ratio (RR) with 95% confidence intervals (CI). Systematic searches, study selection, data extraction, risk of bias assessment and statistical analysis were performed by two independent researchers according to the predesigned criteria on the PROSPERO.

RESULTS AND DISCUSSION

A total of 8 RCTs with 2012 patients qualified for evaluation. The results showed that the eradication rate of VPZ-containing regimens was significantly superior to PPI-containing regimens for both intention-to-treat (RR, 1.14; 95% CI: 1.06-1.23; p = 0.0006) and per-protocol analyses (RR, 1.12; 95% CI: 1.04-1.20; p = 0.003). Subgroup analysis based on treatment regimens, eradication experience and clarithromycin resistance, as well as sensitivity analysis further confirmed this finding. In addition, there was no significant difference in compliance (RR, 1.02; 95% CI: 0.98-0.1.05; p = 0.35) and the frequency of adverse events (RR, 0.84; 95% CI: 0.70-1.00; p = 0.05) between the regimens.

WHAT IS NEW AND CONCLUSION

Compared with PPI-based regimens, the VPZ-containing regimens showed a comparable or even superior eradication rate of H. pylori in terms of overall comparison and comparison of different treatment regimens, eradication experience and clarithromycin resistance. In addition, VPZ-based regimens have better tolerability and fewer adverse events. More future studies are needed to evaluate the impact of some differences in patient characteristics.

TRIAL REGISTRATION

PROSPERO CRD42021229598.

A study for every second day administration of vonoprazan for maintenance treatment of erosive GERD (ESD von GERD): a multicenter randomized cross-over study

BACKGROUND

Vonoprazan is a potassium competitive acid blocker used to treat erosive gastroesophageal reflux disease (GERD) with stronger, more stable acid-suppressing effects than proton pump inhibitors (PPIs). This study clarified the usefulness and superiority of vonoprazan administered every second day over PPIs in the maintenance therapy of erosive GERD.

METHODS

This is a prospective, multicenter, open-label, two-period randomized cross-over study. Patients were randomized to either the vonoprazan-lansoprazole (VP-LZ) group, who were given vonoprazan 10 mg for the first 4 weeks and then lansoprazole 15 mg for the next 4 weeks both administered once every second day, or the lansoprazole-vonoprazan (LZ-VP) group, who were treated in reverse. GERD symptoms were compared using symptom diaries, the frequency scale for symptoms of GERD (FSSG), and the gastrointestinal symptom rating scale (GSRS).

RESULTS

We enrolled 122 patients between December 2017 and May 2019. Symptoms were well controlled in vonoprazan administration and lansoprazole administration were 93.6% and 82.1%, respectively, with a significant difference on McNemar's test (P = 0.003). During the second 4 weeks, 94.4% and 76.7% of patients in the VP-LZ and LZ-VP groups, respectively, were well controlled following for ≥ 6 consecutive days a week (P = 0.009). During the first 4 weeks, 96.7% and 80.0% of patients were well controlled with < 1 weekly in the VP-LZ and LZ-VP groups, respectively, during the first 4 weeks (P = 0.007). GERD symptoms, assessed via FSSG and GSRS, significantly decreased with vonoprazan administration once every second day.

CONCLUSIONS

Vonoprazan administered once every second day could be an effective alternative to PPIs in the maintenance treatment of erosive GERD (UMIN000030393).

Night-time gastric acid suppression by tegoprazan compared to vonoprazan or esomeprazole

AIM

Nocturnal acid breakthrough has been considered an unmet need of proton pump inhibitors. Tegoprazan, a novel potassium-competitive acid blocker, is expected to show improved properties for this unmet need. This study was aimed to compare night-time acid suppression by tegoprazan with that by vonoprazan or esomeprazole, and to explore the effect of CYP2C19 phenotypes on acid-suppressive effects.

METHODS

A randomized, open-label, three-period, six-sequence crossover study was conducted. A single oral dose of tegoprazan 50 mg, vonoprazan 20 mg or esomeprazole 40 mg was administered at night in each period. Continuous intragastric pH was monitored at baseline and after each dosing.

RESULTS

16 healthy subjects (6 CYP2C19 extensive metabolizers, 5 intermediate metabolizers, 5 poor metabolizers) completed the study. After a single dose of tegoprazan, intragastric pH increased more rapidly to over 4 at approximately 1 hour compared to the other treatments, and elevated intragastric pH was maintained stably at night. Tegoprazan exhibited night-time acid suppression for slightly but not significantly longer than vonoprazan, and greater than esomeprazole; % Time pH ≥4 at night-time was 66.0%, 60.5% and 36.1% for tegoprazan, vonoprazan and esomeprazole, respectively. Night-time acid suppression by tegoprazan and vonoprazan was not dependent on CYP2C19 phenotypes, while that by esomeprazole tended to be influenced by CYP2C19 phenotypes.

CONCLUSIONS

Tegoprazan produced more rapid, potent and well sustained night-time acid suppression versus vonoprazan or esomeprazole when administered at night. Furthermore, tegoprazan showed no CYP2C19 phenotype dependency in acid suppression. It suggests the potential of tegoprazan, especially in preventing nocturnal acid breakthrough.

Vonoprazan in the management of gastric/peptic ulcers: a systematic review of safety data

Introduction

Although potassium-competitive acid blockers (P-CABs) prompted safety concerns when first developed, they ultimately proved to have a favourable safety profile.

Aim

To assess the safety of vonoprazan in the management of gastroesophageal reflux disease (GERD), peptic ulcers, or gastroduodenal mucosal lesions induced by chronic use of aspirin or non-steroidal anti-inflammatory drugs (NSAIDs).

Material and methods

From March to June 2021, a literature search was conducted using Medline via PubMed, Cochrane library, Lilacs, SciELO, and Centre for Reviews and Dissemination (CRD) electronic databases. After applying the eligibility criteria, 10 studies were included in this review. Of these 10 articles, vonoprazan was used as initial therapy in 6 and as maintenance therapy in 4. Adverse event rates were similar for vonoprazan and proton-pump inhibitors (PPIs).

Conclusions

Our findings suggest that vonoprazan is a safe option for the management of erosive oesophagitis, gastric/peptic ulcers, or peptic ulcers induced by chronic use of aspirin or NSAIDs.

Evidence-based clinical practice guidelines for gastroesophageal reflux disease 2021

In Japan, with the increasing prevalence of gastroesophageal reflux disease (GERD) and growing public interest, the Japanese Society of Gastroenterology issued Evidence-based Clinical Practice Guidelines for GERD (1st edition) in 2009 and a revised 2nd edition in 2015. A number of studies on GERD were subsequently conducted in Japan and abroad, and vonoprazan, a potassium-competitive acid blocker (P-CAB), became available for the first time in Japan in February 2015. The revised 3rd edition (Japanese edition), which incorporates new findings and information, was published in April 2021. These guidelines are summarized herein, particularly sections related to the treatment of GERD. The important clinical issues addressed in the present revision are (i) the introduction of treatment algorithms that classify GERD into reflux esophagitis and non-erosive reflux disease, (ii) the clarification of treatment algorithms based on to the severity of reflux esophagitis, and (iii) the positioning of vonoprazan in the treatment for GERD. The present guidelines propose vonoprazan as the initial/maintenance treatment for severe reflux esophagitis. They also recommend vonoprazan or PPI as an initial treatment for mild reflux esophagitis and recommended PPI and proposed vonoprazan as maintenance treatment. These updated guidelines offer the best clinical strategies for GERD patients in Japan and hope that they will be of global use for the diagnosis and treatment for GERD.

Vonoprazan versus proton pump inhibitors for postendoscopic submucosal dissection bleeding in the stomach: a multicenter population-based comparative study

BACKGROUND AND AIMS

The effectiveness of vonoprazan relative to that of proton pump inhibitors (PPIs) after gastric endoscopic submucosal dissection (ESD) is unclear. Although previous studies used post-ESD ulcer healing as the outcome measure, post-ESD bleeding rate is the most objective and appropriate outcome measure because it has less ascertainment bias. We aimed to compare the post-ESD bleeding rates between vonoprazan and PPIs.

METHODS

This nationwide population-based retrospective cohort study was conducted between 2014 and 2018 and involved 9 hospitals. After 2 days of intravenous PPI administration, either vonoprazan or PPI was administrated from postoperative day 2 to 30.

RESULTS

Overall, data of 1715 patients (627 patient pairs) were analyzed through propensity score matching. The vonoprazan group had significantly lower post-ESD bleeding rates than the PPI group (overall, 11.9% vs 17.2%, P = .008; bleeding between days 2 and 30, 7.8% vs 11.8%, P = .015). The readmission rate because of post-ESD bleeding was lower in the vonoprazan group (2.4% vs 4.1%, P = .081). Blood transfusion (2.1% vs 3.0%, P = .15) and additional surgery because of delayed perforation (.5% vs 1.0%, P = .32) were not significantly different between the 2 groups. No deaths within 30 days occurred in both groups. On Cox regression analysis, vonoprazan use, lesion location (antrum), aspirin use, direct oral anticoagulant use, and Charlson Comorbidity Index (≥2) were associated with an increased risk of post-ESD bleeding within 30 days.

CONCLUSIONS

Vonoprazan has a lower post-ESD bleeding rate than PPIs. Further prospective studies are required to confirm these results.

Randomized clinical trial: 7-day vonoprazan-based versus 14-day omeprazole-based triple therapy for Helicobacter pylori

BACKGROUND AND AIM

Vonoprazan has more potent and sustained acid inhibitory effects than proton pump inhibitors; therefore, Helicobacter pylori eradication rates are expected to improve with the use of vonoprazan-based regimens. To date, no randomized trial has compared the efficacy of 7-day vonoprazan-based triple therapy (7-VAC) with 14-day omeprazole-based triple therapy (14-OAC). This study aimed to compare the H. pylori eradication rates of 7-VAC and 14-OAC.

METHODS

This randomized clinical trial was performed at a tertiary hospital in Bangkok. Patients with active H. pylori infection who were naive to treatment were included and randomized (1:1) into either a 7-VAC group (vonoprazan 20 mg bid. pc., amoxicillin 1000 mg bid. pc., and clarithromycin 500 mg bid. pc.) or a 14-OAC group (omeprazole 20 mg bid. ac., amoxicillin 1000 mg bid. pc., and clarithromycin 500 mg bid. pc.). Eradication success was evaluated by urea breath test 4-6 weeks after completion of treatment.

RESULTS

A total of 122 subjects were randomized to receive 7-VAC (n = 61) or 14-OAC (n = 61). The H. pylori eradication rates of the 7-VAC and 14-OAC groups were 96.7% and 88.5% (P = 0.083), respectively, by intention-to-treat analysis and 98.3% and 93.1% (P = 0.159), respectively, by per-protocol analysis. All treatment-related adverse events were mild and not significantly different between the two groups. Common side effects included bitter taste, nausea, and dizziness.

CONCLUSIONS

The 7-VAC regimen was well tolerated and achieved similar eradication rates and side effects to those of 14-OAC; therefore, 7-VAC may be considered an alternative regimen for H. pylori treatment with the benefit of shorter duration.

Vonoprazan for treatment of gastroesophageal reflux disease: Research advances

Gastroesophageal reflux disease is a common gastrointestinal disease that can be effectively treated by drugs alone. Proton pump inhibitors are the currently mainstay drugs for the treatment of gastroesophageal reflux disease, but are insufficiently effective. Vonoprazan, which is a new type of drug that inhibits gastric acid secretion, has been employed for the management of gastroesophageal reflux disease. In this article, we comprehensively review the current evidence regarding clinical efficacy and safety of vonoprazan for the treatment of gastroesophageal reflux disease to guide the clinical decision.

The Effect of Food on the Pharmacokinetics of the Potassium-Competitive Acid Blocker Vonoprazan

Herein, we report a food‐effect study of vonoprazan, an oral potassium‐competitive acid blocker. In a phase 1, randomized, open‐label, crossover study, healthy subjects received a single 20‐mg dose of vonoprazan either following an overnight fast or 30 minutes after a high‐fat breakfast. Plasma vonoprazan levels were determined at 0 hour and at 17 subsequent assessment points up to 48 hours after dosing. After a 5‐day washout, subjects received a second 20‐mg vonoprazan dose in the alternative fed/fasted state (identical process repeated). Twenty‐four subjects completed the study. Vonoprazan exposure was not meaningfully affected by food. Geometric mean ratios for maximum concentration, area under the concentration‐time curve from time 0 to 24 hours, and area under the plasma concentration–time curve extrapolated to infinity obtained under fed and fasting conditions were 1.05 (90% confidence interval, 0.98‐1.12), 1.13 (1.09‐1.18), and 1.15 (1.11‐1.19), respectively. Four subjects experienced 6 adverse events that were all mild and considered unrelated to the study drug. Vonoprazan can be administered without regard to food intake.

Clinical Outcomes of Vonoprazan-Treated Patients after Endoscopic Submucosal Dissection for Gastric Neoplasms: A Prospective Multicenter Observation Study

BACKGROUND

Vonoprazan (VPZ) has the potential to prevent delayed bleeding and promote ulcer healing after endoscopic submucosal dissection (ESD) similar to proton pump inhibitors (PPIs).

OBJECTIVE

We aimed to evaluate the outcomes of VPZ-treated patients after ESD and compared the efficacy and feasibility in preventing a delayed bleeding and in healing an artificial ulcer after ESD between the VPZ and PPI therapies.

METHODS

This was a prospective, observation study in 11 Japanese medical institutions. We enrolled and evaluated 223 patients who underwent gastric ESD followed by VPZ treatment (VPZ group). We selected 385 patients who underwent gastric ESD followed by PPI treatment as historical controls (PPI group) to compare the outcomes between the VPZ and PPI groups using a propensity score matching analysis.

RESULTS

Among the 223 patients treated with VPZ, 173 were men and 50 were women with a median age of 72 years and with a median tumor size of 12.0 mm. Rates of en bloc resection and complete resection were 99.1 and 94.2%, respectively. Lymphovascular invasion was found in 6 (6.3%) cases. Intraoperative perforation and delayed bleeding occurred in 3 (1.3%) and 10 patients (4.5%), respectively. Scarring of artificial post-ESD ulcer was found in 153 patients (68.6%) at 6 weeks after ESD. The 205 pairs of propensity score-matched patients were comparable between the VPZ and PPI groups. The rate of delayed bleeding in the VPZ and PPI groups was 3.9 and 4.4%, respectively (difference, 0.5 percentage points; 95% confidence interval, -3.7 to 2.8%; non-inferiority, p = 0.01). Therefore, VPZ therapy demonstrated non-inferiority against PPI therapy in reducing the rate of delayed bleeding. The scar-stage ulcer at 6 weeks in the VPZ group and 8 weeks in the PPI group was 68.3 and 74.6%, respectively (p = 0.19).

CONCLUSIONS

VPZ therapy showed an efficacy and feasibility in preventing a delayed bleeding after ESD similar to the PPI therapy. VPZ for 6 weeks and PPI for 8 weeks were similarly effective for an artificial ulcer healing after ESD.

Reliability of self-reported questionnaire for epidemiological investigation of Helicobacter pylori eradication in a population-based cohort study

General population-based cohort studies provide solid evidence on mass Helicobacter pylori (HP) eradication effects. Self-reported questionnaires are occasionally used in such studies to ascertain the HP eradication history. However, reports on the reliability of these questionnaires are lacking. This general population-based cohort study included 899 individuals with HP infection at the baseline survey who were reported to have eradicated it at the 5-year follow-up survey. Of these, the medical records of 280 patients were available for investigation, and the HP eradication status of 93 individuals was ascertained. Their medical records were reviewed, and the reliability of the self-reported questionnaire responses was assessed. Of the 91 individuals who successfully eradicated HP based on the medical records, 90 (98.9%) answered the self-reported questionnaire correctly, with an unweighted kappa value of 0.661 (p < 0.001). The difference between the self-reported and medical records age at eradication was within a 1-year range in most participants (86.8%). Similarly, the HP eradication procedure and the outcomes were reasonably matched. In conclusion, the responses to the self-reported HP eradication questionnaire were almost consistent with the medical records. Thus, HP eradication history assessment by a self-reported questionnaire is reliable for an epidemiological study in the general population.

Efficacy of vonoprazan 10 mg compared with 20 mg for the initial treatment in patients with erosive esophagitis: a randomized pilot study

BACKGROUND

The study aimed to investigate the efficacy of vonoprazan 10 mg compared with 20 mg in patients with erosive esophagitis.

METHOD

Seventy-three patients with erosive esophagitis were randomly divided into two groups either vonoprazan 20 mg (n = 37) or 10 mg (n = 36). They were administered each dose for 4 weeks as the initial treatment followed by maintenance treatment with 10 mg for 8 weeks. The primary endpoints were mucosal healing rate and symptom relief at 4 weeks. The secondary endpoint was symptom relief at 12 weeks after the maintenance treatment. Mucosal healing was assessed endoscopically, and symptom relief was assessed using the FSSG score.

RESULTS

At 4 weeks, the endoscopic healing rates of the 20 mg and 10 mg groups were 94.6% and 94.4%, respectively. The FSSG scores of the 20 mg and 10 mg groups were significantly decreased in both treatment groups from 13 (4-39) to 4 (0-25) and 14 (4-40) to 3 (0-29), respectively. At 12 weeks, the scores further decreased to 2 (0-13) and 2 (0-26), respectively. The vonoprazan 10 mg group showed a similar therapeutic effect to the 20 mg group in mucosal healing at 4 weeks and in symptom relief throughout the study period. When stratified by esophagitis grading, these findings were still demonstrated in grade A/B patients but not in grade C/D patients.

CONCLUSION

Our findings suggest that initial treatment with vonoprazan 10 mg might be useful especially in patients with mild erosive esophagitis. Large controlled studies are warranted to confirm our investigation.

Effects of pirenzepine on vonoprazan-induced gastric acid inhibition and hypergastrinemia

BACKGROUND

Compared to proton pump inhibitors, vonoprazan exerts a greater inhibitory effect on gastric acid secretion and is useful for treating acid-related diseases, such as gastro-esophageal reflux disease. However, there is a problem that vonoprazan causes hypergastrinemia, which confers a risk of carcinoid tumor. A previous report demonstrated that pirenzepine, an M1 muscarinic receptor antagonist, enhances the acid inhibitory effects while suppressing hypergastrinemia induced by omeprazole. Here, we examined whether pirenzepine enhances the gastric acid inhibitory effects of vonoprazan without further increasing serum gastrin levels.

METHODS

Eleven healthy volunteers were subjected to 24-h intragastric pH monitoring and serum gastrin measurements on day 7 of three different regimens: pirenzepine 75 mg alone, vonoprazan 10 mg alone, and vonoprazan 10 mg plus pirenzepine 75 mg administered in a randomized crossover fashion.

RESULTS

Median pH 4 holding time ratios (range) achieved with pirenzepine 75 mg, vonoprazan 10 mg, and vonoprazan 10 mg plus pirenzepine 75 mg were 6.9% (2.4-32.8%), 88.4% (54.6-100%), and 84.2% (40.3-100%), respectively. Respective serum gastrin levels were 79 (75-210) pg/ml, 310 (110-870) pg/ml, and 170 (140-930) pg/ml. In cases with hypergastrinemia (gastrin ≥ 200 pg/ml) induced by vonoprazan 10 mg alone, concomitant treatment with pirenzepine significantly reduced serum gastrin levels from 370 to 180 pg/ml (P = 0.028).

CONCLUSION

Although pirenzepine does not enhance acid inhibition, it does improve hypergastrinemia induced by vonoprazan to some extent.

Is a Potassium-Competitive Acid Blocker Truly Superior to Proton Pump Inhibitors in Terms of Helicobacter pylori Eradication?

Vonoprazan (VPZ), a new potassium-competitive acid blocker, has been approved and used for Helicobacterpylori eradication in Japan. To date, many studies, as well as several systematic reviews and meta-analyses (MAs), have compared VPZ-based 7-day triple therapy with proton pump inhibitor (PPI)-based therapy. An MA of randomized controlled trials (RCTs) comparing first-line VPZ- with PPI-based triple therapy, the latter featuring amoxicillin (AMPC) and clarithromycin (CAM), found that approximately 30% of patients hosted CAM-resistant H. pylori; however, the reliability was poor because of high heterogeneity and a risk of selection bias. VPZ-based triple therapy is superior to PPI-based triple therapy for patients with CAM-resistant H. pylori, but not for those with CAM-susceptible H. pylori. An MA of non-RCTs found that second-line VPZ-based triple therapies were slightly (~2.6%) better than PPI-based triple therapies (with AMPC and metronidazole). However, the reliability of that MA was also low because of selection bias, confounding variables and a risk of publication bias; in addition, it is difficult to generalize the results because of a lack of data on antibiotic resistance. VPZ-based triple therapy (involving AMPC and sitafloxacin) was more effective than PPI-based triple therapy in a third-line setting, but a confirmatory RCT is needed. Non-RCT studies indicated that VPZ-based triple therapy involving CAM and metronidazole may be promising. Any further RCTs must explore the antibiotic-resistance status when evaluating the possible superiority of a potassium-competitive acid blocker.

Prevalence of behavioral disorders in patients with vonoprazan-refractory reflux symptoms

BACKGROUND

Behavioral disorders, such as supragastric belching (SGB) and rumination syndrome (RS), which may be treated by cognitive behavioral therapy, are common in patients with reflux symptoms refractory to proton pump inhibitors (PPI). Vonoprazan (VPZ) has been used as a new type of acid inhibitor in Japan since 2015. We herein investigated the prevalence of behavioral disorders in patients with VPZ-refractory reflux symptoms and attempted to identify predictive factors.

METHODS

We retrospectively analyzed esophagogastroduodenograms, high-resolution manometry, and 24-h multiluminal impedance pH-metry (MIIpH) in patients with VPZ-refractory reflux symptoms (heartburn or regurgitation) receiving 20 mg VPZ who underwent these tests at our hospital between January 2015 and April 2020. Patients were divided as follows: non-erosive reflux disease with pathological esophageal acid exposure (NERD), functional heartburn (FH), reflux hypersensitivity (RH), excessive (> 13 per day) SGB, and possible RS based on MIIpH parameters.

RESULTS

Among 49 patients, 6 (12.2%) had SGB, 4 (8.2%) possible RS, 29 (59.2%) FH, 9 (18.4%) RH, and 1 (2%) NERD. Possible RS patients had more postprandial non-acid reflux events than FH patients (p < 0.05). The multivariate logistic regression analysis did not identify any predictive factors with statistical significance.

CONCLUSION

More than 20% patients with VPZ-refractory reflux symptoms had behavioral disorders. The use of HRM and MIIpH may be clinically relevant for a better diagnosis and more specific treatment.

High-dose dual therapy versus bismuth-containing quadruple therapy for the treatment of Helicobacter pylori infection – A review of the strengths, weaknesses, and proposed solutions

Helicobacter pylori is the principal cause of peptic ulcers, gastric cancer, and mucosa-associated lymphoid tissue lymphoma. The first treatment to H. pylori infection is dual therapy (a bismuth compound plus metronidazole). On the launch of omeprazole in 1988, dual therapy became omeprazole and amoxicillin (low dose). The poor H. pylori eradication rates by either bismuth-based or low-dose dual therapy drove more combinations of antibiotics were needed. Antibiotic resistance, especially clarithromycin and metronidazole, has made bismuth-containing quadruple therapy (BCQT) a savior for first-line and second-line treatments. However, its complicated dosing regimen commonly causes more adverse events and poor drug compliance. Thus, high-dose dual therapy (HDDT) has been re-arising. This article reviews the strengths and weaknesses of HDDT versus BCQT with proposed solutions.

Safety, Tolerability and Pharmacokinetics of Single Ascending and Multiple Oral Doses of Tegoprazan in Healthy Chinese Subjects

BACKGROUND AND OBJECTIVES

Tegoprazan is one of the potassium-competitive acid blockers (P-CABs). It exhibits its anti-secretory effects by competitively and reversibly blocking the availability of K⁺ of the H⁺, K⁺-ATPase. This study was designed to investigate the safety and pharmacokinetics of tegoprazan in healthy Chinese subjects.

METHODS

Thirty-eight healthy Chinese subjects were recruited in this randomized, single-center, double-blind, placebo-controlled study, with a single ascending dose of 50, 100, 200 mg and a multiple dose of 100 mg for 10 days. The plasma concentration of tegoprazan was determined by a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method. Pharmacokinetics were evaluated via non-compartmental and compartmental model analysis. Safety was assessed by physical examinations, vital signs, clinical laboratory tests, and electrocardiograms.

RESULTS

No serious adverse event was observed in this study. After single-dose administration (50, 100 and 200 mg), tegoprazan was rapidly absorbed with a median maximum measure plasma concentration (T_max) at 0.5 h and declined with a terminal (elimination) half-life (t_1/2) of 3.87-4.57 h. The maximum measured plasma concentration (C_max) for tegoprazan was 813.80, 1494.60 and 2829.00 ng/mL. Meanwhile, the corresponding area under the concentration-time curve (AUC) from time zero to infinity (AUC_0-inf) was 2761.00, 5980.05 and 11,044.72 ng∙h/mL in 50, 100, 200 mg group, respectively. Dose-dependent increase was observed in the value of C_max and AUC after administration of tegoprazan 50 to 200 mg. The two-compartment model well described the pharmacokinetic profile of tegoprazan. In the steady state, no accumulation was found after repeated administration at the 100-mg dose level. No experimental differences were found based on gender.

CONCLUSIONS

Tegoprazan was well tolerated in the dose range of 50-200 mg in single- and 100 mg in multiple-dose studies. Tegoprazan shows dose linearity with oral administration after a single dose of 50 to 200 mg and less drug accumulation after 10 days of continuous administration in 100 mg.

Use of vonoprazan for management of systemic sclerosis-related gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) in systemic sclerosis (SSc) can significantly reduce a patient's quality of life. GERD in SSc is occasionally resistant to conventional anti-acid treatment. Vonoprazan is an H⁺/K⁺-ATPase blocker that is approved in Japan for treatment of GERD. The aim of the present study was to evaluate the efficacy of vonoprazan in SSc-related GERD. The frequency scale for symptoms of GERD (FSSG) scores were collected before and after vonoprazan treatment in 15 SSc patients with GERD. Additionally, endoscopic esophagogastroduodenoscopy was performed in select patients. Conventional proton pump inhibitors or histamine-2 receptor antagonists had been previously administered in 93% (14/15) of the patients. Although the baseline esophagogastroduodenoscopy examination did not show severe erosion in the majority of patients, the mean total FSSG score before vonoprazan treatment was notably high (25.2±10.7) compared to a normal score of <8. After vonoprazan treatment, the FSSG score decreased to 9.6±7.0. The mean improvement rate of the total FSSG, acid reflux and dysmotility scores were 60.8±21.2% (P=0.0004), 67.3±24.8% (P<0.0001) and 55.4±26.0% (P=0.0022), respectively. These results suggest that vonoprazan may be a potentially effective treatment for GERD in patients with SSc.

Effects of vonoprazan on gastric PH and clinical course after gastric ESD: A retrospective and prospective study

Background

Vonoprazan has been more widely used for artificial ulcers after endoscopic submucosal dissection (ESD) for early gastric cancer; however, no reports have examined intragastric pH during ESD. The present study aimed to measure gastric pH at the time of ESD and the clinical course afterwards for patients treated with vonoprazan the night before undergoing ESD.

Materials and methods

We examined medication status regarding gastric acid secretion and antithrombotic drugs, post-ESD bleeding as a perioperative complication, and the timing of upper gastrointestinal endoscopy after ESD and ulcer healing in 156 patients who underwent gastric ESD at our hospital from January 2014 to December 2019. The gastric pH was measured at the time of ESD after administration of 20 mg vonoprazan on the night before gastric ESD.

Results

There were 14 cases of post-ESD bleeding in patients treated with proton-pump inhibitors (PPIs), including oozing during second-look endoscopy compared to only 1 case of bleeding with vonoprazan administration (p < 0.05). Vonoprazan was also associated with better post-ESD ulcer healing than PPIs. Gastric pH during ESD after vonoprazan administration on the night before gastric ESD was ≥6.96 in all 11 patients.

Conclusion

Post-ESD bleeding was reduced, and ulcer healing was improved in patients treated with vonoprazan the night before their procedure. Our results suggest high gastric pH during ESD due to vonoprazan administration may be beneficial for hemostasis and ulcer healing following ESD.

Lack of significant differences between gastrointestinal tract microbial population structure of Helicobacter pylori-infected subjects before and 2 years after a single eradication event

BACKGROUND

According to recent estimates 80% of Latvian population is infected with Helicobacter pylori thus their susceptibility to numerous gastric tract diseases is increased. The 1^st line H. pylori eradication therapy includes treatment with clarithromycin in combination with amoxicillin or metronidazole and a proton pump inhibitor. However, potential adverse events caused by such therapies to microbiome are insufficiently studied.

OBJECTIVE

This study aimed to evaluate the long-term effect of H. pylori eradication on human gastrointestinal tract (GIT) microbiome.

METHODS

The assessment of H pylori eradication impact on GIT microbiome was done by analyzing 120 samples acquired from 60 subjects. Each individual was prescribed the following 10-day eradication regimen: Esomeprazolum 40 mg, Clarithromycinum 500 mg, and Amoxicillinum 1000 mg, BID. Samples from each individual were collected before starting H pylori eradication therapy, and 2 years after the completion of the therapy in OC-Sensor (Eiken Chemical Co.) sample collection containers and stored at -86°C. Prior to DNA extraction, the samples were lyophilized, and total DNA was extracted using FastDNA Spin Kit for Soil. 16S V3 rRNA gene sequencing was done employing Ion Torrent PGM, and the obtained raw sequences were analyzed using vsearch and R (phyloseq, cluster packages).

RESULTS

Alpha diversity measurements-observed OTUs, Chao1 and Shannon index did not differ significantly between the pre- and post-eradication states (two-tailed paired t test: P = .95; P = .71, P = .24, respectively). Unweighted and weighted UniFrac distances of beta diversity analysis indicated a non-specific pattern of sample clustering. Enterotype shift was observed for the majority of individuals comparing pre- and post-eradication study groups. Association analysis revealed that certain bacterial genera significantly correlated with age (eg, Dialister, Paraprevotella, Bifidobacterium), individual (eg, Thermotunica, Streptomyces, Faecalibacterium), and history of respiratory and/or allergic diseases (eg, Colinsella, Faecalibacterium). Redundancy analysis confirmed that the individual was a significant determinant of the subject's microbial community composition (ANOVA, 999 perm., P = .001) with the further lower impact of subject-specific medical history (eg, medication used as prescribed: P = .005, history of cardiovascular diseases: P = .005, history of respiratory, and/or allergic diseases: P = .015) and physiological (eg, age: P = .005, gender: P = .02) parameters. In the post-eradication study group, number of influential genera (n = 260) was increased compared to the pre-eradication study group (n = 209).

CONCLUSION

Modest global differences at the community level exist between individuals before and after the eradication therapy; however, the microbiome structure is more related to the subject-specific parameters rather than by the eradication therapy itself.

The Potential Benefits of Vonoprazan as Helicobacter pylori Infection Therapy

Helicobacter pylori infection is a severe global health problem that is closely associated with acid-related diseases and gastric malignancies. Eradicating H. pylori is strongly recommended for lowering peptic ulcer recurrence and preventing gastric cancer. The current approved H. pylori eradication regimen combines a proton pump inhibitor (PPI) with two antibiotics. Unfortunately, this regimen failed to meet expectations mostly due to antibiotic resistance and insufficient gastric acid suppression. Vonoprazan, a novel potassium-competitive acid blocker, showed promising results as a PPI replacement. Vonoprazan inhibits gastric acid secretion by acting as a reversible competitive inhibitor against potassium ions and forming disulfide bonds with the cysteine molecule of H⁺/K⁺-ATPase. Vonoprazan has superior pharmacological characteristics over PPI, such as no requirement for acid activation, stability in acidic conditions, shorter optimum acid suppression period, and resistance to cytochrome P (CYP)2C19 polymorphism. Several comparative randomized controlled trials and meta-analyses revealed the superiority of vonoprazan in eradicating H. pylori, notably the resistant strains. The adverse effect caused by vonoprazan is long-term acid suppression that may induce elevated gastrin serum, hypochlorhydria, and malabsorption. All vonoprazan studies have only been conducted in Japan. Further studies outside Japan are necessary for universally conclusive results.

Pharmacologic treatment of GERD: Where we are now, and where are we going?

The introduction of acid inhibition in clinical practice has revolutionized the management of acid-related diseases, leading to the virtual abolition of elective surgery for ulcer disease and relegating antireflux surgery to patients with gastroesophageal reflux disease (GERD) not adequately managed by medical therapy. Proton pump inhibitors (PPIs) are the antisecretory drugs of choice for the treatment of reflux disease. However, these drugs still leave some unmet clinical needs in GERD. PPI-refractoriness is common, and persistent symptoms are observed in up to 40-55% of daily PPI users. Potassium-competitive acid blockers (P-CABs) clearly overcome many of the drawbacks and limitations of PPIs, achieving rapid, potent, and prolonged acid suppression, offering the opportunity to address many of the unmet needs. In recent years, it has been increasingly recognized that impaired mucosal integrity is involved in the pathogenesis of GERD. As a consequence, esophageal mucosal protection has emerged as a new, promising therapeutic avenue. When P-CABS are used as add-on medications to standard treatment, a growing body of evidence suggests a significant additional benefit, especially in the relief of symptoms not responding to PPI therapy. On the contrary, reflux inhibitors are considered a promise unfulfilled, and prokinetic agents should only be used on a case-by-case basis.

The pharmacotherapeutic management of gastroesophageal reflux disease (GERD)

INTRODUCTION

Gastroesophageal reflux disease (GERD) is a very common worldwide condition, affecting about 15-20% of the whole population, and representing a major burden for health-care systems. Because of its frequency, health physicians - family doctors as well as specialists - should be aware of the different pharmacotherapeutic approaches in managing GERD, according to disease severity.

AREAS COVERED

Authors summarize the pharmacological management of GERD in adults, present the different pharmaceutical classes, and review the evidence on efficacy for each treatment according to the most common clinical scenarios: non-erosive gastroesophageal reflux disease (NERD), erosive esophagitis (EE), and proton-pump inhibitor (PPI) refractory GERD. They also provide an overview of treatments under development.

EXPERT OPINION

To date, PPIs remain the most effective treatment option for both NERD and EE. However, Potassium-Competitive Acid blockers (PCAB) may be considered, with at least similar efficacy in Asian populations. Preliminary data suggest that PCABs could be superior to classic PPIs in patients with severe EE, and may also be of particular interest in the management of PPI-refractory GERD patients. Their definitive role in GERD management, however, still remains to be determined based on properly designed and conducted randomized clinical trials.

Feasibility of gastric endoscopic submucosal dissection without using proton pump inhibitor injection: a propensity score analysis

Purpose: Endoscopic submucosal dissection is a promising method for the resection of superficial gastric neoplasms. To date, several institutions have used proton pump inhibitor injections over the perioperative period. However, there is very little evidence regarding their efficacy. To overcome this limitation, we compared procedural outcomes and the prevention of adverse events of proton pump inhibitor injection with an orally administered active potassium-competitive acid blocker alone. Participants and Methods: We enrolled a total of 150 patients treated for superficial gastric neoplasms at a single institution between April 2015 and December 2018. Patients treated for 2 days with proton pump inhibitor injections following 12 days of oral potassium-competitive acid blocker (proton pump inhibitor group=80) were compared with patients treated for 14 days orally with potassium-competitive acid blocker alone (potassium-competitive acid blocker group=70) using propensity score analysis. We evaluated intragastric pH levels prior to endoscopic submucosal dissection, frequency of intraoperative major bleeding, procedure time, en bloc resection rate, curability, ulcer reduction rate 14 days after endoscopic submucosal dissection, and adverse events (including perforation and postoperative bleeding). Results: Propensity score analysis yielded 43 matched pairs. The comparison demonstrated similar values for the outcomes. For all cases, we observed intragastric pH levels >6.4 prior to endoscopic submucosal dissection. Postoperative bleeding rates were 2.3% (1/43) in the proton pump inhibitor group and 0.0% (0/43) in the potassium-competitive acid blocker group (P=0.315). Conclusions: Oral potassium-competitive acid blocker alone was as effective as proton pump inhibitor injection, with a low incidence of adverse events. Based on these results, proton pump inhibitor injection might be omitted during gastric endoscopic submucosal dissection.

Seven-day vonoprazan and low-dose amoxicillin dual therapy as first-line Helicobacter pylori treatment: a multicentre randomised trial in Japan

OBJECTIVE

To date, no randomised trials have compared the efficacy of vonoprazan and amoxicillin dual therapy with other standard regimens for Helicobacter pylori treatment. This study aimed to investigate the efficacy of the 7-day vonoprazan and low-dose amoxicillin dual therapy as a first-line H. pylori treatment, and compared this with vonoprazan-based triple therapy.

DESIGN

This prospective, randomised clinical trial was performed at seven Japanese institutions. Patients with H. pylori-positive culture test and naive to treatment were randomly assigned in a 1:1 ratio to either VA-dual therapy (vonoprazan 20 mg+amoxicillin 750 mg twice/day) or VAC-triple therapy (vonoprazan 20 mg+amoxicillin 750 mg+clarithromycin 200 mg twice/day) for 7 days, with stratification by age, sex, H. pylori antimicrobial resistance and institution. Eradication success was evaluated by ¹³C-urea breath test at least 4 weeks after treatment.

RESULTS

Between October 2018 and June 2019, 629 subjects were screened and 335 were randomised. The eradication rates of VA-dual and VAC-triple therapies were 84.5% and 89.2% (p=0.203) by intention-to-treat analysis, respectively, and 87.1% and 90.2% (p=0.372) by per-protocol analysis, respectively. VA-dual was non-inferior to VAC-triple in the per-protocol analysis. The eradication rates in strains resistant to clarithromycin for VA-dual were significantly higher than those for VAC-triple (92.3% vs 76.2%; p=0.048). The incidence of adverse events was equal between groups.

CONCLUSION

The 7-day vonoprazan and low-dose amoxicillin dual therapy provided acceptable H. pylori eradication rates and a similar effect to vonoprazan-based triple therapy in regions with high clarithromycin resistance.

TRIAL REGISTRATION NUMBER

UMIN000034140.

Physiologically based pharmacokinetic-pharmacodynamic modeling for prediction of vonoprazan pharmacokinetics and its inhibition on gastric acid secretion following intravenous/oral administration to rats, dogs and humans

Vonoprazan is characterized as having a long-lasting antisecretory effect on gastric acid. In this study we developed a physiologically based pharmacokinetic (PBPK)-pharmacodynamic (PD) model linking to stomach to simultaneously predict vonoprazan pharmacokinetics and its antisecretory effects following administration to rats, dogs, and humans based on in vitro parameters. The vonoprazan disposition in the stomach was illustrated using a limited-membrane model. In vitro metabolic and transport parameters were derived from hepatic microsomes and Caco-2 cells, respectively. We found the most predicted plasma concentrations and pharmacokinetic parameters of vonoprazan in rats, dogs and humans were within twofold errors of the observed data. Free vonoprazan concentrations (f_u × C₂) in the stomach were simulated and linked to the antisecretory effects of the drug (I) (increases in pH or acid output) using the fomula dI/dt = k × f_u × C₂ × (I_max − I) − k_d × I. The vonoprazan dissociation rate constant k_d (0.00246 min⁻¹) and inhibition index K_I (35 nM) for H⁺/K⁺-ATPase were obtained from literatures. The vonoprazan-H⁺/K⁺-ATPase binding rate constant k was 0.07028 min⁻¹· μM⁻¹ using ratio of k_d to K_I. The predicted antisecretory effects were consistent with the observations following intravenous administration to rats (0.7 and 1.0 mg/kg), oral administration to dogs (0.3 and 1.0 mg/kg) and oral single dose or multidose to humans (20, 30, and 40 mg). Simulations showed that vonoprazan concentrations in stomach were 1000-fold higher than those in the plasma at 24 h following administration to human. Vonoprazan pharmacokinetics and its antisecretory effects may be predicted from in vitro data using the PBPK-PD model of the stomach. These findings may highlight 24-h antisecretory effects of vonoprazan in humans following single-dose or the sustained inhibition throughout each 24-h dosing interval during multidose administration.

Simultaneous determination of Rivaroxaban and TAK-438 in rat plasma by LC-MS/MS: application to pharmacokinetic interaction study

Aim: A sensitive and reliable LC-MS/MS method has been established and validated to the quantitation of rivaroxaban (RIV) and TAK-438 in rat plasma using carbamazepine as internal standard. Results: The procedure of method validation was conducted according to the guidelines of EMA and US FDA. At the same time, the method was applied to pharmacokinetic interactions study between RIV and TAK-438 for the first time. When RIV and TAK-438 co-administration to rats, main pharmacokinetic parameters of TAK-438 like AUC_(0-t), AUC_(0-∞) and C_max had statistically significant increase. The main pharmacokinetic parameters of RIV have no statistically significant difference (p > 0.05) when co-administered except for t_1/2 (p < 0.01). Conclusion: The results indicated that drug-drug interactions occurred between RIV and TAK-438 when co-administered to rats.

Chemoprevention of gastric cancer development after Helicobacter pylori eradication therapy in an East Asian population: Meta-analysis

BACKGROUND

Helicobacter pylori (H. pylori) infection is a risk factor for gastric cancer (GC), especially in East Asian populations. Most East Asian populations infected with H. pylori are at higher risk for GC than H. pylori-positive European and United States populations. H. pylori eradication therapy reduces gastric cancer risk in patients after endoscopic and operative resection for GC, as well as in non-GC patients with atrophic gastritis.

AIM

To clarify the chemopreventive effects of H. pylori eradication therapy in an East Asian population with a high incidence of GC.

METHODS

PubMed and the Cochrane library were searched for randomized control trials (RCTs) and cohort studies published in English up to March 2019. Subgroup analyses were conducted with regard to study designs (i.e., RCTs or cohort studies), country where the study was conducted (i.e., Japan, China, and South Korea), and observation periods (i.e., ≤ 5 years and > 5 years). The heterogeneity and publication bias were also measured.

RESULTS

For non-GC patients with atrophic gastritis and patients after resection for GC, 4 and 4 RCTs and 12 and 18 cohort studies were included, respectively. In RCTs, the median incidence of GC for the untreated control groups and the treatment groups was 272.7 (180.4–322.4) and 162.3 (72.5–588.2) per 100000 person-years in non-GC cases with atrophic gastritis and 1790.7 (406.5–2941.2) and 1126.2 (678.7–1223.1) per 100000 person-years in cases of after resection for GC. Compared with non-treated H. pylori-positive controls, the eradication groups had a significantly reduced risk of GC, with a relative risk of 0.67 [95% confidence interval (CI): 0.47–0.96] for non-GC patients with atrophic gastritis and 0.51 (0.36–0.73) for patients after resection for GC in the RCTs, and 0.39 (0.30–0.51) for patients with gastritis and 0.54 (0.44–0.67) for patients after resection in cohort studies.

CONCLUSION

In the East Asian population with a high risk of GC, H. pylori eradication effectively reduced the risk of GC, irrespective of past history of previous cancer.

Efficacy of vonoprazan for the prevention of bleeding after gastric endoscopic submucosal dissection with continuous use of antiplatelet agents

Background  Post-procedural bleeding, after gastric endoscopic submucosal dissection (ESD) for high risk thromboembolic cases that require continuous antiplatelet therapy, is challenging. Its incidence rate is > 20 % among those using conventional antacids. We evaluated the efficacy of perioperative management with vonoprazan to prevent post-ESD bleeding. Materials and methods  This was a multicenter prospective interventional trial conducted at 10 Japanese referral centers. Patients who regularly used antiplatelet agents (aspirin or thienopyridine derivatives, etc.) and who required continuous antithrombotic medication due to high thromboembolic risk were enrolled. They underwent gastric ESD with continuous aspirin therapy. Oral administration of vonoprazan (20 mg daily) was started from the day of ESD and continued for 28 days. The primary end point was the incidence of post-ESD bleeding. The sample size was 50 patients, and vonoprazan was considered to be effective when the upper threshold of the 95 % confidence interval (CI) for post-ESD bleeding did not exceed 20 %. Results  Although 50 patients were enrolled, one patient withdrew consent. Therefore, 49 patients were included in the analysis. One patient who used aspirin and clopidogrel experienced bleeding 11 days after ESD. The overall post-ESD bleeding rate was 2.0 % (1/49; 95 %CI 0.4-10.7 %). Thromboembolic events were not observed. One case of ESD-associated adverse events (perforation) and one case of drug-associated adverse events (drug eruption, possibly due to vonoprazan) were observed. Conclusions  Vonoprazan may be efficacious for preventing post-ESD bleeding in patients using continuous antiplatelet therapy, warranting further comparative study to definitively test the effectiveness of the drug.

The Physiology of the Gastric Parietal Cell

Parietal cells are responsible for gastric acid secretion, which aids in the digestion of food, absorption of minerals, and control of harmful bacteria. However, a fine balance of activators and inhibitors of parietal cell-mediated acid secretion is required to ensure proper digestion of food, while preventing damage to the gastric and duodenal mucosa. As a result, parietal cell secretion is highly regulated through numerous mechanisms including the vagus nerve, gastrin, histamine, ghrelin, somatostatin, glucagon-like peptide 1, and other agonists and antagonists. The tight regulation of parietal cells ensures the proper secretion of HCl. The H+-K+-ATPase enzyme expressed in parietal cells regulates the exchange of cytoplasmic H+ for extracellular K+. The H+ secreted into the gastric lumen by the H+-K+-ATPase combines with luminal Cl- to form gastric acid, HCl. Inhibition of the H+-K+-ATPase is the most efficacious method of preventing harmful gastric acid secretion. Proton pump inhibitors and potassium competitive acid blockers are widely used therapeutically to inhibit acid secretion. Stimulated delivery of the H+-K+-ATPase to the parietal cell apical surface requires the fusion of intracellular tubulovesicles with the overlying secretory canaliculus, a process that represents the most prominent example of apical membrane recycling. In addition to their unique ability to secrete gastric acid, parietal cells also play an important role in gastric mucosal homeostasis through the secretion of multiple growth factor molecules. The gastric parietal cell therefore plays multiple roles in gastric secretion and protection as well as coordination of physiological repair.