The Effects of Switching to Vonoprazan, a Novel Potassium-Competitive Acid Blocker, on Gastric Acidity and Reflux Patterns in Patients with Erosive Esophagitis Refractory to Proton Pump Inhibitors

Treatment Response With Potassium-competitive Acid Blockers Based on Clinical Phenotypes of Gastroesophageal Reflux Disease: A Systematic Literature Review and Meta-analysis

Background/Aims

Gastroesophageal reflux disease (GERD) is typically managed based on the clinical phenotype. We evaluated the efficacy and safety of potassium-competitive acid blockers (PCABs) in patients with various clinical GERD phenotypes.

Methods

Core databases were searched for studies comparing PCABs and proton pump inhibitors (PPIs) in clinical GERD phenotypes of erosive reflux disease (ERD), non-erosive reflux disease (NERD), PPI-resistant GERD and night-time heartburn. Additional analysis was performed based on disease severity and drug dosage, and pooled efficacy was calculated.

Results

In 9 randomized controlled trials (RCTs) evaluating the initial treatment of ERD, the risk ratio for healing with PCABs versus PPIs was 1.09 (95% CI, 1.04-1.13) at 2 weeks and 1.03 (95% CI, 1.00-1.07) at 8 weeks, respectively. PCABs exhibited a significant increase in both initial and sustained healing of ERD compared to PPIs in RCTs, driven particularly in severe ERD (Los Angeles grade C/D). In 3 NERD RCTs, PCAB was superior to placebo in proportion of days without heartburn. Observational studies on PPI-resistant symptomatic GERD reported symptom frequency improvement in 86.3% of patients, while 90.7% showed improvement in PPIresistant ERD across 5 observational studies. Two RCTs for night-time heartburn had different endpoints, limiting meta-analysis. Pronounced hypergastrinemia was observed in patients treated with PCABs.

Conclusions

Compared to PPIs, PCABs have superior efficacy and faster therapeutic effect in the initial and maintenance therapy of ERD, particularly severe ERD. While PCABs may be an alternative treatment option in NERD and PPI-resistant GERD, findings were inconclusive in patients with night-time heartburn.

A systematic review and meta-analysis of the efficacy of vonoprazan for proton pump inhibitor-resistant gastroesophageal reflux disease

BACKGROUND AND AIM

Up to 40% of gastroesophageal reflux disease (GERD) patients experience inadequate symptom relief with a proton pump inhibitor (PPI), termed PPI-resistant or refractory GERD. Vonoprazan, a potassium-competitive acid blocker, has better efficacy than PPI in suppressing gastric acid secretion. This meta-analysis summarizes the efficacy and safety of vonoprazan for treating PPI-resistant GERD (both erosive esophagitis [EE] and non-erosive reflux disease [NERD]).

METHODS

Four electronic databases (Medline, Embase, SCOPUS, and CENTRAL) were searched for studies indexed until August 1, 2023. Both observational studies and clinical trials assessing the efficacy and safety of vonoprazan in PPI-resistant GERD were included. Efficacy outcomes included healing and maintenance rates of EE and improvement of the Frequency Scale for Symptoms of GERD (FSSG) scores. Serious adverse events (SAEs) were considered a safety outcome. The modified Newcastle-Ottawa Scale (NOS) was used to assess study quality.

RESULTS

Twelve studies were included in this meta-analysis. Healing rates of PPI-resistant EE with vonoprazan 20 mg were 91.7% (95% CI 86.8-94.8%) and 88.5% (95% CI 69.7-96.2%) at weeks 4 and 8, respectively. For healed PPI-resistant EE, the overall maintenance rates with vonoprazan 10 mg were 82.6% (95% 61.2-95.0%) at week 8, 86.0% (95% CI 72.1-94.7%) at week 24, and 93.8% (95% CI 69.8-99.8%) at week 48. FSSG scores were improved in 74.6% (95% CI 65.8-81.7%) and 51.9% (95% CI 37.8-65.7%) of patients at weeks 4 and 8. Overall, no SAE was reported.

CONCLUSION

Vonoprazan demonstrated high efficacy in the healing and maintenance of PPI-resistant EE and moderate efficacy for the improvement of FSSG score. Vonoprazan was well tolerated in PPI-resistant GERD patients.

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.

Potassium-competitive acid blockers and gastroesophageal reflux disease

Proton pump inhibitors (PPIs), the most commonly used antisecretory medi-cations in the management of reflux illness, virtually eliminate elective surgery for ulcer disease, and relegate anti-reflux surgery to patients with gastroesophageal reflux disease (GERD) who are inadequately managed by medical therapy. However, PPI medications still leave some therapeutic demands of GERD unmet. Furthermore, up to 40%-55% of daily PPI users have chronic symptoms, due to PPI refractoriness. Potassium-competitive acid blockers (P-CABs) transcend many of the problems and limits of PPIs, delivering quick, powerful, and extended acid suppression and allowing for treatment of numerous unmet needs. Recently, it has become clear that compromised mucosal integrity plays a role in the etiology of GERD. As a result, esophageal mucosal protection has emerged as a novel and potential treatment approach. An increasing body of research demonstrates that when P-CABs are used as primary drugs or add-on drugs (to regular treatment), they provide a considerable extra benefit, particularly in alleviating symptoms that do not respond to PPI therapy.

Use of vonoprazan, a novel potassium-competitive acid blocker, for the treatment of proton pump inhibitor-refractory reflux esophagitis in patients with systemic sclerosis

Objective

Proton pump inhibitor-refractory reflux esophagitis is one of the intractable conditions of systemic sclerosis for which new treatments are required. Vonoprazan is a novel potassium-competitive acid blocker and has been shown to have several advantages over conventional proton pump inhibitors, including a long duration of gastric acid suppression.

Methods

To investigate the efficacy of vonoprazan for treating proton pump inhibitor-refractory reflux esophagitis in patients with systemic sclerosis, 10 patients with proton pump inhibitor-refractory reflux esophagitis who were switched to vonoprazan were selected from our systemic sclerosis database. Reflux esophagitis was evaluated by endoscopy, and gastroesophageal reflux disease-related symptoms were assessed by the frequency scale for the symptoms of gastroesophageal reflux disease questionnaire before and after switching from proton pump inhibitor to vonoprazan at an average interval of 3.5 [2-5.5] months.

Results

After switching patients to vonoprazan, the endoscopic findings of reflux esophagitis were significantly improved (p = .033), and six patients (60%) achieved mucosal healing. The total frequency scale for the symptoms of gastroesophageal reflux disease score was also significantly decreased (p = .043), mainly by improving the acid reflux score. Vonoprazan was well tolerated and was continued for 15.5 [11.25-23.75] months in all patients.

Conclusion

Vonoprazan is a potential treatment option for treating proton pump inhibitor-refractory reflux esophagitis in systemic sclerosis patients.

Equine Squamous Gastric Disease: Prevalence, Impact and Management

This narrative review explores the etiopathogenesis, clinical signs, diagnosis and treatment of ESGD (equine squamous gastric disease) and discusses the impact of this commonly encountered condition on the equine industry. ESGD refers specifically to peptic injury of the squamous mucosa of the stomach. Prevalence is highest in performance horses, but the disease has been documented across many breeds and ages, including in feral horses and foals. The pathogenesis of ESGD is well understood. Intensive management and exercise are important factors that contribute to a disruption of the normal stratification of gastric pH. This results in exposure of the vulnerable squamous mucosa to acid, leading to ulceration. Clinical signs are variable and there is little evidence to support a direct association between reported signs and the presence or absence of lesions seen on gastroscopy. Management is aimed at acid suppression and mitigation of known risk factors.

Application of potassium competitive acid blockers in acid-related diseases

Acid-related diseases (ARDs) are common chronic diseases of the digestive system. Proton pump inhibitors (PPIs) have become the first-line drugs for the treatment of acid-related diseases. However, PPIs display some limitations in clinical application, such as short half-life, slow action, insufficient acid inhibition, pharmacological effects affected by CYP2C19 gene polymorphism, and nocturnal acid breakthrough, which lead to insufficient symptom remission of ARDs, as well as refractoriness, relapse, and even direct decline in health-related quality of life and increased economic burden. Potassium competitive acid blockers (P-CABs) are a class of novel anti-secretory drugs, which can overcome the limitations of traditional PPIs and show satisfactory acid inhibition effect and safety in clinical application. They may become a new strategy to solve the unsatisfied medical needs in the treatment of ARDs, but their potential adverse reactions remain to be monitored. In this article, we review the challenges in the treatment of acid-related diseases, and the advantages and prospects of P-CABs in the prevention and treatment of ARDs.

Long-term vonoprazan therapy is effective for controlling symptomatic proton pump inhibitor-resistant gastroesophageal reflux disease

Vonoprazan, a novel potassium-competitive acid blocker, results in greater inhibition of gastric acid secretion than proton pump inhibitors (PPI). The aim of this study was to assess the long-term outcomes of patients with PPI-resistant gastroesophageal reflux disease (GERD) treated with vonoprazan. The medical records of patients with symptomatic GERD treated with vonoprazan for 1 year were retrospectively reviewed. Changes in abdominal symptoms were assessed using the Izumo scale, a self-reported questionnaire which is useful in evaluating the symptoms of GERD, epigastric pain, postprandial distress, constipation and diarrhea, and is commonly used in routine clinical practice. A total of 30 patients were included and stratified into a non-erosive (n=22) and erosive group (n=8). At baseline, postprandial distress symptoms were significantly greater in the non-erosive group compared with the erosive group (P=0.013). Even with vonoprazan therapy, symptoms of GERD in the non-erosive group were refractory compared with the erosive group, and required additional treatment in a larger proportion of patients (45 vs. 13%). GERD symptoms in the non-erosive group significantly improved from baseline and remained better after 1 year of vonoprazan therapy, similar to the erosive group. In addition, vonoprazan improved epigastric pain and postprandial distress symptoms in the non-erosive group, and 1 year of vonoprazan therapy did not aggravate constipation or diarrhea. In conclusion, 1 year of vonoprazan therapy improves GERD symptoms in patients with PPI-resistant GERD.

The Gastroprotective Effect of Small Molecule Oligopeptides Isolated from Walnut (Juglans regia L.) against Ethanol-Induced Gastric Mucosal Injury in Rats

The study investigated the protective effect of walnut oligopeptides (WOPs) against ethanol-induced gastric injury using Sprague-Dawley (SD) rats. Rats were randomly divided into seven groups based on body weight (10/group), normal group, ethanol group, whey protein group (220 mg/kg body weight), omeprazole group (20 mg/kg body weight), and three WOPs groups (220, 440, 880 mg/kg body weight). After 30 days of treatment with WOPs, rats were given 5 mL/kg absolute ethanol by gavage to induce gastric mucosal injury. Gastric ulcer index (GUI) were determined and the following measured; gastric content pH, gastric mucin, endogenous pepsinogens (PG), prostaglandin E2 (PGE2), inflammatory cytokines, oxidative stress indicators, and the expression of apoptosis-related proteins were measured to evaluate the gastroprotective effect of WOPs. The results showed that the administration with WOPs markedly mitigated the hemorrhagic gastric lesions caused by ethanol in rats, and decreased the GUI, the gastric content pH, PG1, PG2, and NO levels, enhanced mucin and PGE2. Also, WOPs repressed gastric inflammation through the reduction of TNF-α, IL-6, IL-1β and increase IL-10 levels, and revealed antioxidant properties with the enhancement of superoxide dismutase, glutathione, and catalase activity, while reduction of malondialdehyde. Moreover, WOPs treatment significantly down-regulated Bax, caspase-3 and nuclear factor-κB p65 (NF-κB p65) expression, while up-regulating the expression of Bcl-2 and inhibitor kappa Bα (IκBα) protein. These results indicated that WOPs have protective effects against ethanol-induced gastric mucosal injury in rats through anti-inflammatory, anti-oxidation, and anti-apoptosis mechanisms.

Novel Therapies for Gastroesophageal Reflux Disease: Beyond Proton Pump Inhibitors

PURPOSE OF REVIEW

Despite the many areas of unmet needs in gastroesophageal reflux disease (GERD), proton pump inhibitors (PPIs) remain the cornerstone of medical therapy. However, since their introduction, the therapeutic limitations of PPIs in GERD management have been increasingly recognized.

RECENT FINDINGS

In this review we discuss the new medical, endoscopic, and surgical therapeutic modalities that have been developed over the last decade. They include the potassium-competitive acid blockers (P-CABs) which provide a rapid onset, prolonged, and profound acid suppression, mucosal protectants which promote the physiological protective barrier of the esophageal mucosa, new prokinetics and neuromodulators. There are growing numbers of novel therapeutic endoscopic techniques that are under investigation or were recently introduced into the market, further expanding our therapeutic armamentarium for GERD. The development of diverse therapeutic modalities for GERD, despite the availability of PPIs, suggests that there are many areas of unmet need in GERD that will continue and drive future exploration for novel therapies.

Cost-utility analysis of a 'vonoprazan-first' strategy versus 'esomeprazole- or rabeprazole-first' strategy in GERD

BACKGROUND

Gastroesophageal reflux disease (GERD) can be treated using a vonoprazan-first strategy (first-line treatment with vonoprazan), or esomeprazole-first/rabeprazole-first strategies (first-line treatment with proton-pump inhibitors [PPIs], esomeprazole/rabeprazole, followed by a switch to vonoprazan). This cost-utility analysis used long-term simulation modeling to evaluate the cost-effectiveness of a vonoprazan-first strategy compared with the esomeprazole-first and rabeprazole-first strategies.

METHODS

A Markov simulation model was developed to evaluate the cost-effectiveness of vonoprazan-first, esomeprazole-first, and rabeprazole-first strategies, comprising healing and maintenance therapies, over 5 years (4-week cycles). Healing therapy began with the administration of a normal dose of drug per real-world practice. If patients were not healed endoscopically, either a longer duration of healing therapy was provided (vonoprazan), the dose was increased (rabeprazole), or patients were switched to vonoprazan (immediately for esomeprazole, and after dose-escalation for rabeprazole, respectively). Healed patients received maintenance (lower/same dose as healing therapy). Recurrence resulted in re-challenge with healing therapy. Transition probabilities were derived from the results of indirect comparisons (network meta-analysis) and costs calculated from the Japanese payer perspective. Outcomes were defined as quality-adjusted life years (QALYs), with utilities based on published values.

RESULTS

Expected costs of the vonoprazan-, esomeprazole-, and rabeprazole-first strategies were ¥36,194, ¥76,719, and ¥41,105, respectively, over 5 years. QALY gains for vonoprazan-first strategy versus the esomeprazole- and rabeprazole-first strategies were 0.014 and 0.003, respectively. Both estimated incremental cost-effectiveness ratios were dominant and robust to two sensitivity analyses.

CONCLUSIONS

Vonoprazan-first strategy increased QALYs and appeared to be cost-effective for GERD patients compared with the esomeprazole- or rabeprazole-first strategies.

Intraluminal therapy for Helicobacter pylori infection

BACKGROUND AND AIM

Several strategies have been proposed to increase the eradication rate of Helicobacter pylori. However, the widespread increasing resistance rates to current multiple-dose oral antibiotic therapies call for alternative therapeutic approaches. We aim to develop a novel intraluminal therapy for H. pylori infection (ILTHPI).

METHODS

From April 2017 to December 2017, 100 H. pylori-infected treatment-naïve patients with upper abdominal pain or discomfort underwent endoscopic examinations and concomitant ILTHPI, which comprised the control of intragastric pH, the irrigation of gastric mucosal surface with a mucolytic agent, and the application of single-dose medicaments containing antibiotic powders. The safety profiles while conducting ILTHPI and adverse events after ILTHPI were evaluated. The success of eradication was assessed based on the result of the ¹³ C-urea breath test 6 weeks after ILTHPI. In addition, a patient with successful ILTHPI was reconfirmed by a negative H. pylori stool antigen test four to 6 months after ILTHPI to exclude short-term recurrence.

RESULTS

All the 100 enrolled patients completed the ILTHPI with good safety profiles and mild adverse events (6%). Five patients dropped out, and 51 of 95 patients (53.7%) achieved successful eradication immediately after endoscopic examinations. All 51 patients revealed negative stool H. pylori antigen tests four to 6 months after successful ILTHPI. No short-term recurrence was observed.

CONCLUSIONS

We have developed a novel therapeutic approach. With the ILTHPI, H. pylori can be eradicated immediately by administrating a single-dose regimen while conducting an endoscopic examination.

CLINICAL TRIALS NUMBER

NCT03124420.

Efficacy of on-demand therapy using 20-mg vonoprazan for non-erosive reflux disease

BACKGROUND

To evaluate the efficacy of on-demand therapy using 20-mg vonoprazan for non-erosive reflux disease.

METHODS

On-demand therapy by taking one 20-mg tablet of vonoprazan only when reflux symptoms occurred was performed for 8 weeks by 30 patients (11 men, mean age: 67.8) with non-erosive reflux disease who responded well to maintenance therapy using proton pump inhibitor and answered "very satisfied" or "satisfied" to an overall satisfaction survey (5-grade scale). The degree of overall satisfaction with the treatment, score of symptoms, and fasting gastrin levels before breakfast was examined before and after on-demand therapy. The number of vonoprazan tablets taken and the frequency (regular, temporary, rare) of its administration were also investigated.

RESULTS

All patients completed 8-week on-demand therapy with 20-mg vonoprazan. Comparisons of patient satisfaction levels before and after therapy revealed no significant differences in the number of patients who were very satisfied and satisfied with the therapy. Furthermore, there were no significant differences in score of symptoms or gastrin levels before and after therapy. During 8-week on-demand therapy, patients took 11 tablets (median) (7.0-18.0 tablets: 25-75 percentiles), and 30.0% of patients (n = 9) took vonoprazan on a regular basis (at least 2 tablets a week).

CONCLUSION

On-demand therapy with 20-mg vonoprazan exerted equivalent effects to continuous PPI maintenance therapy for patients with non-erosive reflux disease.

Proton Pump Inhibitor-Refractory Gastroesophageal Reflux Disease

Proton pump inhibitor (PPI)-refractory gastroesophageal reflux disease (GERD) is defined by the presence of troublesome GERD symptoms despite PPI optimization for at least 8 weeks in the setting of ongoing documented pathologic gastroesophageal reflux. It arises from a dysfunction in protective systems to prevent reflux and as propagation of physiologic reflux events. Treatment possibilities include pharmacologic options, invasive management strategies, and endoluminal therapies. Management strategy should be personalized to the patient's needs and mechanistic dysfunction. This article reviews the definition, mechanisms, and management options for PPI-refractory GERD.

Vonoprazan versus proton-pump inhibitors for gastric endoscopic submucosal dissection-induced ulcers: a systematic review and meta-analysis

Acid secretion inhibitors are usually prescribed to promote the healing of artificial ulcers caused by endoscopic submucosal dissection (ESD) to reduce the risk of gastric perforation and delayed bleeding. Vonoprazan is a newer agent that has been shown to be more potent than a proton-pump inhibitor (PPI). However, it remains unclear whether vonoprazan is more effective than PPI in promoting healing of ulcers caused by ESD. Medline and Embase databases were searched through January 2018 for studies that compared the rate of complete healing of ulcers caused by ESD and post-ESD delayed bleeding in patients who received vonoprazan versus those who received PPI after ESD. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using a random-effect model, generic inverse variance method. The between-study heterogeneity was quantified using the Q-statistic and I. A total of six studies consisting of 461 patients were identified. The likelihood that ulcers caused by ESD were completely healed at 4-8 weeks after the procedure was significantly higher among patients who received vonoprazan compared with those who received PPI, with a pooled OR of 2.27 (95% CI=1.38-3.73; I=0%). The risk of developing post-ESD delayed bleeding was also numerically lower among those who received vonoprazan, with a pooled OR of 0.79, although the result did not reach statistical significance (95% CI=0.18-3.49; I=29%). This study found that patients who received vonoprazan after ESD had a significantly higher rate of completely healed ulcers compared with those who received PPI.

Pathophysiology of Potassium-competitive Acid Blocker-refractory Gastroesophageal Reflux and the Potential of Potassium-competitive Acid Blocker Test

BACKGROUND/AIMS

Potassium-competitive acid blockers are expected to be the next generation of drugs for the treatment of diseases caused by gastric acid. In 2015, vonoprazan fumarate, a novel potassium-competitive acid blocker, was approved by the Japanese health insurance system. Since its approval, patients refractory to vonoprazan can be encountered in clinical settings. We designed this study to clarify the pathophysiology of gastroesophageal reflux disease refractory to vonoprazan.

METHODS

In this retrospective study, we involved patients who had refractory symptoms after administration of standard-dose proton pump inhibitors or vonoprazan and underwent diagnostic testing with esophageal high-resolution manometry and 24-hour multichannel intraluminal impedance and pH monitoring while using proton pump inhibitors or vonoprazan. Patients were diagnosed based on the Rome IV criteria for functional gastrointestinal disorders and diagnostic test results.

RESULTS

Twenty-seven patients were analyzed during this study. Gastric pH ≥ 4 was sustained for a longer period of time, and the esophageal acid exposure time and number of acid reflux events were shorter in the vonoprazan group than in the proton pump inhibitor group. The percentage of patients diagnosed with acidic gastroesophageal reflux disease in the vonoprazan group was lower than that in the proton pump inhibitor group.

CONCLUSIONS

Intra-gastric pH and acid reflux were strongly suppressed by 20-mg vonoprazan. When patients with gastroesophageal reflux disease present symptoms after administration of 20-mg vonoprazan, the possibility of pathophysiologies other than acid reflux should be considered.

Efficacy of On-Demand Therapy Using 20-mg Vonoprazan for Mild Reflux Esophagitis

BACKGROUND

The study aimed to evaluate the efficacy of on-demand therapy using 20-mg vonoprazan for mild reflux esophagitis (RE).

METHODS

On-demand therapy by taking one 20-mg tablet of vonoprazan only when reflux symptoms occurred was performed for 24 weeks using 30 patients with mild RE who were receiving maintenance therapy with proton pomp inhibitors (PPIs). The presence or absence of RE, degree of overall satisfaction with the treatment, score of symptoms, and fasting gastrin level before breakfast were examined before and after on-demand therapy. The number of tablets taken during the 24-week period was also noted.

RESULTS

One of the 30 patients dropped out of on-demand therapy 1 week after its initiation. Remission was maintained in 25 (86.2%) of the 29 patients (all 10 [100%] Los Angeles classification grade A patients and 15 (78.9%) of the 19 grade B patients). However, 4 grade B patients exhibited grade B relapse. There were no differences in the degree of overall satisfaction, score of symptoms or the gastrin level between PPI and on-demand therapies. The number of vonoprazan tablets taken during the observation period was 33 tablets (median)/24 weeks.

CONCLUSION

On-demand therapy using 20-mg vonoprazan tablets is an effective alternative maintenance therapy for mild RE.

Does the Novel Potassium-Competitive Acid Blocker Vonoprazan Cause More Hypergastrinemia than Conventional Proton Pump Inhibitors? A Multicenter Prospective Cross-Sectional Study

BACKGROUND/AIM

The long-term administration of proton pump inhibitors (PPIs) is useful for preventing recurrent reflux esophagitis. On the other hand, several adverse reactions, such as an increase in the blood gastrin level, have been reported. The aim of the present study was to examine the increase in the blood gastrin level due to the long-term administration of conventional PPIs compared with vonoprazan.

METHODS

A prospective cross-sectional study was conducted. We examined the blood gastrin levels of patients taking vonoprazan or conventional PPIs in whom the grade of atrophic gastritis had been endoscopically evaluated in the last year.

RESULTS

The blood gastrin level was significantly higher in the vonoprazan group than that in the PPI group in patients with milder or no atrophic gastritis, irrespective of the administration periods. However, no significant difference was observed between the groups in patients with severe atrophic gastritis.

CONCLUSION

Vonoprazan more markedly increased the blood gastrin level compared with conventional PPIs in patients with milder or no atrophic gastritis. This indicates that vonoprazan may have stronger acid-suppressing effects in such patients than conventional PPIs. Key Message: We should be aware of the potential development of hypergastrinemia during the long-term administration of vonoprazan, especially in patients with mild or no atrophic gastritis.

Evaluation of Esophageal Mucosal Integrity in Patients with Gastroesophageal Reflux Disease

BACKGROUND

Impaired esophageal mucosal integrity plays a role in causing symptoms of gastroesophageal reflux disease (GERD). Recently, the assessment of esophageal baseline impedance (BI) using the multichannel intraluminal impedance-pH (MII-pH) test was suggested as a surrogate technique for the study of esophageal mucosal integrity and was reported to be useful in distinguishing GERD from non-GERD. However, measuring BI requires a 24-h testing period, is complicated, and causes considerable patient discomfort.

SUMMARY

Recently, endoscopy-guided catheters that can measure mucosal impedance (MI) and mucosal admittance (MA), which is the inverse of impedance, were developed, and their usefulness in measuring MI and MA for the diagnosis of GERD has been reported. In these studies, esophageal MI values were significantly lower in patients with GERD than in those without GERD. In contrast, esophageal MA was significantly higher in patients with GERD than in those without. Furthermore, we reported that MA is inversely correlated with BI and correlated with acid exposure time. Key Messages: Endoscopy-guided real-time measurement of MI and MA may allow the estimation of mucosal integrity and may be a useful diagnostic tool for patients with GERD in a manner similar to 24-h MII-pH monitoring.

New Medical Approach to Functional Dyspepsia, from Core Symposium 3, Japan Gastroenterological Association 2015-2017

In the annual meeting of the Japan Gastroenterological Association (JGA), the scientific organizing committee selected the serial topics for the core symposium. One of the core symposia held during 2015-2017 was entitled "New medical approach to functional dyspepsia (FD)." In 2015, the subtitle of this symposium was "Helicobacter pylori gastritis and FD." In 2016, the subtitle of this symposium was "overlap with other functional GI disorders." In 2017, the subtitle was "therapeutic approach to FD." During these 3 years, a total of 24 presentations were included in Core Symposium 3 and deep and intensive discussions were carried out.

Hypergastrinemia in Long-Term Use of Proton Pump Inhibitors

BACKGROUND/AIM

The use of proton pump inhibitors (PPIs) is known to lead to hypergastrinemia; however, the data in patients with atrophic gastritis is still lacking. The aim of this study was to investigate the effects of long-term PPIs use on the gastrin levels in patients with atrophic gastritis and to determine factors affecting hypergastrinemia in long-term users of PPIs.

METHODS

Serum Helicobacter pylori IgG, gastrin and pepsinogen levels were measured. Atrophic gastritis was assessed by upper gastrointestinal endoscopies based on the Kimura-Takemoto classification and pepsinogen levels. CYP2C19 polymorphisms were assessed using DNA extracted from peripheral blood.

RESULTS

A total number of 382 patients (275 men and 107 women) were enrolled. Median serum gastrin levels were higher in PPI users than in non- users (234 vs. 113 pg/mL, p < 0.001) and in women than in men (252 vs. 155 pg/mL, p = 0.006). Gastrin levels were significantly associated with corpus atrophy only in the subgroup of non-users of PPIs. Multivariate analysis revealed that hypergastrinemia (over 150 pg/mL) was significantly associated with PPI use (OR 5.30; 95% CI 3.32-8.47), women (OR 2.22; 95% CI 1.33-3.72) and corpus atrophy (OR 1.82; 95% CI 1.14-2.90).

CONCLUSION

PPI use, women and corpus atrophy were risk factors for hypergastrinemia. Gender, but not corpus atrophy, affected the gastrin levels in long-term users of PPIs.

Intestinal Dysbiosis Secondary to Proton-Pump Inhibitor Use

BACKGROUND

Gut dysbiosis associated with the use of proton-pump inhibitors (PPIs) has been found to lead to the occurrence of infectious and inflammatory adverse events. A longitudinal observational cohort study has demonstrated the heightened risk of death associated with PPI use.

SUMMARY

We evaluated meta-analyses to determine the association between PPI use and infectious and inflammatory diseases. Meta-analyses showed that PPI use is a potential risk for the development of enteric infections caused by Clostridium difficile, as well as small intestinal bacterial overgrowth, spontaneous bacterial peritonitis, community-acquired pneumonia, hepatic encephalopathy, and adverse outcomes in inflammatory bowel disease. We also examined changes in the composition and function of the gut microbiota with the use of PPIs. PPI use significantly increased the presence of Streptococcaceae and Enterococcaceae, which are risk factors for C. difficile infection, and decreased that of Faecalibacterium, a commensal anti-inflammatory microorganism. Key Message: High-throughput, microbial 16S rRNA gene sequencing has allowed us to investigate the association between the gut microbiome and PPI use. Future prospective comparison studies are necessary to confirm this association, and to develop new strategies to prevent complications of PPI use.

Comparison of the Effects of Vonoprazan and Lansoprazole for Treating Endoscopic Submucosal Dissection-Induced Artificial Ulcers

BACKGROUND

Vonoprazan exhibits a more potent, rapid, and longer-lasting inhibitory effect on gastric acid secretion than proton pump inhibitors; however, whether it is more effective than PPI for treating endoscopic submucosal dissection (ESD)-induced artificial ulcers remains controversial.

AIM

This study aimed to assess and compare the effects of vonoprazan and lansoprazole for treating ESD-induced artificial ulcers.

METHODS

This prospective, randomized controlled trial enrolled 149 patients who underwent ESD for the treatment of early gastric neoplasms from April 2015 to May 2017. They were randomly treated with either 20 mg/day vonoprazan (V group) or 30 mg/day lansoprazole (L group) orally. The primary end points were the area and shrinkage ratio of the ulcers at 4 and 8 weeks post-ESD.

RESULTS

Data from 127 patients were analyzed, which showed that the 4- and 8-week healing ratios were not significantly different between the V and L groups (4 weeks, 16.3 vs. 25.8%; 8 weeks, 86.9 vs. 90.9%, respectively). Similarly, the shrinkage ratio, categorized as less than 90%, 90% or more but less than 100%, or 100% at 4 weeks and as less than 100% or 100% at 8 weeks were not statistically different between the V and L groups (4 weeks: 12, 41, 8 vs. 13, 41, 12, p = 0.7246; 8 weeks: 9, 52 vs. 9, 57, p = 0.8568). Delayed bleeding was also not significantly different between both the groups (5.4 vs. 5.3%; p = 0.9844).

CONCLUSIONS

Vonoprazan is as effective as lansoprazole in treating ESD-induced ulcers.

Vonoprazan fumarate, a novel potassium-competitive acid blocker, in the management of gastroesophageal reflux disease: safety and clinical evidence to date

Potassium-competitive acid blocker (P-CAB) is a class of drug that competitively blocks the potassium-binding site of H⁺, K⁺-adenosine triphosphate (ATP)ase. Although the history of this class of drugs started over 30 years ago, clinical use of two P-CABs, revaprazan and vonoprazan, were only recently approved in Korea and Japan, respectively. Among them, vonoprazan has several advantages over conventional proton-pump inhibitors (PPIs), including rapid onset of action, long duration of acid suppression, fewer interindividual variations in terms of acid suppression, and minimum dietary influence on its action. These advantages of vonoprazan have been proved in clinical trials conducted for license approvals for several acid-related diseases. In this review article, current evidence of vonoprazan in the management of gastroesophageal reflux disease (GERD) will be summarized. Since the clinical trial data, as well as postmarketed clinical data, have consistently demonstrated superiority of vonoprazan over conventional PPIs in terms of achieving healing of mucosal breaks and maintaining the healing, it may provide an excellent, if not complete, option for fulfilling some of the unmet needs for current GERD therapy. The safety problem of vonoprazan is also discussed, as more pronounced hypergastrinemia inevitably ensues with its use.