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

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).

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.

Severe Hypomagnesemia Associated with the Long-term Use of the Potassium-competitive Acid Blocker Vonoprazan

Hypomagnesemia caused by a proton pump inhibitor (PPI) was first reported in 2006. We herein report a case of hypomagnesemia due to the long-term use of vonoprazan, a potassium-competitive acid blocker (P-CAB). A 66-year-old man was admitted to our hospital complaining of disturbance of consciousness with evidence of hypomagnesemia noted on blood testing. The long-term use of vonoprazan was considered the cause of his hypomagnesemia, so it was discontinued, after which the hypomagnesemia improved. Hypomagnesemia can be induced not only by PPI treatment but also following the long-term use of P-CAB.

GASTROESOPHAGEAL REFLUX DISEASE: A PRACTICAL APPROACH

Gastroesophageal reflux disease (GERD) presents typical manifestations such as heartburn and/or regurgitation as well as atypical manifestations such as throat symptoms, laryngitis, hoarseness, chronic cough, asthma, and sleep alterations. There are two phenotypes of the disease: erosive GERD, when erosions are identified by upper digestive endoscopy, and non-erosive GERD, when the esophageal mucosa presents a normal endoscopic aspect. Relevant clinical findings are usually absent in the physical examination, but it should be highlighted that obesity is an important aggravating factor of reflux. The treatment is established based on clinical findings and, according to the clinical situation, on complementary exams such as upper digestive endoscopy. In dubious cases where a precise diagnosis is required, the indicated test is esophageal pHmetry or impedance-pHmetry. Clinical treatment is divided into behavioral/dietary measures and pharmacological measures. Most patients benefit from clinical treatment, but surgical treatment may be indicated in the presence of a larger hiatal hernia and complications of the disease.

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.

Antimicrobial resistance and virulence in Helicobacter pylori: Genomic insights

Microbes evolve rapidly by modifying their genome through mutations or acquisition of genetic elements. Antimicrobial resistance in Helicobacter pylori is increasingly prevalent in India. However, limited information is available about the genome of resistant H. pylori isolated from India. Our pan- and core-genome based analyses of 54 Indian H. pylori strains revealed plasticity of its genome. H. pylori is highly heterogenous both in terms of the genomic content and DNA sequence homology of ARGs and virulence factors. We observed that the H. pylori strains are clustered according to their geographical locations. The presence of point mutations in the ARGs and absence of acquired genetic elements linked with ARGs suggest target modifications are the primary mechanism of its antibiotic resistance. The findings of the present study would help in better understanding the emergence of drug-resistant H. pylori and controlling gastric disorders by advancing clinical guidance on selected treatment regimens.

Combinations of antibiotics and vonoprazan for the treatment of Helicobacter pylori infections-Exploratory study

BACKGROUND

Vonoprazan fumarate is a novel potassium-competitive acid blocker more effective in suppressing acid production than proton pump inhibitors (PPIs) and when combined with antibiotics has been used to eradicate Helicobacter pylori (H. pylori) infection. However, it has not yet been examined in an Australian setting. This study aimed to report on the efficacy and safety of vonoprazan-containing antibiotic combination therapies in the eradication of H. pylori.

METHODS

A single-center, exploratory, clinical review of patients 18 years or over, positive for H. pylori on Urea Breath Test (UBT), and/or histopathology who underwent a 10-day treatment of combination antibiotics plus vonoprazan between January 2017 and September 2019 was conducted. Eleven different combinations of antibiotics that included 2-5 different antibiotics predominantly amoxicillin, rifabutin, levofloxacin, furazolidone, nitazoxanide, and tetracycline were included. The eradication success was based on negative UBT results and/or histopathology results after the treatment. Descriptive statistics were summarized.

RESULTS

One hundred and fifty-three patients (Female n = 74, 48%) with a positive for H. pylori were treated with vonoprazan-containing antibiotic combination therapy during the study period. Of the 153 patients, 48 (31%) had previously failed a PPI-based H. pylori treatment. Follow-up was available for 66/153 (43%) patients. In those who completed follow-up, overall eradication was achieved in 97% (64/66) of patients. In the subgroup of patients treated for the first time, eradication was achieved in 100% (44/44). In those who had failed prior, non-vonoprazan-containing treatment, eradication was achieved in 91% (20/22) of patients.

CONCLUSIONS

Vonoprazan-containing antibiotic therapy is an effective H. pylori eradication treatment. It is capable of achieving 100% efficacy in patients treated for the first time and even 91% efficacy in patients with previous eradication failure. Subsequent studies utilizing a factorial design will be needed to optimize each regimen as most regimens contained more than two antibiotics.

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.

Effect of Food on the Pharmacokinetics and Pharmacodynamics of a Single Oral Dose of Tegoprazan

PURPOSE

Tegoprazan is a potassium-competitive acid blocker (P-CAB) that is designed to treat acid-related diseases through a fundamentally different mechanism than that of proton pump inhibitors (PPIs). Because PPIs inhibit only activated parietal cell H⁺/K⁺ adenosine triphosphatase, stimulation of parietal cells by a meal is necessary for optimal results. In contrast, P-CABs can inactivate proton pumps without acid activation and bind to both activated and inactivated adenosine triphosphatase. This study evaluates the effect of food consumption on the pharmacokinetic and pharmacodynamic properties of tegoprazan after a single oral dose in healthy men.

METHODS

In this open-label, 2-period crossover study, 24 healthy men were randomized to 1 of 2 treatment sequence groups: administration of tegoprazan under the fasting condition and administration of tegoprazan under the fed condition. The dosing periods of both sequence groups were separated by a washout period of 7 days. At each dosing period, the participants received a single dose of 200 mg of tegoprazan followed by pharmacokinetic and pharmacodynamic analysis.

FINDINGS

After the oral administration of 200 mg tegoprazan, the C_max was decreased and delayed under the fed condition compared with that of the fasting condition. However, no significant differences were observed in the AUC and the time of gastric acid suppression (inhibition of integrated acidity) during 24 hours.

IMPLICATIONS

The pharmacokinetic and pharmacodynamic properties of tegoprazan are independent of food effect; thus, tegoprazan could be administered regardless of the timing of food consumption in patients. ClinicalTrials.gov identifier: NCT01830309.

Development of Physiologically Based Pharmacokinetic Model for Orally Administered Fexuprazan in Humans

Fexuprazan is a new drug candidate in the potassium-competitive acid blocker (P-CAB) family. As proton pump inhibitors (PPIs), P-CABs inhibit gastric acid secretion and can be used to treat gastric acid-related disorders such as gastroesophageal reflux disease (GERD). Physiologically based pharmacokinetic (PBPK) models predict drug interactions as pharmacokinetic profiles in biological matrices can be mechanistically simulated. Here, we propose an optimized and validated PBPK model for fexuprazan by integrating in vitro, in vivo, and in silico data. The extent of fexuprazan tissue distribution in humans was predicted using tissue-to-plasma partition coefficients in rats and the allometric relationships of fexuprazan distribution volumes (V_SS) among preclinical species. Urinary fexuprazan excretion was minimal (0.29-2.02%), and this drug was eliminated primarily by the liver and metabolite formation. The fraction absorbed (Fa) of 0.761, estimated from the PBPK modeling, was consistent with the physicochemical properties of fexuprazan, including its in vitro solubility and permeability. The predicted oral bioavailability of fexuprazan (38.4-38.6%) was within the range of the preclinical datasets. The C_max, AUC_last, and time-concentration profiles predicted by the PBPK model established by the learning set were accurately predicted for the validation sets.

The crystal structure of 1-[5-(2-fluorophenyl)-1-(pyridine-3-sulfonyl)-1H-pyrrol-3-yl]-N-methylmethanaminium 3-carboxyprop-2-enoate, C21H20FN3O6S

C21H20FN3O6S, monoclinic, P21/n (no. 14), a = 7.8502(4) Å, b = 7.9892(4) Å, c = 34.9707(19) Å, β = 92.500(1)°, V = 2191.2(2) Å3, Z = 4, R gt (F) = 0.0502, wR ref(F 2) = 0.1361, T = 296(2) K.

Pharmacological Management of Gastro-Esophageal Reflux Disease: An Update of the State-of-the-Art

Gastro-esophageal reflux disease (GERD) is a highly prevalent, chronic disorder, whose knowledge remains limited and the management of these patients changes continuously. This review provides a summary of the most recent advancements in the pathogenesis of this disease and the new drugs introduced into the market to overcome some of the unmet needs of traditional therapies. Nowadays, the most fruitful diagnostic examinations are 24-hour impedance-pH monitoring, which allows us to separate true NERD from esophageal functional disorders and high-resolution manometry, which helps to exclude the existence of motility disorders sharing the same symptoms of GERD. Proton pump inhibitors (PPIs) remain the first-choice therapy in the treatment of GERD, but a consistent proportion of these patients continue to experience symptoms despite their intake. These cases pertain mainly to the subpopulation with non-erosive reflux disease (NERD) and represent very challenging clinical situations, because it is mandatory to understand the reasons for PPI failure. The management of these difficult patients requires necessarily to test them and avoid the use of empiric treatments that are often unsuccessful, costly and potentially dangerous. Recently, several new drugs have been used to increase the defensive properties of this mucosa with promising results in randomized clinical trials.

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.

Efficacy of Tegoprazan for Improving the Susceptibility of Antimicrobial Agents against Antibiotic-Resistant Helicobacter pylori

Background/Aims

Favorable outcomes of potassium-competitive acid blocker (PCAB)-containing eradication therapy have been reported. In fact, tegoprazan, a recently developed PCAB, was presumed to show good eradication efficacy even for resistant Helicobacter pylori. We aimed to investigate the anti-H. pylori efficacy of tegoprazan compared with that of vonoprazan.

Methods

A total of 220 resistant clinical H. pylori isolates were utilized. The anti-H. pylori efficacy of PCABs was determined by evaluating the minimum inhibitory concentrations (MICs) of clarithromycin, fluoroquinolone, metronidazole, and amoxicillin in combination with vonoprazan or tegoprazan by the agar dilution method. The impact of the mutations responsible for resistance development, such as 23S rRNA, gyrA, rdxA, frxA, and pbp1 mutations, was also analyzed.

Results

H. pylori growth was significantly inhibited in a medium containing 1 μg/mL clarithromycin with tegoprazan (128 μg/mL). The MICs of clarithromycin (46.3%), fluoroquinolone (46.7%), metronidazole (55.6%), and amoxicillin (34.5%) against resistant H. pylori isolates improved after tegoprazan administration. Tegoprazan demonstrated more frequent susceptibility acquisition with metronidazole than with vonoprazan (20.6% vs 4.7%, p=0.014). However, there were no significant differences depending on the mutational status of each antimicrobial agent.

Conclusions

Tegoprazan administration may improve the susceptibility of antimicrobial-resistant H. pylori, independent of acid suppression.

Direct Comparison of the Efficacy and Safety of Vonoprazan Versus Proton-Pump Inhibitors for Gastroesophageal Reflux Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Gastroesophageal reflux disease (GERD) is a common disorder, and is typically treated with proton-pump inhibitors (PPIs) as the recommended first-line therapy. Recently, a new potassium-competitive acid blocker, vonoprazan, was launched in Japan. It is uncertain whether the standard dose of vonoprazan 20 mg is superior to that of PPIs for GERD, so a direct comparison of the therapeutic effects and adverse events between vonoprazan 20 mg and PPIs is needed.

METHODS

MEDLINE, the Cochrane Central Register of Controlled Trials, and Embase were chosen as the literature sources. Randomized controlled trials for vonoprazan 20 mg and PPIs published in English were searched. Data from studies meeting the eligibility criteria were extracted individually by two researchers and compared to maintain consistency.

RESULTS

Fifty-six articles were identified in the databases, and one study was manually searched and added to the analysis, ultimately yielding six eligible studies. For the main analysis, the risk ratios (RR) of efficacy and adverse events between vonoprazan and PPIs were 1.06 (0.99-1.13) and 1.08 (0.96-1.22), respectively. Subgroup analysis for patients with severe esophagitis at baseline showed significantly higher results for vonoprazan than lansoprazole, with an RR of 1.14 (1.06-1.22).

CONCLUSIONS

Our findings suggest that vonoprazan is non-inferior to PPIs as therapy for patients with GERD. Subgroup analysis indicates that vonoprazan is more effective than PPIs for patients with severe erosive esophagitis. The safety outcomes for vonoprazan are similar to those for PPIs.

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.

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.

Proton pump inhibitors for chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a common and progressive disease characterised by chronic cough, airflow limitation and recurrent exacerbations. Since COPD exacerbations are linked to rising mortality and reduced quality of life, the condition poses a substantial burden on individuals, society and the healthcare system. Effective management of COPD exacerbations that includes treatment of related conditions in people with COPD is thus recognised as a relevant clinical question and an important research topic. Gastroesophageal reflux disease (GERD) is a known comorbidity of COPD, and pulmonary microaspiration of gastric acid is thought to be a possible cause of COPD exacerbations. Therefore, reducing gastric acid secretion may lead to a reduction in COPD exacerbations. Proton pump inhibitors (PPIs) are one of the most commonly prescribed medications and are recommended as first-line therapy for people with GERD because of their inhibitory effects on gastric acid secretion. Treatment with PPIs may present a viable treatment option for people with COPD.

OBJECTIVES

To evaluate the efficacy and safety of PPI administration for people with COPD, focusing on COPD-specific outcomes.

SEARCH METHODS

We searched the Cochrane Airways Register of Trials and conventional clinical trial registers from inception to 22 May 2020. We also screened bibliographies of relevant studies.

SELECTION CRITERIA

Parallel-group and cluster-randomised controlled trials (RCTs) that compared oral PPIs versus placebo, usual care or low-dose PPIs in adults with COPD were eligible for inclusion. We excluded cross-over RCTs, as well as studies with a duration of less than two months.

DATA COLLECTION AND ANALYSIS

Two independent review authors screened search results, selected studies for inclusion, extracted study characteristics and outcome data, and assessed risk of bias according to standard Cochrane methodology. We resolved discrepancies by involving a third review author. Primary outcomes of interest were COPD exacerbations, pneumonia and other serious adverse events. Secondary outcomes were quality of life, lung function test indices, acute respiratory infections and disease-specific adverse events. We extracted data on these outcome measures and entered into them into Review Manager software for analysis.

MAIN RESULTS

The search identified 99 records, and we included one multicentre RCT that randomised 103 adults with COPD. The 12-month RCT compared an oral PPI (lansoprazole) and usual care versus usual care alone. It was conducted at one tertiary care hospital and three secondary care hospitals in Japan. This study recruited participants with a mean age of 75 years, and excluded people with symptoms or history of GERD. No placebo was used in the usual care arm. Among the primary and secondary outcomes of this review, the study only reported data on COPD exacerbations and acute respiratory infections (the common cold). As we only included one study, we could not conduct a meta-analysis. The included study reported that 12 of the 50 people on lansoprazole had at least one exacerbation over a year, compared to 26 out of 50 on usual care (risk ratio 0.46, 95% CI 0.26 to 0.81). The frequency of COPD exacerbations per person in a year was also lower in the PPI plus usual care group than in the usual care alone group（0.34 ± 0.72 vs 1.18 ± 1.40; P < 0.001). The number of people with at least one cold over the year was similar in both groups: 26 people on lansoprazole and 27 people in the usual care group. We judged the evidence to be of low to very low certainty, according to GRADE criteria. The study reported no data on pneumonia and other serious adverse events, quality of life, lung function test indices or disease-specific adverse events. The risk of bias was largely low or unclear for the majority of domains, though the performance bias was a high risk, as the study was not blinded.

AUTHORS' CONCLUSIONS

Evidence identified by this review is insufficient to determine whether treatment with PPIs is a potential option for COPD. The sample size of the included trial is small, and the evidence is low to very low-certainty. The efficacy and safety profile of PPIs for people with COPD remains uncertain. Future large-scale, high-quality studies are warranted, which investigate major clinical outcomes such as COPD exacerbation rate, serious adverse events and quality of life.

Pathophysiology, diagnosis, and pharmacological treatment of gastro-esophageal reflux disease

INTRODUCTION

Gastro-esophageal reflux disease (GERD) is a highly prevalent, chronic, relapsing disorder, whose knowledge has increased in last years thanks to the advent of new sophisticated techniques, such as 24-h impedance-pH monitoring and high-resolution manometry, for the study of esophageal functions.

AREAS COVERED

This review provides an overview of our advancements in understanding the complex pathophysiology, improving the diagnosis and defining the modern pharmacological therapeutic approach to GERD.

EXPERT OPINION

The growing clinical application of impedance-pH testing has allowed us to know the diversity of patients with non-erosive reflux disease (NERD), who nowadays represent about 70% of the whole population with reflux symptoms. We have realized that NERD has to be considered as an umbrella term covering various subgroups with different pathophysiologies. The development of new impedance metrics, in particular mean nocturnal baseline impedance, seems to be promising in the improvement of the diagnostic process of this disease. There are no particularly innovative features in the pharmacological therapy of GERD, unless the interest toward drugs is able to increase the defense properties of esophageal mucosa and/or its protection. These compounds can be of help in combination with proton pump inhibitors in NERD patients with partial response to antisecretory drugs alone.

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.

Gastric acid inhibitor aggravates indomethacin-induced small intestinal injury via reducing Lactobacillus johnsonii

Proton pump inhibitors (PPIs) alter the composition of the intestinal microbiome, exacerbating indomethacin (IND)-induced small intestinal damage. Vonoprazan fumarate inhibits gastric acid secretion using a different mechanism from PPIs. We investigated the effects of both drugs on the intestinal microbiome and IND-induced small intestinal damage. We sought to clarify whether PPI-induced dysbiosis and worsening of the damage were due to a specific drug class effect of PPIs. Rabeprazole administration increased operational taxonomic unit numbers in the small intestines of C57BL/6 J mice, whereas the difference was not significant in the vonoprazan-treated group but exhibited a trend. Permutational multivariate analysis of variance of the unweighted UniFrac distances showed significant differences between vehicle- and vonoprazan- or rabeprazole-treated groups. L. johnsonii was the predominant microbial species, and the population ratio decreased after vonoprazan and rabeprazole administration. The vonoprazan- and rabeprazole-treated groups showed increased IND-induced damage. This high sensitivity to IND-induced damage was evaluated by transplantation with contents from the small intestine of mice treated with either vonoprazan or rabeprazole. Supplementation of L. johnsonii orally in mice treated with rabeprazole and vonoprazan prevented the increase in IND-induced small intestinal damage. In conclusion, both rabeprazole and vonoprazan aggravated NSAID-induced small intestinal injury by reducing the population of L. johnsonii in the small intestine via suppressing gastric acid secretion.

The potential role of potassium-competitive acid blockers in the treatment of gastroesophageal reflux disease

PURPOSE OF REVIEW

Gastroesophageal reflux disease (GERD) is primarily a motor disorder, but its pathogenesis is multifactorial. Although gastric acid secretion is usually normal in GERD patients, treatment with proton pump inhibitors (PPIs) has become the standard of care, despite increasing awareness of their shortcomings. In this article, a new class of antisecretory drugs (namely potassium-competitive acid blockers, P-CABs), developed to overcome these limitations, is discussed.

RECENT FINDINGS

P-CABs block the K exchange channel of the proton pump, resulting in rapid, competitive, reversible inhibition of acid secretion. These drugs offer a more rapid elevation of intragastric pH than PPIs, while maintaining similar antisecretory effect, the duration of which is dependent on half-life and can be prolonged with extended release formulations. Thus, P-CABs offer advances in the treatment of GERD including rapid heartburn relief, faster and more reliable healing of severe grades of erosive esophagitis, as a consequence of better control of nighttime acid secretion than PPIs.

SUMMARY

P-CABs overcome many of the drawbacks of PPIs. The unique antisecretory effects of vonoprazan might be especially useful in the long-term treatment of patients with Barrett's esophagus.

Gastric Parietal Cell Physiology and Helicobacter pylori-Induced Disease

Acidification of the gastric lumen poses a barrier to transit of potentially pathogenic bacteria and enables activation of pepsin to complement nutrient proteolysis initiated by salivary proteases. Histamine-induced activation of the PKA signaling pathway in gastric corpus parietal cells causes insertion of proton pumps into their apical plasma membranes. Parietal cell secretion and homeostasis are regulated by signaling pathways that control cytoskeletal changes required for apical membrane remodeling and organelle and proton pump activities. Helicobacter pylori colonization of human gastric mucosa affects gastric epithelial cell plasticity and homeostasis, promoting epithelial progression to neoplasia. By intervening in proton pump expression, H pylori regulates the abundance and diversity of microbiota that populate the intestinal lumen. We review stimulation-secretion coupling and renewal mechanisms in parietal cells and the mechanisms by which H pylori toxins and effectors alter cell secretory pathways (constitutive and regulated) and organelles to establish and maintain their inter- and intracellular niches. Studies of bacterial toxins and their effector proteins have provided insights into parietal cell physiology and the mechanisms by which pathogens gain control of cell activities, increasing our understanding of gastrointestinal physiology, microbial infectious disease, and immunology.

Vonoprazan versus proton pump inhibitors for the management of gastric endoscopic submucosal dissection-induced artificial ulcer: A systematic review with meta-analysis

BACKGROUND

Vonoprazan, a novel potassium-competitive acid blocking agent, has been used in the management of endoscopic submucosal dissection (ESD)-induced artificial ulcers. This study aimed to perform a systematic review and meta-analysis for the comparison of the effects of vonoprazan and proton pump inhibitors (PPIs) in treating ESD-induced artificial ulcers and preventing delayed bleeding in randomized controlled trial and cohort studies.

METHODS

We searched OVID-MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), Google Scholar, and clinical trial registries in April 2018 to identify all studies that assess and compare the effects of vonoprazan and PPI in treating ESD-induced artificial ulcers and preventing delayed bleeding. Primary outcome of ulcer healing rate and secondary outcomes of shrinkage rate, ulcer size, and delayed bleeding were studied.

RESULTS

A total of 1265 patients from 12 studies were included in the final analysis. Healing rate at 4 weeks post-ESD was significantly higher in the vonoprazan group than in the PPI group (relative ratio [RR] 1.20 [1.03-1.40]). However, healing rate at 8 weeks post-ESD was significantly higher in the PPI group than in the vonoprazan group (RR 0.68 [0.48-0.97]).There was no evidence of significant difference between groups in shrinkage rate at 4 weeks post-ESD, shrinkage rate at 8 weeks post-ESD, delayed bleeding, ulcer size at 0 weeks post-ESD, and ulcer size at 8 weeks post-ESD.

CONCLUSIONS

There was no substantial difference in ulcer healing and post-ESD bleeding between vonoprazan and PPIs. However, vonoprazan more rapidly and effectively treated artificial ulcers after ESD than did PPIs.

Management of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) continues to be one of the most prevalent gastrointestinal tract disorders. Management of GERD is individualized for each patient depending on severity of symptoms, complications of GERD and patient/physician preference. The different management options include life style modification, pharmacological therapy, minimally invasive procedures and surgery. The final decision regarding management should be made based on an individualized patient centered approach on a case-by-case basis in consultation with a multidisciplinary team including primary care physician, gastroenterologist and surgeon. We provide a comprehensive review for the management of GERD.

Role of Acid Suppression in Acid-related Diseases: Proton Pump Inhibitor and Potassium-competitive Acid Blocker

Proton pump inhibitors are commonly utilized for the treatment of gastric acid-related diseases, such as gastroesophageal reflux disease, peptic ulcer disease, and Helicobacter pylori infection, and for the prevention of low-dose aspirin or nonsteroidal anti-inflammatory drug-induced peptic ulcers. Vonoprazan is a first-in-class potassium-competitive acid blocker, which has distinct advantages compared to other conventional proton pump inhibitors in terms of the efficacy for acid suppression. Due to its strong gastric acid suppression capabilities, vonoprazan serves as an effective drug for the treatment of gastroesophageal reflux disease and H. pylori infection.

Randomised clinical trial: vonoprazan versus lansoprazole for the initial relief of heartburn in patients with erosive oesophagitis

BACKGROUND

Proton pump inhibitors (PPIs) are widely used to treat gastro-oesophageal reflux disease (GORD). However, the onset of action is considered slow and PPIs cannot completely block acid secretion at night. A new potassium-competitive acid blocker (P-CAB) can rapidly block acid secretion. However, whether this P-CAB can relieve GORD symptoms quickly and adequately soon after starting treatment is unknown.

AIM

To determine how rapidly vonoprazan and lansoprazole provide heartburn relief.

METHODS

Patients (n = 32) with endoscopically confirmed erosive oesophagitis who experienced heartburn at least once a week were randomised in a double-blind manner to receive either daily vonoprazan (20 mg) or lansoprazole (30 mg) before breakfast for 14 days. Day time and night time heartburn were assessed daily throughout the study using a five-point Likert scale. The primary endpoint was the first day of complete day and night heartburn relief for at least seven consecutive days. The ethics committees of the participating institutions approved the study protocol.

RESULTS

Heartburn was relieved sooner with vonoprazan than with lansoprazole (P < 0.05, log-rank test). Heartburn was completely relieved in 31.3% and 12.5% of patients on day 1 with vonoprazan and lansoprazole, respectively. Significantly more patients achieved complete nocturnal heartburn relief with vonoprazan than lansoprazole (P < 0.01). Both regimens were well tolerated.

CONCLUSIONS

Complete sustained heartburn relief was achieved sooner with vonoprazan than with lansoprazole during the first week of therapy. (UMIN000018776).

Potassium-competitive acid blockers - are they the next generation of proton pump inhibitors?

The modern lifestyle caters to an increase in the incidence of peptic ulcer disease, gastroesophageal reflux disease and several other acid-related conditions of the gut. The drugs to prevent these conditions work either through H2 receptor blockade or inhibition of the H⁺, K⁺ ATPase enzyme. Although proton pump inhibitors have been proven to be efficacious, they have a slow onset of action with limited resolution of symptoms in most patients. Potassium-competitive acid blockers (P-CABs) are novel drugs that bind reversibly to K⁺ ions and block the H⁺, K⁺ ATPase enzyme, thus preventing acid production. P-CABs have a fast onset of action and have dose-dependent effects on acid production. Animal studies exist that differentiate the better results of P-CABs from proton pump inhibitors; further human trials will give a comprehensive picture of the results and will help to elucidate the therapeutic benefits of this new group of drugs.

Vonoprazan versus proton pump inhibitors for the management of gastroesophageal reflux disease: A protocol for a systematic review with meta-analysis

BACKGROUND AND AIM

Vonoprazan, a novel potassium-competitive acid blocking agent, is used in the management of gastroesophageal reflux disease (GERD). We aim to perform a systematic review and meta-analysis for the comparison of the effects of vonoprazan and proton pump inhibitors (PPIs) in GERD in randomized controlled trials (RCTs).

METHODS

A systematic and comprehensive search will be performed using MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), Google Scholar, and clinical trial registries, for studies published up to September 2018. Only randomized clinical trials will be included. Primary outcomes of symptoms and esophageal erosion improvement in the intention-to-treat analysis, and secondary outcomes of symptoms and esophageal erosion improvement rate in the per protocol analysis, the comparative efficacy in terms of healing rate of esophageal erosion on endoscopy, the comparative efficacy in terms of improvement of esophageal impedance-pH study, adverse events, long-term safety, and the comparative efficacy in terms of CYP2C19 metabolite levels will be studied. The quality of included studies will be assessed using the modified risk of bias tool. Heterogeneity of estimates across studies as well as publication bias will be assessed. This systematic review and meta-analysis will be performed according to the protocol recommended by the Cochrane Collaboration and reported according to the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines. All statistical analyses will be conducted using Stata SE version 15.0.

RESULTS

The results of this systematic review and meta-analysis will be published in a peer-reviewed journal.

CONCLUSION

To our knowledge, this systematic review and meta-analysis will be the first to evaluate existing research comparing Vonoprazan and PPIs in GERD. Our study will provide information about the effect of vonoprazan and PPIs in GERD in RCTs. The review will benefit patients, healthcare providers, and policymakers.

Potent Potassium-competitive Acid Blockers: A New Era for the Treatment of Acid-related Diseases

Conventional proton pump inhibitors (PPIs) are used as a first-line therapy to treat acid-related diseases worldwide. However, they have a number of limitations including slow onset of action, influence by cytochrome P450 polymorphisms, unsatisfactory effects at night, and instability in acidic conditions. Alternative formulations of conventional PPIs have been developed to overcome these problems; however, these drugs have only introduced small advantages for controlling acid secretion compared to conventional PPIs. Potassium-competitive acid blockers (P-CABs) were developed and have beneficial effects including rapid, long-lasting, and reversible inhibition of the gastric hydrogen potassium ATPase, the proton pump of the stomach. Vonoprazan was recently innovated as a novel, orally active P-CAB. It is currently indicated for the treatment of gastric and duodenal ulcers, reflux esophagitis, and prevention of low-dose aspirin- or nonsteroidal anti-inflammatory drug-related gastric and duodenal ulcer recurrence in Japan. Vonoprazan does not require enteric coating as it is acid-stable, and it can be taken without food because it is quickly absorbed. Vonoprazan accumulates in parietal cells under both acidic and neutral conditions. It does not require an acidic environment for activation, has long-term stability at the site of action, and has satisfactory safety and tolerability. Thus, vonoprazan may address the unmet medical need for the treatment of acid-related diseases.