Characteristics of the Novel Potassium-Competitive Acid Blocker Vonoprazan Fumarate (TAK-438)

Stability indicating HPTLC - densitometric method for estimation of vonoprazan fumarate

OBJECTIVES

High performance thin layer chromatography method was developed and validated for analysis of vonoprazan fumarate. An Alkaline forced degradation kinetic study was performed to find out probable rate of degradation of vonoprazan fumarate.

MATERIAL AND METHODS

Aluminum packed TLC plates precoated with silica gel 60 F 254 were used as stationary phase and Methanol: Toluene: triethylamine (6: 4: 0.1 v/v/v) was used as mobile phase. The detection was carried out at 267 nm wavelength as absorbance mode. HPTLC/MS analysis study was performed to detect alkaline degradant.

RESULTS

A compact band (Rf value of 0.43 ± 0.1) was obtained for vonoprazan fumarate. Regression analysis shows a good linear relationship (R2 = 0.9996) between peak area and concentration in the range 200-1200 ng/band. The accuracy determined by standard addition method for vonoprazan fumarate and percentage recovery was found to be 99.72% - 101.74%. Forced degradation stability study was performed under different stress conditions including hydrolytic, oxidative, thermal and photolytic. Degradation was observed under alkaline condition and it was found to follow first order degradation kinetic. The possible structure of base degradants was also determined using HPTLC-MS analysis. The method was successfully applied for the estimation of drug in synthetic mixture.

CONCLUSION

A New, Simple, precise and accurate method has been developed and validated for the quantification of vonoprazan fumarate. Forced degradation studies were performed. The method can be used for quality control and stability sample evaluation of vonoprazan fumarate.

Current research status and trends of potassium-competitive acid blockers in the treatment of acid-related diseases: a bibliometric analysis

Objective

To explore the current research status and trends of potassium-competitive acid blockers (P-CABs) in the treatment of acid related diseases (ARDs) using bibliometric analysis.

Materials and methods

We collected publications related to P-CAB in the treatment of acid-related diseases in the Web of Science (WOS) Core Collection from the establishment of the database to 30 June 2024. We evaluated the publication volume and citation status over the years using the WOS platform, and visualized the authors, countries, institutions, keywords, and citations of the publications using CiteSpace and VOSviewer.

Results

This study included a total of 455 articles. The number of publications and citations related to research has been increasing year by year. The results show that the scholars with the highest number of publications mainly come from South Korea and Japan. Scholars such as Geun Seog Song, Bongtae Kim, and Nobuhiro Inatomi produced many works in related fields. The most popular drug in this field was vonoprazan, and research on this drug mainly focused on the effectiveness and safety evaluation of ARDs such as Helicobacter pylori infection, gastroesophageal reflux disease, peptic ulcers, etc. Researchers were concerned about the evaluation of treatment regimens and efficacy comparison between P-CABs and traditional proton pump inhibitors (PPIs) in the treatment of ARDs. At the same time, researchers are also closely monitoring the potential adverse reactions and long-term adverse outcomes of clinical application of P-CABs for ARDs.

Conclusion

The clinical application of P-CABs, represented by vonoprazan, in ARDs is receiving widespread attention from researchers. The exploration of the application of this type of drug in ARDs is constantly expanding, and it is a research field with great clinical value and research potential.

Safety of potassium-competitive acid blockers in the treatment of gastroesophageal reflux disease

INTRODUCTION

Proton pump inhibitors (PPIs) are the first-line treatment for gastroesophageal reflux disease (GERD). However, due to their intrinsic limitations, there are still unmet clinical needs that have fostered the development of potassium-competitive acid blockers (P-CABs). Currently, four different drugs (vonoprazan, tegoprazan, fexuprazan, and keverprazan) are marketed in some Asian countries, whereas only vonoprazan and tegoprazan are available in Western countries (USA and Brazil or Mexico, respectively).

AREAS COVERED

This review summarizes the current knowledge on P-CABs acute and long-term safety in GERD treatment compared to that of PPIs. Full-text articles and abstracts were searched in PubMed.

EXPERT OPINION

P-CABs proved to address some of the unmet clinical needs in GERD, with a favorable risk-benefit ratio compared to conventional PPIs. Preclinical and clinical findings have highlighted P-CAB safety to be superimposable, to that of PPIs, in short-term treatments, although further studies are warranted to monitor their effects in long-term therapy. From an epidemiological point of view, the paucity of rigorous data for many variables (e.g. age, ethnicity, drug interactions, comorbidities, genetic polymorphisms, interindividual susceptibility, and gut dysbiosis) deserves a worldwide framework of continuous pre/post-marketing pharmacovigilance programs to reduce potential confounding factors and accurately link acute and chronic P-CAB therapy to adverse outcomes.

Diagnosis and Treatment of Gastroesophageal Reflux Disease (Clinical Guidelines of the Russian Gastroenterological Association, Russian Scientific Medical Society of Internal Medicine, Russian Society for the Prevention of Noncommunicable Diseases, Scientific Community for Human Microbiome Research)

Aim. These recommendations are developed for practitioners in order to familiarize them with modern diagnostic methods, management features and pharmacotherapy of patients with gastroesophageal reflux disease (GERD).

General provisions. GERD is the most common reason for patients to visit clinics. There are esophageal and extraesophageal manifestations of GERD. Patients' complaints of heartburn and regurgitation remain the most sensitive and specific clinical manifestations of GERD. The diagnosis of GERD is established on the basis of anamnestic data, instrumental examination (detection of reflux esophagitis during upper gastrointestinal endoscopy, detection of pathological gastroesophageal reflux with 24-hour pH-metry or/and 24-hour pH-impedance monitoring). Patients with suspected GERD and the absence of erosive and ulcerative changes in the mucous membrane of the esophagus or the presence of erosive esophagitis of Grade A according to Los Angeles Classification of Gastroesophageal Reflux Disease are recommended to conduct 24-hour pH-metry on PPI off to exclude or confirm the diagnosis of GERD. Patients with extraesophageal manifestations of GERD without classic symptoms (heartburn, regurgitation) are recommended to undergo 24-hour pH-impedance monitoring with discontinuation of proton pump inhibitor therapy. When deciding on surgical treatment, all patients need to perform high-resolution esophageal manometry and 24-hour pH-impedance monitoring. Complications of GERD include bleeding, strictures, Barrett’s esophagus and esophageal adenocarcinoma. The main groups of medications used in the treatment of GERD are proton pump inhibitors (PPIs), potassium-competitive acid blockers (P-CABs), alginates, antacids, and prokinetics. PPIs are the drugs of choice in the treatment of both symptoms of gastroesophageal reflux disease and existing erosive esophagitis. Combination therapy Rebamipide with PPIs increases the effectiveness of relief of GERD symptoms, as well as reduces the frequency of relapses.

Conclusion. These clinical recommendations will improve the quality of medical care for patients with GERD.

The efficacy and safety of a simple 14-day vonoprazan-minocycline dual therapy for Helicobacter pylori eradication: a retrospective pilot study

Background

Current eradication regimens are not ideal for Helicobacter pylori infected patients who have difficulty choosing antibiotics due to penicillin allergy or antibiotic resistance.

Objective

To explore the efficacy and safety of a simple vonoprazan-minocycline dual therapy (VM dual therapy) in H. pylori eradication.

Design

Clinical data of patients who were prescribed 14-day VM dual therapy were retrospectively collected. The included patients were 18-70 years old and positive for 13C urea breath test (13C-UBT). They were allergic to penicillin or had a history of repeated antibiotic exposure or had failed eradication with multiple regimens containing amoxicillin. VM dual therapy consists of vonoprazan 20 mg twice daily and minocycline 100 mg twice daily. 13C-UBT was repeated 4-6 weeks after treatment to evaluate the therapeutic outcome.

Results

Of the 88 enrolled patients, 54 were treatment naïve, 13 had one prior eradication failure, and 21 had multiple eradication failures. The overall intention to treat (ITT) and per-protocol (PP) eradication rates were 90.9% (95% CI: 82.4-95.7) and 95.2% (95% CI: 87.6-98.5). The ITT eradication rates were 90.7% (95% CI: 78.9-96.5) in treatment-naïve patients, 84.6% (95% CI: 53.7-97.3) in patients with one prior treatment failure, and 95.2% (95% CI: 74.1-99.8) in patients with multiple failures. The PP eradication rates were 94.2% (95% CI: 83.1-98.5), 91.7% (95% CI: 59.8-99.6), and 100%, respectively. The overall incidence of adverse events was 23.0%. The common adverse reactions were nausea and mild dizziness, which could be resolved without intervention.

Conclusion

Simple VM dual therapy exhibited a good eradication rate, low incidence of adverse effects, and good adherence. It is a potential new regimen for both first-line and rescue therapy.

A comprehensive review of new small molecule drugs approved by the FDA in 2022: Advance and prospect

In 2022, the U.S. Food and Drug Administration approved a total of 16 marketing applications for small molecule drugs, which not only provided dominant scaffolds but also introduced novel mechanisms of action and clinical indications. The successful cases provide valuable information for optimizing efficacy and enhancing pharmacokinetic properties through strategies like macrocyclization, bioequivalent group utilization, prodrug synthesis, and conformation restriction. Therefore, gaining an in-depth understanding of the design principles and strategies underlying these drugs will greatly facilitate the development of new therapeutic agents. This review focuses on the research and development process of these newly approved small molecule drugs including drug design, structural modification, and improvement of pharmacokinetic properties to inspire future research in this field.

Efficacy and safety of tegoprazan for duodenal ulcers in Chinese patients: a multicenter, randomized, double-blind, non-inferiority, phase III study

OBJECTIVE

Tegoprazan represents a newly developed potassium-competitive acid blocker utilized for the treatment of acid-related disorders. The present study aimed to explore the therapeutic effectiveness of tegoprazan in Chinese individuals with duodenal ulcers (DU).

METHODS

In the current multicenter, randomized, double-blind, double-dummy, parallel-group, non-inferiority, phase III clinical trial, individuals with DU underwent randomization 1:1 to be administered tegoprazan 50 mg or lansoprazole 30 mg once daily. The primary efficacy endpoint was the 6-week cumulative endoscopic ulcer healing rate. Secondary endpoints included 4-week endoscopic ulcer healing rate and relief of DU-related gastrointestinal symptoms at weeks 2, 4, and 6. Safety analysis encompassed adverse events (AEs) and laboratory indexes.

RESULTS

The 6-week cumulative endoscopic ulcer healing rates were 96.9% (188/194) and 99.0% (189/191) in the tegoprazan and lansoprazole groups, respectively, indicating a difference of -2.0% (95% confidence interval (CI) = -4.9 to 0.8) in the full analysis set (FAS). The corresponding healing rates were 98.4% (185/188) and 99.5% (183/184) in the per-protocol set, respectively, indicating a difference of -1.1% (95% CI = -3.1 to 1.0). The 4-week healing rates in the tegoprazan and lansoprazole groups were 89.2% (173/194) and 88.5% (169/191) in the FAS, respectively, with a difference of 0.7% (95% CI = -5.6 to 7.0). Treatment-related AEs, all mild-to-moderate, were reported in 38.2% (78/204) and 48.2% (94/195) of participants in the tegoprazan and lansoprazole groups, respectively.

CONCLUSIONS

Tegoprazan 50 mg once daily is effective and non-inferior to lansoprazole 30 mg once daily in Chinese patients with DU, showing a promising safety and tolerability profile.

CLINICALTRIALS.GOV REGISTRATION NUMBER

NCT05010954.

Human F-ATP synthase as a drug target

Practical and conceptual barriers have kept human F-ATP synthase out of reach as a target for the treatment of human diseases. Although this situation has persisted for decades, it may change in the near future. In this review the principal functionalities of human F-ATP synthase--proton motive force / ATP interconversion, membrane bending and mitochondrial permeability transition--are surveyed in the context of their respective potential for pharmaceutical intervention. Further, the technical requirements necessary to allow drug designs that are effective at the multiple levels of functionality and modality of human F-ATP synthase are discussed. The structure-based development of gastric proton pump inhibitors is used to exemplify what might be feasible for human F-ATP synthase. And finally, four structural regions of the human F-ATP synthase are examined as potential sites for the development of structure based drug development.

Potassium-competitive Acid Blockers: Current Clinical Use and Future Developments

PURPOSE OF THE REVIEW

Acid suppression with proton pump inhibitors (PPIs) represents the standard of care in the treatment of acid-related diseases. However, despite their effectiveness, PPIs display some intrinsic limitations, which underlie the unmet clinical needs that have been identified over the past decades. The aims of this review are to summarize the current status and future development of the new class of antisecretory drugs (potassium-competitive acid blockers, P-CABs) that have recently been introduced into medical practice.

RECENT FINDINGS

Over the past decades, clinical needs unmet by the current acid suppressants have been recognized, especially in the management of patients with GERD, Helicobacter pylori infection and NSAID-related peptic ulcer. The failure to address these needs is mainly due to their inability to achieve a consistent acid suppression in all patients and, particularly, to control nighttime acidity. It was then realized that an extended duration of acid suppression would exert additional benefits. The available data with P-CABs show that they are able to address these unmet clinical needs. Four different P-CABs (vonoprazan, tegoprazan, fexuprazan and keverprazan) are currently available. However, only two of them are approved outside Asia. Vonoprazan is available in North, Central and South America while tegoprazan is marketed only in Latin American countries. Two other compounds (namely linazapran glurate and zestaprazan) are presently under clinical development. While clinical trials on GERD have been performed with all P-CABs, only vonoprazan and tegoprazan have been investigated as components of Helicobacter pylori eradication regimens. The available data show that-in the above two clinical indications-P-CABs provide similar or better efficacy in comparison with PPIs. Their safety in the short-term overlaps that of PPIs, but data from long-term treatment are needed.

Vonoprazan-Associated Mucosal Redness: A Report of Two Cases

Vonoprazan, a potassium-competitive acid blocker, is effective at treating acid-related gastrointestinal disorders but has been linked to gastric mucosal redness, a novel condition. This report describes two cases of vonoprazan-associated mucosal redness. Case 1 involved a 73-year-old woman who developed longitudinal erythema and mild mucosal changes after starting vonoprazan seven years ago. Case 2 involved a 70-year-old man who exhibited significant erythema and atrophic gastritis after seven months of treatment. In both cases, the pathological findings included hemorrhage in the superficial mucosa, highlighting that microhemorrhage may be the corresponding pathological finding for vonoprazan-associated mucosal redness.

Advanced interpenetrating polymer networks for innovative gastroretentive formulations targeting Helicobacter pylori gastric colonization

The escalating challenges of Helicobacter pylori-induced gastric complications, driven by rising antibiotic resistance and persistent cancer risks, underscore the demand for innovative therapeutic strategies. This study addresses this urgency through the development of tailored semi-interpenetrating polymer networks (semi-IPN) serving as gastroretentive matrices for amoxicillin (AMOX). They are biodegradable, absorb significant volume of simulated gastric fluid (swelling index > 360 %) and exhibit superporous microstructures, remarkable mucoadhesion, and buoyancy. The investigation includes assessment at pH 1.2 for comparative analysis with prior studies and, notably, at pH 5.0, reflecting the acidic environment in H. pylori-infected stomachs. The semi-IPN demonstrated gel-like structures, maintaining integrity throughout the 24-hour controlled release study, and disintegrating upon completing their intended function. Evaluated in gastroretentive drug delivery system performance, AMOX release at pH 1.2 and pH 5.0 over 24 h (10 %-100 %) employed experimental design methodology, elucidating dominant release mechanisms. Their mucoadhesive, buoyant, three-dimensional scaffold stability, and gastric biodegradability make them ideal for accommodating substantial AMOX quantities. Furthermore, exploring the inclusion of the potassium-competitive acid blocker (P-CAB) vonoprazan (VONO) in AMOX-loaded formulations shows promise for precise and effective drug delivery. This innovative approach has the potential to combat H. pylori infections, thereby preventing the gastric cancer induced by this pathogen.

Absorption, distribution, metabolism and excretion of linaprazan glurate in rats

Linaprazan (AZD0865, TX07) is one of potassium-competitive acid blockers. However, linaprazan is rapidly excreted from the body, shortening its acid inhibition property. Linaprazan glurate (X842) is a prodrug of linaprazan with a prolonged inhibitory effect on gastric acid secretion. Linaprazan glurate has entered clinical trials, but few studies have reported its metabolism in non-clinical and clinical settings. In this study, we studied the pharmacokinetics, tissue distribution, mass balance, and metabolism of linaprazan glurate in rats after a single oral dose of 2.4 mg/kg (100 µCi/kg) [14C]linaprazan glurate. The results demonstrated that linaprazan glurate was mainly excreted via feces in rats with 70.48% of the dose over 168 h. The plasma AUC0-∞ of linaprazan glurate in female rats was 2 times higher than that in male rats. Drug-related substances were mainly concentrated in the stomach, eyes, liver, small intestine, and large intestine after administration. In blood, drug-related substances were mostly distributed into plasma instead of hemocytes. In total, 13 metabolites were detected in rat plasma, urine, feces, and bile. M150 (2,6-dimethylbenzoic acid) was the predominant metabolite in plasma, accounting for 80.65% and 67.65% of AUC0-24h in male and female rats, respectively. Based on the structures, linaprazan glurate was mainly hydrolyzed into linaprazan, followed by a series of oxidation, dehydrogenation, and glucuronidation in rats. Besides, CES2 is the main metabolic enzyme involved in the hydrolysis of linaprazan glurate to linaprazan.

P-CAB versus PPI in the eradication of Helicobacter pylori: a systematic review and network meta-analysis

Background

The efficacy and safety of potassium-competitive acid blockers (P-CABs) in the eradication of Helicobacter pylori (Hp) remains controversial when compared with proton pump inhibitors (PPIs).

Objectives

The current study set out to compare the differences in the eradication rate and adverse reactions between eradication regimens based on P-CAB or PPI drugs and the differences between the vonoprazan-based and the tegoprazan-based regimens to explore the efficacy and safety of different Hp eradication regimens.

Data sources and methods

Databases including PubMed, EMBASE, Cochrane Library, and WOS were searched from the inception of these databases up to July 2023, and eligible randomized controlled trials (RCTs) were included. The outcome measures were the eradication rate and the incidence of adverse reactions of different regimens in treating Hp. The results were estimated as relative risk (RR) and its 95% confidence interval (CI), and R 4.2.1 software was used to perform the network meta-analysis (NMA).

Results

A total of 20 studies were included in the analysis, involving 5815 patients with Hp. In terms of eradication rate, the 2-week vonoprazan-based triple regimen (V-Tri-2w) was the best, which was superior to the 2-week PPI-based quadruple regimen [P-Qua-2w, RR = 0.9, 95% CI: (0.85-0.95)] and the 1-week tegoprazan-based triple regimen [T-Tri-1w, RR = 0.79, 95% CI: (0.64-0.97)]; the 2-week tegoprazan-based quadruple regimen (T-Qua-2w) was superior to the 1-week PPI-based triple regimen [P-Tri-1w, RR = 0.82, 95% CI: (0.67-0.99)], and there was no difference between the remaining tegoprazan-based regimens and the PPI-based or vonoprazan-based regimens. In terms of the incidence of adverse reactions, the 2-week vonoprazan-based binary regimen (V-Bi-2w) was lower than that of the 2-week PPI-based quadruple regimen [P-Qua-2w, RR = 1.98, 95% CI: (1.57-2.52)]; there was no significant difference between 1 and 2 weeks for each regimen, such as the vonoprazan-based triple regimen [RR = 1.11, 95% CI: (0.82-1.52)].

Conclusion

In the eradication treatment of Hp, the efficacy and safety of vonoprazan-based regimens are generally better than those of PPI-based regimens. Among them, the V-Tri-2w regimen has the highest eradication rate and may be the preferred choice for Hp eradication.

Acid-suppressive drugs: A systematic review and network meta-analysis of their nocturnal acid-inhibitory effect

BACKGROUND AND AIMS

Acid-suppressive drugs (ASDs) are widely used in many gastric acid-associated diseases. Nocturnal acid breakthrough has been a common problem of many ASDs, such as proton-pump inhibitors (PPIs) and H2 -receptor antagonists (H2RAs). Potassium-competitive acid blockers (P-CABs) are expected to solve this continuing conundrum. This article examined major ASDs and compared them with placebo in terms of nocturnal acid-inhibitory effects, using a network meta-analysis of randomized controlled trials (RCTs).

METHODS

To compare the effectiveness of major ASDs, a Bayesian network meta-analysis (NMA) was applied to process data extracted from RCTs. The plausible ranking for each regimen and some subgroups were assessed by surface under the cumulative ranking curves (SUCRA).

RESULTS

Fifty-five RCTs were conducted with 2015 participants. In terms of nocturnal acid-inhibitory effects, the overall results showed that tegoprazan (SUCRA 91.8%) and vonoprazan (SUCRA 91.0%) had the best performance, followed by new PPIs (including tenatoprazole and ilaprazole) (SUCRA 76.6%), additional H2RAs once at bedtime (AHB) (SUCRA 61.3%), isomer PPIs (including esomeprazole and dexlansoprazole) (SUCRA 38.6%), revaprazan (SUCRA 34.7%), traditional PPIs (including omeprazole, rabeprazole, pantoprazole, lansoprazole) (SUCRA 32.6%), H2RAs (SUCRA 23.1%), and placebo (SUCRA 0.3%). In some subgroups, the nocturnal acid-inhibitory effect of vonoprazan or tegoprazan was better than most of the other regimens, even new PPIs and AHB.

CONCLUSIONS

This is the first study to compare the effect of ASDs on inhibiting nocturnal acid breakthrough. Overall, in terms of nocturnal acid-inhibitory effect, vonoprazan and tegoprazan had an advantage against other regimens including H2RAs, isomer PPIs, traditional PPIs, AHB, and new PPIs. Even in some subgroups, such as language classification (English), types of study design (crossover-RCT), age (≤40 years), BMI (18.5-24.9 kg/m2 ), continent (Asia and North America), disease status (health), the duration of therapy (2 weeks), and time of administration (at daytime or at night-time), the nocturnal acid-inhibitory effect of vonoprazan or tegoprazan were better than most regimens, even AHB and new PPIs.

Deep learning driven de novo drug design based on gastric proton pump structures

Existing drugs often suffer in their effectiveness due to detrimental side effects, low binding affinity or pharmacokinetic problems. This may be overcome by the development of distinct compounds. Here, we exploit the rich structural basis of drug-bound gastric proton pump to develop compounds with strong inhibitory potency, employing a combinatorial approach utilizing deep generative models for de novo drug design with organic synthesis and cryo-EM structural analysis. Candidate compounds that satisfy pharmacophores defined in the drug-bound proton pump structures, were designed in silico utilizing our deep generative models, a workflow termed Deep Quartet. Several candidates were synthesized and screened according to their inhibition potencies in vitro, and their binding poses were in turn identified by cryo-EM. Structures reaching up to 2.10 Å resolution allowed us to evaluate and re-design compound structures, heralding the most potent compound in this study, DQ-18 (N-methyl-4-((2-(benzyloxy)-5-chlorobenzyl)oxy)benzylamine), which shows a Ki value of 47.6 nM. Further high-resolution cryo-EM analysis at 2.08 Å resolution unambiguously determined the DQ-18 binding pose. Our integrated approach offers a framework for structure-based de novo drug development based on the desired pharmacophores within the protein structure.

Efficacy and safety of vonoprazan-amoxicillin dual therapy for Helicobacter pylori first-line treatment: a single-center, randomized, controlled trial

Background

With the increase in antibiotic resistance, the success rate of Helicobacter pylori (H. pylori) eradication therapy has declined in recent years. Vonoprazan-amoxicillin (VA) dual therapy has been reported to be a promising regimen.

Objectives

To compare the efficacy and safety of VA dual therapy and bismuth quadruple therapy containing amoxicillin and clarithromycin for H. pylori first-line eradication, and to further analyze the effects of clarithromycin resistance on eradication rate.

Design

This study was a single-center, open-label, randomized controlled trial.

Methods

Treatment-naïve H. pylori-infected patients were randomly allocated 1:1 to the VA group (vonoprazan 20 mg twice daily and amoxicillin 750 mg four times daily, for 14 days) or the RBAC group (rabeprazole 10 mg, bismuth potassium citrate 220 mg, amoxicillin 1000 mg and clarithromycin 500 mg twice daily, for 14 days). H. pylori clarithromycin resistance and CYP2C19 gene polymorphisms were detected with real-time polymerase chain reaction (PCR) technique. The eradication rates and adverse events were analyzed.

Results

A total of 151 patients were enrolled. The intention-to-treat (ITT), modified intention-to-treat (mITT), and per-protocol (PP) eradication rates and their 95% confidence intervals (95% CIs) were 94.6% (86.0-98.3%), 98.6% (91.3-99.9%), and 98.5% (90.9-99.9%) for VA group and 87.0% (77.0-93.3%), 91.8% (82.3-96.6%), and 93% (83.7-97.4%) for RBAC group. The eradication rate of the VA group was noninferior to the RBAC group in ITT, mITT, and PP analyses (p < 0.0001). In patients infected with strains of clarithromycin resistance point mutation, the eradication rate of the RBAC group decreased to lower than 90%, but the difference from the VA group did not achieve statistical significance (ITT eradication rate: 81.5% in the RBAC group and 96.2% in the VA group, p = 0.192). The incidence of adverse events in the VA group was 39.2%, which was significantly lower than that in the RBAC group (79.2%, p = 0.000).

Conclusion

The efficacy of VA dual therapy is noninferior to RBAC in H. pylori first-line eradication, with fewer adverse reactions.

Registration

This study was registered at the Chinese Clinical Trial Registry (ChiCTR2100052550) on 30 October 2021.

Discovery of novel benzimidazole derivatives as potent potassium-competitive acid blockers for the treatment of acid-related diseases

H⁺, K⁺-ATPase, as the most critical enzyme in gastric acid secretion, has long been an attractive target for the treatment of acid-related diseases. In this study, a series of benzimidazole derivatives were designed and synthesized through conformational restriction and skeleton hopping strategies by using vonoprazan as the lead compound. Among them, compounds A12 (IC₅₀ = 9.32 μM) and A18 (IC₅₀ = 5.83 μM) showed better inhibition at the enzyme level. In addition, gastric acid secretion inhibition was assessed in vivo, and the results showed that A12 and A18 significantly inhibited basal gastric acid secretion, 2-deoxy-d-glucose (2DG) stimulated gastric acid secretion and histamine-stimulated gastric acid secretion. In further in vitro metabolic experiments, A12 and A18 demonstrated excellent stability and low toxicity. Pharmacokinetic studies showed that the p.o. and i.v. half-lives of A18 were 3.21 h and 8.67 ± 1.15 h, respectively. In summary, A18 might be a novel and effective potassium-competitive acid blocker, and this study provides strong support for it use in the treatment of acid-related diseases.

Distribution- and Metabolism-Based Drug Discovery: A Potassium-Competitive Acid Blocker as a Proof of Concept

Conventional methods of drug design require compromise in the form of side effects to achieve sufficient efficacy because targeting drugs to specific organs remains challenging. Thus, new strategies to design organ-specific drugs that induce little toxicity are needed. Based on characteristic tissue niche-mediated drug distribution (TNMDD) and patterns of drug metabolism into specific intermediates, we propose a strategy of distribution- and metabolism-based drug design (DMBDD); through a physicochemical property-driven distribution optimization cooperated with a well-designed metabolism pathway, SH-337, a candidate potassium-competitive acid blocker (P-CAB), was designed. SH-337 showed specific distribution in the stomach in the long term and was rapidly cleared from the systemic compartment. Therefore, SH-337 exerted a comparable pharmacological effect but a 3.3-fold higher no observed adverse effect level (NOAEL) compared with FDA-approved vonoprazan. This study contributes a proof-of-concept demonstration of DMBDD and provides a new perspective for the development of highly efficient, organ-specific drugs with low toxicity.

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.

Influence of daily versus alternate-day dosing of vonoprazan on intragastric pH, serum gastrin, and the antiplatelet function of clopidogrel : Influence of alternate-day dosing of vonoprazan

BACKGROUND

Vonoprazan, a potassium-competitive acid blocker, inhibits gastric acid secretion and attenuates the antiplatelet function of clopidogrel more potently than esomeprazole. We investigated whether alternate-day dosing of vonoprazan might avoid this interaction with clopidogrel while providing sufficient gastric acid inhibition.

METHODS

Following 24 h of pH monitoring (control regimen), 12 healthy volunteers received three regimens (clopidogrel-only regimen: clopidogrel 75 mg daily [q.d.]; vonoprazan alternate-day regimen: vonoprazan 10 mg every other day [q.o.d.] + clopidogrel 75 mg q.d.; vonoprazan daily regimen: vonoprazan 10 mg q.d. + clopidogrel 75 mg q.d.) for 14 days in a randomized open-label crossover manner. Intragastric pH monitoring was performed for 24 h on day 13 in the clopidogrel-only and vonoprazan q.d. regimens and for 48 h on days 13 and 14 in the vonoprazan q.o.d. regimen. Serum gastrin and inhibition of platelet aggregation (IPA) were measured before the commencement of pH monitoring in each regimen.

RESULTS

Twelve volunteers completed the study. Equivalent median IPA values in the q.o.d. and q.d. regimens were measured (21.8% and 25%, respectively) and were significantly lower than that with the clopidogrel-only regimen (40.8%). The median pH4 holding time ratio for the vonoprazan q.o.d. regimen (49.7%) was superior to that of the clopidogrel-only regimen (18.4%), but was significantly inferior to that of the vonoprazan q.d. regimen (77.0%; p < 0.01).

CONCLUSION

Alternate-day administration of vonoprazan could not prevent the interaction between vonoprazan and clopidogrel, and acid inhibition was inferior to that with vonoprazan daily administration. Alternate-day administration of vonoprazan thus appears to be of questionable clinical utility.

Co-Administration of Vonoprazan, Not Tegoprazan, Affects the Pharmacokinetics of Atorvastatin in Healthy Male Subjects

Potassium-competitive acid blocker is a new class of drugs inhibiting gastric acid. It is controversial that vonoprazan showed the inhibitory activities of cytochrome P450 3A4. This study aimed to evaluate the pharmacokinetics (PK) of atorvastatin and safety when atorvastatin was administered alone and co-administered with vonoprazan or tegoprazan. An open-label, multiple-dose, 3-intervention, 4-sequence, 4-period, partial replicate crossover study was conducted, and three interventions were; one is orally administered atorvastatin 40 mg alone once daily for 7 days, another is atorvastatin co-administered with vonoprazan 20 mg, and the other is atorvastatin co-administered with tegoprazan 50 mg. PK blood samples were collected up to 24 h after the last dose, and PK parameters for atorvastatin, 2-hydroxyatorvastatin and atorvastatin lactone were estimated by a non-compartmental method. Safety was evaluated, including adverse events and clinical laboratory tests. A total of 28 subjects completed the study. When atorvastatin was co-administered with vonoprazan, the systemic exposures of atorvastatin and atorvastatin lactone significantly increased, and the metabolic ratio of 2-hydroxyatorvastatin significantly decreased. Hypergastrinemia only occurred when atorvastatin was co-administered with vonoprazan. However, the plasma concentration profiles of atorvastatin, 2-hydroxyatorvastatin and atorvastatin lactone were similar when atorvastatin was administered alone or co-administered with tegoprazan. In conclusion, after multiple doses of atorvastatin co-administered with vonoprazan in healthy subjects, the systemic exposure of atorvastatin and the incidence of hypergastrinemia increased. With tegoprazan, however, those interactions were not observed.

Gastric proton pump with two occluded K+ engineered with sodium pump-mimetic mutations

The gastric H⁺,K⁺-ATPase mediates electroneutral exchange of 1H⁺/1K⁺ per ATP hydrolysed across the membrane. Previous structural analysis of the K⁺-occluded E2-P transition state of H⁺,K⁺-ATPase showed a single bound K⁺ at cation-binding site II, in marked contrast to the two K⁺ ions occluded at sites I and II of the closely-related Na⁺,K⁺-ATPase which mediates electrogenic 3Na⁺/2K⁺ translocation across the membrane. The molecular basis of the different K⁺ stoichiometry between these K⁺-counter-transporting pumps is elusive. We show a series of crystal structures and a cryo-EM structure of H⁺,K⁺-ATPase mutants with changes in the vicinity of site I, based on the structure of the sodium pump. Our step-wise and tailored construction of the mutants finally gave a two-K⁺ bound H⁺,K⁺-ATPase, achieved by five mutations, including amino acids directly coordinating K⁺ (Lys791Ser, Glu820Asp), indirectly contributing to cation-binding site formation (Tyr340Asn, Glu936Val), and allosterically stabilizing K⁺-occluded conformation (Tyr799Trp). This quintuple mutant in the K⁺-occluded E2-P state unambiguously shows two separate densities at the cation-binding site in its 2.6 Å resolution cryo-EM structure. These results offer new insights into how two closely-related cation pumps specify the number of K⁺ accommodated at their cation-binding site.

The gastric H⁺,K⁺-ATPase is a proton pump that creates the acidic environment of the stomach lumen, maintaining high proton gradient across the gastric mucosa cell membrane. Here, structural analysis of rationally designed H⁺,K⁺-ATPase mutants provides insight into this and other P-type ATPases cation binding stoichiometry and mechanisms.

Clinical significance of P-class pumps in cancer

P-class pumps are specific ion transporters involved in maintaining intracellular/extracellular ion homeostasis, gene transcription, and cell proliferation and migration in all eukaryotic cells. The present review aimed to evaluate the role of P-type pumps [Na+/K+ ATPase (NKA), H+/K+ ATPase (HKA) and Ca2+-ATPase] in cancer cells across three fronts, namely structure, function and genetic expression. It has been shown that administration of specific P-class pumps inhibitors can have different effects by: i) Altering pump function; ii) inhibiting cell proliferation; iii) inducing apoptosis; iv) modifying metabolic pathways; and v) induce sensitivity to chemotherapy and lead to antitumor effects. For example, the NKA β2 subunit can be downregulated by gemcitabine, resulting in increased apoptosis of cancer cells. The sarcoendoplasmic reticulum calcium ATPase can be inhibited by thapsigargin resulting in decreased prostate tumor volume, whereas the HKA α subunit can be affected by proton pump inhibitors in gastric cancer cell lines, inducing apoptosis. In conclusion, the present review highlighted the central role of P-class pumps and their possible use and role as anticancer cellular targets for novel therapeutic chemical agents.

Evaluations of Gastric Acid Pocket Using Novel Vertical 8-Channel pH Monitoring System and Effects of Acid Secretion Inhibitors

Background/Aims

The gastric acid pocket has an important role in gastroesophageal reflux disease development. In this study, we utilized a novel 8-channel pH monitoring system with sensor intervals of 1 cm on the vertical axis for evaluation of postprandial gastric acid pocket in healthy Japanese adults, as well as the effects of vonoprazan and rabeprazole.

Methods

Twelve healthy volunteers without Helicobacter pylori infection were enrolled. A catheter was inserted transnasally and positioned under X-ray guidance, then postprandial acid pocket formation was monitored over time in a sitting position. Thereafter, acid pocket changes were assessed following administration of vonoprazan (20 mg) or rabeprazole (20 mg).

Results

The gastric acid pocket was successfully measured by use of the present system in 10 cases, while failure occurred in 2 because of inappropriate catheter positioning. Observed acid pockets were visualized with a mean length of 2.2 ± 0.4 channels on the top layer of food contents approximately 20 minutes after finishing a meal. There were some variations for lasting time of the acid pocket. Complete elimination within 3 hours after administration of vonoprazan was noted in all cases. Likewise, following administration of rabeprazole, the acid pocket was eliminated in 7 cases, while acidity was reduced though the pocket remained observable in 3.

Conclusions

Gastric acid pocket observations were possible using our novel vertical 8-channel sensor catheter. The present findings showed that vonoprazan strongly suppressed acid secretion within a short period, suggesting its effectiveness for gastroesophageal reflux disease treatment.

Evaluation of safety and pharmacokinetics of bismuth-containing quadruple therapy with either vonoprazan or lansoprazole for Helicobacter pylori eradication

Aims

Helicobacter pylori (Hp) eradication plays a key role in the treatment and prevention of peptic ulcer diseases. Increasing clarithromycin resistance in Hp necessitates more effective treatments for eradication, such as bismuth‐containing quadruple therapy. We aimed to compare the safety and pharmacokinetics (PK) of bismuth between vonoprazan‐ and lansoprazole‐containing quadruple therapy in Hp‐positive subjects.

Methods

In this randomised, double‐blind, parallel‐group study, Hp‐positive subjects were randomised to receive vonoprazan‐ or lansoprazole‐containing quadruple therapy. Each subject received vonoprazan 20 mg or lansoprazole 30 mg combined with bismuth 220 mg, clarithromycin 500 mg and amoxicillin 1000 mg twice daily for 14 days. Blood sampling and urine collection for bismuth PK were conducted predose and up to 12 hours postdose at steady‐state. The PK parameters of bismuth were derived using a noncompartmental method and compared between treatments. An exploratory breath test for Hp was conducted at screening and at the follow‐up visit on day 42. Safety was assessed by adverse event monitoring, physical examinations, vital signs, 12‐lead electrocardiograms and clinical laboratory tests.

Results

A total of 30 subjects were randomised and 26 subjects completed the study (12 in the vonoprazan group and 14 in the lansoprazole group). The systemic exposure of bismuth in the 2 treatments was comparable (~5% difference). All subjects turned negative for Hp at the follow‐up visit. No significant difference in safety profiles was noted between the 2 treatments.

Conclusion

The systemic exposure of bismuth was similar between vonoprazan‐ and lansoprazole‐containing quadruple therapy. Vonoprazan‐containing quadruple therapy was safe and well tolerated.

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.

Predictors for development of denosumab-induced hypocalcaemia in cancer patients with bone metastases determined by ordered logistic regression analysis

This retrospective study was undertaken to identify predictors for the development of hypocalcaemia even with prophylactic administration of calcium and vitamin D, and to help guide future strategies to improve the safety, efficacy, and QOL of patients receiving denosumab. Between January 2016 and February 2020, a total of 327 advanced cancer patients at our hospital who were receiving denosumab were enrolled. Variables associated with the development of hypocalcaemia were extracted from the clinical records. The level of hypocalcaemia was evaluated using CTCAE version 5. Multivariate ordered logistic regression analysis was performed to identify predictors for the development of hypocalcaemia. Optimal cut off thresholds were determined using ROC analysis. Values of P < 0.05 (2-tailed) were considered significant. 54 patients have developed hypocalcemia (≥ Grade 1). Significant factors identified included concomitant use of vonoprazan [odds ratio (OR) = 3.74, 95% confidence interval (CI) 1.14–12.26; P = 0.030], dexamethasone (OR = 2.45, 95%CI 1.14–5.42; P = 0.022), pre-treatment levels of serum calcium (OR = 0.27, 95%CI 0.13–0.54; P < 0.001), ALP/100 (OR = 1.04, 95%CI 1.01–1.07; P = 0.003), and haemoglobin (OR = 0.79, 95%CI 0.68–0.93; P = 0.004). ROC curve analysis revealed that the threshold for pre-treatment levels of serum calcium was ≤ 9.3 mg/dL, ALP was ≥ 457 U/L, and haemoglobin was ≤ 10.4 g/dL. In conclusion, concomitant use of vonoprazan or dexamethasone, and pre-treatment levels of serum calcium (low), ALP (high) and haemoglobin (low) were identified as significant predictors for the development of denosumab-induced hypocalcaemia.

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.

The Impact of Gastric Juice pH on the Intraluminal Therapy for Helicobacter pylori Infection

Background: Helicobacter pylori (H. pylori) can be topically eradicated in stomach lumen on endoscopic examination. The procedures of intraluminal therapy for H. pylori infection (ILTHPI) include the control of intragastric pH, mucolytic irrigation of the gastric mucosal surface, and a single-dose medicament containing antimicrobial agents. Aims: To detect gastric juice pH and evaluate its impact on the success rate of ILTHPI. Methods: We enrolled 324 patients with upper abdominal discomfort for endoscopic examinations. Among them, 13C-urea breath test was positive in 218 patients, where 100 underwent ILTHPI, and negative in 106. All patients had their gastric juice pH detected and set into three ranges, including normal acidity (pH < 4.0), low-level hypoacidity (pH 4.0–5.5), and high-level hypoacidity (pH ≥ 6.0). The impact of gastric juice pH on the success rate of ILTHPI was evaluated. Results: Distribution of pH level showed no significant difference between two groups of H. pylori-infected patients (p = 0.942). The eradication rate of ILTHPI is significantly lower in patients with gastric juice pH below 4 (p < 0.001). Conclusions: Detection of gastric juice pH in ILTHPI is extremely important. Rapid control of stomach pH at or above 4 for patients prior to ILTHPI is strongly recommended. (NCT03124420).

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.

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.

Phase III, randomised, double-blind, multicentre study to evaluate the efficacy and safety of vonoprazan compared with lansoprazole in Asian patients with erosive oesophagitis

OBJECTIVE

To establish the non-inferior efficacy of vonoprazan versus lansoprazole in the treatment of Asian patients with erosive oesophagitis (EO).

DESIGN

In this phase III, double-blind, multicentre study, patients with endoscopically confirmed EO were randomised 1:1 to receive vonoprazan 20 mg or lansoprazole 30 mg, once daily for up to 8 weeks. The primary endpoint was EO healing rate at 8 weeks. The secondary endpoints were EO healing rates at 2 and 4 weeks. Safety endpoints included treatment-emergent adverse events (TEAEs).

RESULTS

In the vonoprazan (n=238) and lansoprazole (n=230) arms, 8-week EO healing rates were 92.4% and 91.3%, respectively (difference 1.1% (95% CI -3.822% to 6.087%)). The respective 2-week EO healing rates were 75.0% and 67.8% (difference 7.2% (95% CI -1.054% to 15.371%)), and the respective 4-week EO healing rates were 85.3% and 83.5% (difference 1.8% (95% CI -4.763% to 8.395%)). In patients with baseline Los Angeles classification grade C/D, 2-week, 4-week and 8-week EO healing rates were higher with vonoprazan versus lansoprazole (2 weeks: 62.2% vs 51.5%, difference 10.6% (95% CI -5.708% to 27.002%); 4 weeks: 73.3% vs 67.2%, difference 6.2% (95% CI -8.884 to 21.223); and 8 weeks: 84.0% vs 80.6%, difference 3.4% (95% CI -9.187% to 15.993%)). Overall, EO healing rates appeared higher with vonoprazan versus lansoprazole. TEAE rates were 38.1% and 36.6% in the vonoprazan and lansoprazole group, respectively.

CONCLUSION

Our findings demonstrate the non-inferior efficacy of vonoprazan versus lansoprazole in terms of EO healing rate at 8 weeks in this population. Safety outcomes were similar in the two treatment arms.

TRIAL REGISTRATION NUMBER

NCT02388724.

Efficacy and Safety of Vonoprazan in Patients With Nonerosive Gastroesophageal Reflux Disease: A Randomized, Placebo-Controlled, Phase 3 Study

OBJECTIVES

To assess the efficacy and safety of vonoprazan on heartburn symptoms in patients with nonerosive reflux disease (NERD) (ClinicalTrials.gov: NCT02954848).

METHODS

This phase 3, double-blind, placebo-controlled study included Japanese patients aged 20 years and older with grade N/M NERD and recurrent heartburn. Patients received placebo (n = 245) or vonoprazan 10 mg (n = 238) for 4 weeks. The primary efficacy outcome was frequency of heartburn experienced by patients during the treatment period (proportion of days without heartburn). Other outcomes included cumulative improvement rates of heartburn, proportion of patients with complete heartburn resolution in the fourth week of treatment, and safety.

RESULTS

Compared with placebo, the proportion of days without heartburn was not significantly higher in the vonoprazan group in the full analysis (primary end point, 72.55% vs 61.50%, vonoprazan vs placebo, P = 0.0643) but was significantly higher in the per-protocol-set sensitivity analysis (P = 0.0341). Early onset of response and significantly greater cumulative improvement rates of heartburn were observed in the vonoprazan group (P = 0.0003). In a post hoc analysis, a greater proportion of patients with complete heartburn resolution in the fourth week of treatment were reported in the vonoprazan group (P = 0.0023). Incidence of treatment-emergent adverse events was similar between treatment groups (23.5% vs 23.3%); most treatment-emergent adverse events were mild in severity.

DISCUSSION

Although vonoprazan 10 mg was not superior to placebo with respect to proportion of days without heartburn in Japanese patients with NERD, vonoprazan had a significantly higher cumulative rate of heartburn resolution and was well tolerated.

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.

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 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.

Evaluation of gastric acid suppression with vonoprazan using calcium carbonate breath test

Vonoprazan, a potassium-competitive acid blocker, is a new class of acid-suppressing agent. The acid-inhibitory effect of vonoprazan has been well-documented. However, there is no report on the extent to which the amount of gastric acid secretion is suppressed, not pH measurement, by the use of vonoprazan. The aim of this study was to evaluate this suppression effect. This was a single-arm, interventional pilot study involving 7 healthy Japanese men. The subjects were administered 20 mg vonoprazan for 6 days. The amount of gastric acid secretion was determined using the calcium carbonate breath test. The acid outputs were defined as the maximum Δ¹³C‰ (Δ¹³C max) and area under the curve (AUC) during the 30 min sampling period. The Δ¹³C max and AUC values significantly decreased on the administration of 20 mg vonoprazan. The AUC dropped by approximately 78% on day 1 and by 84% on day 6 and subsequently returned to the control level after cessation of vonoprazan therapy (reduction by 68% on day 7 and by 42% on day 8). In conclusion, the amount of gastric acid secretion rapidly decreased by the administration of vonoprazan; this inhibitory effect was found to be potent and long-lasting. (UMIN ID: UMIN000025469).

[Pharmacological characteristics and clinical efficacies of a novel potassium-competitive acid blocker, vonoprazan fumarate]

Proton pump inhibitors (PPIs) inhibit H⁺, K⁺-ATPase, an enzyme which is the final step of gastric acid secretion and is selectively located in the gastric parietal cells. PPIs block the enzyme in a covalent and irreversible binding manner, thus providing better efficacy than previous pharmacological agents such as antacids and histamine H₂ receptor antagonists. Although PPIs have been the first-line therapeutic option for acid related diseases (ARDs), there are several limitations to their efficacy, i.e. short half-life in blood, insufficient acid suppression especially at night, necessity of repeated dosages for full action, and large variation in efficacy among patients due to CYP2C19 polymorphism. To overcome these shortcomings, we performed a high-throughput random screening using in-house chemical libraries and further lead optimization to look for the most relevant clinical candidate compounds. As the results of these researches, we discovered vonoprazan fumarate, a novel gastric acid antisecretory agent which inhibits H⁺, K⁺-ATPase in a reversible and K⁺-competitive manner. Vonoprazan exerted a more potent and longer lasting inhibitory effect than lansoprazole on gastric acid secretion in preclinical studies, presumably by its high accumulation profile in the gastric parietal cells. It also exhibited a rapid onset of action and prolonged inhibition of intragastric acidity in humans and showed remarkable effects on multiple ARDs including erosive esophagitis and Helicobacter pylori eradication. Vonoprazan fumarate was approved in 2014 for clinical use in Japan. Vonoprazan is a new therapeutic option which can potentially improve outcomes compared with conventional PPI-based treatments for ARDs.

Efficacy of Vonoprazan for Gastroesophageal Reflux Symptoms in Patients with Proton Pump Inhibitor-resistant Non-erosive Reflux Disease

Objective Clinically, patients with proton pomp inhibitor (PPI)-resistant gastroesophageal reflux disease (GERD) are very challenging to treat. The aim of this study was to determine the rates of symptom relief and adverse events among PPI-resistant GERD patients that changed their therapy from a PPI to vonoprazan. Methods Patients with severe gastroesophageal reflux symptoms (total GERD-Q score ≥8) without endoscopic findings of mucosal breaks who changed their medication from a PPI to vonoprazan during a 12-week period from 2015 to 2016 at 2 hospitals were selected. The primary outcome was the self-reported relief of gastroesophageal reflux symptoms. The odds ratio (OR) for the improvement of symptoms was calculated based on an exact binomial distribution using a matched-pair analysis. The secondary outcome was the GERD-Q score and adverse events. Results Twenty-six patients (6 men) with a mean age of 67.5 years were analyzed. After the therapy was changed from a PPI to vonoprazan, 18 patients (69.2%) reported an improvement, 6 (23.1%) reported no change, and 2 (7.7%) reported an exacerbation of symptoms. A change in therapy was significantly associated with improved self-reported symptoms (OR 9.0, p<0.001). The mean total GERD-Q score during vonoprazan treatment was significantly lower than that during PPI therapy (11.96 vs. 8.92). There were no significant differences in the incidence of adverse events between the therapies. Conclusion Changing the medication from a PPI to vonoprazan was significantly associated with an improvement in gastroesophageal reflux symptoms. Vonoprazan is one of the most promising treatment options for patients with PPI-resistant GERD.

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.