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

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

BACKGROUND AND AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSION

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

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

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

BACKGROUND AND OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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

Background

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

Materials and methods

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

Results

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

Conclusion

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

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Potential Benefits of Vonoprazan as Helicobacter pylori Infection Therapy

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

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

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

The pharmacotherapeutic management of gastroesophageal reflux disease (GERD)

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

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

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

Upper gastrointestinal bleeding in Japanese patients with ischemic heart disease receiving vonoprazan or a proton pump inhibitor with multiple antithrombotic agents: A nationwide database study

BACKGROUND

Vonoprazan has been launched as an alternative to proton-pump inhibitors (PPIs). This was the first study to compare the occurrence of upper gastrointestinal bleeding (UGIB) with vonoprazan treatment to that with PPI treatment in patients with ischemic heart disease (IHD) taking ≥2 antithrombotic agents, including those receiving dual antiplatelet therapy (DAPT).

METHODS

Using Japanese Diagnosis Procedure Combination data from 2016 to 2017, we identified 16,415 patients with IHD who were prescribed ≥2 antithrombotic agents, including new antiplatelet medication with concurrent vonoprazan (n = 2226 or PPIs n = 14,189). UGIB occurrence was analyzed using an inverse probability-weighted Cox proportional hazards model. Non-inferiority of vonoprazan to PPI treatment for UGIB occurrence was assessed.

RESULTS

Six-month incidence of UGIB in patients treated with vonoprazan and PPIs was 3.14% 70/2226 and 4.17% (591/14,189), respectively. The adjusted hazard ratio (aHR) of 0.84 was significantly below the non-inferiority margin (HR 2.06) (p < 0.0001), and thus demonstrated that vonoprazan treatment was non-inferior to PPIs in terms of occurrence of UGIB events. The difference between the 2 treatments was also not statistically significant [aHR 0.84; 95% confidence interval (CI): 0.65-1.07; p = 0.154). In a subgroup analysis, UGIB occurrence with vonoprazan and other PPI treatment in patients receiving DAPT was 2.82% (22/779) and 3.96% (209/5276) respectively; a non-significant difference (aHR 0.74; 95% CI: 0.48-1.16; p = 0.189) that demonstrated non-inferiority (p < 0.0001).

CONCLUSIONS

Vonoprazan was non-inferior to PPIs in terms of UGIB occurrence over 6 months in patients with IHD receiving ≥2 antithrombotic agents, including new antiplatelet medication.

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSION

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

TRIAL REGISTRATION NUMBER

UMIN000034140.

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

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

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

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

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

The Physiology of the Gastric Parietal Cell

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

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.

Comparison of efficacy of pharmacological therapies for gastric endoscopic submucosal dissection-induced ulcers: a systematic review and network meta-analysis

Objectives: This study aimed to compare the efficacy of various anti-ulcer medications in preventing delayed bleeding and promoting ulcer healing after ESD.Methods: Asystematic search was conducted for articles up to August2019. The treatments of iatrogenic ulcer were analyzed by Bayesian network meta-analysis.Results: The analysis included 28 studies. Six treatments were compared. For the prevention of delayed bleeding, potassium-competitive acid blocker (P-CAB) alone was superior to proton-pump inhibitor (PPI) alone [RR = 1.02, 95%CI (1.00, 1.05)]. Treatments based on P-CAB tended to be better than the non-P-CAB groups [RR = 1.05, 95%CI (1.03, 1.07)]. Concerning the ulcer healing rate at 4 weeks, the combined treatment of PPI and mucoprotective agent (MP) was superior to PPI alone [RR = 1.81, 95%CI (1.19, 2.76)] and P-CAB alone [RR = 2.75, 95%CI (1.02, 7.44)]. At 8 weeks, PPI+MP and P-CAB+MP tend to be superior to than the other four groups. The healing effect of MP-based therapies was better than that of non-MP groups at 4 weeks [RR = 1.63, 95%CI (1.32, 2.01)] and 8 weeks [RR = 1.06, 95%CI (1.02, 1.11)].Conclusion: P-CAB may prevent delayed bleeding, but not significantly. MP agents have the potential to heal post-ESD ulcers.

Randomised trial of acid inhibition by vonoprazan 10/20 mg once daily vs rabeprazole 10/20 mg twice daily in healthy Japanese volunteers (SAMURAI pH study)

BACKGROUND

Vonoprazan (V), a potassium-competitive acid blocker, has a more durable acid-inhibitory effect as compared with standard-dose proton pump inhibitors (PPIs) but has not been compared with 2-4 times higher daily PPI doses administered in two divided doses.

AIMS

To evaluate the acid-inhibitory effect of V 10/20 mg once-daily (OD; V10/V20) vs rabeprazole (R) 10/20 mg twice-daily (BID; R20/R40) in healthy Japanese volunteers.

METHODS

This multicentre, randomised, open-label, two-period, crossover study compared V10 or V20 vs R20, or V20 vs R40 using three cohorts of 10 healthy Japanese adults. Within each cohort, subjects were randomised to receive V or R for 7 days and, following a washout period ≥7 days, the other treatment for 7 days. On day 6 of each period, 24-hours multichannel gastric impedance-pH monitoring was performed. Percent times pH ≥ 3, ≥4 and ≥5 (pH 3, 4 and 5 holding time ratios [HTRs]) in 24 hours were evaluated as primary pharmacodynamic endpoints.

RESULTS

Acid-inhibitory effect (24-hours pH 3 HTR) of V20 was greater than those of R20 (91.0% vs 65.3%; P = .0049) and R40 (98.5% vs 85.9%; P = .0073). Similar results were obtained for 24-hours pH 4 and 5 HTRs. V20 also achieved greater nocturnal pH 4 (91.5% vs 73.2%; P = .0319) and 5 HTRs (78.8% vs 62.2%; P = .0325) as compared with R40. One subject (20%) developed diarrhoea while receiving R40 which was considered treatment-related.

CONCLUSIONS

Compared with 2-4 times the standard daily dose of R, V20 exerts a more potent and durable acid-inhibitory effect. Trial identifier: UMIN000022198 (www.umin.ac.jp/ctr/index.htm).

Clarithromycin Versus Metronidazole in First-Line Helicobacter Pylori Triple Eradication Therapy Based on Resistance to Antimicrobial Agents: Meta-Analysis

BACKGROUND

International treatment guidelines for Helicobacter pylori infection recommend a proton pump inhibitor (PPI)/amoxicillin/clarithromycin (CAM) regimen (PAC) or PPI/amoxicillin/metronidazole (MNZ) regimen (PAM) as first-line therapy based on culture and sensitivity testing. As incidence rates of antimicrobial agent-resistant strains are changing year by year, it is important to reevaluate the efficacy of eradication regimens. We performed a meta-analysis to evaluate the efficacy and safety of PAC and PAM based on different locations categorized by the reported incidence of CAM- and MNZ-resistant strains.

METHODS

Randomized control trials (RCTs) comparing eradication rates between PAC and PAM first-line treatment up to December 2018 were included. We divided RCTs into four groups based on resistance to CAM (< 15% or ≥ 15%) and MNZ (< 15% or ≥ 15%).

RESULTS

A total of 27 studies (4825 patients) were included. Overall eradication rates between PAC and PAM were similar (74.8% and 72.5%, relative risk (RR): 1.13, 95% confidence interval (CI): 0.91-1.39, P = 0.27) in the intention-to-treat analysis. In areas with low MNZ- and high CAM-resistance rates, PAM had a significantly higher eradication rate than PAC (92.5% vs. 70.8%, RR: 0.29, 95% CI: 0.13-0.68). In areas with high MNZ- and low CAM-resistance rates, the eradication rate with PAC was only 72.9%.

CONCLUSIONS

Overall eradication rates with PAC and PAM were equivalent worldwide. In low MNZ-resistance areas, PAM may be recommended as first-line therapy. However, the efficacy of PAC may be insufficient, irrespective of susceptibility to CAM.

Cytochrome P450-Based Drug-Drug Interactions of Vonoprazan In Vitro and In Vivo

Background

Vonoprazan fumarate is a potassium-competitive acid blocker that was developed as a novel acid-suppressing drug for multiple indications. As a potential alternative to proton-pump inhibitors, the determination of the drug-drug interactions is vital for further applications. Probe drug cocktails are a type of rapid, economical, and efficient approach for evaluating cytochrome P450 enzyme activities. Since vonoprazan is metabolized partly by cytochrome P450, cocktails were used to study CYP-based drug-drug interactions.

Methods

This study was conducted both in vitro and in vivo. In the in vitro study of rat liver microsomes, ultra-performance liquid chromatography coupled to tandem mass spectrometry was utilized to assess the reversible inhibition of cytochrome P450 by vonoprazan by determining the concentration of probe drugs (phenacetin, bupropion, tolbutamide, dextromethorphan, midazolam, chlorzoxazone). The differences in the levels of probe drugs between the rat groups with or without vonoprazan administration were also tested in the rats.

Results

In vitro analysis revealed that the IC₅₀ values of midazolam, tolbutamide, dextromethorphan, and bupropion in rat microsomes were 22.48, 18.34, 3.62, and 3.68 μM, respectively, while chlorzoxazone and phenacetin displayed no inhibition. In vivo analysis revealed that midazolam, bupropion, dextromethorphan, and tolbutamide showed significant (P < 0.05) differences in distinct pharmacokinetic parameters after vonoprazan administration, while those of chlorzoxazone and phenacetin were not significantly different.

Conclusion

The in vitro and in vivo results indicated that vonoprazan can inhibit CYP3A4, CYP2C9, CYP2D6, and CYP2B6, suggesting that the coadministration of vonoprazan with cytochrome P450 substrates should be performed cautiously in clinical settings.

Inhibitory Effect of Vonoprazan on the Metabolism of [14C]Prasugrel in Human Liver Microsomes

BACKGROUND AND OBJECTIVES

A recent report indicated that the pharmacodynamic interaction between clopidogrel and vonoprazan leading to attenuation of the anti-platelet effect of clopidogrel was unlikely to be caused by the inhibition of cytochrome P450 (CYP) 2B6, CYP2C19, or CYP3A4/5 by vonoprazan, based on in vitro CYP inhibition data. The current report investigates another important antiplatelet inhibitor, prasugrel, that is also activated through metabolism by CYP2B6, CYP2C19 and CYP3A4/5, for its CYP-based DDI potential with vonoprazan. The report describes in vitro metabolic inhibition assessments using radiolabeled prasugrel and human liver microsomes (HLMs).

METHODS

Reversible and time-dependent inhibition studies of vonoprazan as well as esomeprazole on the formation of the active metabolite R-138727 of prasugrel were conducted using HLMs.

RESULTS

Vonoprazan up to 10 μM, a concentration over 100-fold higher than the clinical maximum plasma concentration (C_max) of 75.9 nM after 20 mg once daily for 7 days, did not significantly affect the formation of R-138727 from [¹⁴C]prasugrel via reversible or time-dependent inhibition.

CONCLUSIONS

The in vitro data show that the pharmacodynamic interaction reported in the literature between vonoprazan and prasugrel is unlikely to be caused by CYP inhibition by vonoprazan. The results were similar to those obtained from the study with clopidogrel.

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 of Vonoprazan for Helicobacter pylori Eradication

Helicobacter pylori can infect the gastric mucosa and cause chronic inflammation, resulting in various diseases, including gastric cancer. Eradication of H. pylori in all infected subjects is recommended; however, the number of H. pylori strains with antibiotic resistance has increased, and the eradication rate has decreased. Vonoprazan, a potassium-competitive acid blocker, produces a stronger acid-inhibitory effect than proton pump inhibitors (PPIs). The H. pylori eradication rate with vonoprazan was found to be higher than that with PPIs. The H. pylori eradication rate with vonoprazan-based triple therapy (vonoprazan, amoxicillin, and clarithromycin) was approximately 90% and had an incidence of adverse events similar to that of PPIs. We review the current situation of H. pylori eradication in Japan, the first country in which vonoprazan was made available.

Risk of hemorrhage and stricture significantly increases in elderly patients with proton pump inhibitor (PPI)-resistant reflux esophagitis

BACKGROUND

To examine the clinical characteristics, including complications, of patients older than 75 years of age with proton pump inhibitor-resistant reflux esophagitis.

METHODS

Patients who were resistant to standard-dose proton pump inhibitors were enrolled in the present study. Eligible patients (n = 26) were divided into those who were older (n = 11) and younger (n = 15) than 75 years of age. Clinical characteristics including complications (hemorrhage and stricture), body mass index, the severity of reflux esophagitis, Helicobactor pylori infection, gastric mucosal atrophy, hiatal hernia, kyphosis, and the use of antithrombotic agents were examined. The efficacy of 20 mg vonoprazan for proton pump inhibitor-resistant reflux esophagitis was also investigated.

RESULTS

The severity of reflux esophagitis was significantly higher in the elderly group than in the non-elderly group. No other significant differences were observed between the groups. The proportion of patients with hemorrhage was significantly larger in the elderly group than in the non-elderly group. Similarly, the proportion of patients with stricture was significantly larger in the elderly group than in the non-elderly group. Nine out of 10 patients in the elderly group and all patients in the non-elderly group achieved healing after the 4-week administration of 20 mg vonoprazan. No significant differences were observed in healing rates between the groups.

CONCLUSION

Among patients with proton pump inhibitor-resistant reflux esophagitis, the rates of severe reflux esophagitis and complications (hemorrhage and/or stricture) were significantly higher in elderly patients than in non-elderly patients. Regardless of age, 20 mg vonoprazan was effective for proton pump inhibitor-resistant reflux esophagitis.

Changes of gastric ulcer bleeding in the metropolitan area of Japan

BACKGROUND

The two main causes of gastric ulcer bleeding are Helicobacter pylori (H. pylori) infection and ulcerogenic medicines, although the number of cases caused by each may vary with age. In Japan, the rate of H. pylori infection has fallen over the last decade and the number of prescriptions for non-steroidal anti-inflammatory drugs (NSAIDs) and antithrombotic drugs is increasing as the population ages. Methods of treatment for gastric ulcer bleeding have advanced with the advent of hemostatic forceps and potassium-competitive acid blocker (P-CAB). Thus, causes and treatments for gastric ulcer bleeding have changed over the last decade.

AIM

To examine the trends of gastric ulcer bleeding over 10 years in the metropolitan area of Japan.

METHODS

This is a single-center retrospective study. A total of 564 patients were enrolled from inpatients admitted to our hospital with gastric ulcer bleeding between 2006 and 2016. Age, medication history, H. pylori infection, method of treatment, rate of rebleeding, and the length of hospitalization were analyzed. Factors associated with gastric ulcer bleeding were evaluated using Fisher's exact test, Pearson's Chi-squared test or Student's t-test as appropriate. The Jonckheere-Terpstra test was used to evaluate trends. A per-protocol analysis was used to examine the rate of H. pylori infection.

RESULTS

There was a significant increase in the mean age over time (P < 0.01). The rate of H. pylori infection tended to decrease over the study period (P = 0.10), whereas the proportion of patients taking antithrombotic agents or NSAIDs tended to increase (P = 0.07). Over time, the use of NSAIDs and antithrombotic drugs increased with age. By contrast, the rate of H. pylori infection during the study period fell with age. H. pylori-induced ulcers accounted for the majority of cases in younger patients (< 70 years old); however, the rate decreased with age (P < 0.01). The method of treatment trend has changed significantly over time. The main method of endoscopic hemostasis has changed from clipping and injection to forceps coagulation (P < 0.01), and frequently prescribed medicines have changed from proton pump inhibitor to P-CAB (P < 0.01). The rate of rebleeding during the latter half of the study was significantly lower than that in the first half.

CONCLUSION

These trends, gastric ulcers caused by ulcerogenic drugs were increasing with age and H. pylori-induced ulcers were more common in younger patients, were observed.

Histamine2-Receptor Antagonists, Proton Pump Inhibitors, or Potassium-Competitive Acid Blockers Preventing Delayed Bleeding After Endoscopic Submucosal Dissection: A Meta-Analysis

Background: Endoscopic submucosal dissection (ESD) was commonly used for en bloc resection in gastric cancer and adenoma with the risk of delayed bleeding after ESD. We conducted a direct and indirect comparison meta-analysis to evaluate the best choice in preventing post-ESD bleeding among proton pump inhibitors (PPIs), histamine₂-receptor antagonists (H₂RAs), and the most widely used potassium-competitive acid blocker, vonoprazan.

Methods: The Pubmed, Cochrane Library, and Embase were searched for randomized trials. We pooled odds ratios (OR) for preventing post-ESD bleeding using meta-analysis.

Results: Sixteen randomized trials met the inclusion criteria including 2,062 patients. Direct comparisons showed slightly significant efficacy in PPIs rather than H₂RAs in preventing post-ESD bleeding [OR: 1.83; 95% confidence interval (CI): 1.10 to 3.05] and vonoprazan was better than PPIs (OR: 0.46; 95% CI: 0.25 to 0.86). The adjusted indirect comparison indicated vonoprazan was superior to H₂RAs (OR: 0.30, 95% CI: 0.12 to 0.74). In subgroup analysis, PPIs had similar efficacy as H₂RAs in 4 weeks, while PPIs were better than H₂RAs in 8 weeks’ treatment (OR: 1.91; 95% CI: 1.08 to 3.40). The superiority of vonoprazan than PPIs was more significant in combination therapy (OR: 0.18; 95% CI: 0.04 to 0.69). There was a significant difference in vonoprazan for 8 weeks of medication (OR: 0.44; 95% CI: 0.21 to 0.92).

Conclusions: The effects of vonoprazan is better than PPIs than H₂RAs in preventing bleeding after ESD. When vonoprazan combined with mucosal protective antiulcer drug in treatment or used in 8 weeks of medication, the efficacy may be even better.

Randomised clinical trial: safety, tolerability, pharmacokinetics, and pharmacodynamics of single and multiple oral doses of tegoprazan (CJ-12420), a novel potassium-competitive acid blocker, in healthy male subjects

BACKGROUND

Tegoprazan (CJ-12420) is a potassium-competitive acid blocker (P-CAB) with therapeutic potential for gastro-oesophageal reflux disease (GERD) by reversibly suppressing gastric H⁺ /K⁺ -ATPase.

AIMS

To investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of tegoprazan METHODS: A phase I, randomised, double-blind and placebo-controlled clinical trial was conducted in 56 healthy male subjects without Helicobacter pylori infection. In the single ascending dose study, 50, 100, 200 and 400 mg tegoprazan were administered to 32 subjects. In the multiple ascending dose study, 100 and 200 mg tegoprazan were administered every 24 hours to each of the eight subjects for 7 days. In the comparative pharmacodynamics study, 40 mg esomeprazole was administered to eight subjects every 24 hours for 7 days. The assessment included safety, tolerability, pharmacodynamics through monitoring of 24-hour gastric pH and pharmacokinetics of tegoprazan in plasma and urine.

RESULTS

Tegoprazan was generally well tolerated. Most adverse events reported in the study were mild in intensity and resolved without any sequelae. Exposure to tegoprazan increased in a dose-proportional manner. Multiple dosing with tegoprazan showed no accumulation in plasma on day 7. The pharmacodynamic analysis revealed that tegoprazan showed rapid, dose-dependent gastric acid suppression.

CONCLUSIONS

Tegoprazan was well tolerated and showed rapid and potent gastric acid suppression. This supports the further development of tegoprazan as a treatment for acid-related disorders.

Efficacy of long-term maintenance therapy with 10-mg vonoprazan for proton pump inhibitor-resistant reflux esophagitis

BACKGROUND

To investigate the efficacy of long-term (52 weeks) maintenance therapy by 10-mg vonoprazan administration for proton pump inhibitor-resistant reflux esophagitis continued from the preceding study.

METHODS

Sixteen patients with proton pump inhibitor-resistant reflux esophagitis (mean age 70.9 years, eight males) in whom endoscopic healing was achieved by 20-mg vonoprazan administration for 4 weeks and maintenance of remission was maintained by 10-mg vonoprazan administration for 8 weeks were enrolled. Endoscopy was performed at 52 weeks after the initiation of maintenance therapy with 10-mg vonoprazan to evaluate whether there was any recurrence of reflux esophagitis. Changes in the gastric mucosa were investigated at 52 weeks. Symptoms were assessed using the frequency scale for the symptoms of gastroesophageal reflux disease and the fast gastrin level at 8 and 52 weeks following the maintenance therapy.

RESULTS

Endoscopic remission was maintained at 52 weeks in 15 (93.8%) of the 16 patients with proton pump inhibitor-resistant reflux esophagitis. One patient relapsed with grade C of reflux esophagitis. There were no significant differences in the symptom score at 8 and 52 weeks, nor the gastrin level at 8 and 52 weeks. There was no change in the stomach on endoscopy at 52 weeks.

CONCLUSION

Long-term maintenance therapy by 10-mg vonoprazan administration is very effective for proton pump inhibitor-resistant reflux esophagitis patients in whom endoscopic healing was maintained by 8 weeks maintenance therapy with 10-mg vonoprazan administration.

Optimizing proton pump inhibitors in Helicobacter pylori treatment: Old and new tricks to improve effectiveness

The survival and replication cycle of Helicobacter pylori (H. pylori) is strictly dependant on intragastric pH, since H. pylori enters replicative phase at an almost neutral pH (6-7), while at acid pH (3-6) it turns into its coccoid form, which is resistant to antibiotics. On these bases, it is crucial to increase intragastric pH by proton pump inhibitors (PPIs) when an antibiotic-based eradicating therapy needs to be administered. Therefore, several tricks need to be used to optimize eradication rate of different regimens. The administration of the highest dose as possible of PPI, by doubling or increasing the number of pills/day, has shown to be able to improve therapeutic outcome and has often proposed in rescue therapies, even if specific trials have not been performed. A pre-treatment with PPI before starting antibiotics does not seem to be effective, therefore it is discouraged. However, the choice of PPI molecule could have a certain weight, since second-generation substances (esomeprazole, rabeprazole) are likely more effective than those of first generation (omeprazole, lansoprazole). A possible explanation is due to their metabolism, which has been proven to be less dependent on cytochrome P450 (CYP) 2C19 genetic variables. Finally, vonoprazan, a competitive inhibitor of H+/K+-ATPase present on luminal membrane of gastric parietal cells has shown the highest efficacy, due to both its highest acid inhibition power and rapid pharmacologic effect. However current data come only from Eastern Asia, therefore its strong power needs to be confirmed outside this geographic area in Western countries as well as related to the local different antibiotic resistance rates.

In search of the grail: A race for acid suppression

Proton pump inhibitors are the reference standards for the treatment of acid-related diseases. Acid suppression in gastroesophageal reflux disease is associated with a high rate of mucosal cicatrization, but symptom response differs among endoscopic phenotypes. Extraesophageal manifestations have a good clinical response in patients that present with abnormal acid exposure (diagnostic test) in the esophagus. Proton pump inhibitors have shown their effectiveness for reducing symptom intensity in nighttime reflux and sleep disorders, improving quality of life and work productivity. That can sometimes be achieved through dose modifications by splitting or increasing the dose, or through galenic formulation. Proton pump inhibitors are not exempt from controversial aspects related to associated adverse events. Technological development is directed at improving proton pump inhibitor performance through increasing the half-life, maximum concentration, and area under the curve of the plasma concentrations through galenic formulation, as well as creating safer and more tolerable drugs. The present review is focused on the mechanisms of action, pharmacokinetic properties, and technological advances for increasing the pharmacologic performance of a proton pump inhibitor.

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.

In Vitro Assessment of Potential for CYP-Inhibition-Based Drug-Drug Interaction Between Vonoprazan and Clopidogrel

BACKGROUND AND OBJECTIVES

It was recently proposed that CYP-mediated drug-drug interactions (DDIs) of vonoprazan with clopidogrel and prasugrel can attenuate the antiplatelet actions of the latter two drugs. Clopidogrel is metabolized to the pharmacologically active metabolite H4 and its isomers by multiple CYPs, including CYP2C19 and CYP3A4. Therefore, to investigate the possibility of CYP-based DDIs, in vitro metabolic inhibition studies using CYP probe substrates or radiolabeled clopidogrel and human liver microsomes (HLMs) were conducted in this work.

METHODS

Reversible inhibition studies focusing on the effects of vonoprazan on CYP marker activities and the formation of the [¹⁴C]clopidogrel metabolite H4 were conducted with and without pre-incubation using HLMs. Time-dependent inhibition (TDI) kinetics were also measured.

RESULTS

It was found that vonoprazan is not a significant direct inhibitor of any CYP isoforms (IC₅₀ ≥ 16 μM), but shows the potential for TDI of CYP2B6, CYP2C19, and CYP3A4/5. This TDI was weaker than the inhibition induced by the corresponding reference inhibitors ticlopidine, esomeprazole, and verapamil, based on the measured potencies (k_inact/K_I ratio and the R2 value). In a more direct in vitro experiment, vonoprazan levels of up to 10 µM (a 100-fold higher concentration than the plasma C_max of 75.9 nM after taking 20 mg once daily for 7 days) did not suppress the formation of the active metabolite H4 or other oxidative metabolites of [¹⁴C]clopidogrel in a reversible or time-dependent manner. Additionally, an assessment of clinical trials and post-marketing data suggested no evidence of a DDI between vonoprazan and clopidogrel.

CONCLUSIONS

The body of evidence shows that the pharmacodynamic DDI reported between vonoprazan and clopidogrel is unlikely to be caused by the inhibition of CYP2B6, CYP2C19, or CYP3A4/5 by vonoprazan.

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.

Development of Helicobacter pylori treatment: How do we manage antimicrobial resistance?

Helicobacter pylori (H. pylori) antimicrobial resistance is an urgent, global issue. In 2017, the World Health Organization designated clarithromycin-resistant H. pylori as a high priority bacterium for antibiotic research and development. In addition to clarithromycin, resistance to metronidazole and fluoroquinolones has also increased worldwide. Recent international guidelines for management of H. pylori infection recommend bismuth or non-bismuth quadruple therapy for 14 d as a first-line treatment for H. pylori in areas of high clarithromycin and/or metronidazole resistance. Although these treatment regimens provide acceptable H. pylori eradication rates, the regimens used should not contribute to future resistance of H. pylori to antimicrobials. Moreover, these regimens can promote resistance, due to prolonged therapy with multiple antibiotics. A new strategy that can eradicate H. pylori as well as reduce the antibiotics used is required to prevent future antimicrobial resistance in H. pylori. Dual-therapy with vonoprazan and amoxicillin could be a breakthrough for H. pylori eradication in an era of growing antimicrobial resistance. This regimen may provide a satisfactory eradication rate of H. pylori and also minimize antimicrobial resistance due to single antibiotic use and the strong inhibitory effect of vonoprazan on gastric acid secretion.

Randomised phase 3 trial: tegoprazan, a novel potassium-competitive acid blocker, vs. esomeprazole in patients with erosive oesophagitis

BACKGROUND

Tegoprazan is a novel potassium-competitive acid blocker that has a fast onset of action and can control gastric pH for a prolonged period, which could offer clinical benefit in acid-related disorders.

AIM

To confirm the non-inferiority of tegoprazan to esomeprazole in patients with erosive oesophagitis (EE).

METHODS

In this multicentre, randomised, double-blind, parallel-group comparison study, 302 Korean patients with endoscopically confirmed EE (Los Angeles Classification Grades A-D) were randomly allocated to either tegoprazan (50 or 100 mg) or esomeprazole (40 mg) treatment groups for 4 or 8 weeks. The primary endpoint was the cumulative proportion of patients with healed EE confirmed by endoscopy up to 8 weeks from treatment initiation. Symptoms, safety and tolerability were also assessed.

RESULTS

The cumulative healing rates at week 8 were 98.9% (91/92), 98.9% (90/91) and 98.9% (87/88) for tegoprazan 50 mg, tegoprazan 100 mg and esomeprazole 40 mg, respectively. Both doses of tegoprazan were non-inferior to esomeprazole 40 mg. The incidence of adverse events was comparable among the groups, and tegoprazan was well-tolerated.

CONCLUSION

Once daily administration of tegoprazan 50 or 100 mg showed non-inferior efficacy in healing EE and tolerability to that of esomeprazole 40 mg.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Effects of proton pump inhibitors, esomeprazole and vonoprazan, on the disposition of proguanil, a CYP2C19 substrate, in healthy volunteers

AIMS

Vonoprazan, a new class of potassium-competitive proton pump inhibitors has been found to attenuate the antiplatelet function of clopidogrel in a recent clinical study, despite weak in vitro activity against CYP2C19. To elucidate the mechanism of this interaction, the present study investigated the effects of esomeprazole and vonoprazan on the pharmacokinetics of proguanil, a CYP2C19 substrate.

METHODS

Seven healthy male volunteers (CYP2C19 extensive metabolizers) received a single oral administration of 100 mg proguanil/250 mg atovaquone (control phase), oral esomeprazole (20 mg) for 5 days followed by proguanil/atovaquone (esomeprazole phase) and oral vonoprazan (20 mg) for 5 days followed by proguanil/atovaquone (vonoprazan phase). Concentrations of proguanil and its metabolite, cycloguanil, in plasma and urine in each phase were determined using liquid chromatography-tandem mass spectrometry.

RESULTS

Coadministration with proton pump inhibitors resulted in increase and decrease in the area under the plasma concentration-time curve (AUC) of proguanil and cycloguanil, respectively, significantly reducing their AUC ratio (cycloguanil/proguanil) to 0.317-fold (95% confidence interval [CI] 0.256-0.379) and 0.507-fold (95% CI 0.409-0.605) in esomeprazole phase and vonoprazan phase, respectively. Esomeprazole and vonoprazan also significantly reduced the apparent formation clearance (cumulative amount of cycloguanil in urine divided by AUC of proguanil) to 0.324-fold (95% CI 0.212-0.436) and 0.433-fold (95% CI 0.355-0.511), respectively, without significant changes in renal clearance of proguanil and cycloguanil.

CONCLUSIONS

Although further studies are needed, both esomeprazole and vonoprazan potentially inhibit CYP2C19 at clinical doses, suggesting caution in the coadministration of these drugs with CYP2C19 substrates.