Prevention of relapse of healed reflux esophagitis is related to the duration of intragastric pH > 4

Vonoprazan: A Review in Erosive Esophagitis and Non-Erosive Gastro-Esophageal Reflux Disease

Vonoprazan (Voquezna®) is a potassium-competitive acid blocker (PCAB) with improved pharmacodynamic and pharmacokinetic properties compared with proton-pump inhibitors (PPIs) that allow for stronger control of gastric acid with once-daily oral administration and no requirement to be taken in relation to timing of meals for optimal efficacy. In the USA, vonoprazan has been approved as a first-in-class treatment for healing and maintenance of healing of erosive esophagitis, and for relief of heartburn in adult patients with erosive esophagitis and non-erosive gastro-esophageal reflux disease (GERD). In pivotal phase III trials, vonoprazan was non-inferior to the PPI lansoprazole in healing and superior to lansoprazole in maintenance of healing of erosive esophagitis, and was superior to placebo for treating heartburn in US patients with non-erosive GERD. Vonoprazan was generally well tolerated; the most common adverse events included abdominal pain, constipation, diarrhea, nausea, and dyspepsia. Vonoprazan is, therefore, a valuable addition to the therapies available for adults with erosive esophagitis and non-erosive GERD.

The Role of P-CABs in GERD

Potassium-competitive acid blockers (P-CABs) constitute a relatively new class of gastric acid-suppressing drugs. Among this class, vonoprazan is the first to have been approved in the United States. However, some P-CABs including vonoprazan, tegoprazan, and fexuprazan have been available in other countries since at least 2014. The first aim of this article is to review pharmacological differences between P-CABs that are currently approved or in development with proton pump inhibitors. The specific focus thereafter is on the likely role of P-CABs in the treatment of different manifestations of gastroesophageal reflux disease. Multiple clinical trials have compared P-CABs with proton pump inhibitors in erosive esophagitis. Additional trials have compared P-CABs with placebo in nonerosive reflux disease. Relevant results are reviewed, and inferences are drawn for their use in the United States. Finally, consideration is given to additional, potential uses of P-CABs in the broader spectrum of gastroesophageal reflux disease, and some suggestions are made for future research initiatives.

Potassium-competitive acid blockers: rethinking acid suppression for gastroesophageal reflux disease and Helicobacter pylori

Gastroesophageal reflux disease (GERD) and Helicobacter pylori (H. pylori) infection are different disease states that are united by the core role of acid suppression in their management. In GERD, proton pump inhibitors (PPIs) have long been standard therapy based on abundant positive clinical trial data supporting their efficacy and safety. In H. pylori, PPIs are also a critical element of therapy in combination with 1 or more antibiotics to achieve and maintain a pH that maximizes the efficacy of therapy. Despite the considerable clinical success and widespread use of PPIs, room remains for agents with differentiated pharmacokinetic and pharmacodynamic profiles. The potassium-competitive acid blockers (PCABs) are mechanistically distinct from PPIs but are acid-stable and do not require activation of the proton pump by coadministration of food. In pharmacodynamic studies, these agents have shown greater durations of acid suppression above the critical threshold of pH 4 (for GERD) and pH 6 (for H. pylori), which have been shown to optimize therapeutic efficacy in these settings. These results have translated in clinical studies to similar and, in some cases, improved outcomes relative to PPIs in these disease states. This review summarizes current knowledge on the physiology of acid secretion, pathophysiology and management of GERD and H. pylori, and key characteristics and clinical trial data for PPIs and PCABs.

Pilot, Randomized, Blinded, Placebo-Controlled Trial Investigating the Correlation Between Acid Control and Heartburn Relief with 14 Days of Esomeprazole Treatment

INTRODUCTION

Reflux symptoms are frequently associated with esophageal acid exposure. However, other potential causes unrelated to acid secretion are possible, and the relationship between acid control and symptomatic improvement remains unclear. This study investigated the correlation between individual intragastric pH control and heartburn relief among subjects with frequent heartburn who are likely to self-treat with over-the-counter (OTC) medications. We hypothesized that improved acid control would provide greater symptomatic improvement among individuals representative of an OTC population.

METHODS

This phase 4, single-center, randomized, double-blind, placebo-controlled study was conducted in subjects without diagnosed gastroesophageal reflux disease or other gastrointestinal conditions who were experiencing frequent heartburn (≥ 3 episodes/week; ≥ 2 nighttime episodes/week over past 30 days) that was responsive to treatment. Subjects entered a 7-day run-in phase, received placebo BID (before breakfast and dinner), and completed symptom diaries. During the treatment phase, subjects received esomeprazole 20 mg BID, esomeprazole 20 mg then placebo, or placebo BID. Subjects underwent 24-h intragastric pH monitoring at baseline and day 14 and completed daily symptom diaries.

RESULTS

In the per-protocol population (n = 39), mean (SD) change from baseline in percentage of time with intragastric pH > 4 was 58.7% (± 26.4%) versus 41.0% (± 30.4%) for those who did and did not achieve 24-h heartburn relief. Significant correlations were observed between change in percentage of time with intragastric pH > 4 and 24-h heartburn relief (OR 1.028; 95% CI 1.001, 1.055; P = 0.0442) and complete resolution (OR 1.034; 95% CI 1.003, 1.065; P = 0.0301).

CONCLUSIONS

Individuals with greater improvements in duration of intragastric acid suppression had an increased likelihood of achieving heartburn relief and resolution. These results indicate that individuals not adequately controlling their intragastric pH may require an escalation in dose of their acid-suppressive therapy, assessment with 24-h pH monitoring, or a change in treatment regimen to address non-reflux-related etiologies of their heartburn.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02708355.

FUNDING

Pfizer Consumer Healthcare, Madison, NJ, USA. Plain language summary available for this article.

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

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

Gastroesophageal Acid Reflux Control 5 Years After Antireflux Surgery, Compared With Long-term Esomeprazole Therapy

BACKGROUND & AIMS

We compared the ability of laparoscopic antireflux surgery (LARS) and esomeprazole to control esophageal acid exposure, over a 5-year period, in patients with chronic gastroesophageal reflux disease (GERD). We also studied whether intraesophageal and intragastric pH parameters off and on therapy were associated with long-term outcomes.

METHODS

We analyzed data from a prospective, randomized, open-label trial comparing the efficacy and safety of LARS vs esomeprazole (20 or 40 mg/d) over 5 years in patients with chronic GERD. Ambulatory intraesophageal and intragastric 24-hour pH monitoring data were compared between groups before LARS or the start of esomeprazole treatment, and 6 months and 5 years afterward. A secondary aim was to evaluate the association between baseline and 6-month pH parameters and esomeprazole dose escalation, reappearance of GERD symptoms, and treatment failure over 5 years in patients receiving LARS or esomeprazole.

RESULTS

In the LARS group (n = 116), the median 24-hour esophageal acid exposure was 8.6% at baseline and 0.7% after 6 months and 5 years (P < .001 vs baseline). In the esomeprazole group (n = 151), the median 24-hour esophageal acid exposure was 8.8% at baseline, 2.1% after 6 months, and 1.9% after 5 years (P < .001, therapy vs baseline, and LARS vs esomeprazole). Gastric acidity was stable in both groups. Patients who required a dose increase to 40 mg/d had more severe supine reflux at baseline, and decreased esophageal acid exposure (P < .02) and gastric acidity after dose escalation. Esophageal and intragastric pH parameters, off and on therapy, did not predict long-term symptom breakthrough.

CONCLUSIONS

In a prospective study of patients with chronic GERD, esophageal acid reflux was reduced greatly by LARS or esomeprazole therapy. However, patients receiving LARS had significantly greater reductions in 24-hour esophageal acid exposure after 6 months and 5 years. Esophageal and gastric pH, off and on therapy, did not predict long-term outcomes of patients. Abnormal supine acid exposure predicted esomeprazole dose escalation. ClinicalTrials.Gov identifier: NCT00251927 (available: http://clinicaltrials.gov/ct2/show/NCT00251927).

Randomized, multicenter study: on-demand versus continuous maintenance treatment with esomeprazole in patients with non-erosive gastroesophageal reflux disease

Background

Most patients with gastroesophageal reflux disease experience symptomatic relapse after stopping acid-suppressive medication. The aim of this study was to compare willingness to continue treatment with esomeprazole on-demand versus continuous maintenance therapy for symptom control in patients with non-erosive reflux disease (NERD) after 6 months.

Methods

This multicenter, open-label, randomized, parallel-group study enrolled adults with NERD who were heartburn-free after 4 weeks’ treatment with esomeprazole 20 mg daily. Patients received esomeprazole 20 mg daily continuously or on-demand for 6 months. The primary variable was discontinuation due to unsatisfactory treatment. On-demand treatment was considered non-inferior if the upper limit of the one-sided 95 % confidence interval (CI) for the difference between treatments was <10 %.

Results

Of 877 patients enrolled, 598 were randomized to maintenance treatment (continuous: n = 297; on-demand: n = 301). Discontinuation due to unsatisfactory treatment was 6.3 % for on-demand and 9.8 % for continuous treatment (difference −3.5 % [90 % CI: −7.1 %, 0.2 %]). In total, 82.1 and 86.2 % of patients taking on-demand and continuous therapy, respectively, were satisfied with the treatment of heartburn and regurgitation symptoms, a secondary variable (P = NS). Mean study drug consumption was 0.41 and 0.91 tablets/day, respectively. Overall, 5 % of the on-demand group developed reflux esophagitis versus none in the continuous group (P < 0.0001). The Gastrointestinal Symptom Rating Scale Reflux dimension was also improved for continuous versus on-demand treatment. Esomeprazole was well tolerated.

Conclusions

In terms of willingness to continue treatment, on-demand treatment with esomeprazole 20 mg was non-inferior to continuous maintenance treatment and reduced medication usage in patients with NERD who had achieved symptom control with initial esomeprazole treatment.

Trial registration

ClinicalTrials.gov identifier (NCT number): NCT02670642; Date of registration: December 2015.

Lower serum level of adiponectin is associated with increased risk of endoscopic erosive gastritis

BACKGROUND

Obesity is recently known as a risk factor for endoscopic gastritis. Adiponectin is an anti-inflammatory cytokine secreted from fat tissue, and its serum concentrations are reduced in obesity. The relation between adiponectin and gastritis remains unclear.

AIMS

The aim of this study was to determine whether lower serum adiponectin level is associated with the risk of endoscopic gastritis.

METHODS

We analyzed medical records of participants of a routine health check-up examination. Association among endoscopic findings, serum adiponectin level, and other clinical factors including age, sex, alcohol habit, smoking habit, body mass index (BMI), blood pressure, cholesterol, triglyceride, glucose, and insulin were investigated. Endoscopic erosive gastritis was defined as a flat or minimally depressed white spot surrounded by a reddish area or small elevation with central umbilications mimicking octopus' suckers.

RESULTS

A total of 2,400 participants were enrolled. BMI was significantly higher in gastritis-positive participants than in gastritis-negative participants. Serum adiponectin levels were significantly lower in gastritis-positive participants than in gastritis-negative participants. Multivariate logistic regression analysis revealed that lower serum adiponectin level (OR 0.96; 95% CI 0.93-0.99), smoking (OR 0.50; 95% CI 0.30-0.80), higher blood pressure (OR 1.02; 95% CI 1.01-1.03), and duodenitis (OR 1.8; 95% CI 1.00-3.09) were significantly associated with endoscopic erosive gastritis.

CONCLUSIONS

Lower serum level of adiponectin may increase the risk of endoscopic erosive gastritis, independently of BMI. Our findings facilitate further study to clarify the role of hypoadiponectinemia in erosive gastritis.