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

Vonoprazan causes symptomatic improvement in non-erosive gastroesophageal reflux disease: A systematic review and meta-analysis

OBJECTIVE

To evaluate the efficacy and safety of vonoprazan therapy as compared to conventional proton pump inhibitors (PPIs) or no vonoprazan for non-erosive esophagitis.

METHODS

A thorough search was conducted across databases. The primary outcome was to determine the mean variance in the gastroesophageal reflux disease (GERD) score after vonoprazan treatment. Secondary outcomes comprised alterations in the scores for epigastric pain and post-prandial distress, the proportion of patients displaying improvement, and the occurrence of adverse events. Pooled mean differences and relative risks were determined utilizing random effects models.

RESULTS

A total of 1,944 articles were screened and nine of them were included. As compared to PPI or no vonoprazan therapy, vonoprazan treatment led to a significant reduction in the GERD score [mean difference: -3.88 (95 % CI: -5.48, -2.28), p < 0.01, i2=95 %]. As compared to PPI or no vonoprazan therapy, vonoprazan treatment led to a significant reduction in the epigastric pain score [mean difference: -3.02 (95 % CI: -5.41, -0.63), p = 0.01, i2=75 %] and post-prandial distress score [mean difference: -2.82 (95 % CI: -3.51, -2.12), p < 0.01, i2=0 %] (all moderate GRADE evidence). Vonoprazan therapy was found to be safe.

CONCLUSION

Treatment with vonoprazan could significantly improve symptoms in patients with non-erosive esophagitis or non-erosive GERD.

Potassium-competitive acid blockers and acid-related disorders

PURPOSE OF REVIEW

Potassium-competitive acid blockers (PCABs) represent a new class of compounds for the treatment of acid-related disorders. Recent FDA approval of the PCAB vonoprazan for erosive esophagitis has started an important new approach to acid-related disorders.

RECENT FINDINGS

Compared to conventional proton pump inhibitors (PPIs), PCABs provide more rapid, potent, and sustained suppression of gastric acid with faster and more durable symptom relief. Studies have demonstrated the efficacy of PCABs for erosive esophagitis, nonerosive reflux disease, and peptic ulcer disease including H. pylori. However, the PCAB vonoprazan was only approved in the US as part of combination therapy for eradication of H. pylori. Clinical trials have now demonstrated noninferiority of vonoprazan to lansoprazole for treatment of erosive esophagitis, particularly noting superiority of vonoprazan in patients with severe esophagitis resulting in FDA approval of vonoprazan for treatment of erosive esophagitis. Emerging data suggests a possible utility of vonoprazan for PPI-resistant gastroesophageal reflux disease (GERD) and on-demand therapy for nonerosive reflux disease. Vonoprazan is generally well tolerated but long-term safety data is not well established.

SUMMARY

The PCAB vonoprazan is a newly FDA approved treatment option for erosive esophagitis. Its possible role in PPI-resistant GERD and nonerosive reflux disease warrants further investigation.

An update of pharmacology, efficacy, and safety of vonoprazan in acid-related disorders

INTRODUCTION

Patients with acid-related disorders (ARDs) of the upper digestive tract remain highly prevalent and need to be continuously investigated to improve their management.

AREAS COVERED

This review provides a summary of the most recent advancements in the treatment of ARDs with particular focus on the new drugs available to overcome the unmet needs of traditional therapies.

EXPERT OPINION

Proton pump inhibitors remain the best therapy in treating ARDs, but a consistent proportion of these patients continues to present mucosal lesions or to experience symptoms despite treatment. These cases pertain mainly to the most severe forms of erosive esophagitis or to non-erosive reflux disease. Also, the increasing rate of patients with H. pylori infection not responding to eradication therapy represents a difficult clinical condition. The recent advent of a new class of antisecretory drugs, such as the potassium competitive acid blockers and, among them the most studied vonoprazan, which are characterized by a better pharmacological profile than PPIs (rapid onset of action, longer lasting acid suppression, control of nocturnal acidity), has the potential to overcome the above-mentioned unmet needs. More research should be done to assess their efficacy in Western populations and their safety in patients treated in the long term.

Saliva secretion is reduced in mild reflux esophagitis patients

BACKGROUND

Salivary secretion in patients with mild reflux esophagitis has not been examined. In this study, saliva secretion and salivary epidermal growth factor (EGF) in patients with mild reflux esophagitis were investigated.

METHODS

Thirty-eight mild reflux esophagitis patients and 38 control subjects were recruited for this case-control study. Saliva secretion testing was performed. Saliva secretion was assessed as follows: each patient chewed sugar-free gum for 3 min prior to endoscopy, and the volume and pH of saliva before and after acid loading as an index of the acid-buffering capacity were measured. The salivary EGF concentration was assessed by ELISA.

RESULTS

The volume of saliva secreted was significantly (p = 0.0412) lower in the mild reflux esophagitis group than in the control group, with medians (25th-75th percentile) of 4.2 mL/3 min [2.6-6.2] and 6.0 [3.9-8.0], respectively. No significant differences were observed in salivary pH (the mild reflux esophagitis group: 7.1 [6.9-7.2], the control group 7.2 [7.1-7.3]). Salivary pH after acid loading was significantly (p = 0.0009) lower in the mild reflux esophagitis group (5.9 [5.5-6.3]) than in the control group (6.3 [6.2-6.5]). No significant differences were noted in salivary EGF concentrations (the mild reflux esophagitis group: 1739.0 pg/mL [1142.3-3329.0], the control group: 1678.0 [1091.8-2122.5].

CONCLUSION

The secretion volume and acid-buffering capacity of stimulated saliva were reduced in patients with mild reflux esophagitis.

A study for every second day administration of vonoprazan for maintenance treatment of erosive GERD (ESD von GERD): a multicenter randomized cross-over study

BACKGROUND

Vonoprazan is a potassium competitive acid blocker used to treat erosive gastroesophageal reflux disease (GERD) with stronger, more stable acid-suppressing effects than proton pump inhibitors (PPIs). This study clarified the usefulness and superiority of vonoprazan administered every second day over PPIs in the maintenance therapy of erosive GERD.

METHODS

This is a prospective, multicenter, open-label, two-period randomized cross-over study. Patients were randomized to either the vonoprazan-lansoprazole (VP-LZ) group, who were given vonoprazan 10 mg for the first 4 weeks and then lansoprazole 15 mg for the next 4 weeks both administered once every second day, or the lansoprazole-vonoprazan (LZ-VP) group, who were treated in reverse. GERD symptoms were compared using symptom diaries, the frequency scale for symptoms of GERD (FSSG), and the gastrointestinal symptom rating scale (GSRS).

RESULTS

We enrolled 122 patients between December 2017 and May 2019. Symptoms were well controlled in vonoprazan administration and lansoprazole administration were 93.6% and 82.1%, respectively, with a significant difference on McNemar's test (P = 0.003). During the second 4 weeks, 94.4% and 76.7% of patients in the VP-LZ and LZ-VP groups, respectively, were well controlled following for ≥ 6 consecutive days a week (P = 0.009). During the first 4 weeks, 96.7% and 80.0% of patients were well controlled with < 1 weekly in the VP-LZ and LZ-VP groups, respectively, during the first 4 weeks (P = 0.007). GERD symptoms, assessed via FSSG and GSRS, significantly decreased with vonoprazan administration once every second day.

CONCLUSIONS

Vonoprazan administered once every second day could be an effective alternative to PPIs in the maintenance treatment of erosive GERD (UMIN000030393).

Evidence-based clinical practice guidelines for gastroesophageal reflux disease 2021

In Japan, with the increasing prevalence of gastroesophageal reflux disease (GERD) and growing public interest, the Japanese Society of Gastroenterology issued Evidence-based Clinical Practice Guidelines for GERD (1st edition) in 2009 and a revised 2nd edition in 2015. A number of studies on GERD were subsequently conducted in Japan and abroad, and vonoprazan, a potassium-competitive acid blocker (P-CAB), became available for the first time in Japan in February 2015. The revised 3rd edition (Japanese edition), which incorporates new findings and information, was published in April 2021. These guidelines are summarized herein, particularly sections related to the treatment of GERD. The important clinical issues addressed in the present revision are (i) the introduction of treatment algorithms that classify GERD into reflux esophagitis and non-erosive reflux disease, (ii) the clarification of treatment algorithms based on to the severity of reflux esophagitis, and (iii) the positioning of vonoprazan in the treatment for GERD. The present guidelines propose vonoprazan as the initial/maintenance treatment for severe reflux esophagitis. They also recommend vonoprazan or PPI as an initial treatment for mild reflux esophagitis and recommended PPI and proposed vonoprazan as maintenance treatment. These updated guidelines offer the best clinical strategies for GERD patients in Japan and hope that they will be of global use for the diagnosis and treatment for GERD.

Vonoprazan for treatment of gastroesophageal reflux disease: Research advances

Gastroesophageal reflux disease is a common gastrointestinal disease that can be effectively treated by drugs alone. Proton pump inhibitors are the currently mainstay drugs for the treatment of gastroesophageal reflux disease, but are insufficiently effective. Vonoprazan, which is a new type of drug that inhibits gastric acid secretion, has been employed for the management of gastroesophageal reflux disease. In this article, we comprehensively review the current evidence regarding clinical efficacy and safety of vonoprazan for the treatment of gastroesophageal reflux disease to guide the clinical decision.

JianpiQinghua granule reduced PPI dosage in patients with nonerosive reflux disease: A multicenter, randomized, double-blind, double-dummy, noninferiority study

BACKGROUND

Proton pump inhibitors (PPIs) play an important role in the treatment of nonerosive reflux disease (NERD), but their long-term and excessive uses have been associated with safety concerns. Chinese herbal medicine (CHM) has become a popular alternative treatment for this condition.

METHODS

A total of 204 patients were randomly assigned to the combination group or PPI group (1:1 ratio). They were given JianpiQinghua (JQ) granules (34.8 g) plus omeprazole (10 mg) plus dummy omeprazole (10 mg) or dummy JQ granules (34.8 g) plus omeprazole (20 mg) daily for 4 weeks. The primary endpoints were the rate of sufficient relief and complete resolution of GERD Q at week 4. Metabonomics and the gut microbiota were also assessed.

RESULTS

Complete resolution was observed in 40.8% of patients in the combination group and 26.8% of patients in the PPI group after 4 weeks (FAS analysis, OR, 1.88; 95% CI, 1.03-3.44; p = 0.039). Sufficient relief was observed in 50% of patients in the combination group and 43.30% of patients in the PPI group after 4 weeks (FAS analysis, OR, 1.31; 95% CI, 0.74-2.30; p = 0.35). Three patients had liver dysfunction, one of whom had a mild case and 2 of whom had moderate-to-severe cases in the combination group. Patients in the combination group showed a significant increase in richness and diversity of their gut microbiota compared with those in the PPI group. Metabonomics showed that the combination therapy could correct the glutamate metabolism pathway.

CONCLUSION

Our findings demonstrate the superior efficacy of JQ granules combined with omeprazole (10 mg) vs. omeprazole (20 mg) in terms of symptom relief in patients with NERD.

TRIAL REGISTRATION

ClinicalTrials.gov number NCT02892357. Registered on 14 February 2019.

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.

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.