A randomized, comparative study of three doses of AZD0865 and esomeprazole for healing of reflux esophagitis

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

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

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

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

Comparison of hepatotoxicity of tegoprazan, a novel potassium-competitive acid blocker, with proton pump inhibitors using real-world data: A nationwide cohort study

Background

Proton pump inhibitors (PPIs) are acid suppressants that are frequently prescribed in many countries to reduce heartburn. A potassium-competitive acid blocker (P-CAB; tegoprazan) was launched relatively recently that also inhibits gastric acid secretion. This study aimed to compare the hepatotoxicity of the six existing PPIs with P-CAB.

Methods

This retrospective cohort study was conducted between January 2019 and December 2020 and included data from the total population of 50 million inhabitants in Korea. Propensity score (PS) matching was performed using 10 variables, and the differences in hepatotoxicity between P-CAB and the six PPIs were compared in a similar distribution. The primary endpoint was hepatotoxicity which included toxic liver disease, hepatitis, hepatic failure, liver transplantation, and other liver diseases.

Results

The risk ratios (RR) of tegoprazan vs. the six PPIs (dexlansoprazole, esomeprazole, lansoprazole, omeprazole, pantoprazole, and rabeprazole) were all significant [RR: 0.70 (95% CI: 0.69-0.72), 0.81 (95% CI: 0.79-0.83), 0.61 (95% CI: 0.59-0.63), 1.17 (95% CI: 1.13-1.20), 0.61 (95% CI: 0.59-0.62), and 0.73 (95% CI: 0.71-0.75), respectively]. The risk ratio of tegoprazan vs. the six existing PPIs was 0.73 (95% CI: 0.72-0.75). The hazard ratios (HRs) of hepatotoxicity of the six PPIs to tegoprazan showed significantly higher values apart from omeprazole (HR: dexlansoprazole, 1.13; esomeprazole, 1.04; lansoprazole, 1.25; omeprazole, 0.77; pantoprazole, 1.26; rabeprazole, 1.15, respectively, and the six existing PPIs, 1.10).

Conclusion

Using a large-scale data cohort analysis consisting of 50 million Koreans, tegoprazan did not induce higher hepatotoxicity compared with the six conventional PPIs.

A comparison of efficacy and safety of potassium-competitive acid blocker and proton pump inhibitor in gastric acid-related diseases: A systematic review and meta-analysis

BACKGROUND AND AIM

Potassium-competitive acid blocker (PCAB) is a recent alternative to proton pump inhibitor (PPI) for potent acid suppression. The current systematic review and meta-analysis aimed to compare the efficacy and safety of PCAB versus PPI in treating gastric acid-related diseases.

METHODS

We searched up to June 5, 2022, for randomized controlled trials of gastric acid-related diseases that included erosive esophagitis, symptomatic gastroesophageal reflux disease (GERD), peptic ulcers, and Helicobacter pylori infection. The pooled risk ratio (RR) was evaluated for the efficacy outcome and treatment-emergent adverse events (TEAEs) as the safety outcome. Sensitivity analyses were performed to test the robustness of the study findings.

RESULTS

Of the 710 screened studies, 19 studies including 7023 participants were analyzed. The RRs for the healing of erosive esophagitis with Vonoprazan versus PPI were 1.09 (95% confidence interval [CI] 1.03-1.14), 1.03 (95% CI 1.00-1.07), and 1.02 (95% CI 1.00-1.05) in Weeks 2, 4, and 8, respectively. There were no differences in the improvement of GERD symptoms and healing of gastric and duodenal ulcers between PCAB and PPI. The pooled eradication rates of H. pylori were significantly higher in Vonoprazan versus PPI first-line treatment (RR 1.13; 95% CI 1.04-1.22). The overall RR of TEAEs with Vonoprazan versus PPI was 1.08 (95% CI 0.89-1.31). Overall, the risk of bias was low to some concerns. Furthermore, sensitivity analyses confirmed the robustness of the study's conclusion.

CONCLUSION

Vonoprazan is superior to PPI in first-line H. pylori eradication and erosive esophagitis but non-inferior in other gastric acid-related diseases. Likewise, short-term safety is comparable in both treatment groups.

The role of vonoprazan in patients with erosive esophagitis

Acid suppression is the primary therapy for erosive esophagitis (EE). Although proton pump inhibitors (PPIs) are considered as the first-line medication for EE, 10-20% of patients with Los Angeles C and D grade EE do not gain complete mucosal healing and symptom control despite 8-week double-dose PPI treatment. Vonoprazan is a novel potassium-competitive acid blocker (P-CAB), which blocks the H⁺, K⁺-adenosine triphosphatase enzymes in a K⁺-competitive and reversible manner. Vonoprazan exhibits different pharmacological and pharmacokinetic profiles from conventional PPIs, and has a rapid, potent and sustained acid inhibitory effect. In this review, we summarized and discussed current evidence regarding the role of vonoprazan in terms of mucosal healing, maintaining remission and symptom relief for the management of EE, including the initial and maintenance treatment of EE, as well as for PPI-resistant EE patients. Safety concerns and cost-effectiveness analysis of vonoprazan were also mentioned in the article. As a potent and well-tolerated acid blocker, vonoprazan has the potential to become a novel option for the management of EE.

Potassium-competitive acid blockers and gastroesophageal reflux disease

Proton pump inhibitors (PPIs), the most commonly used antisecretory medi-cations in the management of reflux illness, virtually eliminate elective surgery for ulcer disease, and relegate anti-reflux surgery to patients with gastroesophageal reflux disease (GERD) who are inadequately managed by medical therapy. However, PPI medications still leave some therapeutic demands of GERD unmet. Furthermore, up to 40%-55% of daily PPI users have chronic symptoms, due to PPI refractoriness. Potassium-competitive acid blockers (P-CABs) transcend many of the problems and limits of PPIs, delivering quick, powerful, and extended acid suppression and allowing for treatment of numerous unmet needs. Recently, it has become clear that compromised mucosal integrity plays a role in the etiology of GERD. As a result, esophageal mucosal protection has emerged as a novel and potential treatment approach. An increasing body of research demonstrates that when P-CABs are used as primary drugs or add-on drugs (to regular treatment), they provide a considerable extra benefit, particularly in alleviating symptoms that do not respond to PPI therapy.

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.

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.

Revisiting Montreal: New Insights into Symptoms and Their Causes, and Implications for the Future of GERD

The Montreal definition of gastroesophageal reflux disease (GERD) provided a rationale for acid suppression medication without investigation, thus enhancing the management of the substantial symptom burden in these patients. Increased proton-pump inhibitor use has also highlighted their limitations, with one third of "typical" symptoms known to be refractory. Most refractory symptoms are ascribed to reflux hypersensitivity (RH) and functional heartburn (FH). RH may be caused by impaired esophageal mucosal barrier function and sensitization of peripheral esophageal receptors. Central sensitization may also contribute to the perception of non-pathologic reflux in RH, and the perception of physiological stimuli in FH. Importantly, mechanisms underlying GERD, RH, and FH are (in theory) not mutually exclusive, further complicating patient management. Methods used to distinguish GERD from RH and FH are impractical for use in epidemiological studies and pragmatic care and may have limited diagnostic accuracy. This is impeding accurate prevalence estimates and risk factor determination and the identification of new therapies. Direct assessment of mucosal barrier function by measuring impedance is a promising candidate for improved diagnosis. Ultimately though the concept of GERD as a composite, symptom-based entity needs re-evaluation, so that new understandings of upper GI symptoms can direct more precise management.

Pyrrole: An insight into recent pharmacological advances with structure activity relationship

Pyrrole is a heterocyclic ring template with multiple pharmacophores that provides a way for the generation of library of enormous lead molecules. Owing to its vast pharmacological profile, pyrrole and its analogues have drawn much attention of the researchers/chemists round the globe to be explored exhaustively for the benefit of mankind. This review focusses on recent advancements; pertaining to pyrrole scaffold, discussing various aspects of structure activity relationship and its bioactivities.

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

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

Advantages and Disadvantages of Long-term Proton Pump Inhibitor Use

Proton pump inhibitors (PPIs) potently inhibit gastric acid secretion and are widely used for treatment of acid-related diseases including gastroesophageal reflux disease and secondary prevention of aspirin/NSAID-induced ulcers. Although clinically important adverse effects of PPIs can occur, just as with other drugs, those are not frequently observed during or after administration. Thus, PPIs are regarded as relatively safe and considered to be clinically beneficial. Recently, PPIs have become frequently administered to patients with functional gastrointestinal diseases or primary prevention of drug-related gastroduodenal damage, even though their beneficial effects for those conditions have not been fully confirmed. PPIs tend to be given for conditions in which the necessity of the drug has not been clarified, thus otherwise rare adverse effects are presented as clinically relevant. Although several PPI-related adverse effects have been reported, their clinical relevance is not yet clear, since the evidence reported in those studies is not at a high enough level, as the majority are based on retrospective observational studies and the reported hazard ratios are low. It is important to administer PPIs only for patients who will gain a substantial clinical benefit and to continue to investigate their adverse effects with high quality prospective studies.

Maintenance for healed erosive esophagitis: Phase III comparison of vonoprazan with lansoprazole

AIM

To compare vonoprazan 10 and 20 mg vs lansoprazole 15 mg as maintenance therapy in healed erosive esophagitis (EE).

METHODS

A total of 607 patients aged ≥ 20 years, with endoscopically-confirmed healed EE following 8 wk of treatment with vonoprazan 20 mg once daily, were randomized 1:1:1 to receive lansoprazole 15 mg (n = 201), vonoprazan 10 mg (n = 202), or vonoprazan 20 mg (n = 204), once daily. The primary endpoint of the study was the rate of endoscopically-confirmed EE recurrence during a 24-wk maintenance period. The secondary endpoint was the EE recurrence rate at Week 12 during maintenance treatment. Additional efficacy endpoints included the incidence of heartburn and acid reflux, and the EE healing rate 4 wk after the initiation of maintenance treatment. Safety endpoints comprised adverse events (AEs), vital signs, electrocardiogram findings, clinical laboratory results, serum gastrin and pepsinogen I/II levels, and gastric mucosa histopathology results.

RESULTS

Rates of EE recurrence during the 24-wk maintenance period were 16.8%, 5.1%, and 2.0% with lansoprazole 15 mg, vonoprazan 10 mg, and vonoprazan 20 mg, respectively. Vonoprazan was shown to be non-inferior to lansoprazole 15 mg (P < 0.0001 for both doses). In a post-hoc analysis, EE recurrence at Week 24 was significantly reduced with vonoprazan at both the 10 mg and the 20 mg dose vs lansoprazole 15 mg (5.1% vs 16.8%, P = 0.0002, and 2.0% vs 16.8%, P < 0.0001, respectively); by contrast, the EE recurrence rate did not differ significantly between the two doses of vonoprazan (P = 0.1090). The safety profiles of vonoprazan 10 and 20 mg were similar to that of lansoprazole 15 mg in patients with healed EE. Treatment-related AEs were reported in 11.4%, 10.4%, and 10.3% of patients in the lansoprazole 15 mg, vonoprazan 10 mg, and vonoprazan 20 mg arms, respectively.

CONCLUSION

Our findings confirm the non-inferiority of vonoprazan 10 and 20 mg to lansoprazole 15 mg as maintenance therapy for patients with healed EE.

The Use of Proton Pump Inhibitors in Intensive Care Units

The bleeding from the upper gastrointestinal tract represent a significant medical but also socio-economic problem. A special group of patients et increased risk consists of critically ill patients in intensive care units. Particularly significant cause of bleeding in intensive care unit patients is bleeding resulting from the stress ulcers caused by damage of the mucosa of the stomach and duodenum.

The purpose of this review is to present current experience in prevention of upper gastrointestinal tract bleeding using proton pump inhibitors in intensive care units.

Combination of endoscopic hemostatic methods and proton pump inhibitors represents golden standard in most cases.

Despite some adverse effects treatment with proton pump blockers is essential when upper gastrointestinal tract bleeding appears in critically ill patients in intensive care units. Proton pump inhibitors are more effective in acid suppression, as well as in the prevention of recurrent bleeding after endoscopic hemostasis than histamine 2 receptor blockers. The efficacy of proton pump blockers is higher in the case of a continuous intravenous infusion than in the intermittent mode of administration of the drug. The need for highly elaborate strategy for the prophylaxis of bleeding from the upper parts of gastrointestinal tract in intensive care units is essential, because when it occurs in intensive care units, mortality is high, and therapeutic options become narrow.

Vonoprazan: A Novel and Potent Alternative in the Treatment of Acid-Related Diseases

Although proton pump inhibitors (PPIs) have been used widely, acid-related diseases are still associated with a huge burden on the health care system. Recently, the efficacy and safety of a new acid suppressant named vonoprazan in the treatment of acid-related diseases have been evaluated by a series of studies. As a novel potassium-competitive acid blocker, vonoprazan may provide reversible acid suppression by preventing K⁺ from binding to gastric H⁺/K⁺-ATPase. It has been clinically used for the short-term treatment of gastroesophageal reflux disease (GERD), peptic ulcer disease and Helicobacter pylori (H. pylori) infection in Japan. The healing rate of GERD and gastric ulcers by vonoprazan is more than 95 and 90%, respectively; also, it is effective in curing PPI-resistant GERD. It increases H. pylori eradication rate to more than 88% as part of both first-line and second-line therapy. It is also effective in the eradication of clarithromycin-resistant H. pylori strains. All of these short-term studies show vonoprazan is safe and well-tolerated. As a safe and effective acid inhibitor, vonoprazan might be a novel alternative in the treatment of acid-related diseases.

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.

Recent Advances in the Pharmacological Management of Gastroesophageal Reflux Disease

The management of proton pump inhibitor-refractory GERD (rGERD) is a challenge in clinical practice. Since up to one-third of patients with typical GERD symptoms (heartburn and/or acid regurgitation) are not satisfied with proton pump inhibitor (PPI) therapy, new drug development targeting different pathophysiologies of GERD is imperative. At present, no other drugs serve as a more potent acid suppression agent than PPIs. As an add-on therapy, histamine type-2 receptor antagonists, alginates, prokinetics and transient lower esophageal sphincter relaxation inhibitors have some impact on the subgroups of rGERD, but greater effectiveness and fewer adverse effects for widespread use are required. Visceral hypersensitivity also contributes to the perception of GERD symptoms, and neuromodulators including antidepressants play a role in this category. Esophageal pH-impedance monitoring helps to distinguish functional heartburn from true GERD, and psychologic medication and cognitive behavior therapy are further therapy options instead of PPIs.

Pharmacokinetic Drug-Drug Interactions Between Vonoprazan and Low-Dose Aspirin or Nonsteroidal Anti-inflammatory Drugs: A Phase 2, Open-Label, Study in Healthy Japanese Men

Background

Gastroprotective agents are recommended for patients receiving low-dose aspirin (LDA) or nonsteroidal anti-inflammatory drugs (NSAIDs). Vonoprazan is a potassium-competitive acid blocker recently approved for the prevention of peptic ulcer recurrence in patients receiving LDA or NSAIDs.

Methods

This phase 2, open-label, single-center study in healthy Japanese males evaluated drug–drug interactions between vonoprazan 40 mg and LDA (100 mg) or NSAIDs [loxoprofen sodium (60 mg), diclofenac sodium (25 mg), or meloxicam (10 mg)] and vice versa. Subjects were allocated to one of eight cohorts and received their orally administered treatment regimen (to assess the effect of vonoprazan vs. NSAID or LDA, or vice versa) once daily. Endpoints were the pharmacokinetics of plasma concentrations of the study drugs alone and in combination (primary), safety (secondary), and vonoprazan effects on aspirin-mediated inhibition of platelet-aggregation.

Results

Of 109 subjects screened, 64 were assigned to one of eight cohorts (n = 8 per cohort) and received treatment, one subject discontinued due to a treatment-emergent adverse event (TEAE), and 63 completed the study. There were few differences in the pharmacokinetics of vonoprazan when administered with LDA or NSAIDs, and few differences in the pharmacokinetics of LDA or NSAIDs when administered with vonoprazan. The differences were small and not clinically meaningful. Inhibition of arachidonic-induced platelet aggregation by LDA was not influenced by vonoprazan. Six patients experienced a TEAE, all were mild and were deemed unrelated to study drugs. One subject withdrew due to infection (tonsillitis).

Conclusions

No clinically meaningful drug–drug interactions were observed and vonoprazan was well tolerated when administered with LDA or NSAIDs.

Study registration

JapicCTI-153100

Electronic supplementary material

The online version of this article (doi:10.1007/s40261-016-0455-2) contains supplementary material, which is available to authorized users.

Randomised clinical trial: mucosal protection combined with acid suppression in the treatment of non-erosive reflux disease - efficacy of Esoxx, a hyaluronic acid-chondroitin sulphate based bioadhesive formulation

BACKGROUND

Several studies have shown that patients with non-erosive reflux disease (NERD) are less responsive to proton pump inhibitors (PPIs) than those with erosive disease as they belong to different subgroups, in whom factors other than acid can trigger symptoms.

AIM

To evaluate whether combined therapy (mucosal protection plus acid suppression) would improve symptom relief compared to PPI treatment alone.

METHODS

In a multicenter, randomised, double-blind trial, 154 patients with NERD were randomised to receive Esoxx (Alfa Wassermann, Bologna, Italy), a hyaluronic acid-chondroitin sulphate based bioadhesive formulation, or placebo, in addition to acid suppression with standard dose PPIs for 2 weeks. Symptoms (heartburn, acid regurgitation, retrosternal pain and acid taste in the mouth) and health-related quality of life (HRQL) were evaluated before and after treatment. The primary endpoint was the proportion of patients with at least a 3-point reduction in the total symptom score.

RESULTS

At the end of treatment, the primary endpoint was reached by 52.6% of patients taking Esoxx compared to 32.1% of those given placebo (P < 0.01). The same was true also for HRQL, evaluated by means of the Short Form-36 questionnaire, which improved with both treatments, but some items were significantly better after Esoxx plus PPI therapy.

CONCLUSION

The synergistic effect of Essox with PPI treatment suggests that mucosal protection added to acid suppression could improve symptoms and HRQL in NERD patients.

Potassium-competitive acid blockers: Advanced therapeutic option for acid-related diseases

Acid-related diseases (ARDs), such as peptic ulcers and gastroesophageal reflux disease, represent a major health-care concern. Some major milestones in our understanding of gastric acid secretion and ARD treatment reached during the last 50years include 1) discovery of histamine H₂-receptors and development of H₂-receptor antagonists, 2) identification of H⁺,K⁺-ATPase as the parietal cell proton pump and development of proton pump inhibitors (PPIs), and 3) identification of Helicobacter pylori (H. pylori) as the major cause of peptic ulcers and development of effective eradication regimens. Although PPI treatments have been effective and successful, there are limitations to their efficacy and usage, i.e. short half-life, insufficient acid suppression, slow onset of action, and large variation in efficacy among patients due to CYP2C19 metabolism. Potassium-competitive acid blockers (P-CABs) inhibit H⁺,K⁺-ATPase in a reversible and K⁺-competitive manner, and exhibit almost complete inhibition of gastric acid secretion from the first dose. Many pharmaceutical companies have tried to develop P-CABs, but most of their clinical development has been discontinued due to safety concerns or a similar efficacy to PPIs. Revaprazan was developed in Korea and was the first P-CAB approved for sale. Vonoprazan, approved in 2014 in Japan, has a completely different chemical structure and higher pKa value compared to other P-CABs, and exhibits rapid onset of action and prolonged control of intragastric acidity. Vonoprazan is an effective treatment for ARDs that is especially effective in healing reflux esophagitis and for H. pylori eradication. P-CABs, such as vonoprazan, promise to further improve the management of ARDs.

Randomised clinical trial: vonoprazan, a novel potassium-competitive acid blocker, vs. lansoprazole for the healing of erosive oesophagitis

BACKGROUND

Vonoprazan is a novel potassium-competitive acid blocker which may provide clinical benefit in acid-related disorders.

AIM

To verify the non-inferiority of vonoprazan vs. lansoprazole in patients with erosive oesophagitis (EE), and to establish its long-term safety and efficacy as maintenance therapy.

METHODS

In this multicentre, randomised, double-blind, parallel-group comparison study, patients with endoscopically confirmed EE (LA Classification Grades A-D) were randomly allocated to receive vonoprazan 20 mg or lansoprazole 30 mg once daily after breakfast. The primary endpoint was the proportion of patients with healed EE confirmed by endoscopy up to week 8. In addition, subjects who achieved healed EE in the comparison study were re-randomised into a long-term study to investigate the safety and efficacy of vonoprazan 10 or 20 mg as maintenance therapy for 52 weeks.

RESULTS

Of the 409 eligible subjects randomised, 401 completed the comparison study, and 305 entered the long-term maintenance study. The proportion of patients with healed EE up to week 8 was 99.0% for vonoprazan (203/205) and 95.5% for lansoprazole (190/199), thus verifying the non-inferiority of vonoprazan (P < 0.0001). Vonoprazan was also effective in patients with more severe EE (LA Classification Grades C/D) and CYP2C19 extensive metabolisers. In the long-term maintenance study, there were few recurrences (<10%) of EE in patients treated with vonoprazan 10 or 20 mg. Overall, vonoprazan was well-tolerated.

CONCLUSIONS

The non-inferiority of vonoprazan to lansoprazole in EE was verified in the comparison study, and vonoprazan was well-tolerated and effective during the long-term maintenance study.

Potassium-Competitive Acid Blockers (P-CABs): Are They Finally Ready for Prime Time in Acid-Related Disease?

The need for new acid suppressing agents with improved pharmacology and superior antisecretory effects to address unmet clinical needs in acid-related disorders has been evident for over a decade. Recent new antisecretory drugs (IR-omeprazole and MR-dexlansoprazole) only provide a small incremental advance in control of acid secretion over the delayed-release proton pump inhibitors. Vonoprazan (a new potassium-competitive acid blocker) displays more potent and extended 24 h acid suppression and preliminary Japanese trials translate this into meaningful clinical benefits in gastro-esophageal reflux disease and Helicobacter pylori eradication. We review the vonoprazan information to date and the indications, benefits, and concerns of more effective therapeutic control of acid secretion.

Randomised clinical trial: a dose-ranging study of vonoprazan, a novel potassium-competitive acid blocker, vs. lansoprazole for the treatment of erosive oesophagitis

BACKGROUND

The potassium-competitive acid blocker vonoprazan (VPZ) has potent acid-inhibitory effects and may offer clinical advantages over conventional therapy for acid-related disorders.

AIM

To investigate the efficacy and safety of VPZ in patients with erosive oesophagitis (EO).

METHODS

In this multicentre, randomised, double-blind, parallel-group, dose-ranging study, patients ≥20 years with endoscopically confirmed EO [Los Angeles (LA) grades A-D] received VPZ 5, 10, 20 or 40 mg, or lansoprazole (LPZ) 30 mg once daily for 8 weeks. The primary endpoint was the proportion of healed EO subjects as shown by endoscopy at week 4.

RESULTS

A total of 732 subjects received VPZ or LPZ. The proportion of healed EO subjects at week 4 was 92.3%, 92.5%, 94.4%, 97.0% and 93.2%, respectively, with VPZ 5, 10, 20 and 40 mg and LPZ 30 mg. All VPZ doses were non-inferior to LPZ when adjusted for baseline LA grades A/B and C/D. Among those with LA grades C/D, the proportions of healed EO subjects were 87.3%, 86.4%, 100%, 96.0% and 87.0%, respectively, with VPZ 5, 10, 20 and 40 mg and LPZ 30 mg. The incidence of adverse events was similar across the groups.

CONCLUSIONS

Vonoprazan was effective and non-inferior to LPZ in healing EO. VPZ 20 mg or higher was highly efficacious for severe EO (LA grades C/D). VPZ was associated with no safety concern during this 8-week study, while there was a dose-dependent increase in serum gastrin. Once-daily VPZ 20 mg is the recommended clinical dose for treating EO.

Patients with refractory reflux symptoms: What do they have and how should they be managed?

With the widespread use of proton pump inhibitors (PPIs), the frontier of treating reflux disease has shifted from refractory esophagitis to PPI-refractory symptoms. However, symptoms are inherently less specific than mucosal disease and, as noted by Herregods et al. in their contribution appearing in this issue of Neurogastroenterology and Motility, patients with refractory gastroesophageal reflux disease (GERD) symptoms often do not have GERD. This review discusses potential etiologies for PPI-refractory symptoms. Three major concepts are explored: subendoscopic esophagitis, weakly acidic reflux events, and alternative explanations for persistent symptoms. With respect to subendoscopic esophagitis and unsuppressed reflux, ample evidence exists that these are present in PPI-refractory patients. The problem is that these findings are also often present in substantial numbers of individuals with a satisfactory response to PPI therapy. Hence, the emphasis shifts to determinants of symptom perception. The major conclusion of the review is that psychogenic factors such as hyperalgesia, allodynia, hypervigilance, and heightened anxiety are the most plausible explanations as the dominant determinants of PPI-refractory symptoms.

Synthetic studies of five-membered heteroaromatic derivatives as potassium-competitive acid blockers (P-CABs)

On the basis of a series of novel and potent potassium-competitive acid blockers represented by 1-sulfonylpyrrole derivative 7, we prepared several five-membered heterocyclic analogues (8) and evaluated their H(+),K(+)-ATPase activities in vitro. We also assessed the role of the methylaminomethyl side chain by comparison with methylamino and ethylamino derivatives. We observed that the five-membered core ring and its orientation affect inhibitory activity and that the methylaminomethyl moiety is the best side chain. On the basis of potency and ligand-lipophilicity efficiency, compound 7 remains the most drug-like of the compounds studied to date. This study revealed the factors necessary for potent H(+),K(+)-ATPase inhibition, such as differences in electron density, the properties of the lone pair at each apical position of the heteroaromatic ring, and the geometry of the substituents.

Challenges of correlating pH change with relief of clinical symptoms in gastro esophageal reflux disease: a phase III, randomized study of Zegerid versus Losec

Background

Zegerid (on demand immediate-release omeprazole and sodium bicarbonate combination therapy) has demonstrated earlier absorption and more rapid pH change compared with Losec (standard enteric coated omeprazole), suggesting more rapid clinical relief of heartburn. This Phase III, multicenter, double-blind, double-dummy, randomized study assessed the clinical superiority of Zegerid versus Losec for rapid relief of heartburn associated with gastro-esophageal reflux disease (GERD).

Methods

Patients with a history of frequent (2 3 days/week) uncomplicated GERD, were randomized to receive Zegerid (20mg) or Losec (20mg) with corresponding placebo. Study medication was self-administered on the first episode of heartburn, and could be taken for up to 3 days within a 14 day study period. Heartburn severity was self assessed up to 180 minutes post dose (9 point Likert scale). Primary endpoint was median time to sustained response (≥3 point reduction in heartburn severity for ≥45 minutes).

Results

Of patients randomized to Zegerid (N=122) or Losec (N=117), 228/239 had recorded ≥1 evaluable heartburn episodes and were included in the modified intent-to-treat population. No significant between-group differences were observed for median time to sustained response (60.0 vs. 52.2 minutes, Zegerid [N=117] and Losec [N=111], respectively), sustained partial response (both, 37.5 minutes) and sustained total relief (both, 105 minutes). Significantly more patients treated with Zegerid reached sustained total relief within 0–30 minutes post dose in all analysis sets (p<0.05). Both treatments were well tolerated and did not raise any safety concerns.

Conclusions

Superiority of Zegerid over Losec for rapid heartburn relief was not demonstrated; both treatments were equally effective however the rapid onset of action of Losec was unexpected. Factors, including aspects of study design may have contributed to this. This study supports previously reported difficulty in correlating intra-gastric pH change with clinical effect in GERD therapy, highlighting the significance of several technical considerations for studies of this type.

Trial registration

ClinicalTrials.gov NCT01493089

Predictors of either rapid healing or refractory reflux oesophagitis during treatment with potent acid suppression

BACKGROUND

Little is known regarding patient characteristics that influence the speed of reflux oesophagitis (RO) healing.

AIM

To investigate patient characteristics that may influence RO healing rates.

METHODS

A post hoc analysis of clinical trial data for potent acid suppression treatment of RO (esomeprazole or AZD0865) was conducted. Group A underwent endoscopy at baseline, week 2 and 4, and group B at baseline, week 4 and 8. Group A patients were sub-grouped as 'rapid' (healed at 2 weeks) or unhealed at 2 weeks. Group B patients were sub-grouped as 'slow' (healed at 8 weeks, not at 4 weeks) or 'refractory' (not healed at 8 weeks). Logistic regression analysis was performed only for comparisons within group A.

RESULTS

At 2, 4 and 8 weeks, RO had healed in 68%, 65% and 61% of patients unhealed at previous endoscopy, respectively. Low-grade [vs. high-grade (C or D)] RO was the only independent predictor of rapid healing in group A after logistic regression analysis. Significantly more rapid healers had low grade RO (A or B) at baseline than patients with refractory RO (84% vs. 49%; P < 0.001), and significantly more refractory patients had frequent regurgitation at baseline than slow healers (80% vs. 63%; P = 0.039).

CONCLUSIONS

Low- (vs. high-) grade RO determines the most rapid benefit from acid suppression. Roughly two-thirds of patients healed with each time increment of potent acid suppression therapy. This suggests that some unhealed patients may still heal with continued therapy and that truly refractory RO is rare. (ClinicalTrials.gov: NCT00206245).

Treatment of GORD: Three decades of progress and disappointments

The treatment of GORD has been revolutionized by the introduction, in the 1980s, of proton-pump inhibitors as the mainstay of medical therapy and by the development of laparoscopic antireflux surgery which has definitively replaced open surgery. However, despite these major advances, many unmet therapeutic needs still persist and justify novel therapeutic approaches. The aim of this historical review is to recall the main discoveries in the treatment of GORD that have occurred during the last three decades and to discuss why some initially promising drugs or techniques have not translated into clinical applications. A careful analysis of these previous disappointing experiences should help to identify high priorities and better research programmes on the management of GORD.

Impact of regurgitation on health-related quality of life in gastro-oesophageal reflux disease before and after short-term potent acid suppression therapy

OBJECTIVE

Limited data exist on the impact of regurgitation on health-related quality of life (HRQOL) in gastro-oesophageal reflux disease (GORD). We assessed the relationship between regurgitation frequency and HRQOL before and after acid suppression therapy in GORD.

METHOD

We used data from two randomised trials of AZD0865 25-75 mg/day versus esomeprazole 20 or 40 mg/day in non-erosive reflux disease (NERD) (n=1415) or reflux oesophagitis (RO) (n=1460). The Reflux Disease Questionnaire was used to select patients with frequent and intense heartburn for inclusion and to assess treatment response. The Quality of Life in Reflux and Dyspepsia (QOLRAD) questionnaire was used to assess HRQOL.

RESULTS

At baseline, 93% of patients in both the NERD and RO groups experienced regurgitation. Mean QOLRAD scores were similar for NERD and RO at baseline and at week 4 and disclosed decremental HRQOL with increasing frequency of regurgitation; a clinically relevant difference of >0.5 in mean QOLRAD scores was seen with regurgitation ≥4 days/week versus <4 days/week. The prevalence of frequent, persistent regurgitation (≥4 days/week) at week 4 among heartburn responders (≤1 day/week of mild heartburn) was 28% in NERD and 23% in RO. QOLRAD scores were higher among heartburn responders. There was a similar pattern of impact related to regurgitation frequency in heartburn responders compared with the group as a whole.

CONCLUSIONS

Frequent regurgitation was associated with a clinically relevant, incremental decline in HRQOL beyond that associated with heartburn before and after potent acid suppression in both NERD and RO.

CLINICAL TRIAL NUMBERS

NCT00206284 and NCT00206245.

Medical treatments of GERD: the old and new

The mainstay of pharmacological therapy for GERD is gastric acid suppression with proton pump inhibitors (PPIs), which are superior to histamine-2 receptor antagonists for healing erosive esophagitis and achieving symptomatic relief. However, up to one-third of patients may not respond to PPI therapy, creating the need for alternative treatments. Potential approaches include transient lower esophageal sphincter relaxation inhibitors, augmentation esophageal defense mechanisms by improving esophageal clearance or enhancing epithelial repair, and modulation of sensory pathways responsible for GERD symptoms. This review discusses the effectiveness of acid suppression and the data on alternative pharmacological approaches for the treatment of GERD.

Long lasting inhibitors of the gastric H,K-ATPase

Proton pump inhibitors (PPIs) are acid-activated prodrugs which covalently bind to the gastric H,K-ATPase on its luminal surface. Only active pumps can be inhibited. The short plasma residence time of current PPIs prevents inhibition of pumps synthesized or activated after the PPI has disappeared, limiting the degree of acid inhibition even with BID administration. PPIs with a longer residence time should improve acid control. Various K(+) competitive inhibitors of the pump are being developed (APAs or PCABs), with the advantage of complete inhibition of acid secretion independent of pump activity. Early data on these suggest that twice a day administration would improve acid control compared to PPIs.

New and future drug development for gastroesophageal reflux disease

Medical therapy remains the most popular treatment for gastroesophageal reflux disease (GERD). Whilst interest in drug development for GERD has declined over the last few years primarily due to the conversion of most proton pump inhibitor (PPI)'s to generic and over the counter compounds, there are still numerous areas of unmet needs in GERD. Drug development has been focused on potent histamine type 2 receptor antagonist's, extended release PPI's, PPI combination, potassium-competitive acid blockers, transient lower esophageal sphincter relaxation reducers, prokinetics, mucosal protectants and esophageal pain modulators. It is likely that the aforementioned compounds will be niched for specific areas of unmet need in GERD, rather than compete with the presently available anti-reflux therapies.

Symptomatic gastroesophageal reflux disease among Uygur residents in Urumqi: An epidemiological study and preventive treatment

AIM: To explore the prevalence of symptomatic gastroesophageal reflux disease (GERD) and reflux esophagitis (RE) in a Uygur adult population in Urumqi, to identify the risk factors for GERD, and to explore the preventive treatment of this disease in some patients.

METHODS: A total of 3000 Uygur residents aged from 18 to 78 years old were studied, and 2980 patients completed the study. This study was performed by clustering, stratifying and simple random sampling. Symptom scores were calculated using the GerdQ scale (the highest score is 18). GerdQ score ≥ 8 indicated the presence of symptomatic GERD. Subjects with a GerdQ score ≥ 8 were included in the observation group, and those with a GerdQ score < 8 were assigned to the control group. A case-control study was also performed in some subjects to confirm the diagnosis of GERD and RE. Multivariable logistic regression analysis was performed to analyze risk factors for GERD. In addition, 53 subjects with GERD were divided into an esomeprazole group, a cimetidine group, and a lifestyle changes group to receive 4 weeks of treatment, and the treatment effects were compared.

RESULTS: Of 2980 subjects who completed the survey, 468 (15.6%) had symptomatic GER (GerdQ score ≥ 8), and the male-to-female ratio was 1.07:1. The correct incidence was 72.86%. Estimated prevalence for GERD and RE was 11.44% and 2.92%, respectively. High-fat diet (OR = 7.964), drinking (OR = 3.804), drinking strong tea (OR = 2.758), abdominal obesity (OR = 2.713), greasy food (OR = 2.408) and Helicobacter pylori infection (OR = 0.186) were factors associated with the development of GERD. The rates of symptom improvement for the esomeprazole group, cimetidine group and lifestyle change group were 88.24%, 47.06% and 26.32%, respectively.

CONCLUSION: GERD is a multi-factorial disease. High-fat diet, drinking, drinking strong tea, abdominal obesity, and greasy food are risk factors for GERD, while Helicobacter pylori infection is a protective factor for GERD. Changing eating habits and lifestyle is helpful in controlling GERD.

Current pharmacological management of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD), a common disorder with troublesome symptoms caused by reflux of gastric contents into the esophagus, has adverse impact on quality of life. A variety of medications have been used in GERD treatment, and acid suppression therapy is the mainstay of treatment for GERD. Although proton pump inhibitor is the most potent acid suppressant and provides good efficacy in esophagitis healing and symptom relief, about one-third of patients with GERD still have persistent symptoms with poor response to standard dose PPI. Antacids, alginate, histamine type-2 receptor antagonists, and prokinetic agents are usually used as add-on therapy to PPI in clinical practice. Development of novel therapeutic agents has focused on the underlying mechanisms of GERD, such as transient lower esophageal sphincter relaxation, motility disorder, mucosal protection, and esophageal hypersensitivity. Newer formulations of PPI with faster and longer duration of action and potassium-competitive acid blocker, a newer acid suppressant, have also been investigated in clinical trials. In this review, we summarize the current and developing therapeutic agents for GERD treatment.

Management of the patient with incomplete response to PPI therapy

Proton pump inhibitors (PPIs) remove most of the acid from the gastroesophageal refluxate. However, PPIs do not eliminate reflux and the response of specific GERD symptoms to PPI therapy depends on the degree to which acid drives those symptoms. PPIs are progressively less effective for heartburn, regurgitation, chest pain and extra-oesophageal symptoms. Hence, with an incomplete PPI response, obtaining an accurate history, detailing which symptoms are 'refractory' and exactly what evidence exists linking these symptoms to GERD is paramount. Reflux can continue to cause symptoms despite PPI therapy because of persistent acid reflux or weakly acidic reflux. Given these possibilities, diagnostic testing (pH or pH-impedance monitoring) becomes essential. Antireflux surgery is an alternative in patients if a clear relationship is established between persistent symptoms, particularly regurgitation, and reflux. Treating visceral hypersensitivity may also benefit the subset of GERD patients whose symptoms are driven by this mechanism.

Novel therapeutics for gastro-esophageal reflux symptoms

Approximately 20-30% of patients with gastro-esophageal reflux symptoms report inadequate symptom relief while on proton-pump inhibitor therapy. The mechanisms involved are failure of the antireflux barrier (transient lower esophageal sphincter relaxations), high proximal extent of the refluxate, esophageal hypersensitivity and impaired mucosal integrity. Persisting acid or nonacid reflux can be demonstrated in 40-50% of cases, suggesting that there is room for antireflux therapy in these patients. New antireflux compounds have been shown to decrease the occurrence of transient lower esophageal sphincter relaxations. The most promising classes of compounds are GABA type B agonists and metabotropic glutamate receptor 5 antagonists, which can reduce both reflux episodes and symptoms, but the development of these compounds has been abandoned for either safety issues or lack of efficacy. Esophageal hypersensitivity and impaired mucosal integrity may prove to be relevant therapeutic targets in the future.

Gastric acid, calcium absorption, and their impact on bone health

Calcium balance is essential for a multitude of physiological processes, ranging from cell signaling to maintenance of bone health. Adequate intestinal absorption of calcium is a major factor for maintaining systemic calcium homeostasis. Recent observations indicate that a reduction of gastric acidity may impair effective calcium uptake through the intestine. This article reviews the physiology of gastric acid secretion, intestinal calcium absorption, and their respective neuroendocrine regulation and explores the physiological basis of a potential link between these individual systems.

Concomitant symptoms itemized in the Reflux Disease Questionnaire are associated with attenuated heartburn response to acid suppression

OBJECTIVES

The Reflux Disease Questionnaire (RDQ) contains six symptom items for diagnosing and gauging gastroesophageal reflux disease (GERD) severity. However, clinical trials have generally focused only on the "substernal burning" item and limited data exist on the effect of concomitant items on the treatment response of "substernal burning".

METHODS

Data from two large randomized trials of AZD0865 25-75 mg/day vs. esomeprazole 20 or 40 mg/day in patients with GERD defined by moderate to severe (≥ 4 days per week) "substernal burning" (non-erosive reflux disease (NERD), N = 1,460; reflux esophagitis (RE), N = 1,514) were re-analyzed. As no differences were found between drugs or doses in treatment response of "substernal burning", pooled data were used to determine the impact of additional RDQ items on the response of "substernal burning" to acid suppression.

RESULTS

At baseline, patients reported an average of four RDQ items. "Substernal burning" was the most responsive to therapy in the 3.3% of individuals with this as their only baseline RDQ symptom. The report of any other RDQ item was associated with a reduction in the responsiveness of "substernal burning" to acid suppression (e.g., RE patients with high severity "dyspepsia-pain" had an odds ratio of 0.20 for an improvement in "substernal burning" to treatment).

CONCLUSIONS

Other concomitant RDQ items, particularly "substernal pain" or "dyspepsia-pain", were associated with a reduced treatment effect of acid suppression on "substernal burning". These findings support the use of a more comprehensive assessment of disease state and treatment response in GERD trials and clinical practice.

Poor effectiveness of proton pump inhibitors in non-erosive reflux disease: the truth in the end!

Despite acid secretion being normal in the majority of patients with gastro-esophageal reflux disease (GERD) or Barrett's esophagus, acid inhibition represents the mainstay of treatment for both these conditions, with the aim of reducing the aggressive nature of the refluxate toward the esophageal mucosa. Proton pump inhibitors (PPIs) represent, therefore, the first choice medical treatment for GERD, in that they are able to provide an 80-85% healing rate for esophageal lesions, a 56-76% symptom relief and also reduce the incidence of complications, such as strictures as well as dysplasia and adenocarcinoma in Barrett's esophagus. According to a widely quoted systematic review, compared to patients with erosive esophagitis, patients with non-erosive reflux disease (i.e., NERD) display a reduced symptom relief with PPIs, with about 20% reduction of therapeutic gain. In this issue of NeuroGastroenterology & Motility, Weijenborg et al. address for the first time the PPI efficacy in subpopulations of patients with NERD. The study shows clearly that, when the diagnosis is accurately made by including a functional test, NERD patients respond to PPI therapy in a similar way to those with erosive disease. Although not as frequent as previously suggested, however, PPI-refractory heartburn does exist. Some 20% (range: 15-27%) of correctly diagnosed and appropriately treated patients do not respond to PPI treatment at standard doses. Although the pathophysiology underlying PPI failure in GERD is complex and likely multifactorial, acid (be it the sole component of refluxate or not) still remains a major causative factor. A better and more predictable form of acid suppression should therefore be pursued.

Evolving pharmacological approaches in gastroesophageal reflux disease

INTRODUCTION

Proton pump inhibitors (PPIs) have considerably improved quality of life in patients with gastroesophageal reflux disease (GERD). However, many patients remain symptomatic despite standard PPI therapy.

AREAS COVERED

This review focuses on evolving therapeutic strategies related to the pathophysiological processes of GERD and insufficient response to PPIs. Several clinical trials evaluated new PPI formulations and newer types of acid-suppressive drugs. These studies have evaluated traditional end points in GERD, but have not shown clinical superiority to current PPIs. Novel therapeutic strategies targeting underlying mechanisms of GERD, such as transient lower esophageal sphincter relaxations (TLESRs) and esophageal hypersensitivity, are being developed for add-on therapy to PPIs. Prokinetic drugs may also have some potential in the add-on treatment of GERD with insufficient response to PPIs. Add-on studies are hampered by insufficient information on optimal patient selection and lack of established end points.

EXPERT OPINION

Newer drugs for symptomatic control in GERD have largely focused on improved acid suppression, without evidence of clinical superiority. Drugs targeting esophageal motility and sensitivity to be used as add-onc therapy in PPI insufficient responders have not reached Phase III trials to date, due to difficulties with patient selection, tolerability and end points.

Current trends in the management of gastroesophageal reflux disease: a review

Gastroesophageal reflux disease (GERD) is a chronic disorder of the upper gastrointestinal tract with global distribution. The incidence is on the increase in different parts of the world. In the last 30 to 40 years, research findings have given rise to a more robust understanding of its pathophysiology, clinical presentation, and management. The current definition of GERD (The Montreal definition, 2006) is not only symptom-based and patient-driven, but also encompasses esophageal and extraesophageal manifestations of the disease. The implication is that the disease can be confidently diagnosed based on symptoms alone. Nonerosive reflux disease (NERD) remains the predominant form of GERD. Current thinking is that NERD and erosive reflux disease (ERD) are distinct phenotypes of GERD rather than the old concept which regarded them as components of a disease spectrum. Non erosive reflux disease is a very heterogeneous group with significant overlap with other functional gastrointestinal disorders. There is no gold standard for the diagnosis of GERD. Esophageal pH monitoring and intraluminal impedance monitoring have thrown some light on the heterogeneity of NERD. A substantial proportion of GERD patients continue to have symptoms despite optimal PPI therapy, and this has necessitated research into the development of new drugs. Several safety concerns have been raised about chronic use of proton pump inhibitors but these are yet to be substantiated in controlled studies. The debate about efficacy of long-term medical treatment compared to surgery continues, however, recent data indicate that modern surgical techniques and long-term PPI therapy have comparable efficacy. These and other issues are subjects of further research.

Regurgitation is less responsive to acid suppression than heartburn in patients with gastroesophageal reflux disease

BACKGROUND & AIMS

Although most patients with gastroesophageal reflux disease (GERD) achieve substantial symptom relief with acid suppression, many have some residual symptoms. We evaluated the responsiveness of regurgitation, characterized by the reflux disease questionnaire (RDQ) to potent acid suppression.

METHODS

We analyzed data from 2 randomized controlled trials of AZD0865 (a potassium-competitive acid blocker) 25-75 mg/day vs esomeprazole 20-40 mg/day for the treatment of nonerosive reflux disease (NERD, n = 1460) or reflux esophagitis (RE, n = 1514). Inclusion criteria for both studies were high-severity substernal burning (≥4 days per week of at least moderate intensity) during the week before enrollment. Pooled data from all treatment arms were used to ascertain the response of the reflux disease questionnaire regurgitation items to potent acid suppression during the fourth week of treatment.

RESULTS

When the study began, 93% of patients with NERD or RE had either "acid taste in the mouth" (regurgitation-taste) or "unpleasant movement of material upwards from the stomach" (regurgitation-movement). Either or both symptoms were present and severe in 53% of NERD (n = 717) and 54% of RE patients (n = 751) for the main study outcome. During week 4 of therapy, patients with severe "regurgitation-taste" and "regurgitation-movement" responded significantly less well than patients with NERD and high severity "substernal burning" (34% and 26% vs 49%) or those with RE (44% and 33% vs 55%). There were no differences in symptom response between patients with healed and nonhealed RE.

CONCLUSIONS

Regurgitation was less responsive to acid suppression than heartburn in patients with gastroesophageal reflux disease, indicating that persistent regurgitation is a common cause of incomplete treatment response.