CYP2C19 genotype is associated with symptomatic recurrence of GERD during maintenance therapy with low-dose lansoprazole. Eur J Clin Pharmacol. 2009;65:693-698. [PMID: 19259653 DOI: 10.1007/s00228-009-0628-5]

A Pharmacogenetics-Based Approach to Managing Gastroesophageal Reflux Disease: Current Perspectives and Future Steps

Proton pump inhibitors (PPIs) are commonly used medications to treat acid-related conditions, including gastro-esophageal reflux disease (GERD). Gastroenterology guidelines mention the importance of CYP2C19 in PPI metabolism and the influence of CYP2C19 genetic variations on variable responses to PPIs, but do not currently recommend the genotyping of CYP2C19 prior to prescribing PPIs. There are strong data to support the influence of CYP2C19 genetic variations on the pharmacokinetics of PPIs and clinical outcomes. Existing pharmacogenetic guideline recommendations for dose increases focus on H. pylori and erosive esophagitis indications, but PPIs are also the main therapy for treating GERD. Recent data suggest GERD patients being treated with a PPI may also benefit from genotype-guided dosing. We summarize the literature supporting this contention and highlight future directions for improved management of patients with GERD through precision medicine approaches.

CYP2C19 genotype variability in patients with refractory gastroesophageal reflux after per-oral endoscopic myotomy (POEM)

Background and study aims  Symptomatic gastroesophageal reflux is a recognized potential adverse event following peroral endoscopic myotomy (POEM). Proton pump inhibitors (PPIs) are an effective first-line therapy; although their efficacy can be affected by genotype cytochrome P450 2C19 (CYP2C19) variability leading to enhanced clearance of PPIs. The aim of our study was to evaluate the incidence of CYP2C19 genotype variability in POEM patients with refractory gastroesophageal reflux symptoms. Patients and methods  This was a single-center, prospective, cohort study of consecutive POEM cases during a 7-year study period (2013-2020). Reflux symptoms were assessed with the validated gastroesophageal reflux disease questionnaire (GerdQ) and objective pH testing after POEM. CYP2C19 genotype testing was obtained in all patients with refractory gastroesophageal reflux disease (GERD) symptoms, defined as an abnormal pH study and GerdQ score ≥ 8 while on PPIs twice daily. Results  POEM was performed in 325 consecutive patients (48.3 % female; mean age 57 years) during the study period. Twenty patients (6.8 %) had PPI-refractory, post-POEM gastroesophageal reflux based on their GerdQ score (median 9, range 8-11) and abnormal pH studies. CYP2C19 genotype testing identified 55 % (11/20) of these patients as being rapid metabolizers. Out of these, 9 (82 %) had improvement in clinical GERD symptoms after changing to a PPI less affected by CYP2C19 pharmacogenetics. Conclusions  Post-POEM, PPI-refractory GERD is rare. As shown in this study, rapid metabolizers commonly respond by changing to a PPI less affected by CYP2C19 pharmacogenetics, thereby reducing the risk of long-term consequences from GERD and unnecessary anti-reflux surgery.

Randomized Controlled Trial Comparing the Effects of Vonoprazan Plus Rebamipide and Esomeprazole Plus Rebamipide on Gastric Ulcer Healing Induced by Endoscopic Submucosal Dissection

Objective Gastric endoscopic submucosal dissection (ESD) is currently a standard procedure, and proton pump inhibitors (PPIs) are most commonly used to treat post-ESD ulcers. Vonoprazan, a potassium-competitive acid blocker (P-CAB), reportedly inhibits gastric acid secretions more effectively than PPIs. Combination therapy of a PPI plus rebamipide is effective for treating larger ulcers. Our goal was to evaluate the effects of vonoprazan plus rebamipide compared to esomeprazole plus rebamipide for the treatment of post-ESD ulcers. Methods First, vonoprazan plus rebamipide (V group) or esomeprazole plus rebamipide (E group) was orally administered to subjects for eight weeks. We then evaluated the ulcer healing process at four and eight weeks after the procedure using a gastric ulcer stage system and by measuring the ulcer size. Patients A total of 84 patients who underwent ESD for gastric neoplasms between September 2015 and December 2017 in Tsuchiura Kyodo General Hospital were included in this randomized controlled trial. Results The ulcer scar rates at week 4 in the V group (n=43) and E groups (n=39) were 20.9% and 15.4%, while those at week 8 were 90.7% and 92.3%, respectively. The ulcer reduction rates at week 4 in the V and E groups were 94.6% and 93.8%, and those at week 8 were 99.7% and 99.3%, respectively. The ulcer scar rates and reduction rates were not significantly different between the two groups. Conclusion Combination therapy consisting of vonoprazan plus rebamipide was not superior to that of esomeprazole plus rebamipide for post-ESD ulcer healing (UMIN000019516).

Proton pump inhibitors: from CYP2C19 pharmacogenetics to precision medicine

Introduction: Proton Pump inhibitors (PPIs) are commonly used for a variety of acid related disorders. Despite the overall effectiveness and safety profile of PPIs, some patients do not respond adequately or develop treatment related adverse events. This variable response among patients is in part due to genotype variability of CYP2C19, the gene encoding the CYP450 (CYP2C19) isoenzyme responsible for PPIs metabolism.

Areas covered: This article provides an overview of the pharmacokinetics and mechanism of action of the currently available PPIs, including the magnitude of CYPC19 contribution to their metabolism. Additionally, the role of CYP2C19 genetic variability in the therapeutic effectiveness or outcomes of PPI therapy is highlighted in details, to provide supporting evidence for the potential value of CYP2C19 genotype-guided approaches to PPI drug therapy.

Expert opinion: There is a large body of evidence describing the impact of CYP2C19 variability on PPIs and its potential role in individualizing PPI therapy, yet, CYP2C19 pharmacogenetics has not been widely implemented into clinical practice. More data are needed but CYP2C19 genotype-guided dosing of PPIs is likely to become increasingly common and is expected to improve clinical outcomes, and minimize side effects related to PPIs.

SS-MIX: A Ministry Project to Promote Standardized Healthcare Information Exchange

Objectives: To promote healthcare information exchange between providers and to allow hospital information systems (HIS) export information in standardized format (HL7 and DICOM) in an environment of widespread legacy systems, which only can export data in proprietary format.

Methods: Through the Shizuoka prefecture EMR project in 2004–2005, followed by the ministry’s SS-MIX project, many software products have been provided, which consist of 1) a standardized storage to receive HL7 v2.5 mes sages of patient demographics, prescription orders, laboratory results, and diagnostic disease in ICD-10, 2) a referral letter creation system, 3) a formatted document creation system, 4) a progress note/nursing record system, and 5) an archive/viewer to incorporate incoming healthcare data CD and allow users to view on HIS terminal. Meanwhile, other useful applications have been produced, such as adverse event reporting and clinical information retrieval. To achieve the above-mentioned objectives, these software products were created and propagated, because users can use these software products, provided that their HIS can export the above information to the standardized storage in HL7 v2.5 format.

Results: In 20 hospitals of Japan, the standardized storage has been installed and some applications have been used. As major HIS vendors are shipping HIS with HL7 export function since 2007, HIS of 594 hospitals in Japan became capable of exporting data in HL7 v2.5 format (as of March 2010).

Conclusions: In high CPOE installation rate (85% in 400+ bed hospitals), though most of them only capable of exporting data in proprietary format, prefecture and ministry projects were effective to promote healthcare information exchange between providers. The standardized storage became an infrastructure for many useful applications, and many hospitals started using them. Ministry designation of proposed healthcare standards was effective so as to allow vendors to conform their products, and users to install them.

Refractory gastroesophageal reflux disease: Current status and perspectives

Patients with gastroesophageal reflux disease (GERD) who do not respond to an 8-12 wk course of acid-suppressive therapy with a proton pump inhibitor twice daily, with symptoms such as heartburn and acid reflux symptoms persisting after therapy, can be diagnosed with refractory GERD (RGERD). It is estimated that RGERD accounts for approximately 10%-40% of all GERD cases. Due to complicated causes, the clinical recognition of RGERD is insufficient. Thanks to the advances in the basic and clinical research of RGERD in recent years, there have been updated consensus guidelines on the diagnosis and treatment of RGERD in America and Asia (including China). This paper reviews the definition, epidemiology, pathophysiology, diagnostic evaluation, and treatment of RGERD.

Pharmacogenomics-Based Point-of-Care Clinical Decision Support Significantly Alters Drug Prescribing

Changes in behavior are necessary to apply genomic discoveries to practice. We prospectively studied medication changes made by providers representing eight different medicine specialty clinics whose patients had submitted to preemptive pharmacogenomic genotyping. An institutional clinical decision support (CDS) system provided pharmacogenomic results using traffic light alerts: green = genomically favorable, yellow = genomic caution, red = high risk. The influence of pharmacogenomic alerts on prescribing behaviors was the primary endpoint. In all, 2,279 outpatient encounters were analyzed. Independent of other potential prescribing mediators, medications with high pharmacogenomic risk were changed significantly more often than prescription drugs lacking pharmacogenomic information (odds ratio (OR) = 26.2 (9.0-75.3), P < 0.0001). Medications with cautionary pharmacogenomic information were also changed more frequently (OR = 2.4 (1.7-3.5), P < 0.0001). No pharmacogenomically high-risk medications were prescribed during the entire study when physicians consulted the CDS tool. Pharmacogenomic information improved prescribing in patterns aimed at reducing patient risk, demonstrating that enhanced prescription decision-making is achievable through clinical integration of genomic medicine.

A review of medical therapy for proton pump inhibitor nonresponsive gastroesophageal reflux disease

Up to 40% of patients report persistent gastroesophageal reflux disease (GERD) symptoms despite proton pump inhibitor (PPI) therapy. This review outlines the evidence for medical therapy for PPI nonresponsive GERD. A literature search for GERD therapies from 2005 to 2015 in PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews identified 2928 unique citations. Of those, 40 unique articles specific to the impact of PPI metabolizer genotype on PPI response and the use adjunctive medical therapies were identified. Thirteen articles reported impacts on CYP genotypes on PPI metabolism demonstrating lower endoscopic healing rates in extensive metabolizers; however, outcomes across genotypes were more uniform with more CYP independent PPIs rabeprazole and esomeprazole. Twenty-seven publications on 11 adjunctive medications showed mixed results for adjunctive therapies including nocturnal histamine-2 receptor antagonists, promotility agents, transient lower esophageal sphincter relaxation inhibitors, and mucosal protective agents. Utilizing PPI metabolizer genotype or switching to a CYP2C19 independent PPI is a simple and conservative measure that may be useful in the setting of incomplete acid suppression. The use of adjunctive medications can be considered particularly when the physiologic mechanism for PPI nonresponse is suspected. Future studies using adjunctive medications with improved study design and patient enrollment are needed to better delineate medical management options before proceeding to antireflux interventions.

Associations of Acid Suppressive Therapy With Cardiac Mortality in Heart Failure Patients

Background

It has been recently reported that histamine H₂ receptor antagonists (H2RAs) are associated with impairment of ventricular remodeling and incident heart failure. In addition, favorable pleiotropic effects and adverse effects of proton pump inhibitors (PPIs) on cardiovascular disease have also been reported. We examined the associations of acid suppressive therapy using H2RAs or PPIs with cardiac mortality in patients with heart failure.

Methods and Results

In total, 1191 consecutive heart failure patients were divided into 3 groups: a non–acid suppressive therapy group (n=363), an H2RA group (n=164), and a PPI group (n=664). In the follow‐up period (mean 995 days), 169 cardiac deaths occurred. In the Kaplan–Meier analysis, cardiac mortality was significantly lower in the PPI group than in the H2RA and non–acid suppressive therapy groups (11.0% versus 21.3% and 16.8%, respectively; log‐rank P=0.004). In the multivariable Cox proportional hazards analysis, use of PPIs, but not H2RAs, was found to be an independent predictor of cardiac mortality (PPIs: hazard ratio 0.488, P=0.002; H2RAs: hazard ratio 0.855, P=0.579). The propensity‐matched 1:1 cohort was assessed based on propensity score (H2RAs, n=164; PPIs, n=164). Cardiac mortality was significantly lower in the PPI group than in the H2RA group in the postmatched cohort (log‐rank P=0.025). In the Cox proportional hazards analysis, the use of PPIs was a predictor of cardiac mortality in the postmatched cohort (hazard ratio 0.528, P=0.028).

Conclusions

PPIs may be associated with better outcome in patients with heart failure.

Factors associated with residual gastroesophageal reflux disease symptoms in patients receiving proton pump inhibitor maintenance therapy

AIM

To elucidate the factors associated with residual gastroesophageal reflux disease (GERD) symptoms in patients receiving proton pump inhibitor (PPI) maintenance therapy in clinical practice.

METHODS

The study included 39 GERD patients receiving maintenance PPI therapy. Residual symptoms were assessed using the Frequency Scale for Symptoms of GERD (FSSG) questionnaire and the Gastrointestinal Symptom Rating Scale (GSRS). The relationships between the FSSG score and patient background factors, including the CYP2C19 genotype, were analyzed.

RESULTS

The FSSG scores ranged from 1 to 28 points (median score: 7.5 points), and 19 patients (48.7%) had a score of 8 points or more. The patients’ GSRS scores were significantly correlated with their FSSG scores (correlation coefficient = 0.47, P < 0.005). In erosive esophagitis patients, the FSSG scores of the CYP2C19 rapid metabolizers (RMs) were significantly higher than the scores of the poor metabolizers and intermediate metabolizers (total scores: 16.7 ± 8.6 vs 7.8 ± 5.4, P < 0.05; acid reflux-related symptom scores: 12 ± 1.9 vs 2.5 ± 0.8, P < 0.005). In contrast, the FSSG scores of the CYP2C19 RMs in the non-erosive reflux disease patients were significantly lower than those of the other patients (total scores: 5.5 ± 1.0 vs 11.8 ± 6.3, P < 0.05; dysmotility symptom-related scores: 1.0 ± 0.4 vs 6.0 ± 0.8, P < 0.01).

CONCLUSION

Approximately half of the GERD patients receiving maintenance PPI therapy had residual symptoms associated with a lower quality of life, and the CYP2C19 genotype appeared to be associated with these residual symptoms.

Effects of esomeprazole on the healing process of post-endoscopic submucosal dissection gastric ulcers: a single arm, prospective trial

Objectives: Gastric endoscopic submucosal dissection (ESD) is currently a standard procedure. ESD enables en-bloc resection of large lesions, while inducing larger artificial ulcers to a greater extent than conventional procedures. Several studies have reported that proton pump inhibitors (PPIs) prevent delayed bleeding and expedite the artificial ulcer healing process. Esomeprazole, an S-isomer of omeprazole, is reportedly one of strongest inhibitors of gastric acid secretion. Previous studies have examined the effectiveness of esomeprazole. Our goal was to verify the effects of esomeprazole on artificial ulcers in a prospective study.

Methods: A total of 185 patients underwent ESD for gastric neoplasms at our hospital between January 2013 and June 2015. Among these 185 patients, 49 post-ESD scar lesions were included in this prospective trial. First, 20 mg esomeprazole was orally administered to all subjects before and after the procedure. We then evaluated the delayed bleeding rate and ulcer scarring rates at 4 weeks and 8 weeks after the procedure by using a gastric ulcer stage system.

Results: There was one case of delayed bleeding (2.0%). Regardless of Helicobacter pylori infection status, ulcer scarring rates at weeks 4 and 8 were respectively 28.6% (14/49) and 98% (48/49).

Conclusions: Our results suggest that oral administration of esomeprazole alone may be sufficient for prompt healing of artificial gastric ulcers induced by ESD (UMIN000009367).

Asia-Pacific consensus on the management of gastro-oesophageal reflux disease: an update focusing on refractory reflux disease and Barrett's oesophagus

OBJECTIVE

Since the publication of the Asia-Pacific consensus on gastro-oesophageal reflux disease in 2008, there has been further scientific advancement in this field. This updated consensus focuses on proton pump inhibitor-refractory reflux disease and Barrett's oesophagus.

METHODS

A steering committee identified three areas to address: (1) burden of disease and diagnosis of reflux disease; (2) proton pump inhibitor-refractory reflux disease; (3) Barrett's oesophagus. Three working groups formulated draft statements with supporting evidence. Discussions were done via email before a final face-to-face discussion. We used a Delphi consensus process, with a 70% agreement threshold, using Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria to categorise the quality of evidence and strength of recommendations.

RESULTS

A total of 32 statements were proposed and 31 were accepted by consensus. A rise in the prevalence rates of gastro-oesophageal reflux disease in Asia was noted, with the majority being non-erosive reflux disease. Overweight and obesity contributed to the rise. Proton pump inhibitor-refractory reflux disease was recognised to be common. A distinction was made between refractory symptoms and refractory reflux disease, with clarification of the roles of endoscopy and functional testing summarised in two algorithms. The definition of Barrett's oesophagus was revised such that a minimum length of 1 cm was required and the presence of intestinal metaplasia no longer necessary. We recommended the use of standardised endoscopic reporting and advocated endoscopic therapy for confirmed dysplasia and early cancer.

CONCLUSIONS

These guidelines standardise the management of patients with refractory gastro-oesophageal reflux disease and Barrett's oesophagus in the Asia-Pacific region.

Rapid metabolizer genotype of CYP2C19 is a risk factor of being refractory to proton pump inhibitor therapy for reflux esophagitis

BACKGROUND

Proton pump inhibitors (PPIs) are mainly metabolized by cytochrome P450 2C19 (CYP2C19) and used as the first-line therapy for gastroesophageal reflux disease (GERD). However, while several studies have examined the influence of CYP2C19 polymorphism on GERD treatment with PPIs, most have had small sample sizes and were conducted in a single center. Here, we used meta-analysis to investigate whether or not the CYP2C19 rapid metabolizer (RM) genotype is a risk factor for GERD patients being refractory to PPI therapy.

METHODS

PubMed and other electronic databases were systematically searched up to August 2014 using the following terms: "GERD and CYP2C19", "esophagitis and CYP2C19", and "non-erosive reflux disease and CYP2C19." Searches were limited to publications in English, and two investigators evaluated eligible studies and extracted data.

RESULTS

The total efficacy rate of PPIs for GERD, including reflux esophagitis (RE) and non-erosive reflux disease, was 56.4% (95% confidence interval [CI]; 53.9-58.9%, 870/1543) in intention-to-treat analysis and 63.8% (95%CI; 61.3-66.2%, 950/1489) in per-protocol analysis. Efficacy rates varied significantly between CYP2C19 genotypes (intention-to-treat analysis: RMs, 52.2% [315/604]; intermediate metabolizers, 56.7% [298/526]; poor metabolizers [PMs], 61.3% [138/225]; P = 0.047). Among RE patients, CYP2C19 RMs had an increased risk of being refractory to PPI therapy compared with PMs (odds ratio: 1.661, 95% CI: 1.023-2.659, P = 0.040).

CONCLUSIONS

The present meta-analysis demonstrates that CYP2C19 RMs with RE have an increased risk of being refractory to PPI therapy compared with PMs. Individualized dosing regimen with PPIs based on CYP2C19 genotype might be a valid therapeutic strategy for overcoming insufficient gastric acid inhibition.

A Case-Control Study of Esomeprazole Plus Rebamipide vs. Omeprazole Plus Rebamipide on Post-ESD Gastric Ulcers

Objectives

Endoscopic submucosal dissection (ESD) is useful for treating gastric tumors. Several trials have shown the efficacy of 4 or 8 weeks of proton pump inhibitor (PPI) administration for post-ESD ulcers. However, if the size of the post-ESD ulcer is larger than predicted, PPI administration alone might not be sufficient for the ulcer to heal within 4 weeks. There is no report about the efficacy of post-ESD gastric ulcers by esomeprazole. We examined retrospectively the efficacy of a combination therapy of esomeprazole plus rebamipide, a mucosal-protective antiulcer drug, on the acceleration of post-ESD ulcer healing comparing with omeprazole plus rebamipide.

Methods:

We reviewed the medical records of patients who underwent ESD for gastric neoplasia. We conducted a case-control study to compare the healing rates within 4 weeks effected by esomeprazole plus rebamipide (group E) and omeprazole plus rebamipide (group O). The sizes of the artificial ulcers were divided into normal-sized or large-sized.

Results:

The baseline characteristics did not differ significantly between the two groups except age and sex. Stage S1 disease was observed in 27.6% and 38.7% of patients after 4 weeks of treatment in the group E and O, respectively. In large-sized artificial ulcers, the healing rate of stage S1 in group E is significantly higher than that in group O in 4 weeks.(25% VS 0%:P = 0.02)

Conclusions:

The safety and efficacy profiles of esomeprazole plus rebamipide and omeprazole and rebamipide are similar for the treatment of ESD-induced ulcers. In large-sized ulcers, esomeprazole plus rebamipide promotes ulcer healing.

Individualized therapy for gastroesophageal reflux disease: potential impact of pharmacogenetic testing based on CYP2C19

The main therapeutic agent for gastroesophageal reflux disease (GERD) is a proton pump inhibitor (PPI). Plasma levels and the acid inhibitory effect of PPIs depend on the activity of cytochrome P450 (CYP) 2C19, which is polymorphic. Genotypes of CYP2C19 are classified into three groups: rapid metabolizers (RMs: *1/*1), intermediate metabolizers (IMs: *1/*X), and poor metabolizers (PMs: *X/*X), where *1 and X represent the wild type and the mutant allele, respectively. RMs include ultra-rapid metabolizers, who possess the CYP2C19*17 allele. The pharmacokinetics and pharmacodynamics of PPIs differ among different CYP2C19 genotype groups. Plasma PPI levels and intragastric pH values during PPI treatment are lowest in the RM group, intermediate in the IM group, and highest in the PM group. These CYP2C19-genotype-dependent differences in the pharmacokinetics and pharmacodynamics of PPIs influence the healing and recurrence of GERD during PPI treatment, suggesting the need for CYP2C19 genotype-based tailored therapy for GERD. CYP2C19 pharmacogenetics should be taken into consideration for the personalization of PPI-based therapy. However, the clinical usefulness of CYP2C19 genotype testing in GERD therapy should be verified in clinical studies.

Individualized therapy for gastroesophageal reflux disease: potential impact of pharmacogenetic testing based on CYP2C19

The main therapeutic agent for gastroesophageal reflux disease (GERD) is a proton pump inhibitor (PPI). Plasma levels and the acid inhibitory effect of PPIs depend on the activity of cytochrome P450 (CYP) 2C19, which is polymorphic. Genotypes of CYP2C19 are classified into three groups: rapid metabolizers (RMs: *1/*1), intermediate metabolizers (IMs: *1/*X), and poor metabolizers (PMs: *X/*X), where *1 and X represent the wild type and the mutant allele, respectively. RMs include ultra-rapid metabolizers, who possess the CYP2C19*17 allele. The pharmacokinetics and pharmacodynamics of PPIs differ among different CYP2C19 genotype groups. Plasma PPI levels and intragastric pH values during PPI treatment are lowest in the RM group, intermediate in the IM group, and highest in the PM group. These CYP2C19-genotype-dependent differences in the pharmacokinetics and pharmacodynamics of PPIs influence the healing and recurrence of GERD during PPI treatment, suggesting the need for CYP2C19 genotype-based tailored therapy for GERD. CYP2C19 pharmacogenetics should be taken into consideration for the personalization of PPI-based therapy. However, the clinical usefulness of CYP2C19 genotype testing in GERD therapy should be verified in clinical studies.

Gastroesophageal reflux disease--from reflux episodes to mucosal inflammation

Gastroesophageal reflux disease (GERD) affects 20-30% of the population in Western countries, and is one of the most common clinical problems in daily practice. GERD-associated functional and structural abnormalities are caused by recurrent exposure of the esophagus to acidic and nonacidic refluxate of gastric contents (containing duodenal and intestinal proteases as well as acid and gastric pepsin) from the stomach. Major progress has been made in the understanding of the molecular pathogenesis of GERD-associated mucosal inflammation, suggesting a complex and multifactorial pathogenesis and immune-mediated effects. This Review summarizes the complexity of mucosal pathogenesis, including microscopic changes, mucosal inflammation and GERD-specific molecular mediators, in the context of the clinical features and pathophysiological characteristics of GERD. The abnormal exposure of the esophagus to luminal contents leads to chronic mucosal inflammation that is characterized by the release of IL-8 specifically, as well as other proinflammatory mediators, from the esophageal mucosa. Evidence from animal studies indicates a stepwise inflammatory response by the epithelium, which attracts immune effector cells to infiltrate the mucosa. From bench to bedside, these novel molecular findings might provide new treatment options beyond current acid-suppressive therapy and the principle of inhibition of transient lower esophageal sphincter relaxation.

Update on the pharmacogenomics of proton pump inhibitors

Proton pump inhibitors (PPIs) are widely used for the treatment of gastroesophageal reflux disease as well as other acid-related disorders. PPIs are metabolized primarily via the CYP2C19 and CYP3A4 isoenzymes; their activity is influenced both by exogenous and endogenous (pharmacogenetic) factors. The CYP2C19 polymorphism affects the metabolism of PPIs, causing large individual pharmacokinetic variations. Differences in the CYP2C19-mediated metabolism can produce marked interpatient variability in acid suppression, in drug-interaction potential and in clinical efficacy. Understanding the pharmacokinetic properties of PPIs and examining the pharmacogenetic alterations may help clinicians optimize PPI therapy and administer individual treatment, especially to nonresponder patients with gastroesophageal reflux disease or ulcer or after failed eradication therapy.

Review of proton pump inhibitors for the initial treatment of heartburn: is there a dose ceiling effect?

Proton pump inhibitors (PPIs) are widely used in clinical practice. However, concerns have been expressed about their long-term use, particularly with regard to bone health, Clostridium difficile infections, and drug interactions with platelet aggregation inhibitors. There has been limited guidance for clinicians concerning appropriate dose selection of PPIs for the initial treatment of heartburn. This review explored whether published clinical trials provide evidence of a ceiling above which higher PPI doses do not provide additional clinical benefit over the lowest approved dose. All articles of randomized, controlled clinical trials in nonerosive gastroesophageal reflux disease (GERD) in which the effects of two or more doses of the same PPI on symptomatic relief of heartburn were quantified as a study endpoint were identified and analyzed through PubMed searches up to the end of September 2010. The majority of trials evaluated provided no evidence that higher PPI doses were superior to the lowest approved dose for the initial treatment of heartburn. There were no clinically relevant findings with respect to dose dependence and safety outcomes in these studies. Efficacy outcomes from the trials suggest there may be a dose ceiling effect and highlight the need for further research on the use of the lowest effective PPI doses as an appropriate strategy in the initial treatment of uncomplicated heartburn. Observational studies and some meta-analyses have suggested that long-term PPI pharmacotherapy might be associated with safety concerns, which necessitate the periodic evaluation of therapeutic benefit in terms of symptom resolution and regimen tolerability. However, evidence to date suggests that use of the lowest effective dose for the indication is not associated with significant adverse events, particularly in the short term. Clinical practice suggests that patients requiring long-term treatment should be maintained on the lowest dose necessary to control symptoms, and monitored for potentially confounding factors that may lead to safety concerns.

Proton pump inhibitor step-down therapy for GERD: A multi-center study in Japan

AIM: To investigate the predictors of success in step-down of proton pump inhibitor and to assess the quality of life (QOL).

METHODS: Patients who had heartburn twice a week or more were treated with 20 mg omeprazole (OPZ) once daily for 8 wk as an initial therapy (study 1). Patients whose heartburn decreased to once a week or less at the end of the initial therapy were enrolled in study 2 and treated with 10 mg OPZ as maintenance therapy for an additional 6 mo (study 2). QOL was investigated using the gastrointestinal symptom rating scale (GSRS) before initial therapy, after both 4 and 8 wk of initial therapy, and at 1, 2, 3, and 6 mo after starting maintenance therapy.

RESULTS: In study 1, 108 patients were analyzed. Their characteristics were as follows; median age: 63 (range: 20-88) years, sex: 46 women and 62 men. The success rate of the initial therapy was 76%. In the patients with successful initial therapy, abdominal pain, indigestion and reflux GSRS scores were improved. In study 2, 83 patients were analyzed. Seventy of 83 patients completed the study 2 protocol. In the per-protocol analysis, 80% of 70 patients were successful for step-down. On multivariate analysis of baseline demographic data and clinical information, no previous treatment for gastroesophageal reflux disease (GERD) [odds ratio (OR) 0.255, 95% CI: 0.06-0.98] and a lower indigestion score in GSRS at the beginning of step-down therapy (OR 0.214, 95% CI: 0.06-0.73) were found to be the predictors of successful step-down therapy. The improved GSRS scores by initial therapy were maintained through the step-down therapy.

CONCLUSION: OPZ was effective for most GERD patients. However, those who have had previous treatment for GERD and experience dyspepsia before step-down require particular monitoring for relapse.

[Evidence and uncertainties on the clinical use of proton pump inhibitors]

Proton pump inhibitors (PPI) are the most potent and effective drugs for the control of gastric acid secretion and constitute one of the most widely prescribed pharmacological groups worldwide. The safety and efficacy of PPI have been demonstrated in clinical practice and these drugs are currently the treatment of choice in peptic ulcer diseases, Helicobacter pylori infection, gastroesophageal reflux disease, nonsteroidal antiinflammatory drug gastropathy and functional dyspepsia. However, despite the excellent pharmacological profile of current PPI, their rapidity of action may be insufficient in some diseases, 24-hour acid inhibition is not always achieved and - to a greater or lesser extent depending on the distinct molecules of the PPI - there is interindividual variability in gastric antisecretory efficacy, depending on genetic polymorphism of CYP2C19, which could affect individual metabolism of the distinct PPI. New generations of these drugs will probably eliminate these deficiencies.

Clinical trial: rebamipide promotes gastric ulcer healing by proton pump inhibitor after endoscopic submucosal dissection--a randomized controlled study

BACKGROUND

Endoscopic submucosal dissection (ESD) is useful for treating gastric tumors. Several trials have shown the efficacy of 4 or 8 weeks of proton pump inhibitor (PPI) administration for post-ESD ulcers. However, if the size of the post-ESD ulcer is larger than predicted, PPI administration alone might not be sufficient for the ulcer to heal within 4 weeks. We examined the efficacy of a combination therapy of PPI and rebamipide, a mucosal-protective antiulcer drug, on the acceleration of post-ESD ulcer healing.

METHODS

Patients were randomly assigned to either the PPI and rebamipide therapy or the PPI alone. Sixty-two consecutive patients with gastric tumors gave informed consent for enrolling in the study. In all cases, the estimated size of the post-ESD ulcer was larger than 20 mm. Oral administration of the drug was started on the 2nd day post-ESD and continued to the 28th day.

RESULTS

All patients received the assigned pharmaceuticals and adhered well to the treatment regimen for 28 days. The endpoint ulcers reached S1 (scar stage) in 11/31 (36%) patients in the PPI-only group and in 21/31 (68%) in the combination group (P = 0.010).

CONCLUSIONS

The combination of PPI plus rebamipide was more effective than the PPI alone for treating ulcers larger than 20 mm within 4 weeks after ESD.

Maintenance therapy of gastroesophageal reflux disease

The aims of treatment of gastroesophageal reflux disease (GERD) are to cure mucosal breaks, control symptoms, and prevent complications (e.g. stricture, Barrett's esophagus, and esophageal adenocarcinoma). Proton pump inhibitors (PPIs) are known to be the best drugs to cure esophagitis; however, a highrecurrence rate of about 80% was described after the completion of initial therapy. Regretfully, not so many physicians perform maintenance therapy in clinical practice. Histamine H2 receptor antagonists have an insufficient effect in maintenance therapy compared with PPIs; therefore, they could be prescribed for mild reflux esophagitis. Several clinical trials have been conducted to investigate the efficacy of continuous PPI administration maintenance therapy for GERD. Among these trials, recent large-scale studies showed that esomeprazole was equal to or superior to other kinds of PPIs. On the other hand, on-demand PPI studies have been conducted, mainly in patients with nonerosive reflux disease or uninvestigated GERD;however, this strategy was less effective than continuous therapy in many studies. Because on-demand therapy is less expensive, it is worth confirming this strategy in further studies. Studies of maintenance therapy with investigations conducted for as long a period as 5 years have described that PPI maintenance therapy could be considered as effective, safe, and well tolerated.