Rabeprazole 10 mg q.d.s. decreases 24-h intragastric acidity significantly more than rabeprazole 20 mg b.d. or 40 mg o.m., overcoming CYP2C19 genotype

Evolving Concepts in Helicobacter pylori Management

Helicobacter pylori is the most common chronic bacterial infection worldwide and the most significant risk factor for gastric cancer, which remains a leading cause of cancer-related death globally. H pylori and gastric cancer continue to disproportionately impact racial and ethnic minority and immigrant groups in the United States. The approach to H pylori case-finding thus far has relied on opportunistic testing based on symptoms or high-risk indicators, such as racial or ethnic background and family history. However, this approach misses a substantial proportion of individuals infected with H pylori who remain at risk for gastric cancer because most infections remain clinically silent. Moreover, individuals with chronic H pylori infection are at risk for gastric preneoplastic lesions, which are also asymptomatic and only reliably diagnosed using endoscopy and biopsy. Thus, to make a significant impact in gastric cancer prevention, a systematic approach is needed to better identify individuals at highest risk of both H pylori infection and its complications, including gastric preneoplasia and cancer. The approach to H pylori eradication must also be optimized given sharply decreasing rates of successful eradication with commonly used therapies and increasing antimicrobial resistance. With growing acceptance that H pylori should be managed as an infectious disease and the increasing availability of susceptibility testing, we now have the momentum to abandon empirical therapies demonstrated to have inadequate eradication rates. Molecular-based susceptibility profiling facilitates selection of a personalized eradication regimen without necessitating an invasive procedure. An improved approach to H pylori eradication coupled with population-level programs for screening and treatment could be an effective and efficient strategy to prevent gastric cancer, especially in minority and potentially marginalized populations that bear the heaviest burden of H pylori infection and its complications.

Eradication rate and adherence with high-dose amoxicillin and proton pump inhibitor as first-line treatment for Helicobacter pylori infection: Experience from University Hospital in Chile

INTRODUCTION

In Chile, more than 70% of adults are infected by Helicobacter pylori. Clarithromycin should not be used in any regimen if there is >15% resistance to this antibiotic, being greater than 26% in our population. In this scenario, the effectiveness of triple therapy (proton pump inhibitor [PPI], clarithromycin, amoxicillin) was only 63.8%.

AIM

To evaluate the eradication rate and safety of dual therapy (esomeprazole and amoxicillin) in high doses, through a prospective, observational, and descriptive study.

METHODS

Patients with a positive urease test obtained in an upper digestive endoscopy were included. Any other previous H. pylori eradication regimen were excluded. All patients were treated with esomeprazole 40 mg three times a day and amoxicillin 750 mg four times a day for 14 days. The eradication rate of the dual therapy was evaluated with the H. pylori stool antigen test (the Pylori-Strip® test used) 6 weeks after completing the eradication treatment and with at least 14 days without PPI, being a negative result, confirmation of the effectiveness of this regimen.

RESULTS

Of 122 patients, 106 had a negative H. pylori antigen in stool; The intention-to-treat and per protocol analysis, the eradication rates were 91.8% [95% CI: 87%-97%] and 94% [95% CI: 90%-98%], respectively. Four patients discontinued treatment due to adverse effects. Smoking and adherence to treatment were associated with eradication rate.

CONCLUSIONS

In this cohort of patients with H. pylori infection, high-dose dual therapy has a high eradication rate and good adherence, raising the possibility that it could be used as first-line therapy in our country. Studies with a larger number of patients should confirm these results.

Efficacy and safety of high-dose ilaprazole-amoxicillin dual therapy for Helicobacter pylori eradication: a prospective, single-center, randomized trial

Background: Until now, there have been no randomized controlled trials directly evaluating the efficacy of high-dose ilaprazole-amoxicillin dual therapy (HT) in comparison to other standard treatments for H. pylori (Helicobacter pylori) infection. This study aimed to compare the effectiveness and safety of HT with bismuth quadruple therapy (BQT) as an initial treatment for H. pylori. Methods: This single-center, prospective, randomized clinical controlled trial recruited 225 consecutive patients. They were assigned to either HT group (ilaprazole, 10 mg, twice daily; amoxicillin 1,000 mg, three times daily) or BQT group (compound bismuth aluminate granules, 2.6 g, three times daily; ilaprazole, 5 mg, twice daily; amoxicillin, 1,000 mg, twice daily; clarithromycin, 500 mg, twice daily) for 14 days. The 13C-urea breath test assessed eradication success 4 weeks after treatment. The primary outcome focused on the eradication rate, with secondary outcomes including safety and compliance. Results: From February 2023 to March 2023, 228 subjects were screened, and 225 were randomized. The HT and BQT groups showed eradication rates of 76.3% and 61.3% (p = 0.015) both by intention-to-treat (ITT) analysis and per-protocol (PP) analysis. HT was associated with fewer adverse events than BQT (27.2% vs. 81.8%, p = 0.002). The most commonly reported adverse events was bitter taste of mouth (3.5% vs. 60.4%, p < 0.001). There was no significant difference in compliance between the two groups (89.5% vs. 92.8%, p = 0.264). Conclusion: The 14-day HT treatment demonstrates better efficacy in H. pylori eradication treatment and improved safety and compliance compared to BQT. The results provide supporting evidence for 14-day HT can be potentially considered as a first-line regimen for empirical treatment. Clinical Trial Registration: https://www.chictr.org.cn/showproj.html?proj=186562, identifier ChiCTR2200066284.

Efficacy analysis of empirical bismuth quadruple therapy, high-dose dual therapy, and resistance gene-based triple therapy as a first-line Helicobacter pylori eradication regimen - An open-label, randomized trial

This research aimed to evaluate the eradication efficacy, safety, and gastrointestinal symptom relief rates of empirical bismuth quadruple therapy, high-dose dual therapy, and resistance gene-based triple therapy in primary eradication patients in Yangzhou, China. It also investigated the possible factors influencing the success of different Helicobacter pylori eradication regimens. A single-center, prospective, open-label, randomized controlled study was performed from December 2020 and October 2021, in which 255 patients with H. pylori infection were assigned in a 1:1:1 ratio to the three different groups. Our results showed that high-dose dual therapy (91.0%, 71/78) and resistance gene-based triple therapy (94.9%, 75/79) achieved eradication rates and compliance equivalent to those of empirical bismuth quadruple therapy (85.3%, 64/75) in the per-protocol analysis, while high-dose dual therapy had lower rates of adverse events (11.5%, 9/78, P < 0.05), fewer side effects, and greater safety. Most patients' gastrointestinal discomfort symptoms improved after eradication of H. pylori. Poor compliance (P < 0.05) and antibiotic resistance (P < 0.05) were risk factors for the efficacy of H. pylori eradication. Therefore, the appropriate regimen can be individualized for eradication therapy in clinical practice according to the patient's resistance and tolerance to the drug.

Helicobacter pylori infection

Helicobacter pylori infection causes chronic gastritis, which can progress to severe gastroduodenal pathologies, including peptic ulcer, gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma. H. pylori is usually transmitted in childhood and persists for life if untreated. The infection affects around half of the population in the world but prevalence varies according to location and sanitation standards. H. pylori has unique properties to colonize gastric epithelium in an acidic environment. The pathophysiology of H. pylori infection is dependent on complex bacterial virulence mechanisms and their interaction with the host immune system and environmental factors, resulting in distinct gastritis phenotypes that determine possible progression to different gastroduodenal pathologies. The causative role of H. pylori infection in gastric cancer development presents the opportunity for preventive screen-and-treat strategies. Invasive, endoscopy-based and non-invasive methods, including breath, stool and serological tests, are used in the diagnosis of H. pylori infection. Their use depends on the specific individual patient history and local availability. H. pylori treatment consists of a strong acid suppressant in various combinations with antibiotics and/or bismuth. The dramatic increase in resistance to key antibiotics used in H. pylori eradication demands antibiotic susceptibility testing, surveillance of resistance and antibiotic stewardship.

Comparing high-dose dual therapy with bismuth-containing quadruple therapy for the initial eradication of Helicobacter pylori infection on Hainan Island: a randomized, multicenter clinical trial

BACKGROUND

Traditional bismuth-containing quadruple therapy, as a first-line eradication treatment for Helicobacter pylori (H. pylori), has several disadvantages, including drug side effects, low medication adherence, and high costs. Trials of high-dose dual treatment have demonstrated its advantages, which include good safety and adherence profiles. In this study, we investigated the efficacy, safety, and compliance of a high-dose dual therapy when compared with bismuth-based quadruple treatment for the initial eradication of H. pylori infection on Hainan Island, China.

METHODS

We randomized 846 H. pylori-infected patients into two groups. A bismuth-containing quadruple therapy group was administered the following: esomeprazole 20 mg, amoxicillin 1000 mg, and clarithromycin 500 mg twice daily, and colloidal bismuth pectin in suspension 150 mg three times/day for 2 weeks. A high-dose dual therapy group was administered the following: esomeprazole 20 mg four times/day and amoxicillin 1000 mg three times/day for 2 weeks. Patients were given a 13C urea breath test at 4 weeks at treatment end. Adverse effects and compliance were evaluated at follow-up visits.

RESULTS

Eradication rates in the high-dose dual therapy group were: 90.3% (381/422, 95% confidence interval [CI]: 87.1%-92.9%) in intention-to-treat (ITT) and 93.6% (381/407, 95% CI: 90.8%-95.8%) in per-protocol (PP) analyses. Eradication rates were 87.3% in ITT (370/424, 95% CI: 83.7%-90.3%) and 91.8% in PP analyses (370/403, 95% CI: 88.7%-94.3%) for quadruple therapy, with no statistical differences (P = 0.164 in ITT and P = 0.324 in PP analyses). Adverse effects were 13.5% (55/407) in the dual group and 17.4% (70/403) in the quadruple group (P = 0.129). Compliance was 92.4% (376/407) in the dual group and 86.6% (349/403) in the quadruple group (P = 0.007).

CONCLUSIONS

High-dose dual therapy had high eradication rates comparable with bismuth-based quadruple treatment, with no differences in adverse effects, however higher adherence rates were recorded.

A Malaysian consensus report on the diagnosis and treatment of Helicobacter pylori infection

Helicobacter pylori is one of the most common chronic bacterial infections in humans and responsible for 90% of duodenal ulcers and 70-90% of gastric ulcers. Despite this, many misconceptions regarding the appropriate diagnostic method and treatment strategies still exist in the Malaysian clinical practice. Under the initiative of the steering committee, an expert panel consisting of nine key opinion leaders in the field of gastroenterology convened to develop a set of consensus statements that are relevant to the Malaysian healthcare practice. The panel members reviewed the current evidence on the management of H. pylori infection, focusing on the best practices that are relevant to the Malaysian population based on clinical experience and published clinical evidence. Using the modified Delphi method, the panel achieved consensus in three areas of H. pylori infection management: indications for testing, diagnosis, and treatment. The panel proposed a set of 19 consensus statements, which were synthesized via two rounds of blinded voting and group discussions. The recommendations provided are relevant to the Malaysian population and can be used as a guide by physicians across various healthcare settings to facilitate appropriate diagnostic testing and treatment of H. pylori infection.

Efficacy and safety of high-dose esomeprazole and amoxicillin dual therapy versus bismuth-containing quadruple therapy for Helicobacter pylori infection: a multicenter, randomized controlled clinical trial

BACKGROUND

A high-dose proton pump inhibitor (PPI)-amoxicillin dual therapy has been investigated for treatment of patients with Helicobacter pylori (H. pylori) infection. Currently, the efficacy of this dual therapy remains inconclusive, with controversial findings from various single-center clinical trials.

OBJECTIVES

To assess the efficacy and safety of high-dose dual therapy (HDDT) compared with the bismuth-containing quadruple therapy (BQT) in treatment-naive patients with H. pylori infection.

DESIGN

A multicenter, open-label, randomized controlled clinical trial.

METHODS

Three hundred and forty treatment-naïve patients with H. pylori infection were prospectively recruited from seven participating hospitals. The enrolled patients were randomized into one of two treatment groups: the HDDT group (esomeprazole, 20 mg four times daily; amoxicillin, 750 mg four times daily) and the BQT group (esomeprazole, 20 mg, twice daily; bismuth potassium citrate, 600 mg, twice daily; amoxicillin, 1 g, twice daily; metronidazole, 400 mg, four times daily). The primary outcome was eradication rate, and secondary outcomes were safety and patient compliance.

RESULTS

The eradication rates in the HDDT group versus the BQT group were 86.47% versus 87.06% on intention-to-treat (ITT) analysis, 91.88% versus 92.50% on modified ITT (MITT) analysis, and 91.77% versus 93.04% on per-protocol (PP) analysis, with no significant differences between the two groups. The patient compliance rates in the HDDT group versus the BQT group were 97.02% versus 95.86%, and no significant difference was found between the two groups. Notably, the HDDT group exhibited significantly lower incidence in the drug-induced adverse events (AEs) compared to the BQT group (16.67% versus 47.94%).

CONCLUSION

HDDT is equally efficacious in eradicating H. pylori infection and resulted in good patient compliance and safety compared with BQT. These findings provide evidence in support of HDDT as a first-line treatment for H. pylori infection.

REGISTRATION

This clinical trial was registered at The Chinese Clinical Trial Registry (trial registration number: ChiCTR2000039096).

Optimized dual therapy for treatment-naive patients of Helicobacter pylori infection: A large-scale prospective, multicenter, open-label, randomized controlled study

BACKGROUND

The efficacy and safety of high-dose amoxicillin (AMX) and proton pump inhibitors (PPI) dual therapy raises much more attention in recent years. Comparative studies among the dual therapies are required to explore more suitable regimens. This study compared the efficacy, adverse events, and patient compliance of three different high-dose dual regimens in treatment-naive patients of Helicobacter pylori (H. pylori) infection.

MATERIALS AND METHODS

The study was a prospective, multicenter, open-label, randomized controlled trial, including H. pylori-infected treatment-naive patients at 12 tertiary hospitals in China. The eligible subjects received high-dose AMX and esomeprazole (ESO) dual therapy of different regimens. They were randomly assigned to group A (ESO 20 mg plus AMX 750 mg, Qid for 14 days), group B (ESO 40 mg Bid plus AMX 1 g Tid for 14 days), or group C (ESO 20 mg plus AMX 1 g, Tid for 14 days). The eradication rates, adverse events, and patient compliance of the three groups were compared.

RESULTS

Between April 2021 and January 2022, a total of 1080 subjects were screened and 945 were randomized. The eradication rates in groups A, B, and C were 88.6% (95% CI 84.5%-91.9%), 84.4% (95% CI 80.0%-88.3%), and 86.7% (95% CI 82.4%-90.2%; p = .315), respectively, based on intention-to-treat analysis; 90.3% (95% CI 86.4%-93.3%), 85.5% (95% CI 81.1%-89.2%), and 87.8% (95% CI 83.6%-91.2%; p = .197), respectively, according to modified intention-to-treat analysis; and 90.4% (95% CI 86.5%-93.5%), 85.8% (95% CI 81.4%-89.5%), and 88.3% (95% CI 84.1%-91.7%; p = .202) in per-protocol analysis. History of antibiotics use in 2 years reduced eradication effect in group B (ESO 40 mg Bid, AMX 1 g Tid). The modified intention-to-treat eradication rates were 81.4% vs 90.0% among those with or without a history of antibiotics use in group B (p = .031). The adverse event rates were 13.7%, 12.7%, and 12.1% in groups A, B, and C, respectively (p = .834). Patient compliance of the three groups was similar.

CONCLUSIONS

Two optimized AMX and PPI dual regimens (ESO 40 mg Bid or 20 mg Tid plus AMX 1 g Tid for 14 days) had similar efficacy, safety and compliance as compared with classical dual regimen (ESO 20 mg plus AMX 750 mg Qid for 14 days) in H. pylori-infected treatment-naive patients.

Management of Helicobacter pylori infection: the Maastricht VI/Florence consensus report

Helicobacter pyloriInfection is formally recognised as an infectious disease, an entity that is now included in the International Classification of Diseases 11th Revision. This in principle leads to the recommendation that all infected patients should receive treatment. In the context of the wide clinical spectrum associated with Helicobacter pylori gastritis, specific issues persist and require regular updates for optimised management.The identification of distinct clinical scenarios, proper testing and adoption of effective strategies for prevention of gastric cancer and other complications are addressed. H. pylori treatment is challenged by the continuously rising antibiotic resistance and demands for susceptibility testing with consideration of novel molecular technologies and careful selection of first line and rescue therapies. The role of H. pylori and antibiotic therapies and their impact on the gut microbiota are also considered.Progress made in the management of H. pylori infection is covered in the present sixth edition of the Maastricht/Florence 2021 Consensus Report, key aspects related to the clinical role of H. pylori infection were re-evaluated and updated. Forty-one experts from 29 countries representing a global community, examined the new data related to H. pylori infection in five working groups: (1) indications/associations, (2) diagnosis, (3) treatment, (4) prevention/gastric cancer and (5) H. pylori and the gut microbiota. The results of the individual working groups were presented for a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in various clinical fields.

Comparison of the Dual Therapy of Ilaprazole-Amoxicillin and the Bismuth Quadruple Therapy of Ilaprazole-Amoxicillin-Furazolidone-Bismuth Glycyrrhizinate for Eradication of Helicobacter pylori

Objective: The present study aims to compare the safety and efficacy of an amoxicillin/ilaprazole regimen with a bismuth quadruple regimen as the first-line treatment for eradicating Helicobacter pylori (H. pylori) infection.

Methods: This was an open-label, randomized, single-center study involving 450 patients with untreated H. pylori infection who were randomly assigned to an Ilaprazole-amoxicillin-furazolidone-bismuth glycyrrhizinate (IAFB) quadruple therapy group for 14 days, a bismuth quadruple therapy group for 10 days, or Ilaprazole-amoxicillin (IA) dual therapy group for 14 days. The 13C urea breath test determined that H. pylori had been eliminated 4–6 weeks after treatment. For patients who failed the first treatment, mucosal tissues (two gastric antrum and one gastric body) were taken under gastroscope for the culture of H. pylori, drug sensitivity, the CYP2C19 gene, and globular degeneration.

Results: In the intention-to-treat analysis, the eradication rates of H. pylori in the IAFB-14-day group, the IAFB-10-day group, and the IA-14-day group were 84.0, 79.3, and 88.0%, respectively. In the per-protocol analysis, the eradication rates in the three groups were 94.7, 87.5, and 93.0%, respectively. The resistance rates of patients who failed H. pylori eradication were 68.9% (22/32) for amoxicillin, 90.6% (29/32) for clarithromycin, 68.9% (22/32) for metronidazole, and 87.5% (28/32) for levofloxacin, and the extensive metabolizers of CYP2C19 polymorphism were 59.3% (19/32), the intermediate metabolizers were 34.4% (11/32), and the poor metabolizers were 6.3% (2/32).

Conclusion: For newly treated patients with H. pylori infection in China, the efficacy of IA therapy for 14 days was similar to IAFB quadruple therapy for 10 or 14 days with better compliance and less cost. Therefore, these therapies can be considered first-line regimens for empirical treatment.

Clinical Trial Registration: [http://www.chictr.org.cn/searchproj.aspx], identifier [ChiCTR2100052308].

Helicobacter pylori diagnosis and therapy in the era of antimicrobial stewardship

The diagnosis and therapy of Helicobacter pylori infection have undergone major changes based on the use the principles of antimicrobial stewardship and increased availability of susceptibility profiling. H. pylori gastritis now recognized as an infectious disease, as such there is no placebo response allowing outcome to be assessed in relation to the theoretically obtainable cure rate of 100%. The recent recognition of H. pylori as an infectious disease has changed the focus to therapies optimized to reliably achieve high cure rates. Increasing antimicrobial resistance has also led to restriction of clarithromycin, levofloxacin, or metronidazole to susceptibility-based therapies. Covid-19 resulted in the almost universal availability of polymerase chain reaction testing in hospitals which can be repurposed to utilize readily available kits to provide rapid and inexpensive detection of clarithromycin resistance. In the United States, major diagnostic laboratories now offer H. pylori culture and susceptibility testing and American Molecular Laboratories offers next-generation sequencing susceptibility profiling of gastric biopsies or stools for the six commonly used antibiotics without need for endoscopy. Current treatment recommendations include (a) only use therapies that are reliably highly effective locally, (b) always perform a test-of-cure, and (c) use that data to confirm local effectiveness and share the results to inform the community regarding which therapies are effective and which are not. Empiric therapy should be restricted to those proven highly effective locally. The most common choices are 14-day bismuth quadruple therapy and rifabutin triple therapy. Prior guidelines and treatment recommendations should only be used if proven locally highly effective.

Influence of Cytochrome P450 2C19 Genotype on Helicobacter pylori Proton Pump Inhibitor-Amoxicillin-Clarithromycin Eradication Therapy: A Meta-Analysis

Background: Proton pump inhibitors (PPIs) are the first-line treatment for acid-related diseases. The pharmacokinetics and therapeutic efficacy of PPIs, however, are influenced by genetic factors such as variants in genes encoding drug-metabolizing enzymes (e.g., cytochrome P450 2C19 [CYP2C19]) and drug transporters. We performed a meta-analysis to evaluate the influence of CYP2C19 genotype and PPI class, PPI dose, treatment duration and clarithromycin dose on the cure rate of PPI-containing Helicobacter pylori eradication therapy.

Methods: Randomized control trials (RCTs) investigating cure rates using a PPI-amoxicillin-clarithromycin regimen among different CYP2C19 genotypes through May 2021 were included.

Results: A total of 25 studies (5,318 patients) were included. The overall eradication rate in the intention-to-treat analysis was 79.0% (3,689/4,669, 95% confidence interval [CI]: 77.8–80.2%), and that in CYP2C19 extensive metabolizers (EMs), intermediate metabolizer (IMs) and poor metabolizers (PMs) was 77.7% (1,137/1,464, 95% CI: 75.3–79.6%), 81.2% (1,498/1,844, 95% CI: 79.3–83.0%) and 86.8% (644/742, 95% CI: 83.9–88.9%), respectively. Meta-analysis showed that the relaTakashitive risk of failed eradication in CYP2C19 EMs compared with IMs and PMs was 1.21 (95% CI: 1.06–1.39, P = 0.006) and 1.57 (95% CI: 1.27–1.94, P < 0.001), respectively, in the fixed-effects model. The cure rate of omeprazole and lansoprazole-containing eradication regimens differed among CYP2C19 genotypes (P < 0.05), while that of rabeprazole and esomeprazole-containing regimens was similar.

Conclusion: The cure rates of PPI-amoxicillin-clarithromycin H. pylori eradication regimen, especially those containing omeprazole and lansoprazole, differ among CYP2C19 genotypes. Therefore, selection of a second-generation PPI or tailored treatment may achieve higher eradication rates than first-generation PPI-amoxicillin-clarithromycin triple regimen.

Efficacy and Safety of Modified Dual Therapy as the First-line Regimen for the Treatment of Helicobacter pylori Infection: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

In an era of antibiotic resistance, modified dual therapy has been paid much attention because of simple drug composition and low resistance of amoxicillin. However, its eradication rate as a first-line regimen remains controversial. This study is to evaluate the efficacy and safety of modified dual therapy for the initial treatment of Helicobacter pylori (H. pylori) infection compared with mainstream first-line therapies.

METHODS

PubMed, the Cochrane Library, and Embase were searched for randomized clinical trials evaluating the efficacy and safety of modified dual therapy as the initial treatment for H. pylori eradication compared with guideline-recommended first-line therapies. A meta-analysis was conducted using Review Manager 5.3 and dichotomous data were estimated by the risk ratio (RR) with the 95% confidence interval (CI). We also performed subgroup analysis according to control groups and studies with antibiotic susceptibility tests.

RESULTS

Eight studies including 1672 patients with H. pylori infection met the selection criteria and were assessed. The meta-analysis demonstrated that modified dual therapy achieved similar efficacy [85.83% vs. 86.77%, RR 0.99 (95% CI, 0.95-1.03), intention-to-treat analysis; 89.53% vs. 90.45%, RR 0.99 (95% CI, 0.96-1.02), per-protocol analysis] and compliance [95.77% vs. 95.56%, RR 1.00 (95% CI, 0.98-1.02)] compared with recommended first-line regimens. In addition, there were no significant differences in comparing the eradication rate of modified dual therapy with clarithromycin triple therapy, bismuth quadruple therapy, and concomitant therapy, respectively. Subgroup analysis based on the studies with antibiotic susceptibility tests also confirmed a similar efficacy. However, modified dual therapy showed fewer adverse effects [8.70% vs. 22.38%, RR 0.39 (95% CI, 0.28-0.54)], with a significant difference (P<0.00001).

CONCLUSION

Modified dual therapy achieved equal efficacy and compliance compared with recommended first-line regimens for H. pylori infection, and generally modified dual therapy showed fewer side effects.

PPI-amoxicillin dual therapy four times daily is superior to guidelines recommended regimens in the Helicobacter pylori eradication therapy within Asia: A systematic review and meta-analysis

BACKGROUND

Systematic reviews suggested that the eradication efficacy of PPI-amoxicillin dual therapy is similar to that of other commonly used regimens. However, it might be affected by the medication frequency. Basic and clinical studies have shown that dual therapy administered four-times daily has a reliable pathophysiological basis and could achieve satisfactory efficacy. Therefore, a systematic review of RCTs of dual therapy and other regimens was conducted to clarify whether dual therapy is superior to guidelines recommended regimens.

MATERIALS AND METHODS

The RCTs comparing dual therapy with other regimens were subjected to meta-analysis to evaluate the eradication rate, adverse reactions, and compliance using a random-effects model.

RESULTS

Dual therapy administered four-times daily had a higher eradication rate than other regimens (intention-to-treat analysis: 89.7% vs 84.6%, OR: 1.52, 95%CI 1.08-2.14, p = 0.02; per-protocol analysis: 92.6% vs 88.2%, OR: 1.54, 95%CI 1.01-2.34, p = 0.04). In first-line therapy, according to intention-to-treat analysis, the eradication rate of dual therapy was higher than other regimens (89.8% vs 84.2%, OR: 1.63, 95%CI 1.02-2.61, p = 0.04). In per-protocol analysis, dual therapy showed better efficacy than others (92.9% vs 88.3%, OR: 1.68, 95% CI 0.98-2.89, p = 0.06), but not significantly. In salvage treatment, no significant difference was detected. The safety of dual therapy was significantly better than other regimens (19.6% vs 36.7%, p < 0.01), but no difference was observed in compliance (p = 0.58).

CONCLUSION

PPI-amoxicillin dual therapy administered four-times daily has better efficacy and safety in H. pylori eradication than current guidelines recommended regimens, especially in first-line therapy, and mainly in Asia.

The high-dose amoxicillin-proton pump inhibitor dual therapy in eradication of Helicobacter pylori infection

INTRODUCTION

More attention has been paid to the eradication therapy of Helicobactor pylori with the enhancement of health awareness of patients. However, the increasing antibiotic resistance of H. pylori, due to the wide use and abuse of antibiotics, has become a critical factor affecting the efficacy of eradication. To effectively improve the eradication rate of H. pylori, high-dose amoxicillin-proton pump inhibitor (PPI) dual therapy has recently become one of the hot issues.

AREAS COVERED

The authors review the schemes and efficacy of high-dose amoxicillin-PPI dual therapies in eradication of H. pylori infection. The review indicates that the H. pylori eradication rate of the dual therapy is overall comparable to or better than that of bismuth-containing quadruple therapy or standard triple therapy. It is more effective to administer both amoxicillin and PPI 3-4 times daily for 14 days in the high-dose amoxicillin-PPI dual therapy, and esomeprazole seems to be superior to other PPIs.

EXPERT OPINION

The high-dose amoxicillin-PPI dual therapy is currently a promising H. pylori eradication regimen in clinical practice, deserving further verification and discussion. Much more attention should be paid to the influence of CYP2C19 polymorphisms and virulence genotyping on H. pylori eradication, and the homogeneity and objectivity of the comparison among different studies.

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

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

A comparative study of 14-day dual therapy (esomeprazole and amoxicillin four times daily) and triple plus bismuth therapy for first-line Helicobacter pylori infection eradication: A randomized trial

BACKGROUND

Favorable outcomes in treating H pylori infection using "dual therapy (proton pump inhibitor and amoxicillin four times daily)" have attracted widespread attention. However, there are few reports, and the study results lack agreement. This study aimed to compare the eradication rate, safety, and compliance of naïve-treatment patients with H pylori infection on "dual therapy" with those on "triple plus bismuth (TPB) therapy."

METHODS

This is a non-inferior randomized controlled trial conducted on 760 patients with H pylori infection. The participants were randomly assigned to two eradication groups: dual therapy (esomeprazole 20 mg and amoxicillin 750 mg four times daily) and TPB therapy (esomeprazole 20 mg, amoxicillin 1000 mg, clarithromycin 500 mg, and bismuth potassium citrate 220 mg twice daily) for 14 days. Safety and compliance were assessed within 3 days after eradication. Urea breath test was performed about 8 weeks after eradication to evaluate outcome. Antibiotic resistance and CYP2C19 polymorphism were determined.

RESULTS

Compared with TPB therapy, dual therapy had significantly higher eradication rates in intention-to-treat (87.1% vs 80.5%, rate difference 6.6%), modified intention-to-treat (90.9% vs 85.5%, 5.5%) and per-protocol (92.4% vs 87.8%, 4.7%) analyses, respectively. Adverse reactions in dual therapy group were significantly lower than TPB therapy group (17.6% vs 25.5%, P = .008), and dual therapy group had better compliance (96.3% vs 92.3%, P = .019). Antibiotic resistance and poor compliance were also associated with treatment failure.

CONCLUSIONS

Dual therapy (esomeprazole and amoxicillin four times daily) was non-inferior to, and even superior to TPB therapy as first-line H pylori eradication.

Gastroesophageal reflux disease: key messages for clinicians

Gastroesophageal reflux disease (GERD) is a chronic common disorder for which patients often refer to specialists. In the last decades, numerous studies helped to clarify the pathophysiology and the natural history of this disease. Currently, in the clinical setting, GERD is defined by the presence of symptoms that, when endoscopic investigation is required, permit to distinguish between cases with or without associated esophageal mucosal injuries. These conditions are called erosive reflux disease and non-erosive reflux disease (NERD), respectively. The latter is the most common manifestation of GERD. Symptoms are defined typical, as heartburn and regurgitation, and atypical (also called extra-esophageal), as coughing and/or wheezing, hoarseness, sore throat, otitis media, and dental manifestations. In this context, it is crucial for clinicians to investigate the presence of features of suspected malignancy, as unexplained weight loss, anemia, dysphagia, persistent vomiting, familiar history of cancer, long history of GERD, and beginning of GERD symptoms after the age of 50 years. The presence of these risk factors should induce to perform an endoscopic examination. Particular attention should be given to functional conditions that can mimic GERD, such as functional heartburn and hypersensitive esophagus as well as, more rarely, eosinophilic esophagitis. The former ones have different pathophysiology and this explains the frequent non-response to proton pump inhibitor drugs. This narrative review provides to clinicians a useful and practical overview of the state-of-the-art on advancements in the knowledge of GERD.

Searching for an optimal therapy for H pylori eradication: High-dose proton-pump inhibitor dual therapy with amoxicillin vs. standard triple therapy for 14 days

BACKGROUND & AIMS

We compared a high-dose dual therapy (HDDT) with rabeprazole and amoxicillin and compared it with a standard triple therapy (STT) with rabeprazole, amoxicillin, and clarithromycin for 2 weeks for H pylori eradication in treatment naïve patients.

METHODS

H pylori-positive patients were randomly assigned to either a rabeparzole (Pariet) 20 mg b.i.d., amoxicillin (Ospamox) 1 g b.i.d. and clarithromycin (Klacid) 500 mg b.i.d. for 14 days or rabeprazole (Pariet) 20 mg q.i.d., amoxicillin (Ospamox) 1 g q.i.d. also for 14 days. Eradication was tested for by the C¹³ -UBT at least 4 weeks after the completion of therapy.

RESULTS

H pylori was eradicated in 86.2% of patients (81/94) (95% CI: 77.8-91.7) in the STT group compared with 92.8% (90/97) (95% CI: 85.9-96.5) in the HDDT group on ITT analysis. On PP analysis, H pylori was eradicated in 91.0% of patients (81/89) (95% CI: 83.3-95.4) in the STT group compared with 93.8% (90/96) (95% CI: 87.0-97.1) in the HDDT group. Side effects were few although many patients in the STT arm complained of bitter taste. The HDDT arm was well tolerated by patients.

CONCLUSIONS

The HDDT gave a high eradication rate comparable to the STT for 2 weeks and was a well-tolerated regimen for H pylori eradication.

The pharmacotherapeutic management of gastroesophageal reflux disease (GERD)

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Amoxicillin or tetracycline in bismuth-containing quadruple therapy as first-line treatment for Helicobacter pylori infection

AIM

To compare the efficacy and safety between modified quadruple- and bismuth-containing quadruple therapy as first-line eradication regimen for Helicobacter pylori infection.

METHODS

This study was a multicenter, randomized-controlled, non-inferiority trial. Subjects endoscopically diagnosed with H. pylori infection were randomly allocated to receive modified quadruple- (rabeprazole 20 mg bid, amoxicillin 1 g bid, metronidazole 500 mg tid, bismuth subcitrate 300 mg qid [elemental bismuth 480 mg]; PAMB) or bismuth-containing quadruple therapy (rabeprazole 20 mg bid, bismuth subcitrate 300 mg qid, metronidazole 500 mg tid, tetracycline 500 mg qid; PBMT) for 14 days. Rates of eradication success and adverse events were investigated. Antibiotic resistance was determined using the agar dilution and DNA sequencing of the clarithromycin resistance point mutations in the 23 S rRNA gene of H. pylori.

RESULTS

In total, 233 participants were randomized, 27 were lost to follow-up, and four violated the protocol. Both regimens showed an acceptable eradication rate in the intention-to-treat (PAMB: 87.2% vs. PBMT: 82.8%, P = .37), modified intention-to-treat (96.2% vs. 96%, P > .99), and per-protocol (96.2% vs. 96.9%, P > .99) analyses. Non-inferiority in the eradication success between PAMB and PBMT was confirmed. The amoxicillin-, metronidazole-, tetracycline-, clarithromycin-, and levofloxacin-resistance rates were 8.3, 40, 9.4, 23.5, and 42.2%, respectively. Antimicrobial resistance did not significantly affect the efficacy of either therapy. Overall compliance was 98.1%. Adverse events were not significantly different between the two therapies.

CONCLUSION

Modified quadruple therapy comprising rabeprazole, amoxicillin, metronidazole, and bismuth is an effective first-line treatment for the H. pylori infection in regions with high clarithromycin and metronidazole resistance.

Previous Helicobacter pylori infection-induced atrophic gastritis: A distinct disease entity in an understudied population without a history of eradication

Individuals with chronic atrophic gastritis who are negative for active H. pylori infection with no history of eradication therapy have been identified in clinical practice. By excluding false-negative and autoimmune gastritis cases, it can be surmised that most of these patients have experienced unintentional eradication of H. pylori after antibiotic treatment for other infectious disease, unreported successful eradication, or H. pylori that spontaneously disappeared. These patients are considered to have previous H. pylori infection-induced atrophic gastritis. In this work, we define these cases based on the following criteria: absence of previous H. pylori eradication; atrophic changes on endoscopy or histologic confirmation of glandular atrophy; negative for a current H. pylori infection diagnosed in the absence of proton-pump inhibitors or antibiotics; and absence of localized corpus atrophy, positivity for autoantibodies, or characteristic histologic findings suggestive of autoimmune gastritis. The risk of developing gastric cancer depends on the atrophic grade. The reported rate of developing gastric cancer is 0.31%-0.62% per year for successfully eradicated severely atrophic cases (pathophysiologically equal to unintentionally eradicated cases and unreported eradicated cases), and 0.53%-0.87% per year for spontaneously resolved cases due to severe atrophy. Therefore, for previous H. pylori infection-induced atrophic gastritis cases, we recommend endoscopic surveillance every 3 years for high-risk patients, including those with endoscopically severe atrophy or intestinal metaplasia. Because of the difficulty involved in the endoscopic diagnosis of gastric cancer in cases of previous infection, appropriate monitoring of the high-risk subgroup of this understudied population is especially important.

Eradication Efficacy of Modified Dual Therapy Compared with Bismuth-Containing Quadruple Therapy as a First-Line Treatment of Helicobacter pylori

OBJECTIVES

This study assessed the effectiveness, adverse events, patient adherence, and costs of modified dual therapy compared with bismuth-containing quadruple therapy for treating Helicobacter pylori infection in Chinese patients. We also sought to determine whether modified dual therapy could be used as an alternative first-line treatment for H. pylori infection.

METHODS

A total of 232 H. pylori-infected, treatment-naive patients were enrolled in this open-label, randomized controlled clinical trial. Patients were randomly allocated into 2 groups: the 14-day modified dual therapy group and the bismuth-containing quadruple therapy group. Eradication rates, drug-related adverse events, patient compliance, and drug costs were compared between the 2 groups.

RESULTS

The modified dual therapy group achieved eradication rates of 87.9%, 91.1%, and 91.1% as determined by the intention-to-treat, per-protocol, and modified intention-to-treat analyses, respectively. The eradication rates were similar compared with the bismuth-containing quadruple therapy group: 89.7%, 91.2%, and 90.4%. In addition, modified dual therapy ameliorated variations in the CYP2C19, IL-1B-511, and H. pylori VacA genotypes. There were no significant differences in the compliance rates between the 2 groups. The modified dual therapy group exhibited significantly less overall side effects compared with the bismuth-containing quadruple therapy group (P < 0.001). Furthermore, the cost of medications in the modified dual therapy was lower compared with that in the bismuth-containing quadruple therapy.

CONCLUSIONS

Modified dual therapy at high dose and administration frequency is equally effective and safer and less costly compared with bismuth-containing quadruple therapy.

Role of Vonoprazan in Helicobacter pylori Eradication Therapy in Japan

Complete eradication of Helicobacter pylori is important for preventing the development of gastric cancer. The outcome of H. pylori eradication therapy is mainly dependent on bacterial susceptibility to antimicrobial agents and potent neutralization of intragastric pH across 24 h, especially when using acid-sensitive antimicrobial agents such as clarithromycin (CLR), amoxicillin and sitafloxacin. However, conventional regimens comprising twice-daily doses (bid) of proton pump inhibitors (PPIs) are generally insufficient for maintaining the required gastric acid secretion for 24 h for successful eradication in all H. pylori-positive patients. Further, the increasing prevalence of CLR-resistant strains with each year has led to a decrease in eradication rates of first-line PPI- and CLR-containing therapies in developed countries, including Japan. In 2015, the potassium-competitive acid blocker vonoprazan (VPZ) became clinically available in Japan. VPZ competitively inhibits H⁺/K⁺-ATPase activity more potently than PPIs (e.g., omeprazole, lansoprazole, rabeprazole, pantoprazole, and esomeprazole). Therefore, a VPZ-containing H. pylori eradication regimen is expected to increase the eradication rate compared with conventional regimens containing a standard dose of PPI. In fact, a recent meta-analysis that investigated the efficacy of first-line eradication therapy showed that a VPZ-containing regimen achieved a higher eradication rate than a PPI-containing regimen. While the Maastricht V/Florence Consensus Report recommends selecting a bismuth or non-bismuth quadruple therapy and concomitant therapy for patients living in areas with high prevalence of CLR resistance, a VPZ-containing regimen demonstrates effectiveness for patients infected with CLR-resistant strains and patients living in areas where the prevalence of CLR-resistant strains is >15%. As a next step, studies are needed to determine the factors affecting the clinical outcome of VPZ-containing therapy and optimal VPZ-containing alternative regimens for tailored treatments. In this review, we summarize the advantages and disadvantages of VPZ in H. pylori eradication therapy.

Current Trends in the Management of Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) characterized by heartburn and/or regurgitation symptoms is one of the most common gastrointestinal disorders managed by gastroenterologists and primary care physicians. There has been an increase in GERD prevalence, particularly in North America and East Asia. Over the past three decades proton pump inhibitors (PPIs) have been the mainstay of medical therapy for GERD. However, recently there has been an increasing awareness amongst physicians and patients regarding the side effects of the PPI class of drugs. In addition, there has been a marked decline in the utilization of surgical fundoplication as well as a rise in the development of nonmedical therapeutic modalities for GERD. This review focuses on different management strategies for GERD, optimal management of refractory GERD with special focus on available endoluminal therapies and the future directions.

Effect of ilaprazole on the healing of endoscopic submucosal dissection-induced gastric ulcer: randomized-controlled, multicenter study

BACKGROUND

The optimal treatment regimen or the duration of treatment for an endoscopic submucosal dissection (ESD)-induced gastric ulcer has not been established. The aim of this study was to assess the efficacy of novel proton-pump inhibitor, ilaprazole, for the treatment of ESD-induced gastric ulcer.

METHODS

This was a prospective, open-label, randomized multicenter study. Between June 2015 and March 2018, a total of 176 patients (178 lesions) who underwent ESD for a gastric neoplasm were randomly allocated to receive the oral proton-pump inhibitor ilaprazole 20 mg or rabeprazole 20 mg daily for 8 weeks. The primary outcome was the ulcer healing rate at 4 and 8 weeks.

RESULTS

A total of 155 (157 lesions) and 154 patients (156 lesions) were included in the modified intention-to-treat (mITT) and per-protocol analyses, respectively. There was no significant difference in the ulcer healing rate (ilaprazole vs. rabeprazole, 97.4% vs. 97.0 p = 0.78 at 4 weeks, 100% vs. 100%, p = 0.95 at 8 weeks in the mITT analysis) or stage of ulcer (scar stage, 25.6% vs. 17.7%, p = 0.25 at 4 weeks, 92.3% vs. 88.6%, p = 0.59 at 8 weeks in the mITT analysis) between the treatment groups. The quality of ulcer healing was not significantly different between the two groups. No independent predictive factor for higher-quality ulcer healing was found in the multivariate analysis.

CONCLUSIONS

According to this trial, ilaprazole and rabeprazole showed no significant difference in the healing of artificial gastric ulcers. Most of the ulcers achieved complete healing within 4-8 weeks.

TRIAL REGISTRATION

ClinicalTrial.gov NCT02638584.

Management of Gastroesophageal Reflux Disease

Management of gastroesophageal reflux disease (GERD) commonly starts with an empiric trial of proton pump inhibitor (PPI) therapy and complementary lifestyle measures, for patients without alarm symptoms. Optimization of therapy (improving compliance and timing of PPI doses), or increasing PPI dosage to twice daily in select circumstances, can reduce persistent symptoms. Patients with continued symptoms can be evaluated with endoscopy and tests of esophageal physiology, to better determine their disease phenotype and optimize treatment. Laparoscopic fundoplication, magnetic sphincter augmentation, and endoscopic therapies can benefit patients with well-characterized GERD. Patients with functional diseases that overlap with or mimic GERD can also be treated with neuromodulators (primarily antidepressants), or psychological interventions (psychotherapy, hypnotherapy, cognitive and behavioral therapy). Future approaches to treatment of GERD include potassium-competitive acid blockers, reflux-reducing agents, bile acid binders, injection of inert substances into the esophagogastric junction, and electrical stimulation of the lower esophageal sphincter.

Four-times-daily Dosing of Rabeprazole with Sitafloxacin, High-Dose Amoxicillin, or Both for Metronidazole-Resistant Infection with Helicobacter pylori in Japan

BACKGROUND

The bacterial resistance of Helicobacter pylori to antimicrobial agents such as clarithromycin and metronidazole has been increasing worldwide, leading to the failure of eradication treatment. Here, we present an eradication regimen consisting of four-times-daily dosing (q.i.d.) of rabeprazole with potent acid inhibition.

AIM

To investigate the efficacy of eradication therapy with rabeprazole q.i.d. and amoxicillin or sitafloxacin in Japanese infected with a metronidazole-resistant strain.

METHODS

We retrospectively investigated the efficacy of eradication regimens with rabeprazole q.i.d. for 7 days in 111 Japanese pooled patients infected with a metronidazole-resistant strain of H. pylori at Hamamatsu University School of Medicine Hospital or the Shiga University of Medical Science Hospital: 1, with sitafloxacin 100 mg twice daily (b.i.d.) (n = 82); 2, with amoxicillin 500 mg q.i.d. (n = 15); and 3, with amoxicillin q.i.d. and sitafloxacin b.i.d.-combined regimen (n = 14). Eradication status was assessed at 8 weeks via a ¹³ C-urea breath test.

RESULTS

Eradication rate on intention-to-treat analysis was 93.7% (95% confidence interval: 87.4-97.4%, 104/111), irrespective of the high prevalence of strains resistant to clarithromycin (81.1%, 90/111) and levofloxacin (42.3%, 47/111). No significant differences in eradication rates were observed among the different treatment regimens (p = .408), eradication history (p = .096) and different CYP2C19 genotypes (p = .789). On multivariate analysis, no significant risk factor for eradication failure by therapy with potent acid inhibition was seen.

CONCLUSION

In Japanese patients infected with metronidazole-resistant strains of H. pylori, eradication rates exceeding 90% can be achieved using appropriate dosing of antibiotic agents with strain susceptibility (amoxicillin q.i.d. and/or sitafloxacin b.i.d.) together with acid inhibition for a full 24 h and rabeprazole 10 mg q.i.d. These findings may be further evidence for dual therapy with rabeprazole q.i.d. and an antibiotic agent (amoxicillin q.i.d. or sitafloxacin b.i.d.) in Japanese patients with metronidazole-resistant strains.

Optimized high-dose amoxicillin-proton-pump inhibitor dual therapies fail to achieve high cure rates in China

Background\Aim: Quadruple daily administration of proton-pump inhibitor (PPI) therapy achieves potent acid inhibition, and combined with amoxicillin, with its pharmacodynamic and pharmacokinetic characteristics, may be efficient for Helicobacter pylori eradication. We compared the efficacy of two optimized high-dose dual therapies with a bismuth-containing quadruple regimen for treating H. pylori infection. Rabeprazole dosages for H. pylori eradication were also evaluated.

PATIENTS AND METHODS

Treatment-naive and H. pylori-positive subjects were recruited and randomly apportioned to three treatment groups: Group A (n = 87), rabeprazole 10 mg plus amoxicillin 750 mg (4 times/day for 14 days); Group B (n = 87), rabeprazole 20 mg plus amoxicillin 750 mg (4 times/day for 14 days); and Group C (n = 89), bismuth-containing quadruple regimen consisting of rabeprazole 20 mg, bismuth 220 mg, amoxicillin 1000 mg, and clarithromycin 500 mg (2 times/day for 14 days). Four weeks after treatment discontinuation, patients were examined for H. pylori infection by 13C-urea breath test. The rates of adverse effects, compliance, and eradication were evaluated.

RESULTS

Eradication rates in groups A, B, and C were 78.1, 81.6, and 84.3%, respectively, based on intention-to-treat analysis, or 79.1, 83.5, and 86.2%, according to per-protocol analysis. Rates of adverse events and compliance of the three groups were similar.

CONCLUSION

For treating H. pylori infection, optimized high-dose amoxicillin-PPI dual therapies failed to achieve high cure rates in China and held no advantage over a bismuth-containing quadruple regimen.

The role of acid inhibition in Helicobacter pylori eradication

Infection of the stomach by the gastric pathogen Helicobacter pylori results in chronic active gastritis and leads to the development of gastric and duodenal ulcer disease and gastric adenocarcinoma. Eradication of H. pylori infection improves or resolves the associated pathology. Current treatments of H. pylori infection rely on acid suppression in combination with at least two antibiotics. The role of acid suppression in eradication therapy has been variously attributed to antibacterial activity of proton pump inhibitors directly or through inhibition of urease activity or increased stability and activity of antibiotics. Here we discuss the effect of acid suppression on enhanced replicative capacity of H. pylori to permit the bactericidal activity of growth-dependent antibiotics. The future of eradication therapy will rely on improvement of acid inhibition along with current antibiotics or the development of novel compounds targeting the organism's ability to survive in acid.

Eradication of Helicobacter pylori Infection

Helicobacter pylori infects about 50 % of the world's population, causing at a minimum chronic gastritis. A subset of infected patients will ultimately develop gastric or duodenal ulcer disease, gastric adenocarcinoma, or MALT (mucosa-associated lymphoid tissue) lymphoma. Eradication of H. pylori requires complex regimens that include acid suppression and multiple antibiotics. The efficacy of treatment using what were once considered standard regimens have declined in recent years, mainly due to widespread development of antibiotic resistance. Addition of bismuth to standard triple therapy regimens, use of alternate antibiotics, or development of alternative regimens using known therapies in novel combinations have improved treatment efficacy in specific populations, but overall success of eradication remains less than ideal. Novel regimens under investigation either in vivo or in vitro, involving increased acid suppression ideally with fewer antibiotics or development of non-antibiotic treatment targets, show promise for future therapy.

Tailored versus Triple plus Bismuth or Concomitant Therapy as Initial Helicobacter pylori Treatment: A Randomized Trial

BACKGROUND

With markedly increased antibiotic resistance and unsatisfactory efficacies of common empiric eradication regimens in the mainland of China, tailored therapy may be the best choice to achieve good efficacy. This study compared the eradication rates, safety, and compliance of tailored therapy to those of triple therapy plus bismuth and concomitant therapy in the naïve patients with Helicobacter pylori infection.

MATERIALS AND METHODS

Between September 2013 and April 2014, 1050 patients with H. pylori infection at three tertiary hospitals were randomly assigned to 10-day treatment with tailored, triple plus bismuth, or concomitant regimens. In tailored therapy, medications were adjusted according to clarithromycin sensitivity and cytochrome P450 isoenzyme 2C19 genotype. The antimicrobial susceptibility testing (E test) was performed. Eradication status was assessed 4-12 weeks after treatment.

RESULTS

The eradication rate was significantly higher in tailored group than in triple plus bismuth and concomitant groups in both intention-to-treat (88.7 vs 77.4 vs 78.3%, p < .001) and per-protocol (93.3 vs 87.0 vs 87.4%, p = .021) analyses in a setting with high antibiotic resistance (clarithromycin 48.8%, metronidazole 65.7%, and dual resistance 35.3%). Significantly, fewer adverse effects occurred in tailored group than in concomitant group (22.0 vs 31.7%, p = .018). The eradication rates of dual clarithromycin and metronidazole resistance, isolated clarithromycin resistance, isolated metronidazole resistance, and dual susceptible were 78.7, 82.4, 94.8, and 94.4% in triple therapy plus bismuth and 75.9, 87.2, 92.9, and 95.2% in concomitant therapy, respectively.

CONCLUSIONS

First-line tailored therapy achieves significantly higher eradication rates and fewer side effects, compared to triple therapy plus bismuth and concomitant therapy in a setting with high rates of clarithromycin and metronidazole resistance.

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.

Potent Gastric Acid Inhibition Over 24 Hours by 4-Times Daily Dosing of Esomeprazole 20 mg

BACKGROUND

When administered at a standard dose, proton pump inhibitors (PPIs) do not always provide sufficient acid inhibition for all subjects, particularly in extensive metabolizers (EMs) of CYP2C19. Whether esomeprazole at a dose of 20 mg four times daily dosing (q.i.d.) can attain sufficient acid inhibition throughout 24 h in EMs remains unclear. We therefore investigated the efficacy of esomeprazole q.i.d. for acid inhibition.

METHODS

In a randomized cross-over design, 30 Helicobacter pylori-negative healthy young Japanese volunteers received esomeprazole at a dose of 20 mg two times a day (b.i.d.) or q.i.d. for 7 days. A pH monitoring was conducted before the trial as a control and on day 7 of both regimens.

RESULTS

Median pH values in the q.i.d. regimen were significantly higher than those with the b.i.d. regimen in EMs (b.i.d.: 5.3, q.i.d.: 6.6, p = 0.022), intermediate metabolizer (IM) (b.i.d.: 5.5, q.i.d.: 6.8, p = 0.005) and poor metabolizer (PM) (b.i.d.: 6.2, q.i.d.: 7.0, p = 0.047), respectively. Median pH with the b.i.d. regimen differed significantly by CYP2C19 genotypes (p = 0.004), but not the q.i.d. regimen (p = 0.384).

CONCLUSION

Esomeprazole q.i.d. achieved potent acid inhibition in all Helicobacter pylori-negative subjects, irrespective of CYP2C19 genotype, which might be one of the rescue regimens for patients' refractory to PPI treatment.

Factors associated with healing of artificial ulcer after endoscopic submucosal dissection with reference to Helicobacter pylori infection, CYP2C19 genotype, and tumor location: Multicenter randomized trial

BACKGROUND AND AIM

Healing speed of peptic ulcer is affected by a number of factors, including Helicobacter pylori (H. pylori) infection and intragastric pH. Acid inhibition exerted by proton pump inhibitors differs by CYP2C19 genotype. Herein, we investigated whether healing speed of artificial ulcers formed after endoscopic submucosal dissection (ESD) was influenced by H. pylori infection, CYP2C19 genotype, or other factors.

METHODS

A total of 96 H. pylori-positive patients with gastric tumors scheduled for ESD were randomly assigned to receive eradication therapy for H. pylori before ESD (pre-ESD eradication) (n = 44) or after (post-ESD eradication) (n = 52). Patients received eradication therapy consisting of lansoprazole 30 mg, amoxicillin 750 mg, and clarithromycin 200 mg twice daily for 1 week. After ESD, lansoprazole 30 mg was given once daily for 8 weeks. Ulcer size was endoscopically measured on the next day and at 4 and 8 weeks after ESD.

RESULTS

Mean reduction rate of artificial ulcer area in the pre-ESD eradication group was 94.7% ± 5.5% at 4 weeks, which was similar to that in the post-ESD eradication group (94.7% ± 6.7%, P = 0.987), irrespective of CYP2C19 genotype. In multivariate analyses, location of gastric tumor (middle and upper, odds ratio: 4.05, 95% CI: 1.620-10.230, P = 0.003) was a factor for 97% reduction of artificial ulcer area at 4 weeks post-ESD, but CYP2C19 genotype and H. pylori infection were not.

CONCLUSION

Healing speed of ESD-induced artificial ulcer was affected by tumor location, but not by time of H. pylori eradication, resected size, or CYP2C19 genotype.

One-day front-loading with four doses of rabeprazole followed by a standard twice-daily regimen provides sufficient acid inhibition in extensive metabolizers of CYP2C19

BACKGROUND

Four times daily dosing (qid) with a proton pump inhibitor can cause rapid increase in intragastric pH. We investigated the efficacy of the front-loading with rabeprazole 10 mg qid on a subsequent regimen with rabeprazole 10 mg twice daily (bid) for 7 days in extensive metabolizers (EMs) of CYP2C19.

METHODS

Five EMs received three different 1-week regimens in a crossover manner as follows: (1) rabeprazole 10 mg bid for 7 days; (2) a front-loading regimen of rabeprazole (rabeprazole 10 mg qid on day 0 and bid on days 1 to 7); and (3) rabeprazole 10 mg qid for 7 days. Five intermediate metabolizers (IMs) and four poor metabolizers (PMs) received rabeprazole 10 mg bid regimen only. Twenty-four-hour intragastric pH-monitorings were performed on days 1, 4, and 7. Area under the intragastric pH-time curves (AUCs) from days 1 to 7 was calculated using 24-h median intragastric pHs on days 1, 4, and 7.

RESULTS

Twenty-four-hour intragastric pHs in the front-loading group on days 1, 4, and 7 were 5.1, 4.9, and 5.1, respectively. The median AUC with front-loading in EMs (34.4, pH·day) was significantly higher than that in EMs with rabeprazole 10 mg bid (30.74, p = 0.043). No statistically significant differences in median AUCs were noted among front-loading in EMs, rabeprazole 10 mg qid in EMs (37.2), rabeprazole 10 mg bid in IMs (37.3), and PMs (39.4).

CONCLUSIONS

The one-day front-loading regimen of rabeprazole 10 mg qid provided sufficient acid inhibition for 7 days, even in CYP2C19 EMs.

Colloidal bismuth subcitrate impedes proton entry into Helicobacter pylori and increases the efficacy of growth-dependent antibiotics

BACKGROUND

Successful eradication of Helicobacter pylori is becoming more difficult, mainly due to emerging antibiotic resistance. Treatment regimens containing bismuth have increased efficacy, but the mechanism is unknown. Helicobacter pylori is a neutralophile adapted to survive the acidic gastric environment via acid acclimation, but demonstrates more robust growth at neutral pH. Many antibiotics used to treat H. pylori rely on bacterial growth.

AIM

To investigate the mechanism of increased efficacy of bismuth-containing H. pylori treatment regimens.

METHODS

RNAseq and qPCR, urease activity in permeabilised and intact bacteria, internal pH and membrane potential were measured with and without colloidal bismuth subcitrate (CBS). Bacterial survival was assessed with CBS and/or ampicillin.

RESULTS

Genes involved with metabolism and growth were upregulated in the presence of CBS at acidic pH. Urease activity of permeabilised H. pylori at pH 7.4 and 4.5 decreased in the presence of CBS, but intact urease activity decreased only at acidic pH. The fall in cytoplasmic pH with external acidification was diminished by CBS. The increase in membrane potential in response to urea addition at acidic medium pH was unaffected by CBS. The impact of CBS and ampicillin on H. pylori survival was greater than either agent alone.

CONCLUSIONS

Bismuth is not acting directly on urease or the urea channel. Colloidal bismuth subcitrate impedes proton entry into the bacteria, leading to a decrease in the expected fall in cytoplasmic pH. With cytoplasmic pH remaining within range for increased metabolic activity of a neutralophile, the efficacy of growth-dependent antibiotics is augmented.

High Helicobacter pylori cure rate with sitafloxacin-based triple therapy

BACKGROUND

Bacterial resistance of Helicobacter pylori to antibiotics is increasing and it often leads to failure of antibiotic treatment. A new sitafloxacin-based triple therapy was developed to counter this situation; the fluoroquinolone sitafloxacin has a low minimum inhibitory concentration for H. pylori.

AIM

To investigate the efficacy in Japanese patients of sitafloxacin-based triple therapy and document its efficacy in relation to anti-microbial susceptibility.

METHODS

We investigated the efficacy of a 1-week sitafloxicin-based regimen of rabeprazole 10 mg four times daily (q.d.s.), metronidazole 250 mg twice daily (b.d.) and sitafloxacin 100 mg b.d. in 180 H. pylori-positive Japanese patients (first-line treatment: n = 45, second-line; n = 41, third-line: n = 94). At 8 weeks, patients were given the (13) C-urea breath test to assess eradication status.

RESULTS

Eradication rate was 92.2% [95% confidence interval (CI): 87.3-95.7%, 166/180] in intention-to-treat analysis. Although the eradication rate was higher in patients treated with first-line therapy [45/45 (100%, 95% CI: 83.4-100%)] than in those with second- [38/41 (92.7%, 80.1-98.5%)] or third-line therapy [83/94 (88.3%, 80.0-94.0%)], no significant differences were noted with respect to the number of previous therapy attempts (P = 0.054). Eradication rates in patients infected with sensitive- and resistant strains to metronidazole were 96.6% (28/29) and 96.3% (77/80) (P = 0.941), respectively, while rates were 98.4% (60/61) in sitafloxacin-sensitive and 50.0% (1/2) in sitafloxacin resistant strains (P < 0.001).

CONCLUSION

Sitofloxacin-based triple therapy with metronidazole b.d. and rabeprazole q.d.s. achieved an eradication rate exceeding 88%, irrespective of eradication history, CYP2C19 genotype, or metronidazole resistance status.

Efficacy of tailored Helicobacter pylori eradication treatment based on clarithromycin susceptibility and maintenance of acid secretion

BACKGROUND

Insufficient acid inhibition during Helicobacter pylori eradication treatment and bacterial resistance to antibiotics often causes eradication failure. Four times daily dosing (q.i.d.) of a proton-pump inhibitor (PPI) achieves potent acid inhibition, suggesting its potential usefulness as a regimen for eradicating H. pylori infection. Therefore, a tailored eradication regimen based on antibiotic susceptibility and maintenance of acid inhibition should have a high success rate. We investigated the efficacy of such treatment based on clarithromycin (CAM) susceptibility.

METHODS

Using 153 H. pylori-positive Japanese patients, we investigated the efficacy of tailored eradication strategy: (1) Patients infected with CAM-sensitive H. pylori were treated with a PPI (rabeprazole 10 mg q.i.d.), amoxicillin 500 mg q.i.d., and CAM 200 mg b.i.d. (n = 89), and (2) patients infected with CAM-resistant were given the same doses of rabeprazole and amoxicillin and metronidazole 250 mg b.i.d. (n = 64) for 1 week.

RESULTS

In the tailored regimen group, the overall eradication rate was 96.7% (95% CI: 92.5-98.9%, 148/153) in the intention-to-treat (ITT) analysis and 97.4% (93.4-99.3%, 148/152) in the PP analysis. The eradication rates for the CAM- and metronidazole-based treatments were similar (95.5% and 98.4%, respectively, p = .400). The tailored treatment achieved a high eradication rate in CYP2C19 rapid metabolizers who were a resistance genotype for PPI treatment (94.3% (86.0-98.4%, 66/70)).

DISCUSSION

A tailored H. pylori eradication regimen based on CAM susceptibility and maintaining acid secretion (rabeprazole 10 mg q.i.d.) is useful because it can achieve an eradication rate exceeding 95%, irrespective of eradication history, thus overcoming differences among CYP2C19 genotypes.

Comparison of acid inhibition with standard dosages of proton pump inhibitors in relation to CYP2C19 genotype in Japanese

INTRODUCTION

The aim of therapeutic regimens using proton pump inhibitors (PPIs) in patients with acid-related diseases is to potently inhibit acid secretion for the full 24 h. However, optimum treatment is still unclear because the pharmacodynamics of PPIs differ among CYP2C19 genotypes and most of the previous studies have had loss of sample power.

METHODS

Using pH monitoring, we compared acid inhibition at standard dosage of omeprazole (20 mg, 50 times), lansoprazole (30 mg, 68 times), and rabeprazole (10 mg, 65 times) in Helicobacter pylori-negative healthy young Japanese volunteers.

RESULTS

Median pH with rabeprazole was 5.4 (3.3-7.5), which was significantly greater than with either omeprazole [4.4 (2.1-7.3)] or lansoprazole [4.8 (3.5-6.4)] (both P < 0.05). Median 24-h pH differed among the different CYP2C19 genotypes in all three PPIs. In CYP2C19 extensive metabolizers (EMs), the genotype that is refractory to PPI treatment, median pH with omeprazole, lansoprazole, and rabeprazole was 3.8 (2.1-4.4), 4.5 (3.5-5.3) and 4.8 (3.3-7.5), respectively.

DISCUSSION

Treatment with the selected PPIs at their standard dosages had difficulty maintaining acid inhibition for a full 24 h, especially in CYP2C19 EM. However, rabeprazole has the merit of less influence of CYP2C19 genotype compared with the other PPIs.

Efficacy of tailored Helicobacter pylori eradication therapy based on antibiotic susceptibility and CYP2C19 genotype

The cure rates of Helicobacter pylori (H. pylori) eradication therapy using a proton pump inhibitor (PPI) and antimicrobial agents such as amoxicillin, clarithromycin, and metronidazole are mainly influenced by bacterial susceptibility to antimicrobial agents and the magnitude of the inhibition of acid secretion. Annual cure rates have gradually decreased because of the increased prevalence of H. pylori strains resistant to antimicrobial agents, especially to clarithromycin. Alternative regimens have therefore been developed incorporating different antimicrobial agents. Further, standard PPI therapy (twice-daily dosing) often fails to induce a long-term increase in intragastric pH > 4.0. Increasing the eradication rate requires more frequent and higher doses of PPIs. Therapeutic efficacy related to acid secretion is influenced by genetic factors such as variants of the genes encoding drug-metabolizing enzymes (e.g., cytochrome P450 2C19, CYP2C19), drug transporters (e.g., multidrug resistance protein-1; ABCB1), and inflammatory cytokines (e.g., interleukin-1β). For example, quadruple daily administration of PPI therapy potently inhibits acid secretion within 24 h, irrespective of CYP2C19 genotype. Therefore, tailored H. pylori eradication regimens that address acid secretion and employ optimal antimicrobial agents based on results of antimicrobial agent-susceptibility testing may prove effective in attaining higher eradication rates.

Treatment of Helicobacter pylori infection: current status and future concepts

Helicobacter pylori (H. pylori) infection is highly associated with the occurrence of gastrointestinal diseases, including gastric inflammation, peptic ulcer, gastric cancer, and gastric mucosa-associated lymphoid-tissue lymphoma. Although alternative therapies, including phytomedicines and probiotics, have been used to improve eradication, current treatment still relies on a combination of antimicrobial agents, such as amoxicillin, clarithromycin, metronidazole, and levofloxacin, and antisecretory agents, such as proton pump inhibitors (PPIs). A standard triple therapy consisting of a PPI and two antibiotics (clarithromycin and amoxicillin/metronidazole) is widely used as the first-line regimen for treatment of infection, but the increased resistance of H. pylori to clarithromycin and metronidazole has significantly reduced the eradication rate using this therapy and bismuth-containing therapy or 10-d sequential therapy has therefore been proposed to replace standard triple therapy. Alternatively, levofloxacin-based triple therapy can be used as rescue therapy for H. pylori infection after failure of first-line therapy. The increase in resistance to antibiotics, including levofloxacin, may limit the applicability of such regimens. However, since resistance of H. pylori to amoxicillin is generally low, an optimized high dose dual therapy consisting of a PPI and amoxicillin can be an effective first-line or rescue therapy. In addition, the concomitant use of alternative medicine has the potential to provide additive or synergistic effects against H. pylori infection, though its efficacy needs to be verified in clinical studies.

Twice-daily dosing of esomeprazole effectively inhibits acid secretion in CYP2C19 rapid metabolisers compared with twice-daily omeprazole, rabeprazole or lansoprazole

BACKGROUND

Twice-daily dosing of proton pump inhibitors (PPIs) is used to treat Helicobacter pylori or acid-related diseases, such as gastro-oesophageal reflux disease (GERD) refractory to standard dose of a PPI. Genetic polymorphisms of CYP2C19 are involved to different extents in the metabolism of four kinds of PPIs (omeprazole, lansoprazole, rabeprazole and esomeprazole) available in Japan.

AIM

To compare acid-inhibitory effects of the four PPIs dosed twice daily in relation to CYP2C19 genotype.

METHODS

We performed 24-h pH monitoring studies on Day 7 of PPI treatment for 40 Japanese H. pylori-negative volunteers [15 CYP2C19 rapid metabolisers (RMs), 15 intermediate metabolisers (IMs) and 10 poor metabolisers (PMs)] using a randomised four-way crossover design: omeprazole 20 mg, esomeprazole 20 mg, lansoprazole 30 mg and rabeprazole 10 mg twice daily.

RESULTS

Although median pH values with esomeprazole, omeprazole, lansoprazole and rabeprazole were 5.7 (3.5-7.2), 5.5 (2.4-7.2), 5.5 (3.7-7.3) and 5.2 (2.5-7.3), respectively (no statistically significant differences), CYP2C19 genotype-dependent differences were smaller for esomeprazole and rabeprazole compared with values for omeprazole and lansoprazole. In CYP2C19 RMs, the median pH with esomeprazole [5.4 (3.5-6.8)] was significantly higher than those with omeprazole [5.0 (2.4-5.9), P = 0.018], lansoprazole [4.7 (3.7-5.5), P = 0.017] or rabeprazole [4.8 (2.5-6.4), P = 0.002]. In IMs and PMs, the median pH was >5.0 independent of the PPI.

CONCLUSIONS

In intermediate and rapid metabolisers of CYP2C19, PPIs dosed twice daily could attain sufficient acid suppression, while in CYP2C19 RMs, esomeprazole 20 mg twice daily caused the strongest inhibition of the four PPIs. Therefore, esomeprazole may be effective in Japanese population when dosed twice daily.

Improved efficacy of proton pump inhibitor - amoxicillin - clarithromycin triple therapy for Helicobacter pylori eradication in low clarithromycin resistance areas or for tailored therapy

OBJECTIVE

Standard triple therapy for Helicobacter pylori eradication is no longer effective as an empiric choice in most areas. Even in low clarithromycin resistance areas, results ≥95% are infrequently achieved. This study was designed to search for a version of standard triple therapy for use low prevalence areas or as tailored therapy that is highly effective irrespective of CYP2C19 genotype.

DESIGN

Two prospective pilot single center studies were performed in Thailand. H. pylori-infected subjects were randomized to 7- or 14-day regimens using a high-dose proton pump inhibitor (PPI) triple therapy consisting of lansoprazole (60 mg) twice daily, amoxicillin 1 g twice daily, and long-acting clarithromycin MR 1 g once daily. H. pylori was defined as positive H. pylori culture; or two positive tests (rapid urease test and histology); CYP2C19 genotyping was performed. H. pylori eradication was evaluated by (13) C-UBT 4 or more weeks after treatment.

RESULTS

Hundred and ten subjects were enrolled (55 each to the 7- and 14-day regimens). Antibiotic susceptibility testing (25 strains) showed 40% metronidazole resistance but no clarithromycin resistance. CYP2C19 genotyping (64 subjects) revealed 56.3% rapid metabolizer, 29.7% intermediate metabolizer, and 14% poor metabolizer. The eradication rate with the 14-day regimen was 100% (95% CI = 93.5-100%) and 92.7% (95% CI = 82-97%) with the 7-day regimen. The difference was related to improved eradication at 14 days in rapid metabolizers (i.e. 100 vs 88.2%).

CONCLUSION

Triple therapy using a 14-day high-dose PPI and long-acting clarithromycin provided an excellent cure rate (100%) regardless of the CYP2C19 genotype.

The effects of varying acidity on Helicobacter pylori growth and the bactericidal efficacy of ampicillin

BACKGROUND

Penicillins inhibit cell wall synthesis; therefore, Helicobacter pylori must be dividing for this class of antibiotics to be effective in eradication therapy. Identifying growth responses to varying medium pH may allow design of more effective treatment regimens.

AIM

To determine the effects of acidity on bacterial growth and the bactericidal efficacy of ampicillin.

METHODS

H. pylori were incubated in dialysis chambers suspended in 1.5-L of media at various pHs with 5 mM urea, with or without ampicillin, for 4, 8 or 16 h, thus mimicking unbuffered gastric juice. Changes in gene expression, viability and survival were determined.

RESULTS

At pH 3.0, but not at pH 4.5 or 7.4, there was decreased expression of ~400 genes, including many cell envelope biosynthesis, cell division and penicillin-binding protein genes. Ampicillin was bactericidal at pH 4.5 and 7.4, but not at pH 3.0.

CONCLUSIONS

Ampicillin is bactericidal at pH 4.5 and 7.4, but not at pH 3.0, due to decreased expression of cell envelope and division genes with loss of cell division at pH 3.0. Therefore, at pH 3.0, the likely pH at the gastric surface, the bacteria are nondividing and persist with ampicillin treatment. A more effective inhibitor of acid secretion that maintains gastric pH near neutrality for 24 h/day should enhance the efficacy of amoxicillin, improving triple therapy and likely even allowing dual amoxicillin-based therapy for H. pylori eradication.