Efficacy of a Low-Dose Omeprazole-Based Triple-Therapy Regimen for Helicobacter pylori Eradication Independent of Cytochrome P450 Genotype

Association between failed eradication of 7-day triple therapy for Helicobacter pylori and untreated dental caries in Japanese adults

Helicobacter pylori (H. pylori) infection is a cause of gastric disorders and is treated mainly by pharmacotherapy with antimicrobial agents. An association has been reported between dental caries and H. pylori infection. As antimicrobial agents are less effective inside dental caries because of impaired blood circulation, the presence of untreated dental caries (decayed teeth) may influence the success of H. pylori eradication treatment. In this cross-sectional study, we examined whether failed eradication of H. pylori was associated with decayed teeth in Japanese adults. Enrolled were 226 participants who received dental checkups among those treated for eradication of H. pylori at Asahi University Hospital between April 2019 and March 2021. Treatment efficacy was assessed by urea breath test. Eradication failed in 38 participants (17%), decayed teeth in 32 participants (14%), and number of 0.34 teeth per participants. Multivariate logistic regression analyses showed that failed eradication of H. pylori was associated with decayed teeth (presence: odds ratio, 2.672; 95% confidence interval, 1.093-6.531) after adjusting for gender, age, and brushing frequency. These results indicate that failed eradication of H. pylori was associated with decayed teeth and suggest that untreated dental caries may impact treatment for eradication of H. pylori.

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.

Clinical management of Helicobacter pylori--the Japanese perspective

BACKGROUND

After the approval of health insurance coverage of eradication therapy for Helicobacter pylori-positive peptic ulcer disease (PUD) in 2000, comprehensive coverage for H. pylori infection itself was implemented in 2013.

METHODS

We did a literature search using PubMed database on the management of H. pylori infection including indications, regimens, outcomes of current eradication therapies, trends of antibiotic resistance rates and proposed third-line rescue therapy in Japan. We also collected data on changes of eradication rates in our hospital by searching electronic medical records.

RESULTS

After implementation of insurance coverage of eradication therapy for PUD, dramatic reduction of the number patients with PUD as well as spending on ulcer drug was documented. According to the current regulation, proton pump inhibitor (PPI)-based triple therapy with 2 antibiotics, amoxicillin (AMPC) plus clarithromycin, for 7 days is approved as the first-line therapy. After failure of the first-line therapy, PPI plus AMPC and metronidazole is authorized as the second line, which maintains an excellent eradication rate of over 90% in Japan. When these two therapies fail, a sitafloxacin-based therapy seems to be most promising among many rescue regimens.

CONCLUSION

Comprehensive public health insurance coverage of H. pylori infection will promote eradication in Japanese people infected with H. pylori, whose risk of developing gastric cancer has been shown to be high. It also provides us a unique opportunity to study whether the broader indications can accelerate the reduction of gastric cancer in Japan in the same way we witnessed the reduction of PUD.

A large-scale nationwide multicenter prospective observational study of triple therapy using rabeprazole, amoxicillin, and clarithromycin for Helicobacter pylori eradication in Japan

BACKGROUND

In recent years in Japan, the rate of clarithromycin (CAM) resistance in Helicobacter pylori has risen to around 30%, and the eradication rate with triple therapy [proton pump inhibitor + amoxicillin (AMPC) + CAM] has been trending downward to around 70%. In 2007, rabeprazole (RPZ)-based triple therapy (RPZ + AMPC + CAM: RAC therapy) was approved in Japan, and a large-scale nationwide study was therefore initiated to evaluate the efficacy and safety of RAC therapy in clinical practice.

METHODS

Patients with H. pylori-positive gastric/duodenal ulcer (including ulcer scars) were administered triple therapy comprising RPZ 10 mg, AMPC 750 mg, and CAM 200 mg (or 400 mg), twice daily for 7 days.

RESULTS

The eradication rate was 80.7% (2,551/3,162). The results of multivariate analysis indicated the following as factors affecting the eradication rate: sex, treatment compliance, history of H. pylori treatment, presence of urologic disease, presence of respiratory disease, and year of starting treatment. The incidence of adverse drug reactions (such as diarrhea and dysgeusia) was 4.4% (166/3,789). The results of multivariate analysis indicated the following as factors affecting the incidence of adverse drug reactions: sex, daily CAM dose, and history of allergies.

CONCLUSION

In a large-scale nationwide study of use in clinical practice, RAC therapy was confirmed to be effective and safe.

A randomized trial of standard-dose versus half-dose rabeprazole, clarithromycin, and amoxicillin in the treatment of Helicobacter pylori infection

OBJECTIVES

To evaluate the efficacy and safety of a standard-dose versus half-dose 10-day triple regimen for the eradication of Helicobacter pylori infection.

METHODS

A total of 115 consecutive patients with documented infection were enrolled in this open-label trial. Group A (standard dose) received rabeprazole (20 mg), amoxicillin (1 g), and clarithromycin (500 mg), all twice daily for 10 days. Group B (half dose) received rabeprazole (10 mg), amoxicillin (500 mg), and clarithromycin (250 mg), all twice daily for 10 days. (14)C urea breath tests were performed a minimum of 4 weeks after treatment and a minimum of 2 weeks off any acid-suppressive therapy. Compliance and adverse effects were evaluated throughout the treatment period.

RESULTS

A total of 115 patients were enrolled (59 women and 56 men; mean age 47.1±14.0 years). Eradication occurred in 45 of 58 patients [77.6%; 95% confidence interval (CI): 66.9-88.3%] in the standard-dose group versus 44 of 57 in the half-dose group (77.2%; 95% CI: 66.3-88.1%) on an intent-to-treat (ITT) analysis (P=1.00). Per protocol eradication rates were 45 of 57 (78.9%; 95% CI: 68.4-85.9%) and 44 of 54 (81.5%; 95% CI: 71.1-91.8%), respectively (P=0.81). The number of patients reporting any adverse effect was significantly higher in the standard-dose group (64.9 vs. 40.4%; P=0.014). The cost of treatment was significantly less in patients receiving the half-dose regimen (ITT analysis; P<0.05). The number needed to harm to suffer one additional failure in the half-dose over the standard-dose arm was 250 (ITT analysis).

CONCLUSION

A half-dose 10-day regimen of rabeprazole, amoxicillin, and clarithromycin is equally effective but cheaper and better tolerated than its standard-dose regimen in the treatment of Helicobacter pylori. Eradication rates of both regimens are, however, suboptimal compared with accepted standards.

Guidelines for the management of Helicobacter pylori infection in Japan: 2009 revised edition

BACKGROUND

Over the past few years, the profile of Helicobacter pylori infection has changed in Japan. In particular, the relationship between H. pylori and gastric cancer has been demonstrated more clearly. Accordingly, the committee of the Japanese Society for Helicobacter Research has revised the guidelines for diagnosis and treatment of H. pylori infection in Japan.

MATERIALS AND METHODS

Four meetings of guidelines preparation committee were held from July 2007 to December 2008. In the new guidelines, recommendations for treatment have been classified into five grades according to the Minds Recommendation Grades, while the level of evidence has been classified into six grades. The Japanese national health insurance system was not taken into consideration when preparing these guidelines.

RESULTS

Helicobacter pylori eradication therapy achieved a Grade A recommendation, being useful for the treatment of gastric or duodenal ulcer, for the treatment and prevention of H. pylori-associated diseases such as gastric cancer, and for inhibiting the spread of H. pylori infection. Levels of evidence were determined for each disease associated with H. pylori infection. For the diagnosis of H. pylori infection, measurement of H. pylori antigen in the feces was added to the tests not requiring biopsy. One week of proton-pump inhibitor-based triple therapy (including amoxicillin and metronidazole) was recommended as second-line therapy after failure of first-line eradication therapy.

CONCLUSION

The revised Japanese guidelines for H. pylori are based on scientific evidence and avoid the administrative restraints that applied to earlier versions.

PhRMA white paper on ADME pharmacogenomics

Pharmacogenomic (PGx) research on the absorption, distribution, metabolism, and excretion (ADME) properties of drugs has begun to have impact for both drug development and utilization. To provide a cross-industry perspective on the utility of ADME PGx, the Pharmaceutical Research and Manufacturers of America (PhRMA) conducted a survey of major pharmaceutical companies on their PGx practices and applications during 2003-2005. This white paper summarizes and interprets the results of the survey, highlights the contributions and applications of PGx by industrial scientists as reflected by original research publications, and discusses changes in drug labels that improve drug utilization by inclusion of PGx information. In addition, the paper includes a brief review on the clinically relevant genetic variants of drug-metabolizing enzymes and transporters most relevant to the pharmaceutical industry.

Rabeprazole-based eradication therapy for Helicobacter pylori: a large-scale study in Japan

BACKGROUND

Large-scale studies of rabeprazole-based Helicobacter pylori eradication therapy have not been reported in Japan.

AIMS

To evaluate H. pylori eradication by rabeprazole-based therapy with reference to antibiotic susceptibility, CYP2C19 genotype, and rabeprazole and clarithromycin dosages.

METHODS

From 35 centres 479 H. pylori-positive patients with gastric or duodenal ulcer were randomized to four treatment groups: Group 1 (10 mg rabeprazole + 750 mg amoxicillin + 200 mg clarithromycin twice daily for 7 days); Group 2 (10 mg, 750 mg, 400 mg); Group 3 (20 mg, 750 mg, 200 mg) and Group 4 (20 mg, 750 mg, 400 mg).

RESULTS

Eradication rates were 86% (102 of 119), 89% (97 of 109), 91% (106 of 116) and 90% (104 of 115) for Groups 1-4, respectively. The eradication rate was 95% (360 of 379) for clarithromycin-susceptible strains, and 50% (30 of 60) for clarithromycin-resistant strains. The eradication rates were 88% (332 of 379) and 96% (77 of 80) in extensive metabolizers and poor metabolizers, respectively.

CONCLUSIONS

Rabeprazole-based therapies achieved 50% eradication of clarithromycin-resistant H. pylori, and even achieved good rates in extensive metabolizers. Accordingly, rabeprazole can be recommended as part of a first-line proton pump inhibitor-based triple therapy for H. pylori.

Efficacy and safety of Helicobacter pylori eradication therapy with omeprazole, amoxicillin and high- and low-dose clarithromycin in Japanese patients: a randomised, double-blind, multicentre study

OBJECTIVE

Seven-day administration of omeprazole 40 mg/day + amoxicillin 1500 mg/day + clarithromycin 800 mg/day is currently approved in Japan for the eradication of Helicobacter pylori infection. We investigated the efficacy and safety of an omeprazole-based triple therapy regimen in combination with amoxicillin and low-dose clarithromycin in Japanese patients.

METHODS

Patients were randomly assigned to either the low-dose group (omeprazole 40 mg/day + amoxicillin 1500 mg/day + clarithromycin 400 mg/day) or the high-dose group (omeprazole 40 mg/day + amoxicillin 1500 mg/day + clarithromycin 800 mg/day). A total of 288 patients were allocated to the low-dose (143) and high-dose (145) groups and were treated twice daily for 1 week.

RESULTS

For the full-analysis set, H. pylori eradication rates were 81.1% (116/143 patients, 90% confidence interval [CI] 74.9, 86.3) in the low-dose group and 80.0% (116/145 patients, 90% CI 73.7, 85.3) in the high-dose group. Per-protocol eradication rates were 81.7% (103/126 patients, 90% CI 75.1, 87.2) and 84.1% (90/107 patients, 90% CI 77.1, 89.6), respectively. When patients with non-susceptibility to clarithromycin were excluded, eradication rates were >80% for both gastric and duodenal ulcers in the two groups. The results suggested that eradication rates were affected more by susceptibility to clarithromycin than to amoxicillin. Both regimens were well tolerated.

CONCLUSION

This study demonstrated that an omeprazole-based triple-therapy regimen with clarithromycin 400 mg/day was as effective as that with clarithromycin 800 mg/day for H. pylori eradication.

Challenges and opportunities of pharmacogenetics in drug development

Drugs fail the regulatory process for a variety of reasons, including issues with pharmacokinetics, safety and efficacy. One of the most exciting questions in drug development today is how far the science of pharmacogenetics, the study of the genetics of drug response, can be used to address the fundamental issues that the pharmaceutical industry is facing. In particular, the question of how far it is possible to use this emerging science to deliver the right treatment, to the right patient, at the right dose, at the right time is both the challenge and opportunity of using pharmacogenetics in drug development. This review will address these questions with several real-life examples.