Effective regimens for the treatment of Helicobacter pylori infection

The effect of MDR1 C3435T polymorphism on the eradication rate of H. pylori infection in PPI-based triple therapy: A meta-analysis

BACKGROUND

Several studies have reported that multidrug resistance gene 1 (MDR1) C3435T polymorphism was associated with the rate of Helicobacter pylori (H. pylori) eradication in proton pump inhibitor (PPI)-based triple therapy. However, the conclusions were inconsistent. Therefore, this meta-analysis was conducted to evaluate the impact of MDR1 C3435T polymorphism on H. pylori eradication by PPI-based triple therapy.

METHODS

Seven eligible studies published up to August 2016 and including 1019 patients were identified by searching the Chinese Biomedical Literature database, Wan fang, PubMed, and the Web of Science electronic databases. Consequently, a meta-analysis was conducted with STATA software, using summary odds ratios (OR) and a 95% confidence interval (CI).

RESULTS

Overall, there was no significant difference between MDR1 C3435T polymorphism and the eradication rate of H. pylori in the entire genetic model, irrespective of the PPI used. Furthermore, in Asian populations, the TT genotype decreased H. pylori eradication (TT vs CT+CC: OR=0.411, 95% CI = 0.280-0.602, P = 0.000). In addition, a significantly low eradication rate was observed in a recessive model, in which either lansoprazole (TT vs CT+CC: OR = 0.305, 95% CI = 0.184-0.504, P = 0.000) or omeprazole (TT vs CT+CC: OR = 0.229, 95% CI = 0.069-0.763, P = 0.016) was taken, in a subanalysis of individual PPIs. In the analyses that were stratified by disease type, no significant difference was observed in the peptic ulcer group and the combined diseases subgroup.

CONCLUSION

This meta-analysis indicated that the TT genotype of the MDR1 C3435T polymorphism decreased H. pylori eradication in Asian populations and was also associated with a low cure rate of H. pylori in patients taking lansoprazole- and omeprazole-based triple therapies. However, future studies using larger sample sizes are required.

Characterization of the metabolism of benzaldehyde dimethane sulfonate (NSC 281612, DMS612)

INTRODUCTION

Benzaldehyde dimethane sulfonate (BEN, DMS612, NSC281612) is a bifunctional alkylating agent currently in clinical trials. We previously characterized the degradation products of BEN in plasma and blood. The conversion of BEN to its carboxylic acid analogue (BA) in whole blood, but not plasma, suggests that an enzyme in RBCs may be responsible for this conversion. BEN conversion to BA was observed in renal carcinoma cells and appeared to correlate with IC₅₀. To better understand the pharmacology of BEN, we aimed to evaluate the metabolism and enzymes potentially responsible for the conversion of BEN to BA.

METHODS

Human red blood cells (RBC) were used to characterize kinetics and susceptibility to enzyme-specific inhibitors. Recombinant enzymes were used to confirm metabolism of BEN to BA. Analytes were quantitated with established LC-MS/MS methods.

RESULTS

Average apparent Vmax and Km were 68 ng/mL min(-1) [10% RBC](-1) and 373 ng/mL, respectively. The conversion of BEN to BA in RBC was not inhibited by carbon monoxide, nitrogen gas, or menadione, an inhibitor of aldehyde oxidase. The conversion was inhibited by disulfiram, an inhibitor of ALDH. Of available ALDH isoforms ALDH1A1, ALDH3A1, ALDH2, and ALDH5A1, only ALDH1A1 converted BEN to BA.

CONCLUSION

The activating conversion of BEN to BA is mediated not by CYP450 enzymes or aldehyde oxidase, but by ALDH1A1. This enzyme, a potential stem cell marker, may be a candidate biomarker for clinical activity of BEN.

Comparison of 10 day bismuth quadruple therapy with high-dose metronidazole or levofloxacin for second-line Helicobacter pylori therapy: a randomized controlled trial

OBJECTIVES

This prospective study was designed to compare the efficacies of levofloxacin-containing and high-dose metronidazole-containing quadruple therapies after failure of standard triple therapies.

METHODS

A total of 150 Helicobacter pylori-infected patients were enrolled in our study and randomly assigned to levofloxacin-containing quadruple therapy (EBTL group) (40 mg of esomeprazole twice daily, 300 mg of bismuth subcitrate four times daily, 500 mg of tetracycline four times daily and 500 mg of levofloxacin once daily for 10 days) (n = 76) or high-dose metronidazole-based quadruple therapy (EBTM group) (40 mg of esomeprazole twice daily, 300 mg of bismuth subcitrate four times daily, 500 mg of tetracycline four times daily and 500 mg of metronidazole four times daily for 10 days) (n = 74). Follow-up endoscopy or urea breath test was done 16 weeks later to assess the treatment response. Patients' responses, CYP2C19 genotypes and antibiotic resistances were also examined. All participants, caregivers and those assessing the outcomes were blinded to group assignment.

RESULTS

Intention-to-treat analysis revealed that both groups showed similar eradication rates: EBTL, 78.9% (60/76) (95% CI 69.7%-88.1%) and EBTM, 79.7% (59/74) (95% CI 70.5%-88.7%) [risk ratio (RR) 0.97, 95% CI 0.44-2.14]. Per-protocol results were EBTL = 87.0% (60/69) (95% CI 79.4%-94.9%) and EBTM = 90.8% (59/65) (95% CI 83.8%-97.8%) (RR 0.68, 95% CI 0.23-2.0). We did not find significant differences in compliance (RR 0.5, 95% CI 0.54-2.3) and adverse events (RR 1.11, 95% CI 0.54-2.3) between the two groups. Logistic regression analysis showed that only compliance was an important predictor for eradication failure. CYP2C19 polymorphism did not influence the eradicating effect.

CONCLUSIONS

The 10 day bismuth quadruple therapies with high-dose metronidazole or levofloxacin were effective even in areas with high resistance. These two therapies were equally safe and tolerated. Besides this, the metronidazole-containing therapy was cheaper. So it is persuasive that high-dose metronidazole-containing quadruple therapy could be a good choice for second-line H. pylori eradication in areas with high resistance.

[Modern Helicobacter pylori therapies in times of increasing anti biotic resistance]

Recommendation for the diagnosis and treatment of Helicobacter pylori Infection are defined in recent national and international guidelines. In Germany, proton pump inhibitor-based triple therapy with clarithromycin and metronidazole or amoxicillin is still the standard in first line therapy. However, success rates have decreased substantially during the last years due to increasing antibiotic resistance, particularly in patients from Southern Europe. In addition, antimicrobial resistance rates against the standard antibiotics further increases dramatically after failure of first line therapy deeming the repeated use of these antibiotics basically impossible. Against this background, a critical appraisal and eventually adaption of therapeutic options both in first line and rescue treatment appears necessary. This paper gives an overview on the current status of therapeutic options and developments in the treatment of H. pylori infection in the light of increasing antibiotic resistance.

Rabeprazole can overcome the impact of CYP2C19 polymorphism on quadruple therapy

OBJECTIVES

The prospective study was designed to clarify the impact of CYP2C19 on quadruple therapies and survey the efficacies of rabeprazole-based quadruple therapy for Helicobacter pylori infection after failure of standard triple therapies.

PATIENTS AND METHODS

From January 2007 to March 2009, 1055 H. pylori-infected patients received standard triple regimens (proton-pump inhibitor (PPI), clarithromycin, and amoxicillin). Helicobacter pylori eradication was achieved in 865 (81.9%) subjects. One hundred ninety eradication-failure patients were enrolled and randomly assigned to receive a 7-day eradication therapy. Ninety-six patients were treated with esomeprazole-based quadruple rescue therapies (EB), while 94 patients were treated with rabeprazole-based quadruple rescue therapies (RB). Follow-up endoscopy was done 16 weeks later to assess the treatment response. Patients' responses, CYP2C19 genotypes, and antibiotics resistances were also examined.

RESULTS

Intention-to-treat analysis revealed that RB had better eradication rates than EB (EB: 72.9%; 95% CI: 64.9-80.9% and RB: 78.7%; 95% CI 72.5-84.9%) (p value = .543). Per-protocol results were EB = 75.3%; 95% CI: 70.3-80.3% and RB = 85.1%; 95% CI: 80.6-89.6% (p value = .0401). Both regimens had similar compliance (p value = 0.155) and adverse events (p value = 0.219). We also surveyed those patients without resistance of any antibiotics. RB still showed better outcome than EB. Our data showed that esomeprazole-based regimen and CYP2C19 Hom EM genotype were important predictors for eradication failure.

CONCLUSIONS

In quadruple therapy, rabeprazole-based regimens had better efficacy than esomeprazole-based regimens. CYP2C19 polymorphism also played an important role in quadruple therapy. It seems advisable to change PPI to rabeprazole in second-line quadruple therapy.

Prevalence of multidrug-resistant Helicobacter pylori in Bulgaria

The aim of this study was to evaluate the presence and prevalence of multidrug antibacterial resistance in Helicobacter pylori in Bulgaria from 2005 to 2008. The resistance in 828 untreated adults, 124 treated adults and 105 untreated children was, respectively, 26.5, 50.8 and 16.2% for metronidazole; 18.4, 45.2 and 19% for clarithromycin; 1, 2.4 and 0% for amoxicillin; 4.4, 10.6 and 1.9% for tetracycline; and 9, 14.5 and 5.8% for ciprofloxacin. Triple resistance to the evaluated agents was uncommon and was detected in 1% of the untreated children, 3.5% of the untreated adults and 13.6% of the treated adults. Five H. pylori strains were resistant to amoxicillin, metronidazole and clarithromycin, two of them exhibiting quadruple resistance. Resistance to four of the five antibacterials tested was found in 0.7% of the untreated and 1.8% of the treated adults. The overall level of multidrug resistance in the treated adults (15.4%) was higher than that in the untreated adults (4.2%, P=0.0001) and the untreated children (1%, P=0.0001). The presence of multidrug H. pylori resistance in Bulgaria could be associated with many factors, among them the slightly increasing national use of macrolides, lincosamides and streptogramins and of quinolones since 2000, the significant increase in primary H. pylori clarithromycin resistance, the high tetracycline use between 1994 and 1999, and, in individual cases, the use of azithromycin-based regimens or reuse of nitroimidazoles. In conclusion, for the first time in a European country during the last 5 years, H. pylori strains harbouring a worrying quadruple antibacterial resistance were found in treated as well as in untreated patients. H. pylori susceptibility patterns have a tendency to become unpredictable and should be monitored constantly at both national and global levels.

Antibiotic furazolidone induces CYP1A but not CYP2E1 subfamily in rat liver

Furazolidone (FZ), one of the nitrofuran fungicides, is used as a veterinary medicine in the Middle and Far Eastern countries. In this study, FZ (125 mg/kg) was administered orally to Wistar rats for 3 days. Results of the Ames test using the S-9 fraction of rats treated with FZ showed a significant increase in the number of revertant colonies. Western blot analysis of hepatic CYP isozymes induced by FZ, revealed a remarkable induction of CYP1A1 apoprotein, but CYP1A2 and CYP2E1 apoproteins were not altered. In addition, the expression of CYP1A1 mRNA level in rats treated with FZ by RT-PCR was significantly enhanced by FZ treatment. We concluded that FZ is apparently mutagenic and induces transcription of the CYP1A1 isozyme, which metabolically activates numerous promutagens, in hepatocytes.

One-week once-daily triple therapy with esomeprazole, moxifloxacin, and rifabutin for eradication of persistent Helicobacter pylori resistant to both metronidazole and clarithromycin

AIM

To investigate a 1-week once-daily triple therapy with esomeprazole, moxifloxacin, and rifabutin for rescue therapy of Helicobacter pylori infection.

METHODS

Consecutive patients (n = 103) with at least one previous treatment failure and H. pylori infection resistant to both metronidazole and clarithromycin were treated with esomeprazole 40 mg, moxifloxacin 400 mg, and rifabutin 300 mg, given once daily for 7 days. Eradication was confirmed by histology and culture. CYP2C19 status was determined by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Intention-to-treat and per-protocol eradication rates were 77.7% (68.4-85.3) and 83.3% (74.4-90.2). Five patients discontinued prematurely (4.8%). Eradication was achieved in 93.1% of poor/intermediate metabolizers and in 78.8% of homozygous extensive metabolizers (p = .14). Eradication rates in patients with one, two, three, and four or more previous failures were 78.3%, 89.6%, 68.6%, and 88.9%, respectively (p = .21). The regimen was effective in seven of nine patients who previously failed quadruple therapy. Post-treatment resistance to moxifloxacin and rifabutin was detected in two (12.5%) and five (31%) patients after treatment failure.

CONCLUSION

Once-daily triple therapy with esomeprazole, moxifloxacin, and rifabutin is a promising, safe, and convenient regimen for rescue therapy of H. pylori infection that may serve as a valuable alternative to quadruple therapy, particularly for patients with intolerance to amoxicillin.

Prevalence and evolution of Helicobacter pylori resistance to 6 antibacterial agents over 12 years and correlation between susceptibility testing methods

The aim of this study was to evaluate Helicobacter pylori antibacterial resistance in 2005 to 2007, resistance evolution since 1996 to 1999, and performance of breakpoint susceptibility testing (BST) compared with E test for clarithromycin or agar dilution method (ADM) for metronidazole, amoxicillin, tetracycline, and ciprofloxacin. Resistance in 613 untreated adults, 91 treated adults, and 75 untreated children was 25%, 48.4%, and 16% for metronidazole; 17.8%, 45.1%, and 18.7% for clarithromycin; 4.4%, 13.3%, and 2.7% for tetracycline; and 7.7%, 18.2%, and 6.8% for ciprofloxacin, respectively. Resistance to amoxicillin (0.9%) and nitrofurantoin (1.3%) was uncommon. Three strains (0.4%) exhibited triple resistance to amoxicillin, metronidazole, and clarithromycin. Primary resistance rates in adults and children were comparable. Metronidazole resistance was less common in ulcer adults than in the rest. Primary clarithromycin resistance increased significantly from 10% in 1996 to 1999 to 17.9% in 2005 to 2007. Many strains (26.4%) from treated adults showed resistance to metronidazole and clarithromycin. Category agreement between the BST and E test or ADM results was good (93.3-100%). In conclusion, the increasing clarithromycin resistance and presence of multidrug resistance are worrying. Fluoroquinolones should be used with caution for H. pylori eradication in treated patients.

Nitrofuran-based regimens for the eradication of Helicobacter pylori infection

Several aspects of Helicobacter pylori eradication have been meta-analyzed; however, nitrofuran-based therapies constitute an exception. The aim of this study was the systematic review and meta-analysis of the effect of furazolidone- and nitrofurantoin-based regimens in the eradication of infection. Studies evaluating the effects of nitrofurans on H. pylori were identified from Medline, EMBASE, the Cochrane Controlled Trials Register and congress abstracts. The studies were classified into groups based on first-, second- and third-line regimens. The pooled eradication rates and combined odd ratios of the individual studies were calculated and compared with the published meta-analysis. The factors influencing the efficiency of the regimens were also analyzed. Side-effects of nitrofuran-based regimens were also analyzed. The pooled eradication rate of primary proton pump inhibitor-based regimens containing furazolidone was 76.3% (CI 67.8-84.2). The odds ratio for furazolidone-based regimens versus standard triple therapies was 2.34 (CI 0.76-3.92). Ranitidine bismuth citrate + furazolidone-based triple regimens were equally efficient (83.5%, CI 74.0-93.0, P = 0.06 versus triple therapies). Schedules including a H(2) antagonist + furazolidone + one other antibiotic achieved pooled eradication rates of 79.9% (CI 67.8-89.9, P = 0.04). Bismuth-based triple therapies achieved 84.5% (CI 72.6-93.0, P = 0.002). Primary quadruple regimens containing furazolidone were superior to triple therapies (83.4%, CI 69.7-92.3, P = 0.01). Second-line schedules containing furazolidone obtained eradication rates of 76.1% (CI 66.4-85.0, P = 0.28 versus primary regimens). Third-line 'rescue' therapies were efficient in 65.5% of the cases (CI 56.3-75.5, P = 0.0001). Side-effects of the regimens containing furazolidone were more frequent than in standard therapies (P = 0.02). The combined odds ratio of side-effects for furazolidone-based versus standard therapies was 0.74 (CI 0.32-1.98). The duration of treatment, but not the furazolidone dose, influenced the treatment outcome. Primary triple regimens containing furazolidone are slightly less efficient than the standard primary combinations; primary quadruple regimens were more efficient than triple therapies. Furazolidone is also efficient as a component of second-line or rescue therapies.

Effect of MDR1 C3435T polymorphism on cure rates of Helicobacter pylori infection by triple therapy with lansoprazole, amoxicillin and clarithromycin in relation to CYP 2C19 genotypes and 23S rRNA genotypes of H. pylori

BACKGROUND

Polymorphism in MDR1 is associated with variation in the plasma level of a proton pump inhibitor.

AIM

To investigate whether MDR1 polymorphism is associated with eradication rates of Helicobacter pylori by a triple therapy with lansoprazole, amoxicillin and clarithromycin in relation to CYP2C19 genotype status and bacterial susceptibility to clarithromycin.

METHODS

A total of 313 patients infected with H. pylori completed the treatment with lansoprazole 30 mg b.d., clarithromycin 200 mg b.d. and amoxicillin 750 mg b.d. for 1 week. MDR1 C3435T polymorphism and CYP2C19 genotypes of patients and sensitivity of H. pylori to clarithromycin were determined.

RESULTS

Logistic regression analysis revealed that the MDR1 polymorphism as well as CYP2C19 genotypes of patients and clarithromycin-resistance of H. pylori were significantly associated with successful eradication. Eradication rates for H. pylori were 82% (83/101: 95% CI = 73-89), 81% (112/139: CI = 73-87), and 67% (44/73: CI = 48-72) in patients with the MDR1 3435 C/C, C/T and T/T genotype, respectively (P = 0.001).

CONCLUSIONS

Polymorphism of MDR1 is one of the determinants of successful eradication of H. pylori by the triple therapy with lansoprazole, amoxicillin and clarithromycin, together with CYP2C19 genotype and bacterial susceptibility to clarithromycin.

Personalized medicine for eradication of Helicobacter pylori

Regimens for eradication of Helicobacter pylori consist of a proton-pump inhibitor (PPI) and one or two antimicrobial agents, such as amoxicillin, clarithromycin or metronidazole. As the pharmacokinetics and pharmacodynamics of PPIs are affected by polymorphism of CYP2C19, doses and dosing schemes of a PPI should be optimized based on genotype status of each patient in order to yield higher eradication rates. PPIs affect the pharmacokinetics of other substrates of CYP2C19, such as warfarin and diazepam. Acid inhibition induced by a PPI also affects the pharmacokinetics of some drugs, such as itraconazole. Clarithromycin, one of the most frequently used antimicrobial agents in eradication of H. pylori, inhibits activity of CYP3A4, meaning that the pharmacokinetics of substrates of CYP3A4 are affected by clarithromycin. Therefore, clinicians must pay attention to the other drugs dosed to each of their patients. Therefore, the eradication regimen for H. pylori infection should be designed with the CYP2C19 genotype status, bacterial susceptibility to antimicrobial agents, and other drugs being taken by each patient having been taken into consideration.

Therapy of gastric mucosa associated lymphoid tissue lymphoma

Gastric mucosa associated lymphoid tissue (MALT) lymphoma has recently been incorporated into the World Health Organization (WHO) lymphoma classification, termed as extranodal marginal zone B-cell lymphoma of MALT-type. In about 90% of cases this lymphoma is associated with H pylori infection which has been clearly shown to play a causative role in lymphomagenesis. Although much knowledge has been gained in defining the clinical features, natural history, pathology, and molecular genetics of the disease in the last decade, the optimal treatment approach for gastric MALT lymphomas, especially locally advanced cases, is still evolving. In this review we focus on data for the therapeutic, stage dependent management of gastric MALT lymphoma. Hence, the role of eradication therapy, surgery, chemotherapy and radiotherapy is critically analyzed. Based on these data, we suggest a therapeutic algorithm that might help to better stratify patients for optimal treatment success.

Therapy of gastric mucosa-associated lymphoid tissue lymphoma

Mucosa-associated lymphoid tissue (MALT) lymphoma is a relatively common lymphoma and comprises approximately 7% of all newly diagnosed non-Hodgkin's lymphoma. It is mainly located in the stomach and has become a focus of interest due to its unique pathophysiological link with Helicobacter pylori (HP) and the consecutive response to HP eradication therapy. In view of this, HP eradication has become standard treatment for patients with localised disease, and recent data have suggested that HP-negative patients might benefit from antibiotic treatment. In case of non-response, however, the standard approach in such patients is unclear. Both radiation and chemotherapy have shown promising results, and at present there is only one randomised study, which nevertheless suggests chemotherapy as management of choice. The objective of this review is, therefore, to summarise and evaluate the data available for treatment of gastric MALT lymphoma and to highlight potential focus for further research.

The treatment ofHelicobacterpyloriinfection: the changing picture of a still unresolved problem

More than 20 years from the discovery of Helicobacter pylori there is still a need to eradicate the bacterium. The efficacy of the current preferred first-line therapy--the triple regimen--has progressively decreased over the last 5 - 6 years, paralleling the progressive increase in the prevalence of resistant bacterial strains. Similarly, the quadruple therapy has progressively lost its importance as rescue therapy in some countries where bismuth is no longer available. A large number of studies investigating new combinations of drugs, new antibiotics and new regimens have been published in recent years. The most promising regimens--sequential therapy and triple therapy with lovofloxacin--have progressively gained importance but still need further confirmation of their efficacy before they can replace the old protocols in the everyday treatment of H. pylori infection.