A systematic comparison of triple therapies for treatment of Helicobacter pylori infection with proton pump inhibitor/ ranitidine bismuth citrate plus clarithromycin and either amoxicillin or a nitroimidazole

Helicobacter pylori infection: anything new should we know?

Over the past year, 2003-4, there have been a number of studies consolidating previous work in relation to pathogenesis of disease, diagnosis and management of Helicobacter pylori. Studies into the pathogenesis of disease have identified the main adhesin of H. pylori as an important virulence marker and as a potential target for therapy. Molecular investigations of both the strain and host variations have identified the action of several of the virulence factors, e.g. cagA, vacA, on disrupting host cell signalling and the consequences in respect of the release of chemokines from the damaged gastric epithelium and the effect on apoptosis. Over the past year, there have been further diagnostic kits developed based on modifications of current technology. Two promising areas of research for diagnosis are the use of host/strain genome polymorphisms as a means of identifying high-risk patients who may develop severe disease and the use of proteomics to identify potential antigens of diagnostic (or therapeutic) use. The three main antibiotics that are used in first-line eradication regimens are clarithromycin, metronidazole and amoxycillin. Of these, metronidazole has the highest prevalence of resistance, followed by clarithromycin; amoxycillin resistance is only rarely reported. The decreasing success of current first-line therapy is the driving force for the development of new antibiotic combinations and a search for novel sources for chemotherapeutic agents and novel therapeutic targets.

The prolongation of triple therapy for Helicobacter pylori does not allow reaching therapeutic outcome of sequential scheme: a prospective, randomised study

BACKGROUND AND AIM

One-week triple therapy for Helicobacter pylori revealed, during these last few years, a decrease in the eradication rate, so that the prolongation of its duration has been proposed. A sequential scheme recently showed very satisfactory results. We performed a prospective randomised study with the aim of either evaluating whether the triple therapy prolongation may improve its effectiveness and comparing its outcome with that of sequential regimen.

PATIENTS AND METHODS

Three hundred and forty-two H. pylori positive patients completed the study. They were randomised to receive one of the following treatments: (i) a 7-day triple therapy comprising of rabeprazole (20 mg, b.i.d.) plus clarithromycin (500 mg, b.i.d.) and amoxycillin (1 g, b.i.d.); (ii) a 10-day triple therapy comprising the same scheme; (iii) a 10-day sequential regimen comprising of rabeprazole (20 mg, b.i.d.) plus amoxycillin (1 g, b.i.d.) for 5 days followed by rabeprazole (20 mg, b.i.d.) plus clarithromycin (500 mg, b.i.d.) and tinidazole (500 mg, b.i.d.) for the next 5 days. Therapeutic results were expressed using both intention-to-treat and per protocol analyses with 95% confidence intervals. A model of multivariate logistic regression analysis was performed using therapeutic outcome as a dependent variable and including endoscopic finding, smoking habit, age and sex as candidates for the model.

RESULTS

Sequential regimen showed a significant gain in the eradication rate as compared to the 7-day (P < 0.0001) and the 10-day (P < 0.01) triple therapies, respectively. Overall eradication was lower in smokers than in non-smokers, but the difference remained significant only in the 7-day triple therapy (P < 0.01). Additionally, the overall eradication was higher in peptic ulcer than dyspepsia (P < 0.01), even if this difference was significant only for both triple therapies.

CONCLUSIONS

Seven-day triple therapy achieves disappointing eradication rates in dyspeptics and smokers. Prolonging triple therapy to 10 days does not significantly improve the eradication rate. The novel 10-day sequential regimen is more effective and equally tolerated than the 10-day triple therapy.

Effectiveness and pharmaceutical cost of sequential treatment for Helicobacter pylori in patients with non-ulcer dyspepsia

BACKGROUND

A novel 10-day sequential treatment regimen recently achieved a significantly higher eradication rate than standard 7-day therapy in both peptic ulcer disease and non-ulcer dyspepsia. Its higher performance has recently been confirmed using a halved clarithromycin dose in peptic ulcer disease.

AIMS

To evaluate whether an acceptable eradication rate could also be obtained by halving the clarithromycin dose in dyspeptic patients and to assess the role of possible factors affecting the outcome of therapy.

METHODS

In a prospective, open-label study, 162 patients with non-ulcer dyspepsia and Helicobacter pylori infection, assessed by rapid urease test and histology, were enrolled. Patients were randomized to receive either 10-day sequential therapy, comprising rabeprazole 20 mg b.d. plus amoxicillin 1 g b.d. for the first 5 days, followed by rabeprazole 20 mg b.d., clarithromycin 250 mg b.d. and tinidazole 500 mg b.d. for the remaining 5 days (low-dose therapy), or a similar schedule with clarithromycin 500 mg b.d. (high-dose therapy). Four to six weeks after therapy, H. pylori eradication was assessed by endoscopy/histology.

RESULTS

A similar H. pylori eradication rate was observed following low- and high-dose regimens for both per protocol (94% vs. 95%; P = N.S.) and intention-to-treat (93% vs. 94%; P = N.S.) analyses. No major side-effects were reported. Halving the clarithromycin dose leads to a per patient saving in pharmaceutical costs of 24.6 euros. None of the variables examined affected the effectiveness of eradication of the sequential regimen.

CONCLUSION

A reduction of the clarithromycin dose does not affect H. pylori eradication with the sequential regimen in non-ulcer dyspepsia and affords lower costs.

Best cut-off values for [14C]-urea breath tests for Helicobacter pylori detection

BACKGROUND

The 'test and treat' strategy for Helicobacter pylori is recommended in dyspeptic patients under 55 years of age with no alarm symptoms. Reliable non-invasive tests are therefore needed. The aim of this study was to assess the pre- and post-treatment accuracy of a low dose (1 microCi [37kBq]), short collecting time [14C]-UBT (urea breath test) in diagnosing H pylori infection, examining different methods to analyse the best cut-off points.

METHODS

The study included 119 patients. Endoscopy and [14C]-UBT were performed in the pre- and post-treatment setting. [14C]-UBT results were expressed in three different ways: 1) the measured disintegrations per minute (dpm) at sample time, 2) the difference (D) in dpm between sample time and the dpm at T0, 3) the ratio of dpm at sample time to dpm at T0.

RESULTS

Seventy-six out of the 119 patients (63.9%; 95% CI: 54.9 to 71.9) were infected. Seventy-three (96%) patients completed the follow-up. The most accurate results in both pre- (sensitivity 95.9%; specificity 97.7%) and post-treatment (sensitivity 90.9%; specificity 100%) were obtained using the difference (D) in dpm between sample time at T0 and at T12.5.

CONCLUSION

A low dose [14C]-UBT, with a short collecting time, is a reliable method to evaluate H. pylori infection in both the pre- and post-treatment setting.

Susceptibility of Helicobacter pylori to metronidazole

OBJECTIVES

The reliability of the Epsilometer-test (E-Test) and the disk diffusion (DD) method in the assessment of susceptibility of Helicobacter pylori (H. pylori) to metronidazole has recently been questioned, with possible clinical implications for the management of patients undergoing H. pylori eradication. The aims of this study were: 1) to compare the E-Test and disk diffusion methods to the agar dilution method for determining the susceptibility of H. pylori to metronidazole; and 2) to investigate whether potential discrepancies could be caused by the simultaneous presence of metronidazole susceptible and metronidazole resistant bacterial subpopulations.

METHODS

A total of 109 H. pylori strains from 121 consecutive patients were examined. All tests were carried out at the same time starting from primary plates. Agar dilution was performed according to National Committee for Clinical Laboratory Standard (NCCLS) standards, the E-Test according to the manufacturer's guidelines, and disk diffusion according to standard procedure using 5-mug metronidazole disks. Isolates were considered to be metronidazole resistant if the minimal inhibitory concentration was >8 mug/ml for the agar dilution and the E-Test, or if the inhibition zone around the disk was <20 mm for disk diffusion. Of 109 isolates, 43 were also investigated to detect mixed infection. Quantities of 100 mul of bacterial suspensions of each strain were seeded onto plain agar plates and plates containing 8 mug/ml of metronidazole. Cultures were considered to be mixed if the number of colonies on agar plates exceeded by at least 30% those on the metronidazole plates.

RESULTS

According to agar dilution, 57 strains (52.3%, 95% CI = 43-61.4) were metronidazole resistant. E-Test misdiagnosed two strains that were considered sensitive to metronidazole, but according to the agar dilution test they were resistant. Disk diffusion misdiagnosed three strains. Two of these strains (the same as the E-Test) were sensitive, but according to agar dilution they were metronidazole resistant; the third strain was resistant, but according to agar dilution it was sensitive. The percentages of discordance were 1.9 (95% CI = 0.5-6.6) and 2.8 (95% CI = 0.9-7.8), respectively, when the E-Test and disk diffusion were compared to agar dilution. Intertest variability among agar dilution and the E-Test showed that 39.4% (95% CI = 30.8-48.8) of minimal inhibitory concentrations were equivalent (within +/-1 log(2)), 60.6% (95% CI = 51.2-69.2) were major errors (more than +/-1 log(2)), and 3% (95% CI = 0.8-10.4) were very major errors (change in susceptibility pattern). Mixed infection was found in six of the 43 cases examined (13.9%). In four cases, metronidazole resistant strains were 1 log(10) less numerous than those that were metronidazole susceptible. In the remaining two cases, the metronidazole resistant strains were 2-3 log(10) less numerous, which caused the two misdiagnoses.

CONCLUSIONS

The E-Test and disk diffusion method are very good alternatives to agar dilution. Mixed infections are a possible cause of the discrepancies between these tests and the reference method.

Sequential treatment for Helicobacter pylori eradication in duodenal ulcer patients: improving the cost of pharmacotherapy

BACKGROUND

Several studies have shown that Helicobacter pylori eradication rates with standard 7-day triple therapy are unsatisfactory. A novel 10-day sequential treatment regimen recently achieved a significantly higher eradication rate. To improve the pharmacotherapeutic cost, we evaluated whether an acceptable eradication rate could be achieved in peptic ulcer patients by halving the dose of clarithromycin.

METHODS

In a prospective, open-label study, 152 duodenal ulcer patients with H. pylori infection, assessed by rapid urease test and histology, were enrolled. Patients were randomized to receive either a 10-day sequential treatment comprising rabeprazole 20 mg b.d. plus amoxicillin 1 g b.d. for the first 5 days, followed by rabeprazole 20 mg b.d., clarithromycin 500 mg b.d. and tinidazole 500 mg b.d. for the remaining 5 days (high-dose therapy), or a similar schedule with the clarithromycin doses halved to 250 mg b.d. (low-dose therapy). No further antisecretory drugs were offered. Four to six weeks after therapy, H. pylori eradication and ulcer healing rates were assessed by endoscopy.

RESULTS

Similar H. pylori eradication rates were observed following high- and low-dose regimens for both per protocol (97.3% vs. 95.9%; P = N.S.) and intention-to-treat (94.7% vs. 92.2%; P = N.S.) analyses. No major side-effects were reported. At repeat endoscopy, peptic ulcer healing was observed in 93% and 93% of patients following high- and low-dose therapy, respectively.

CONCLUSION

The cheaper low-dose sequential regimen may be suggested for H. pylori eradication in duodenal ulcer patients, even without continued proton pump inhibitor therapy after eradication treatment.

The clinical role of cytochrome p450 genotypes in Helicobacter pylori management

OBJECTIVE

The aim of this pharmacogenomics study was to investigate the influence of different cytochrome P450 (CYP) genotypes in Helicobacter pylori eradication therapy.

METHOD

The study involved 143 consecutive Italian Caucasian patients with H. pylori infection diagnosed and treated with 1-wk triple therapy according to European Helicobacter Pylori Study Group guidelines. Using human genomic DNA, CYP2C19 (*2 and *3) and CYP3A4 alleles (*1B, *2, and *3) were evaluated by polymerase chain reaction-restriction fragment length polymorphism assays and confirmed by sequencing the amplicons.

RESULT

According to the endoscopy-based gold standard, 93 patients achieved H. pylori eradication. Regarding CYP2C19 genotype, the 50 patients who remained infected were all homozygous or heterozygous extensive metabolizers (homEM or hetEM). Carriers of homEM fared significantly less well than those of hetEM; homEM genotype was also predictive of failure at univariate/multivariate analysis. Carriers of CYP3A4 polymorphisms achieved favorable eradication rates similar to patients bearing CYP2C19. All four patients with single CYP3A4*2 polymorphism achieved eradication, and only 29% (5/17) of all CYP3A4*1B carriers did not achieve eradication. All nine patients carrying CYP3A4 polymorphisms in the CYP2C19 hetEM subgroup were cured, suggesting the possibility of a positive synergism between CYP3A4 and CYP2C19.

CONCLUSIONS

This first pharmacogenomics study on the influence of different CYP genotypes on H. pylori therapy suggests that, as in Asian populations, CYP2C19 genotype patterns are probably also relevant in Caucasians receiving H. pylori eradication regimens that include omeprazole. The possibility of a favorable drug interaction mediated by CYP2C19 and CYP3A4 requires investigation.

High eradication rates of Helicobacter pylori with a new sequential treatment

BACKGROUND

Eradication rates of Helicobacter pylori with standard triple therapy are disappointing, and studies from several countries confirm this poor performance.

AIM

To assess the eradication rate of a new sequential treatment regimen compared with conventional triple therapy for the eradication of H. pylori infection.

METHODS

One thousand and forty-nine dyspeptic patients were studied prospectively. H. pylori-infected patients were randomized to receive 10-day sequential therapy [rabeprazole (40 mg daily) plus amoxicillin (1 g twice daily) for the first 5 days, followed by rabeprazole (20 mg), clarithromycin (500 mg) and tinidazole (500 mg) twice daily for the remaining 5 days] or standard 7-day therapy [corrected] [rabeprazole (20 mg), clarithromycin (500 mg) and amoxicillin (1 g) twice daily]. H. pylori status was assessed by histology, rapid urease test and 13C-urea breath test at baseline and 6 weeks or more after completion of treatment.

RESULTS

Higher eradication rates were found with the sequential regimen compared to the standard regimen (intention-to-treat: 92% vs. 74%, P < 0.0001; per protocol: 95% vs. 77%, P < 0.0001). Higher eradication rates were also seen in patients with peptic ulcer disease and non-ulcer dyspepsia. In both treatments, compliance was similar (> 90%), as was the rate of side-effects, which were mild.

CONCLUSIONS

This 10-day sequential treatment regimen achieves high eradication rates in peptic ulcer disease and non-ulcer dyspepsia.

Helicobacter pylori strains and histologically-related lesions affect the outcome of triple eradication therapy: a study from southern Italy

BACKGROUND

Certain evidence suggests that Helicobacter pylori strains expressing genes for cytotoxin production show a higher sensitivity than non-cytotoxic organisms to eradication treatment. No data are available on the involvement of bacterium-related lesions in different therapeutic outcomes.

AIMS

(i) To investigate whether differences in eradication rates may be related to the different expression of virulent strains (cagA, vacA, iceA) in patients undergoing proton pump inhibitor-based triple therapy, and (ii) to evaluate whether therapeutic outcome may be affected by bacterium-induced gastric lesions.

METHODS

One hundred and ten H. pylori-positive subjects were enrolled. H. pylori was genotyped by polymerase chain reaction. Treatment consisted of lansoprazole-amoxicillin-clarithromycin, twice daily for 1 week. Eradication was checked by urea breath test.

RESULTS

The eradication rate was 70%, and the absence of cagA was associated with unsuccessful treatment. No difference between the groups with successful and unsuccessful eradication was found with regard to vacA and iceA. Lympho-epithelial lesions and fibrosis were associated with unsuccessful treatment.

CONCLUSIONS

The present data confirm the importance of cagA (but not vacA and iceA) as a predictor of successful eradication. When fibrosis and lympho-epithelial lesions are present, therapy appears to be less effective. Therefore, these histological features may be involved in an unsuccessful therapeutic outcome.

Helicobacter pylori: the challenge in therapy

For the therapeutic management of Helicobacter pylori infection, the Maastricht 2-2000 Consensus Report have introduced the concept of the 'treatment package' that considers first- and second-line eradication therapies together. According to this consensus statement, the first-line therapy for H. pylori eradication is a combination of the proton pump inhibitors (PPI) or ranitidine bismuth citrate (RBC) and claritromycin plus either amoxicillin or metronidazole. The second-line treatment is suggested to be PPI-quadruple therapy for a minimum of 7 days. If bismuth compounds are not available, PPI-based triple therapy will have to be used as a second-line treatment only after susceptibility testing. Since no considerable progress has been made during the past year in treatment regimens, there is still a need for new compounds that are specific for H. pylori, which could constitute future therapies.

Alternative and rescue treatment regimens for Helicobacter pylori eradication

Eradication therapy has been incorporated into clinical practice. The regimens currently recommended for first-line treatment include a 2-week bismuth-based triple therapy (mainly in developing countries), a 1 - 2 week proton pump inhibitor (PPI)-based triple therapy and a 1-week ranitidine bismuth citrate (RBC)-based triple therapy. However, these regimens fail to eradicate Helicobacter pylori in up to 20% of patients due to poor compliance, inadequate treatment duration, smoking, old age and bacterial resistance to nitroimidazoles and/or macrolides in particular. Therefore, alternative regimens that avoid nitroimidazoles and/or macrolides or overcome bacterial resistance to these drugs, improve compliance, minimise side effects and/or reduce costs have been evaluated. One-week quadruple therapy, which adds a PPI or histamine receptor 2-blocker to bismuth-based triple therapy, usually achieves an eradication rate of 90% when used as an alternative first-line therapy but the efficacy decreases when used as a rescue therapy. Several new triple therapies that may be used as alternative and/or rescue therapies have been evaluated. Among these are furazolidone-based (furazolidone plus an antibiotic and a bismuth salt, a PPI or RBC), fluoroquinolone-based (levofloxacin or moxifloxacin plus an antibiotic and a PPI) and ecabet sodium-based (ecabet plus two antibiotics) triple therapies. Recently, rifabutin has been used in combination with a PPI and amoxycillin as a rescue therapy, with satisfactory eradication rates. In addition, a number of new antimicrobial agents are currently under investigation in in vitro studies but the clinical values of these agents needs to be confirmed.

Amoxicillin/tetracycline combinations are inadequate as alternative therapies for Helicobacter pylori infection

BACKGROUND

Triple therapy with proton pump inhibitors or ranitidine bismuth citrate, clarithromycin and either amoxicillin or nitroimidazole derivatives are the present gold standards for cure of Helicobacter pylori infection. However, primary resistance to either clarithromycin or nitroimidazole derivatives is increasing and alternative therapies are needed.

AIM

To determine the efficacy and safety of three regimens consisting of amoxicillin and tetracycline or doxycycline combined with either lansoprazole or ranitidine bismuth citrate.

METHODS

Two hundred and seventy H. pylori infected patients were randomly given one of the following treatments: amoxicillin 1 g twice a day (b.i.d.) plus tetracycline 500 mg four times a day (q.i.d.) with either lansoprazole 30 mg b.i.d. (group LAT) or ranitidine bismuth citrate 400 mg b.i.d. (group RBCAT) for 7 days and amoxicillin 1 g b.i.d. plus doxycycline 100 mg b.i.d. and lansoprazole 30 mg b.i.d. for 14 days (group LAD). Eradication rate was assessed by UBT at 4-6 weeks after therapy.

RESULTS

The three groups (LAT, RBCAT, and LAD) of patients achieved eradication rates of 35% (25-45), 20% (12-29) and 36% (25-46), respectively, on intention-to-treat analysis. Patient compliance was optimal and side-effects minimal in all three groups.

CONCLUSIONS

Although the amoxicillin/tetracycline combination is attractive (inexpensive, safe, and with low primary resistance rate), it can not be recommended for H. pylori eradication.

High rate of post-therapeutic resistance after failure of macrolide-nitroimidazole triple therapy to cure Helicobacter pylori infection: impact of two second-line therapies in a randomized study

BACKGROUND

The optimal second-line treatment after failed Helicobacter pylori therapy has not been established.

AIMS

To ascertain whether quadruple therapy or triple therapy with omeprazole, clarithromycin and amoxicillin is the superior re-treatment after triple therapy containing a macrolide and a nitroimidazole, and to determine the impact of microbial in vitro resistance.

METHODS

Patients after failed triple therapy were randomly allocated to one of two 1-week second-line treatments: omeprazole, 40 mg, clarithromycin, 500 mg, and amoxicillin, 1 g, all b.d.; or omeprazole, 20 mg b.d., bismuth subsalicylate, 600 mg q.d.s., metronidazole, 400 mg t.d.s., and tetracycline, 500 mg q.d.s. Post-therapeutic Helicobacter pylori status was assessed by 13C-urea breath test at least 4 weeks after treatment.

RESULTS

The study was terminated after including 84 patients. H. pylori cure rates differed significantly: omeprazole-clarithromycin-amoxicillin: intention-to-treat, 43%; per protocol, 50%; omeprazole-bismuth subsalicylate-metronidazole-tetracycline: intention-to-treat, 68%; per protocol, 69%. The frequencies of resistance after first-line therapy were: metronidazole, 90%; clarithromycin, 71%; both combined, 68%. For clarithromycin resistance, H. pylori cure with omeprazole-clarithromycin-amoxicillin was 30% vs. 83% for clarithromycin susceptibility.

CONCLUSIONS

Omeprazole-bismuth subsalicylate-metron- idazole-tetracycline was superior to omeprazole-clarithromycin-amoxicillin, but both therapies yielded unsatisfactory results. The high rate of post-therapeutic dual resistance has a negative impact on omepraz- ole-clarithromycin-amoxicillin, and probably also on omeprazole-bismuth subsalicylate-metronidazole-tetracycline, and limits the choice for second-line treatment.

Treatment of Helicobacter pylori infection. Indications and regimens: an update

The management of Helicobacter pylori infection is still surrounded by controversy and uncertainties. Indications and correct application of current regimens for Helicobacter pylori infection are still considered a matter of debate. Regarding indications, only peptic ulcer and mucosa associated lymphoid tissue lymphoma are considered clear indications for treatment. In other conditions, such as atrophic gastritis, post gastric cancer resection, first-degree relatives of gastric cancer patients, dyspeptic patients, patients with gastro-oesophageal reflux disease and non-steroidal anti-inflammatory drug users, the value of Helicobacter pylori eradication is still controversial. The regimens for first-line and second-line treatment of Helicobacter pylori infection have been recommended by the Maastricht 2 Consensus Report. Although all the treatments are considered to be effective, physicians still do not agree on what first-line regimen should be used. Furthermore, a consensus on the duration of the antibiotic treatment is still lacking, although Maastricht guidelines for treatment of Helicobacter pylori infection recommend a one-week therapy. Also regimens, as a third-line treatment, and methods to improve compliance and clinical outcome are still a matter of debate. All these points will be considered in the present review

Two new treatment regimens for Helicobacter pylori eradication: a randomised study

BACKGROUND

Several studies have found a fairly low Helicobacter pylori eradication rate using a standard 7-day triple therapy in Italy. Recently, two new therapeutic schedules have been proposed with an eradication rate higher than 90%. This study compared the efficacy of these two treatment regimens.

PATIENTS AND METHODS

A total of 131 patients with Helicobacter pylori infection and either non-ulcer dyspepsia (73 patients] or peptic ulcer (58 patients) were enrolled. Helicobacter pylori infection was assessed by rapid urease test and histology on gastric biopsies. Patients were randomised to receive either a 5-day course of ranitidine bismuth citrate 400 mg bid, clarithromycin 500 bid, and tinidazole 500 bid, or a 10-day course of omeprazole 20 mg bid plus amoxycillin 1 g bid for the first 5 days, and omeprazole 20 mg bid, clarithromycin 500 mg bid and tinidazole 500 mg bid for the remaining 5 days. Eradication was assessed by endoscopy 4-6 weeks after therapy.

RESULTS

Overall, 4 patients (2 for each treatment group) were lost to follow-up. Helicobacter pylori eradication rates were 67.2% (95% confidence interval: 55.7-78.7) and 65.2% (95% confidence interval: 53.7-76.6) at per protocol and intention-to-treat analyses, respectively, after the 5-day regimen, and 96.8% (95% confidence interval: 92.5-100) and 93.8% (95% confidence interval: 88-99.7) after the 10-day regimen (p<0.05). Both treatments were well tolerated, and no major side-effects were reported.

CONCLUSIONS

The 5-day regimen gave disappointing results, while the eradication rate after the 10-day regimen was very high.