Helicobacter pylori eradication and gastric ulcer healing--comparison of three pantoprazole-based triple therapies

[1983-2023 - Four decades Helicobacter pylori - what's next?]

Four decades ago the discovery of Helicobacter pylori was first reported in the international medical literature. Since then, there have been significant developments in basic and clinical science that have been translated into daily clinical practice. Changes in the management of H. pylori infection have occurred in diagnostic algorithms, indications for therapy and therapy itself. A special focus is directed to strategies of gastric cancer prevention.This manuscript briefly reviews the milestone in 40 years of H. pylori management.

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.

Clarithromycin Versus Metronidazole in First-Line Helicobacter Pylori Triple Eradication Therapy Based on Resistance to Antimicrobial Agents: Meta-Analysis

Background: International treatment guidelines for Helicobacter pylori infection recommend a proton pump inhibitor (PPI)/amoxicillin/clarithromycin (CAM) regimen (PAC) or PPI/amoxicillin/metronidazole (MNZ) regimen (PAM) as first-line therapy based on culture and sensitivity testing. As incidence rates of antimicrobial agent-resistant strains are changing year by year, it is important to reevaluate the efficacy of eradication regimens. We performed a meta-analysis to evaluate the efficacy and safety of PAC and PAM based on different locations categorized by the reported incidence of CAM- and MNZ-resistant strains. Methods: Randomized control trials (RCTs) comparing eradication rates between PAC and PAM first-line treatment up to December 2018 were included. We divided RCTs into four groups based on resistance to CAM (< 15% or ≥ 15%) and MNZ (< 15% or ≥ 15%). Results: A total of 27 studies (4825 patients) were included. Overall eradication rates between PAC and PAM were similar (74.8% and 72.5%, relative risk (RR): 1.13, 95% confidence interval (CI): 0.91–1.39, P = 0.27) in the intention-to-treat analysis. In areas with low MNZ- and high CAM-resistance rates, PAM had a significantly higher eradication rate than PAC (92.5% vs. 70.8%, RR: 0.29, 95% CI: 0.13–0.68). In areas with high MNZ- and low CAM-resistance rates, the eradication rate with PAC was only 72.9%. Conclusions: Overall eradication rates with PAC and PAM were equivalent worldwide. In low MNZ-resistance areas, PAM may be recommended as first-line therapy. However, the efficacy of PAC may be insufficient, irrespective of susceptibility to CAM.

Proton-pump inhibitor and amoxicillin-based triple therapy containing clarithromycin versus metronidazole for Helicobacter pylori: A meta-analysis

BACKGROUND

Helicobacter pylori (H. pylori) infection is one of the important risk factors of gastric related diseases and antibiotic therapy has become an effective treatment. At present, proton-pump inhibitor and amoxicillin-based triple therapy, including clarithromycin (PAC) and metronidazole (PAM), are two commonly used first-line therapies for H. pylori infection, which has a high incidence and possibly poor prognosis worldwide.

METHODS

A systematic literature review was performed using the databases PubMed, the Cochrane Library, Ovid Medline, Science Direct, Embase, Scopus and Web of Science. Only randomized clinical trials with full texts published were included.

RESULTS

Eighteen studies involving 3264 patients were included. The pooled risk ratios (RR) between the PAC and PAM groups were comparable in the intention-to-treat (ITT) eradication rates (71.0% versus 75.2%, RR = 0.96, p = 0.38) and per-protocol (PP) eradication rates (79.6% versus 80.1%, RR = 1.02, p = 0.65). PAM is highly effective in clarithromycin-resistant cases (70.4% versus 48.2%, RR = 0.65, p = 0.002) and that PAC showed significant efficacy in metronidazole-resistant cases (87.3% versus 58.6%, RR = 1.43, p = 0.0006). In subgroup analysis, when using low-dose PPI, the PAM group showed greater efficacy than the PAC group. Furthermore, we found that PAM showed higher effectiveness in the studies published in recent years, especially for people over 60 years old (RR = 0.80, 95% CI: 0.71-0.89, p < 0.001).

CONCLUSION

In general, both PAC and PAM regimens were effective and comparable in eradicating H. pylori. However, the PAM regimen showed greater efficacy than the PAC regimen in recent years, especially for people over 60 years old.

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.

Prospective single-arm trial of two-week rabeprazole treatment for ulcer healing after gastric endoscopic submucosal dissection

AIM

Endoscopic submucosal dissection (ESD) causes artificial ulcers, and there is no consensus regarding the degree of healing in ESD-induced ulcers or the optimal duration of proton pump inhibitor (PPI) treatment. The aim of the present study was to investigate the healing rates of post-ESD ulcers in response to the protective effect of 2-week PPI treatment.

METHODS

Between February 2007 and March 2010, 75 patients/75 lesions and 55 patients/55 lesions were enrolled as interim and per-protocol groups, respectively. All patients were prescribed rabeprazole (10 mg/day) orally for 16 days beginning on the day before ESD. Follow-up endoscopy was carried out 8 weeks after ESD to evaluate ulcer healing. The primary end-point was the healing rate of post-ESD ulcers at 8 weeks after ESD. Secondary end-points were the rate of post-ESD bleeding with emergency endoscopy and the rate of other severe adverse effects during the study period.

RESULTS

The transitional rate to scarring-stage ulcers was 80.0% (44/55). Location in the lesser curve and large resected size (>40 mm) were statistically significant predictors for delayed ulcer healing by univariate analysis and the latter was still significant by the multivariate analysis. Post-ESD bleeding occurred within 2 weeks in two cases (2.7%), but both cases were successfully managed with endoscopic hemostasis only. Severe adverse effects did not occur.

CONCLUSIONS

Two-week administration of PPI for post-ESD gastric ulcers may be sufficient to aid healing without increasing any adverse effects in cases where there are no possible deteriorating factors on ulcer healing, although large resection and/or resection in the lesser curve may result in delayed healing even after 8 weeks of ESD.

Twelve-month endoscopic and histological analysis following proton-pump inhibitor-based triple therapy in Helicobacter pylori-positive patients with gastric ulcers

OBJECTIVE

To evaluate endoscopic and histological findings after Helicobacter pylori eradication therapy in gastric ulcer (GU) patients after 12 months' follow-up.

MATERIAL AND METHODS

A total of 401 GU patients were randomized to receive either twice-daily (b.i.d.) esomeprazole 20 mg+amoxicillin 1000 mg+clarithromycin 500 mg (EAC) for 1 week followed by placebo for 3 weeks, EAC followed by once-daily (o.d.) esomeprazole 20 mg for 3 weeks or esomeprazole 20 mg b.i.d. plus placebo antibiotics for 1 week followed by esomeprazole 20 mg o.d. for 3 weeks. Endoscopy with biopsy was performed at baseline, after treatment and at 6 and 12 months' follow-up (healed patients).

RESULTS

Endoscopic abnormalities, particularly in the stomach, were common at baseline and remained similar during follow-up, regardless of ulcer status and treatment. Helicobacter gastritis was present (antrum or corpus) in approximately 20% of patients following eradication therapy (versus approximately 80% with esomeprazole alone); these effects were sustained during follow-up. Similar trends were observed for other histological variables (granulocyte and lymphoplasmocytic cell infiltration, replacement of gastric surface cells by regenerative epithelium, and mucous depletion). No changes in atrophy or intestinal metaplasia were observed. Eighteen gastric cancer cases were detected: 11 at baseline endoscopy, and seven during treatment and follow-up.

CONCLUSIONS

Endoscopic abnormalities are common in GU patients and persist after proton-pump inhibitor-based triple therapy for H. pylori eradication, which is associated with large, sustained improvements in histological variables. Follow-up endoscopy and histology may be necessary, even in patients with apparently non-malignant GU, to improve the detection rate of gastric malignancy in populations with a high prevalence of gastric cancer.

Helicobacter pylori eradication therapy may facilitate gastric ulcer healing after endoscopic mucosal resection: a prospective randomized study

BACKGROUND AND AIM

It remains unclear whether Helicobacter pylori eradication therapy affects the healing rate of iatrogenic ulcers following endoscopic mucosal resection (EMR) for gastric tumors. The aim of our study was to prospectively evaluate the effect of H. pylori eradication therapy on gastric ulcer healing after EMR.

METHODS

After EMR, patients were randomly assigned to either the H. pylori eradication group (Hp group) (lansoprazole 30 mg, amoxicillin 1000 mg, and clarithromycin 500 mg, twice a day for 7 days) or the noneradication group (proton pump inhibitor, PPI group) (lansoprazole 30 mg, twice a day for 7 days). Four weeks after EMR, the ulcer stages and size were compared between the two groups. Moreover, ulcer-related symptoms, bleeding rates, adverse effects, and drug compliance were compared.

RESULTS

A total of 64 patients were enrolled. Of these, 17 patients were excluded from the study. The two groups were comparable in terms of baseline clinicopathologic characteristics. Four weeks after EMR, the two groups did not differ with respect to ulcer stage (p = .475) or ulcer-related symptoms (p = .399). However, the ulcer reduction ratio was significantly higher in the Hp group (0.028 +/- 0.024 vs. 0.065 +/- 0.055, p < .05). No differences were observed between the two groups with regard to drug compliance, adverse drug event rates, or bleeding rates.

CONCLUSIONS

Our results suggest that H. pylori eradication therapy might improve the ulcer healing rate after EMR.

Effect of esomeprazole triple therapy on eradication rates of Helicobacter pylori, gastric ulcer healing and prevention of relapse in gastric ulcer patients

OBJECTIVES

To compare esomeprazole-based triple therapy with esomeprazole alone for the eradication of Helicobacter pylori (H. pylori), healing of ulcer and prevention of relapse in H. pylori-related gastric ulcer (GU) diseases.

METHODS

In this double-blind study, 401 H. pylori-positive patients with more than or equal to two GUs were randomized to: esomeprazole (20 mg) twice daily (bid) and amoxicillin (1000 mg) bid and clarithromycin (500 mg) bid (EAC) for 1 week, followed by placebo for 3 weeks (EAC and placebo); EAC for 1 week, followed by esomeprazole (20 mg) once daily (E20) for 3 weeks (EAC and E20); or esomeprazole (20 mg) bid and placebo antimicrobials for 1 week, followed by E20 for 3 weeks (E20 bid and E20). Patients with unhealed GUs at 4 weeks received E20 for an additional 4 weeks. Healed patients were followed up for 12 months.

RESULTS

Eradication rates at 4 weeks or 8 weeks were 82% for EAC and E20, 77% for EAC and placebo and 9.5% for E20 bid and E20 (intention-to-treat analysis). Significantly more patients receiving EAC than those receiving esomeprazole alone remained free of GUs during follow-up [EAC and E20, 90%; EAC and placebo, 87%; P=0.0005 for combined group vs. esomeprazole alone [E20 bid and E20 (74%)]. All treatments were well tolerated.

CONCLUSION

Esomeprazole-based triple therapy is effective for the eradication of H. pylori, healing of GU and prevention of relapse. Esomeprazole monotherapy for 3 weeks after triple therapy may be beneficial in terms of healing.

Helicobacter pylori status and the extent of gastric atrophy do not affect ulcer healing after endoscopic submucosal dissection

BACKGROUND

Eradication therapy for Helicobacter pylori is effective in preventing peptic ulcer recurrence, but its efficacy in ulcer healing is still controversial. The effect of H. pylori on artificial ulcers after endoscopic resection is not known. The purpose of the present study was therefore to evaluate the influence of H. pylori infection on ulcer healing after endoscopic submucosal dissection (ESD).

METHODS

One hundred and 10 patients who underwent ESD for gastric tumors, and for whom the infection status of H. pylori was confirmed before treatment, were included. The healing stage was studied by endoscopy performed at 8 weeks after ESD. In addition, 73 patients whose serum pepsinogen (PG) was evaluated before ESD, were divided into three groups: PG positive (PGI<or=70 ng/mL and I/II<or=3 ng/mL), strongly positive (PGI<or=30 ng/mL and I/II<or=2 ng/mL) and negative, to study the influence of atrophic gastritis on ulcer healing.

RESULTS

Ulcer healing was observed in 85 patients (93%) who were H. pylori positive, and in 19 patients (100%) in whom H. pylori had been eradicated previously. Serum PG level had no influence on the healing process. Among 15 patients with ulceration or ulcer scar with the lesion, ulcer healing was observed in nine patients (60%), which was significantly low.

CONCLUSIONS

Infection status of H. pylori and the extent of gastric atrophy do not affect ulcer healing after ESD. Preoperative existence of fibrotic change in the submucosal layer may delay the healing process.

Ulkuskrankheit

Treatment of peptic ulcer disease has undergone a radical change due to the discovery of its main cause, the Helicobacter pylori infection. The management of the chronic infection is now the primary aim. Treatment of peptic ulcer essentially consists of eradicating H. pylori. A current problem is the resistance developed by H. pylori to the antibiotics used in eradication regimen. Ulcers that are induced by nonsteroidal antirheumatic (NSAR) agents and acetylsalicylic acid are gaining in importance. Optimized inhibition of acid secretion with proton pump inhibitors has made it possible to both prevent and cure ulcers in the stomach and duodenum caused by NSAR agents.

Can gastric cancer be prevented by Helicobacter pylori eradication?

Helicobacter pylori infection always causes chronic gastritis and triggers several gastroduodenal pathologies ranging from peptic ulcer disease to gastric cancer. It is well established that H. pylori eradication decreases the incidence of gastroduodenal ulcer and its recurrence. However, despite being accepted as the critical risk factor for gastric cancer, there is no conclusive evidence that H. pylori eradication decreases the incidence of gastric cancer. Bacterial virulence characteristics, as well as genetic predisposition of the host in conjunction with certain environmental conditions, are the major factors which influence the development of gastric cancer. Preclinical and clinical data suggest that reversibility of precancerous lesions (atrophic gastritis and intestinal metaplasia) is possible in some patients after H. pylori eradication. Since neoplastic lesions do not progress - or even regress in some cases - after H. pylori eradication, eradication therapy should be considered even in patients with precancerous lesions. Nonetheless, progression of atrophic gastritis and intestinal metaplasia into cancer has been also demonstrated in patients after H. pylori eradication, suggesting that there might be a point of no return where genetic changes have already happened and are irreversible despite elimination of the triggering carcinogen (H. pylori). At the present time the clinical decision to treat a patient is based on established risk profiles. A general screen-and-treat policy, although desirable, currently awaits a less complex treatment regimen.

Pharmacodynamic comparison of pantoprazole enantiomers: inhibition of acid-related lesions and acid secretion in rats and guinea-pigs

Pantoprazole is an irreversible proton pump inhibitor that is administered as a racemic mixture clinically. The effects of pantoprazole sodium (PAN.Na) enantiomers on acid-related lesions were compared using models of pylorus ligation induced ulcer, histamine induced ulcer and reflux oesophagitis in rats and guinea-pigs. Compared with (+)-PAN.Na and (+/-)-PAN.Na, (-)-PAN.Na showed much stronger inhibitory effects on pylorus ligation induced and histamine induced ulcers, but similar effects on reflux oesophagitis. The doses of (-)-PAN.Na, (+)-PAN.Na and (+/-)-PAN.Na required for 50% inhibition (ID50) of acid-related lesions were 1.28, 5.03 and 3.40 mg kg(-1) against pylorus ligation induced ulcer, 1.20, 4.28 and 3.15 mg kg(-1) against histamine induced ulcer, and 2.92, 3.56 and 3.70 mg kg(-1) against reflux oesophagitis, respectively. The inhibitory effects of PAN.Na enantiomers on basal gastric acid output were compared in rats with acute fistula. In contrast to inhibitory rates of 89.3% and 83.6% on gastric acid output by (-)-PAN.Na and (+/-)-PAN.Na at 1.5 mg kg(-1), (+)-PAN.Na had an inhibitory rate of only 24.7% at the same dose. The above results indicate that (-)-PAN.Na is more potent than (+)-PAN.Na at inhibiting acid-related lesions owing to its stronger inhibition of acid secretion.

Helicobacter pylori eradication has the potential to prevent gastric cancer: a state-of-the-art critique

Helicobacter pylori infection continues to play a key role in gastric diseases. Colonization of the gastric mucosa with the bacterium invariably results in the development of chronic gastritis and subsets of patients have a progression of the chronic gastritis to either ulcer or cancer. Epidemiological evidence indicates that the proportion of all gastric cancers attributable to H. pylori infection, and hence potentially preventable upon elimination of this risk factor, is somewhere in the range of 60% to 90%. This portends significant benefit in terms of morbidity and mortality, not least in populations with high prevalence of H. pylori infection coupled with high incidence of gastric cancer. The effect of prophylactic H. pylori eradication on gastric cancer incidence in humans remains unknown, however. Results from randomized trials are eagerly awaited, but availability of strong conclusive results may take many years. A growing number of studies show considerable variation in risk for gastric cancer development, depending on H. pylori strain type and the genetic predisposition of the host. There is also a remote possibility that elimination of the infection may have adverse health implications (e.g., antibiotic resistance), and therefore "simple" risk stratification and targeted chemoprevention is required. Based on "in depth" evidence presented at this workshop, the majority of the scientific task force favored a search-and-treat strategy in first-degree relatives of gastric cancer patients and an overwhelming majority felt that a more general screen-and-treat strategy should be focused in the first instance on a population with a high incidence of H. pylori-associated diseases.

Efficacy of omeprazole and amoxicillin with either clarithromycin or metronidazole on eradication of Helicobacter pylori in Chinese peptic ulcer patients

AIM: One-week triple therapy with proton pump inhibitors, clarithromycin and amoxicillin has recently been proposed as the first-line treatment for Helicobacter pylori (H pylori) infection; however, data regarding the effects of this regimen in China are scarce. The aim of this prospective and randomized study was to compare the efficacy of clarithromycin and metronidazole when they were combined with omeprazole and amoxicillin on eradication of H pylori and ulcer healing in Chinese peptic ulcer patients.

METHODS: A total of 103 subjects with H pylori-positive peptic ulcer were randomly divided into two groups, and accepted triple therapy with omeprazole 20 mg, amoxicillin 1000 mg and either clarithromycin 500 mg (OAC group, n = 58) or metronidazole 400 mg (OAM group, n = 45). All drugs were given twice daily for 7 d. Patients with active peptic ulcer were treated with omeprazole 20 mg daily for 2-4 wk after anti-H pylori therapy. Six to eight weeks after omeprazole therapy, all patients underwent endoscopies and four biopsies (two from the antrum and two others from the corpus of stomach) were taken for rapid urease test and histological analysis (with modified Giemsa staining) to examine H pylori. Successful eradication was defined as negative results from both examination methods.

RESULTS: One hundred patients completed the entire course of therapy and returned for follow-up. The eradication rate of H pylori for the per-protocol analysis was 89.3% (50/56) in OAC group and 84.1% (37/44) in OAM group. Based on the intention-to-treat analysis, the eradication rate of H pylori was 86.2% (50/58) in OAC group and 82.2% (37/45) in OAM group. There were no significant differences in eradication rates between the two groups on either analysis. The active ulcer-healing rate was 96.7% (29/30) in OAC group and 100% (21/21) in OAM group (per-protocol analysis, P>0.05). Six patients in OAC group (10.3%) and five in OAM group (11.1%) reported adverse events (P>0.05).

CONCLUSION: One-week triple therapy with omeprazole and amoxicillin in combination with either clarithromycin or metronidazole is effective for the eradication of H pylori. The therapeutic regimen comprising metronidazole with low cost, good compliance and mild adverse events may offer a good choice for the treatment of peptic ulcers associated with H pylori infection in China.

Effects of killing Helicobacter pylori quadruple therapy on peptic ulcer: A randomized double-blind clinical trial

AIM: To study the therapeutic efficacy of a Chinese and Western integrated regimen, killing Helicobacter pylori quadruple therapy on H pylori-associated peptic ulcers (PU).

METHODS: With prospective and double-blind controlled method, seventy-five active PU patients with H pylori infection were randomized to receive one of the following three regimens: (1) new triple therapy (group A: lansoprazole 30 mg qd, plus clarithromycin 250 mg bid, plus amoxycillin 500 mg tid, each for 10 d); (2) killing Hp quadruple therapy(group B: the three above drugs plus killing H pylori capsule 6 capsules bid for 4 wk) and (3) placebo(group C: gastropine 3 tablets bid for 4 wk). H pylori eradication and ulcer healing quality were evaluated under an endoscope 4 wk after treatment. The patients were followed up for 5 years.

RESULTS: Both the healing rate of PU and H pylori eradication rate in group B were significantly higher than those in group C (100% and 96.4% vs 20% and 0%, respectively, P<0.005), but there was no significant difference compared to those in group A (88% and 92%, P>0.05). The healing quality of ulcer in group B was superior to that in groups C and A (P<0.05). The recurrence rate of PU in group B (4%) was lower than that in group A (10%) and group C (100%, P<0.01).

CONCLUSION: Killing Helicobacter pylori quadruple therapy can not only promote the eradication of H pylori and healing quality of ulcer but also reduce recurrence rate of ulcer.

Human polymeric IgA is superior to IgG and single-chain Fv of the same monoclonal specificity to inhibit urease activity associated with Helicobacter pylori

Helicobacter-induced gastritis is considered nowadays an epidemic, the prevalence of which is one of the highest world-wide (70%), with as much as 40% of the population in industrialized countries. Helicobacter pylori (H. pylori) antigens (Ag) capable to elicit a protective immune response in animal models have been identified, but these antigens have not been shown to be strongly immunogenic when administered to humans. Due to their stability in the gastric environment and avidity, passive administration of secretory immunoglobulin A (SIgA) antibodies (Ab) targeting protective Ag might be particularly relevant as a substitute or complement to current therapies. To this aim, we have designed expression vectors to convert a scFv polypeptide specific for H. pylori urease subunit A into human IgG, polymeric IgA (IgAp/d) and SIgA. Purified proteins show proper binding characteristics toward both the native and denatured forms of H. pylori urease. The direct comparison between different isotype and molecular forms, but of unique specificity, demonstrates that SIgA and IgAp/d are more efficient in blocking free and H. pylori-associated urease than IgG and scFv. We conclude that the expression system reported herein will represent a valuable tool to produce human SIgA Ab of multiple specificities against H. pylori antigens involved in colonization and persistence.

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.

Eradication of Helicobacter pylori by 7-day triple-therapy regimens combining pantoprazole with clarithromycin, metronidazole, or amoxicillin in patients with peptic ulcer disease: results of two double-blind, randomized studies

AIM

To compare the short-term (7-day) safety and efficacy of two triple-therapy regimens using pantoprazole with those of two dual-therapy regimens (one with pantoprazole and one without), for Helicobacter pylori eradication in patients with peptic ulcer disease.

METHODS

H. pylori infection was identified by rapid urease (CLOtest), and confirmed by histology and culture. Patients were enrolled into one of two randomized, double-blind, multicenter, parallel-group studies. In study A, patients received oral pantoprazole 40 mg, clarithromycin 500 mg, and metronidazole 500 mg (PCM); pantoprazole, clarithromycin and amoxicillin 1000 mg (PCA); or pantoprazole and clarithromycin (PC). In study B, patients received PCM, PCA, PC, or clarithromycin and metronidazole without pantoprazole (CM). Treatments were given twice daily for 7 days. H. pylori status after therapy was assessed by histology and culture at 4 weeks after completing the course of study treatment. Modified intent-to-treat (MITT; each study: n = 424, n = 512) and per-protocol (PP; each study: n = 371, n = 454) populations were analyzed. The MITT population comprised all patients whose positive H. pylori status was confirmed by culture and histology; the PP population comprised patients who also complied with > or = 85% of study medication doses.

RESULTS

A total of 1016 patients were enrolled. Cure rates among patients with clarithromycin-susceptible H. pylori strains were 82 and 86% for PCM, and 72 and 71% for PCA, in studies A and B, respectively. Cure rates among patients with metronidazole-susceptible H. pylori strains were 82 and 87% for PCM, and 71 and 69% for PCA, in studies A and B, respectively. The combined eradication rates observed with the PCM regimen were superior to those of all other regimens tested. Side-effects were infrequent and mild.

CONCLUSIONS

PCM had the highest overall eradication rate in these two studies examining 7-day treatment regimens. All regimens were safe and well tolerated.