Rifabutin-Based Triple Therapy (RHB-105) for Helicobacter pylori Eradication: A Double-Blind, Randomized, Controlled Trial

Safety, pharmacokinetics, and efficacy of rifasutenizol, a novel dual-targeted antibacterial agent in healthy participants and patients in China with Helicobacter pylori infection: four randomised clinical trials

BACKGROUND

Due to the rapid development of antimicrobial resistance, the efficacy of most Helicobacter pylori eradication therapies have progressively decreased to an unacceptable level. Rifasutenizol (TNP-2198) is a new molecular entity with a synergistic dual mechanism of action currently under clinical development for the treatment of microaerophilic and anaerobic bacterial infections. We aimed to evaluate the safety, pharmacokinetics, and efficacy of rifasutenizol in healthy Chinese participants and patients with H pylori.

METHODS

We conducted four clinical trials of rifasutenizol capsules in healthy participants (aged 18-55 years) and patients with asymptomatic H pylori infection (aged 18-65 years) in a clinical trial centre in Jilin province, China. Trial 1 was a phase 1, double-blind, randomised, placebo-controlled, single ascending dose study, in which participants were enrolled into one of seven rifasutenizol dose groups (50 mg, 100 mg, 200 mg, 400 mg, 600 mg, 800 mg, or 1000 mg) and were randomly assigned in a 4:1 ratio to study drug or placebo. Trial 2 was a phase 1, double-blind, randomised, placebo-controlled, multiple ascending dose study, in which patients were enrolled into one of three rifasutenizol dose groups (200 mg, 400 mg, or 600 mg) and were randomly assigned in a 3:1 ratio to study drug or placebo. Trial 3 was a phase 2a, open-label, randomised, multiple-dose, dose-finding study in which patients enrolled into one of four cohorts were randomly assigned in a 1:1:1:1 ratio to a rifasutenizol dual or triple regimen. Trial 4 was a phase 2b, open-label, randomised, multiple-dose, regimen exploration study, in which patients enrolled into one of five cohorts were randomly assigned in a 2:2:1:1:2 ratio to a rifasutenizol dual therapy, triple therapy, or a control cohort. Block randomisation (block size 4 or 8) was used in all four trials. The key primary endpoints for trials 1, 2, and 3 were the tolerability, safety, and pharmacokinetics of rifasutenizol. For trial 4, the primary endpoint was the eradication rate of H pylori. These four trials were registered at ClinicalTrials.gov (NCT06081699, NCT06081712, NCT06076681, and NCT06076694) and chinadrugtrials.org.cn (CTR20190734, CTR20192553, CTR20212050, and CTR20220625) and are completed.

FINDINGS

Between May 9, 2019, and Sept 14, 2022, 78 healthy participants (trial 1: n=10 per cohort in a 4:1 rifasutenizol:placebo ratio; and an additional eight for the food-effect cohort) and 168 patients with asymptomatic H pylori infection (trial 2: n=16 per cohort in a 3:1 rifasutenizol:placebo ratio; trial 3: n=10 per cohort; trial 4: n=10 or n=20 per cohort) were enrolled in the four clinical trials. Single doses of rifasutenizol (50-1000 mg) and multiple doses of rifasutenizol (200 mg to 600 mg, twice a day), either as monotherapy or co-administered with rabeprazole and amoxicillin, showed favourable safety and tolerability profiles. Most adverse events were mild, and no serious adverse events were reported. Rifasutenizol demonstrated a linear pharmacokinetic profile over the dose range of 50-800 mg, and there were no apparent pharmacokinetic interactions between rifasutenizol and the co-administrated drugs. Food intake slightly elevated the area under the plasma concentration-time curve (AUC) of rifasutenizol, and the geometric mean of AUC from time 0 to the last timepoint with a quantifiable concentration (AUC0-t) and AUC from time 0 to infinity (AUC0-∞) in the fed state were 1·334 and 1·396 times of those in the fasted state, respectively. There was mild accumulation after continuous administration of rifasutenizol, and the Rac(AUC) of rifasutenizol 400 mg in the dual and triple regiments in trial 3 were 1·37 and 1·49, respectively. In trial 3, the eradication rates of H pylori with 200 mg, 400 mg, or 600 mg of rifasutenizol in combination with rabeprazole, twice a day for 14 days, were 0% (95% CI 0-31), 30% (7-65), and 40% (12-74), respectively, identifying rifasutenizol 400 mg as the effective dose. In trial 4, H pylori eradication rates with the triple regimen in cohort A (400 mg rifasutenizol, 20 mg rabeprazole sodium, and 1 g amoxicillin) twice a day for 14 days was 95% (95% CI 74-100), and triple therapy (600 mg rifasutenizol, 20 mg rabeprazole sodium, and 1 g amoxicillin) three times a day for 7 days was 100% (69-100).

INTERPRETATION

Rifasutenizol monotherapy and combination therapy was generally safe and well tolerated in healthy participants and patients with H pylori infection. A triple regimen of 400 mg rifasutenizol capsules, 20 mg rabeprazole sodium enteric-coated tablets, and 1 g amoxicillin capsules twice a day for 14 days showed promising efficacy as a new treatment regimen for H pylori infection.

FUNDING

TenNor Therapeutics and National Natural Science Foundation of China.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Safety profile of Helicobacter pylori eradication treatments: literature review and updated data of the European Registry on Helicobacter pylori management (Hp-EuReg)

INTRODUCTION

Helicobacter pylori (H. pylori), the most prevalent chronic infection globally, is the major cause of relevant diseases such as gastric cancer, leading to high morbidity and mortality worldwide. Several studies have focused on optimize H. pylori eradication treatment through combination therapies and antibiotic resistance. However, the adverse events profile and its impact, as a primary outcome, remains underexplored.The aim of this review was to summarize the available data on the safety of the most common regimens for H. pylori eradication and its impact on the compliance.

AREAS COVERED

This review encompassed the published evidence from the years 2008 to 2023 regarding both the safety and compliance for most common H. pylori eradication regimens. The main sources for this review comprised MEDLINE, PubMed, and Cochrane electronic databases. Furthermore, it included a safety analysis of unpublished data from the European Registry on H. pylori management (Hp-EuReg).

EXPERT OPINION

Poor compliance is correlated with significantly lower cure rates, and this is a unique modifiable source of H. pylori treatment failure. Eradication treatments have become complex, involving multiple drugs and dosing intervals. Thus, patient education is crucial; doctors must explain to the patient about potential temporary and most often harmless side effects.

Helicobacter pylori Infection: A 40-Year Journey through Shifting the Paradigm to Transforming the Management

BACKGROUND

Helicobacter pylori (H. pylori) was discovered 40 years ago and has set a milestone in human medicine. The discovery led to rejection of the dogma of the acidic stomach as a sterile organ and requested to rewrite the chapters on gastric pathophysiology and gastroduodenal diseases.

SUMMARY

Over a period of 40 years following the discovery, more than 50,000 articles can be retrieved in PubMed as of today and illustrate the amount and the intensity of research around the role of this bacterium. H. pylori emerged as cause of chronic gastritis and principal cause of peptic ulcer disease (PUD). Eradication of H. pylori became standard of care in management in PUD. The importance of this was highlighted in 2005 with the Nobel Prize in Medicine awarded to Barry Marshall and Robin Warren. H. pylori became eventually recognized for its oncogenic potential in the stomach and as the main risk factor for gastric cancer development.

KEY MESSAGES

H. pylori gastritis is defined as infectious disease and requires therapy in all infected individuals. Strategies of gastric cancer prevention and development of therapies to overcome the increasing antibiotic resistance are main targets in clinical research of today.

Evolving Concepts in Helicobacter pylori Management

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

Clarifying varied Helicobacter pylori eradication therapies: A comprehensive review

Current global variations exist in Helicobacter pylori (H. pylori) eradication regimens. Triple therapy (TT), bismuth quadruple therapy (BQT), and high-dose dual therapy (HDDT) currently represent the predominant regimens. These regimens diverge in terms of treatment duration, the utilization of susceptibility testing, acid-inhibiting drug administration, and patient education. We conducted a comprehensive systematic literature review on these H. pylori treatment regimens. Our review aims to provide standardized treatment recommendations for H. pylori, reducing the risk of amalgamating findings from diverse eradication regimens. Recent research suggests that the optimal treatment duration for TT and BQT may be 14 and 10 days, respectively. Selecting the appropriate treatment duration for HDDT should rely on regional research evidence, and 14 days may be the optimal duration. The incorporation of susceptibility testing in TT is of paramount importance. In the case of BQT, the absence of susceptibility testing may be considered as an option, contingent upon cost and availability, and should be determined based on local antibiotic resistance patterns and the efficacy of empirical regimens. The type and dosage of acid-inhibiting drug would affect the efficacy of these regimens. Acid-inhibiting drugs should be selected and applied reasonably according to the population and therapies. Adequate patient education plays a pivotal role in the eradication of H. pylori. In regions with accessible local research evidence, the 10-day empirical BQT regimen may be considered a preferred choice for H. pylori eradication.

Effectiveness of Rifabutin-Based Regimens in Treating Helicobacter pylori Infections

Helicobacter pylori has been reported as a health problem worldwide, affecting a sizable portion of people. Peptic ulcers, gastric cancer, and various extra gastric conditions are associated with this bacterium. The rampant overprescribing of antibiotics has led to the emergence of H. pylori strains resistant to multiple antibiotics, causing a decline in the effectiveness of current treatments. Recently, there has been growing interest in researching alternative treatment options for H. pylori infections that do not respond to initial therapy. Rifabutin, a rifamycin derivative initially designed for tuberculosis treatment and preventing Mycobacterium avium complex infection, has gained attention as a potential rescue medication. It has shown efficacy against H. pylori and the potential to eradicate the bacterium when combined with other antibiotics. This systematic review article focuses on using rifabutin-based regimens as a treatment option after initial treatments have failed. The authors screened literature published in the last five years, between 2017 and 2022, across various search engines and closely examined relevant studies following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. The search covered a variety of electronic databases and focused on H. pylori gastritis, rifabutin-based treatment plans, and in vivo investigations in healthy individuals. The comprehensive review provides convincing evidence that rifabutin-based regimens are effective rescue treatments for H. pylori infections. Multiple studies in various areas consistently demonstrated high eradication rates, ranging from 70% to 90%, when rifabutin-containing regimens were used. The analysis found that only a tiny percentage of H. pylori strains (1%) were resistant to rifabutin therapy, further supporting the viability of Rifabutin as an alternative when other antibiotics failed to eradicate H. pylori. The cost of Rifabutin is a significant factor that may limit its accessibility, particularly in resource-constrained settings where H. pylori infection is common. Moreover, the potential side effects of Rifabutin, such as hematological problems, rashes, and digestive issues, need to be considered. However, these side effects are typically manageable and can be reduced by combining Rifabutin with other antibiotics. In conclusion, this systematic review provides evidence supporting the effectiveness of regimens derived from Rifabutin in eliminating H. pylori infections after initial therapy failure. Due to the observation that Rifabutin effectively eradicates resistant H. pylori infections, it can be considered a suitable choice for rescue therapy. Rifabutin-containing regimens should be reserved as fourth- or later-line therapy options, considering economic factors, the risk of microbial resistance, potential side effects, and the availability of alternative medications. Future research should focus on optimizing rifabutin-based regimens and investigating combination therapies that have better H. pylori eradication rates while also addressing the problem of resistant strains.

Current paradigms in the management of refractory Helicobacter pylori infection

Helicobacter pylori is the most prevalent chronic bacterial infection, with approximately half of the world's population estimated to be colonized. The World Health Organization (WHO) has classified Helicobacter pylori as a class-I carcinogen. All main society guidelines recommend its eradication in infected individuals. The global trend indicates that eradication rates are decreasing annually and the likelihood of eradication decreases with each unsuccessful therapeutic attempt. Resistance to antibiotics in H. pylori strains is the leading cause for eradication failure. Still, drug resistance and treatment failure may be complex, multi-dimensional and associated with several other factors. Knowledge of these factors can aid in optimizing eradication rates. This review will focus on the factors associated with refractory H. pylori, with a particular emphasis on antibiotic resistance mechanisms and their clinical implications. Also, the most recent literature and recommendations available for determining an appropriate regimen after the failure of the first attempt at eradication will be discussed.

Helicobacter pylori infection: a dynamic process from diagnosis to treatment

Helicobacter pylori, a gram-negative microaerophilic pathogen, causes several upper gastrointestinal diseases, such as chronic gastritis, peptic ulcer disease, and gastric cancer. For the diseases listed above, H. pylori has different pathogenic mechanisms, including colonization and virulence factor expression. It is essential to make accurate diagnoses and provide patients with effective treatment to achieve positive clinical outcomes. Detection of H. pylori can be accomplished invasively and noninvasively, with both having advantages and limitations. To enhance therapeutic outcomes, novel therapeutic regimens, as well as adjunctive therapies with probiotics and traditional Chinese medicine, have been attempted along with traditional empiric treatments, such as triple and bismuth quadruple therapies. An H. pylori infection, however, is difficult to eradicate during treatment owing to bacterial resistance, and there is no commonly available preventive vaccine. The purpose of this review is to provide an overview of our understanding of H. pylori infections and to highlight current treatment and diagnostic options.

Rifabutin-Containing Triple Therapy Versus Bismuth Quadruple Therapy for Helicobacter pylori Rescue Treatment: A Multicenter, Randomized Controlled Trial

BACKGROUND

We compared the efficacy and safety of rifabutin-containing triple therapy with bismuth quadruple therapy for rescue treatment of Helicobacter pylori.

METHODS

This was a noninferiority study trial of H. pylori treatment for subjects who had failed at least 2 prior treatments. Subjects were randomly assigned to receive rifabutin triple therapy with 14-day esomeprazole (20 mg), amoxicillin (1.0 g), and rifabutin (150 mg) twice a day; or bismuth quadruple therapy with esomeprazole (20 mg) and bismuth (220 mg) twice a day, plus metronidazole (400 mg) and tetracycline (500 mg) 4 times a day. Antimicrobial susceptibility was assessed by agar dilution and E-test.

RESULTS

From May 2021 to October 2022, a total of 364 subjects were randomized. The eradication rates by intention-to-treat, per-protocol, and modified intention-to-treat were 89.0% (162/182; 95% confidence interval [CI], 83.6%-92.8%), 94.0% (157/167; 95% CI, 89.3%-96.7%), and 93.6% (162/173; 95% CI, 89.0%-96.4%) for rifabutin triple group. For bismuth quadruple group, they were 89.6% (163/182; 95% CI, 84.3%-93.2%), 95.3% (143/150; 95% CI, 90.7%-97.7%), and 93.7% (163/174; 95% CI, 89.0%-96.4%).

CONCLUSIONS

The rifabutin triple therapy is an alternative to classical bismuth quadruple therapy for the rescue treatment of H. pylori with fewer side effects and higher compliance.

CLINICAL TRIALS REGISTRATION

NCT04879992.

Helicobacter pylori in the post-antibiotics era: from virulence factors to new drug targets and therapeutic agents

Helicobacter pylori is considered one of the most prevalent human pathogenic microbes globally. It is the main cause of a number of gastrointestinal ailments, including peptic and duodenal ulcers, and gastric tumors with high mortality rates. Thus, eradication of H. pylori is necessary to prevent gastric cancer. Still, the rise in antibiotic resistance is the most important challenge for eradication strategies. Better consideration of H. pylori virulence factors, pathogenesis, and resistance is required for better eradication rates and, thus, prevention of gastrointestinal malignancy. This article is aimed to show the role of virulence factors of H. pylori. Some are involved in its survival in the harsh environment of the human gastric lumen, and others are related to pathogenesis and the infection process. Furthermore, this work has highlighted the recent advancement in H. pylori treatment, as well as antibiotic resistance as a main challenge in H. pylori eradication. Also, we tried to provide an updated summary of the evolving H. pylori control strategies and the potential alternative drugs to fight this lethal resistant pathogen. Recent studies have focused on evaluating the efficacy of alternative regimens (such as sequential, hybrid, concomitant treatment, vonoprazan (VPZ)-based triple therapy, high-dose PPI-amoxicillin dual therapy, probiotics augmented triple therapy, or in combination with BQT) in the effective eradication of H. pylori. Thus, innovating new anti-H. pylori drugs and establishing H. pylori databanks are upcoming necessities in the near future.

Helicobacter pylori Treatment Regimen Selection and Eradication Rates Across Department of Defense Patients for Fiscal Years 2016-2018

INTRODUCTION

The objective of this study was to measure the number of treatment successes and failures of various Helicobacter pylori treatment regimens among DoD beneficiaries.

MATERIALS AND METHODS

This was a retrospective cross-sectional study of all adult DoD beneficiaries with H. pylori diagnosis, treatment, and eradication testing from October 2015 to September 2018. All stool antigen testing, urea breath test, and immunoglobulin G serologies were identified. Patients were excluded if they did not have a positive test, did not have treatment, or did not have eradication testing.

RESULTS

In total, 20,548 H. pylori diagnostic tests were performed over the study period. A total of 1,592 non-active duty and 374 active duty patients were diagnosed with H. pylori, were treated, and had eradication testing. The best performing regimens were tetracycline-based bismuth quadruple therapy and tinidazole-based clarithromycin triple therapy with eradication rates of 85% and 82%, respectively. Clarithromycin triple therapy was the most prescribed (63.9% of all regimens included in analysis). Of the 1,592 non-active duty and 374 active duty patients, 75.5% (1,202) and 70.6% (264) cleared the infection with treatment, respectively (P = 0.0449). Although trends were identified in differences in geographic eradication rates, none of these achieved the threshold of significance.

CONCLUSIONS

This is the largest and most geographically widespread H. pylori treatment efficacy study in the USA over 20 years. None of the treatment regimens (when used in over five patients) achieved an eradication rate greater than 90%, but tetracycline-based bismuth quadruple therapy performed best among all regimens and populations. Eradication rates were lower in the active duty populations, with no treatment regimen achieving an eradication rate greater than 80%.

Physiologically-based pharmacokinetic modelling to predict intragastric rifabutin concentrations in the treatment of Helicobacter pylori infection

BACKGROUND

Sustained intragastric antibiotic exposure is important for Helicobacter pylori eradication, yet little is known about gastric pharmacology of commonly used H. pylori regimens. For rifabutin, differing intragastric concentrations based on dosing regimen may account for differences in reported eradication rates.

AIM

To compare intragastric rifabutin concentrations between low-dose rifabutin (50 mg three time daily; as in RHB-105) and generically dosed rifabutin 150 mg once daily, 150 mg twice daily, and 300 mg once daily using a validated Physiologically-based pharmacokinetic (PBPK) model.

METHODS

We obtained plasma pharmacokinetic data from the RHB-105 clinical development programs and used it to develop and validate a whole-body PBPK model using PK-SIM software. We modified the existing rifabutin model to include the impact of omeprazole on gastric pH and emptying time. Modelled intragastric rifabutin exposure was expressed as the time that each regimen maintained its concentration ≥MIC90 .

RESULTS

Rifabutin 50 mg three times daily achieved significantly longer times with intragastric concentration above MIC90 (22.3 ± 1.1 h) than 150 mg once daily (8.3 ± 1.7 h), 150 mg twice daily (16.3 ± 2.3 h), or 300 mg once daily (8.5 ± 1.9 h) while providing the lowest mean maximal plasma concentration and mean area under the plasma concentration-time curve of all regimens studied.

CONCLUSIONS

PBPK modelling showed rifabutin 50 mg three times daily had higher intragastric exposure times than 150 mg once daily or twice daily, or 300 mg once daily. This low-dose rifabutin regimen provides the highest potential for H. pylori eradication while minimising systemic rifabutin exposure.

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.

Cost-Effectiveness of Vonoprazan-Based and Rifabutin-Based vs Other Regimens as First-Line Treatment of Helicobacter pylori Infection in the United States

INTRODUCTION

The economic and clinical implications of eradicating Helicobacter pylori ( H. pylori ) with vonoprazan-based and rifabutin-based regimens vs other existing prepackaged first-line treatment options in the United States are unknown. Therefore, we evaluated the cost-effectiveness of vonoprazan-based and rifabutin-based and other prepackaged regimens for the first-line treatment of H. pylori from the perspective of US healthcare payers.

METHODS

We used the state-transition Markov model to conduct a cost-effectiveness analysis of H. pylori eradication with clarithromycin triple, bismuth quadruple, vonoprazan dual, vonoprazan triple, and rifabutin triple regimens. In a cycle length of 2 months, the model estimated the expected costs (expressed in 2022 US$), expected quality-adjusted life-years (QALY), incremental cost-effectiveness ratios, and expected net monetary benefit over 20 years. In addition, we accounted for the present value of future costs and QALY by applying a 3% discounting rate.

RESULTS

In this study, rifabutin triple therapy had a lower expected cost but was more effective than clarithromycin triple, bismuth quadruple, and vonoprazan dual regimens; hence, it dominated them. Vonoprazan triple therapy had a higher expected cost (US$ 1,172 vs US$ 1,048) and expected QALY (14.262 vs 14.256) than rifabutin triple therapy, yielding an estimated incremental cost-effectiveness ratio of US$ 22,573/QALY. The study suggested that vonoprazan triple treatment had the highest expected net monetary benefit and was the most cost-effective at willingness-to-pay thresholds between US$50,000 and US$150,000 per QALY, followed by rifabutin triple therapy.

DISCUSSION

H. pylori infection eradication with vonoprazan triple therapy would provide the greatest net health and monetary benefit from the perspective of US healthcare payers.

Molecular Mechanisms of Antibiotic Resistance and Novel Treatment Strategies for Helicobacter pylori Infections

Helicobacter pylori infects approximately 50% of the world's population and is considered the major etiological agent of severe gastric diseases, such as peptic ulcers and gastric carcinoma. Increasing resistance to standard antibiotics has now led to an ever-decreasing efficacy of eradication therapies and the development of novel and improved regimens for treatment is urgently required. Substantial progress has been made over the past few years in the identification of molecular mechanisms which are conducive to resistant phenotypes as well as for efficient strategies to counteract strain resistance and to avoid the use of ineffective antibiotics. These involve molecular testing methods, improved salvage therapies, and the discovery of novel and potent antimicrobial compounds. High rates of prevalence and gastric cancer are currently observed in Asian countries, including Japan, China, Korea, and Taiwan, where concomitantly intensive research efforts were initiated to explore advanced eradication regimens aimed at reducing the risk of gastric cancer. In this review, we present an overview of the known molecular mechanisms of antibiotic resistance and discuss recent intervention strategies for H. pylori diseases, with a view of the research progress in Asian countries.

The Inappropriateness of Using Rifampicin E-Test to Predict Rifabutin Resistance in Helicobacter pylori

BACKGROUND

The aim of this study was to evaluate the rifamycin cross-resistance in Helicobacter pylori, and whether the use of rifampicin E-test strips to screen H. pylori rifabutin resistance is appropriate.

METHODS

A total of 89 H. pylori isolates were included. Rifampicin minimum inhibitory concentrations (MICs) were obtained by E-test, while the MICs for rifapentine, rifaximin, and rifabutin were determined by agar dilution method. The rifamycin resistance rates based on different breakpoints were compared. Isolates with high-level rifampicin resistance were subjected to whole-genome sequencing.

RESULTS

A wide distribution of MICs (mostly in the range 0.125-8 mg/L) was observed for rifampicin, rifapentine, and rifaximin. Using MIC >1, ≥ 4, and > 4 mg/L as the breakpoints, resistance rates to rifampicin/rifapentine/rifaximin were 60.4%/48.3%/38.2%, 28.1%/25.8%/23.6%, and 15.7%/16.9%/7.9%, respectively. However, the rifabutin MICs of all the tested H. pylori isolates were extremely low (≤0.016 mg/L). Applying MIC ≥ 0.125 mg/L as the breakpoint, rifabutin resistance was nil. No mutation was found in the rpoB gene sequences of the 2 isolates with high-level rifampicin resistance.

CONCLUSIONS

There is a lack of cross-resistance between rifabutin and other rifamycins in H. pylori. The use of rifampicin E-test to predict H. pylori rifabutin resistance is inappropriate.

Reassessment of the Broth Microdilution Method for Susceptibility Testing of Helicobacter pylori

BACKGROUND

Helicobacter pylori infection is an infectious disease and thus the eradication treatment should be guided by susceptibility testing. This study aimed to assess the applicability of broth microdilution as a routine susceptibility testing method for H. pylori.

METHODS

Susceptibility profiles of clarithromycin (CLR) and levofloxacin (LEV) resistance in 76 clinical H. pylori isolates were simultaneously assessed using agar dilution and broth microdilution methods. The correlation between the minimum inhibitory concentrations (MICs) obtained by the 2 methods was assessed by means of linear regression analysis.

RESULTS

The correlation between the MICs determined by broth microdilution method and agar dilution method was good for both CLR (r = 0.966) and LEV (r = 0.959). The susceptibility agreement between the 2 methods was 100% for CLR and 96.1% for LEV. Using the broth microdilution method, the false resistance was found in 3.9% (3 of 76) strains for LEV susceptibility testing. No false susceptibility was found for either CLR or LEV, and no false resistance was found for susceptibility testing of CLR.

CONCLUSIONS

The broth microdilution method is suitable for routine susceptibility testing of clinical H. pylori isolates.

Rifabutin as salvage therapy for Helicobacter pylori eradication: Cornerstones and novelties

When several Helicobacter pylori eradication treatments fail, guidelines recommend a cultured guided approach; however, culture is not widely available. Therefore, a rifabutin based regimen could be the best solution. Rifabutin indeed shows a low rate of antibiotic resistance. Rifabutin is generally used in combination with amoxicillin in a triple therapy, with eradication rates about 80% in third-line regimens. The ideal duration of this therapy should range between 10 and 12 d. Combinations with antibiotics other than amoxicillin have demonstrated even better results, such as vonoprazan, which is a type of novel acid suppressor drug. Finally, a new formulation of triple therapy in a single capsule is under investigation, which is a field that deserves further investigation. Some notes of caution about rifabutin should be mentioned. This drug is used to treat tuberculosis or atypical mycobacteria; therefore, before starting a rifabutin-based eradication regimen, Mycobacterium tuberculosis infection should be thoroughly tested, since its use could promote the development of antibiotic resistance, thus affecting its effectiveness against Koch’s bacillus. Additionally, some serious side effects must be evaluated before starting any rifabutin-based therapy. Adverse effects include fever, nausea, vomiting and bone marrow suppression. For this reason, full blood count surveillance is required.

Detection and Treatment of Helicobacter pylori: Problems and Advances

Helicobacter pylori (H. pylori) infection is chronic and etiologically linked to gastric cancer (GC) derived from gastric epithelium. The potential mechanism is complex, covering chronic inflammation, epithelial senescence, NF-κB activation, the cytotoxin-associated gene A protein translocation, and related abnormal signaling pathways. In clinical practice, the test-and-treat strategy, endoscopy-based strategy, and (family-based) screen-and-treat strategy are recommended to detect H. pylori and prevent GC. It has been demonstrated that the decreasing annual incidence of GC is largely attributable to the management of H. pylori. This study reviews the current clinical practice of H. pylori on the detection and eradication, alternative treatment strategies, and related problems and advances, and hopes to contribute to the better clinical management of H. pylori.

Biomaterials for Helicobacter pylori therapy: therapeutic potential and future perspectives

Helicobacter pylori (H. pylori) is the main cause of gastric adenocarcinoma. However, the traditional antibiotic treatment of H. pylori is limited due to increased antibiotic resistance and low efficacy; low drug delivery efficiency and difficulties in eradicating H. pylori that is present intracellularly or in biofilms cause further setbacks. Biomaterials that can protect drugs against stomach acid, target lesions, control drug release, destroy biofilms, and exhibit unique antibacterial mechanisms and excellent biocompatibility have emerged as attractive tools for H. pylori eradication, particularly for drug-resistant strains. Herein, we review the virulence mechanisms, current drug treatments, and antibiotic resistance of H. pylori strains. Furthermore, recent advances in the development of biomaterials, including nanoparticles (such as lipid-based nanoparticles, polymeric nanoparticles, and inorganic nanoparticles), microspheres, and hydrogels, for effective and precise therapy of H. pylori and different types of therapeutic mechanisms, as well as future perspectives, have also been summarized.

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

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

Efficacy and safety of low-dose rifabutin-based 7-day triple therapy as a third- or later-line Helicobacter pylori eradication regimen

BACKGROUND

Rifabutin-based regimens are used as rescue therapy for refractory Helicobacter pylori infection; however, the duration for which treatment is required and side effects are concerning. This study assessed the efficacy and safety of 7-day rifabutin, amoxicillin, and vonoprazan triple therapy as third- or later-line treatment for H. pylori infection.

MATERIALS AND METHODS

Patients who did not respond to second-line therapy were enrolled. After H. pylori infection was confirmed with the culture method, the patients received rifabutin-containing triple therapy (20 mg vonoprazan b.i.d., 500 mg amoxicillin q.i.d., and 150 mg rifabutin q.d.) for 7 days. Twelve weeks after the eradication therapy, successful eradication was confirmed using a ¹³ C urea breath test or the H. pylori stool antigen test. The results obtained from our previous study that reported a 10-day or 14-day esomeprazole based rifabutin-containing triple therapy as a third- or fourth-line rescue therapy treated patients were used as historical control. We determined the minimum inhibitory concentrations of amoxicillin and rifabutin. We also evaluated whether the patients were positive for the mutation of the rpoB gene.

RESULTS

Intention-to-treat and per-protocol analyses showed that our regimen resulted in a high eradication rate (91.2%, 95% CI: 84%-99% and 92.7%, 95% CI: 86%-100%, respectively). Adverse events occurred in 31.6% of the patients, and two patients discontinued the therapy.

CONCLUSIONS

This is the first study to evaluate the efficacy and safety of a 7-day low-dose rifabutin-based triple therapy with vonoprazan and amoxicillin. Our results suggest that our regimen was effective and safe as a third- or later-line H. pylori eradication regimen. To clarify what component in this regimen are critical, subsequent studies using a factorial design (comparing vonoprazan-amoxicillin dual therapy vs. vonoprazan-rifabutin triple therapy) will be needed.

Potassium-Competitive Acid Blocker and Proton Pump Inhibitor-Based Regimens for First-Line Helicobacter pylori Eradication: A Network Meta-Analysis

Background and Aims

Effective acid suppression is a crucial component of Helicobacter pylori (H. pylori) eradication regimens. Approved treatments include dual, triple, and quadruple therapies composed of certain antibiotics in combination with proton pump inhibitors (PPIs). Vonoprazan, a potassium-competitive acid blocker, provides more potent and durable acid suppression than PPIs. We compared the efficacy of vonoprazan-based therapies vs approved standard regimens using new evidence from the phase 3 pHalconHP trial in North America and Europe.

Methods

Studies reporting first-line H. pylori eradication rates from empiric treatment with Food and Drug Administration-approved therapies and vonoprazan-containing therapies were identified via bibliographic searches of systematic literature reviews and a subsequent MEDLINE/Embase search using index terms for H. pylori and eradication. Randomized controlled trials comparing 2 or more relevant comparators were included in Bayesian network meta-analyses for grouped and distinct therapies.

Results

Twenty-three distinct regimens from 42 trials including 12,773 patients were identified. Vonoprazan-based triple therapy showed the highest relative efficacy (odds ratio: 2.73, 95% credible interval 2.11, 3.54) and 72.1% probability of being the best. North American, Western, and global scenarios were largely consistent. Vonoprazan-based therapies demonstrated higher odds of H. pylori eradication than each PPI-based triple therapy. Furthermore, vonoprazan-based triple therapy was superior to bismuth subcitrate quadruple therapy (odds ratio: 1.60, 95% credible interval: 1.07, 2.38).

Conclusion

Vonoprazan-based eradication regimens represent novel treatments for H. pylori infection on a global scale, offering efficacy that, in this analysis, is superior to PPI-based triple therapy and comparable or better than bismuth quadruple therapy.

Need for standardization and harmonization of Helicobacter pylori antimicrobial susceptibility testing

BACKGROUND AND AIMS

As with other infectious diseases, Helicobacter pylori eradication regimens should be guided by susceptibility testing to achieve excellent success rate, especially in the era of high antibiotic resistance. However, susceptibility testing for H. pylori is rarely performed, which can be partly ascribed to the current lack of standardization of testing methods and the lack of unified consensus on the antibiotic resistance breakpoints. The aim of this review was to call for an international consensus on standardization and harmonization of H. pylori susceptibility testing.

METHODS

We summarize and compare the advantages and disadvantages of four different phenotypic antimicrobial susceptibility testing (AST) methods (agar dilution, E-test, disk diffusion, and broth microdilution) and the molecular susceptibility testing method for H. pylori.

RESULTS

The standard phenotypic testing methods and the molecular testing methods have their own advantages and disadvantages. Compared to the standard phenotypic methods, the molecular testing method does not require successful H. pylori culture, and therefore, is much more rapid and convenient for clinical use. However, the currently available molecular testing method is only suitable for detecting clarithromycin and quinolone susceptibility profiles in H. pylori. Although the standard AST is time-consuming, it is currently the only way to test the susceptibility of H. pylori to all the commonly used antibiotics.

CONCLUSION

To make H. pylori susceptibility testing become a clinical routine, an international consensus on standardization and harmonization of H. pylori AST is needed. Future efforts are needed for optimizing broth culture of H. pylori, and developing commercial AST plates for achieving high throughput and automated susceptibility testing for H. pylori.

Helicobacter pylori infection treatment in the United States: clinical consequences and costs of eradication treatment failure

INTRODUCTION

Helicobacter pylori (Hp) is causal in benign and malignant gastrointestinal diseases. Accordingly, current guidelines recommend Hp eradication in patients with active infection. Unfortunately, treatment failure is common, exposing patients to complications associated with persistent Hp infection and consequences of repeated treatment, including promotion of antibiotic resistance. In the United States (US), data regarding eradication rates with available therapies are limited. Moreover, the clinical and economic burden of eradication treatment failure have not been thoroughly described.

AREAS COVERED

We aimed to characterize Hp eradication rates and the clinical consequences and associated costs of persistent Hp infection among US adults. We conducted focused literature reviews using initial searches in Embase, MEDLINE, and Cochrane Database of Systematic Reviews via Ovid followed by manual searches to identify relevant publications.

EXPERT OPINION

Hp eradication rates were suboptimal, with most studies reporting rates ≤80% with clarithromycin-based triple therapy and bismuth quadruple therapy. There was direct evidence supporting numerous benefits of successful Hp eradication, including decreased risk of recurrent or complicated peptic disease and non-cardia gastric cancer. Cost benefits of eradication were related to mitigation of conditions associated with persistent Hp infection, (e.g. complicated peptic ulcer disease, and gastric cancer) which altogether exceed US$5.3 billion.

Experience with Rifabutin-Containing Therapy in 500 Patients from the European Registry on Helicobacter pylori Management (Hp-EuReg)

BACKGROUND

First-line Helicobacter pylori (H. pylori) treatments have been relatively well evaluated; however, it remains necessary to identify the most effective rescue treatments. Our aim was to assess the effectiveness and safety of H. pylori regimens containing rifabutin.

METHODS

International multicentre prospective non-interventional European Registry on H. pylori Management (Hp-EuReg). Patients treated with rifabutin were registered in AEG-REDCap e-CRF from 2013 to 2021. Modified intention-to-treat and per-protocol analyses were performed. Data were subject to quality control.

RESULTS

Overall, 500 patients included in the Hp-EuReg were treated with rifabutin (mean age 52 years, 72% female, 63% with dyspepsia, 4% with peptic ulcer). Culture was performed in 63% of cases: dual resistance (to both clarithromycin and metronidazole) was reported in 46% of the cases, and triple resistance (to clarithromycin, metronidazole, and levofloxacin) in 39%. In 87% of cases rifabutin was utilised as part of a triple therapy together with amoxicillin and a proton-pump-inhibitor, and in an additional 6% of the patients, bismuth was added to this triple regimen. Rifabutin was mainly used in second-line (32%), third-line (25%), and fourth-line (27%) regimens, achieving overall 78%, 80% and 66% effectiveness by modified intention-to-treat, respectively. Compliance with treatment was 89%. At least one adverse event was registered in 26% of the patients (most frequently nausea), and one serious adverse event (0.2%) was reported in one patient with leukopenia and thrombocytopenia with fever requiring hospitalisation.

CONCLUSION

Rifabutin-containing therapy represents an effective and safe strategy after one or even several failures of H. pylori eradication treatment.

Diagnosis and Treatment of Helicobacter pylori Infection

The last 5 years have seen major shifts in defining whom to test and how to treat Helicobacter pylori infection. Peptic ulcer has changed from a chronic disease to a one-off condition, and countries with a high incidence of gastric cancer have begun implementing population-wide screening and treatment. A proactive approach to testing and treatment of H. pylori is now recommended, including outreach to family members of individuals diagnosed with active infection as well as high-risk local populations such as immigrants from high-risk countries. Increasing antimicrobial resistance has resulted in an overall decline in treatment success, causing a rethinking of the approach to development of treatment guidelines as well as the need to adopt the principles of antibiotic usage and antimicrobial stewardship. Required changes include abandoning empiric use of clarithromycin, metronidazole, and levofloxacin triple therapies. Here, we discuss these transformations and give guidance regarding testing and use of therapies that are effective when given empirically.

Pitfalls of Physician-Directed Treatment of Helicobacter pylori: Results from Two Phase 3 Clinical Trials and Real-World Prescribing Data

BACKGROUND

Helicobacter pylori (H. pylori) infects ~ 35% of Americans and can lead to serious sequelae if left untreated. Growing evidence indicates that clarithromycin-based therapies (CBT) are becoming increasingly ineffective for treating H. pylori infection. RHB-105 was approved by the US Food and Drug Administration in 2019 for the treatment of H. pylori infection in adults.

AIMS

The primary aim of this study was to assess prescribing patterns and associated cure rates of physician-directed therapy for subjects with persistent H. pylori infection after participation in one of two Phase 3 clinical trials (ERADICATE Hp and ERADICATE Hp2).

METHODS

We reviewed study reports to identify specific physician-directed regimens selected for subjects whose H. pylori infection was not eradicated. We also conducted a CYP2C19 genotype analysis of subjects who were prescribed CBT. Finally, we analyzed real-world H. pylori retail prescription data and compared these with to the physician-directed therapies in the clinical trials studies.

RESULTS

Following ERADICATE Hp, CBT was prescribed for 27/31 (87%) subjects achieving a 59.3% cure rate. Following ERADICATE Hp2, CBT was prescribed for 48/94 (51%) subjects achieving a 60.4% cure rate. Rapid CYP2C19 metabolizers (2/11) had a cure rate of 18.2% with CBT. Real-world prescription data from IQVIA showed more than 80% of prescriptions for H. pylori infection were for CBT.

CONCLUSIONS

Rates of CBT use persist despite sub-optimal eradication rates. Since RHB-105 does not contain clarithromycin, it can be prescribed first-line without concerns about clarithromycin resistance or CYP2C19 status. NCT03198507 & NCT01980095.

Helicobacter pylori diagnosis and therapy in the era of antimicrobial stewardship

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

Lessons From a Quality Improvement Project to Standardize the Process of Gastric Biopsy Culture for Helicobacter pylori

Despite expert recommendations, clinician's adherence to pediatric societal clinical practice guidelines is variable, particularly with respect to the use of gastric biopsy culture in the initial diagnosis of Helicobacter pylori infection. In addition, the implementation of routine use of gastric biopsy culture has been challenging with several factors affecting the rate of successful primary H pylori culture.

Methods

We conducted a quality improvement (QI) project with the aims of increasing the rate of successful primary culture. The QI project involved educational efforts among our gastroenterologists, endoscopy suite personnel, and laboratory personnel. We compared the frequency of gastric biopsy culture sent in patients with international classification of diseases 9th revision code 041.86, and 10th revision codes B96.81 evaluated by pediatric gastroenterologists at Boston Children's Hospital during the 9 months before the QI intervention (February 1, 2019 to October 31, 2019) and 9 months after the QI intervention (November 1 2019 to July 31 2020). We also compared the rate of culture growth in patients with positive histology (culture positivity), and antimicrobial susceptibilities before and after November 1, 2019.

Results

We observed an increased frequency of gastric biopsy acquisition by any gastroenterologist, obtained in 39% (28 of 71) preintervention patients compared with 67% (36 of 54) intervention patients (P = 0.004). There was an increase in the percentage of culture positivity across study periods from 21% (3 of 14) preintervention to 45% (5 of 11) postintervention (P = 0.39; 95% confidence interval, 0.64-7.00).

Conclusion

Educational initiatives and collaborative work with staff physicians, endoscopy personnel, and hospital laboratory appear to be effective tools to increase usage of gastric biopsy culture as a diagnostic tool for H pylori infection and to increase culture positivity. Improving the surveillance of local resistance rates will improve the selection of the most effective primary treatment in specific geographic areas.

Comparison of Culture With Antibiogram to Next-Generation Sequencing Using Bacterial Isolates and Formalin-Fixed, Paraffin-Embedded Gastric Biopsies

BACKGROUND & AIMS

The decline in Helicobacter pylori cure rates emphasizes the need for readily available methods to determine antimicrobial susceptibility. Our aim was to compare targeted next-generation sequencing (NGS) and culture-based H pylori susceptibility testing using clinical isolates and paired formalin-fixed, paraffin-embedded (FFPE) gastric biopsies.

METHODS

H pylori isolates and FFPE tissues were tested for susceptibility to amoxicillin, clarithromycin, metronidazole, levofloxacin, tetracycline, and rifabutin using agar dilution and NGS targeted to 23S rRNA, gyrA, 16S rRNA, pbp1, rpoB and rdxA. Agreement was quantified using κ statistics.

RESULTS

Paired comparisons included 170 isolates and FFPE tissue for amoxicillin, clarithromycin, metronidazole, and rifabutin and 57 isolates and FFPE tissue for levofloxacin and tetracycline. Agreement between agar dilution and NGS from culture isolates was very good for clarithromycin (κ = 0.90012), good for levofloxacin (κ = 0.78161) and fair for metronidazole (κ = 0.55880), and amoxicillin (κ = 0.21400). Only 1 isolate was resistant to tetracycline (culture) and 1 to rifabutin (NGS). Comparison of NGS from tissue blocks and agar dilution from isolates from the same stomachs demonstrated good accuracy to predict resistance for clarithromycin (94.1%), amoxicillin (95.9%), metronidazole (77%), levofloxacin (87.7%), and tetracycline (98.2%). Lack of resistance precluded comparisons for tetracycline and rifabutin.

CONCLUSIONS

Compared with agar dilution, NGS reliably determined resistance to clarithromycin, levofloxacin, rifabutin, and tetracycline from clinical isolates and formalin-fixed gastric tissue. Consistency was fair for metronidazole and amoxicillin. Culture-based testing can predict treatment outcomes with clarithromycin and levofloxacin. Studies are needed to compare the relative ability of both methods to predict treatment outcomes for other antibiotics.

Evaluating treatments with rifabutin and amoxicillin for eradication of Helicobacter pylori infection in adults: a systematic review

INTRODUCTION

Helicobacter pylori causes dyspepsia, peptic ulcer, and gastric malignancies. Treatments for Helicobacter pylori are mostly empirical depending on regional antibiotic resistances and the patient's history and less frequently susceptibility guided. Helicobacter pylori has a low resistance to rifabutin and has been proposed as an alternative for third-line treatment and beyond but recently has also gained attention for use as first- and second-line treatment.

AREAS COVERED

In this review, the authors systematically searched medical databases in order to present the current eradication rates for any treatment based on the two antibiotics, rifabutin and amoxicillin with a potent acid inhibitor. They also assessed the safety and tolerance of all the relative regimens.

EXPERT OPINION

Treatment with a rifabutin- and amoxicillin-containing regimen is a valuable option when treating difficult to eradicate Helicobacter pylori infections. Its efficacy is overall 71.4%, and it is not influenced by previous antibiotics, gender, smoking habits, and age. Its results were better when used as a first- or second-line treatment. In third-line therapy and beyond, eradication rates are lower. Adverse effects of all rifabutin regimens occurred in 23% of patients and were mostly mild with bone marrow suppression being very low and reversible.

Combinations of antibiotics and vonoprazan for the treatment of Helicobacter pylori infections-Exploratory study

BACKGROUND

Vonoprazan fumarate is a novel potassium-competitive acid blocker more effective in suppressing acid production than proton pump inhibitors (PPIs) and when combined with antibiotics has been used to eradicate Helicobacter pylori (H. pylori) infection. However, it has not yet been examined in an Australian setting. This study aimed to report on the efficacy and safety of vonoprazan-containing antibiotic combination therapies in the eradication of H. pylori.

METHODS

A single-center, exploratory, clinical review of patients 18 years or over, positive for H. pylori on Urea Breath Test (UBT), and/or histopathology who underwent a 10-day treatment of combination antibiotics plus vonoprazan between January 2017 and September 2019 was conducted. Eleven different combinations of antibiotics that included 2-5 different antibiotics predominantly amoxicillin, rifabutin, levofloxacin, furazolidone, nitazoxanide, and tetracycline were included. The eradication success was based on negative UBT results and/or histopathology results after the treatment. Descriptive statistics were summarized.

RESULTS

One hundred and fifty-three patients (Female n = 74, 48%) with a positive for H. pylori were treated with vonoprazan-containing antibiotic combination therapy during the study period. Of the 153 patients, 48 (31%) had previously failed a PPI-based H. pylori treatment. Follow-up was available for 66/153 (43%) patients. In those who completed follow-up, overall eradication was achieved in 97% (64/66) of patients. In the subgroup of patients treated for the first time, eradication was achieved in 100% (44/44). In those who had failed prior, non-vonoprazan-containing treatment, eradication was achieved in 91% (20/22) of patients.

CONCLUSIONS

Vonoprazan-containing antibiotic therapy is an effective H. pylori eradication treatment. It is capable of achieving 100% efficacy in patients treated for the first time and even 91% efficacy in patients with previous eradication failure. Subsequent studies utilizing a factorial design will be needed to optimize each regimen as most regimens contained more than two antibiotics.

The effect of previous eradication failure on antibiotic resistance of Helicobacter pylori: A retrospective study over 8 years in Beijing

BACKGROUND

Antibiotic resistance is the main cause of Helicobacter pylori (H. pylori) treatment failure. This study aimed to explore the characteristics of antibiotic resistance of H. pylori isolates in Beijing in the last 8 years and to estimate the impact of previous eradication failure on resistance patterns.

MATERIALS AND METHODS

This retrospective study included data from a single center in Beijing from 2013 to 2020. Antibiotic susceptibility of 365 clinical H. pylori isolates was tested for amoxicillin, clarithromycin, metronidazole, levofloxacin, moxifloxacin, and tetracycline. The characteristics of the included patients and their previous eradication history were collected. Primary and secondary resistance rates of H. pylori to the six antibiotics and the impact of previous eradication failure on antibiotic resistance patterns were analyzed.

RESULTS

The overall primary resistance rates of amoxicillin, clarithromycin, metronidazole, levofloxacin, moxifloxacin, and tetracycline were 0.7%, 55.2%, 68.0%, 49.7%, 64.5%, and 0%, with no significant increase during the observed period; while the secondary resistance rates were 3.2%, 96.7%, 90.7%, 93.1%, 80.0%, and 0%, respectively. The secondary resistance rate of clarithromycin (p < .001), metronidazole (p = .001), and levofloxacin (p < .001) significantly increased to 100% as the number of previous eradication therapies increased and exhibited a linear association. For strains naive to eradication, only 6.8% were susceptible to all the antibiotics, while 32.4% were single resistant, and 60.8% dual or multiple resistant. Clarithromycin+metronidazole+fluoroquinolone multiple resistance was the predominant pattern (0 course: 21.6%, 1 course: 37.5%, 2 courses: 56.1%, ≥3 courses: 71.1%; p < .001) for patients with treatment failure. The prevalence of dual or multiple-resistance patterns increased significantly as the number of previous therapies increased.

CONCLUSIONS

The prevalence of primary and secondary resistance rates of clarithromycin, metronidazole, moxifloxacin, and levofloxacin were high in Beijing. Multiple-resistance patterns were common after treatment failure. Resistance rates of amoxicillin and tetracycline remained low and stable.

The status and progress of first-line treatment against Helicobacter pylori infection: a review

Helicobacter pylori (HP) is a major causative agent of chronic gastritis and peptic ulcer. HP is also engaged in the development of gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma. It is an important pathogenic factor in various other systemic diseases, such as vitamin B12 deficiency, iron deficiency, and idiopathic thrombocytopenia. The current consensus is that unless there is a special reason, eradication therapy should be implemented whenever HP infection is found, and it is ideally successful the first time. International guidelines recommend that under certain conditions, treatment should be personalized based on drug susceptibility testing. However, drug susceptibility testing is often not available because it is expensive, time-consuming, and difficult to obtain living tissue. Each region has separately formulated guidelines or consensuses on empirical therapy. Owing to an increasing drug resistance rate in various places, the eradication rate of proton pump inhibitor (PPI) triple therapy and sequential therapy has been affected. These regimens are rarely used; the PPI triple especially has been abandoned in most areas. Currently, radical treatment regimens for HP involve bismuth-containing quadruple therapy and concomitant therapy. However, quadruple therapy has its own limitations, such as complex drug administration. To improve the effectiveness, safety, and compliance, many clinical studies have proposed useful modified regimens, which mainly include the modified bismuth-containing quadruple regimen, high-dose dual therapy, and vonoprazan-containing regimens. Studies have shown that these emerging regimens have acceptable eradication rates and safety, and are expected to become first-line treatments in empirical therapy. However, the problem of decline in the eradication rate caused by drug resistance has not been fundamentally solved. This review not only summarizes the effectiveness of mainstream regimens in the first-line treatment of HP infection with the currently increasing antibiotic resistance rates, but also summarizes the effectiveness and safety of various emerging treatment regimens.

Treatment Approach of Refractory Helicobacter pylori Infection: A Comprehensive Review

H. pylori is the most common infection in the world and is associated with gastrointestinal and extra-gastrointestinal manifestations, including peptic ulcer disease, gastrointestinal bleeding, and lymphoproliferative disorders. Despite being discovered less than half a century ago, antibiotic resistance, exacerbated by medication non-adherence and inefficacy of proton pump inhibitors, has grown substantially, explaining the rising incidence of refractory H. pylori infection. In this review, we discuss risk factors, treatment options, surveillance and follow-up, as well as emerging therapies for refractory H. pylori.

Rifabutin triple therapy for first-line and rescue treatment of Helicobacter pylori infection: A systematic review and meta-analysis

BACKGROUND AND AIM

Due to the increasing resistance of Helicobacter pylori, there is a need for novel antibiotic treatment protocols. We aimed to perform a systematic review and meta-analysis in order to determine the effectiveness and safety of rifabutin triple therapy for H. pylori infection.

METHODS

We performed a systematic review of prospective clinical trials with a treatment arm consisting of proton pump inhibitor, amoxicillin, and rifabutin and a meta-analysis of randomized controlled trials (RCTs).

RESULTS

Thirty-three prospective studies including 44 datasets were identified. Meta-analysis of four RCTs for rescue treatment found no difference between treatment groups (odds ratio [OR] 0.88, 95% confidence interval [CI] 0.437-1.791, I²  = 68.1%, P = 0.733). Only one RCT compared rifabutin therapy with control for first-line treatment of H. pylori infection (OR 3.78, 95% CI 2.44-5.87, P < 0.0001). Treatment was more likely to be successful in Asian versus non-Asian populations (81.0% vs 72.4%, P = 0.001) and when daily amoxicillin dose was ≥ 3000 mg or proton pump inhibitor dose was ≥ 80 mg or treatment duration was 14 days (80.6% vs 66.0%, P = 0.0001). The overall event rate for adverse effects was 24.8% (729/2937) (95% CI 0.23-0.26), and the pooled OR for adverse effects in the treatment versus control group was 0.93 (95% CI 0.50-1.75) (I²  = 79.76, P = 0.82).

CONCLUSION

Evidence for the effectiveness of rifabutin for the first-line treatment of H. pylori infection in adults is limited, and studies comparing rifabutin with conventional first-line treatments are lacking.

AGA Clinical Practice Update on the Management of Refractory Helicobacter pylori Infection: Expert Review

The purpose of this CPU Expert Review is to provide clinicians with guidance on the management of Helicobacter pylori after an initial attempt at eradication therapy fails, including best practice advice on specific regimen selection, and consideration of patient and systems factors that contribute to treatment efficacy. This Expert Review is not a formal systematic review, but is based upon a review of the literature to provide practical advice. No formal rating of the strength or quality of the evidence was carried out. Accordingly, a combination of available evidence and consensus-based expert opinion were used to develop these best practice advice statements.

Antibiotic Resistance of Helicobacter pylori Strains Isolated From Pediatric Patients in Southwest China

The number of antibiotics that are appropriate for Helicobacter pylori eradication in children is limited. Profiling regional or population-specific antibiotic resistance is essential in guiding the H. pylori eradication treatment in children. The aim of this study was to evaluate the antibiotic resistance in H. pylori strains isolated from children and adolescents in Southwest China. Gastric biopsies from 157 pediatric patients with or without previous H. pylori eradication treatment were collected for H. pylori culture. Susceptibility to amoxicillin (AML), clarithromycin (CLR), metronidazole (MTZ), levofloxacin (LEV), tetracycline (TET), furazolidone (FZD), and rifampicin (RIF) was determined by E-test or a disk diffusion assay. A total of 87 patients from three ethnic groups (Han/Tibetan/Yi) were H. pylori culture positive (55.4%). The overall resistance rates were 55.2% for CLR, 71.3% for MTZ, 60.9% for RIF, and 18.4% for LEV. No isolate was found to be resistant to AML, TET, and FZD. Among the 53 treatment-naïve pediatric patients, primary resistance rates to clarithromycin, metronidazole, levofloxacin, and rifampicin were 45.3, 73.6, 15.1, and 60.4%, respectively. Among the 34 treatment-experienced patients, secondary resistance rates to clarithromycin, metronidazole, levofloxacin, and rifampicin were 70.6, 67.6, 23.5, and 61.8%, respectively. Isolates exhibiting simultaneous resistance to clarithromycin and metronidazole were 28.3 and 52.9% among the treatment-naïve and treatment-experienced patients, respectively. In conclusion, among pediatric patients in Southwest China, resistance rates were high for clarithromycin, metronidazole, levofloxacin, and rifampicin, whereas nil resistance was found to amoxicillin, tetracycline, and furazolidone. Our data suggest that the standard clarithromycin-based triple therapy should be abandoned as empiric therapy, whereas the bismuth quadruple therapy (bismuth/PPI/amoxicillin/tetracycline) would be suitable as first-line empiric treatment regimen for this pediatric population. Tetracycline and furazolidone may be considered for treating refractory H. pylori infections in adolescent patients.

Recent developments in antimicrobial therapy for gastrointestinal infections

PURPOSE OF REVIEW

This focused, narrative review summarizes human clinical trial data for direct-acting antimicrobials in development for the treatment of gastrointestinal infections that were published in the past 18 months (1 January 2019 to 30 June 2020).

RECENT FINDINGS

Antimicrobial agents for Clostridioides difficile infection (n = 6), cryptosporidiosis (n = 1), cytomegalovirus infection (n = 3) and Helicobacter pylori infection (n = 1) have completed and/or are undergoing human clinical trials.

SUMMARY

Although this review highlights significant advances in four disease states, many common gastrointestinal pathogens have no antimicrobials in human clinical trials, emphasizing the need for continued prioritization in this field of study.

Rifabutin for the Treatment of Helicobacter Pylori Infection: A Review

Nowadays, apart from having to know first-line Helicobacter pylori eradication regimens well, we must also be prepared to face treatment failures. The aim of this review is to summarize the role of rifabutin in the management of H. pylori infection. Bibliographical searches were performed in PubMed. Data on resistance and efficacy of rifabutin-containing regimens on H. pylori eradication were meta-analyzed. Mean H. pylori rifabutin resistance rate (39 studies, including 9721 patients) was 0.13%; when studies only including patients naïve to H. pylori eradication treatment were considered, this figure was even lower (0.07%). Mean H. pylori eradication rate (by intention-to-treat) with rifabutin-containing regimens (3052 patients) was 73%. Respective cure rates for second-, third-, fourth- and fifth-line therapies, were 79%, 69%, 69% and 72%. Most studies administered rifabutin 300 mg/day, which seemed to be more effective than 150 mg/day. The ideal length of treatment remains unclear, but 10–12-day regimens are generally recommended. Adverse events to rifabutin treatment in H. pylori studies were relatively infrequent (15%), and severe adverse events were exceptional (myelotoxicity was the most significant, although always reversible). In summary, rifabutin-containing therapy represents an encouraging strategy generally restricted, at present, to patients where previous (usually multiple) eradication regimens have failed.

Efficacy and safety of bismuth-containing quadruple treatment and concomitant treatment for first-line Helicobacter pylori eradication: A systematic review and meta-analysis

Bismuth-containing quadruple treatment (BQT) and concomitant treatment (CT) were recommended as alternative first-line treatments of Helicobacter pylori (H. Pylori). A meta-analysis was performed to evaluate the cure rates and compare efficacy and safety of BQT and CT for H. Pylori eradication. PubMed, Cochrane Library, and Embase databases were searched on June 16, 2020. Meta-analysis, sensitivity analysis, and subgroup analysis were conducted by Review Manager 5.3 and Stata 11.0. Ten studies were collected. We found no difference of cure rate between BQT and CT in intention-to-treat (ITT) analysis (84.6% vs. 82.9%, OR = 1.14, 95% CI: 0.94-1.38; P = 0.19) and marginally statistical difference in per-protocol (PP) analysis (92.4% vs 90.1%, OR = 1.32, 95% CI: 1.00-1.73; P = 0.05). Based on the results of subgroup analyses, we found statistical difference of eradication rate between BQT and CT (amoxicillin + clarithromycin + metronidazole + PPI treatment) according to PP analysis (94.3% vs. 91.5%, OR = 1.49, 95% CI:1.03-2.15; P = 0.03) and marginally statistical difference according to ITT analysis (87.5% vs. 84.6%, OR = 1.28, 95% CI:1.00-1.65; P = 0.05). BQT and CT may be both good treatment options for H. pylori infection. However, BQT was superior to current scheme of CT (amoxicillin + clarithromycin + metronidazole + PPI treatment) in subgroup analysis. It is very necessary to choose tailored therapy as an outstanding way to reduce the impact of antibiotic.

An update on current and advancing pharmacotherapy options for the treatment of H. pylori infection

Introduction: Eradication of Helicobacter pylori (H. pylori) becomes more challenging due to increasing antimicrobial resistance. Consequently, the performance of clarithromycin-containing triple therapies is now declining to unacceptable levels and should be abandoned unless a prior susceptibility test precludes clarithromycin resistance.Areas covered: This review summarizes updated evidence concerning new and advancing pharmacotherapy options for H. pylori eradication.Expert opinion: Due to the declining efficacy of legacy triple therapies, most guidelines recommend bismuth quadruple therapy as the best initial empiric treatment. Concomitant, sequential and hybrid therapies are remarkable bismuth-free quadruple options, provided that dual clarithromycin-metronidazole resistance is low. Levofloxacin-, rifabutin-, furazolidone- and sitafloxacin-containing regimens remain useful, particularly as salvage options. To eradicate H. pylori in line with the rules of antibiotic stewardship, susceptibility-guided treatment appears as the ideal approach. However, the feasibility and cost-effectiveness of universal pre-treatment susceptibility testing warrants further evaluation. Molecular testing methods promise convenient characterization of H. pylori antibiotic susceptibility. High-dose dual therapy (proton-pump-inhibitor plus amoxicillin) and vonoprazan, a more potent acid inhibitor that likely enhances the activity of amoxicillin, are promising alternatives that could decrease misuse of antibiotics. Addition of certain probiotics could somewhat increase the performance of H. pylori eradication regimens, while improving tolerability.