Management of antiviral drug resistance in chronic hepatitis B

Rescue antiviral treatment for patients with resistance to preexisting nucleos(t)ide analogues remains a clinical challenge. The correct choice of a first-line treatment of high potency and with a high genetic barrier to achieve sustained long-term suppression of viral replication provides the best chance of preventing treatment failure and the emergence of drug resistance. The management of treatment failure and drug resistance requires a precise and accurate clinical and virologic monitoring. Combination treatment with antiviral drugs that belong to different groups is associated with a lower chance of developing resistance to rescue drugs. To guarantee better control of viral replication in patients with drug resistance, the addition of another drug without a cross resistance profile should be given as early as possible, preferably at the time when genotypic resistance emerges. Long-term surveillance for treatment efficacy and possible emergence of drug resistance should be continued to prevent the emergence of multidrug-resistant strains.

A new look at anti-Helicobacter pylori therapy

With the rising prevalence of antimicrobial resistance,the treatment success of standard triple therapy has recently declined to unacceptable levels (i.e.,80% or less) in most countries.Therefore,several treatment regimens have emerged to cure Helicobacter pylori (H.pylori) infection.Novel first-line anti-H.pylori therapies in 2011 include sequential therapy,concomitant quadruple therapy,hybrid (dual-concomitant) therapy and bismuth-containing quadruple therapy.After the failure of standard triple therapy,a bismuth-containing quadruple therapy comprising a proton pump inhibitor (PPI),bismuth,tetracycline and metronidazole can be employed as rescue treatment.Recently,triple therapy combining a PPI,levofloxacin and amoxicillin has been proposed as an alternative to the standard rescue therapy.This salvage regimen can achieve a higher eradication rate than bismuth-containing quadruple therapy in some regions and has less adverse effects.The best second-line therapy for patients who fail to eradicate H.pylori with first-line therapies containing clarithromycin,amoxicillin and metronidazole is unclear.However,a levofloxacin-based triple therapy is an accepted rescue treatment.Most guidelines suggest that patients requiring third-line therapy should be referred to a medical center and treated according to the antibiotic susceptibility test.Nonetheless,an empirical therapy (such as levofloxacin-based or furazolidone-based therapies) can be employed to terminate H.pylori infection if antimicrobial sensitivity data are unavailable.

Quinolone-based first, second and third-line therapies for Helicobacter pylori

Helicobacter pylori （H. pylori ） is a very common bacterium that infects about 50% of the world population in urban areas and over 90% of people living in rural and developing countries. Fluoroquinolones, a class of antimicrobials, have been extensively used in eradic-ation regimens for H. pylori . Levofloxacin is the most commonly used, and in second-line regimens, is one of the most effective options. However, an increasing resistance rate of H. pylori to fuoroquinolones is being observed, that will likely affect their effectiveness in the near future. Other novel fluoroquinolone molecules, such as moxifoxacin, sitafoxacin, gatifoxacin and gemif-loxacin, have been proposed and showed encouraging results in vitro, although data on their clinical use are still limited. Further studies in large sample trials are needed to confirm their safety and efficacy profile in clinical practice.

Efficacy of a therapeutic strategy for eradication of Helicobacter pylori infection

AIM: To determine the efficacy of our therapeutic strategy for Helicobacter pylori (H. pylori) eradication and to identify predictive factors for successful eradication. METHODS: From April 2006 to June 2010, we retrospectively assessed 2428 consecutive patients (1025 men, 1403 women; mean age 55 years, age range 18-92 years) with gastric histology positive for H. pylori infection referred to our unit for 13-C urea breath test(UBT), after first-line therapy with proton pump inhibitor (PPI) b.i.d. + amoxicillin 1 g b.i.d. + clarithromycin 500 mg b.i.d. for 7 d. Patients who were still positive to UBT were recommended a second-line therapy (PPI b.i.d. + amoxicillin 1 g b.i.d. + tinidazole 500 mg b.i.d. for 14 d). Third choice treatment was empirical with PPI b.i.d. + amoxicillin 1 g b.i.d. + levofloxacin 250 mg b.i.d. for 14 d. RESULTS: Out of 614 patients, still H. pylori-positive after first-line therapy, only 326 and 19 patients respectively rechecked their H. pylori status by UBT after the suggested second and third-line regimens. "Per protocol" eradication rates for first, second and thirdline therapy were 74.7% (95% CI: 72.7%-76.4%), 85.3% (95% CI: 81.1%-89.1%) and 89.5% (95% CI: 74.9%-103%) respectively. The overall percentage of patients with H. pylori eradicated after two treatments was 97.8% (95% CI: 97.1%-98.4%), vs 99.9% (95% CI: 99.8%-100%) after three treatments. The study found that eradication therapy was most effective in patients with ulcer disease (P < 0.05, P = 0.028), especially in those with duodenal ulcer. Smoking habits did not significantly affect the eradication rate. CONCLUSION: First-line therapy with amoxicillin and clarithromycin produces an H. pylori eradication rate comparable or superior to other studies and secondline treatment can still be triple therapy with amoxicillin and tinidazole.

Efficacy and safety of high-dose esomeprazole–amoxicillin dual therapy for Helicobacter pylori rescue treatment:a multicenter,prospective,randomized,controlled trial

Background:High-dose dual therapy(HDDT)with proton pump inhibitors(PPIs)and amoxicillin has attracted widespread attention due to its favorable efficacy in eradicating Helicobacter pylori(H.pylori).This study aimed to compare the efficacy and safety of high-dose PPI-amoxicillin dual therapy and bismuth-containing quadruple therapy for H.pylori rescue treatment.Methods:This was a prospective,randomized,multicenter,non-inferiority trial.Patients recruited from eight centers who had failed previous treatment were randomly(1:1)allocated to two eradication groups:HDDT(esomeprazole 40 mg and amoxicillin 1000 mg three times daily;theHDDTgroup)and bismuth-containing quadruple therapy(esomeprazole 40 mg,bismuth potassium citrate 220 mg,and furazolidone 100 mg twice daily,combined with tetracycline 500 mg three times daily;the tetracycline,furazolidone,esomeprazole,and bismuth[TFEB]group)for 14 days.The primary endpoint was the H.pylori eradication rate.The secondary endpoints were adverse effects,symptom improvement rates,and patient compliance.Results:A total of 658 patients who met the criteria were enrolled in this study.The HDDT group achieved eradication rates of 75.4%(248/329),81.0%(248/306),and 81.3%(248/305)asdetermined by the intention-to-treat(ITT),modified intention-totreat(MITT),and per-protocol(PP)analyses,respectively.The eradication rates were similar to those in the TFEB group:78.1%(257/329),84.2%(257/305),and 85.1%(257/302).The lower 95%confidence interval boundary(9.19%in the ITT analysis,9.21%in the MITT analysis,and9.73%in the PP analysis)was greater than the predefined non-inferiority margin of10%,establishing a non-inferiority of the HDDT group vs.the TFEB group.The incidence of adverse events in the HDDT group was significantly lower than that in the TFEB group(11.1%vs.26.8%,P<0.001).Symptom improvement rates and patients’compliance were similar between the two groups.Conclusions:Fourteen-day HDDT is non-inferior to bismuth-containing quadruple therapy,with fewer adverse effects and good treatment compliance,suggesting HDDT as an alternative for H.pylori rescue treatment in the local region.Trial registration:Clinicaltrials.gov,NCT04678492.