High Efficacy of Levofloxacin-Dexlansoprazole-Based Quadruple Therapy as a First Line Treatment for Helicobacter pylori Eradication in Thailand

Helicobacter pylori (H. pylori), a gram-negative bacterium found on the luminal surface of the gastric epithelium, was first isolated in 1984 (Marshall and Warren, 1984). It induces chronic inflammation of the underlying mucosa resulting in the development of important upper gastrointestinal diseases such as gastritis, peptic ulcer diseases, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer (Rauws and Tytgat, 1990; Parsonnet et al., 1991; Bayerdorffer et al., 1995; Vilaichone and Mahachai, 2001). Moreover, a recent meta-analysis has shown that H. pylori eradication potentially reduces the incidence of gastric cancer, especially in high prevalence area of gastric cancer (Ford et al., 2014).


Introduction
Helicobacter pylori (H.pylori), a gram-negative bacterium found on the luminal surface of the gastric epithelium, was first isolated in 1984 (Marshall and Warren, 1984).It induces chronic inflammation of the underlying mucosa resulting in the development of important upper gastrointestinal diseases such as gastritis, peptic ulcer diseases, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer (Rauws and Tytgat, 1990;Parsonnet et al., 1991;Bayerdorffer et al., 1995;Vilaichone and Mahachai, 2001).Moreover, a recent meta-analysis has shown that H. pylori eradication potentially reduces the incidence of gastric cancer, especially in high prevalence area of gastric cancer (Ford et al., 2014).

High Efficacy of Levofloxacin-Dexlansoprazole-Based Quadruple Therapy as a First Line Treatment for Helicobacter pylori Eradication in Thailand
Hatainuch Prapitpaiboon 1 , Varocha Mahachai 2,3 , Ratha-Korn Vilaichone 1,3 * For years, H. pylori has been regarded as a difficultto-treat infection due to the bacterium's nature, and readily acquired resistance to commonly used antibiotics.Therefore, standard triple therapy with proton pump inhibitor (PPI), amoxicillin and clarithromycin is no longer recommended as an empiric choice in most countries (Chey and Wong, 2007;Mahachai et al., 2011).Levofloxacin-based triple therapy for H. pylori eradication has been shown to increase cure rate with minimal side effects.However, levofloxacin-based triple therapy provided excellent results only in levofloxacin sensitivity (Antos et al., 2006).Interestingly, recent studies have demonstrated the positive effect of adding bismuth salt to levofloxacin-based triple therapy for H. pylori eradication, especially in levofloxacin resistance (Liao et al., 2013).
We conduct this study for searching an optimal combination of drugs and duration for first line H. pylori eradication in Thailand.We reported a prospective randomized trial evaluating H. pylori eradication by using levofloxacin-dexlansoprazole based quadruple therapy for 7-or 14-day.The effects of CYP2C19 genotype and antibiotic resistance were also examined.

Patients
Eligible patients age 18-75 years who underwent gastroscopic examination at Thammasat University Hospital, for dyspeptic symptoms between June 2014 and December 2014 were enrolled.After the endoscopy, those with diagnosis of non-ulcer dyspepsia, which was established during gastroscopy with normal finding or mild gastritis, were considered for entry in this study.Exclusion criteria included patients with a history of prior H. pylori eradication, previous gastric surgery, pregnancy, lactation, major systemic diseases, cardiovascular disease or administration of antibiotics, bismuth and PPI drugs in the preceding 4 weeks, or allergy to any one of the given medication in the regimens.All patients provided written informed consent.

The diagnosis of H. pylori infection
During the endoscopy, 4 biopsy samples from gastric antrum were obtained for rapid urease test, H. pylori culture and Epsilometer test (E-test) or GenoType ® HelicoDR, histological examination and CYP2C19 genotype.The results of CYP2C19 genotype testing were expressed as: rapid metabolizer (RM), intermediate metabolizer (IM) or poor metabolizer (PM).The presence of H. pylori was defined as: (1) positive H. pylori culture, or (2) positive tests (rapid urease test or histology).

Therapeutic regimens
Randomization was made by reference to a computergenerated list.The two different groups were given for 7-day or 14-day of 500mg levofloxacin once daily, 60mg dexlansoprazole twice daily, 1g long acting clarithromycin MR once daily, and 1048mg bismuth subsalicylate twice daily.

Post-therapy follow-up
At least 4 weeks after completion of therapy, 13C-urea breath test (UBT) was carried out in all patients to assess H. pylori eradication.Successful eradication was defined as a negative result from UBT. Pill count was conducted, and drug consumption over 90% was defined as good compliance.Side effects were assessed by personal interview using open-ended questions.The potential adverse events listed in the questionnaires were diarrhea, bitter taste, nausea, vomiting, palpitation, and skin rashes.New symptoms and exacerbation of pre-existing symptoms during the treatment period were considered to be therapy-related adverse events.Serious adverse events were defined as events that disturbed on daily activities.

Statistical analysis
We expected the eradication rate of levofloxacin-dexlansoprazole based quadruple therapy as an empiric therapy to be≥90%.Treatment success was pre-specified as a cure rate of≥95% (i.e.grade A) as described in previous studies (Graham et al., 2007), and failure as a cure rate of<90% per protocol.The demographic characteristics and frequencies of adverse effects were compared using chi-squared, Fisher's exact and student's t-test.The p-value<0.05was considered to be statistically significant.
The study was conducted according to the good clinical practice guideline, as well as the Declaration of Helsinki, and was approved by our local ethics committee.

Results
Total of 100 patients were included in this study, 44 men and 56 women with a mean age of 52.6 years.All 100 patients were randomized in to 2 groups as previously described.When compared, the patients with 7-day regimens were significantly younger and predominate with women.The baseline demographic data are shown in Table 1.One patient in each group discontinued treatment due to side effects.

Eradication of H. pylori infection
The results analyzed by both intention-to-treat (ITT) and per-protocol (PP) analyses were demonstrated as shown in Figure 1.The eradication rates by ITT analysis was 84% (42/50) with 7-day regimen and 96% (48/50) with 14-day regimen.PP eradication results were 85.7% (42/49) and 98% (48/49) with 7-and 14-day regimen, respectively.The cure rate was higher in 14-day regimen than those in 7-day regimen from both ITT and PP and could achieve cure rate of grade A (≥95%) as detail in Figure 1.
Antibiotic susceptibility tests were performed in 60 strains (37 from E-test and 23 from GenoType ® HelicoDR), which demonstrated 35.1% of metronidazole resistant, 18.3% of clarithromycin resistant and 13.5% of levofloxacin resistant strains as detail in Figure 2. CYP2C19 genotype tests were performed in 98 cases (49 from each 7-day and 14-day regimen).The CYP2C19 genotype tests revealed 54.1% RM, 34.7% IM and 11.2% PM.The prevalence of CYP2C19 genotype was similar in all groups of patients as in Table 2.

Adverse events
The common side effects include diarrhea, bitter taste, nausea, and vomiting which were found in all groups.Two patients (one from each study group) were withdrawn from treatment regimens because of side effects.Documented adverse reactions are shown in Table 3.None of subject experienced any major adverse event.

Discussion
At present, several epidemiological and experimental data support a pathological role between H. pylori and the development of gastric cancer (Basiri et al., 2014;Demirel et al., 2013;Rauws and Tytgat, 1990).It was estimated that H. pylori infection accounts for approximately 650,000 new cases of gastric cancer annually (de Martel et al., 2012).The eradication rate of H. pylori by standard triple therapy with clarithromycin-containing regimen was reported to be less than 70% in many countries worldwide, including Thailand (Vilaichone et al., 2006;Graham, 2009).It has been suggested that clarithromycincontaining regimens should be renounced as an empiric therapy especially in high clarithromycin resistance area.
Bismuth has long been known as an anti-H.pylori drug with minimal side effects.The previous study demonstrated that adding bismuth might be a good option to improve the eradication by standard triple therapy apart from increasing the dosage and duration of PPI (Srinarong et al., 2014).Several studies also demonstrated that administration of bismuth in quadruple therapy increased the eradication rate of H. pylori up to 90%, comparing to standard triple therapy (Ford et al., 2008;Fock et al., 2009).
Fluoroquinolones have been suggested as alternative drug but generally the results of fluoroquinolone triple therapy was less than 90% (Gisbert and Morena, 2006;Graham and Shiotani, 2012).In addition, recent studies have demonstrated that longer duration with 14-day fluoroquinolone triple therapy provided treatment success of 95% (Miehlke et al., 2011).
Our study supported this idea and also demonstrated high eradication rate (grade A) of H. pylori infection from 14-day levofloxacin-dexlansoprazole quadruple therapy as a first line treatment regardless of CYP2C19 genotype, clarithromycin or dual clarithromycin and metronidazole resistant strains.Only minor side effects were observed from this regimen.Furthermore, this 14-day regimen could achieve high cure rate with levofloxacin resistant strains.However, larger multi-center controlled studies are needed to confirm this hypothesis.
Figure 1.Eradication Rates According to Treatment Regimens