Efficacy analysis of empirical bismuth quadruple therapy, high-dose dual therapy, and resistance gene-based triple therapy as a first-line Helicobacter pylori eradication regimen – An open-label, randomized trial

1 Introduction

Helicobacter pylori is a gram-negative bacillus with a high infection rate and high pathogenicity. The prevalence of H. pylori infection in the Chinese population is nearly 50% [1], while it has slightly decreased in recent years, the rate is still high [2]. With the widespread use of antibiotics, the rate of antibiotic resistance in our population is also increasing [3]. At present, in the Chinese population, clarithromycin (resistance rate 20–40%), metronidazole (resistance rate 40–70%), and levofloxacin (resistance rate 20–40%) have high resistance rates, while the resistance rates of amoxicillin (0–5%), tetracycline (0–5%), and furazolidone (0–3%) are still low [4]. The eradication rate of standard triple therapy has been reduced to unacceptable levels (eradication rate <80%) as the therapy has been widely abandoned [5]. In the Maastricht V consensus report, it was proposed [6] that classical bismuth quadruple therapy is recommended as first-line eradication therapy in areas with high clarithromycin resistance (>15%). Since tetracycline is difficult to obtain in most parts of mainland China classical bismuth quadruple therapy cannot be widely used. Bismuth-containing quadruple therapy is recommended in the fifth national expert consensus on H. pylori infection in China [7], of which the most commonly used regimen with relatively fewer adverse reactions includes proton pump inhibitors (PPI) + amoxicillin + clarithromycin + bismuth. However, in our previous epidemiological survey, the resistance rate to clarithromycin reached 43.65% in the areas of Yangzhou, China. If such therapy was used, the eradication rate of H. pylori would inevitably be reduced and nearly half of the patients misused the antibiotics. The efficacy of clarithromycin-containing bismuth quadruple therapy has not been reported in adults in the areas of Yangzhou, China. In addition, there are many types of quadruple therapy drugs and patients have greater concerns about the occurrence of adverse drug events, which greatly affect medication compliance. Thus, we need to explore H. pylori eradication options that are more appropriate for the patients in the areas of Yangzhou, China.

When we analyzed the influential factors associated with H. pylori eradication failure, we found that antibiotic resistance was one of the most important causes of eradication failure [8]. As an infectious disease, H. pylori should theoretically be eradicated by selecting sensitive antibiotics based on susceptibility testing or local antibiotic resistance profiles. A study from Korea [9] aimed to evaluate the efficacy of drug susceptibility-based individualized therapy for first-line eradication of H. pylori in regions with high antibiotic resistance, with an intention-to-treat (ITT) eradication rate of 93.1% and a per-protocol (PP) eradication rate of 100.0%. Compared to sequential therapy, the eradication rate of drug susceptibility-based individualized therapy in the population was significantly higher. However, the difference in the antibiotic resistance spectrum in various regions, combined with the strict conditions of H. pylori culture and the low success rate of the sensitivity test, limits the selection of medication for H. pylori based on drug sensitivity tests [10]. With the rapid development of molecular biology techniques, antibiotic resistance in H. pylori can be obtained by genetic testing [11]. A multicenter prospective randomized controlled trial including 526 patients [12] was used to detect H. pylori infection and clarithromycin and levofloxacin resistance by a molecular detection method of genotype HelicoDR test, and sensitive antibiotic eradication was selected according to its drug resistance results. The individualized eradication efficiency was higher than that of traditional triple therapy. This molecular biological detection method greatly solves the bottleneck associated with the limited use of drug sensitivity tests in clinical practice.

In our population, the rate of resistance to amoxicillin is very low, and amoxicillin is widely used in infectious diseases [13]. Through an in-depth study of the bactericidal mechanism of amoxicillin, it was found that the antibacterial effect of amoxicillin on H. pylori is pH-dependent [14]. When gastric acid is fully inhibited and the pH level in the stomach can continue to reach greater than 6, amoxicillin can fully exploit its bactericidal effect on H. pylori; more sufficient gastric acid secretion inhibition yields a greater antibacterial efficacy of amoxicillin. A randomized controlled study [15] from a large sample compared the eradication safety of high-dose dual therapy with that of bismuth quadruple therapy. Modified dual therapy at a high dose and high administration frequency was equally effective, safer, and less costly than bismuth-containing quadruple therapy.

Currently, there is a lack of data regarding the appropriate H. pylori eradication regimen in the areas of Yangzhou, China. The aim of this study is to determine whether high-dose dual therapy and resistance-based triple therapy are superior to empirical bismuth quadruple therapy in terms of eradication rates and incidence of adverse events, and to assess the factors that may affect the success of eradication.

2 Materials and methods

2.3 Treatment regimens

The groups and intervention strategies of this study are shown in Figures 1 and 2, and patients who met the inclusion criteria were assigned to empirical bismuth quadruple therapy, high-dose dual therapy, and resistance gene-based triple therapy groups. Radical therapy for patients in the empirical bismuth quadruple therapy group (RACB regimen) was as follows: rabeprazole 20 mg, colloidal bismuth pectin 220 mg, amoxicillin 1,000 mg, and clarithromycin 500 mg all twice daily. Radical therapy for patients in the high-dose dual therapy group (RA regimen) was as follows: rabeprazole 20 mg and amoxicillin 750 mg four times daily. Lastly, radical therapy for patients in resistance gene-based triple therapy was as follows: if the patient was resistant to amoxicillin, rabeprazole 20 mg twice daily, furazolidone 100 mg twice daily, and tetracycline 500 mg three times daily (RFT regimen); if the patient was sensitive to amoxicillin and clarithromycin, rabeprazole 20 mg, amoxicillin 1,000 mg, and clarithromycin 500 mg all twice daily (RAC regimen); if the patient was sensitive to amoxicillin and metronidazole, but was resistant to clarithromycin, rabeprazole 20 mg twice daily, amoxicillin 1,000 mg twice daily, and metronidazole 400 mg three times daily (RAM regimen); if the patient was sensitive to amoxicillin and levofloxacin, but was resistant to clarithromycin and metronidazole, rabeprazole 20 mg twice daily, amoxicillin 1,000 mg twice daily, and levofloxacin 500 mg once daily (RAL regimen); and if the patient was sensitive to amoxicillin, but was resistant to clarithromycin, metronidazole, and levofloxacin, rabeprazole 20 mg, amoxicillin 1,000 mg, and furazolidone 100 mg, all twice daily (RAF regimen).

Figure 1

Study flowchart. ITT, intention-to-treat; mITT, modified intention-to-treat; PP, per-protocol.

Figure 2

Procedures for selecting sensitive antibiotic therapy based on H. pylori resistance gene test results. R, rabeprazole; A, amoxicillin; C, clarithromycin; M: metronidazole; L: levofloxacin; F: furazolidone; T, tetracycline.

The course of radical treatment in all three groups was 14 days, during which rabeprazole and colloidal bismuth pectin were administered half an hour before meals; amoxicillin, clarithromycin, metronidazole, levofloxacin, furazolidone, and tetracycline were administered half an hour after meals; and the drugs that needed to be taken four times daily were taken at bedtime in addition to the three meal times.

3 Results

3.2 Eradication rates

The primary outcome indicator of this study was to determine whether high-dose dual therapy and resistance gene-based triple therapy were superior to empirical bismuth quadruple therapy for H. pylori eradication. The eradication rate of resistance gene-based triple therapy was superior to that of empirical bismuth quadruple therapy (90.6 vs 77.6%, respectively, with a rate difference of 13.0% in ITT analysis; 94.9 vs 85.3%, respectively, with a rate difference of 9.6% in PP analysis) (Table 2), but the difference was not statistically significant both in the ITT analysis and PP analysis (Figure 3). Moreover, the eradication rate of the high-dose dual therapy group was superior to that of the empirical bismuth quadruple therapy group (84.7 vs 77.6%, respectively, with a rate difference of 7.1% in the ITT analysis; 91.0 vs 85.3%, respectively, with a rate difference of 5.7% in the PP analysis) (Table 2), and also the difference was not statistically significant (Figure 3). We concluded that high-dose dual therapy and resistance gene-based triple therapy could achieve eradication rates equivalent to the efficacy of empirical bismuth quadruple therapy.

Table 2

Comparison of eradication rates between three therapy groups

Eradication rate	Empirical bismuth quadruple therapy		High-dose dual therapy		Resistance gene-based triple therapy		P value
	n/N	95% CI (%)	n/N	95% CI (%)	n/N	95% CI (%)
ITT analysis	66/85(77.6%)	67.7–85.2	72/85(84.7%)	75.6–90.8	77/85(90.6%)	82.5–95.2	0.067
mITT analysis	66/80(82.5%)	72.7–89.3	72/81(88.9%)	80.2–94.0	77/83(92.8%)	85.1–96.6	0.124
PP analysis	64/75(85.3%)	75.6–91.6	71/78(91.0%)	82.6–95.6	75/79(94.9%)	87.7–98.0	0.124

CI, confidence interval; ITT, intention-to-treat; mITT, modified intention-to-treat; PP, per-protocol.

Figure 3

Comparison of eradication rates between three therapy groups.

3.4 Improvement of gastrointestinal symptoms after eradication therapy

The Global Overall Symptom questionnaires were given to participants before the H. pylori eradication therapy and after 1 month from the eradication therapy completed. The overall relief of gastrointestinal symptoms after eradication therapy was 81.3% (61/75) in patients treated with the empirical bismuth quadruple therapy, 89.7% (70/78) in patients treated with high-dose dual therapy, and 84.8% (67/79) in patients treated with the resistance gene-based triple therapy (Figure 4). Most patients’ discomfort symptoms improved after eradication of H. pylori, and there was no statistical difference between the three groups (P > 0.05).

Figure 4

Improvement in gastrointestinal symptoms after H. pylori eradication.

4 Discussion

H. pylori, an intragastric parasitic bacterium, has highly pathogenic characteristics [16–18]. China has a particularly high burden of H. pylori infections; the infection rate varies from region to region, and the prevalence of H. pylori infection in adults shows a decreasing trend in urban areas, which seems to be explained by differences in economic and social conditions [19,20]. However, in our previous epidemiological survey, we found that the infection rate of H. pylori in the areas of Yangzhou, China, reached 42.36% and belonged to areas with high infection rates. Recent surveillance reports on the trend of antimicrobial resistance in H. pylori have confirmed that the incidence of antibiotic resistance is increasing [4,21,22], resulting in a declining eradication rate, and that traditional triple therapy for H. pylori eradication is obsolete. Therefore, selection of an appropriate eradication therapy before the initial eradication of H. pylori is the focus of clinical attention. The consensus statement recommends [6,23,24] alternative first-line treatment options, including concomitant, sequential, mixed, and bismuth-containing quadruple therapy. Owing to the influence of clarithromycin and metronidazole resistance, non-bismuth quadruple therapy is not applicable in China. Bismuth-containing quadruple therapy is recommended as the first-line eradication regimen in the Fifth National Consensus Report on the Management of H. pylori infection in China [7]. It is also the most widely used radical regimen in clinical practice and can achieve a good eradication effect. However, there are many types of drugs for bismuth-containing quadruple therapy, and patients have greater concerns about the occurrence of adverse drug events which greatly affects medication compliance.

H. pylori is an infectious disease; theoretically, sensitive antibiotics should be selected for eradication therapy based on susceptibility testing or the local antibiotic resistance spectrum, which can avoid the abuse of antibiotics, reduce the types of drugs taken, and improve compliance [25,26]. However, the resistance rate of H. pylori to amoxicillin is still low, and high-dose dual therapy including PPI combined with amoxicillin has become an increasing concern in recent years. In a clinical study of dual therapy based on systematic review and meta-analysis, 12 randomized controlled studies were included, and the results showed that dual therapy with high-dose PPIs combined with amoxicillin, whether used for primary H. pylori eradication or salvage H. pylori eradication, could achieve better efficacy, with eradication rates of more than 90%, compared with various traditional radical therapies recommended by current mainstream clinical guidelines [27]. However, whether the above radical treatment options can achieve good results in rural areas of China has not been yet reported.

In this study, for the first time, we conducted a clinical study to determine whether high-dose dual therapy and resistance gene-based triple therapy were superior to empirical bismuth quadruple therapy for H. pylori eradication. The results showed that high-dose dual therapy and resistance gene-based triple therapy could achieve an eradication rate equivalent to empirical bismuth quadruple therapy. Due to the reduction in the types of drugs taken and precise radical cures, the adverse events of high-dose dual therapy were much lower than that of empirical bismuth quadruple therapy, and the adverse events of resistance gene-based triple therapy were equivalent to that of empirical bismuth quadruple therapy.

Actually, Swedish scholar Unge et al. [28] first used a PPI and amoxicillin dual regimen to eradicate H. pylori as early as 1989, and since then many scholars have attempted different doses and frequencies of PPI and amoxicillin, but consistent and satisfactory eradication rates have remained difficult to obtain. With the deepening of the study on the kinetics and pharmacodynamics of amoxicillin and PPI, the mechanism of the dual regimen has been gradually elucidated. First, H. pylori strains are not susceptible to amoxicillin resistance because simultaneous mutations in multiple penicillin-binding protein-related genes cause marked resistance to amoxicillin [29]. Second, amoxicillin is a time-dependent antibiotic. The bactericidal effect mainly depends on the percentage of time when the plasma concentration is higher than the minimum inhibitory concentration. The same amoxicillin dose prolonged the percentage of time when divided into multiple doses. Multiple doses can also increase the local drug concentration in the gastric juice. Oral administration of four times per day can result in a better bactericidal effect [30,31]. Third, amoxicillin exerts a bactericidal effect by inhibiting the formation of bacterial cell walls and is effective only when bacteria multiply actively. H. pylori multiplies actively when the intragastric pH is >6.0; thus, amoxicillin has the best bactericidal effect at this pH [5]. In addition, amoxicillin is easily destroyed in an acidic environment, and adequate inhibition of gastric acid is the key to its effective sterilization. As potent antacids, most PPIs are metabolized by CYP2C19 enzymes. When CYP2C19 is a moderate or poor metabolizer, PPI has a better acid-inhibitory effect. When the CYP2C19 gene is an extensive metabolizer, PPI is rapidly metabolized by the body, with a decreased acid-inhibitory effect and decreased H. pylori eradication efficacy. Oral PPI can achieve satisfactory acid suppression in CYP2C19 fast, moderate, and poor metabolizers four times daily [30]. The PPI selected for this study was rabeprazole, which is mainly metabolized by non-enzymatic pathways and is less affected by CYP2C19, which can achieve effective acid suppression.

Antibiotic resistance is one of the most important reasons for the failure of H. pylori eradication. Our previous epidemiological survey found that the resistance rates to clarithromycin, metronidazole, and levofloxacin in the areas of Yangzhou were 41.0, 38.8, and 44.9%, respectively. The rapid increase in drug resistance may be related to the characteristics of antibiotics that can easily induce drug resistance and their widespread irrational use in mainland China. Therefore, it is essential to understand antibiotic resistance in patients before eradication therapy. This study collected complete antibiotic resistance information for each patient, which was very helpful for us to comprehensively and accurately assess the causes and risk factors of radical cure failure. Our univariate and multivariate analyses of the factors affecting H. pylori eradication failure revealed that antibiotic resistance is one of the most important risk factors. In the resistance gene-based triple therapy, we avoided the use of resistant antibiotics and chose sensitive antibiotics to eradicate H. pylori. The results showed that a high eradication rate was achieved despite the use of triple therapy, which indicates that it is necessary to select sensitive antibiotics to eradicate H. pylori based on resistance results in the areas of China with a high resistance rate. This not only achieves a good eradication effect but also avoids secondary resistance due to antibiotic abuse in rural areas.

We found that most patients were able to alleviate their gastrointestinal discomfort after H. pylori eradication. First, almost all patients with H. pylori infection have chronic active gastritis, with high acidity in the stomach and a high inflammatory reaction. PPI can increase the pH of the stomach and reverse damage to the gastric mucosa, thus relieving gastric discomfort [32]. Second, microbiota dysbiosis can also cause gastrointestinal discomfort. In a study on the effect of H. pylori infection on the gastrointestinal microbiota [33], it was found that the microbial diversity of H. pylori-infected patients was significantly lower than that of H. pylori-uninfected patients, leading to a disruption of the flora, while successful eradication of H. pylori resulted in a transient decrease in microbial diversity due to the use of antibiotics. However, in the long term it significantly increased the microbiota of H. pylori-positive patients. The hypogastric microbial richness and homogeneity of the intragastric environment in H. pylori-positive patients were similar to those in H. pylori-negative patients.

Two notable points were observed in this study. First, we collected comprehensive and complete pre-radical baseline data, including demographic data and clinical characteristics, as well as information on antibiotic resistance in all patients, which increased the reliability of our findings. Second, we chose to collect gastric mucosal samples for molecular biological detection of H. pylori virulence genes and drug resistance genes, avoiding the drawbacks of low positive rates and long durations of drug sensitivity test cultures, which cause an inability to routinely perform detection in clinical practice. This method greatly shortened the time of antibiotic resistance results, allowed patients to begin treatment as early as possible, and enabled more extensive individualized diagnosis and treatment in clinical practice.

This study had some limitations. First, it was a prospective, single-center study with a small sample size. Therefore, a multicenter study with a lager sample size is needed to verify the effectiveness of eradication efficacy. Second, we did not detect genetic polymorphisms of CYP2C19 enzyme in patient blood samples. Although we selected rabeprazole, which is less affected by CYP2C19 enzymes, recent studies have shown that rabeprazole metabolism is also affected to some extent by the CYP2C19 genotype, which may have an impact on patients who choose high-dose dual therapy. At present, a potassium-competitive acid blocker (P-CAB) has been selected for H. pylori eradication. It is a novel antacid with reversible and competitive inhibitory effects on H⁺, K⁺ ATPase-mediated gastric acid secretion. It is considered to have an antacid effect on PPI and has potential benefits for H. pylori eradication. A meta-analysis of 1,599 H. pylori-positive patients showed no significant difference in eradication rates between P-CAB-based therapy and conventional PPI therapy in clarithromycin-sensitive patients. However, P-CAB-based therapy was more effective than PPI-based regimens in clarithromycin-resistant patients [34]. Therefore, P-CAB is expected to be a strong first-line therapy for H. pylori eradication in the future.

5 Conclusions

In summary, in patients with the first-time eradication of H. pylori infection in the areas of Yangzhou, high-dose dual therapy and resistance gene-based triple therapy achieved eradication rates and compliance equivalent to those of empirical bismuth quadruple therapy. Meanwhile high-dose dual therapy had lower rates of adverse events, fewer side effects, and greater safety. Eradication of H. pylori improves gastrointestinal discomfort in most patients with the infection. Eradication failure is primarily related to antibiotic resistance and poor compliance. Therefore, the appropriate regimen can be individualized for eradication therapy in clinical practice according to the patient’s resistance and tolerance to the drug.