In Chile, over 70% of adults are infected with Helicobacter pylori. This bacterium plays a key role in the development of a number of different diseases, gastric cancer in particular, so effective treatment is essential in clinical practice. It has been suggested that clarithromycin should not be used in any regimen when resistance to this antibiotic is >15%.1 Recently, a Chilean study showed a resistance rate to clarithromycin of 26%. In this scenario, the effectiveness of triple therapy (proton pump inhibitor [PPI], clarithromycin and amoxicillin) was only 63.8%.2 Despite that, a study in Chile involving 242 patients showed that 54.9% were treated with this therapy.3 The Spanish Consensus Conference has suggested a non-bismuth-based quadruple (concomitant) regimen (PPI, clarithromycin, amoxicillin and metronidazole) or a quadruple combination with bismuth (PPI, bismuth, tetracycline and metronidazole) as first-line treatment.1 Others have also recommended high-dose dual therapy as a first-line treatment for H. pylori eradication.3,4
We describe here the results on the effectiveness and safety of high-dose dual therapy from a retrospective, observational, descriptive study conducted at our centre from March to September 2022. The research protocol for the study was approved by the scientific ethics committee of the Universidad de los Andes [University of the Andes] with ID CEC2022071. We excluded all patients who had previously received any other H. pylori eradication regimen. All patients were treated with esomeprazole 40 mg three times a day (30 min before breakfast, lunch and evening meal) and amoxicillin 750 mg four times a day (with breakfast, lunch, afternoon tea and evening meal) for 14 days. The effectiveness of the dual therapy was evaluated with the H. pylori stool antigen test (Pylori-Strip test) which was performed six weeks after the end of eradication treatment and with at least 14 days without PPI treatment, with a negative result confirming the effectiveness of the regimen.
We included 77 patients with a median age of 52 (19–84), 54.5% male. Seventy-four patients completed the treatment. Effectiveness in the intention-to-treat group and in those who completed therapy was 87% and 90.5% respectively. Three patients discontinued treatment: two because of nausea and one because of urticaria. In the group that completed therapy, only one patient reported epigastric pain, this patient having a negative post-treatment eradication test. Fig. 1 shows a flow chart of the patients admitted to this study.
Our results show that high-dose dual therapy could be an alternative to quadruple (concomitant) therapy without bismuth or quadruple therapy with bismuth as a first-line treatment for H. pylori eradication. It is currently recommended that an eradication therapy be considered effective when it is capable of curing H. pylori infection in close to, or preferably more than, 90% of patients.1 In our cohort of patients the effectiveness in the intention-to-treat group and in those who completed therapy falls within this target. A meta-analysis including six studies with a total of 1677 patients infected with this bacterium showed that high-dose dual therapy is equally as effective as the bismuth-containing quadruple therapy (intention-to-treat: 84.6% vs 83.7%, relative risk (RR) = 1.01, 95% CI: 0.97–1.06, P = .49; per protocol: 88.4% vs 89.0%, RR = 1.00, 95% CI: 0.97–1.04, P = .99), with fewer side effects and better patient adherence to treatment.4 A Chilean study suggests that dual therapy, with an effectiveness of 88.6%, could be used as a first-line regimen in the eradication of H. pylori. However, only 35 patients (14.5% of the patients included in this study) were treated with the dual therapy regimen.3 Effective inhibition of gastric acidity is a factor in the action of amoxicillin. This antibiotic is unstable in an acidic gastric environment and inhibition of gastric acid with PPI improves the stability and bioavailability of amoxicillin in the stomach.4 When PPI are administered three to four times a day, a stable and sufficient gastric acidity suppression effect is obtained, which is independent of the CPY2C19 gene polymorphism. A recent meta-analysis including nine randomised controlled studies conducted in Asia shows that dual therapy with PPI and high-dose amoxicillin administered four times a day would have better efficacy and safety in eradicating H. pylori than other recommended guidelines.4 The dosage and type of PPI used in different studies have been variable4; we decided to use esomeprazole 40 mg three times a day, as reported by other authors.5 Prospective, randomised, controlled studies could define the best dose to use in high-dose dual therapy.
In conclusion, in this cohort of patients with H. pylori infection, high-dose dual therapy was shown to be effective and safe, raising the possibility that it could be used as first-line therapy here in Chile. Studies with larger numbers of patients should confirm these results.
FundingNo funding was received for this study.
Conflicts of interestThe authors declare that they have no conflicts of interest.
