Objectives No trial has compared non-bismuth quadruple ‘sequential’ and ‘concomitant’ regimens in settings with increasing clarithromycin rates. The study aims to compare the effectiveness and safety of these therapies for Helicobacter pylori treatment.

Design Prospective randomised clinical trial in 11 Spanish hospitals. Patients naïve to eradication therapy with non-investigated/functional dyspepsia or peptic ulcer disease were included. Randomised (1:1) to sequential (omeprazole (20 mg/12 h) and amoxicillin (1 g/12 h) for 5 days, followed by 5 days of omeprazole (20 mg/12 h), clarithromycin (500 mg/12 h) and metronidazole (500 mg/12 h)), or concomitant treatment (same drugs taken concomitantly for 10 days). Eradication was confirmed with ¹³C-urea breath test or histology 4 weeks after treatment. Adverse events (AEs) and compliance were evaluated with questionnaires and residual medication count.

Results 338 consecutive patients were randomised. Mean age was 47 years, 60% were women, 22% smokers and 20% had peptic ulcer. Concomitant and sequential eradication rates were, respectively, 87% vs 81% by intention-to-treat (p=0.15) and 91% vs 86% (p=0.131) per protocol. Respective compliances were 83% vs 82%. Treatment-emergent AEs were reported in 59% of patients (no differences found between treatments). AEs were mostly mild (60%), and average length was 6.1 days, causing discontinuation only in 12 patients. Multivariate analysis: ‘concomitant’ treatment showed an OR of 1.5 towards better eradication rate in a borderline significance CI (95% CI 0.9 to 2.8).

Conclusions Concomitant therapy led to a non-statistically significant advantage (5%) over sequential therapy, coming closer to 90% cure rates. Both therapies showed an acceptable safety profile.

ClincialTrials.gov: NCT01273441.