Clarithromycin-based triple therapy for non-resistant Helicobacter pylori infection - How long should it be given?

Background: We have previously reported mixed infection with wild-type (sen sitive) and mutant (resistant) Helicobacter pylori strains using a PCR-base d preferential home-duplex formation assay (PCR-PHFA) to detect gene mutati ons associated with clarithromycin resistance. Half of the cases with mixed infection were determined as sensitive by conventional MIC assessment and yet failed to respond to clarithromycin-based therapy. The aim of this stud y is to assess the efficacy of clarithromycin-based triple therapy in patie nts infected exclusively with wild-type strains as determined by PCR-PHFA. Methods: Ninety patients who had pure wild-type H. pylori infection were ra ndomly assigned to receive clarithromycin (200 mg b.i.d.). amoxicillin (500 mg q.i.d.) and lansoprazole (30 mg b.i.d.) for either 5 days or 7 days (n = 48 and n = 42. respectively). The outcome of eradication was assessed by [13C] urea breath lest. Results: Eradication was achieved in 36/38 (75%) ve rsus 39/42 (93%) by intention-to-treat analysis (P = 0.02), and in 36/45 (8 0%) versus 39/40 (98%) by per protocol analysis (P = 0.01), for the 5-day a nd 7-day protocols, respectively. Compliance and the incidence of untoward effects were similar in both groups. Conclusions: Seven-day administration is necessary and sufficient for the triple therapy with clarithromycin, amo xicillin and lansoprazole in patients with pure wild-type H. pylori infecti on.