Background: Helicobacter pylori infection occurs in children and adults worldwide. Standard triple therapy of omeprazole, amoxicillin and clarithromycin (OAC) may not be optimal.

Aim: To evaluate quadruple therapy with bismuth subcitrate potassium, metronidazole and tetracycline hydrochloride, given with omeprazole in H. pylori infected subjects who failed previous OAC eradication therapy.

Methods: This was a multicenter, open-label, single-arm, multinational study. Helicobacter pylori-positive subjects who had failed ≥1 previous course of OAC therapy with or without up to three supplemental treatments in the previous year. Subjects were treated for 10 days with a combination formulation containing bismuth subcitrate potassium 140 mg, tetracycline hydrochloride 125 mg, and metronidazole 125 mg, three capsules four times daily (q.d.s.), and omeprazole 20 mg twice daily (b.d.). The primary endpoint was H. pylori eradication rate defined as one negative (13) C-urea breath test ≥28 days post-treatment.

Results: Helicobacter pylori eradication rates ranged from 93.2% to 93.8% in the intent-to-treat population (n = 49), and from 94.7% to 95.0% in the PP population (n = 40). No clinically meaningful differences were observed when analysed by country. Metronidazole resistance was observed in 16/49 (32.7%) subjects and clarithromycin resistance in 31/49 (63.3%) subjects. Thirty-three subjects (67.3%) reported 87 adverse events, and only one (2%) discontinued the study for an adverse event.

Conclusions: A quadruple regimen of bismuth, metronidazole and tetracycline plus omeprazole produces a high eradication rate in subjects previously failing H. pylori eradication regimens. This bismuth-based regimen offers an effective option as rescue therapy.