High Dose Dual Therapy (HDDT) for Eradication of Helicobacter Pylori Infection

The investigators will performed a large-scale multi center trial to compare the efficacy of a high-dose dual therapy (HDDT) with that of standard therapies in treatment-naive (n = 300) patients with Hp infection. Consecutive symptomatic patients will be recruited in Israel and Spain when tested positive to Hp with serology and 13C urea breath test (13C-UBT) due to symptoms. Patients with gastric cancer, MALT lymphoma, and younger than 18 or older than 80 years old will be excluded. All patients will be naive to eradication therapy and will be randomized into one of three groups: Group 1: Nexium 40 mg and amoxicillin 1.5 gr twice daily for 14 days Group 2: Nexium 40 mg and doxycycline 200 mg twice a day Group 3: Triple therapy of Nexium 20 mg, clarythromycin 500 mg, and amoxicillin 1gr twice a day for 10 days (regular accepted treatment). All treatments will be stopped for a month and then 13CUBT will be repeated. The primary aim of the study is to assess eradication success, intentioned to treat and per protocol in the three treatment regimens. The secondary aim of the study is to assess the safety of high dose amoxicillin and doxycycline.