Our previous study included 119 Helicobacter pylori(H. pylori)-infected Chinese patients without previous eradication history who were randomized to low-or high-dose amoxicillin-vonoprazan regimens consisting of amoxicillin 1 gram either b.i.d. or t.i.d plus vonoprazan 20 mg b.i.d for 7 or 10 days. Neither 7-or 10-day VA dual therapy with either b.i.d. or t.i.d. amoxicillin achieved satisfied efficacy (i.e., <90%) when given as first-line treatment for H. pylori infection. Lacidophilin tablets have been reported to increase the eradication rate of H. pylori while reducing the incidence of adverse effects.This study evaluated the efficacy and safety of lacidophilin tablets in combination with amoxicillin-vonoprazan dual therapy for 10 days as first-line treatment for H. pylori in China.

This study was designed as a prospective, multi-centers, double-blind, randomized superiority clinical study and was conducted in accordance with the Declaration of Helsinki and the guidelines of the Consolidated Standards of Reporting Trials.

Consecutive H. pylori-infected subjects ages from 18 to 70 without eradication history were recruited . H. pylori infection was confirmed by immunohistochemistry or urea breath test.

The H. pylori-infected subjects were randomly assigned to receive lacidophilin tablets or placebo in combination with amoxicillin-vonoprazan dual therapy for in a 1:1 allocation ratio, a randomization list was generated using Statistical Product Service Solutions (version 25.0).

The therapy consisted of 2400mg lacidophilin tablets or placebo three times daily, 1000 mg amoxicillin capsules three times daily and 20mg vonoprazan fumarate tablets twice daily for 10 days. The shape, taste, packaging, storage method and administration method of placebo are the same as lacidophilin tablets. Participants and investigators were blinded to the allocated treatment group.

At the start, the detailed demographics and characteristics of the subjects included in this study were recorded, including sex, age, nationality, height, weight, education status, dwelling area, history of smoking and alcohol, concomitant diseases and medication history. In addition, physical examinations and assessment of vital signs were performed. Gastric antrum and body biopsy of the included subjects were obtained during the endoscopy, which were followed by culture and susceptible test of antibiotics. Fecal sample was collected before eradication.

During (or after) treatment-emergent adverse events (TEAEs) and concomitant medication were recorded throughout the study, including bloating, nausea, vomiting, abdominal pain, diarrhea, constipation, skin rash, headache, hunger sensation and others. All TEAEs were divided into mild, moderate and severe, TEAEs leading to study drug discontinuation were also recorded. Fecal sample was collected after eradication.

The confirmation of H. pylori status was evaluated by 13C-urea breath test 4-8 weeks after treatment. H. pylori status was considered as negative or positive according to the instructions of the manufacturer. Oral and fecal sample was collected at the timepoint of recheck.

Inclusion Criteria:

• Consecutive H. pylori-infected subjects ages from 18 to 70 without eradication history

Exclusion Criteria:

• allergy to amoxicillin,vonoprazan or lacidophilin tablets;
• acute upper gastrointestinal bleeding, gastric cancer or other tumors, Zollinger-Ellison syndrome, history of gastric surgery;
• gastroscopy report showing or past medical history of significant esophagogastric disease, including gastric cancer, peptic ulcer, esophagitis, esophageal erosion.
• serious illness including neurological, cardiovascular, pulmonary, hepatic, renal, metabolic, gastrointestinal, urological, endocrinological or hematological disorders;
• pregnancy or breast feeding;
• proton pump inhibitors, antibiotics and probiotics use within one month;
• not willing to participate in the study.