Eradication of Helicobacter pylori (Hp) is necessary for preventing peptic ulcers and stomach cancer. The potassium-competitive acid blocker vonoprazan is a gastric acid secretion inhibitor that improves the success rate of Hp eradication through its immediate and persistent inhibition of acid excretion. In Japan, first-line treatment involves a regimen in which vonoprazan is combined with amoxicillin and clarithromycin, while second-line treatment involves vonoprazan combined with amoxicillin and metronidazole. However, in contrast to the vonoprazan-based first-line therapy, no studies have investigated the factors influencing the success of vonoprazan-based second-line therapy. In this study, we therefore aimed to investigate factors related to the success of vonoprazan-based second-line therapy. We analyzed the association between the success of Hp eradication and patient factors including metronidazole/amoxicillin minimal inhibitory concentrations (MICs). MICs were measured using the Hp isolated from each patient. A receiver operating characteristic (ROC) analysis was conducted to examine continuous variables and eradication success. We reviewed the records of 33 patients (age: 34-79 years, male/female: 22/11, and body mass index (BMI): 16.1-28.8 kg/m2) who underwent vonoprazan-based second-line therapy after failure of first-line therapy at seven Japanese facilities between October 2018 and June 2019. The eradication success rate was 81.8% (27/33). ROC analysis revealed an area under the curve and BMI cutoff value of 0.796 and 23.8 kg/m2, respectively. The eradication success rate was higher in patients with high BMI than in those with low BMI (p = 0.007). Our findings indicate that higher BMI is correlated with the success of vonoprazan-based second-line therapy.
Keywords: Helicobacter pylori infection; amoxicillin resistance; body mass index; eradication therapy; metronidazole resistance.