A seven-day regimen of low-dose amoxicillin and vonoprazan, a potassium-competitive acid blocker, is as effective at eradicating Helicobacter pylori as is vonoprazan-based triple therapy in regions with high clarithromycin resistance, researchers from Japan report. International guidelines recommend four-drug combination therapies containing two to three kinds of antibiotics for 10-14 days as first-line treatment for H. pylori in regions with high clarithromycin resistance in order to overcome its antimicrobial resistance. Among other disadvantages, such a regimen could fuel antibiotic resistance, the researchers write in Gut. Dual therapy including only a single antibiotic, on the other hand, would not be expected to contribute to H. pylori antibiotic resistance, according to Dr. Takuji Gotoda of Nihon University School of Medicine, in Tokyo, and colleagues. The team compared the efficacy and tolerability of dual therapy with vonoprazan plus low-dose amoxicillin vs triple therapy with vonoprazan, low-dose amoxicillin and clarithromycin, both for seven days, as the first-line treatment for H. pylori in an open-label trial including 335 patients. In the intention-to-treat analysis, the H. pylori-eradication rate was 84.5% in the dual-therapy group vs 89.2% in the triple-therapy group (P=0.2 for difference, P=0.07 for non-inferiority). Noninferiority criteria were, however, satisfied in the per-protocol analysis, where H. pylori-eradication rates were 87.1% with dual therapy vs 90.2% with triple therapy (P=0.02 for non-inferiority). In patients with clarithromycin-susceptible strains of H. pylori, eradication rates were significantly higher with triple therapy (95.1%) than with dual therapy (85.5%). In patients with clarithromycin-resistant strains, however, eradication rates were significantly higher in the dual-therapy group (92.3% vs. 76.2%). The rates of adverse events were similar between the dual-therapy (27.4%) and triple-therapy (30.5%) groups, and more than 90% of the events were mild. There were no severe adverse events. "Further studies should be demanded to develop vonoprazan-based dual therapy with proper adjustments and to establish new first-line H. pylori eradication treatments in the era of growing antimicrobial resistance," the researchers conclude. The study was funded by Nihon University School of Medicine. Dr. Gotoda, who has financial ties to vonoprazan's manufacturer, Takeda Pharmaceutical Company Limited, did not respond to a request for comments. —Reuters Staff Source
