Antibiotic Susceptibility-Guided Concomitant Therapy Regimen with Vonoprazan, High-Dose Amoxicillin, Clarithromycin, and Metronidazole for Helicobacter pylori Eradication as Fourth-Line Regimen: An Interventional Study.

This is the first registered intervention study for vonoprazan, high-dose amoxicillin, clarithromycin, and metronidazole 14-day concomitant therapy based on a susceptibility test of Helicobacter pylori. We conducted this study as a fourth-line rescue regimen in Japan.

Methods: Twenty patients who underwent three rounds of eradication therapies (first- or second-line 7-day triple therapy consisting of amoxicillin and clarithromycin, or metronidazole- and sitafloxacin-based third-line therapy) and had failed eradication based on a urea breath test or fecal antigen test were recruited. All patients underwent endoscopic examination and culture tests before starting eradication therapy. The intervention was concomitant therapy consisting of vonoprazan 20 mg bid, amoxicillin 500 mg qid, clarithromycin 400 mg bid, and metronidazole 250 mg bid for 14 days, which were modified based on the susceptibility test, and the resistant drugs were removed from the regimen. Patients with negative culture results were treated with quadruple therapy. The primary outcome was the eradication rate (UMIN000025765, jRCTs 031180208).

Results: The eradication rate of susceptibility-testing-based fourth-line eradication therapy was 63.2% (95%CI: 38.4-83.7%) in intent-to-treat analysis and 70.6% (95%CI: 44.0-89.7%) in per-protocol analysis. Thirteen patients received quadruple therapy, with eradication rates of 61.5% and 75.0%, respectively. No serious adverse events were reported.

Conclusions: This vonoprazan-based concomitant therapy modified by the susceptibility test is a potential option as fourth-line eradication after first-line clarithromycin-based 7-day triple, second-line metronidazole-based 7-day triple, and third-line sitafloxacin-based 7-day triple therapy failure.