Susceptibility-guided therapy for Helicobacter pylori-infected penicillin-allergic patients: A prospective clinical trial of first-line and rescue therapies

Background Helicobacter pylori (H pylori) treatment remains a challenge for penicillin-allergic patients. Aim To evaluate the efficacy and tolerability of susceptibility-guided first-line and rescue treatment in H pylori-infected penicillin-allergic patients. Methods Consecutive H pylori-infected patients with penicillin allergy received a 14-day triple or quadruple therapy based on susceptibility to clarithromycin, levofloxacin, and metronidazole. All received esomeprazole 20 mg twice a day. Metronidazole-susceptible infections received metronidazole plus clarithromycin or levofloxacin triple therapy if susceptible. Clarithromycin- and levofloxacin-resistant infections received metronidazole plus tetracycline triple therapy. Metronidazole-resistant infections received a bismuth-high-dose metronidazole plus clarithromycin or levofloxacin quadruple therapy. Triple-resistant infections received classical bismuth quadruple therapy with high-dose metronidazole. Antimicrobial susceptibility was assessed using the E test method. Results 112 patients were entered (34.8% men, average 47.1 years). Infections in 83.8% (31/37) of treatment-naive subjects and 12.0% (9/75) (P < .001) receiving rescue treatment were susceptible to at least one of the three tested antibiotics. Overall, susceptibility-guided therapy achieved eradication rates of 92.9% (104/112, 95% CI 88.1%-97.7%) by intent-to-treat analysis and 99% (100/101, 95% CI 97.1%-100%) by per-protocol analysis. All regimens achieved eradication rates greater than 90% (P = .327) in the PP populations. Adverse events were relatively frequent; however, compliance remained high. Conclusion Susceptibility-guided therapy proved highly effective for penicillin-allergic patients. When available and proven locally effective, the alternative was empiric classical bismuth quadruple therapy. This trial is registered with ClinicalTrials.gov as NCT03708848.