First-line eradication regimens in penicillin-allergic patients in Andalusia. Results from the European Registry HP-EuReg in the 2013–2025 period.

<title>Abstract</title> Introduction and aims: Eradication treatment of Helicobacter pylori (HP) infection remains a challenge in patients allergic to penicillin, particularly in areas with high clarithromycin resistance rates such as Andalusia (close to 20%). Therefore, our objective was to analyze the evolution of first-line regimens in penicillin-allergic naïve patients, assessing effectiveness, safety, and adherence. Materials and methods: A descriptive observational study based on the Hp-EuReg registry was conducted. Penicillin-allergic patients receiving first-line treatment between 2013 and 2025 in eleven centers in Andalusia were included. Demographic, clinical, and treatment-related variables were analyzed. Effectiveness was assessed using a modified intention-to-treat analysis. Results: Of 5,942 registered patients, 247 (4.2%) were naïve and allergic to penicillin. The most frequently used regimen was single-capsule bismuth quadruple therapy (Pylera®) (61.8%), followed by triple therapies (29.7%). Pylera achieved an eradication rate of 93.9%, significantly higher than that of triple therapies (p&lt;0.001). The standard dose of proton pump inhibitors (PPI) was the most commonly prescribed, and the most frequent treatment duration was 10 days; however, neither variable reached statistical significance in terms of effectiveness. Overall adherence was optimal (97.1%), and the incidence of adverse events was low (≈9%), predominantly mild. Conclusion: Pylera® has become established as the most effective and safe first-line strategy in penicillin-allergic naïve patients, reflecting appropriate adaptation of clinical practice in Andalusia to the available scientific evidence. Abbreviations: Helicobacter pylori (HP), proton pump inhibitor (PPI), mucosa-associated lymphoid tissue lymphoma (MALT), intention-to-treat analysis (ITT), modified intention-to-treat analysis (mITT).