{
  "abstract": "Background and Importance Immune checkpoint inhibitors (ICI) have become a standard treatment in multiple malignancies. However, their efficacy may be influenced by concomitant medications that alter the gut microbiome. Among them, proton pump inhibitors (PPI), widely prescribed, have been associated in retrospective studies with reduced immunotherapy efficacy. Nevertheless, results from real-world cohorts remain heterogeneous.Aim and Objectives To evaluate whether PPI use within 30 days prior to pembrolizumab initiation or during treatment impacts progression-free survival (PFS) and overall survival (OS) in patients with metastatic non-small-cell lung adenocarcinoma (NSCLC) with PD-L1 expression ≥50%.Material and Methods A retrospective, observational study was conducted at a tertiary hospital. Patients with metastatic NSCLC and PD-L1 ≥50% treated with pembrolizumab monotherapy in first-line between January 2019 and September 2025 were included.Collected variables were demographics, smoking status, ECOG, treatment dates, PPI use (obtained from pharmacy dispensing records), date of progression, and death. PFS was defined as the time from pembrolizumab initiation to disease progression, and OS as the time to death. Medians were estimated using Kaplan–Meier survival curves. Patients were stratified according to PPI exposure, either within 30 days prior to or during treatment. For categorical variables such as sex and smoking, Fisher’s exact test was applied.Results A total of 44 patients were included.– PPI use within 30 days prior to pembrolizumab: median PFS was 7.0 months in users vs 10.0 months in non–users; median OS was 11.0 vs 25.0 months.– PPI use during pembrolizumab: median PFS was 9.1 vs 10.8 months; median OS was 10.6 months in users, while not reached in non–users.No significant differences were found between groups regarding sex (p=0.49) or smoking status (p=0.14), indicating adequate baseline balance.Conclusion and Relevance In real-world clinical practice, concomitant PPI exposure may negatively impact both PFS and OS in patients treated with pembrolizumab. These findings, consistent with previous literature, highlight the importance of critically evaluating PPI prescriptions in oncology patients. Avoiding unnecessary PPI use may contribute to improved immunotherapy outcomes.Further multicentre prospective studies are needed to confirm these observations.Conflict of Interest No conflict of interest",
  "authors": [
    {
      "affiliations": [
        "Hospital Universitario Torrecárdenas, Servicio De Farmacia, Almería, Spain"
      ],
      "name": "MG Díaz López"
    },
    {
      "affiliations": [
        "Hospital Universitario Torrecárdenas, Servicio De Farmacia, Almería, Spain"
      ],
      "name": "P Nieto Guindo"
    },
    {
      "affiliations": [
        "Hospital Universitario Torrecárdenas, Servicio De Farmacia, Almería, Spain"
      ],
      "name": "E Romero Carreño"
    },
    {
      "affiliations": [
        "Hospital Universitario Torrecárdenas, Servicio De Farmacia, Almería, Spain"
      ],
      "name": "E Martinez Velasco"
    },
    {
      "affiliations": [
        "Hospital Universitario Torrecárdenas, Servicio De Farmacia, Almería, Spain"
      ],
      "name": "S Cifuentes Cabello"
    },
    {
      "affiliations": [
        "Hospital Universitario Torrecárdenas, Servicio De Farmacia, Almería, Spain"
      ],
      "name": "E Molina Cuadrado"
    }
  ],
  "title": "5PSQ-089 Impact of proton pump inhibitor exposure on progression-free and overall survival in patients treated with immune checkpoint inhibitors",
  "uid": "a6f2c0a0-a24d-53ce-bb43-6bc6d08ba926"
}