Timing and intensity of proton pump inhibitor exposure hampers overall survival in patients with metastatic non-small cell lung cancer treated with immune checkpoint inhibitors

Introduction: Proton pump inhibitor (PPI) use has been associated with reduced immune checkpoint inhibitor (ICI) efficacy in metastatic non-small cell lung cancer (mNSCLC) with evidence limited to their use during a short time period around ICI initiation. This study evaluated the associations between the timing and intensity of PPI exposure up to one year before ICI initiation and overall survival (OS) in mNSCLC patients treated with ICIs. Methods: This retrospective cohort study included consecutive mNSCLC patients treated with ICIs within routine clinical practice. Patients were grouped by the timing of PPI exposure from 365 days before to 30 days after (−365 to +30 days) ICI initiation: (1) no PPIs within −365 to +30 days