Baek YH, Kang EJ, Hong S, et al. - Proton pump inhibitor (PPI) use was shown to be linked with poor prognosis in non-small cell lung cancer (NSCLC) patients treated with immune checkpoint inhibitors (ICIs).

• In this study, the link between concomitant use of PPIs and ICIs and poor prognosis in NSCLC was examined.

• Using a nationwide healthcare database in South Korea, this cohort study included 2,963 patients treated with ICIs as second-line or later therapy for stage ≥ IIIB NSCLC.

• Following 1:1 propensity score-matching, there remained 1,646 patients, in whom concomitant PPI use was found to be linked with a 28% elevated risk of all-cause death, vs non-use (adjusted hazard ratio (HR) 1.28).

• On restricting the analysis to new users of PPI, an increased risk was noted (adjusted HR, 1.64).

• In subgroup analysis, PPI use was identified to be related to high mortality risk in patients with viral hepatitis (adjusted HR, 2.72).