# Disproportionality Analysis of Renal Adverse Events Associated with a Combination of Immune Checkpoint Inhibitors and Acid-Suppressing Agents—A Pharmacovigilance Study Based on the FAERS Database

## TL;DR

This study finds that combining immune checkpoint inhibitors with proton pump inhibitors increases the risk of kidney-related adverse events.

## Contribution

The study provides new evidence on the increased renal risk of combining immune checkpoint inhibitors with PPIs using real-world pharmacovigilance data.

## Key findings

- Combining PPIs with ICIs significantly elevates the risk of renal adverse events compared to monotherapy.
- Tubulointerstitial nephritis was the most frequently reported and intense renal adverse event in combination therapy.
- PD-1 monotherapy, omeprazole, and rabeprazole were associated with higher renal adverse event risks.

## Abstract

Background/Objectives: The nephrotoxicity of immune checkpoint inhibitors (ICIs) combined with proton pump inhibitors (PPIs) has been recognized but lacks a comprehensive analysis. We conducted an in-depth investigation of renal adverse events (rAEs) associated with ICIs and different acid-suppressing agents (ASAs)—including PPIs, histamine-2 receptor antagonists (H2RAs), and potassium-competitive acid blockers (P-CABs)—using real-world data from the FDA’s Adverse Event Reporting System (FAERS). Methods: We analyzed rAE reports from the FAERS database covering Q1 2004 to Q1 2023. Disproportionality analysis was conducted to identify rAEs associated with ICI or ASA monotherapy or combination therapy. Univariate logistic regression was employed to explore influencing factors. Results: No eligible rAE reports were retrieved for H2RAs and P-CABs. However, 6,775 reports in the ICI group, 54,055 reports in the PPI group, and 210 reports in the ICI–PPI combination therapy group were included in the final analysis. In PPI–ICI combination settings, tubulointerstitial nephritis had the highest reporting frequency and signal intensity; the overall risk of rAEs was significantly elevated compared to ICI or PPI monotherapy, with reporting odds ratios of 14. 65 (95% confidence interval [CI] 12.93–16.58) and 3.24 (95% CI 2.87–3.66), respectively; the median onset time was shortest at 21 days (interquartile range 5.5–135); and PD-1 monotherapy, omeprazole, and rabeprazole were associated with higher rAE risks. Conclusions: Our findings confirm that the combination of PPIs (but not other ASAs) with ICIs further increases the risk of various acute and chronic rAEs. Healthcare providers should exercise caution when managing patients on these therapies.