Immune checkpoint inhibitors (ICIs) have transformed cancer treatment, but their effectiveness varies widely among patients. A growing body of clinical evidence, including meta-analyses and observational studies, indicates that the concurrent use of proton pump inhibitors (PPIs)βcommon drugs for acid refluxβis associated with significantly reduced efficacy of these immunotherapies.
Research suggests PPIs may alter the gut microbiome, which plays a crucial role in modulating the immune system's response to cancer. This dysbiosis is hypothesized to impair the anti-tumor immune activation that ICIs are designed to stimulate. Multiple studies have reported that cancer patients taking PPIs alongside ICIs show lower response rates, shorter progression-free survival, and reduced overall survival compared to those not on the acid-suppressing medication.
The clinical correlation is strong enough that several oncology guidelines and expert reviews now recommend physicians carefully evaluate the necessity of PPI therapy in patients scheduled for or undergoing immunotherapy. The findings underscore the importance of considering all medications, not just cancer drugs, in a patient's treatment regimen to optimize outcomes.
