A new analysis of the landmark PACIFIC trial reveals that common medications — proton pump inhibitors (PPIs) like omeprazole and antibiotics — may reduce how well immunotherapy works in lung cancer patients. Among those receiving durvalumab after chemoradiotherapy for stage III non-small cell lung cancer, PPI users had a median overall survival of 33 months versus nearly 58 months in non-users. Antibiotic exposure was tied to shorter progression-free survival. Researchers believe the mechanism likely involves disruption of the gut microbiome, which plays a critical role in immune function. The findings call for more careful management of routine medications when patients are undergoing immunotherapy, with broader implications for anyone using immune checkpoint inhibitors.
