Retrospective cohort study of association of concomitant use of proton pump inhibitors with efficacy of palbociclib for breast cancer

Proton pump inhibitors (PPIs) are commonly used drugs to relieve gastrointestinal symptoms, but they can negatively affect the bioavailability of orally administered concomitant drugs. A retrospective cohort study of 1310 South Korean women using palbociclib for advanced breast cancer found that progression-free and overall survival were shorter in the concomitant PPI group than in the non concomitant PPI group. The authors conclude that taking PPIs concomitantly with palbociclib may interrupt the full therapeutic benefits of palbociclib for breast cancer.