Abstract

Concomitant intake of proton pump inhibitors (PPIs) may create drug-drug interactions, potentially impacting efficacy of anticancer agents. In the phase III PALLAS trial, the addition of palbociclib capsules to standard adjuvant endocrine therapy in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative early breast cancer did not improve invasive disease-free survival (iDFS). We explored whether concomitant use of PPIs affected survival outcomes in patients treated with palbociclib in PALLAS.