Palbociclib is a CDK4/6 inhibitor approved for advanced breast cancer. In the adjuvant setting, the potential value of adding palbociclib to endocrine therapy for hormone receptor-positive breast cancer has not been confirmed. The multinational phase 3 PALLAS trial, at 406 centers in 21 countries, randomized patients with HR-positive, HER2-negative breast cancer to endocrine therapy with or without palbociclib. There were no significant difference between the two groups for the primary endpoint invasive disease-free survival (84,2 versus 84,5% at 4 years) or for the secondary end points distant recurrence-free survival, locoregional cancer-free survival, and overall survival.
