email article Adding a year of CDK4/6 inhibition to adjuvant endocrine therapy failed to improve invasive disease-free survival (iDFS) in early hormone receptor (HR)-positive breast cancer patients who had residual disease following neoadjuvant chemotherapy, a phase III trial showed. In the PENELOPE-B study of over 1,200 patients, no difference in the primary endpoint of iDFS was observed between the group receiving palbociclib (Ibrance) and those assigned to placebo, after a median follow-up of 43 months (stratified HR 0.93, 95% CI 0.74-1.17, P=0.525), reported Sibylle Loibl, MD, PhD, of the German Breast Group. "The addition of 1 year of palbociclib to endocrine therapy in patients with hormone receptor-positive/HER2-negative breast cancer and at high risk of relapse after neoadjuvant chemotherapy does not improve invasive disease-free survival," she said during her presentation at the virtual San Antonio Breast Cancer Symposium (SABCS). "No group could be identified with a higher benefit from palbociclib."