Palbociclib combined with endocrine treatment in breast cancer patients with high relapse risk after neoadjuvant chemotherapy: Subgroup analyses of premenopausal patients in PENELOPE-B.

518Background: PENELOPE-B assessed efficacy of the CDK4/6 inhibitor 1-year palbociclib versus placebo added to endocrine therapy (ET) as post-neoadjuvant treatment in a high-risk breast cancer popu...