ERBB2 and breast cancer: Herein, we describe prolonged clinical benefit with abemaciclib after clinical progression during palbociclib-based therapy in this setting.<h4>Case report</h4>A 59-year-old woman with stage IIIA HR+/HER2- breast cancer underwent modified radical mastectomy in 2016, followed by adjuvant AC-P (doxorubicin hydrochloride 70 mg, cyclophosphamide 800 mg, and paclitaxel liposomes 180 mg) chemotherapy, radiotherapy, and letrozole maintenance.