Impact of early dose intensity reduction of Palbociclib on clinical outcomes in patients with hormone-receptor-positive metastatic breast cancer

• Published in: Breast cancer research and treatment 2020-09, Vol.183 (2), p.411-418
• Main Authors: Moftakhar, Bahar, Lekkala, Manidhar, Strawderman, Myla, Smith, Tae C., Meacham, Philip, Fitzgerald, Bryan, Falkson, Carla I., Dhakal, Ajay
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Aromatase; Aromatase Inhibitors - therapeutic use; Breast cancer; Breast Neoplasms - drug therapy; Breast Neoplasms - metabolism; Breast Neoplasms - mortality; Breast Neoplasms - pathology; Cancer research; Care and treatment; Clinical outcomes; Clinical Trial; Cyclin-Dependent Kinase 4 - antagonists & inhibitors; Cyclin-Dependent Kinase 6 - antagonists & inhibitors; Drug Tapering - methods; ErbB-2 protein; Estrogen Receptor alpha - metabolism; Female; Fulvestrant; Hormones; Humans; Medicine; Medicine & Public Health; Metastases; Metastasis; Middle Aged; Neoplasm Metastasis; Oncology; Patient outcomes; Piperazines - therapeutic use; Protein Kinase Inhibitors - therapeutic use; Pyridines - therapeutic use; Receptor, ErbB-2 - metabolism; Retrospective Studies; Survival Rate; Treatment Outcome
• ISSN: 0167-6806; 1573-7217
• DOI: 10.1007/s10549-020-05793-1

Background Palbociclib is commonly added to an aromatase inhibitor (AI) as first-line therapy in ER + HER2- metastatic breast cancer (MBC). There are no data on the effect of the relative dose intensity (RDI) of palbociclib in first-line setting on clinical outcomes. The objective of this study is to explore the association of RDI and dose reduction of palbociclib in the first-line setting with PFS. Methods This is a retrospective study of ER + HER2- MBC patients who received palbociclib plus AI in first-line setting. Subjects ≥ 18 years old with MBC, who were started on palbociclib 125 mg daily, had completed ≥ 1 cycle of palbociclib, and did not progress within the first 12 weeks were eligible. Analyses were performed at 12- and 36-week landmarks (LM). RDI was defined as the total amount of palbociclib taken per the total amount planned. RDI-high-12 and RDI-low-12 cohorts were defined as patients receiving palbociclib with RDI ≥ 80% and RDI