Class/mechanism: Cyclin-dependent kinase 4 and 6 inhibitor. Cyclin D1, CDK4, and CDK6 are downstream of signaling pathways which result in cellular proliferation. The use of palbociclib with antiestrogens was observed to increase growth arrest in estrogen receptor (ER)-positive breast cancer cell lines by decreasing retinoblastoma protein (Rb) phosphorylation, which resulted in reduced E2F expression and signaling. Palbociclib has been observed to cause cell cycle arrest between G1 to S phase of the cell cycle in ER-positive breast cancer cell lines.
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Diseases for which it is used
Patient drug information
History of changes in FDA indication
- 2/3/2015: Accelerated FDA approval to be used "in combination with letrozole for the treatment of postmenopausal women with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer as initial endocrine-based therapy for their metastatic disease."
- 2/19/2016: FDA approval expanded "in combination with fulvestrant for the treatment of women with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer with disease progression following endocrine therapy."
- 3/31/2017: FDA granted regular approval "for the treatment of hormone receptor (HR) positive, human epidermal growth factor receptor 2 (HER2) negative advanced or metastatic breast cancer in combination with an aromatase inhibitor as initial endocrine based therapy in postmenopausal women."
Also known as
- Code name: PD-0332991
- Brand name: Ibrance