-2%
Palbocent is a selective cyclin-dependent kinase (CDK) 4 and 6 inhibitor, used in the management of:
- Hormone receptor (HR)-positive, HER2-negative advanced or metastatic breast cancer
- In combination with aromatase inhibitors as first-line endocrine therapy in postmenopausal women
In combination with fulvestrant in women with progression after prior endocrine therapy
Palbociclib targets CDK4 and CDK6, enzymes vital to cell cycle progression. These kinases, when bound to cyclin D1, phosphorylate the retinoblastoma (Rb) protein, releasing E2F transcription factors and allowing cells to transition from the G1 phase to the S phase.
By inhibiting CDK4/6, Palbociclib prevents this progression, resulting in cell cycle arrest, particularly in ER-positive breast cancer cells. When used with antiestrogens (like fulvestrant or aromatase inhibitors), this inhibition is enhanced, promoting cellular senescence and reducing tumor proliferation.
Preclinical studies have shown that the combination therapy results in:
- Stronger inhibition of Rb phosphorylation
- Reduced E2F signaling
- Enhanced tumor suppression
- Sustained growth arrest even after drug withdrawal