From the Guidelines
Palbociclib should be given in combination with an aromatase inhibitor, such as letrozole, or fulvestrant for the treatment of hormone receptor-positive, HER2-negative advanced or metastatic breast cancer. The standard dosing regimen is 125 mg once daily for 21 consecutive days followed by 7 days off treatment (28-day cycle) 1. When using palbociclib with an aromatase inhibitor, the aromatase inhibitor is administered continuously throughout the 28-day cycle. When combining with fulvestrant, fulvestrant is given as 500 mg intramuscularly on days 1,15, and 29, and then monthly thereafter 1.
Some key points to consider when administering palbociclib include:
- Patients should take palbociclib with food to improve absorption and reduce variability in exposure
- Monitoring for neutropenia is crucial, with complete blood counts recommended before starting treatment, at the beginning of each cycle, and on day 15 of the first two cycles 1
- Dose modifications may be necessary based on tolerability
- This combination therapy works by targeting different aspects of cancer cell growth - palbociclib inhibits cyclin-dependent kinases 4 and 6 (CDK4/6) to prevent cell cycle progression, while the hormonal therapy prevents estrogen-driven tumor growth 1.
It's also important to note that although no data exist at present, any aromatase inhibitor could be substituted depending on individual tolerance 1. On the basis of the data from PALOMA-3, palbociclib can also be combined with fulvestrant in the second-line setting or greater, including after one line of chemotherapy 1.
From the FDA Drug Label
IBRANCE is a kinase inhibitor indicated for the treatment of adult patients with 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 (1); or • fulvestrant in patients with disease progression following endocrine therapy. IBRANCE capsules are taken orally with food in combination with an aromatase inhibitor or fulvestrant.
Palbociclib can be given with:
- Aromatase inhibitors as initial endocrine-based therapy
- Fulvestrant in patients with disease progression following endocrine therapy It is recommended to take IBRANCE capsules orally with food. 2
From the Research
Palbociclib Combination Therapies
Palbociclib can be given in combination with the following therapies:
- Fulvestrant: as indicated by studies 3, 4, 5
- Letrozole: as a first-line treatment for ER-positive, HER2-negative, advanced breast cancer, as shown in studies 4, 6, 7
- Aromatase inhibitor: as initial endocrine-based therapy, as mentioned in study 4
- Luteinizing hormone-releasing hormone agonist: in combination with fulvestrant, as indicated in study 4
Key Findings
- The combination of palbociclib with fulvestrant or letrozole has been shown to significantly prolong progression-free survival (PFS) and improve clinical benefit response (CBR) rates in patients with HR-positive, HER2-negative advanced or metastatic breast cancer 3, 4, 6, 7
- Neutropenia is the most common adverse event associated with palbociclib combination therapies, but it can be effectively managed with dose modifications without compromising efficacy 3, 4, 6, 5, 7