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Information relating to specific disease areas aligned to Pfizer’s portfolio and other resources designed for Pfizer medicines.

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The content of this website has been produced in line with the IBRANCE® Summary of Product Characteristics for Great Britain and Northern Ireland. IBRANCE® (palbociclib) Prescribing Information for Great Britain and Northern Ireland click here.  Adverse event reporting information can be found at the bottom of the page.

Mode of Action

Confidence in a Treatment that's Setting the Standard1-2

​​​​​​​The growth of HR+ breast cancer is dependent on cyclin D1, a direct transcriptional target of the ER3-4
a. Cyclin D1 activates CDK4/6 resulting in G1–S phase transition and entry into the cell cycle3-4
b. Cell-line models of endocrine resistance remain dependent on cyclin D1 and  CDK4/63-4

IBRANCE® is an orally active selective inhibitor of CDK4 and CDK6 kinases.5-6

IBRANCE® blocks Rb phosphorylation at concentrations of 9–15 nmol/l, inducing G1 arrest in Rb+ tumour cell lines.5

Synergy between ER and CDK4/6 has led to IBRANCE® being developed in combination with endocrine therapy as treatment for HR+/HER2- mBC.6​​​​​​​​

Adapted from Cadoo KA, et al. Breast Cancer Targets and Therapy. 2004;6:123–33.4

ER : Oestrogen Receptor, HR+ : Hormone Receptor Positive, HER2- : Human Epidermal growth factor Receptor 2-negative, mBC : metastatic Breast Cancer

  1. Rugo HS, et al. Breast Cancer Res Treat. 2019;174:719–29.
  2. Finn RS, et al. N Engl J Med. 2016;375:1925-1936.
  3. Thangavel C, et al. Endocr Relat Cancer. 2011;18:333–45.
  4. Cadoo KA, et al Breast Cancer Targets and Therapy. 2014;6:123–33.
  5. Fry DW, et al. Mol Cancer Ther. 2004;3:1427–38.
  6. VanArsdale T, et al. Clin Cancer Res. 2015;21:2905–10.
PP-IBR-GBR-4077. February 2022

Clinical Trials

  • Clinical Trial results for IBRANCE®
  • IBRANCE® Clinical Trials
  • PALOMA-2 Trial

    ​​​​​​​PALOMA-3 Trial


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IBRANCE® safety information and outcomes

  • IBRANCE® Safety Profile
  • Neutropenia
  • Adverse Event Management


  • IBRANCE® is indicated for the treatment of HR+/HER2- locally advanced or metastatic breast cancer:
       - In combination with an aromatase inhibitor; or
    ​​​​​​​   - In combination with fulvestrant in women who have received prior ET

    In pre- or perimenopausal women, the ET should be combined with a LHRH agonist

For UK Healthcare Professionals*

These pages are not intended for patients or for members of the general public. The healthcare professional web pages contain promotional content.

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*The ABPI Code definition for healthcare professional is members of the medical, dental, pharmacy and nursing professionals and any other persons who in the course of their professional activities may administer, prescribe, purchase, recommend or supply a medicine.

PP-PFE-GBR-3863. November 2021



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