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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. IBRANCE® (palbociclib) Prescribing Information for Great Britain click here. IBRANCE® (palbociclib) Prescribing Information for Northern Ireland click here. Adverse event reporting information can be found at the bottom of the page.


Confidence In A Treatment You Can Manage1-6

Neutropenia (any grade) was the most frequently reported Adverse Event (AE) for IBRANCE® (palbociclib) in combination with Endocrine Therapy (ET):

  • 81.8% in PALOMA-2 extended follow up (IBRANCE® + letrozole arm)4
  • 84.1% in PALOMA-3 (IBRANCE® + fulvestrant arm)5

across the Phase III IBRANCE® Clinical Trial Programme.1

Incidence of Neutropenia

IBRANCE® Cumulative Incidence of Grade 3-4 Neutropenia*

Adapted from Verma S, et al. Oncologist. 2016;21:1165-752

* In a population of pre-/peri- and post-menopausal women with HR+/HER2- locally advanced breast cancer with relapse or progression on or after ET in the adjuvant setting, randomised to receive IBRANCE® + fulvestrant or placebo + fulvestrant. Data from all randomly assigned patients who received at least one dose of IBRANCE® plus fulvestrant.2​​​​​​​

IBRANCE® Neutropenia Rates

In clinical studies and clinical practice, most cases of Grade ≥3 Neutropenia occurred during the first two cycles of treatment.2,7

How IBRANCE® Neutropenia differs from Chemotherapy Neutropenia

Due to its mechanism of action, IBRANCE®-induced Neutropenia differs from that seen with Chemotherapy.2,8,9

Whilst IBRANCE® suppresses the bone marrow by inducing cell cycle arrest, Chemotherapy causes cellular death, including bone marrow cells.8,9

The 3:1 IBRANCE® Dosing Schedule provides a 1-week Recovery Period that allows arrested bone marrow cells to resume their function, while tumour cell growth remains suppressed by the concomitant ET partner.1,9

Cells affected by drug treatment

IBRANCE®-induced Neutropenia and Chemotherapy-induced Neutropenia are caused by Different Mechanisms8-11

Neutropenia Mechanism Table

AE : Adverse Event, ET : Endocrine Therapy, HR+/HER2– : Hormone Receptor Positive / Human Epidermal Growth Factor Receptor 2 Negative

This medicinal product is subject to additional monitoring. This will allow quick identification of new safety information. Healthcare professionals are asked to report any suspected adverse reactions. See section 4.8 of the SmPC for how to report adverse reactions.

  1. IBRANCE® Summary of Product Characteristics for Great Britain click here. IBRANCE® Summary of Product Characteristics for Northern Ireland click here.
  2. Verma S. et al. Oncologist. 2016;21:1165–75.
  3. Finn RS, et al. N Engl J Med. 2016;375:1925–36.
  4. Rugo HS, et al. Breast Cancer Res Treat. 2019;174:719–29.
  5. Turner NC, et al. N Engl J Med. 2018;379:1926–36.
  6. Cristofanilli M. et al. Lancet Oncol. 2016;17:425–39.
  7. Kish JK, et al. SABCS Annual Meeting, 2017, San Antonio, TX, USA. Poster P6-16-05
  8. Johnson SM, et al. J Clin Invest. 2010;120:2528-2536.
  9. Hu W, et al. Clin Cancer Res. 2015;22(8):2000-2008.
  10. Helleday T, et al. Nat Rev Cancer. 2008;8:193-204.
  11. Curtin NJ. Nat Rev Cancer. 2012;12:801-817. 
PP-IBR-GBR-3730. July 2021


  • IBRANCE® safety information and outcomes

  • IBRANCE® Safety Profile
  • Adverse Event Management

Clinical Trials

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


  • 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

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PP-PFE-GBR-2688. December 2020