BIG Breast International Group
We will find a cure for breast cancer through global research and collaboration.


Post-neoadjuvant palbociclib for patients with hormone-receptor-positive, HER2-normal primary breast cancer with high relapse risk

 Last update: December 2016


The PENELOPE-B study is designed to demonstrate that, when used with standard endocrine therapy, palbociclib provides superior invasive disease-free survival (iDFS) compared to placebo in pre- and postmenopausal women with hormone receptor (HR)-positive/HER2-normal early breast cancer at high risk of relapse after showing less than pathological complete response to neoadjuvant taxane- containing chemotherapy. Treatment with palbociclib may be an attractive option with a favourable safety profile for these patients.


About one third of patients with HR-positive, HER2-normal breast cancer and residual disease after neoadjuvant chemotherapy have a substantial risk of relapse. The clinical-pathologic stage--estrogen/grade (CPS-EG)1 – which combines clinical stage before neoadjuvant treatment, pathological stage after neoadjuvant treatment, grading and estrogen-receptor status – can be used to identify these patients.

The CPS-EG score was validated in 2454 patients with HR-positive/HER2-normal tumours using data obtained from the German neoadjuvant studies' meta-database. Patients who had a score of 3 or higher or a score of 2 and residual node-positive (ypN+) disease show a 3-year iDFS of 77%, despite adequate local therapy and adjuvant endocrine treatment. Cyclin dependent kinases (CDK), a group of serine/threonine kinases, play a key role in regulating cell cycle progression by interacting with specific cyclin proteins in luminal-type tumours. Palbociclib is an oral, highly selective inhibitor of CDK4/6 kinase activity that prevents cellular DNA synthesis by prohibiting progression of the cell cycle from the G1 to S phase by blocking retinoblastoma (Rb) phosphorylation. Four Preclinical studies identified luminal ER subtype, elevated expression of cyclin D1 and Rb protein, and reduced p16 expression as being associated with sensitivity to palbociclib.

The main objective of PENELOPE-B is to demonstrate that palbociclib provides superior invasive disease-free survival (iDFS) in this high-risk population of patients.



WHO Patients

The objective is to recruit 800 patients.


This study is sponsored and conducted by the German Breast Group (GBG) under the Breast International Group (BIG) umbrella. Participating groups include the Arbeitsgmeinschaft Gynäkologische Onkologie (AGO) Study Group and The National Surgical Adjuvant Breast and Bowel Project (NSABP) Foundation Inc., Pfizer is the pharmaceutical partner. 


The study was launched in late 2013 and is expected to recruit patients through late 2017. The final overall survival results are anticipated in 2021.


200-250 sites in Australia, Austria, Brazil, France, Germany, Ireland, Italy, Japan, Korea, Spain, UK, US/Canada




Pfizer Identifier: NCT01864746

Further information:

Scroll to top

Contact us

Breast International Group (BIG)-aisbl Blvd de Waterloo 121 B-1000 Brussels | Belgium VAT BE 0468 176 240