Oops, you're using an old version of your browser so some of the features on this page may not be displaying properly.

MINIMAL Requirements: Google Chrome 24+Mozilla Firefox 20+Internet Explorer 11Opera 15–18Apple Safari 7SeaMonkey 2.15-2.23

Poster Display session 2

3536 - Palbociclib plus an aromatase inhibitor as first-line therapy for metastatic breast cancer in US clinical practices: Real-world progression-free survival analysis


29 Sep 2019


Poster Display session 2


Tumour Site

Breast Cancer


Mylin Torres


Annals of Oncology (2019) 30 (suppl_5): v104-v142. 10.1093/annonc/mdz242


M. Torres1, X. Liu2, J. Mardekian3, L. McRoy4

Author affiliations

  • 1 Department Of Radiation Oncology, Winship Cancer Institute, Emory University School of Medicine, 30322 - Atlanta/US
  • 2 Us Medical Affairs, Pfizer Inc, 07977 - Peapack/US
  • 3 Statistics, Pfizer Inc, 10017 - New York/US
  • 4 Global Medical Affairs, Pfizer Inc, 10017 - New York/US


Login to get immediate access to this content.

If you do not have an ESMO account, please create one for free.

Abstract 3536


CDK4/6 inhibitor in combination with an aromatase inhibitor (AI) as initial endocrine therapy has become standard of care for patients with HR+/HER2– advanced/metastatic breast cancer (mBC). Large representative studies are needed to understand effectiveness of CDK4/6 inhibitor + AI in the real-world clinical setting. This study describes patient characteristics and real-world progression-free survival (rwPFS) in mBC patients treated with Palbociclib + AI in the first line setting.


The Flatiron longitudinal database contains information from 2 million cancer patients treated in the US from 275 cancer clinics. From this database, 878 HR+/HER2– mBC women treated with Palbociclib + AI as first-line therapy between February 2015 and August 2018 with at least 3 months of follow-up available were identified. Patients were followed from start of Palbociclib + AI therapy to November 2018, death, or last visit, whichever came first. rwPFS was defined as months from start of Palbociclib + AI to death or disease progression based on clinical assessment or radiographic progression with or without biopsy confirmation. Kaplan-Meier methods were used to estimate survival proportions in rwPFS.


In our cohort of 878 eligible patients with a median follow-up of 19.4 months, 66.9% were white, mean age was 65.2 years, 50.8% had visceral disease (liver and/or lung involvement). Among these patients, 92.7% received Letrozole along with Palbociclib. Median rwPFS was 21.9 months (95%CI = 20.1 – 28.2). Table presents median rwPFS by subgroups.Table:

327P Real-world progression-free survival (rwPFS) by subgroups

NMedian rwPFS (months)95%CI
All patients87821.920.1 – 28.2
Age, year
 ≥ 7517728.620.1—NE
Menopausal status
 Premenopausal (Age≤50)6719.514.3—25.9
 Postmenopausal (Age>50)81122.420.2—28.7
Disease stage at initial diagnosis
 1 or 231121.917.6—33.1
 4 (De novo)35922.219.5—32.7
ECOG Score
No bone-only disease62317.314.6—20.2
Bone-only disease255NENE
Visceral disease44614.812.7—18.3
Nonvisceral disease43233.128.3—NE
No# of metastic sites

NE = not estimable


These findings from a large cohort of patients in US routine clinical practices support first-line Palbociclib + AI therapy as standard of care for HR+/HER2- advanced/metastatic breast cancer.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Pfizer Inc.


Pfizer Inc.


M. Torres: Full / Part-time employment: Emory University; Research grant / Funding (self): Pfizer Inc. X. Liu: Shareholder / Stockholder / Stock options, Full / Part-time employment: Pfizer Inc. J. Mardekian: Shareholder / Stockholder / Stock options, Full / Part-time employment: Pfizer Inc. L. McRoy: Shareholder / Stockholder / Stock options, Full / Part-time employment: Pfizer Inc.

This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used.

For more detailed information on the cookies we use, please check our Privacy Policy.

Customise settings
  • Necessary cookies enable core functionality. The website cannot function properly without these cookies, and you can only disable them by changing your browser preferences.