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: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care

4136 - The Prevalence of PIK3CA Mutations in HR+/HER2– Metastatic Breast Cancer (BELLE2, BELLE3 and BOLERO2 clinical trials)

Date

22 Oct 2018

Session

Poster display session: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care

Topics

Targeted Therapy

Tumour Site

Breast Cancer

Presenters

Kitty Wan

Citation

Annals of Oncology (2018) 29 (suppl_8): viii90-viii121. 10.1093/annonc/mdy272

Authors

K. Wan1, Y.A. Wang2, M. Kaper3, M. Fritzemeier4, N. Babbar5

Author affiliations

  • 1 Biostatistics, Novartis Pharma AG, 4056 - Basel/CH
  • 2 Biostatistics, Novartis Institutes for BioMedical Research, 02139 - Cambridge/US
  • 3 Biostatistics, Novartis Pharmaceuticals Corporation, 07936-1080 - East Hanover/US
  • 4 Oncology Precision Medicine, Novartis Institutes for BioMedical Research, 02139 - Cambridge/US
  • 5 Oncology Precision Medicine, Novartis, 07936 - East Hanover/US
More

Resources

Abstract 4136

Background

Breast cancer (BC) is the most common form of malignant tumor in women worldwide. 60-70% of BC are hormone receptor-positive (HR+), HER2-negative (HER2–). The purpose of this analysis was to enhance understanding on the epidemiology for women with PIK3CA-mutant HR+/HER2– metastatic breast cancer (mBC).

Methods

PIK3CA mutations were tested from tumor biopsy (N = 1617) and circulating tumor DNA (ctDNA) (N = 1466) from patients enrolled into BOLERO-2, BELLE-2 and BELLE-3, which are three randomized Phase III studies in HR+/HER2– mBC. Various PIK3CA mutation testing methods were applied, including Next-Generation Sequencing (NGS) and Polymerase Chain Reaction (PCR) for tumor biopsies, as well as BEAMing and droplet digital PCR for ctDNA samples.

Results

Prevalence of the PIK3CA mutations among tissue biopsies ranged from 34.1% to 41.1% while prevalence of the PIK3CA mutations among liquid biopsies ranged from 27.5% to 43.3%. Besides gene-level analysis, the PIK3CA prevalence by hot spots and by exons was examined as well. Further, subgroup analysis of PIK3CA prevalence had been conducted based on patient cohort (2L vs 3L), mutation testing methods, ethnicity, biopsy source (primary tissue vs metastatic) and previous treatment.

Conclusions

PIK3CA mutations (specifically hotspots H1047R, E545K and E542K) frequently occur in HR+/HER2– mBC. The prevalence of PIK3CA mutations are in a relatively narrow range across the three randomized Phase III studies in HR+/HER2– mBC regardless of tissue types and testing methods.

Clinical trial identification

Legal entity responsible for the study

Novartis Pharma.

Funding

Novartis Pharma.

Editorial Acknowledgement

Disclosure

K. Wan: Employment: Novartis Pharma AG; Stock options: Novartis. Y.A. Wang, N. Babbar, M. Kaper, M. Fritzemeier: Employment: Novartis Pharmaceutical Corporation; Stock options: Novartis.

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.