Study shows effectiveness of PAM50-based Prosigna Breast Cancer Prognostic Gene Signature Assay

NanoString Technologies, Inc. (NASDAQ:NSTG), a provider of life science tools for translational research and molecular diagnostic products, today announced new results from a combined analysis of the Austrian Breast & Colorectal Cancer Study Group 8 (ABCSG-8) and Trans-Arimidex, Tamoxifen, Alone or in Combination (TransATAC) studies. These results, which evaluated samples from 2,137 patients, suggest that the PAM50-based Prosigna^™ Breast Cancer Prognostic Gene Signature Assay may help identify women with late distant recurrence after five years of endocrine treatment. Using the Prosigna Assay, the study investigators classified patient tumors by subtype and found that patients with Luminal B subtype have three times higher risk of late distant recurrence than patients with Luminal A subtype tumors. Results were presented today at the 2013 San Antonio Breast Cancer Symposium.

"Women with estrogen receptor positive breast cancer have a high risk of recurrence for at least 10 years after diagnosis, even after five years of endocrine therapy. To provide better care for these women, more informative biomarkers are needed to help predict risk of late recurrence," said Ivana Sestak, PhD, The Centre for Cancer Prevention, Wolfson Institute of Prevention Medicine, Queen Mary University and lead investigator of this study. "As a result of our study, we determined that the risk of recurrence score, or ROR score generated by the PAM50-powered Prosigna Assay provides significant prognostic information that may be used by oncologists and pathologists to help guide care decisions for postmenopausal women with hormone receptor-positive breast cancer who may be at higher risk of late distant recurrence of disease in the absence of additional treatment."

Authors of the study reported that the ROR score, also known as the Prosigna Score, added prognostic information about the risk of 10-year distant recurrence beyond that provided by standard clinical-pathological variables in the analysis of all patients studied. In addition, the study reported that patients with Luminal A subtype (4.1 percent) had a lower risk of recurrence than those with the Luminal B subtype (12.9 percent) further supporting the biological differences between these groups.

"Few studies have addressed the prognostic value of molecular scores for late recurrence. These results add to the growing body of data supporting the clinical potential of the PAM50 gene signature and the Prosigna Breast Cancer Assay as a valuable prognostic tool for patients and their doctors," said Brad Gray, President and Chief Executive Officer of NanoString Technologies.

Results presented today at the 2013 San Antonio Breast Cancer Symposium build on a recently published paper in the Journal of the National Cancer Institute titled, "Factors predicting late recurrence for estrogen receptor positive breast cancer." Authors of this paper found that the PAM50 gene signature was better than Oncotype DX^® and IHC4 Assays at categorizing patients into low and high risk for late distant recurrence of disease.