NanoString Announces Study Confirms Ability of Prosigna Assay to Assess Risk of Late Distant Recurrence in Postmenopausal Women With Estrogen Receptor-Positive Breast Cancer

NanoString Technologies, Inc.,

a provider of life science tools for translational research and molecular diagnostic products, today announced that a study published online in Clinical Cancer Research showed that the PAM50 assay, on which the company's Prosigna™ Breast Cancer Prognostic Gene Signature Assay is based, accurately assessed the risk of late distant recurrence in postmenopausal women with estrogen receptor-positive (ER+) early-stage breast cancer. The study, titled, “The PAM50 Risk-of-Recurrence Score Predicts Risk for Late Distant Recurrence after Endocrine Therapy in Postmenopausal Women with Endocrine-Responsive Early Breast Cancer” was conducted by researchers from the Austrian Breast & Colorectal Cancer Study Group and can be found online at: http://clincancerres.aacrjournals.org/content/early/2014/02/11/1078-0432.CCR-13-1845.abstract. “There is an urgent unmet clinical need to accurately differentiate breast cancer patients who remain at high risk of distant recurrence beyond five years after diagnosis,” said senior author Michael Gnant, M.D., Professor at the Medical University of Vienna in Austria. “Prosigna's ability to predict late recurrences may enable identification of patients with endocrine-responsive breast cancer who can be spared extended adjuvant therapy in the future.” Study authors found that the Prosigna Breast Cancer Assay significantly increased prognostic accuracy with respect to late distant recurrence compared to a score based on clinical factors alone. Between years five and 15 after diagnosis in patients who had not had a recurrence at five years, patients categorized as low risk by the Prosigna Assay demonstrated a risk of distant recurrence of 2.4 percent compared to a risk of 17.5 percent in the high-risk group. The ability to accurately assess risk of late distant recurrence was observed for patients with both node-positive and node-negative disease. “The ability to stratify patients according to risk of late distant recurrence significantly differentiates the Prosigna Assay from other genomic-based breast cancer assays,” said Brad Gray, President and Chief Executive Officer of NanoString Technologies. “We believe that this feature provides the potential to expand the clinical utility of the Prosigna Assay, helping to inform treatment decisions that physicians struggle with today.” Results described in the Clinical Cancer Research paper build on data presented at the 2013 San Antonio Breast Cancer Symposium as well as a paper recently published in the Journal of the National Cancer Institute (JNCI). Authors of the JNCI 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 (see www.nanostring.com/company/corp_press_release?id=94).