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Study Published Showing Advantages of the PAM50 Gene Signature, the Basis for Prosigna, in Helping to Estimate Risk of Late Distant Recurrence in Postmenopausal Estrogen Receptor Positive Breast Cancer Patients

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NanoString Technologies, Inc., (NASDAQ: NSTG) a provider of life science tools for translational research and molecular diagnostic products, recently announced that a study published online in the Journal of the National Cancer Institute demonstrated that the PAM50 gene signature, which is the basis for the Prosigna™ Breast Cancer Prognostic Gene Signature Assay, provides important information to help estimate the risk of late distant recurrence in postmenopausal women with estrogen receptor positive (ER+) early-stage breast cancer. After comparing the PAM50 gene signature, the Oncotype DX® Breast Cancer Assay and the IHC4 score, the authors concluded that the PAM50 gene signature provided the strongest prognostic information regarding risk of distant recurrence five to 10 years following diagnosis in postmenopausal ER+ early-stage breast cancer patients treated with five years of endocrine therapy.

Despite recent improvements in breast cancer treatment, some women with ER+ early-stage breast cancer remain at risk of disease recurrence after remaining disease-free for the first five years following diagnosis. Identifying newly diagnosed women with ER+ breast cancer who are at highest risk of having their cancer recur between five and 10 years after diagnosis is a priority for oncologists seeking a tool to help breast cancer patients make more informed treatment decisions.

The goal of this study was to compare the ability of three breast cancer assays to predict risk of distant recurrence separately in years 0 to 5 and years 5 to 10 after diagnosis for postmenopausal women with ER+ early-stage breast cancer. The three breast cancer assays included in the study were the PAM50 gene signature, the Oncotype DX Breast Cancer Assay, and the IHC4 score, derived from immunohistochemical assessment of ER, PR, HER2 and Ki67 genes. The study included 940 samples from the landmark ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial of postmenopausal women with ER+ early-stage breast cancer treated with five years of endocrine therapy. The study was performed on RNA extracted from tumor samples by Genomic Health, Inc. for validation of the Oncotype DX Breast Cancer Assay.

The researchers concluded that the PAM50 gene signature was the only breast cancer assay of the three evaluated that showed promise in predicting late recurrence and in categorizing patients into low and high risk for late distant recurrence. Although PAM50, Oncotype DX, and IHC4 each added overall prognostic information in the late follow-up period, PAM50 was the best discriminator of patients into low-risk and high-risk groups for late distant recurrence. Of the three assays evaluated, PAM50 provided the strongest risk score in the five to 10 year period for all patient subgroups evaluated in this study.

This publication expands upon a presentation at IMPAKT 2013 on a study in 1,478 patients from the ABCSG8 clinical trial, which demonstrated that the Prosigna Assay added prognostic information about the risk of late recurrence of breast cancer to the standard pathological variables in postmenopausal women with hormone receptor positive (HR+), node-positive and node-negative early-stage breast cancer (p<0.0001). Patients categorized as low risk based on the Prosigna Assay had Distant Recurrence Free Survival (DRFS) between years five and 10 of 98.7%, while patients categorized as high risk had DRFS between years five and 10 of 91.5%.

“We are pleased that this study further differentiates the performance of the Prosigna Breast Cancer Assay from first-generation genomic breast cancer assays,” said Brad Gray, President and Chief Executive Officer of NanoString Technologies. “This second peer-reviewed article follows quickly on the heels of the publication of our TransATAC clinical validation study and FDA 510(k) clearance, and contributes to a growing body of evidence of Prosigna’s ability to provide prognostic information that supports future inclusion of Prosigna in treatment and reimbursement guidelines.”

The study, entitled “Factors predicting late recurrence for estrogen receptor positive breast cancer,” was conducted by researchers in London at the Centre for Cancer Prevention, Wolfson Institute of Preventive Medicine, Queen Mary University and the Academic Department of Biochemistry, Royal Marsden Hospital, in cooperation with scientists at NanoString Technologies. It was published online in JNCI.

Study: Factors Predicting late recurrence for estrogen receptor–Positive Breast cancer [Journal of the National Cancer Institute]

Source: NanoString Technologies