NanoString Technologies this week announced the publication of a study in Clinical Cancer Research showing that the PAM50 assay, on which its Prosigna breast cancer prognostic operates, accurately determined the risk of late distant recurrence – or recurrence between 5 and 15 years after diagnosis -- in postmenopausal women with estrogen receptor-positive, early-stage breast cancer, regardless of nodal status.
The authors reported that the Prosigna Breast Cancer Assay compared to clinical factors alone, "significantly increased prognostic accuracy with respect to late distant recurrence." For women who had not experienced a breast cancer recurrence in five years, Prosigna found that those with low risk scores had a 2.5 percent distant recurrence risk for the next decade and those with high risk scores had a 17.5 percent recurrence risk.
“The ability to stratify patients according to risk of late distant recurrence significantly differentiates the Prosigna Assay from other genomic-based breast cancer assays,” Brad Gray, NanoString CEO, said in a statement. “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.”
Competing breast cancer tests on the market gauge recurrence for five to 10 years after initial diagnosis. With this latest data, researchers have shown that Prosigna may be useful in determining recurrence risk out in patients up to 15 years after initial diagnosis.
As a developer of a second-generation breast cancer recurrence test, NanoString has been preparing for a highly competitive landscape and has tried to cultivate published data around Prosigna with this in mind. In July, researchers from NanoString and elsewhere published data in the Journal of Clinical Oncology showing that the Prosigna score provides more information than Genomic Health's Oncotype DX in gauging the risk of recurrence for women with ER-positive, early stage breast cancer.
However, Oncotype DX has been on the market for a lot longer than Prosigna and is considered the gold standard among prognostic breast cancer tests. Furthermore, Prosigna doesn't have a predictive claim for assessing whether a patient with benefit from chemotherapy treatment, a claim only Oncotype DX has.
“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," senior study author Michael Gnant from the Medical University of Vienna in Austria, said in a statement announcing the latest publication.
In September, the US Food and Drug Administration began offering the test to its customers in January.