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Study Shows NanoString's Prosigna Test Predicts Chemo Benefit as Firm Targets Immuno-oncology Growth


NEW YORK (GenomeWeb) – NanoString Technologies last week announced the publication of a retrospective study showing that its Prosigna breast cancer diagnostic test was able to predict which patients would respond to neoadjuvant chemotherapy.

"It's the first time that Prosigna has been able to predict chemotherapy benefit in early-stage breast cancer," NanoString CEO Brad Gray told GenomeWeb.

The study also is the first of what Gray thinks will be a series of publications showing the benefits of the test, with more publications to come out of data first presented at the American Society of Clinical Oncology conference earlier this year.

"The result of the study helps continue to strengthen the evidence for clinical utility of Prosigna," Gray said. "It will be useful in our conversations with payers, as we continue to seek reimbursement, and with guidelines committees and key opinion leaders who are helping to define where Prosigna sits within the guidelines."

The retrospective study of 122 samples from Spain, published last week in Clinical Cancer Research, analyzed whether Prosigna could identify high-risk breast cancer patients who might respond to chemotherapy.

The Prosigna assay runs on NanoString's nCounter platform and yields a recurrence score based on the PAM50 gene signature; the score denotes the risk that a woman's breast cancer will recur 10 years after diagnosis. The US Food and Drug Administration first cleared the test in 2013, and updated its label last December to provide additional information on the risk of 10-year distant recurrence.

The test had already demonstrated an ability to identify low-risk patients who could be spared the toxicity of chemotherapy, Gray said. And, generally, other studies have shown that high-risk patients tend to respond to chemotherapy, and those whose tumors shrink in response to therapy tend to live longer.

The results of the Prosigna study were encouraging. The data suggested that Prosigna risk scores, as well as the intrinsic subtype of tumor as defined by the algorithm in the test's bioinformatics package, were able to predict whether the patient responded to chemotherapy.

Being a retrospective study, the researchers won't be able to follow patients for several years to get that data, but NanoString could look to perform such a study in the future. Gray said it was too early to specify how the firm would follow up on the study, but he noted that the firm had presented data from four other studies at the recent ASCO conference that could make their way into the literature.

One potential use for Prosigna is to identify patients whose tumors are node positive at an early stage, but who remain very low risk and thus may be able to avoid chemotherapy. Another is to identify patients who survive for five years but remain at risk for recurrence. "It's important for those patients to extend adjuvant endocrine therapy beyond five years," Gray said.

The recently published paper and the papers that could come out of the data presented at ASCO could help NanoString as it continues to try and penetrate the market by garnering reimbursement from payers and getting Prosigna included in treatment guidelines.

"We're off to a good start," with payers, Gray said, "but still have a long way to go."

UnitedHealth became the first major US-based payer in August 2014, and in May CMS issued a positive draft local coverage decision for Prosigna.

Gray said NanoString is now shifting its attention to other major private payers, such as Aetna and Humana.

The recent study could also help get Prosigna included in the National Comprehensive Cancer Network guidelines. NanoString had already made a submission for the test to be included in the next update, but Gray said the submission would be updated to include the new paper.

In March, the German Association of Gynecological Oncology acknowledged Prosigna in its treatment guidelines, and in May the St. Gallen International Breast Cancer Guidelines did the same.

Gray said the studies wouldn't expand the market for the test, but should help to drive adoption within the existing market.

Focus on immuno-oncology

With Prosigna making up only 3 percent of the firm's first quarter revenues, Gray was quick to point out how NanoString was focusing on the immuno-oncology market.

During the first half of the year, the firm has launched new oncology research products; signed research partnerships with MD Anderson Cancer Center, the Cancer Immunotherapy Trials Network, and Merck; and hired a new chief medical officer with an extensive background in immuno-oncology.

The research collaboration with Merck to develop a companion diagnostic for the anti-PD-1 therapy Keytruda (pembrolizumab) was inked in May. The relationship started, Gray said, when Merck purchased NanoString's nCounter technology as a customer. "They used our tech to discover new biomarkers. When they succeeded, they came to us to develop them as diagnostics."

Gray also noted that NanoString has hired Alessandra Cesano as chief medical officer. Cesano has a doctoral degree in tumor immunology from the University of Turin and has 25 years of experience in drug development, diagnostics, and cancer immunology, including stints at Biogen Idec, Amgen, and SmithKline Beecham Pharmaceuticals.

In addition, in the upcoming months, NanoString will launch an early-access program for a new RNA/protein assay, which Gray said will let researchers measure both gene and protein expression in the same experiment.

"It's about getting more info from the tiny samples we have available and not having to choose between genomics versus proteomics," Gray said.