technicians can perform the diagnostic test themselves on site.
Here’s how the study worked: NanoString obtained 1,017 tumor samples taken from women in England who enrolled in the landmark study known as ATAC, and got acceptable results from 1,007 of them. The women had early-stage breast cancer, and were treated a couple different ways. They were followed up for 10 years, and records exist on how many of them ended up having recurrences or not.
NanoString analyzed the tumor samples with its 50-gene signature in about six weeks at its Seattle labs, in September and October, Gray says. Based on what the machine said, NanoString classified women as either low, intermediate, or high risk, just like how Genomic Health validated its Oncotype DX breast cancer test, Gray says. Once the data was gathered, researchers then compared the NanoString predictions for each individual with what records showed actually happened.
The NanoString and Genomic Health tests were almost the same when it came to classifying women as “low” risk, as the NanoString machine put 428 women in that camp, and Genomic Health’s test classified 434 women that way, Gray says. But the big difference was in the “intermediate” and “high” risk groups. NanoString’s test put 192 women in the “intermediate” gray zone, while 243 women were put in that group by Genomic Health, Gray says.
Mitch Dowsett, a breast cancer researcher at The Royal Marsden Hospital and The Institute of Cancer Research in London, and the lead investigator working with NanoString, said in a statement: “In the 1,007 samples for which results from both tests are available, the NanoString PAM50 ROR score provided significantly more prognostic information than the Oncotype DX RS score and assigned fewer patients to the intermediate risk group than Oncotype DX,” test from Genomic Health.
The data wasn’t made available in advance to conference organizers, as it usually is, and it wasn’t summarized in abstracts beforehand, so people were clearly processing the information for the first time as they heard it live this afternoon in San Antonio. In an unusual move, conference organizers agreed to showcase the study results before the data even existed, because of their strong interest in the design of the study, and the information it might yield, Gray says.
“What we saw was that PAM50 is a very accurate predictor of whether women will or will not recur,” Gray says.
Steve Shak, Genomic Health’s chief medical officer, offered the following statement tonight on the new data from NanoString: “While this is interesting early, prognostic data, it needs to be replicated to demonstrate predictive value and in order to be applied to clinical practice. Oncotype DX is the only test that has clinical evidence validating its ability to predict the likelihood of chemotherapy benefit as well recurrence in early stage breast cancer.”
NanoString designed this study so that it could stand on its own as part of an application for regulatory approval to start selling its test in certain parts of the world, such as the European Union, Gray says. More data from another trial will likely be needed before NanoString attempts to seek U.S. approval from the FDA, he says. But because these trials are retrospective—meaning they depend on getting samples and records on patients that enrolled in past studies—they can be done more quickly than so-called “prospective” studies which would require recruiting and enrolling more than a thousand new patients and then following them up for years to see if they have recurrences.
Gray declined to offer a timeline for when the next study can get started and finished, and he didn’t say when the company wants to turn in its application to the FDA. But he did note that NanoString’s first meeting with the principal investigator of today’s study was only one year ago at the same San Antonio conference, and it only took the company six weeks to go from processing its first tumor sample to generating the data on the accuracy of its predictions.
“We’d like to go a little further down the path before committing to timeline,” Gray says. But he added, “we’re working as diligently as we possibly can on our second act.”
