Nearly three years in the making, Renalytix has finally reeled in the FDA’s authorization for its prognostic test aimed at predicting an oncoming decline in kidney function.
The U.K.-based company first submitted the KidneyIntelX test platform to the FDA for review in August 2020, about a year after it had earned the agency’s breakthrough-device designation for the technology.
During a presentation at the annual J.P. Morgan Healthcare Conference in January of last year, Renalytix CEO James McCullough commented on the drawn-out review process, saying of the FDA, “We know they’re working hard down there, and they’re overwhelmed. I sympathize with them, but we are making progress there, and we expect to have that in 2022.”
That timeline was later pushed to the first quarter of this year and then, in a March update from the company, to the second quarter—a goal that Renalytix just barely met with its announcement of the de novo clearance last week.
A month after the initial submission, Renalytix launched KidneyIntelX as a laboratory-developed test (LDT), allowing it to bypass FDA clearance as long as it was made and used in a single lab. The LDT launch began at New York City’s Mount Sinai Health System, which is where the technology behind the KidneyIntelX test was first developed before being licensed to Renalytix.
In the years since that rollout began, the LDT version of the test has been used on about 10,000 U.S. patients, according to the company.
Now that the FDA has handed down de novo clearance to the test, it’ll still be available as an LDT under the KidneyIntelX name but will also be more widely commercially available as the FDA-cleared KidneyIntelX.dkd. The added suffix stands for diabetic kidney disease, a form of chronic kidney disease that’s specifically caused by diabetes—which itself is the most common cause of kidney disease, according to the National Institutes of Health.
The KidneyIntelX.dkd test relies on an artificial intelligence algorithm to look for certain biomarkers in a patient’s blood sample and to analyze a handful of additional data points collected in their electronic health record. The AI’s findings are presented as a risk score that suggests whether an individual patient is at a low, moderate or high risk of experiencing a progressive decline in kidney function within the next five years.
One study (PDF) published in early 2021 showed that KidneyIntelX correctly predicted declining kidney function with an area under the curve of 0.77, compared to an AUC of 0.61 for a traditionally used clinical model.
The test is currently aimed at predicting declining kidney function in people with Type 2 diabetes and early-stage chronic kidney disease, but McCullough suggested in the announcement that the newly bestowed FDA clearance could open new doors for Renalytix’s technology.
“With this approval, a new class, ‘Prognostic Test for Assessment of Chronic Kidney Disease Progression,’ has been established by the FDA, providing a roadmap for future expansion of KidneyIntelX into new indications and products,” the CEO said.