NEW YORK – After receiving de novo authorization from the US Food and Drug Administration earlier this year, Renalytix is further commercializing its prognostic kidney disease test, KidneyIntelX.
Although it has been offered as a laboratory-developed test since 2020 and has been used by more than 10,000 patients, its FDA approval is clarifying its commercialization path and offering new opportunities for the company, CEO James McCullough said.
The KidneyIntelX immunoassay utilizes three proprietary plasma biomarkers — soluble tumor necrosis factor receptors 1 and 2 and plasma kidney injury molecule-1 — and combines this with clinical data from electronic health records into a machine learning algorithm that generates a risk score. The test is intended for use in patients with type 2 diabetes and early-stage chronic kidney disease and stratifies them based on risk for rapid progressive kidney function decline within five years.
The FDA approval process took upwards of four years, partially due to the redistribution of agency resources resulting from the COVID-19 pandemic, he said, but also because the test's novelty required "a high level of validation [and] an enormous amount of data."
Because of that rigor, the FDA clearance "connotes safe, reliable, and effective advanced prognosis," he said, and gives payors, healthcare providers, and potential commercial partners confidence in the assay. Providing the assay as an LDT allowed the London-based company to learn how to best implement the test in a clinical workflow and begin the reimbursement process, but the new FDA approval will help the company broaden its customer base and insurance network.
The test has already received coverage from Medicare and Blue Cross Blue Shield, among other private payors, and the company expects coverage from additional insurers soon. The growth of its insurance network will also allow the firm to expand its sales force and scale up commercialization, he said.
McCullough also said that Renalytix intends to continue running the test in its CLIA-certified laboratory, rather than manufacturing a commercial kit for use in other laboratories. Running the test in its central laboratory is critical for quality control and consistency, he noted. However, the team is prepared to build laboratory infrastructure internationally if there is significant demand.
Since receiving FDA approval, Renalytix has also seen a "substantial increase" in interest from potential commercial partners in both the US and abroad, McCullough said. The firm already has a distribution partnership in place with Vector Pharma in the Middle East, and McCullough noted that having FDA approval should help the company garner regulatory approval globally. Renalytix has begun seeking such approvals, he added, although 90 percent of its focus is on the US market.
Strategic partners will help market the test and educate clinicians on the benefits of both the test and early-stage kidney disease detection. The company is partnering with both hospitals and insurers to raise awareness of the need for early-stage detection, including Mount Sinai Health System and Atrium Health Wake Forest Baptist Medical Center. Other health system partnerships are in the company's pipeline, as well, he said.
A real-world evidence study published last year with collaborators at Mount Sinai in the Journal of Primary Care and Community Health found that after KidneyIntelX testing there was an increase in visit frequency, referrals for disease management, and introduction to guideline-recommended medications. Those increases varied by risk category, "indicating an impact of KidneyIntelX risk stratification on clinical care," the authors wrote.
According to McCullough, the assay is not necessarily intended for specialist use, although nephrologists, endocrinologists, and cardiologists are using the test. The goal of the company is to put early disease detection technology "in primary care providers' hands," since those providers are seeing diabetic patients in the early stages of disease and prescribing medications that could impact kidney function.
"By the time you get referred to the specialist, you already have advanced disease," he said. Focusing on primary care providers means the company is "working on the front end … where drugs and clinical intervention have the most effect."
One of those primary care providers is Sherry Howard, a nurse practitioner at Providence Medical Group who has used KidneyIntelX for more than a year. She currently uses it on diabetic patients who have already had routine laboratory tests performed. Previously, she would base medications on just the results from those tests, such as glomerular filtration rate and microalbumin concentration. However, Howard said she has used KidneyIntelX with multiple patients who had normal routine results and discovered they had higher risk for severe disease, which caused her to change their medications.
In addition to medication management, the test also works well as a teaching tool for patients, she said, since the results are easy to understand and the test helps them avoid having to see a specialist.
One downside Howard noted is the cost, as some patients have had to pay out of pocket for the test, which is currently priced at $950 by Medicare. She also emphasized the need to expand indicated use guidelines, since there are patients who don't meet the requirements for testing but who could still be at higher risk for dialysis.
Renalytix has multiple plans for broadening its test beyond its original indication. Along with building data for the current indicated use of the test, the company is also looking into new biomarkers and improvements in its algorithm to further boost performance of the assay and expand its indicated use. The firm focused on patients with diabetes first "because they tend to have the biggest contribution to uncontrolled progression of kidney disease," McCullough said.
But now that it understands the FDA process and has approval, Renalytix is also investigating potential new components, such as cardiovascular markers, and applying the test to other populations. The firm is involved with a variety of research projects surrounding new biomarkers and is determining how new biomarkers can best be deployed in different use cases, he said.
It is also interested in measuring therapeutic response and providing an "accurate gateway to understand who should get what drugs," he added.
Ultimately, the company's goal is to reach a point where its test is able to "understand not only the risk for progression but the characterization of that disease," including therapeutic response and mechanism of action, he said.