The first in vitro diagnostic tool to help detect early Alzheimer's disease was on Wednesday.
The assay measures the ratio of beta-amyloid 1-42 to beta-amyloid 1-40 in cerebrospinal fluid (CSF). The Lumipulse G ß-Amyloid Ratio (1-42/1-40) test is intended to be used in adults 55 and older presenting with cognitive impairment who are being evaluated for Alzheimer's disease or other causes of cognitive decline.
Test results are consistent with amyloid PET scan results, the agency noted.
"The availability of an in vitro diagnostic test that can potentially eliminate the need for time-consuming and expensive PET scans is great news for individuals and families concerned with the possibility of an Alzheimer's disease diagnosis," said Jeff Shuren, MD, JD, director of the FDA's Center for Devices and Radiological Health, in a statement.
"With the Lumipulse test, there is a new option that can typically be completed the same day and can give doctors the same information regarding brain amyloid status, without the radiation risk, to help determine if a patient's cognitive impairment is due to Alzheimer's disease," Shuren added.
The FDA evaluated the safety and effectiveness of the Lumipulse test in a clinical study of 292 CSF samples from the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort, which were compared with amyloid PET scan results.
Overall, 97% of ADNI participants with positive Lumipulse results had the presence of amyloid plaques on PET, and 84% of individuals with negative Lumipulse results had a negative amyloid scan, the agency said.
Risks associated with the test include the possibility of false positive or false negative results. "Importantly, the Lumipulse G β-amyloid Ratio (1-42/1-40) is not a stand-alone test and other clinical evaluations or additional tests should be used for determining treatment options," the FDA pointed out.
There's an unmet need for a reliable, safe test to identify patients with amyloid plaques consistent with Alzheimer's disease, the agency added. Amyloid plaques can occur in other diseases but being able to detect their presence, along with other evaluations, can help clinicians determine the probable cause of a patient's symptoms.
Much research in recent years has focused on blood as a new matrix for Alzheimer's biomarkers that already have been validated in CSF. A blood test for amyloid-beta has been widely available in the U.S. since 2020 under a CMS certification process for laboratories that tests patient samples, but is not yet FDA-approved.
FDA permitted marketing of the Lumipulse G ß-Amyloid Ratio (1-42/1-40) test to Fujirebio Diagnostics. The agency reviewed the assay through its premarket review pathway. This action creates a new regulatory classification, which means that subsequent devices of the same type with the same intended use can obtain marketing authorization by demonstrating substantial equivalence to a predicate device.