Dive Brief:

• The Food and Drug Administration cleared a blood test that measures biomarkers to inform the diagnosis of Alzheimer’s disease, the agency said Friday.
• Fujirebio Diagnostics received the 510(k) clearance, which the FDA said is the first of its kind, after showing its blood test is substantially equivalent to an existing diagnostic that uses samples collected through an invasive lumbar puncture, also known as a spinal tap.
• Labcorp and Quest Diagnostics began selling laboratory-developed tests for the same biomarkers earlier this year. Executives at Eisai, the manufacturer of an Alzheimer’s drug, said on an earnings call last week that triage testing using blood-based biomarkers “is dramatically increasing.”

Dive Insight:

The presence of amyloid plaques in the brain is a sign that a patient with cognitive impairment could have Alzheimer’s, making PET scans the gold standard for diagnosis. Cerebrospinal fluid tests that compare the ratio of two proteins, pTau217 and beta-amyloid 1-42, can cut the need for PET scans, but the diagnostics rely on samples collected via a lumbar puncture. 

Blood tests could be more accessible and scalable than CSF diagnostics and PET scans. The approval of disease-modifying drugs such as Eisai and Biogen’s Leqembi and Eli Lilly’s Kisunla has increased interest in tests that can help physicians accelerate the diagnosis of Alzheimer’s.

Fujirebio, a Japanese diagnostics company, has given physicians a new testing option by securing 510(k) clearance for its Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio. The FDA cleared the test for the early detection of amyloid plaques associated with Alzheimer’s in people aged 55 years and older with signs and symptoms of the disease.

The blood test is substantially equivalent to a Lumipulse CSF test. Fujirebio compared the blood test to PET scans and CSF results in a multi-center clinical study of 499 plasma samples from adults who were cognitively impaired. 

Fujirebio found 91.7% of people who tested positive on the blood test had amyloid plaques by PET scan or CSF test result. The trial showed 97.3% of individuals with negative blood test results had a negative amyloid PET scan or CSF test result. The FDA said less than 20% of patients received an indeterminate Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio result.

“These findings indicate that the new blood test can reliably predict the presence or absence of amyloid pathology associated with Alzheimer’s disease at the time of the test in patients who are cognitively impaired,” the FDA said in a statement. “The test is intended for patients presenting at a specialized care setting with signs and symptoms of cognitive decline.”

Physicians must interpret the results in conjunction with other patient clinical information, the FDA said. The agency added that the test “is not intended as a screening or stand-alone diagnostic test and other clinical evaluations or additional tests should be used for determining treatment options.”

To date, blood tests have been limited to triaging patients. People who test negative on a blood test are unlikely to have amyloid plaques and, as such, may be able to skip invasive CSF tests and expensive PET scans. Eisai identified regulatory authorizations, Medicare reimbursement and upcoming guidelines from the Alzheimer's Association as key steps toward the use of blood tests to confirm Alzheimer’s diagnosis.

“Alzheimer’s disease impacts too many people, more than breast cancer and prostate cancer combined,” FDA Commissioner Martin Makary said in a statement. “Knowing that 10% of people aged 65 and older have Alzheimer's, and that by 2050 that number is expected to double, I am hopeful that new medical products such as this one will help patients.”