New Blood Check Transforms Alzheimer’s Detection

Traditional Alzheimer’s disease diagnostics leave many undiagnosed until their symptoms are advanced. The creators of a noninvasive blood biomarker test hope to change that.

Diagnosing Alzheimer’s disease has long relied on expensive and invasive procedures, often delaying care until symptoms are well advanced. With the recent US Food and Drug Administration (FDA) clearance of Fujirebio’s Lumipulse G pTau 217/β-Amyloid 1-42 Plasma Ratio test, clinicians now have access to a simpler, blood-based diagnostic tool for identifying amyloid pathology.

In this Innovation Spotlight, Diana Dickson, the vice president of Clinical and Regulatory Sciences at Fujirebio Diagnostics, talks about the challenges surrounding Alzheimer’s disease diagnosis and highlights what the FDA’s clearance of the Lumipulse blood test will mean for patients.

What are the challenges associated with current Alzheimer’s disease diagnostics, and how does this affect patients?

Alzheimer’s disease is very challenging to diagnose, so there is a great need for more diagnostic tools, such as in vitro diagnostic clinical blood tests. Alzheimer’s disease develops over many years, long before symptoms are evident. The lack of accessible, minimally invasive diagnostics results in many patients remaining undiagnosed until the disease is well advanced. In addition, while being the most common form of dementia, it’s not the only cause of cognitive decline, further compounding the need for efficient diagnosis. We know that around 7 million people in the United States are affected by the disease today, and this number is going to double in our lifetime, which is a scary statistic. We need to continually do better to get ahead of this horrible disease.

Not having easy access to a test can prevent a patient from being considered for one of the newly emerging Alzheimer’s disease therapies. The recent FDA-approved Alzheimer’s disease therapies^1,2 require proof of amyloid pathology—a hallmark of Alzheimer’s disease—before treatment. Prior to the FDA clearance of Fujirebio’s Lumipulse G pTau 217/β-Amyloid 1-42 Plasma Ratio test, brain imaging and spinal fluid testing were the FDA-approved diagnostic tools used to identify amyloid pathology. For brain imaging, amyloid positron emission tomography (PET) scans require that patients be injected with a radioactive tracer and lie still in a scanner for 15 to 20 minutes. For the spinal fluid testing, cerebrospinal fluid (CSF) is collected via lumbar puncture or spinal taps, which are invasive and can leave patients with a headache or back pain. Both tests are expensive and hard to access for some patients. Conversely, the Lumipulse test only requires a simple blood draw, making it less invasive and much easier for patients to access.

How does the new Lumipulse diagnostic test work, and why is its FDA approval so significant?

The Lumipulse G pTau 217/β-Amyloid 1-42 Plasma Ratio test works by measuring two biomarkers in the blood, pTau 217 and β-amyloid 1-42, in the form of a ratio. These biomarkers reflect the biological changes associated with Alzheimer’s disease occurring in the brain. When a patient has signs and symptoms based on neurological examinations consistent with Alzheimer’s disease, this new blood test can reliably predict the presence or absence of amyloid pathology associated with Alzheimer’s disease, becoming an important piece of the patient’s diagnostic evaluation. It can help physicians determine whether further testing or treatment for Alzheimer’s disease is warranted.

The Lumipulse blood test was determined by the FDA to be substantially equivalent to amyloid PET brain scans and CSF tests, both FDA-approved test methods. This was demonstrated by performing a robust clinical validation study of 499 patients, who were 50 years old and above, reflecting the US demographic population, with cognitive impairment ranging from early stages of disease to later stages. In the study, positive Lumipulse test results were consistent with patients having amyloid pathology, and negative results meant that a patient’s cognitive symptoms were unlikely due to amyloid pathology. We saw fewer than 20 percent of patients with uncertain test results, who would require further testing and evaluation to determine whether one has amyloid pathology. It is important to note that all test results must be interpreted in conjunction with other patient clinical information. This FDA clearance marks the first blood test to aid in the assessment of amyloid pathology associated with Alzheimer’s disease as soon as a patient is showing signs and symptoms of cognitive decline.

Continue reading below…

How reliable is this test in a clinical setting?

When diagnostic manufacturers design and develop tests for clinical use, we must ensure that our products can provide accurate results in various laboratory settings across the country and, in many cases, globally, and are robust enough to maintain their performance characteristics under a range of operating conditions in different laboratory environments. We do this in a variety of ways, including developing precise instrument systems, ensuring our tests are safe and effective for their intended use, and complying with all regulatory requirements, including FDA regulations.

In our clinical performance study, using the ratio of the two biomarkers correctly classified more patients into positive and negative test results by reducing the number of patients falling into the uncertain zone, compared to only measuring one biomarker. We believe this helps offset any one biomarker being affected by a patient’s co-existing medical condition, medications, age, or ethnic or racial impacts. In addition, we provide detailed instructions for use to ensure optimal results, including for instrument operation, blood sample handling, and result interpretation.

How quickly can clinical laboratories integrate this test into routine practice?

Our test is available now in various clinical laboratories around the US, including the largest reference laboratories. The Lumipulse test is required to be run in High Complexity CLIA-certified laboratories, and the timing for introduction by a laboratory would depend on their individual processes. Generally, it takes a few weeks for the laboratory to go through internal validation, update the laboratory information system, and integrate the test into their reporting system. We support this integration by providing on-site, hands-on training, educational tools, and frequent communication. We encourage laboratories to reach out with any questions they may have.

What does the future hold for blood-based biomarker tests?

This is the culmination of over 30 years of commitment by Fujirebio in the fight against Alzheimer’s disease. The battle is not nearly over. There is much work to be done not only with this test but also in the development of novel biomarkers for use in other neurodegenerative diseases and related pathologies.

We continue to be committed to these efforts and are immensely grateful for the partnerships with the pharmaceutical, research, and patient communities that have made and continue to make these advances possible. It is important for us to remain actively engaged in the clinical community to spread awareness of our test, how it should and should not be used, and how results are best interpreted in a clinical context.