FDA Approves First Blood-Based Alzheimer's Test, Potentially Boosting Leqembi's Market Prospects

The U.S. Food and Drug Administration (FDA) has approved the first blood-based test for diagnosing Alzheimer's disease, marking a significant milestone in the field of neurodegenerative disorders. This development could have far-reaching implications for the pharmaceutical industry, particularly for companies like Eisai and Biogen, which are marketing the Alzheimer's treatment Leqembi.

Fujirebio's Lumipulse Test: A Game-Changer in Alzheimer's Diagnosis

Fujirebio Diagnostics' Lumipulse test received FDA approval on May 19, 2025, offering a less invasive alternative to current diagnostic methods. The biomarker test measures the plasma ratio between pTau217 and beta amyloid 1-42 to detect amyloid plaques, which are targeted by treatments such as Leqembi and Eli Lilly's Kisunla.

The Lumipulse test demonstrated impressive accuracy in clinical trials, with a positive predictive value of 91.7% and a negative predictive value of 97.3%. These high scores indicate a low rate of false positives and false negatives, respectively. However, the FDA has emphasized that the test is not intended as a standalone diagnostic tool and should be used in conjunction with other clinical evaluations.

Implications for Leqembi and the Alzheimer's Treatment Landscape

The approval of Lumipulse could potentially accelerate the adoption of Leqembi, which has faced a somewhat tepid market reaction since its launch. Eisai and Biogen have identified more convenient diagnosis and administration as key factors for driving Leqembi's long-term growth.

Currently, doctors rely on amyloid PET scans or cerebrospinal fluid (CSF) tests to confirm the presence of amyloid plaques before prescribing Leqembi. These methods are costly, time-consuming, and invasive, limiting their availability and potentially hindering Leqembi's rollout.

Mizuho analyst Salim Syed suggests that while the Lumipulse approval is welcome news for the Alzheimer's space, factors such as payer reimbursement and physician adoption will play crucial roles in determining its impact on Leqembi's sales. Syed notes that the blood-based test could be particularly useful as a "rule-out" test, potentially freeing up resources by triaging ineligible patients before more invasive testing is required.

Challenges and Future Outlook

Despite the potential benefits of the Lumipulse test, several challenges remain. Physicians may require education on its use and interpretation, particularly if it is to replace PET and CSF tests in some cases. Additionally, reimbursement will be a critical factor in the test's widespread adoption.

Eisai recorded 26.1 billion Japanese yen ($171 million) in U.S. Leqembi revenue for the 12 months ending March 2025, with a forecast of 40 billion Japanese yen for the following fiscal year. The company, along with partner Biogen, is banking on advancements like blood-based diagnostics and a subcutaneous drug formulation to drive Leqembi's growth in the coming years.

As the pharmaceutical industry continues to focus on Alzheimer's treatments, the approval of Fujirebio's Lumipulse test represents a significant step forward in improving diagnosis and potentially expanding access to therapies like Leqembi. However, the full impact of this development on the market remains to be seen, as stakeholders navigate the complexities of implementation, reimbursement, and clinical practice.