Blood-Based PCR Test Guides Alzheimer's Therapy

Alzheimer's disease (AD) appears in various forms, and diagnostic imaging techniques are used to assess the presence and severity of senile plaques, which are primarily made up of amyloid beta (Aβ) protein. These plaques can disrupt the supply to nerve cells, leading to their degeneration and death. In recent years, AD research has focused on the development of monoclonal antibodies (mAbs) targeting Aβ plaques to facilitate treatment. However, clinical trials have shown that using anti-Aβ antibodies can sometimes cause amyloid-related imaging abnormalities (ARIA), which may be life-threatening. The risk of developing ARIA from anti-Aβ antibody treatment varies according to a patient's apolipoprotein E (APOE) gene genotype. Those with the ԑ4/ԑ4 genotype face a higher risk, while individuals with the ԑ2/ԑ4 and ԑ3/ԑ4 genotypes have a slightly elevated risk. Therefore, genotyping is crucial for assessing this risk. A new PCR-based test for determining APOE genotypes can assist in the proactive evaluation of risk factors for AD patients undergoing anti-Aβ antibody treatment. This assay allows for quick and easy identification of APOE gene variants ε2, ε3, and ε4 in a single test.

Revvity’s (Waltham, MA, USA) in-vitro diagnostic EURORealTime APOE assay provides precise genotyping of the APOE gene. With this new test from Revvity’s EUROIMMUN (Lübeck, Germany), only one reaction is needed using genomic DNA from a single blood sample to determine the patient’s APOE genotype. The real-time EURORealTime APOE PCR test detects the three most common APOE forms—ε2, ε3, and ε4—simultaneously. The test can be automated to varying degrees using Revvity’s instruments, such as the EUROIMMUN PreNAT II and the chemagic 360 platforms. The results are analyzed, documented, and archived using EURORealTime analysis software. This genotyping approach offers clinicians valuable patient-specific information, allowing for a more personalized strategy in administering anti-Aβ treatments. The EURORealTime APOE assay is available in European countries that accept the CE mark.

“With the introduction of new disease-modifying drugs for treating Alzheimer’s, a new era of therapy has begun for this incurable disease. However, it has been found that patients taking these treatments with a certain form of the APOE gene have a significant risk for developing potentially life-threatening side effects, called ARIA, referring to edema or microbleedings in the brain,” said Dr. Lars Komorowski, chief scientific officer of EUROIMMUN. “Being able to easily determine the APOE genotype of patients before starting therapy is key to assessing the individual risk for potential negative consequences.”

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