B-070 Performance Assessment of an Immunoassay for Detection of APOE4 Carriers

Abstract

Abstract Background The APOE gene corresponds to apolipoprotein E, a glycoprotein involved in lipid metabolism. There are three different versions of the APOE gene, e2, e3, and e4 where e3 is the most common allele. APOE4 has been associated with Alzheimer’s Disease (AD) and other neurological diseases. The presence of a single APOE4 allele increases the risk of AD by 3–5 fold and two copies, increase the risk by 8–12 fold. Detection of the APOE4 allele is commonly performed using genetic test methods. Studies were undertaken to evaluate the analytical performance of an immunoassay that detects the presence of APOE4 protein in and assess the discrimination of APOE4 gene carriers from non-APOE4 gene carriers. Methods The Biocross e4Risk® test is a latex agglutination immunoassay used for the quantitative determination of isoform E4 of the apolipoprotein E (APOE4) in human EDTA plasma samples. The test consists of one reagent with latex particles and another reagent with a mouse anti-ApoE4, which induces the latex particle agglutination when ApoE4 is present in the plasma sample. This agglutination is measured photometrically. The turbidity is proportional to APOE4 content of the sample, which can be used to infer the APOE4 genotype responsible. The Biocross kit reagents were run on the Siemens Healthineers Atellica® Chemistry Analyzer (open channel). Stored clinical samples from Eisai’s elenbecestat Phase 3 MissionAD Studies were used in the analysis. Results: Conclusion The Biocross e4Risk® test on the Atellica® Chemistry Analyzer (open channel) demonstrated good analytical performance, with sensitivity and precision comparable to manufacturer’s claims. The assay also had very good sensitivity and specificity when compared to known APOE4 genotype results. A simple blood-based robust APOE4 immunoassay test that runs on a routine clinical chemistry instrument may be a more convenient and cost-effective tool to help recruit patients for AD clinical trial programs.