Diagnostic aptamer reagents to develop multi-analyte blood test for pre-clinical, mild and moderate Alzheimer's disease

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Diagnostic aptamer reagents to develop multi-analyte blood test for pre-clinical, mild and moderate Alzheimer’s disease Aptus Biosciences, LLC Bharat Gawande Summary Today, 6.2 million Americans are living with Alzheimer’s disease (AD), resulting in $355 billion in annual medical care costs. As the US population over age 65 grows, the number of Americans living with AD is expected to increase to 12.7 million by 2050. AD is a slow progressing disease, and it may take up to 20 years before symptoms are recognizable. While new treatments are emerging, that may help to control or modify the disease, early detection using a simple blood test is critical to individuals with AD. Importantly, recent studies have shown promising results with blood-based biomarkers that are specific for AD. However, there is clearly a lack of high affinity reagents that can bind to these biomarkers and be used to develop sensitive and easily accessible blood tests. Aptus Biosciences will use modified aptamer selection technology, to create highly sensitive and specific reagents that detect blood biomarkers of AD which cause neurofibrillary tangles (NFTs), a hallmark of AD. We will deliver aptamer reagents developed from an improvised In Vitro selection method using hydrophobic modified nucleotides that can bind to tau protein, and multiple isoforms of phosphorylated tau (p-tau) protein with pico-molar affinity. Each targeted selection will generate aptamers that bind to various epitopes on specific p-tau targets with picomolar affinity and that will be used to develop a simple bead-based aptamer sandwich assay in which one aptamer will capture p-tau biomarker and other aptamer will result in a signal generation to measure the plasma concentrations of these analytes. Our modified aptamer reagents are potentially better than unmodified aptamers and large antibody-based reagents, which are not as sensitive or specific because of their large size, low affinity, and cross-reactivity in multi-analyte assays. Specifically, we will use selections to create modified aptamers that bind to specific validated phosphorylated isoforms of tau. In addition, we will develop a simple bead-based multi-analyte aptamer sandwich assay to measure p-tau isoforms in plasma samples obtained from cerebrospinal fluid (CSF) Aβ42 positive, AD-confirmed individuals and compare them with plasma samples obtained from cognitively normal, Aβ42 negative individuals without AD. If this Phase I grant is successful, in Phase II, we will optimize aptamer reagents to improve the sensitivity and specificity of the assay, scale-up aptamer reagent production, develop a cloud-based algorithm using a training sample set, and validate the assay using test samples to correctly identify early AD in a large cohort. The multi- analyte aptamer-based assay will make it far superior to existing qualitative, invasive, and expensive diagnostic tests. If successful, this simple blood test will enhance the lives of millions of Americans who are at high risk of developing AD due to the ability of the test for early detection, thus resulting in early treatment interventions and decreasing the huge economic burden to the healthcare system.