Home » Dementia » Predicting the risk of cognitive decline in Alzheimer’s

Dr Richard Pither

CEO, Cytox

Addressing challenges seen in patient care and new drug development

Some of the greatest challenges in treating Alzheimer’s disease (AD) are determining who is at risk of getting the disease and knowing when they are likely to experience cognitive decline. These unknowns have a major impact on two key groups of experts operating in AD healthcare: firstly, those patient-facing clinicians seeking to improve therapy and patient outcomes; secondly, clinicians involved in clinical studies to develop new AD drugs.

How patient facing clinicians would benefit from predicting AD

Patient-facing clinicians tend only to see patients once symptoms have started or are quite well progressed, when cognitive therapies and lifestyle changes will have less impact. It is currently not possible to assess patients for the risk of AD, before symptoms arise, without the use of highly invasive or expensive tests. Furthermore, such clinicians cannot provide much insight into the potential future onset of AD in people who have family members with the disease, including the so-called worried well.

How clinical studies would benefit from predicting AD

Clinicians conducting clinical studies have different challenges. Ideally, patient recruitment to studies would only select those at highest risk of significant cognitive decline due to AD over the period of the study. In this scenario, any efficacy of the drug under assessment would be easily observed if the anticipated cognitive decline is prevented or delayed. However, the current diagnostic and disease analysis techniques used to recruit such patients – those most at risk of near-term cognitive decline – have significant shortfalls.

Reporting beyond ApoE

Many tests currently available report on ApoE status. However, while this is a major component of risk, especially carriers of the -E4 allele, there is a need for greater granularity on the risk of cognitive decline within the E4 heterozygote and E3 homozygote populations, which make up around 80% of the Caucasian population.

Enabling clinicians

A new test to address these issues is on the near horizon. This test would enable clinicians to make more informed decisions about their patients and what additional, more expensive and intrusive, tests may be of use. And while there are no disease modifying drugs available to treat AD, Biogen’s product currently under priority review at the US FDA may become available in 2021, if approved. The so-called worried well can potentially be put at ease; and in those individuals where there is a risk of disease and cognitive decline, and drug therapy is not available there are lifestyle options including exercise, cognitive training, changes to diet that could significantly reduce their risk.

Those people who are at a high risk of cognitive decline in the near term, have the greatest opportunity to benefit from developmental drugs in clinical studies, and can make such decisions alongside their clinician.

A new test from Cytox, genoSCORE™, aims to address these issues. The test (to be launched in late 2020) is a genetic test, using a blood or saliva sample, that analyses patient genotypes against an array of about 114,000 single nucleotide polymorphisms (SNPs) that have been associated with AD. As such, the test generates a polygenic risk score (PRS), which is a patient-specific genotypic analysis designed to predict the risk of future onset of AD.

Cytox anticipates the test being used as a non-invasive, easy-to-use, test that will form part of the initial assessment made when first seeing patients, in addition to providing further insight to existing patients. If required, its simplicity of use would enable elderly and vulnerable patients, self-isolating or not wishing to attend healthcare settings due to COVID-19, to provide a suitable sample from home.

With a turnaround time of two to four weeks, the genoSCORE report (see chart below) will show where a patient lies on the scale of risk (compared to the population as a whole), how that risk increases with age, and can predict when an individual will fall into a higher risk category for AD.

To subscribe for future information about genoSCORE, click here.

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