Development of a peptide-based diagnostic for amyotrophic lateral sclerosis - SUMMARY/ABSTRACT
Amyotrophic lateral sclerosis (i.e. ALS or Lou Gehrig's disease) is the most common adult-onset motor neuron
disorder, with progressive weakness being the clinical hallmark. The average survival rate is 2-5 years post-
diagnosis, but 10% of individuals survive ≥10 years, due to highly variable rates of progression. There is no cure
for ALS, but there are treatments and interventions that can limit symptoms and unnecessary complications, and
improve quality of life. Unfortunately, there is no single definitive diagnostic for ALS or validated biomarker for
disease progression. It takes nearly a year from the first occurrence of symptoms to confirm ALS in most patients
using current approaches (e.g. MRI, nerve function analyses, multiple blood and urine tests to rule out mimic
disorders). Also, the only validated markers of disease progression are time to death and the Revised ALS
Functional Rating Scale (ALSFRS-R), which is a subjective measure of disability and breathing. Although ALS
is a rare disease (affecting approximately 20,000 people in the US), many more prevalent diseases can mimic
ALS including but not limited to peripheral neuropathies, multiple sclerosis, neuromuscular transmission
disorders, and hyperthyroidism. Significantly, up to 61% of ALS patients are misdiagnosed with a mimic disorder
initially, which can negatively impact patient outcomes. There is an urgent unmet need to diagnose ALS at earlier
timepoints via rapid and non-invasive methods, and to objectively predict ALS progression, particularly in the
clinical trial setting. ALS-associated antibodies offer a new avenue for ALS diagnostics and disease monitoring.
While previous studies measuring total levels of humoral antibody types (IgG, IgA, and IgM) have been
inconsistent, recent studies have identified specific IgG autoantibodies, independent of absolute IgG level, as
potential new markers of sporadic ALS onset and progression. Based on these recent findings, we propose to
identify a sensitive and selective immunosignature, which we will develop into a reliable, non-invasive,
in vitro array for the early detection of ALS. This array may also have potential for monitoring and
predicting disease progression.
In this Phase 1 application, we will use phage display biopanning and next generation sequencing to identify
peptides that bind antibodies specifically enriched in patients with sporadic ALS and develop a peptide array
capable of reproducibly detecting this immunosignature from serum. In Phase 2, we will refine the
immunosignature for the early detection of ALS at baseline and additional timepoints, assess utility of the array
to determine progression of the disease, and scale up array production. This simple peptide-based test will
provide clear and actionable results for primary care physicians and neurologists, allowing the definitive and
rapid diagnosis of ALS, thereby increasing the rate of early detection, diagnosis, and proper management. This
test also has potential to enable the serum-based prediction of disease progression.