One of the largest unmet needs in the amyotrophic lateral sclerosis (ALS) market, is the need to improve diagnosis time; with patients suffering from the disease often missing a formal diagnosis until a year after their initial hospital visit. The reason for this is two-fold; firstly, there is no diagnostic test for ALS, it is diagnosed of exclusion; and secondly, primary and secondary physician’s often will not formally diagnose ALS in patients due to the fatal nature of the disease. They will often leave the formal diagnosis to a specialist working in an ALS clinic.
A typical patient will initially receive an exclusion diagnosis, with a physician running diagnostic tests to rule out other indications and then diagnosing ALS based on the presenting symptoms and signs of the patient. Clinical tests include; magnetic resonance imaging (MRI), electromyogram (EMG), and nerve conduction studies. Often these tests are done in a primary or secondary setting, and the patient is then referred to a tertiary, specialist, clinic for the formal diagnosis.
This process places a huge social burden on the patient; with the time required to diagnosis the disease cutting into the few months that a patient has left. Therefore, this provides a huge opportunity to improve the management of ALS, with earlier diagnosis leading to earlier treatment which is likely to extend lifespan, even if it is just for a few months. One of the research avenues that has been looked into, is the presence of biomarkers which could be used in diagnosis. There are several different types of biomarkers that have been touted as a potential diagnostic tool for ALS, with studies completed and ongoing in microRNA, neuroimaging, blood, and CSF biomarkers.
microRNA’s are small non-coding sections of RNA which regulate gene expression at a post-transcriptional level. A 2016 study looked at miRNA that is specific to muscles (myomiRNA) and found that certain miRNA (miR206, miRNA133a, and miRNA133b) were all upregulated in ALS patients compared to the control group. There is also a growing body of evidence to suggest neuroimaging, which was previously only used to exclude other neuromuscular disorders, has the potential to reveal ALS-specific changes in the brain and spinal cord. Finally, there has been an increase in research in identifying CSF (cerebrospinal fluid) and blood biomarkers which may provide prognostic information, as well as diagnostic.
While this research is still very young it presents the beginning of an ALS specific diagnostic test that has the potential to drastically reduce the amount of time a patient is waiting for a diagnosis, meeting one of the most significant unmet needs in the market. The next steps involve further study into biomarkers, implementing laboratory test early in the diagnostic pathway for ALS patients, and potentially, further expansion into whether they can be used as indicators of therapeutic response.