Repetition Is Key

Amyotrophic lateral sclerosis (ALS) is a fatal degenerative disease of the central nervous system. Accurate, early diagnosis is crucial with all diseases because it enables early intervention and, sometimes, more favorable outcomes – but this holds particularly true for ALS. The typical time between symptom onset and diagnosis is about one year and, given that mean survival time with ALS is two to five years, any delay in diagnosing a patient can have a critical impact. Furthermore, it is estimated that up to 44 percent of patients initially receive a false negative diagnosis (1).

In 2020, researchers identified a microRNA fingerprint from extracellular vesicles that successfully diagnosed early-stage ALS (2) – but were the findings replicable? To find out, the same team conducted a new experiment using the eight previously defined biomarkers, but in different ALS populations and with less stringent plasma collection and storage parameters (3). Using blood samples from 50 ALS patients and 50 control participants, they found that five of the microRNA biomarkers successfully distinguished ALS patient samples from healthy controls – an indicator that the method is a repeatable measure for detecting ALS. “We were surprised that the microRNA test worked for samples collected from a variety of investigators under differing conditions,” said first author Sandra Banack (4).

The researchers also expected that samples would need to be collected and stored under strict conditions like those of the first study. However, lead author Paul Alan Cox noted that “apparently, the extracellular vesicles shed into the blood protect their genetic cargo against differing environmental conditions” (3). The replicated results suggest that the biomarkers have potential for further research and clinical use, though it may take time for a commercial test to become available to physicians worldwide.

Outside the diagnostic world, the FDA has approved the first drug for people living with ALS, though its phase III trial is still ongoing (5). Remember the ALS Ice Bucket Challenge back in 2014? The ALS Association invested US$2.2 million of funds raised by the challenge into the AMX0035 trial – which just goes to show the power of social media!