As rare, neurodegenerative diseases go, amyotrophic lateral sclerosis—or ALS—“enjoys” an unusually high profile.
This is due in no small part to both the ice bucket challenge that was everywhere a couple of years ago (and which yielded real research benefits) and physicist Stephen Hawking providing a highly visible public face to ALS. But for all this visibility, new treatments have been hard to come by.
That may be changing, though. The FDA recently approved the first new ALS treatment in 22 years, and the French biotech AB Science has announced the results of a clinical trial showing their anti-inflammatory drug masitinib could reduce ALS symptoms by as much as 27%. Obviously, that’s fantastic news. But not all scientists are convinced the masitinib results tell the full story.
Here’s what we know: masitinib is a protein inhibitor that targets a type of protein called tyrosine kinases. Targeting these proteins can help reduce inflammation in immune system cells that play a role in ALS.
Reducing inflammation helps protect muscles and nerves from damage caused by ALS—there’s even data to suggest it crosses the blood-brain barrier to provide even greater protection. That in itself is reason for optimism, and some ALS experts believe it’s a step in the right direction.
But others caution that there are some inconsistencies in the data, and that the positive results were obtained by separating out the patients who were losing muscle and nerve function at a pace faster than others in the trial. While experts point out that this is not necessarily the wrong way to design the study—quite the opposite, actually—it does point to the highly variable disease progression of individuals with ALS.
In some cases, like Stephen Hawking, progression is a long, gradual process that unfolds over decades. In others, progression is extremely rapid and measured in months, not years. So when factoring in the rapidly progressing patients, the trial data averages out to something that is somewhat less impressive.
That data point, paired with regulators in France auditing some of AB Science’s earlier studies, suggests that more work needs to be done. That by no means invalidates the findings for masitinib: it just means more studies are needed to assess a broader range of patients with different rates of disease progression to confirm just how much ALS progression is slowed for each group. And there is every reason to believe those studies can and will happen—as well as additional studies that are already in the works that combine masitinib and the previously approved ALS drug riluzole.