SIGNAL trial: pepinemab does not affect Huntington disease's symptoms
The SIGNAL trial began in 2015 in 20 centers across the United States, involving 301 patients with Huntington's disease in the early stages or not yet symptomatic .
The study was designed to test whether a drug called pepinemab (also known as VX15) produced by Vaccinex, was safe for people with HD, and whether it could slow the effects of HD, like changes to the brain, and difficulties with thinking, movements, and behavior.
Study participants visited study sites every month for a year to receive an intravenous (IV) drip. Half of participants received pepinemab, and half got a placebo, a saline solution with no drug (essentially some extra fluids). Many visits included tests and procedures, like MRI imaging, learning and memory activities, physical exams, and blood draws. SIGNAL was a double-blind clinical trial, that is to say that was o prevent any bias during these visits, neither the participants nor the doctors knew who was getting pepinemab and who was getting placebo.
After the first year, participants continued to come in for visits for an additional 6 months or up to two years, to monitor their health, safety, and abilities during and after the trial.
Key results from the trial were announced recently, and although pepinemab was deemed safe and tolerable, the study has not achieved its 'primary endpoints’. That’s because the participants who received the drug did not perform better than those who received the placebo, on either the cognitive tests or the doctor’s assessment
Although slight improvements were registered in some tasks used to test cognitive activities, they did not reach “statistical significance,” which means that there was no mathematical difference between the placebo and drug groups .
This doesn’t mean that the study was useless. A good clinical trial mainly aims to provide the research community more information about a drug and the disease. The SIGNAL trial, regardless to its success has opened new paths on only for Huntington’s disease- pepinemab could still benefit a different group of people with HD- but also for other diseases which cause cognitive impairment, like Alzheimer’s. "Although the results do not confirm the achievement of the primary endpoints, the positive aspect is that we now know that an experimental drug could be functional in advanced stages of the disease. Especially in contrasting the decline of cognitive functions, an aspect notoriously difficult to treat" this is Ferdinando Squitieri's statement.
Participating to clinical trials is never useless because, in any case, it allows us to fix the target towards the most appropriate and effective path to follow.