What is the drug thought to do in the body?
Pridopidine is a drug that binds to a receptor on the surface of cells in the brain and spinal cord. Receptors are proteins on the outside of cells that get activated by specific signals outside of the cell. Once activated, they cause a chain reaction of events within the cell.
Pridopidine binds to the Sigma-1 receptor, which is a gene thought to be linked to MND. The receptor is present in high amounts in the brainstem and spinal cord, which are areas of the body important for speech, swallowing and limb function. When activated, the Sigma-1 receptor promotes protective responses by changing the activity of cellular pathways that are known to be changed in MND. This includes promoting increased clearance of toxic protein clumps, increased energy production and decreased cellular stress and inflammation. Pre-clinical data has shown that activation of Sigma-receptor 1 can increase neuronal survival and function, as well as increase muscle function, in models of MND.
Phase 3 Trial - PREVAiLS
Current status: Recruiting
Primary objective: To investigate whether Pridopidine is safe and effective for people with MND.
The phase 3 trial will test Pridopidine, to see if the drug has an effect on the ALSFRS-R score and survival. They will also measure vital capacity (the amount of air which can be expelled from the lungs after taking a deep breath). People who take part in the trial will be randomly allocated to receive either Pridopidine or a placebo (dummy drug) which will be given as tablets. The trial aims to recruit 500 people and will last 48 weeks. After the trial is completed, all participants will have the opportunity to receive Pridopidine in an open label extension. You can find out more about the trial here.
This trial is recruiting in the USA.
Clinical Trials
Phase 2/3 - Healey Platform Trial
Pridopidine was tested in the HEALEY ALS Platform trial. The trial arm tested a single dose of the drug, which was taken by mouth, twice a day, for 6 months. Results from the study showed that it did not meet its primary or secondary endpoints. This meant that participants randomised to Pridopidine did not have a statistically significant slowing of disease progression as measured by ALSFRS-R over 24 weeks, compared to participants taking the placebo. They also showed no significant improvement to muscle strength or respiratory function. However, the results showed that Pridopidine was found to have a potential greater benefit for those who were early in the course of the disease (within 18 months of symptom onset) with a definite or probable ALS diagnosis.
The mechanism of action of the drug suggests it may have benefits for people living with MND with swallowing and speech-related symptoms, which are often referred to as bulbar symptoms. The trial found improvements in speaking rate and articulation rate for those who took Pridopidine compared to those who took placebo. The positive results on speech and bulbar function showed that more trials are needed to explore how the drug might be beneficial for people with MND. You can read more about the results in a press release.
Latest News
2026
March 2026- Prilenia and Ferrer Announce that the first participant is enrolled in the “PREVAiLS” Phase 3 Study.
Resources
Last updated: 01/04/2026