Today, a team of researchers supported by The Michael J. Fox Foundation (MJFF) is announcing encouraging clinical results for a drug to treat dyskinesia in people with Parkinson’s disease (PD).

The trial focused on Eltoprazine, a drug which has shown promising pre-clinical results targeting neurons in the brain that produce a neurotransmitter called serotonin. Researchers think that serotonin neurons may play a role in causing dyskinesia.

Here’s the basic idea behind this novel hypothesis: Levodopa, the gold standard PD drug, is designed to get dopamine neurons to make more dopamine, in order to treat symptoms caused by the loss of dopamine taking place in PD. But levodopa may also cause serotonin neurons to make dopamine, something they’re not designed to do, and this might cause dyskinesia. Researchers hope Eltoprazine could prevent this process from taking place.

According to MJFF’s Jamie Eberling, PhD, today’s announcement suggests Eltoprazine may do just this. Researchers found that one particular dose of the drug made a “real difference” in limiting dyskinesia in those who participated in the study. But while the study results were positive, she cautions, they were culled from a small early stage study meant to find out if the drug would provide any initial positive data and didn’t make participants’ PD symptoms worse (both of these turned out to be true).

The next step will be to design a larger scale study to find out if the drug could be efficacious in treating dyskinesia. Eltoprazine is also currently undergoing clinical testing to treat cognitive impairment, schizophrenia, and attention deficit hyperactivity disorder (ADHD).