Feature: Cough medicine shows promise in treating Parkinson’s disease

neuronBy Emily Leighton, MA'13

An over-the-counter cough medicine may be the key to slowing the progression of Parkinson’s disease.

Called Ambroxol, the drug is commonly used to break up phlegm, but early studies have shown it can also prevent the build-up of misfolded clumps of protein in the brain, known as Lewy bodies – a hallmark of Parkinson’s and other types of dementia.

Robarts scientist Dr. Stephen Pasternak is leading a phase 2 clinical trial to further study Ambroxol’s potential as a disease-modifying drug.

“Current treatments for Parkinson’s target the symptoms of the disease, such as movement, but don’t change the long-term progression of pathology in the brain,” he explained. “We hope Ambroxol will be a disease-changing drug.”

Ambroxol binds to and stabilizes an enzyme in the brain called glucocerebrosidase. When this enzyme is unable to do its job correctly, the protein alpha-synuclein accumulates, forming the Lewy bodies that impact dopamine production.

By stabilizing the enzyme, the drug may be able to reduce the formation of Lewy bodies at their source, slowing or even stopping the progression of the disease.

A neurologist specializing in memory and thinking, Dr. Pasternak co-leads the Cognitive Neurology and Alzheimer Research Centre based at St. Joseph’s Health Care London’s Parkwood Institute and is particularly interested in the cognitive symptoms associated with Parkinson’s disease.

After 10 years of living with Parkinson's disease, about half of patients will develop cognitive impairment. “One of the biggest unmet needs is to look at how we can stop cognition from getting worse,” said Dr. Pasternak.

Patients participating in the clinical trial have been diagnosed with Parkinson’s and have also developed mild cognitive impairment. They are randomized to receive either Ambroxol or a placebo and followed for one year, undergoing cognitive and motor testing. To date, 50 patients have been enrolled, and the research team is hoping to enrol at least 58 patients before the trial closes later this year.

After the one-year trial period, there is also a six-month open label period where all patients are invited to receive Ambroxol if they would like it.

Ambroxol is not currently approved for use in Canada or the U.S., so researchers received special approval from Health Canada to use it in the trial, following European dosing guidelines. The research is funded by the Weston Brain Institute.

Dr. Pasternak is optimistic the trial will lead to new ways to treat Parkinson’s and other types of dementia. “This is a trial people from all over the world are watching,” he said. “If this is successful, we could potentially start identifying people early on who are at high risk of getting these diseases and stop them from progressing.”

If you are interested in learning more about the clinical trial, please contact Kathy Borron by email at kathy.borron@sjhc.london.on.ca.