JUL 20, 2016

A Cancer Drug For Parkinson's? Not So Fast...

WRITTEN BY: Brenda Kelley Kim
Parkinson’s disease (PD) can be devastating, to those who have it, and to those that care for them. The progress of the disease is slow and sometimes early symptoms are not picked up on right away. Problems with remembering words or becoming more clumsy with walking and carrying things are often just chalked up to old age. Sadly, once the disease takes hold, patients lose a great deal of their abilities. Tremors can impact working, daily activities and even eating. Speech problems make it hard to be understood. Eventually, patients lose the ability to walk or talk at all.
 
There is no definitive test for PD, so patients often have to suffer through multiple tests and doctors visits over long periods of time to finally rule everything else out and arrive at a diagnosis of PD. Naturally, this causes patients and their families a great deal of stress so whenever there is a new treatment in the news, there is a huge influx of patients calling research hospitals, the CDC and their doctors to find out how to access a new treatment.
 
That was the case recently when a very small study done at Georgetown University Medical Center showed promising results for PD patients when they used a cancer drug nilotinib (brand name Tasigna). The drug is a type of cancer agent classified as a tyrosine kinase inhibitor. Small amounts of the drug do reach the brain and it’s believed that once there it helps cells shed toxic proteins. PD is believed to be related to the death of cells in the brain as a result of some toxin, but no research has yet shown specifically what the toxin is and how it works. What is known is that the cells that die in Parkinson’s patients are ones that produce dopamine, which is involved in controlling movement. Nilotinib boosts dopamine levels.
 
When the news of the study was made public, patients were clamoring for the drug since it is already on the market for the treatment of leukemia but there were several issues with the study and caution is being advised by the study research team as well as the Parkinson’s Disease Foundation VP for Scientific Affairs, James Beck.
 
Beck pointed out that while the drug may show promise (there was a mouse model study on PD and nilotinib in 2013) the study at Georgetown was not conclusive. The major issue was the size of the study. There were only 12 participants in the study. While 11 of the patients did show improvement in motor and memory skills, there is no evidence that a larger study would replicate those results. Also, all 12 patients were taking nilotinib and knew they were. There was no control group and the study was not blind.  Finally, all of the patients in the study were in the advanced stages of the disease and all had at least a moderate degree of dementia and memory loss.
 
The senior researcher on the study Dr. Charbel Moussa, an assistant professor of neurology at Georgetown told UPI, "We have to be very cautious about the safety profile of this drug in Parkinson's patients. We also need to clarify the symptom areas that it may benefit, [and] how and when should this drug be used." Check out the video below for more information on the study.

Sources: UPI, Parkinson’s Disease Foundation, Saint Louis Post Dispatch