A phase II clinical trial of the epilepsy drug, zonisamide, has shown promising results for people with dementia with Lewy bodies, reducing Parkinson’s symptoms when used alongside standard levodopa therapy. The findings from Japanese researchers were published today in the scientific journal, Neurology.
Dementia with Lewy bodies and Parkinson’s disease are caused by very similar disease processes and therefore can have a range of overlapping symptoms. Although dementia with Lewy bodies predominantly affects memory and thinking first, some people with the disease will go on to develop Parkinson’s symptoms, such as a slowdown in movement, increased muscle stiffness and frequent tremors. Levodopa therapy is currently used to treat these movement problem’s in people with Parkinson’s disease.
In this phase II clinical trial, scientists used an epilepsy drug called zonisamide alongside a participant’s current course of levodopa therapy. They set out to measure whether this could reduce the severity of Parkinson’s symptoms in people with dementia with Lewy bodies and whether the combination of drugs was safe.
The trial involved 158 people between the ages of 56 and 84 who were living with DLB. The volunteers were randomly split into one of three groups, receiving either a placebo or ‘dummy’ pill, or a 25 mg or 50 mg dose of zonisamide once a day for 12 weeks.
The volunteers underwent a Parkinson’s disease assessment at the end of the treatment, which showed that zonisamide reduced the severity of their symptoms. The drug did not have an effect on memory and thinking performance in the volunteers.
Some volunteers reported side effects including decreased appetite with more incidents reported when zonisamide was taken at the highest dose of 50 mg daily.
Dr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:
“Dementia can bring with it a range of distressing symptoms above and beyond memory and thinking problems, and effective management of these symptoms can make a huge impact on people’s lives. It’s encouraging that research is investigating an approach using a combination of treatments for dementia, but the findings here suggest important safety concerns need to be addressed before this approach can be taken forward to next stage of testing.
“We must continue to explore as many treatment options as possible to help people with dementia, including medicines currently used to treat other diseases as well as drugs that might have additional benefits when used in combination with existing treatments. With growing evidence of overlapping mechanisms between diseases that cause dementia and other health conditions, re-appropriating existing medicines for use in dementia may be a promising avenue in the search for new treatments.”
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