Memantine might lessen deterioration and improve behavioural symptoms in patients with a neurodegenerative disease known as dementia with Lewy bodies (DLB)*, and has the potential to become a treatment option for these patients, according to the largest study of memantine in patients with Lewy-body-related dementias, published in an Article Online First and in the October edition of The Lancet Neurology (www.thelancet.com).
The drug memantine blocks the excessive actions of the brain chemical glutamate without affecting the activity of glutamate receptors that are essential for normal brain function. Memantine has shown beneficial effects in Alzheimer's disease and could be a potential treatment for other brain disorders that may involve an excess of glutamate stimulation, such as Lewy-body-related dementias (Parkinson's disease dementia [PDD] and DLB).
In this study, an international team led by Murat Emre from Istanbul University in Turkey investigated the safety and efficacy of memantine for the treatment of mild to moderate PDD and DLB. Over 6 months, 199 patients (121 PDD and 78 DLB) from 30 specialist centres across Europe were randomly assigned to receive memantine (20 mg) or placebo once a day. Functional, behavioural, cognitive, and global outcome measures were recorded at the start of the study and at the end of weeks 4, 12, 16, and 24. Additionally, caregivers were interviewed to assess the strain on carers during the study.
After 24 weeks, more patients treated with memantine showed improvement in clinical status, as observed by clinicians, compared with the placebo group.
Overall, more DLB patients who were taking memantine had a favourable response, and this group showed a significantly greater improvement in global clinical status and behavioural symptoms than those taking placebo. However, no significant differences were found between the two treatments in patients with PDD.
Additionally, there were no significant differences in treatment outcomes associated with activities of daily living, motor symptoms, or caregiver burden.
Memantine was generally well tolerated and side-effects were mild and similar between the two treatment groups. The most common serious adverse events were stroke (three in the memantine group), falls (two in the memantine group; one in the placebo group), and worsening of dementia (two in the memantine group).
Patients with DLB seemed to benefit more from memantine than those with PDD and the authors suggest that this might be because DLB has more pathological similarities to Alzheimer's disease than does PDD.
They conclude: "On the basis of the results of this study, memantine might be a treatment option in patients with mild to moderate DLB."
In a Comment, Laura Marsh from Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Texas, USA, says that the study highlights the complexity of the clinical management of patients with Lewy-body-related dementias. She points out that memantine is a symptomatic treatment and not a cure and emphasises the urgent need for pharmacological treatments that address cognitive impairment in Parkinson's disease and related disorders before the development of frank dementia.
Professor Murat Emre, Istanbul University, Istanbul, Turkey. T) +90 212533 8575 (please call between 09:00 and 13:00 Istanbul time) E) muratemre@superonline.com
Dr Laura Marsh, Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Texas, USA. T) +1 713 794 8907 E) laura.marsh2@va.gov
For full Article and Comment see: http://press.thelancet.com/tlnmem.pdf
Notes to Editors:
*Dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD) are neurodegenerative diseases associated with Lewy bodies—abnormal deposits of proteins that develop inside the brain's nerve cells. Together Lewy-body-related dementias are the second most common neurodegenerative cause of dementia after Alzheimer's disease.
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Journal
The Lancet Neurology