Parkinson’s disease is a chronic, progressive and debilitating neurodegenerative condition resulting from a failure to produce adequate levels of the neurotransmitter dopamine in the motor regions of the central nervous system (CNS), which are responsible for controlling movement. Common symptoms include tremors in the hands, arms, legs and jaw, rigidity in the limbs and trunk, slowness of movement (bradykinesia), involuntary movements (dyskinesias) and impaired balance and co-ordination. In addition to these motor symptoms, there are significant non-motor symptoms commonly associated with the disease, including mood disorders and cognitive disorders. There is growing acknowledgement of the negative impact of these non-motor symptoms, and the high unmet medical need in Parkinson’s disease patients, resulting from both the motor and non-motor symptoms.
According to the Parkinson’s Disease Foundation, over 60,000 new cases of Parkinson’s disease are diagnosed each year in the United States and this number is expected to increase as the population ages. Current therapy focuses on the use of ‘dopaminergic agents’, including L-dopa and the dopamine agonists, and dopamine extenders such as the MAO-B and COMT inhibitors. The widely used L-dopa is converted to dopamine in the brain and compensates for the loss of endogenous dopamine production. However, prolonged therapy with L-dopa is linked to side effects such as nausea and increased involuntary movements (dyskinesia). Dopamine agonists are associated with nausea, day time sleepiness (somnolence) and compulsive disorders. Although existing agents are quite effective in the early stages of the disease, in later stages patients often suffer unpredictable periods of ‘on-off’ syndrome, when the drugs fail to treat the disease symptoms.
There have been no new therapeutic mechanisms introduced for the treatment of Parkinson’s disease over the past 15 years. As a result, the symptomatic treatment of the motor and non-motor symptoms represents an increasing unmet medical need.
USEFUL LINKS:
European Parkinson's Disease Association (EU)