Treatment with the dopamine precursor levodopa, optimized with other oral drugs (e.g., dopamine agonists), effectively controls motor symptoms in Parkinson's disease (PD). Unfortunately, such combinations become ineffective as the disease progresses, and motor complications emerge. These include motor fluctuations known as "on" and "off" states, in which a patient either retains the ability to respond to levodopa, and thus move, or is unresponsive to the drug and immobile. In addition, most patients with advancing PD experience dyskinesias, the involuntary movements that occur during peak levodopa concentrations. Unsurprisingly, the emergence of motor complications can be devastating; as patients lose the ability to perform routine daily tasks, they are at risk of severe mood disorders and are more and more dependent on caregivers, resulting in higher treatment costs.
Because of the severity of the disease and the unmet medical need, competition to develop more effective treatments for motor...
