Parkinson's disease is a
neurodegenerative disorder characterized by the degenerative loss of dopaminergic neurons in the substantia nigra.
Dopamine deficiency is thought to disrupt motor control of the basal ganglia and cause characteristic motor symptoms in
Parkinson's disease such as
bradykinesia, akinesia, and
tremor. Therefore,
dopamine replacement
therapy is widely used in the clinical setting.
Safinamide is a novel, selective, and
reversible inhibitor of monoamine oxidase B expected to increase
dopamine levels in the brain and improve the symptoms of
Parkinson's disease. In addition,
safinamide shows non-dopaminergic actions such as
sodium channel blockade and inhibition of
glutamate release. Preclinical studies have demonstrated that
safinamide ameliorates "wearing off" symptoms after administration in rat and monkey models with selectively destroyed dopaminergic neurons. In the monkeys,
safinamide concurrently inhibited
levodopa-induced
dyskinesia. These findings suggest that
safinamide not only increases the
dopaminergic effect of
levodopa, but also reduces
levodopa-induced adverse events via its non-
dopaminergic effects. In clinical trials of patients with
Parkinson's disease with the "wearing off" phenomenon,
safinamide has been found to prolong the "on time" and improve motor function as assessed by Unified Parkinson's Disease Rating Scale Part III. In Japan,
safinamide was approved in September 2019 as a
levodopa combination drug for
Parkinson's disease with "wearing off" phenomenon.
Safinamide is therefore expected to be a new treatment option for patients with
Parkinson's disease.