Impact of Oral Fast Release Amantadine on Movement Performance in Patients with Parkinson's Disease

GOCOVRI® (amantadine) extended-release capsules in Parkinson's disease

Amantadine is an old, antiviral compound, which moderately improves motor behavior in Parkinson's disease. Its current resurgence results from an innovative, delayed uptake and extended release amantadine hydrochloride capsule, given at bedtime once daily. It is the only approved compound for reduction of involuntary movements, so called dyskinesia, in fluctuating orally levodopa treated patients. It additionally ameliorates 'off'-intervals characterized by impaired motor behavior. These beneficial effects result from higher and more continuous brain delivery of amantadine. Future clinical research is warranted on preventive effects of this amantadine capsule combined with enzyme blockers of central monoamine oxidase B and peripheral catechol-O-methyltransferase on motor complications in orally levodopa treated patients, as all these pharmacological principles support the concept of continuous dopamine substitution.

Recent Clinical Advances in Pharmacotherapy for Levodopa-Induced Dyskinesia

Onset of involuntary movement patterns of the face, body and limbs are known as dyskinesia. They mostly appear in association with long-term levodopa (L-dopa) therapy in patients with Parkinson's disease. Consequences include patient distress, caregiver embarrassment and reduced quality of life. A severe intensity of this motor complication may result in troublesome disability; however, patients typically prefer motor behaviour with slight, non-troublesome dyskinesia to 'OFF' states. Pharmacotherapy of dyskinesia is complex. Continuous nigrostriatal postsynaptic dopaminergic receptor stimulation may delay onset of L-dopa-associated dyskinesia, while non-physiological, 'pulsatile' receptor stimulation facilitates appearance of dyskinesia. In the past, there have been many clinical trial failures with compounds that were effective in animal models of dyskinesia. Only the N-methyl-D-aspartate antagonist amantadine has shown moderate antidyskinetic effects in small well-designed clinical studies. Amantadine is an old antiviral compound, which moderately improves impaired motor behaviour. Recently, there has been a resurgence of its use due to the US Food and Drug Administration approval of an extended-release (ER) amantadine formulation for treatment of L-dopa-induced dyskinesia. This pharmacokinetic innovation improved dyskinesia and 'OFF' states in pivotal trials, with a once-daily oral application in the evening. Amantadine ER provides higher and more continuous amantadine plasma bioavailability than conventional immediate-release formulations, which require administration up to three times daily.

Evaluating ADS5102 (amantadine) for the treatment of Parkinson's disease patients with dyskinesia

Introduction: Amantadine is an old, antiviral compound that moderately ameliorates impaired motor behaviour in Parkinson's disease. Its current resurgence results from the novel retarded release amantadine hydrochloride formulation, ADS5102, which has also received approval for the treatment of levodopa-related involuntary movements known as dyskinesia. Areas covered: This non-systematic, narrative drug evaluation discusses the value of ADS5102 for patients with Parkinson's disease. ADS5102 is orally applied once daily in the evening. This capsule provides higher and more continuous amantadine plasma concentrations than conventional amantadine immediate release formulations with their two to three times daily intake plan. Expert opinion: ADS5102 was superior to placebo in clinical trials. They aimed for the amelioration of motor complications, particularly at 'OFF' periods and with dyskinesia in fluctuating levodopa treated patients with Parkinson's disease. Side effects and tolerability were similar to the well-known effects of conventional amantadine formulations. ADS5102 simplifies treatment and improves compliance problems in the long run. The marketing of ADS5102 outside the US will be complex for return of research costs and investments required for its manufacturing. Indeed, worldwide institutional price regulation scenarios often only consider new therapeutic mode of actions as being innovative as opposed to old drugs with improved pharmacokinetic behaviour.

Safinamide: an add-on treatment for managing Parkinson's disease

Heterogeneous expression of neurotransmitter deficits results from onset and progression of Parkinson's disease. Intervals, characterized by reappearance of motor and associated certain nonmotor symptoms, determine the end of good tolerability and efficacy of oral levodopa therapy. These "OFF" states result from levodopa pharmacokinetics and disease progression-related deterioration of the central buffering capacity for fluctuations of dopamine levels. This review discusses safinamide as an add-on therapeutic agent in orally levodopa-treated patients with "OFF" phenomena. Safinamide provided beneficial effects on "OFF" symptoms in pivotal trials with doses of 50 or 100 mg once daily. Safinamide reversibly inhibits mono-amine oxidase B and declines abnormal glutamate release by modulation of potassium- and sodium ion channels. An ideal candidate for combination with safinamide is opicapone. This inhibitor of peripheral catechol-O-methyltransferase supports continuous brain delivery of levodopa and, thus, the continuous dopaminergic stimulation concept. Both compounds with their once-daily application and good tolerability may complement each other by reduction of necessary oral levodopa intakes and "OFF" times. Thus, a promising, future option will be combination of safinamide and opicapone in one formulation. It will reduce adherence issues and may complement levodopa treatment. It will probably cause less nausea and edema than a dopamine agonist/levodopa regimen.