Phase 3 Clinical Trial Shows Sustained-Release Amantadine Improves Levodopa-Induced Dyskinesia in Individuals with Parkinson Disease

Results from a phase 3 study showed a sustained improvement in levodopa-induced dyskinesia (LID) in individuals with Parkinson disease (PD) treated with amantadine extended-release capsules (GOCOVRI; Adamas Pharmaceuticals, Inc., Emeryville, CA). 

The medication provides an initial lag and a slow rise in amantadine concentration during the night, resulting in a high concentration in the morning and throughout the day. 

The therapy is indicated for dyskinesia in individuals with PD who receive levodopa-based therapy, with or without concomitant dopaminergic medications. The drug is clinically proven to reduce both dyskinesia and OFF.

The 2 year open-label trial (NCT02136914) enrolled 223 participants. Results showed that the treatment effect of amantadine on motor complications (dyskinesia and OFF), as measured by the Movement Disorder Society-Unified Parkinson Disease Rating Scale (MDS-UPDRS) Part IV, was maintained for at least 2 years. 

This effect was seen in all subgroups, including those who continued treatment from prior double-blind trials, from placebo, or amantadine immediate release (IR), as well as a subgroup of participants with dyskinesia who received deep brain stimulation (DBS) treatment.

“As the longest-running amantadine study to date, this open-label trial suggests GOCOVRI may provide sustained improvement in both dyskinesia and OFF to a wide cohort of patients with PD living with motor complications,” said Caroline Tanner, MD, professor, department of neurology, University of California, San Francisco. “These results expand not only our knowledge of GOCOVRI efficacy but also of its long-term safety in these patients.”

“These newly published results suggest that GOCOVRI may reduce dyskinesia and OFF as far out as 100 weeks, providing sustained benefits to patients with levodopa-induced dyskinesia,” said Jean Hubble, MD, vice president of medical affairs, Adamas. “Given the chronic nature of PD, both patients and physicians seek treatments that are effective long-term.”