My thanks go to NewsBot for pointing me to this:

Adamas Pharma says its new Parkinson’s drug isn’t just a more expensive, long-acting version of generic - MarketWatch

"Gocovri is a new formulation of amantadine, at a new price: between $10,000 and $30,000 a year."

'... Chief Executive Greg Went and Chief Medical Officer Rajiv Patni emphasized that there are other important differences. Gocovri is “not a convenience play” but rather a new chemical entity that is designed to be more effective, they said; moreover, the product represents 13 years and “well over” $100 million in investment.'

For sure there is a different release mechanism, but does anyone know how Gocovri differs chemically from amantadine?

John