** Shares of drugmaker Amneal Pharmaceuticals AMRX.O rise 2.3% to $13.83 premarket

** AMRX says interim data from a late-stage study showed its Parkinson's treatment, Crexont, improved symptom control in patients switching from other therapies

** After six weeks, study of 214 patients showed Crexont helped people spend more time with well-controlled symptoms and less time with symptoms returning, regardless of previous treatment

** Patients switching from standard treatment gained over three extra hours a day of well-controlled symptoms - AMRX

** Study also showed improvements in motor function

** Side effects included dizziness, falls, nausea and dyskinesia, co says

** Adds patients in the ongoing study will be followed for 12 more months, with additional results expected later this year

** Crexont is an extended-release formulation of carbidopa/levodopa, a standard Parkinson's treatment

** U.S. FDA approved Crexont in August 2024 for Parkinson's disease

** As of last close, stock up about 7.3% YTD