ALISO VIEJO, Calif., Oct. 22, 2013 /PRNewswire/ -- Avanir Pharmaceuticals, Inc. (NASDAQ: AVNR) today announced the enrollment of the first patient in study AVR-133. The study is a proof of concept, Phase II clinical trial investigating the use of AVP-923 for the treatment of levodopa induced dyskinesia (LID) in patients with Parkinson's disease (PD). (Logo: http://photos.prnewswire.com/prnh/20130207/LA55901LOGO) "This is an important study of a compound with multifaceted pharmacology for the management of levodopa induced dyskinesia in Parkinson's disease," said Anthony E. Lang, MD, Professor and Director of the Division of Neurology and Chair for Parkinson's Disease Research at the University of Toronto. "Despite advances in PD therapeutics, many patients still suffer with poorly controlled dyskinesias, especially as they require higher doses of medications to increase dopamine levels. Dyskinesias can not only be disabling but may also limit the dose of effective medications that treat core symptoms of PD." Top line data for this study is expected in the second half of calendar 2014. About the Study This proof-of-concept, double blind, randomized, crossover study will compare AVP-923 (45 mg of dextromethorphan / 10 mg of quinidine) with placebo for treatment of LID. The study will enroll approximately 16 PD patients across three study centers in the US and Canada. Study participants will receive, in a random order, a 2-week treatment with AVP-923 and a 2-week placebo treatment, separated by a 2-week break. At the end of each 2-week treatment period, patients will receive a 2-hour levodopa infusion to test the drug effect on dyskinesia. Patients will be carefully monitored throughout the 6-week study for side effects, Parkinson's symptoms and general health status. The results of this study will help inform future development of AVP-923 for LID. About AVP-923 AVP-923 is a combination of two well-characterized compounds, the active CNS ingredient dextromethorphan hydrobromide (an uncompetitive NMDA receptor antagonist and sigma-1 receptor agonist) plus low-dose quinidine sulfate (a CYP2D6 enzyme inhibitor), which serves to increase the bioavailability of dextromethorphan. AVP-923 is being studied in several ongoing company sponsored Phase II clinical trials including agitation in Alzheimer's disease and neuropathic pain in Multiple Sclerosis. AVP-923 can interact with other medications and cause serious side effects and should not be used in patients taking certain drugs and in patients with specific cardiovascular risk factors. These are not all the risks from use of AVP-923. AVP-923 is an investigational drug and is not approved for the treatment of levodopa induced dyskinesia in patients with Parkinson's disease.