Avanir Pharmaceuticals, a bio-pharmaceutical company, announced the completion of patient enrollment in the company's phase II, placebo controlled study testing AVP-923 for the treatment of agitation in Alzheimer's disease patients. Top-line results from this study are expected late September/early October.

"Final completion of enrollment in this study is an important milestone for Avanir as we explore the therapeutic utility of AVP-923, and later AVP-786 for the management of neuropsychiatric manifestations of neurological disease, including agitation," said Joao Siffert, MD, chief medical officer at Avanir. "We are looking forward to the results from this study to potentially help guide the phase III development of AVP-786 for the treatment of agitation in patients with Alzheimer's disease. AVP-786 is our next generation investigational product containing deuterium modified dextromethorphan and ultra-low dose quinidine."

The objectives of this proof of concept study are to evaluate the safety, tolerability, and efficacy of AVP-923 for the treatment of agitation in Alzheimer's patients. The trial is a multicenter, randomised, double-blind, placebo-controlled study that enrolled 220 Alzheimer's patients in the United States. Eligible patients were randomized to receive either AVP-923 (dose escalated from DM 20mg/ Q 10mg to DM 30mg/ Q 10mg) or placebo for 10 weeks. The main efficacy measure is the agitation/aggression subscale of the Neuropsychiatric Inventory or NPI. Secondary outcome measures include global assessments of disease severity, other neuropsychiatric symptoms, cognition, activities of daily living, quality of life and caregiver strain. Standard safety assessments will also be conducted.

AVP-923 is a combination of two well-characterized compounds, the active CNS ingredient dextromethorphan hydrobromide (an uncompetitive NMDA receptor antagonist, sigma-1 receptor agonist and inhibitor of the serotonin transporter (SERT) and norepinephrine (NET) transporter) 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, levodopa-induced dyskinesia in Parkinson's disease, and multiple investigator initiated studies. AVP-923 is an investigational drug not approved by the FDA.

AVP-786 is a novel investigational drug product consisting of a combination of deuterium modified dextromethorphan and ultra-low dose quinidine, used as a metabolic inhibitor. Incorporation of deuterium into specific positions of the dextromethorphan molecule strengthens the chemical bonds and reduces susceptibility to enzyme cleavage and first pass metabolism, but without altering its pharmacology. AVP-786 is an investigational drug not approved by the FDA.