Avanir Pharmaceuticals has reported safety and efficacy results from its Phase II clinical trial of its investigational drug AVP-923 in patients with Alzheimer's disease.
AVP-923 is a combination of dextromethorphan (DM) hydrobromide (an uncompetitive NMDA receptor antagonist and sigma-1 receptor agonist) and low dose quinidine (Q) sulfate (a CYP2D6 enzyme inhibitor). It has not been approved by the US Food and Drug Administration (FDA).
Avanir chief medical officer Dr Joao Siffert said: "With no FDA approved drugs for the treatment of agitation in Alzheimer's disease, we believe these results represent a breakthrough for patients.
"These study results represent the second neuropsychiatric disorder where AVP-923 has shown benefit and lends support for further advancement of our research programmes into related disorders."
In the 10-week Phase II multicentre, double-blind, placebo-controlled studies, around 220 Alzheimer's patients in the US were initially randomised 3:4 to receive either AVP-923 (dose escalated from DM 20mg/ Q 10mg to DM 30mg/ Q 10mg) or placebo.
Patients who initially received placebo were stratified at the end of week five according to their response to treatment and subsequently re-randomised 1:1 to receive either AVP-923 or placebo for an additional five weeks of treatment.
For the remainder of the study, patients who initially received AVP-923 continued to receive AVP-923 DM 30mg/ Q 10mg.
The primary objective of this Phase II study was to evaluate the safety, tolerability, and efficacy of AVP-923 for the treatment of agitation in Alzheimer's patients.
The main efficacy measure is the agitation/aggression subscale of the Neuropsychiatric Inventory (NPI).
Cleveland Clinic Lou Ruvo Center for Brain Health and chair of the study steering committee, director Dr Jeffrey Cummings said: "This is an exciting advancement in Alzheimer's disease research.
"Dementia-related neuropsychiatric symptoms such as agitation are extremely distressing to patients and their families."
Avanir plans to present the data from this Phase II study at the American Neurological Association Meeting in October.
Based on these results, the company plans to request a meeting with both the FDA and the European Medicines Agency (EMA) to discuss initiation of pivotal development programmes.