Avanir Pharmaceuticals Announces Results for Phase II PRIME Study

ALISO VIEJO, Calif., Dec. 10, 2013 /PRNewswire/ — Avanir Pharmaceuticals, Inc.  today announced that PRIME, its phase II clinical trial of the investigational drug AVP-923 (dextromethorphan / quinidine) for the treatment of central neuropathic pain in patients with multiple sclerosis did not meet the primary efficacy endpoint.

In the PRIME study, AVP-923 treated patients experienced levels of pain reduction commensurate with those observed in similar studies and the improvement in pain scores from baseline reached statistical significance; however, there was no difference between the treatment arms and placebo.  Avanir believes that a higher than expected placebo response negatively impacted the study results.  AVP-923 was generally safe and well tolerated.

Avanir plans to review the detailed data from the PRIME study in conjunction with previously generated data in diabetic peripheral neuropathic pain to determine next steps for the development of AVP-923 in neuropathic pain.

About the PRIME StudyThe objectives of the PRIME (Pain Research In Multiple sclErosis) study were to evaluate the safety, tolerability, and efficacy of AVP-923 for the treatment of central neuropathic pain in patients with multiple sclerosis. The trial was a multicenter, randomized, double-blind, placebo-controlled, 4-arm parallel group study that enrolled 209 patients. Eligible patients received one of three dose levels of AVP-923 containing either 45mg DM/10 mg Q, 30mg DM/10mg Q, 20mg DM/10mg Q or placebo, daily for 12 weeks. The primary efficacy endpoint was measured based on the Numeric Pain Rating Scale (PRS) as recorded in patient diaries. Primary analysis of this endpoint correlated pain scores with dextromethorphan plasma concentrations. Secondary analysis correlated pain scores with AVP-923 dose and also compared pain scores for those treated with placebo versus drug in each dose group.

About AVP-923AVP-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, levodopa-induced dyskinesia in Parkinson’s disease and several investigator initiated studies. AVP-923 can interact with other medications and should not be used in patients taking certain drugs. AVP-923 can cause serious side effects and should not be used in patients with specific cardiovascular risk factors. These are not all the risks from use of AVP-923. AVP-923 is an investigational drug not approved by the FDA.

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