Cervene (Nalmefene) in acute ischemic stroke: Final results of a phase III efficacy study

Background and Purpose - The goals of the present study were to assess the efficacy and safety of nalmefene (Cervene) in patients with acute (≤6 hours) ischemic stroke and to investigate the safety of combined recombinant tissue plasminogen activator and nalmefene in a separate subset of patients. Nalmefene, an opioid antagonist with relative κ receptor selectivity, has shown neuroprotective effects in multiple experimental central nervous system injury and ischemic models. Results from an earlier phase II study in patients with acute ischemic stroke suggested that nalmefene was safe and tolerable and may be effective for patients <70 years old. Methods - This investigation was a phase III, placebo-controlled, double-blind, randomized study of a 24-hour infusion of nalmefene. Patients with acute ischemic stroke who had an onset of symptoms within 6 hours and a baseline score of ≥4 on the NIH Stroke Scale were randomized to receive either 60 mg nalmefene administered as a 10-mg bolus over 15 minutes and then a 50-mg infusion over 23.75 hours or placebo. The primary efficacy outcome was the proportion of patients achieving a score of ≥60 on the Barthel Index and a rating of 'moderate disability' or better on the Glasgow Outcome Scale at 12 weeks. Assessments were performed at baseline (predose), hours 12 and 24, days 2 and 7, and week 12. Results - A total of 368 patients were randomized at 42 centers, including 32 patients treated with recombinant tissue plasminogen activator and study drug. Nalmefene was well tolerated. Overall, there was no significant difference in 3-month functional outcome for nalmefene treatment compared with placebo on any of the planned analyses. A prospective secondary analysis also failed to find a treatment effect in patients <70 years old. Conclusions - Although nalmefene appears to be safe and well tolerated, this study failed to find any treatment benefit in stroke patients treated within 6 hours.