Alkermes Inc. announced positive preliminary results from a Phase 3 clinical trial of naltrexone for extended-release injectable suspension (XR-NTX) for the treatment of opioid dependence.  This six month, randomized, multi-center study met its primary efficacy endpoint and data showed that patients treated once-monthly with XR-NTX demonstrated statistically significant higher rates of clean (opioid-free) urine screens, compared to patients treated with placebo, as measured by the cumulative distribution of clean urine screens (p<0.0002). The primary efficacy endpoint was the response profile based on the rate of urine drug screens that were free of opioids during the last 20 weeks of the 24-week double-blind treatment period, as measured by the cumulative distribution of clean urine screens. The secondary efficacy endpoints in the study were the study retention rate, craving scores, self-reported opioid use and the incidence of physiologic opioid dependence.

XR-NTX, marketed by Alkermes as Vivitrol, is an opioid antagonist administered once-monthly by intramuscular injection and is approved in the U.S. for the treatment of alcohol dependence. If approved by the FDA for the treatment of opioid dependence, XR-NTX has the potential to be the first and only non-narcotic, non-addictive drug agent available in a once-monthly formulation.

For more information call (617) 494-0171or visit www.alkermes.com.