Alkermes, Inc. (NASDAQ: ALKS) today 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. The six-month phase 3 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). Based on the positive results of this phase 3 study, Alkermes plans to file a supplemental New Drug Application (sNDA) with the U.S. Food and Drug Administration (FDA) in the first half of calendar 2010. 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.
In addition to meeting the primary efficacy endpoint, the six-month phase 3 study met all secondary efficacy endpoints. Data from the intent-to-treat (ITT) analysis show that the median patient taking XR-NTX had 90% opioid-free urine screens during the evaluation phase of the study and patients treated with XR-NTX demonstrated a significant reduction in opioid craving compared to placebo as measured by a visual analog scale. XR-NTX was generally well tolerated in the study and no patients on XR-NTX discontinued the study due to adverse events. The most common adverse events experienced by patients receiving XR-NTX during the study were nasopharyngitis and insomnia.