"Treatment with naltrexone leads to a sustained reduction in heavy drinking over an extended treatment period," said principal investigator David Gastfriend, MD, Vice President of Medical Affairs, Alkermes, which manufactures Vivitrex, and Professor of Psychiatry, Harvard Medical School, Boston, Massachusetts, United States.

The findings are from a 1-year open-label extension of a previous 24-week, multicenter, double-blind, placebo-controlled study that enrolled 624 patients with confirmed alcohol dependence. The investigators defined heavy drinking as five or more alcoholic drinks per day for men and four or more such drinks per day for women.

In the earlier study, subjects had received 6 monthly injections of a depot formulation of naltrexone at either 380 mg or 190 mg, or placebo. All patients also received psychosocial support that was consistent with the BRENDA approach, a manualized counseling strategy for alcohol dependence developed at University of Pennsylvania that consists of the following system:

· Conducting a thorough Biopsychosocial evaluation
· Giving people a Report of how their drinking is causing problems
· Using Empathy to help people feel understood by the therapist
· Understanding the person's Need for wanting to recover
· Offering Direct advice
· Assessing the response to direct advice

Among the 380 patients (61%) who completed the study, 332 (87%) enrolled in the 1-year open-label extension. All patients were given 380 mg of naltrexone per month.

Of particular interest was the group who had been on 380 mg per month of naltrexone in both phases of the study and the group switched from placebo. Those who continued at this dose during both phases had a median reduction from 2.6 days of heavy drinking per month in the first study to 1.6 in the extension, not a significant difference.

Among patients who were switched from placebo, the median number of heavy drinking days decreased from 5.2 days per month in the main trial to 1.8 days per month in the extension (P < .01).

Throughout the 18 months in both studies, patients tolerated treatment well, Dr. Gastfriend said.

He noted that, during the extension study, the most common adverse events consisted of headache, nasopharyngitis, and upper respiratory tract infections.

The study was funded by Alkermes, the manufacturers of Vivitrex.


[Presentation title: Durability of effect of long-acting injectable naltrexone. Abstract NR280]

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