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Yale study shows lofexidine is effective in preventing opiate addiction relapse

BAL HARBOUR, FLA., June 17, 2003 -- Opiate addicts treated with a combination of lofexidine and an opiate antagonist are more likely to remain opiate-free and suffer no significant adverse effects, according to a pilot study performed at Yale University School of Medicine and presented at the College on Problems of Drug Dependence's 65th Annual Scientific Meeting.

"Preventing relapse and reducing stress associated with relapse is vital to the overall success of an opiate addiction treatment program," said Rajita Sinha, PhD, Associate Professor, Department of Psychiatry, and Director of the Substance Abuse Treatment Unit at Yale University, who conducted the study. "The addition of lofexidine proved to be effective in ensuring that trial subjects complied with their treatment regimens and remained on the path to becoming opiate free."

Lofexidine, an alpha-2-adrenergic agonist, is a non-opiate, non-addictive treatment that reduces the symptoms associated with withdrawal such as chills, sweating, stomach cramps, emesis, diarrhea, muscle pain, and runny nose and eyes. Lofexidine has been available in the United Kingdom since 1991 and is marketed under the name BritLofex by Britannia Pharmaceuticals.

In the two-phase, 8-week Yale study, researchers sought to evaluate how the addition of lofexidine would affect subjects involved in orally administered opiate antagonist treatment. The opiate antagonist used in the study is a drug prescribed to help people maintain abstinence after they have detoxified (withdrawn) from heroin or other opioids.

In Phase I of the study, subjects were given varying doses of lofexidine in combination with the opiate antagonist. Seventy-two percent of subjects completed the four-week phase and the lofexidine/opiate antagonist combination was found to be tolerable and without any significant adverse events.

In Phase II, subjects were randomized to either remain on lofexidine or be tapered to placebo, in a double-blind placebo controlled manner, while remaining on a consistent dose of the opiate antagonist. Researchers found that subjects treated with the combination lofexidine/opiate antagonist were significantly more likely to remain opiate-free, were more compliant with taking the daily opiate antagonist, and had decreased cravings and lower perceived stress as compared to the subjects who received the placebo.

"The fact that the majority of subjects experienced no side effects or withdrawal symptoms with lofexidine is extremely encouraging," added Thomas Kosten, M.D., Professor, Department of Psychiatry, Yale University, and a senior investigator on the pilot trial. "This pilot study has prompted discussions of future studies to further investigate lofexidine's capabilities in the treatment of opiate addiction."

In the UK, BritLofex is a leading detoxification agent with more than 20,000 detoxifications carried out per year and is also used in outpatient settings, providing another option for areas where treatment clinics are not available.

Last April, a National Institute on Drug Abuse sponsored study was halted, i.e., a Phase III trial that was investigating the use of BritLofex for the treatment of opiate withdrawal symptoms in opiate dependent individuals was stopped due to the overwhelming evidence of efficacy in the BritLofex treatment group as compared with a placebo group. After a regularly scheduled review of the trial, the Data Safety Monitoring Board determined that due to the overwhelming efficacy demonstrated by BritLofex, it would be unnecessary and unethical to the placebo group to continue the clinical trial. Britannia is currently seeking a licensing partner for BritLofex in the United States.

With the exception of the opiate antagonist used in the study (which is associated with adherence problems in this population), no other medication has been found to prevent relapse to heroin besides lofexidine.

Source: Britannia Pharmaceuticals

Posted: June 2003