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Tuesday, October 19, 2010

Fighting the Drug Wars

About 810,000 people in the U.S. are addicted to heroin, and another 1.85 million either abuse or are dependent on opioid painkillers. (Rita Rubin, "FDA OKs Vivitrol to Treat Heroin, Narcotic Addictions," USA Today, October 14)

The overall cost of prescription opioid abuse, including such factors as medical care, loss of productivity and criminal activity, has been estimated at $9.6 billion and the cost of heroin addiction has been estimated at $22 billion(Melly Alazraki, "Alkermes Opioid Addiction Drug Vivitrol Gains FDA Panel Support," Daily Finance September 17 2010)

"Opioid addicts are notoriously bad at complying with their medication. They like to take drug holidays. They like to party on the weekend," says Dr. Katherine Beebe of Titan Pharmaceuticals, which is developing the Probuphine implant.

Long-acting options may help make substance abuse treatment more a part of mainstream medicine. "To have these medications work effectively, you need to stay on them for long periods of time," says Dr. Patrick O'Connor of Yale University School of Medicine. "We are really struggling to get the public and physicians to think of this more like a standard chronic disease — like diabetes, like cancer, like chronic lung disease — and not apply a special stigma to it."

Scientists who have developed new treatments for addiction to heroin or narcotic painkillers promise longer-lasting relief that may remove some day-to-day uncertainty of care: A once-a-month shot is now approved and a six-month implant is in the final testing phase. ("Longer Lasting Options To Treat Drug Addiction," Fox News A.P., October 18 2010).

The main treatments options up to now have been once-a-day medications — controversial methadone or a tablet named buprenorphine. These act as substitutes for the original drug, to suppress withdrawal and craving without the high. Skipping a dose risks a relapse, but summoning the daily willpower to stick with treatment is "a formidable task," says National Institute on Drug Abuse director Dr. Nora Volkow.

Both methadone and buprenorphine require close monitoring because they, too, can be abused, and some treatment programs won't use them because "their perception is you're changing one drug for another," says Volkow.

Which new treatment works the best? It's far too early to call for the verdict. But, early next year, NIDA will directly compare once-a-month Vivotrol to once-a-day buprenorphine and behavioral therapy alone to help tell.

1. Vivotrol

Vivitrol is an extended-release formulation of naltrexone administered by intramuscular injection once a month. Naltrexone works to block opioid receptors in the brain, ensuring that patients will not feel any effects if they attempt to use while being treated. Over time, their cravings diminish. By contrast, methadone is used as a replacement drug for opiates -- users can still be addicted to it -- and buprenorphine (many believe) blocks some receptors, but not all. ("FDA Okays Vivitrol For Opiate Addiction," Join Together, October 13 2010) 

The drug is designed to be used for patients who have already gone through opioid detoxification and no longer have any opioids in their system. It should not be given to patients who have positive urine screens. Patients who are given Vivitrol may be more sensitive to opioids at the time their next scheduled dose is due. This sensitivity can make patients more susceptible to an accidental overdose if they restart opioid use upon missing a dose of Vivitrol or after treatment with Vivitrol has ended. (Ramona Bates, "Vivitrol Approved by FDA for Opioid Treatment," EMax Health, October 13 2010)

In a study of 250 opioid addicts in Russia, more than half of Vivitrol recipients stuck with therapy for the six-month trial. Better, 36 percent stayed completely drug-free, compared with 23 percent who received dummy shots. (Fox News) Vivotrol was approved by the FDA to treat alcohol dependence in 2006. The FDA has now approved Vivitrol to treat and prevent relapse after patients with opioid addiction have undergone detoxification.

Doctors can prescribe drugs "off-label," but few have used Vivitrol, which lists for $1,100 per shot, to treat opioid addiction, Alkermes CEO Richard Pops says. "This is such a new market." The drug claims to be non-addictive.

2. Probuphine

A match-stick size implant that lasts for up to six months as it slowly oozes a low dose of buprenorphine into the bloodstream, to keep cravings tamped down.A large study published last week deemed the implant, called Probuphine, promising — just over a third of those patients, too, tested drug-free. Ongoing research partly funded by the government should show next spring if it's ready for FDA evaluation..

Buprenorphine (BPN) is an approved treatment for opioid dependence, however, in taking oral tablets, patients experience withdrawal and cravings when the variable BPN levels in the blood are low. Probuphine is an implant placed just beneath the skin that contains BPN. It is designed to provide 6 months of stable BPN blood levels.
Titan Pharmaceuticals, Inc. announced their Phase 3 randomized, placebo-controlled clinical trial of Probuphine in the Journal of the American Medical Association (JAMA).  The article highlighted data from the 163-patient trial, which showed that "patients receiving Titan's Probuphine implant had significantly less illicit opioid use, experienced fewer symptoms of withdrawal and craving, stayed in treatment longer and had greater overall improvement when compared to placebo patients over the course of the 24-week study." (J. White, J. Bell, JB Saunders, et al.,  Burprenorphine Implants for Treatment of Opioid Dependence: A Randomized Controlled Trial," JAMA, October 13 2010) 

The National Institutes of Health has supported the study by awarding the company a two year $7.6 million Research and Research Infrastructure Grand Opportunities grant through the American Reinvestment and Recovery Act of 2009, with the first year award of approximately $5.6 million now available to Titan. This grant covers a little over half the cost of the study and it will be administered by the National Institute on Drug Abuse.

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