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Anti-Drug Vaccines Hold Promise – But Little Profit

MEXICO CITY, Feb 10 2012 (IPS) - Vaccines against drug addiction appear to be a better strategy than the repressive worldwide “war on drugs”, but first they must overcome resistance from pharmaceutical laboratories and secure financial backing, scientists say.

Experimental trials against cocaine and heroin addiction are under way in Mexico and the United States, but two or three more years of work are needed to prove that the treatment is viable. Ethical aspects must also be resolved, such as compulsory medication for addicts and permission for use in children.

“Different delivery methods need to be designed. The pleasurable effect of drugs needs to be eliminated, which is feasible. But it will have to start being done in under-age children, and that raises a number of legal and ethical issues,” Dr. Rogelio Rodríguez told IPS.

At his private clinic, Rodríguez offers serum treatments for cocaine and alcohol dependency, combined with psychotherapy. For seven days, at a cost of 64 dollars a day, patients receive doses that lead to rejection of the addictive substance and its abandonment.

The Mexican health ministry patented a vaccine against heroin that has been successfully used in mice, and is about to enter the phase of clinical trials in humans, for which the government is seeking international funding.

The human immune system cannot detect drug molecules because they are too small, but by attaching them to larger molecules the body is “tricked” into making antibodies that recognise the drug molecules, bind to them and prevent access to the brain. The patient therefore does not feel the drug’s effects, and stops using it.

In Mexico there were at least 465,000 drug addicts in 2008, according to the National Survey on Addiction that year. A more recent edition of the survey is being compiled.

The survey reports that the cumulative incidence (lifetime risk) of consumption of addictive illegal and medical drugs in the rural and urban population aged 12-65 was 5.7 percent. Use of illegal substances, like marijuana, cocaine, heroin and methamphetamines, had a cumulative incidence of 5.2 percent in this population.

Marijuana and cocaine were the most heavily consumed, with a lifetime risk of 4.2 percent and 2.4 percent, respectively, followed by inhaled drugs, amphetamines and heroin.

The vaccine “is promising for users wanting help to stop substance abuse. But it’s not a cure, nor a complete blockade,” professor Frank Orson of the Department of Pathology and Immunology of Baylor College of Medicine, in the southern U.S. city of Houston, told IPS.

In their paper titled “Anti-cocaine Vaccine Development”, published in 2010 in Expert Review of Vaccines, Orson and his U.S. colleagues Berma Kinsey and Thomas Kosten emphasised the “urgent need for new treatments for cocaine addiction, especially since no effective pharmacological interventions are available for cocaine, in contrast to morphine/heroin addiction.”

The earliest experiments with vaccines against morphine and heroin date back to the 1970s, but then interest faded, perhaps because of the availability of methadone to treat heroin addicts. Research was renewed in 1992, when the generation of anti-cocaine antibodies in vaccinated mice was reported as a potential preventive treatment.

After taking office in December 2006, Mexican President Felipe Calderón deployed thousands of soldiers and police to fight drug trafficking in a repressive campaign that has left more than 47,000 dead, according to the latest government figures, although journalists put the death toll at over 50,000.

A preventive clinical approach is therefore an urgent priority, although vaccine development requires financial backing for production on an industrial scale.

“It’s not a profitable product for the pharmaceutical industry, and the same is true for many other diseases. The state would have to subsidise it. We have already heard more than once that a vaccine is on the way, but then nothing happens,” said Rodríguez, who tried unsuccessfully to introduce his treatment in Mexico City prisons – “but there were too many conditions and requirements.”

The National Survey on Addiction (to substances including alcohol, tobacco, soft and hard drugs) found that teenagers are the age group most at risk of becoming addicted, due to excessive consumption. According to the study, 35.8 percent of teenage respondents had used addictive substances, compared to 24.6 percent of adults aged 18-25, and 14.5 percent of over-25s.

It also found that half of those who smoked marijuana had first tried it before they were 18, while only one-third of cocaine users had consumed it before they were 18. Adults aged 18-25 who used drugs had a different profile, as they tended to be over 18 when they started to consume cocaine, hallucinogens and heroin.

“It’s unlikely that pharmaceutical companies will commit to commercial production (of the vaccine). The industry will need government support, since the market is small, and those needing the treatment generally do not have a lot of money available for it,” Orson said.

Vaccine treatment for addiction poses some thorny dilemmas, such as whether parents would have to give permission for their children to be inoculated, whether the state should have the power to compel treatment of under-age offenders, and the issue of confidentiality of the personal details of those vaccinated.

“Better vaccines or newer methods will not be the end of the game for treating substance abuse, however. The motivated cocaine addict will need other interventions, such as therapy and rehabilitation programmes, in order to overcome this seductive addiction,” Kinsey, Kosten and Orson’s paper says.

“Anti-drug programmes in schools should be strengthened, as cocaine addiction often starts before 20 years of age,” they say. They also recommend that the criminal justice system should reconsider the wholesale incarceration of cocaine users, and offer help rather than punishment.

The National Survey on Addiction found that only 16 percent of drug users seek treatment, and that fellowship groups like Narcotics Anonymous are very important resources.

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