New vaccine to stop cocaine addiction

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New vaccine to stop cocaine addiction

Monday, 14-Jun-2004


Xenova Group plc has announced the presentation of results of two dose escalation Phase II studies of TA-CD, a vaccine being developed for the treatment of cocaine addiction, at the College on Problems of Drug Dependence 66th Annual Scientific Meeting in Puerto Rico, June 12-17. Presented by Dr Bridget Martell, the trials were carried out by Professor Thomas Kosten and his team at Yale University School of Medicine.

The two open-labelled, dose-escalation studies carried out on an out-patient basis, evaluated safety, immunogenicity and clinical efficacy of TA-CD in a total of 22 cocaine users. One of the two studies comprised nine cocaine dependent subjects receiving the TA-CD vaccine and assessed for relapse prevention; these subjects were required to have been free of cocaine use for the two weeks prior to entering the study. The second study included 13 cocaine dependent subjects for abstinence initiation, who were not required to have negative urine cocaine tests prior to enrolment.

Subjects received between three 100 mcg doses and five 400 mcg doses of the TA-CD vaccine (up to 2000 mcg in total). TA-CD was well tolerated in the 20 subjects who completed the two studies.

Results from both studies showed that the maximum mean antibody response occurred between 70 and 90 days post vaccination with specific cocaine antibodies persisting for at least six months. Eight subjects also received a booster 15-18 months post vaccination with TA-CD, all of whom showed increased levels of antibodies two to four weeks later.

Three quarters (75%) of the relapse prevention study group maintained abstinence from cocaine use during the 12-week study duration with 100% relapsing after 12 months when antibody levels had dropped.

In the abstinence initiation study group, 58% achieved and maintained abstinence during the 12-week study and 42% continued to be cocaine free after six months.

The authors additionally reported that the likelihood of using cocaine decreased in those subjects who received a more intense vaccination schedule and as a result were observed to produce higher levels of anti-cocaine antibodies. 88% of subjects in one study and 63% of subjects in the other, who relapsed within six months, reported a reduction in the euphoric effects of cocaine.

Bridget Martell, MD, MA, Associate Research Scientist at Yale University and involved in the TA-CD trials said, "Cocaine dependent users have a serious need for assistance with achieving and maintaining abstinence. We are impressed with these results which, although on a comparatively small number of subjects, are particularly significant as a number of addicts receiving the TA-CD vaccine were able to remain abstinent during the study periods."

David Oxlade, Chief Executive Officer of Xenova said, "These very encouraging results give a strong indication of proof of concept for the TA-CD cocaine vaccine and further validate its potential in assisting cocaine addicts to achieve abstinence."

This study was supported by the US National Institute of Drug Abuse (NIDA). NIDA has also supported earlier clinical work on TA-CD. NIDA has no rights to the commercialisation of TA-CD nor is funding required to be repaid by Xenova.

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British drug company announces cocaine 'vaccine'

A British drug company has announced that one of its drugs has helped cure cocaine users of their addiction, in US-based clinical studies.

Nearly half of addicts who participated in a clinical trial of the "vaccine" were able to stay off cocaine for six months, David Oxlade, chief executive of Xenova, said on Monday.

"The vaccine for cocaine addicts works in very much the same way a regular vaccine works," Oxlade told BBC radio.

According to the company, its anti-cocaine drug blocks the high experienced by users, instead of fighting the chemical addiction itself. Without the high, the cravings for the stimulant apparently diminish as well.

Oxlade said his company's product works by attaching cocaine to a larger protein molecule in the body, which then stimulates the immune system to produce anti-bodies that recognize the cocaine and block its effect.

"It stops the cocaine from being able to get across from the blood into the brain, which is where you get the high and, of course, where you get the addiction," he said.

The success rate in the clinical trial was "quite remarkable" in its ability to keep addicts off the highly addictive drug for six months, he said.

The Guardian newspaper reported the study had taken place at Yale Medical School using only 22 regular cocaine users and recovering addicts.

It said Xenova had embarked on a larger study of 130 patients and would report its findings in 2006.
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British drug company announces cocaine 'vaccine'
Agence France-Press (AFP)
Mon, June 14, 2004

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Very interesting, I wonder how effective this would be to smoking and injecting, would the anti-bodies have enough time to counteract the instant introduction of cocaine?
 
I just hope this is limited to people who want to quit and parents don't jump on this and use it on kids. The US really scares me.
 
you dont get high; but you still must get the cravings for the drug, right?

That must suck. its like being forced to quit.
 
Just wait for the day when you have to choose between a vaccine for your drug of choice and a huge jail term.
 
So maybe one day there will be a multi-drug vaccine that has the ability to prevent you from getting high for the rest of your life on any drug?.....Thats scary
 
^ cheaper alternative to rehab... but doubtful that there will be mult-drug vaccines or vaccines for other drugs, for example pain killers as they have a legitimate use.
 
Note from a similar article:

Some experts are sceptical that a cocaine vaccine could ever be effective enough. A line or two of cocaine contains around 200mg of drug, a large amount for the immune system to block. "Just working out the maths - you'll need so many of these antibodies to scavenge the cocaine as it flows to your brain, you're going to struggle to make it," said Professor John Henry, an expert in illicit drugs at St Mary's hospital in London.

http://www.guardian.co.uk/uk_news/story/0,3604,1238955,00.html
 
How cocaine vaccine blocks the high

Ian Sample, science correspondent
Tuesday June 15, 2004
The Guardian

The idea behind a cocaine vaccine is simple: trick the body into thinking the drug is a threatening disease. If a vaccinated person then takes the drug, their immune system will mop it up before it gets into the brain and its effects take hold. In theory, at least, the hit from the drug never arrives.
Most recreational drugs, including cocaine, heroin and ecstasy, consist of small molecules that can easily slip past the body's immune system and get into the brain. When cocaine enters the brain, it leads to a surge in the feelgood chemical dopamine.

To make a cocaine vaccine, Xenova Group scientists tag a derivative of cocaine to a harmless, but much larger cholera protein.

When the vaccine is injected, the immune system recognises the cholera protein as "foreign" and starts churning out antibodies. While some of these antibodies target the cholera protein, others will attack cocaine.

According to Xenova, after a course of injections spanning from four to six weeks, levels of the antibodies in the blood should be sufficient to block the effects of cocaine.

Once vaccinated, any cocaine that does get into the bloodstream will quickly be covered in antibodies that make the drug too large to pass across a natural filter called the blood-brain barrier that protects the brain.

"The result is, you don't get the high," said Xenova's director of clinical development, Simon Long.

Preventing a drug-induced high could help those who want to stay off the drug, though it will do nothing to ease withdrawal.

Some experts are sceptical that a cocaine vaccine could ever be effective enough. A line or two of cocaine contains around 200mg of drug, a large amount for the immune system to block. "Just working out the maths - you'll need so many of these antibodies to scavenge the cocaine as it flows to your brain, you're going to struggle to make it," said Professor John Henry, an expert in illicit drugs at St Mary's hospital in London.

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i wonder if there's been a study of whether these users have a reduced capacity for pleasure after the vaccine.. a mult-drug vaccine as posited above would probably render you incapable of many emotional states. since drugs mimic chemical reactions that take place naturally in the brain, a multi-drug vaccine would almost surely prevent chemicals produced naturally from crossing the blood-brain barrier as well. everybody'd be feeling uncomfortably numb i'd think.
 
since drugs mimic chemical reactions that take place naturally in the brain, a multi-drug vaccine would almost surely prevent chemicals produced naturally from crossing the blood-brain barrier as well.
Click to expand...

As far as vaccines go, I doubt many if any at all would interfere with normal brain functioning.

Endorphine, heroin, fentanyl and methadone are all structurally different, for instance. If you made a heroin vaccine, the brain's natural endorphine as well as fentanyl and methadone should all work just fine. The vaccine would create antibodies that wouldn't recognize the other opiate agonists.

Now if you simply used an antagonist to block, lock or empty opiate receptors, sure, it's going to mess things up.

In the case of cocaine, it's not similar enough to anything naturally occuring in the brain that antibodies would detect.

Although I'm not sure about naturally occuring cannibinoids in the brain that are stimulated and cause euphoria after an activity like jogging.

As a reference, simply keep in mind different strains of influenza. Even multi-strain flu vaccines don't work against all strains of influenza.

Personally, if such vaccines were proven to be effective and not have unwanted side effects, I wouldn't mind if they were used on repeat criminal offenders whose crimes were drug related. I'd rather see someone not be able to get high and stay out of jail rather than see someone stealing to support their habit or getting in fights or auto accidents or whatever everytime they got out of jail. It's not like people like this are going to be hurt if they can't get high. Heaven forbid someone be forced to break a destructive cycle of addiction and turn their lives around to become functional and productive citizens.

I'd also gladly take a nicotine vaccine if it didn't have unpleasant side-effects.
 
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