Smoking vaccine 'a step closer'

[Guest guest]

Taken from:http://news.bbc.co.uk/1/hi/health/3092690.stm

 

[lay person version-see below for 'doc' version-Atti]

 

Early trials of a vaccine which could help people to give up smoking

are proving promising, say scientists. Xenova, the British-based

company behind the vaccine, which may also help cocaine addicts,

started testing it two years ago.

 

Dr Campbell Bunce, a scientist at the company, told the Science

Festival at Salford University that it had proved safe and well-

tolerated. The vaccine works by stopping nicotine or cocaine from

entering the brain.

 

Stop cravings

 

As a result, these drugs are no longer able to stimulate the reward

centres in the brain that cause cravings.

 

The vaccine stimulates the body's immune system to create antibodies

which bind nicotine or cocaine in a person's bloodstream, preventing

it from travelling into the brain.

 

It could be given to people who are having problems kicking their

smoking or cocaine habit.

 

In theory, it could also be given to young children to prevent them

from taking up these habits in the first place.

 

" You can imagine it being used by parents of adolescents, who might

want their children to be protected against a drug-taking habit, "

said Dr Bunce.

 

" That is something with ethical considerations that we would have to

consider. " The vaccine has so far proved safe to use on both smokers

and cocaine users.

 

Scientists are now planning to test how effective it is. Trials on

cocaine users are expected to start later this month. However,

cocaine users have reported that the immunisation reduced the sense

of euphoria they felt after taking the drug.

 

Relapse

 

Dr Bunce said he did not envisage the vaccine stamping out cravings

for cigarettes straight away. Nor would it alleviate the withdrawal

symptoms associated with giving up smoking, such as anxiety and

depression.

 

But the vaccine could help to ensure that people who quit never take

the habit up again. " Often an ex-smoker will relapse at a party, in

a moment of weakness, " said Dr Bunce.

 

" Hopefully, the presence of these antibodies will reduce the hit of

the cigarette and that desire for another cigarette will be

significantly blunted. "

 

One possible concern, he said, was that people might be tempted to

smoke more to get the same " buzz " they were used to. It is not yet

known whether this could happen.

 

A spokesman from the anti-smoking group ASH said it would welcome

the introduction of a vaccine to help people kick the habit. " People

who try to give up smoking can find it very difficult, " he told BBC

News Online.

 

" A vaccine could help these people or people who have consistently

failed to give up. " But as long as it is safe, it should be seen as

an extension of the existing nicotine replacement therapies.

 

" We would not support vaccinating people to stop them from smoking. "

 

 

 

Taken from the company that makes the vaccine Xenova:

http://www.xenova.co.uk/dc_ta_nic.html

 

TA-NIC

 

Background

 

Product

TA-NIC

Indication

Prevention of smoking relapse

Design

Vaccine (protein conjugate)

Status Phase I

 

Xenova is developing a therapeutic vaccine, TA-NIC, for the

treatment of nicotine addiction. Over 1 billion people worldwide

smoke tobacco products (World Health Organisation), resulting in an

estimated 3 million deaths annually (American Cancer Society, 1996)

from smoking-related disease.

 

Nicotine stimulates the release of neurotransmitters which

give rise to positive feelings (pleasure, relaxation, lack of

anxiety, suppressed appetite, improved concentration) which are

reinforced with each cigarette. Regular smoking is associated with

an increased risk of cardiovascular damage, respiratory disease, and

a higher incidence of cancers of the mouth and lung. Women who smoke

during pregnancy put the health and lives of their unborn children

at risk.

 

Despite the known health risks, many people who want to

give up smoking cigarettes (or other tobacco products) find

it very difficult to do so, with approximately 3% of smokers in the

US succeeding annually (Center for Disease Control and Prevention,

1997). Smoking cessation is difficult to achieve

due to the addictive properties of nicotine and the unpleasant

withdrawal symptoms (irritability, lack of concentration,

weight gain, nicotine craving).

 

Current treatment focuses on using nicotine replacement therapy

(NRT) via transdermal patches, chewing gum, inhalers, to address the

withdrawal symptoms and is often used in conjunction with smoking

cessation clinics or support groups.

A nicotine-free alternative is the anti-depressant, bupropion, which

is now indicated in some countries for smoking cessation.

 

The active ingredient of the TA-NIC vaccine is a protein conjugate:

nicotine derivative coupled to recombinant

cholera toxin B (rCTB). The finished TA-NIC vaccine consists

of the protein conjugate adsorbed onto aluminium hydroxide gel

adjuvant in a sodium phosphate buffer containing mannitol. The

vaccine is administered by intramuscular injection and it

is anticipated that a short course of injections will be

required to induce antibody responses.

 

TA-NIC vaccine is designed to act as follows: the nicotine

derivative carried by an immunogenic protein will prime the immune

system to produce anti-nicotine antibodies. On smoking a cigarette,

nicotine readily enters the bloodstream where it is expected that it

will encounter and bind to these antibodies. The antigen-antibody

complex is too large to cross the blood-brain barrier, so the

pleasurable stimulus which usually accompanies smoking will be

absent or reduced. It is anticipated that this will help to break

the habit.

 

TA-NIC vaccine offers a new approach where the treatment consists of

a short course of intramuscular (im) injections rather than daily

administration of NRT or bupropion. It is anticipated that TA-NIC

vaccine would be used in combination with other pharmaceutical-based

approaches. The support and advice provided by smoking cessation

centres could improve the chances of giving up smoking.

 

Clinical Status

 

The start of the Phase I clinical testing of TA-NIC was announced in

September 2001 and the results in June 2002. This was the first ever

evaluation of an anti-nicotine vaccine in man. TA-NIC was shown to

be safe and well-tolerated both systemically and locally and was

shown to generate a nicotine-specific antibody response.

 

The double-blind, randomised, placebo-controlled study was designed

to assess the safety, tolerability and immunogenicity of TA-NIC in

both smokers and non-smokers. The vaccine was administered by intra-

muscular injection and investigated at two different dose levels in

a variety of dosing regimens.

 

Comments by Attilio:

 

Does this spell the end for the need of acupuncture to treat

addiction (there's also a cocaine version coming out)? Any comments?