VACCINE MAY HELP TREAT COCAINE ADDICTION

NEW YORK (Reuters Health) - An experimental vaccine that blocks the
effects of cocaine on the brain by tying it up in the bloodstream may
help treat cocaine abuse, scientists report.

Although the vaccine has so far only been evaluated in rats, testing
in humans is due to begin soon.

"We believe the vaccine will protect addicts at weak moments when
they have the urge to get high," Dr. Kim D. Janda told Reuters
Health. "If we can prevent the high, we can prevent relapse, and this
would speed the process of kicking the addiction."

The vaccine is a derivative of cocaine attached to a larger protein.
Injecting it into the bloodstream stimulates the immune system to
produce antibodies against cocaine. The antibodies work by attaching
themselves to cocaine molecules in the blood, stopping them from
reaching receptors in the brain, thus blocking their effects.

This is not the first time that a cocaine vaccine has been tried, the
authors explain, but earlier vaccines did not generate a powerful
enough immune reaction to lock up all the cocaine in the blood.

Janda and colleagues from The Scripps Research Institute in La Jolla,
California, tested their new vaccine--designed to generate a stronger
cocaine-blocking response--in rats. They gave rats cocaine and used
the rodents' hyperactivity as a measure of the effects cocaine was
having on their brains.

When the researchers then gave some of the rats the vaccine,
hyperactivity dropped to about one-quarter the level seen before
vaccination, according to the report in the February 13th Proceedings
of the National Academy of Sciences (news - web sites).

Other measures of cocaine activity also differed substantially between
vaccinated and unvaccinated rats, the report indicates, and these
differences persisted through several cocaine challenges.

"The current vaccine provides a much longer lasting effect than our
previous vaccines," Janda told Reuters Health, "suggesting that
boosting requirements would be minimal and the antibody circulation
time would be increased."

The new vaccine should be in clinical trials soon. "A company called
Drug Abuse Sciences in Mountain View, California, will be moving this
forward into the clinic. They have licensed our patents in the area,"
Janda said.

SOURCE -- Proceedings of the National Academy of Sciences 2001;98:1988-1992.