A Nicotine Vaccine

At the American Heart Association Scientific Sessions in Orlando this month, investigators from the University of Nebraska presented preliminary data on a brand new approach to smoking cessation - a nicotine vaccine.

The new vaccine (to be called NicVAX, from Nabi Biopharmaceuticals) was tested in a group of 300 patients, who were randomized to receive either the NicVAX or placebo injections (up to 5 shots over 6 months). At 12 months, 16% pf the patients receiving the vaccine had quit smoking, versus only 6% of the patients receiving placebo. This "quit rate" appears to be somewhat better than is typically achieved with currently available therapy, such as nicotine patches or Wellbutrin (bupropion).

The nicotine vaccine works by stimulating the body's immune system to make antibodies to nicotine. The antibodies bind to nicotine in the bloodstream, and prevent it from going into the brain (where its addictive properties are manifested.) Other drugs work by blocking nicotine receptors in the brain itself. Once a person is "vaccinated" against nicotine, the effect is irreversible for up to 12 months.

The nicotine vaccine approach is certainly novel, and may prove to be a major advance in smoking cessation. But don't look for it any time soon. At least two issues will have to be resolved before the FDA approves NicVAX.

First, what happens to the other 84% of patients taking NicVAX - the ones who don't quit smoking? Do they "compensate" for the anti-nicotine antibodies (now present in their bloodstream for 6 - 12 months) by increasing their smoking volume? To satisfy their nicotine urge, wouldn't they now have to increase their nicotine intake to overwhelm the antibodies? (In contrast, patients on Wellbutrin who continue smoking can just stop taking the drug, then continue with their usual smoking habits.)

And second, can the immune-complexes formed by the nicotine+antibody combinations produce any form of immune-complex illness, such as arthritis? While such problems were not seen in this small study, several patients did develop fever and aches - and a large safety study will be required before this question (and other safety questions) are sufficiently answered.

The bottom line on the nicotine vaccine - so far, so good, but a lot more information is needed before the nicotine vaccine can be approved.