An attempt by Nabi to develop a new nicotine vaccine failed decisively in clinical studies, chilling the field for researchers who once dreamed of coming up with a better way to break a habit that can kill people through any of 8 different cancers. But now a team at Scripps Research Institute believe they've cracked the biologic code that defeated NicVAX and discovered how you could develop a vaccine that works.
The promise of a nicotine vaccine is in coming up with a jab that would generate antibodies against nicotine molecules, preventing them from entering the brain and giving smokers what their bodies crave. In the last attempt they used a derivative of nicotine called haptens to attach to a protein to spur the immune response. Withdrawal would still occur, but there would be no way to satisfy the craving by lighting up.
The problem in the past, say these investigators, is there are two "mirror" forms of nicotine, which they describe as left and right-handed. The vast majority of the nicotine in tobacco is left handed, but the earlier vaccine generated antibodies that targeted both, creating a lot of wasted effort that helped defeat the effectiveness of the vaccine.
In this new study researchers were able to stick with left-handed haptens, comparing it to the mix of left and right, and found in rat models that the left-handed approach worked much more efficiently, spurring the creation of four times as many antibodies directed against the left-handed form of nicotine in tobacco. And the work might also apply to other vaccine programs for cocaine or heroin.
"This shows that future vaccines should target that left-handed version," said researcher Jonathan Lockner, the first author of the new paper. "There might even be more effective haptens out there."
- here's the release