Novartis, a leading health care products company, called it quits on its NIC002 nicotine vaccine project, which failed badly three years ago in Phase II studies undertaken with an eye toward government approval. Novartis said it would terminate the license it has for the NIC002 vaccine with Cytos Biotechnology, for which it paid $38 million in 2007. The Phase II study “showed formation of nicotine-specific antibodies in patients but did not meet its primary endpoint of increased smoking cessation,” according to Genetic Engineering and Biotechnology News
Much the same arc was followed by Nabi Biopharmaceuticals, which announced in 2011 that its vaccine, NicVax, had failed to outdo placebos in Phase III clinical trials—the only addiction vaccine to advance that far in the approval process. The company’s own studies had shown happier results in 2007. In regulatory filings, the company claimed that the NicVax vaccine triggered a reliable antibody response, thus preventing nicotine molecules from reaching the brain. The antibodies bind with the nicotine molecules, making nicotine too large to cross the exceedingly fine blood-brain barrier of the brain. Roughly 15 per cent of smokers who received injections of NicVax were nicotine-free after one year in company-funded studies. For comparison, early studies of Chantix as an anti-smoking medication show a quit response rate in the range of 20 per cent for heavy smokers.
As I have previously written, the idea of vaccinating for addictions is not new. If you want the body to recognize a nicotine molecule as a foe rather than a friend, one strategy is to attach nicotine molecules to a foreign body--commonly a protein that the body ordinarily rejects--in order to switch on the body’s immune responses against the invader. A strong advantage to this approach, say researchers, is that the vaccinated compound does not enter the brain and therefore is free of neurological side effects.
There remain a wealth of questions related to the effects of long-lasting antibodies. And it is sometimes possible to “swamp” the vaccine by ingesting four or five times as much cocaine or nicotine as usual.
Drugs that substantially reduce a smoker’s craving for nicotine, like Chantix, may yet prove to be a more fruitful avenue of investigation. While several anti-craving medications have been approved for use by the Food and Drug Administration (FDA), no vaccines have made it onto the approved list. However, as the Genetic Engineering article reminds us, “all is not lost for the vaccine yet: in November of 2010, Duke University, in collaboration with Wake Forest University, commenced a Phase II clinical study with NIC002 performed with 65 smokers that aims to assess how nicotine antibodies, induced by vaccination, affect the pharmacokinetics of nicotine during cigarette smoking. The study is being conducted in the United States with funding from the NIH.”
Photo: Creative Commons / juliealicea1947
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