A sense of euphoria, relaxation and increased alertness is how nicotine exerts its power over people. UNMC is enrolling people in a national study to evaluate whether a nicotine vaccine can help people quit smoking.
The phase II study, which involves about 10 centers around the country, will evaluate whether a nicotine vaccine made by Nabi Biopharmaceuticals is effective in helping smokers quit, as well as determine the appropriate vaccine dosage.
The Nabi study is funded in part by the U.S. National Institutes of Health.
The nicotine vaccine works in part by reducing the pleasurable effects of smoking and also by reducing withdrawal symptoms, said Stephen Rennard, M.D., Larson Professor of Medicine, UNMC Pulmonary and Critical Care Section, and principal investigator of the UNMC study.
Like vaccines that prevent disease, the nicotine vaccine generates antibodies in the body that attach to nicotine molecules, making them larger and more difficult to get into the brain. It is thought the vaccine blocks the pleasurable effects of smoking as well as the withdrawal symptoms.
UNMC has been involved in previous successful phases of the Nabi vaccine development study. The previous phase II study evaluated whether smokers produced antibodies against nicotine.
Dr. Rennard and his staff will enroll 20 to 40 healthy men and women at least 19 years old, who smoke at least 15 cigarettes a day. Those eligible must have been smoking for at least six months and have not tried to quit in the last six months. Those who have been in a nicotine vaccine study before are ineligible.
He said several other companies are testing nicotine vaccines, one of which also is in phase II studies. He said there’s a lot of interest in nicotine vaccines to quit smoking. How effective they are remains the key question.
Dr. Rennard said NicVax works in two main ways: by reducing the amount of nicotine getting into brain, which reduces or eliminates the pleasurable effects of smoking, and by reducing or eliminating many of the withdrawal symptoms.
“The vaccine prevents or reduces the amount of nicotine crossing into the brain. Nicotine can get into the brain, but it’s so slow that it doesn’t give smokers the kick. The kick smokers get from nicotine depends on how fast nicotine gets into the brain. So the vaccine slows it down,” Dr. Rennard said. “With the vaccine, nicotine is chemically linked to a carrier so the body recognizes it and makes antibodies against the nicotine, much like how the body develops antibodies to things like the flu vaccine.”
In addition to reducing the pleasurable effects of smoking, Dr. Rennard said the nicotine vaccine may reduce the withdrawal effects.
“The speed with which the drug reaches the brain determines the addictive potential. The vaccine not only slows the delivery of nicotine, but serves as a reservoir so when you come off cigarettes, there may be less withdrawal symptoms so it makes it easier to quit,” he said.
Withdrawal symptoms commonly are irritability, insomnia, difficulty concentrating, increased appetite, weight gain, depression, heart palpitations and craving for cigarettes, Dr. Rennard said.
The study will require participants to make about 25 visits to UNMC to provide information, blood and breath samples, as well as receive a vaccine treatment. Researchers will not know if study participants receive the active vaccine or a placebo.
If the results of the study are successful, Nabi will move forward for phase III studies to evaluate the vaccine in a large group of people to determine its safety and effectiveness.
“I think everyone is excited about the nicotine vaccine because it’s a different way to treat nicotine addiction. The vast majority of smokers — 70 percent – want to quit smoking,” Dr. Rennard said. “It’s a disease and people need to realize treatments can help. But more effective treatments are needed. The possibility of a novel treatment offers tremendous potential for people who haven’t been able to quit.
“The vaccine is really very different than all of the other drugs. Theoretically, all the other drugs are designed to work in the person’s brain to affect the nicotine addiction process. They can do that and they can help. The vaccine targets the addicting drug and it seems more appealing to attack the enemy.”
Through Dr. Rennard’s expertise, UNMC has been involved in many national studies that have helped commercialized smoking cessation products such as the nicotine patch, nicotine gum and Zyban and the recently approved Chantix. He is known around the world for his expertise in chronic pulmonary obstructive disease, and has written more than 125 articles and book chapters related to smoking cessation.
For more information about the study, call (402) 559-8296 or e-mail mlcarlso@unmc.edu.