New Investigational Nicotine Vaccine May Help Prevent Smoking Addiction, Relapse

08/21/09  Portland, OR

Relapse rates for smokers using existing anti-smoking treatment therapies can be as high 90 percent

Oregon Health & Science University is among 22 centers participating in a Phase III clinical trial to determine whether a new investigational smoking cessation aid called NicVAX is safe, effective and capable of stimulating an immune response.

OHSU was one of nine centers to participate in the earlier Phase II trial of NicVAX, a proprietary investigational vaccine developed by Nabi Biopharmaceuticals.

Nicotine is a mind-altering compound that easily crosses the blood brain barrier, a network of blood vessels that makes it difficult for toxic substances to enter the brain. Because nicotine molecules are extremely small, they don’t stimulate an immune or antibody response by themselves. Once in the brain, nicotine binds to specific receptors that trigger the release of a number of neurotransmitters, such as dopamine, that change the way the smoker feels.

“Smokers continue to smoke even when they know it’s harmful because of these ‘brain effects,’” explained David Gonzales, Ph.D., OHSU principal investigator and clinical investigator in medicine (pulmonary and critical care medicine) at the OHSU Smoking Cessation Center, OHSU School of Medicine. “While a smoking cessation medication such as varenicline prevents nicotine from binding to receptors once it is in the brain, NicVAX is designed to block nicotine before it enters the brain.”

The vaccine stimulates the body’s immune system to produce antibodies that bind to or capture the nicotine molecules in the bloodstream, creating a complex that is too large to cross the blood-brain barrier. As a result, many of the expected rewards from smoking are blocked, making it easier for the smoker to become and remain abstinent. Because antibodies circulate in the bloodstream for an extended period of time, researchers hope the vaccine also will help smokers maintain long-term abstinence from cigarettes.

“A nicotine vaccine to help smokers quit smoking is a novel and exciting direction for smoking cessation treatment,” Gonzales said. “Unlike medication treatments where the planned quit day is immediate or within one or two weeks of starting medication, the planned quit day for those taking the vaccine is a number of weeks after the first injection. The longer lead-in to the quit day is to allow the antibody levels to increase. For some smokers, this more gradual run in for quitting may be more appealing.”

Because a vaccine is not a drug and not metabolized, explained Gonzales, there is no expected risk of vaccine/drug interactions. Should the results of the study demonstrate that the vaccine is safe and effective and the FDA grants approval, some smokers may be able to use a cessation aid for the first time.

Approximately 1,000 male and female smokers aged 18 to 65 will take part in the study for a 12-month period; about 50 will be enrolled at OHSU. Half of study participants will receive the vaccine and half will receive a placebo. At the end of the 12-month observational period, Gonzales and colleagues will evaluate participants’ overall abstinence based on self-reported cigarette use and exhaled carbon monoxide.

In addition, the researchers will assess the safety and immune system response to NicVAX at various intervals throughout the study and determine whether the vaccine has an effect on withdrawal symptoms, cigarette consumption, smoking satisfaction and nicotine dependence.

Smokers interested in learning whether they qualify for study should call 503-494-0503.

This study is funded in part with a $10 million grant from U.S. National Institute on Drug Abuse, part of the National Institutes of Health.

About Tobacco Use
According to the Centers for Disease Control and Prevention, smoking is the leading cause of preventable death in the United States, accounting for 443,000 deaths annually. The CDC estimates that, among the 45 million adult smokers in the United States, 70 percent want to quit, but fewer than 5 percent of those who try to quit remain smoke-free after 12 months. For more information about smoking and tobacco use, visit the OHSU Smoking Cessation Center Web site: www.ohsu.edu/smokingcessation/

About Oregon Health & Science University
Oregon Health & Science University is the state's only health and research university and Oregon's only academic health center. OHSU is Portland's largest employer and the fourth largest in Oregon (excluding government). OHSU's size contributes to its ability to provide many services and community support activities not found anywhere else in the state. It serves patients from every corner of the state, and is a conduit for learning for more than 3,400 students and trainees. OHSU is the source of more than 200 community outreach programs that bring health and education services to every county in the state