H E A L T H P R O M O T I O N
vaccines for smoking cessation
A recent emerging health
technology bulletin summarizes information about vaccines that are under
development for smoking cessation.
The Canadian Agency for Drugs and
Technologies in Health (CADTH) is an independent, not-for-profit
agency funded by Canadian federal, provincial, and territorial
governments to provide credible, impartial advice and evidence-based
information about the effectiveness of drugs and other health
technologies to Canadian health care decision makers. A recent
emerging health technology bulletin summarizes information about
vaccines that are under development for smoking cessation.
Cigarette smoking is the leading cause of
preventable disease and death in the world. Smoking was responsible for
an estimated 100 million deaths in the 20th century, and is expected to
cause ten times that number in the current century. Smoking accounted
for 16.6% of all deaths in Canada in 2002 a total of 37,209 deaths.
The direct and indirect costs of smoking in Canada have been estimated
at $8 to $11 billion per year. Nicotine, the principal addictive agent in
cigarettes, is a common addiction throughout the world. Existing smoking
cessation therapies are only modestly effective.
Nicotine vaccines produce
nicotine-specific antibodies that bind a substantial proportion of the
nicotine molecules when they enter the bloodstream. The antibody-bound
nicotine molecules are too large to cross the blood-brain barrier, thus
preventing most of the nicotine from entering the brain and exerting its
addictive effects. In immunized individuals, nicotine is also less
available for metabolizing, which markedly slows its elimination. This
may enable smokers to reduce their rate of smoking, as the effect of any
nicotine that succeeds in entering the brain is prolonged. Other
strategies and pharmacological aids that are currently available for
smoking cessation achieve limited success.
Nicotine vaccines are still at the
investigational stage and none have been licensed for use in Canada or
elsewhere. NicVAXฎ received a fast-track designation from the US Food
and Drug Administration (FDA) in February 2006. Trial results from the
NicVAX phase 2 proof-of-concept and optimal-dosing study are expected in
the late 2007. Celtic Pharma anticipates seeking FDA approval for TA-NIC
in 2009. The bulletin summarizes the evidence on three nicotine vaccines
that have reached phase 2 trials.
If a nicotine vaccine is licensed for
smoking cessation, there will likely be significant demand from the
public and health care providers. Given the considerable interest
smokers have in quitting the habit, and the limited effectiveness of
currently available options, many smokers may be anxious to try a new
therapy, even if the likelihood of quitting remains somewhat modest.
Efficacy may ultimately depend on development of vaccine formulations or
dosing schedules that permit all vaccinated individuals to achieve high
antibody levels. Vaccines also offer the convenience of avoiding daily
dosing and, based on the limited preliminary evidence available, adverse
effects appear to be relatively minor.
For the full bulletin or other reports
of interest feel free to visit the
CADTH website or
contact Cindy Mosher, CADTH Liaison
Officer in Newfoundland and Labrador or phone: (709)-777-8740.
Cigarette smoking is the leading cause
of preventable disease and death in the world.
Nicotine vaccines produce antibodies
that bind nicotine, the chief addictive agent in cigarettes, and
prevent it from entering the brain.
Early trials suggest nicotine vaccines
are safe and well tolerated, but the duration of effect is unclear,
and immunological response varies across recipients.
Nicotine vaccines have not yet been
studied in phase 3 trials and the relative performance of different
vaccines, alone or in combination with existing therapeutic options,