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Smoking habits,
a vaccine and varenicline
Safety, immunogenicity and some early signs of efficacy
for the nicotine vaccine, TA-NIC
Campbell Bunce
Powerpoint
Presentation
Abstract
Sixty smokers were recruited into a double-blind, randomised,
placebo-controlled, dose escalation study to assess the
safety and immunogenicity of the nicotine vaccine, TA-NIC,
and identify the optimal dose for future efficacy trials.
They were divided into three cohorts of 20 subjects randomised
4:1 active vaccine to placebo per group. Each group received
a different dose of TA-NIC corresponding to 50mcg, 250mcg
and 1000mcg per injection given at weeks 0, 2, 4, 6, 8
and 12. The interim results (20 weeks) of this Phase 1
study demonstrated that the vaccine was safe and well
tolerated with a small number of severe adverse injection
site reactions at the highest dose level.
The anti-nicotine antibody response to the vaccine was
dose dependent with a marked improvement in the rate and
magnitude of the response compared to a previous study.
Based on safety and immunogenicity data at the interim
stage, 250 mcg was identified as the optimal dose. In
addition, there was a clear reduction across all actively
vaccinated groups versus placebo in the numbers of those
who self-reported a reduction in smoking pleasure or spontaneously
quit - for example, at week six 43% of subjects receiving
TA-NIC compared to only 9% receiving the placebo, reported
reduced pleasure when smoking or had quit. The 12 month
follow-up is now complete and initial analysis has confirmed
the selection of the 250mcg dose for future studies. Also,
12 month self reported quit rates were substantially greater
amongst those receiving TA-NIC than those receiving placebo:
8% of placebo subjects reported being abstinent at 12
months compared to 19% and 38% in the two groups receiving
the higher doses of TA-NIC.
Campbell Bunce
Xenova Ltd, Cambridge
campbell.bunce@xenova.com
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