This is a molecular imaging research study designed to examine how much nicotine gets into the brain before and after vaccination with NicVAX, a nicotine vaccine developed by Nabi Biopharmaceuticals. NicVAX (Nicotine Conjugate Vaccine) is an investigational vaccine designed as an aid to smoking cessation and long-term abstinence, as well as an aid to prevent relapses of a treated smoker. In this project we want to understand the degree to which NicVAX administration changes how much nicotine enters the brain in smokers.
The purpose of the present study is to examine the occupancy of brain β2-containing nicotinic acetylcholine receptors (β2-nAChR) by nicotine both at baseline and following administration of a nicotine vaccine. The number of brain β2-nAChR and the amount of nicotine occupancy both before and after vaccination will be measured using the nicotinic agonist \[123I\]5-IA-85380 (\[123I\]5-IA) and single photon emission computed tomography (SPECT). \[123I\]5-IA will be administered using the bolus plus constant infusion paradigm to smokers abstinent for 4-9 days (time period necessary for nicotine and pharmacological active metabolites to clear from brain). Three baseline SPECT images will be obtained after equilibrium has been reached (\~6 hours into the \[123I\]5-IA infusion). Then, IV nicotine will be administered (0.5-1.5 mg/70 kg will be infused over 10 minutes). Following a series of 4 nicotine vaccine shots, the same procedure will be repeated for a second \[123I\]5-IA scan day. We hypothesize that occupancy of β2-nAChR will be significantly lower, and take longer to plateau, following nicotine vaccine administration.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
HEALTH_SERVICES_RESEARCH
Masking
NONE
Enrollment
14
1.0 mL of Nicotine Conjugate Vaccine(x4), I.M. at 3 week intervals between SPECT studies
up to 10 mCi of \[123I\]5-IA-85380, I.V. on each of two SPECT Scan days
0.5-1.5 mg of Nicotine bitartrate, I.V. on each of two SPECT Scan days
Veterans Association Connecticut Hospital System
West Haven, Connecticut, United States
Mean of the Average Nicotine Binding % at Scan 1 and Scan 2
nAchR levels from baseline and after immunization with 3'-AmNic-rEPA (NicVAX=vaccine) SPECT images obtained in healthy control smoking subjects at baseline and after immunization with 3'-AmNic-rEPA (NicVAX=vaccine). nAchR levels will be determined by radioligand uptake in SPECT images. Means were calculated for all subjects at scan 1 and scan 2.
Time frame: 3 months
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