Trial Information

Enhancing Tobacco Use Treatment for African American Light Smokers

OBJECTIVES:

Primary

- To evaluate the efficacy of bupropion hydrochloride and health education counseling vs
placebo and health education counseling for smoking cessation among African Americans
who are light smokers.

Secondary

- To characterize CYP2A6 activity in African Americans who are light smokers by
evaluating phenotype (3'hydroxycotinine/cotinine ratio [3HC/COT]) and CYP2A6 genotype.

- To evaluate the relationship between CYP2A6 activity and smoking cessation outcomes.

- To evaluate CYP2A6 genetic polymorphisms associated with nicotine and cotinine
metabolism in African Americans who are light smokers.

- To measure baseline cotinine and metabolite levels to evaluate the nicotine metabolism
phenotype of 3HC/COT.

- To evaluate the relationship between nicotine metabolism phenotype of 3HC/COT and
smoking cessation outcomes.

- To evaluate CYP2A6 genotype as a predictor of smoking cessation outcomes.

Tertiary

- To characterize CYP2B6 activity in African Americans who are light smokers by
evaluating phenotype and CYP2B6 genotype.

- To evaluate the relationship between CYP2B6 activity and smoking cessation outcomes.

- To measure steady state bupropion hydrochloride and metabolite levels to identify a
bupropion metabolism phenotype.

- To evaluate the relationship between bupropion hydrochloride metabolism phenotype and
smoking cessation outcomes.

- To evaluate the relationship between CYP2B6 genetic polymorphisms (genotype) and blood
levels of bupropion hydrochloride and active metabolites (phenotype).

- To determine the effects of CYP2B6 genotype as predictors of smoking cessation
outcomes.

OUTLINE: Participants are randomized to one of two arms.

- Arm I: Participants receive oral bupropion hydrochloride once or twice daily in weeks
0-6. Participants also undergo 6 sessions of health education counseling conducted in
person during clinic visits in weeks 0, 3, and 7 and via telephone in weeks 1, 5, and
16. The health education counseling sessions include providing information about the
risks of continued smoking and the benefits of quitting, developing a quit plan,
outlining a concrete quit day preparation plan, discussing strategies for successful
quitting, building social support, reducing stress, recognizing and managing withdrawal
and craving, overcoming barriers to abstinence, and using medication for smoking
cessation. Participants receive Kick It at Swope: Stop Smoking Guide, a
culturally-sensitive smoking cessation guide, to review with their study counselor
during the first counseling session.

- Arm II: Participants receive an oral placebo once or twice daily in weeks 0-6.
Participants also undergo health education counseling as in arm I.

Participants complete baseline questionnaires about demographics, smoking history, and
psychometrics, including the following: racial identity, depressive symptoms, alcohol use,
stress, smoking consequences, social support, environmental influences of smoking, adherence
to study medication, nicotine withdrawal, craving, and mood.

Participants undergo serum sample collection in weeks 0 and 3. To standardize the time since
the last cigarette, participants are asked to smoke one cigarette prior to serum sample
collection in week 0. Samples are analyzed for nicotine metabolism phenotype and bupropion
hydrochloride metabolism phenotype by liquid chromatography and mass spectrometry and CYP2A6
and CYP2B6 genotype by polymerase chain reaction and polymorphism analysis. Participants who
self-report abstinence also undergo saliva sample collection in weeks 7 and 26 to measure
cotinine levels to verify smoking status.

After completion of study intervention, participants are followed at 6 months.