In smokers who are motivated to stop smoking, treatment with lorcaserin compared with placebo will provide greater abstinence as measured by the last 4 weeks of treatment (Weeks 9-12). The target quit date was Day 15.

Inclusion Criteria:

1. Males or females aged 18-65 years, inclusive

2. ≥10 cigarettes per day with no period of abstinence longer than 3 months in the past year and who are motivated to quit smoking

3. Able to give signed informed consent

4. Eligible female patients will be:

   1. non-pregnant
   2. non-lactating
   3. agree to use an acceptable method of effective contraception during the study

5. Eligible male patients agree to use contraception when sexually active with a female partner who is not using an acceptable method of birth control

6. Body weight of ≥50 kg (110 pounds), inclusive

7. Considered to be in stable health in the opinion of the investigator

Exclusion Criteria:

Patients who meet any of the following criteria will be excluded from the study.

1. Prior or current use of lorcaserin HCl
2. Prior participation in any study of a nicotine vaccination
3. Use of other therapies for smoking cessation is not allowed within 3 months of screening through study exit
4. Use of tobacco products other than cigarettes
5. Prior use of fenfluramine or dexfenfluramine
6. Serious or unstable medical condition or clinically significant new illness within the 6 months prior to screening
7. Previous participation in any clinical study within 6 weeks prior to the screening visit
8. History of severe allergies, severe drug or excipient allergy or hypersensitivity
9. History of significant cardiovascular condition
10. History of other significant medical conditions
11. Significant risk of suicide
12. Anticipated use of any agents that are associated with valvulopathy and/or pulmonary hypertension
13. Positive test result for human immunodeficiency virus (HIV), hepatitis B, or hepatitis C
14. Recent history of alcohol or drug/solvent abuse
15. Concurrent participation in the study by more than one member of the same household
16. Not suitable to participate in the study in the opinion of the investigator