A randomized, active controlled clinical trial in which a total of 216 healthy smokers will be enrolled and followed over approximately 19 weeks.

The trial will evaluate the efficacy and safety of using X-22 as a smoking cessation aid.

Healthy smokers who plan to quit smoking will be screened for eligibility. Subjects will be randomized in a 1:1 ratio to 1 of the 2 treatment arms:

• Group 1: X-22 Cigarettes (very low nicotine)
• Group 2: Active Control Cigarettes The randomization will be stratified by gender. Efficacy will be assessed by analysis of cigarette consumption using self-report diaries and measurement of exhaled carbon monoxide (CO) and cotinine concentrations.

Safety will be assessed by evaluation of adverse events, physical examinations, clinical laboratory tests, and measurement of heart rate, blood pressure, and body weight at each study visit.

Inclusion Criteria:

• Subjects must meet all of the following inclusion criteria to be eligible for participation in this study.

  1. Subjects must be considered by the investigator to be in general good health and between 18 and 65 years of age, inclusive.
  2. Subjects must have a history of smoking at least 10 cigarettes per day for at least 1 year, with less than 3 months of abstinence during the past year, and a continuous smoking history for at least 3 months prior to study entry.
  3. Subjects must indicate that they plan to quit smoking within the next 3 months.
  4. Subjects must have a CO measurement of ≥ 10 ppm at screening and baseline (Visit 1 and Visit 2).
  5. Subjects must be willing and able to return for scheduled follow-up examinations for a total of 5 months.
  6. Female subjects must have been postmenopausal for the previous 6 months or be surgically sterile, or must have a negative pregnancy test and use one of the following acceptable methods of birth control for the duration of the study and for at least 3 months prior to screening:

• abstinence, meaning a total lack of sexual activity,

• oral contraceptives ("the pill"),

• contraceptive injections,

• intrauterine device,

• double-barrier method (diaphragm or condom plus spermicidal cream),

• contraceptive patch, hormonal implant, hormonal vaginal ring, or

• male partner sterilization at least 3 months prior to screening. 7. Subjects must sign and be given a copy of the written Informed Consent form. 8. Subjects must be able to read, understand and complete the questionnaires independently.

Exclusion Criteria:

• Subjects who meet any of the following exclusion criteria are not to be enrolled in this study.

  1. Subjects who have a household member who is already enrolled in this trial.
  2. Subjects who have attempted to quit smoking using one or more FDA-approved smoking cessation products (eg, nicotine replacement therapy [NRT] including nicotine gum, nicotine lozenges, nicotine patches, nicotine nasal spray, or nicotine inhaler; Zyban [bupropion]; or Chantix [varenicline]) for longer than 1 week in the past 3 months.
  3. Subjects who have been enrolled in another structured smoking cessation program (e.g., behavioral modification, hypnosis, acupuncture, or other alternative therapies) in the last 30 days.
  4. Subjects who have been in another smoking cessation trial in the past 6 months.
  5. Subjects who regularly use (greater than once per month) tobacco-based products other than cigarettes (eg, chew, snuff, snus, shisha, etc.).
  6. Subjects with a history of coronary artery disease, myocardial infarction, stroke, chronic obstructive pulmonary disease, or other significant pulmonary diseases. Controlled hypertensive subjects and mild asthmatics whose disease is controlled only with an as-needed inhaled beta agonist are acceptable.
  7. Subjects with a history of cancer within the past 60 months other than basal cell carcinoma.
  8. Subjects with a history of thromboembolic disease or taking warfin or any other anticoagulant, or anti-platelet drug such as clopidogrel (Plavix®) or pentoxifylline (Trental®). Low dose aspirin therapy is acceptable.
  9. Subjects with screening laboratory abnormalities that are considered by the investigator to be clinically significant.
  10. Subjects with a body mass index (BMI) >35.
  11. Subjects with poorly controlled diabetes or insulin-dependent diabetes.
  12. Subjects with other known serious pathophysiology or topical or systemic disorders of any kind that would confound the results of the study.
  13. Subjects with screening ECG abnormalities that are considered by the investigator to be clinically significant.
  14. Subjects who have used any illegal drug in the past 3 months.
  15. Subjects who have a positive urine drug screening result.
  16. Subjects who are pregnant or lactating, or who plan to become pregnant during the course of the study.
  17. Subjects participating in any other clinical trial of an investigational drug or device during the time of this clinical investigation or within 30 days prior to Screening visit.
  18. Subjects taking anti-depressants, anti-psychotics, clonidine, or any of the classes of drugs listed in the RapidCHECK® 12 Panel in the last 60 days (see Section 12.1.1).
  19. Subjects with systolic blood pressure over 140 mmHg and/or diastolic blood pressure over 90 mmHg.
  20. Subjects consuming an average of 3 or more drinks of alcohol per day.
  21. Subjects consuming greater than an average of 2 packs of cigarettes per day.