A Phase 2 interventional study of Tirzepatide and Placebo in Smoking Cessation and Smoking Behaviors, sponsored by University of Southern California. Recruiting at 4 sites in United States. Open to participants aged 21 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-07-17.
Sponsored by University of Southern California · Phase 2, Interventional, and Treatment
This multi-site clinical trial will generate data on the efficacy of tirzepatide for smoking cessation and associated outcomes (e.g., post-cessation weight gain) in treatment-seeking people who smoke (PWS) with overweight or obesity. A sample of 300 treatment-seeking people who smoke with body mass index of 25 kg/m2 or greater will be recruited from four geographic sites (University of Southern California, Yale University, University of Chicago, and University of Colorado Anschutz Medical Campus) to participate in a parallel-arm, dose-escalating, placebo-controlled trial. Participants will attend weekly clinic visits to receive subcutaneous tirzepatide or placebo over 16 weeks (Visit Weeks 1-16), followed by follow-up visits at Week 17 and Week 27. Medication will be prescribed according to the standard dose titration schedule for the first 16 weeks of treatment (initial dose: 2.5mg/week; final dose: 10mg/week). All participants will also receive nicotine patches.
1,581 studies on the registry are indexed under Smoking Cessation; 198 are open to participants now.
This study's planned enrollment of 300 is above the median of 164 across 1,423 interventional studies indexed under Smoking Cessation.
Browse Smoking Cessation studies →University of Southern California is the lead sponsor of 791 studies on the registry; 136 are open to participants now.
Of its 70 completed or terminated interventional studies of FDA-regulated products, 32 (46%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HbA1c
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
DSM diagnostic criteria
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: Tirzepatide
Other: Placebo
Participants will receive tirzepatide (subcutaneous injection) at doses of 2.5mg for Weeks 1-4, 5mg for Weeks 5-8, 7.5mg for Weeks 9-12, and 10mg for Weeks 13-16
Participants will receive placebo (saline) injections for Weeks 1-16
7-day point prevalence abstinence
Biochemically verified abstinence from cigarette smoking
Time frame: From baseline through 16 weeks of treatment (final assessment at Week 17 visit) and at 6 months after the target quit date (assessed at Week 27 visit)
Cigarettes per day
Time frame: From baseline through 16 weeks of treatment (final assessment at Week 17 visit)
Weekly cigarette craving
Cigarette craving in the past week will be measured using the craving scale of the Wisconsin Smoking Withdrawal Scale, containing 4 items, each scored on a scale of 1-4. Items are summed to generate a score.
Time frame: Baseline through 16 weeks of treatment (final assessment at Week 17 visit)
Current cigarette craving
Current cigarette craving will be measured with the Questionnaire on Smoking Urges-Brief, a 10-item scale with items, each scored on a 1-7 scale. Items are summed to generate a total score.
Time frame: Baseline through 16 weeks of treatment (final assessment at Week 17 visit)
Smoking withdrawal
Withdrawal symptoms are measured with the Wisconsin Smoking Withdrawal Scale (WSWS). The WSWS includes 28 items, each rated on a scale of 0-4. Items are summed to calculate the scale scores.
Time frame: Baseline through 16 weeks of treatment (final assessment at Week 17 visit)
Body weight
Time frame: Treatment week 1 through treatment week 16 (final assessment at Week 17 visit)
Plan to share: Yes
Supporting information: Study protocol, Statistical analysis plan, Informed consent form
Time frame: The protocol and SAP will be made available at or before the completion of the study. Requests for IPD will be reviewed following publication of primary study results.
Access criteria: Data will be made available to researchers whose proposed purpose for accessing the data has been approved, and provided a data sharing agreement is in place.
No publications or documents are linked to this record.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
No contact was published for this record. The registry link below has the sponsor’s details.
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Studies of the drug tested here: Tirzepatide
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