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NCT Number: NCT07602699

Multi-Site Trial of Tirzepatide for Smoking Cessation

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.

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Key information

Age range

21 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Keck School of Medicine, University of Southern California, Los Angeles, California, United States

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 21-65 years
  • Body mass index ≥ 25kg/m2 at the baseline screening
  • Reporting ≥10 cigarettes per day, on average, for the past 6 months and > 2 year duration of smoking
  • Interest in making a long-term cessation attempt within the next 30-60 days
  • Willingness to receive study medication and standard-of-care smoking cessation supports (nicotine replacement therapy and a smoking cessation app)
  • Ability to adhere to weekly visits and study procedures over the study period (i.e., no plans to move or travel for extended periods)
  • Exhaled CO of >5ppm at baseline
  • Use of an acceptable birth control method for female participants*
  • Ability to read and communicate in English

Exclusion criteria

  • BMI < 25 kg/m2 at screening
  • History of diabetes, diabetes-attributable medical conditions, or HbA1c ≥6.5% at baseline
  • Recent (past 90 days) active suicidal ideation or lifetime history of suicide attempt
  • Current treatment for psychotic disorders or mood disorders with psychotic features (e.g., schizophrenia, schizoaffective disorder, depression with psychotic features), current treatment for bipolar disorder (with or without psychotic features), or current secondary psychosis due to substance use or another medical condition
  • Meeting DSM-5 criteria for a current (past 12 months) substance use disorder other than tobacco use disorder, mild or moderate cannabis use disorder, or mild or moderate alcohol use disorder.
  • Recent (past 30 day) self-report of illicit drug use (excluding cannabis) or non-prescribed opioids; or positive urine screen for illicit drugs. A positive screen for opioids will be allowed if the participant is prescribed an opioid replacement therapy medication and can provide documentation.
  • Past 30-day initiation of psychiatric medications (e.g., SSRIs) or changes to medication dose
  • Treatment with tirzepatide or another GLP-1RA medication in the prior 6 months
  • Current (past month) treatment with other weight loss, diabetes, or smoking cessation medications (varenicline or bupropion; excluding nicotine replacement products)
  • Severe GI disease (e.g., gastroparesis, ulcerative colitis).
  • History of gastric bypass surgery or other surgeries of the stomach
  • Any health condition or treatment/medication that would preclude the use of tirzepatide or NRT, in the opinion of the study physician, including severe cardiovascular disease
  • History of chronic pancreatitis or acute pancreatitis in the last 6 months
  • Currently nursing, pregnant, or anticipating pregnancy
  • History of diabetic retinopathy, proliferative retinopathy, or maculopathy
  • Elevated serum lipase, amylase, bilirubin, or ALP, ALT, or AST (>5x upper limit of normal range)
  • History of malignant neoplasms in the last 5 years, except non-melanoma skin cancer
  • Inability to attend weekly clinic visits as scheduled (i.e., based on travel or work schedule)
  • Currently enrolled in another clinical study involving an investigational product
  • Currently living in the same household as someone taking a GLP-1 medication, or living with a current or former participant in the present trial
  • Planned surgical procedures requiring anesthesia during the planned study medication period
  • Personal or family history of medullary thyroid cancer
  • Personal or family history of multiple endocrine neoplasia syndrome type 2 (MEN 2)
  • Treatment with other weight loss (e.g., phentermine), or FDA-approved, non-NRT smoking cessation therapies (varenicline, bupropion) or FDA-approved AUD medications (naltrexone, acamprosate, disulfiram) or off-label AUD medications (e.g., topiramate) in the past 90 days
  • Any health condition or treatment/medication that would preclude use of tirzepatide or NRT, in the opinion of the site physicians including thyroid enlargement.

Treatment and study plan

Tirzepatide

Drug

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

Placebo

Other

Participants will receive placebo (saline) injections for Weeks 1-16

Primary outcomes

  1. 7-day point prevalence abstinence

    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)

    Biochemically verified abstinence from cigarette smoking

Secondary outcomes

  1. Cigarettes per day

    Time frame: From baseline through 16 weeks of treatment (final assessment at Week 17 visit)

  2. Weekly cigarette craving

    Time frame: Baseline through 16 weeks of treatment (final assessment at Week 17 visit)

    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.

Other outcomes

  1. Current cigarette craving

    Time frame: Baseline through 16 weeks of treatment (final assessment at Week 17 visit)

    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.

  2. Smoking withdrawal

    Time frame: Baseline through 16 weeks of treatment (final assessment at Week 17 visit)

    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.

  3. Body weight

    Time frame: Treatment week 1 through treatment week 16 (final assessment at Week 17 visit)

Sponsors and collaborators

Lead sponsor

University of Southern California

Other

Collaborators

  • National Institute on Drug Abuse (NIDA)

Registry information

Official study title

A Multi-Site Trial of Tirzepatide for Smoking Cessation

Important dates

Study start
2026
Primary completion
2028
Study completion
2028
First posted
May 22, 2026
Registry last updated
Jul 17, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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