NCT06899178 · Icahn School of Medicine at Mount Sinai
Atomoxetine in Melanocortin Obesity Syndrome
(MCOS)
What this study is about
This is a phase 2 randomly assigned compared against an inactive treatment crossover trial to determine the safety and effectiveness of atomoxetine for treating obesity caused by loss-of-function variants in the melanocortin-4 receptor (MC4R), the most common cause of genetic obesity disorders.
View original scientific description
This is a phase 2 randomized placebo-controlled crossover trial to determine the safety and efficacy of atomoxetine for treating obesity caused by loss-of-function variants in the melanocortin-4 receptor (MC4R), the most common cause of genetic obesity disorders. Atomoxetine was selected for this pilot trial because it has been shown to increase brain-derived neurotrophic factor (BDNF) within the central nervous system and in peripheral circulation.
Interventions
DRUG
Atomoxetine
Initial dose 40 mg, day 7 dose 60 mg, day 14 dose 80 mg, day 21 dose 100 mg (target dose)
DRUG
Placebo
Matching placebo oral capsule
Primary outcome measures
Body Mass Index (BMI)
Time frame: 16 weeks
BMI will be calculated as kg/sq m. The sex appropriate CDC growth chart will be used to calculate BMI as a percent of the 95th percentile (BMI95). For patients \>20 years, the 20-year-old percentiles will be used.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Age 6 years and above
- Documented MC4R variant classified as pathogenic, likely pathogenic, or variant of uncertain significance per ACMG criteria. If testing was done in a research lab, it will be confirmed by a CLIA-approved lab prior to randomization.
- Obesity defined as BMI ≥30 kg/m2 in adults or ≥95th percentile for age and sex in children
Exclusion criteria
- Use of atomoxetine, viloxazine (another selective norepinephrine-reuptake inhibitor), methylphenidate, amphetamine, dextroamphetamine, lisdexamfetamine, phentermine, or any other stimulant medication in the past 30 days. If on other ADHD medications, such as guanfacine and clonidine, must be on a stable dose for \>3 months.
- Weight loss \>5% in the past 3 months.
- Initiation of new weight loss program, including diet or medications. If on weight loss medications, must be on a stable dose for \>3 months.
- Inability to swallow capsules.
- History of hypersensitivity to atomoxetine.
- Narrow angle
Where
- New York, New York
- Columbus, Ohio
- Nashville, Tennessee
Collaborators
Vanderbilt University Medical Center, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Aug 7, 2026 · Source of record for eligibility and locations