RecruitingPhase 2

Phentermine's Impact on Treatment in Teens

United States240 participantsStarted 2026-06-03

Plain-language summary

PhITT is a Phase IIb, multicenter, randomized, double-blind, placebo-controlled clinical trial evaluating the efficacy and safety of phentermine (16 mg daily) in adolescents aged 12 to \<18 years with obesity. Conducted across approximately 10 sites within the IDeA States Pediatric Clinical Trials Network (ISPCTN), the study aims to enroll up to 240 participants and then randomize up to 198 who meet eligibility criteria, randomized in a 2:1 ratio to phentermine or placebo over a 52-week treatment period, followed by a 2-week withdrawal assessment.

Who can participate

Age range

12 Years – 17 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria\* include, but are not limited to: * Age ≥ 12 years and \< 18 years at time of consent; * Tanner Staging ≥ 2 at the time of screening; * Obesity (BMI ≥ 95th age- and sex-specific CDC percentile or BMI ≥ 30 kg/m2); * Biological females must agree to use adequate contraception, defined as double barrier methods, stable hormonal contraception plus single barrier method, tubal ligation, or abstinence. Exclusion criteria\* include, but are not limited to: * Contraindications to phentermine in adults such as: * A history of cardiovascular disease (e.g., coronary artery disease, stroke, clinically significant congenital heart disease, clinically significant cardiac arrhythmias, and congestive heart failure); * History of glaucoma; * Current or recent (within 14 days of screening) use of a monoamine oxidase (MAO) inhibitor; * Any previous history of drug dependency or current use of an illicit substance (positive urine drug screen); * Current pregnancy or breastfeeding; * Plans to become pregnant within the study duration; * Known hypersensitivity to sympathomimetic amines; * Current nicotine use or nicotine cessation within 3 months of screening; * Stage 2 hypertension (or greater) or taking any medication to treat hypertension; * Current type 1 or type 2 diabetes mellitus or taking any medication to treat diabetes or prediabetes; * Current or recent (within 3 months of screening) use of prescribed weight loss medication(s)/medically prescribed d…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Percent Change in BMI from Baseline at Week 52

Timeframe: 52 weeks

Trial details

NCT IDNCT07282340

SponsorRussell McCulloh, MD

Sponsor typeNETWORK

Study typeINTERVENTIONAL

Primary completion2028-01

Contact for this trial

Aubrey VanStory

402-559-4815 aubrey.vanstory@unmc.edu

View on ClinicalTrials.gov More Childhood Obesity trials