Actively Recruiting
Phentermine/Topiramate in Children, Adolescents, and Young Adults With Hypothalamic Obesity: a Pilot and Feasibility Study
Led by Seattle Children's Hospital · Updated on 2025-07-28
24
Participants Needed
2
Research Sites
13 weeks
Total Duration
On this page
Sponsors
S
Seattle Children's Hospital
Lead Sponsor
C
Children's Hospital of Philadelphia
Collaborating Sponsor
AI-Summary
What this Trial Is About
Researchers are evaluating the safety and effects of phentermine/topiramate (Ph/T) in children, adolescents, and young adults aged 6 to 28 years with hypothalamic obesity (HO), a serious condition often caused by hypothalamic brain tumors. This form of obesity is difficult to treat and linked to higher risks of metabolic problems and early death from heart-related diseases. Phentermine/topiramate is FDA-approved for common obesity but has not been tested in HO before. This Phase 2, double-blind, placebo-controlled trial aims to gather initial data on safety, dosing, and weight loss effects in this group. Participants will be randomly assigned to one of two groups: one receiving the active drug phentermine/topiramate with FDA-approved dose escalation until the highest tolerable dose is reached, and the other receiving placebo capsules that look identical. The treatment period lasts 28 weeks, followed by a one-week taper for those on the highest dose. The study is conducted at two centers and uses a double-blind design to compare changes between the active drug and placebo groups. During the trial, participants will attend a screening visit and five study visits at weeks 1, 3, 14, 16, and 28, with some visits possibly conducted remotely. There will be a remote contact after dose starts or increases to check tolerance and an additional follow-up at week 29 to assess withdrawal effects. Researchers will monitor adverse events, dosing tolerability, and changes in body mass index (BMI), fat mass, and hunger. Participants will be compensated for their time and travel. The total study duration for participants is about 29 weeks.
CONDITIONS
Brief Title
Efficacy and Safety of Phentermine/Topiramate in Youth With Hypothalamic Obesity
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Males and females aged 6 to 28 years inclusive
- History of rapid weight gain related to tumor onset or treatment as assessed by an endocrinologist
- Obesity defined as BMI greater than the 95th percentile for age/sex if under 18, or BMI over 30 kg/m2 if 18 years or older
- Recent hypothalamic injury shown by brain MRI with central review
- At least 6 months after definitive tumor therapy (surgery, chemotherapy, or radiation) with no major surgeries planned during study
- Stable on pituitary replacement and/or appetite-modulating medications for at least 2 months with minor dose adjustments allowed
- Post-menarchal females must use effective contraception unless hypogonadotropic hypogonadism is documented
- Ability to communicate well, comply with study requirements, and provide informed consent or assent with parental consent if under 18
You will not qualify if you...
- Contraindications to phentermine, topiramate, or Qsymia including history of glaucoma or hyperthyroidism
- History of kidney stones
- Current diagnosis of anorexia nervosa or bulimia nervosa
- History of metabolic acidosis or significant bone disease requiring medication
- Current or recent use of monoamine oxidase inhibitors
- Known hypersensitivity to sympathomimetic amines
- Significant cardiovascular conditions including abnormal blood pressure, arrhythmias, heart failure, prolonged QTc interval, or coronary artery disease
- Females who are pregnant, breastfeeding, or planning pregnancy during the trial
- Brittle diabetes insipidus requiring frequent hospitalizations
- Diabetes requiring insulin or secretagogues with HbA1c over 8.5% at screening
- Clinically significant hyperthyroidism
- History or current clinically significant hypokalemia
- Significant liver or kidney disease
- History of seizure in the past 12 months
- History of substance abuse, moderate or worse depression, psychiatric disorder, or suicidality
- History of abdominal surgery including gastric bypass
- Current use of supra-physiologic steroids
- Allergy or sensitivity to test agents including aspirin or FD&C Yellow No. 5
- Concurrent use of carbonic anhydrase inhibitors or non-potassium sparing diuretics
- Recent or planned new weight management medication, stimulant, or investigational medication within 2 months
- Cognitive impairment that precludes participation
- Other investigator-determined reasons making participation unsuitable
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - 28 weeks plus 1 week of tapering if highest dose reached
Participants will receive either the active drug Phentermine/Topiramate or a matching placebo, following an FDA-approved dose titration schedule to reach the highest tolerable dose while assessing safety and efficacy.
5 in-person or remote study visits at Weeks 1 (baseline), 3, 14, 16, and 28; 2 remote contacts one week after dose initiation or escalation and at week 29
Duration - 1 week after treatment ends
Participants are monitored for withdrawal effects and safety concerns after completing the treatment phase.
1 remote contact at Week 29, with in-person visit if safety concerns arise
Trial Site Locations
Total: 2 locations
1
The Children's Hospital of Philadelphia
Philadelphia, Pennsylvania, United States, 19104
Actively Recruiting
2
Seattle Children's
Seattle, Washington, United States, 98101
Actively Recruiting
Research Team
C
Christian L Roth, MD
S
Stephanie Purdy
How is the study designed?
Study Type
INTERVENTIONAL
Masking
QUADRUPLE
Allocation
RANDOMIZED
Model
PARALLEL
Primary Purpose
TREATMENT
Number of Arms
2
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