Adjunct Phentermine + Topiramate After Bariatric Surgery in 12-24 Year Olds

NCT04095104 | Completed Phase 2 Results DMC FDA Drug

• 2 other identifiers: 18-27935P30DK048520-24
• Study Type: interventional
• Target: 13
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this pilot study is to establish the feasibility and initial efficacy of the combination of phentermine and topiramate for adolescents and young adults who require additional risk reduction after bariatric surgery. This study will use a randomized, placebo-controlled, double-blinded design to evaluate an adjunctive 12-week intervention of phentermine + topiramate + standard of care vs. placebos + standard of care 6 months after bariatric surgery, among 12 to 24 year olds who don't achieve expected weight loss or who remain severely obese (n=10 total).

Conditions

Obesity, Morbid; Bariatric Surgery; Adolescent; Young Adult; Drug Therapy

Keywords

Pilot; Feasibility; Initial Efficacy; Randomized Controlled Trial

Outcome Measures

Primary Outcomes (4)

• Enrollment Rate

  (Number enrolled divided by number eligible) x 100

  6 months

• Dropout Rate

  Number who do not complete the study divided by number enrolled

  24 months

• Number of Participants Adherent to Study Drugs

  Presence of amphetamine in the urine at any study visit

  12 weeks

• Frequency of Adverse Events

  Unique adverse events documented prior to unblinding. Adverse events were elicited using a standardized checklist during study phone calls and in-person study visits, laboratory monitoring, review of systems, vitals, physical exam, and mood/suicidality assessment using validated instruments at every study visit.

  24 months

Secondary Outcomes (24)

• Percent BMI Change

  Baseline and 12 weeks

• Percent Weight Change

  Baseline and 12 weeks

• Change in BMI Percent of the 95th%Ile

  Baseline and 12 weeks

• Change in Heart Rate

  Baseline and 12 weeks

• Change in Systolic Blood Pressure

  Baseline and 12 weeks

Study Arms (2)

Phentermine & Topiramate

EXPERIMENTAL

Phentermine- Formulation: 8mg scored tablet, Dosage/Frequency/Duration: 4mg x 7d then 8mg x 7d then 12mg x 7d then 16mg x 63d, taken once every morning \+ Immediate release topiramate- Formulation: 25mg tablet, Dosage/Frequency/Duration: 25mg x 7d then 50mg x 7d then 75mg x 7d then 100mg x 63d then 50mg x 7 days then 25mg x 7d, taken once every morning \+ Standard of Care (multidisciplinary postoperative bariatric surgery clinic visits)

Drug: Phentermine; Drug: Immediate Release Topiramate

Placebo Drugs

PLACEBO COMPARATOR

Placebo Phentermine- Formulation: 8mg scored tablet, Dosage/Frequency/Duration: 4mg x 7d then 8mg x 7d then 12mg x 7d then 16mg x 63d, taken once every morning \+ Placebo Immediate release topiramate- Formulation: 25mg tablet, Dosage/Frequency/Duration: 25mg x 7d then 50mg x 7d then 75mg x 7d then 100mg x 63d then 50mg x 7 days then 25mg x 7d, taken once every morning \+ Standard of Care (multidisciplinary postoperative bariatric surgery clinic visits)

Drug: Placebo for Phentermine; Drug: Placebo for Immediate Release Topiramate

Interventions

Phentermine DRUG

Phentermine tablet

Also known as: Lomaira, Adipex-P, C045TQL4WP, 2-methyl-1-phenylpropan-2-amine

Phentermine & Topiramate

Immediate Release Topiramate DRUG

Topiramate tablet

Also known as: Topamax, 0H73WJJ391, [(3aS,5aR,8aR,8bS)-2,2,7,7-tetramethyl-5,5a,8a,8b-tetrahydrodi[1,3]dioxolo[4,5-a:5',3'-d]pyran-3a-yl]methyl sulfamate

Phentermine & Topiramate

Placebo for Phentermine DRUG

Compounded tablet to mimic phentermine 8mg tablet

Placebo Drugs

Placebo for Immediate Release Topiramate DRUG

Compounded tablet to mimic immediate release topiramate 25mg tablet

Placebo Drugs

Eligibility Criteria

• Age: 12 Years - 24 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Status post sleeve gastrectomy or roux-en-y gastric bypass
• At 6 months after bariatric surgery, has not achieved \>= 26% decrease in weight from preoperative weight (within 1 week of surgery) OR remains severely obese (\>=120% of 95th%ile or BMI \>=35kg/m2 for 12-17yo; BMI \>=35kg/m2 for 18-24yo)

You may not qualify if:

• Absolute contraindication to phentermine or topiramate (i.e. phentermine:
• history of coronary artery disease, stroke, arrhythmia, congestive heart failure, uncontrolled hypertension), hypersensitivity to sympathomimetic amines, current or recent (within 14 days) use of monoamine oxidase inhibitors, glaucoma, or hyperthyroidism; topiramate: hypersensitivity to topiramate, history of nephrolithiasis)
• Concomitant use of phenytoin, carbamazepine, or carbonic anhydrase inhibitors (e.g. zonisamide, acetazolamide, or dichlorphenamide)
• Use of anti-obesity medication within 6 months of screening
• Initiation of a new medication associated with weight loss or gain within 30 days of screening
• Type 2 diabetes mellitus
• Hypothalamic obesity
• Unmanaged (e.g. without medications and/or psychotherapy) clinically significant (determined by a mental health professional using diagnostic instruments and/or clinical interview) depression or anxiety
• History of any suicidal behavior within 30 days of screening or any suicidal ideation with either some intent to act or with intent and a specific plan within 30 days of screening
• History of schizophrenia
• Severe hepatic impairment (ALT \>10x upper limit of normal or known synthetic liver dysfunction)
• Moderate or severe renal impairment (GFR \<30mL/min/1.73m2)
• Dosage change to hypertension, dyslipidemia, depression, or anxiety medication \<4 weeks prior to study enrollment
• Contraception started \<7 days prior to study enrollment
• Current pregnancy/plans to become pregnant within 16 weeks from study drug start date

Sponsors & Collaborators

• University of Colorado, Denver: lead
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): collaborator
• University of Colorado- Clinical and Translational Sciences Institute: collaborator
• University of Colorado- Nutrition Obesity Research Center: collaborator

Study Sites (1)

Children's Hospital Colorado

Aurora, Colorado, 80045, United States

Location

MeSH Terms

Conditions

Obesity, Morbid

Interventions

Phentermine; Topiramate

Condition Hierarchy (Ancestors)

Obesity; Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Amphetamines; Phenethylamines; Ethylamines; Amines; Organic Chemicals; Fructose; Hexoses; Monosaccharides; Sugars; Carbohydrates; Ketoses

Results Point of Contact

• Title: Jaime Moore, MD MPH
• Organization: University of Colorado School of Medicine

jaime.moore@cuanschutz.edu

303-724-8419

Study Officials

• Jaime M Moore, MD, MPH

  University of Colorado School of Medicine

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: At baseline, each participant will be randomized 1:1 to either 12 weeks of phentermine, topiramate and standard of care or 12 weeks of phentermine placebo, topiramate placebo, and standard of care. This randomization will be blinded to the participant, investigator, care providers, and outcomes assessor for the duration of the study.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Two-arm parallel assignment where the experimental arm will receive active drugs + standard of care and the control arm will receive placebo drugs + standard of care.

Study Record Dates

• First Submitted: September 17, 2019
• First Posted: September 19, 2019
• Study Start: January 15, 2020
• Primary Completion: January 25, 2022
• Study Completion: January 25, 2022
• Last Updated: May 23, 2025
• Results First Posted: May 23, 2025

Record last verified: 2025-05

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF
• Time Frame: Data requests can be submitted starting 9 months after article publication and the data will be made accessible for up to 24 months. Extensions will be considered on a case-by-case basis.
• Access Criteria: Access to trial IPD can be requested by qualified researchers engaging in independent scientific research, and will be provided following review and approval of a research proposal and Statistical Analysis Plan and execution of a Data Sharing Agreement. For more information or to submit a request, please contact clinicalresearchsupportcenter@ucdenver.edu

Locations

US (1)