NCT04408586

Anti-Obesity Phentermine-Topiramate Extended Release Pharmacotherapy vs Placebo Among Patients Using a Wearable Activity Tracker

Completed Phase 4 Results posted Last updated 22 June 2023

What this trial tests

Phase 4 trial testing Phentermine-Topiramate Extended Release in Obesity in 80 participants. Completed in 11 October 2022.

Timeline

3 June 2020

Primary endpoint
13 June 2022

11 October 2022

Quick facts

Lead sponsor	Mayo Clinic
Phase	Phase 4
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	double
Primary purpose	treatment
Enrollment	80
Start date	3 June 2020
Primary completion	13 June 2022
Estimated completion	11 October 2022
Sites	1 location across United States

Drugs / interventions tested

• Phentermine-Topiramate Extended Release
• Placebo
• Online support system

Conditions studied

• Obesity — all drugs for Obesity →

Sponsor

Mayo Clinic

Who can join

Adults 18 to 75, any sex, with Obesity. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Body Weight Change Primary · baseline, 3 months

Change in weight calculated in kilograms.

Group	Value	95% CI
Phentermine - Topiramate Extended Release Group	-10.80	-13.72 – -7.92
Placebo Group	-4.04	-7.05 – -1.04

Body Weight Change Secondary · baseline, 12 months

Change in weight calculated in kilograms.

Group	Value	95% CI
Phentermine - Topiramate Extended Release Group	-15.32	-18.65 – -12.00
Placebo Group	-5.85	-9.40 – -2.30

Change in Step Count Secondary · baseline,12 months

The change in the number of steps per day

Group	Value	95% CI
Phentermine - Topiramate Extended Release Group	1214	-192 – 2620
Placebo Group	2316	807 – 3824

Change in Calories Secondary · baseline, 12 months

The change in calories burned per day

Group	Value	95% CI
Phentermine - Topiramate Extended Release Group	-193	-356 – -30
Placebo Group	60	-127 – 247

Exercise Sessions Secondary · 12 months

The number of exercise sessions per week

Group	Value	95% CI
Phentermine - Topiramate Extended Release Group	2.3	± 1
Placebo Group	2.1	± 1

Tracker Usage Secondary · 12 months

The amount of time in minutes the tracker was used per week

Group	Value	95% CI
Phentermine - Topiramate Extended Release Group	90	± 15
Placebo Group	94	± 12

Change in SF-12 Physical Score (Health-related Quality Quality of Life) Secondary · baseline, 12 months

Quality of life SF12 physical score. The SF-12 is a well-validate measure of health-related quality of life; providing a physical and mental health component summary score. Min:0, Max: 100. Higher Score = Worse Outcome

Group	Value	95% CI
Phentermine - Topiramate Extended Release Group	1.99	-0.34 – 4.32
Placebo Group	0.57	-1.76 – 2.90

Change in SF-12 Mental Score (Health-related Quality Quality of Life) Secondary · baseline, 12 months

Quality of life SF12 mental score. The SF-12 is a well-validate measure of health-related quality of life; providing a physical and mental health component summary score. Min:0, Max: 100. Higher Score = Worse Outcome.

Group	Value	95% CI
Phentermine - Topiramate Extended Release Group	0.42	-1.66 – 2.50
Placebo Group	-1.48	-3.56 – 0.60

Adverse events — posted to ClinicalTrials.gov

Time frame: Adverse Events were collected from baseline to end of study, approximately 12 months for each subject. Reporting threshold: 0%. Adverse-event reports describe events observed during the trial — not all are caused by the drug.

Phentermine - Topiramate Extended Release Group

Serious: 0/42 (0%)

Deaths: 0/42

Placebo Group

Serious: 0/38 (0%)

Deaths: 0/38

Other adverse events (5 terms — click to expand)

Reaction	System	Phentermine - Topiramate E…	Placebo Group
Paresthesia	Nervous system disorders	—	—
Dry mouth	Gastrointestinal disorders	—	—
Dysgeusia	Nervous system disorders	—	—
Insomnia	Psychiatric disorders	—	—
Headache	Nervous system disorders	—	—

Data from ClinicalTrials.gov NCT04408586 adverse events section.

Sponsor's own description

Researchers are assessing the effects of weight loss medication vs a placebo among participants provided with a wearable activity tracker, digital wellness devices and lifestyle recommendations.

Publications & conference data

2 peer-reviewed publications reference this trial (live from Europe PMC):

1. Genetic and physiological insights into satiation variability predict responses to obesity treatment.
   Cifuentes L, Anazco D, O'Connor T, Hurtado MD, et al · · 2025 · cited 14× · PMID 40482646 · DOI 10.1016/j.cmet.2025.05.008
2. Addition of Phentermine-Topiramate to a Digitally Enhanced Lifestyle Intervention: A Double-Blind Randomized Clinical Trial.
   Campos A, Ghusn W, Cifuentes L, Sacoto D, et al · · 2026 · PMID 41562388 · DOI 10.1002/oby.70108