Weight Loss in Obese Adults Using Sibutramine versus a Combination of Sibutramine and Topiramate

Weight loss in adults with obesity using Sibutramine versus combination of Sibutramine and Topiramate

Status

Active, not recruiting

Phases

Phase 4

Study type

Interventional

Source

REBEC

Registry ID

RBR-106bgs3c

Enrollment

154

Registered

2025-06-30

Start date

2024-11-05

Completion date

Unknown

Last updated

2026-09-14

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Obesity Nutritional and Metabolic Disease

Interventions

This is a randomized superiority clinical trial stratified by gender through RedCap, double-blind, controlled in two arms in a 1:1 ratio. The control group consists of 77 participants with overweight

Eligibility

Age

18 Years to 64 Years

Inclusion criteria

Inclusion criteria: Participants aged between 18 and 64 years; both sexes; with a Body Mass Index - BMI greater than or equal to 30 kg/m² or a BMI greater than or equal to 27 with risk factors

Exclusion criteria

Exclusion criteria: Diagnosis of type 2 diabetes mellitus with one risk factor for cardiovascular disease; history of heart disease such as coronary artery disease, heart failure, tachycardia, peripheral arterial obstructive disease, arrhythmia, cerebrovascular disease, or uncontrolled hypertension (BP maior que 145 por 90 mmHg); renal or hepatic insufficiency; bulimia or anorexia; use of other antiobesity medications in the past 3 months; personal or family history of nephrolithiasis; pregnant or breastfeeding

Design outcomes

Primary

Measure	Time frame
Expected outcome 1: To evaluate whether the combination of sibutramine plus topiramate is superior to sibutramine plus placebo in reducing body weight from baseline to week 48 of treatment. The outcome will be assessed using body weight measured on a calibrated digital scale, without shoes, and the percentage weight reduction will be calculated using the following formula: [(baseline weight - weight at week 48) / baseline weight] × 100. A between-group difference of 3.5 percentage points, with a common standard deviation of 7%, was anticipated. The mean percentage weight reduction in each group, the estimated between-group difference, the 95% confidence interval, and the p-value will be analyzed. ;Observed outcome 1: A greater percentage reduction in body weight was observed in the sibutramine plus topiramate group compared with the sibutramine plus placebo group after 48 weeks. The outcome was assessed using body weight measured on a calibrated digital scale and the percentage reduction from baseline. Mean weight reduction was 10.71% (SD 7.78; n=57) in the sibutramine plus topiramate group and 6.71% (SD 5.06; n=45) in the sibutramine plus placebo group. The estimated between-group difference was 4.15 percentage points (95% CI 1.51 to 6.80; p<0.001), confirming the superiority of the topiramate combination.	—

Measure

Time frame

Expected outcome 1: To evaluate whether the combination of sibutramine plus topiramate is superior to sibutramine plus placebo in reducing body weight from baseline to week 48 of treatment. The outcome will be assessed using body weight measured on a calibrated digital scale, without shoes, and the percentage weight reduction will be calculated using the following formula: [(baseline weight - weight at week 48) / baseline weight] × 100. A between-group difference of 3.5 percentage points, with a common standard deviation of 7%, was anticipated. The mean percentage weight reduction in each group, the estimated between-group difference, the 95% confidence interval, and the p-value will be analyzed. ;Observed outcome 1: A greater percentage reduction in body weight was observed in the sibutramine plus topiramate group compared with the sibutramine plus placebo group after 48 weeks. The outcome was assessed using body weight measured on a calibrated digital scale and the percentage reduction from baseline. Mean weight reduction was 10.71% (SD 7.78; n=57) in the sibutramine plus topiramate group and 6.71% (SD 5.06; n=45) in the sibutramine plus placebo group. The estimated between-group difference was 4.15 percentage points (95% CI 1.51 to 6.80; p<0.001), confirming the superiority of the topiramate combination.

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Secondary

Measure	Time frame
Expected outcome 2: To evaluate the percentage reduction in body weight from baseline to week 24 of treatment, comparing the sibutramine plus topiramate and sibutramine plus placebo groups. The outcome will be assessed using body weight measured on a calibrated digital scale and calculated using the following formula: [(baseline weight - weight at week 24) / baseline weight] × 100. The mean percentage weight reduction in each group, the estimated between-group difference, the 95% confidence interval, and the p-value will be analyzed. ;Observed outcome 2: A greater percentage reduction in body weight was observed in the sibutramine plus topiramate group after 24 weeks. The outcome was assessed using body weight measured on a calibrated digital scale and the percentage reduction from baseline. Mean weight reduction was 9.57% (SD 5.09; n=64) in the sibutramine plus topiramate group and 6.86% (SD 3.70; n=62) in the sibutramine plus placebo group. The estimated between-group difference was 2.52 percentage points (95% CI 0.02 to 5.02; p=0.046). ;Expected outcome 3: To evaluate the proportions of participants achieving weight reductions of at least 5%, 10%, and 15% from baseline after 48 weeks, comparing the treatment groups. The outcome will be assessed using body weight measured on a calibrated digital scale and by classifying participants according to their percentage weight reduction from baseline. The number and proportion of participants achieving each prespecified threshold and the comparisons between groups will be analyzed. ;Observed outcome 3: Greater proportions of participants achieved weight reductions of at least 10% and 15% in the sibutramine plus topiramate group. The outcome was assessed by classifying participants with body weight data available at week 48 according to the prespecified thresholds. Weight reduction =5% was achieved by 73.7% of participants in the sibutramine plus topiramate group and 64.4% in the sibutramine plus placebo group (p=0.314)	—

Measure

Time frame

Expected outcome 2: To evaluate the percentage reduction in body weight from baseline to week 24 of treatment, comparing the sibutramine plus topiramate and sibutramine plus placebo groups. The outcome will be assessed using body weight measured on a calibrated digital scale and calculated using the following formula: [(baseline weight - weight at week 24) / baseline weight] × 100. The mean percentage weight reduction in each group, the estimated between-group difference, the 95% confidence interval, and the p-value will be analyzed. ;Observed outcome 2: A greater percentage reduction in body weight was observed in the sibutramine plus topiramate group after 24 weeks. The outcome was assessed using body weight measured on a calibrated digital scale and the percentage reduction from baseline. Mean weight reduction was 9.57% (SD 5.09; n=64) in the sibutramine plus topiramate group and 6.86% (SD 3.70; n=62) in the sibutramine plus placebo group. The estimated between-group difference was 2.52 percentage points (95% CI 0.02 to 5.02; p=0.046). ;Expected outcome 3: To evaluate the proportions of participants achieving weight reductions of at least 5%, 10%, and 15% from baseline after 48 weeks, comparing the treatment groups. The outcome will be assessed using body weight measured on a calibrated digital scale and by classifying participants according to their percentage weight reduction from baseline. The number and proportion of participants achieving each prespecified threshold and the comparisons between groups will be analyzed. ;Observed outcome 3: Greater proportions of participants achieved weight reductions of at least 10% and 15% in the sibutramine plus topiramate group. The outcome was assessed by classifying participants with body weight data available at week 48 according to the prespecified thresholds. Weight reduction =5% was achieved by 73.7% of participants in the sibutramine plus topiramate group and 64.4% in the sibutramine plus placebo group (p=0.314)

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Countries

Contacts

Public ContactHeloisa Yamamoto

Santa Casa de Misericórdia de São Paulo

draheloisa_yamamoto@hotmail.com+55(11)2176-7000

Outcome results

None listed

Source: REBEC (via WHO ICTRP) · Data processed: Sep 19, 2026