Safety and Efficacy of Different Combinations of Zonisamide-CR Plus Bupropion-SR to Treat Uncomplicated Obesity

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00339014
Recruitment Status : Completed
First Posted : June 20, 2006
Last Update Posted : April 22, 2008
Information provided by:
Orexigen Therapeutics, Inc

Brief Summary:
The purpose of this study is to determine which of seven combinations of Zonisamide CR and Bupropion SR gives the best weight loss and is safe and well tolerated for the treatment of obesity not associated with the complications of obesity such as diabetes. In a previous study, the combination of zonisamide and bupropion SR was shown to be effective for weight loss compared to either zonisamide, bupropion SR alone or placebo. It is thought that by adjusting the doses of each drug, giving zonisamide in a controlled release (CR) form and increasing the doses more slowly, more weight loss and less side effects can be attained.

Condition or disease Intervention/treatment Phase
Obesity Drug: Zonisamide CR and Bupropion SR Other: Placebo Phase 2

Detailed Description:

Over the past few years, knowledge of the pathways and neural circuits that sense body energy stores has increased dramatically. In particular, it has been shown that the melanocortin system, a group of neuronal circuits in the arcuate nucleus of the hypothalamus, is the "final common pathway" for most energy state signals, and that melanocortin signaling is necessary for normal control of food intake and energy expenditure. Stimulation of POMC neurons by serotonergic and dopaminergic agents results in release of α-, β- and γ-MSH through the action of prohormone convertase-2 with a consequent decrease in appetite.A second counter-regulatory system that inhibits POMC activation is β-endorphin, which binds to a mu-opioid receptor (MOP-R) and acts as an auto-inhibitory "brake" on the activity of the melanocortin circuits. Bupropion is an approved antidepressant that blocks reuptake of serotonin and dopamine. This stimulates secretion of both α -MSH and β-endorphin. α -MSH binds to melanocortin receptors which in turn results in appetite suppression and increased energy expenditure. β-endorphin, however, binds to a mu-opioid receptor (MOP-R) and inhibits the activity of the melanocortin circuits. Zonisamide has multiple effects that may protect against seizures, including blockade of sodium channels, and reducing voltage dependent inward (T type) calcium currents, leading to neuronal stabilization. In addition to these actions, however, it is known to increase 5-hydroxytryptophan and dopamine levels, simultaneously stimulating α -MSH release while inhibiting AGRP release. Thus, the combination of bupropion and zonisamide stimulates the melanocortin system while blocking an important feedback inhibitory pathway.

The combination of zonisamide 400 mg/day and bupropion SR 300 mg/day has been shown to be more effective for weight loss than either monotherapy or placebo in subjects with uncomplicated obesity. The hypothesis for the current trial is that greater efficacy and improved tolerability can be achieved by adjusting the doses and titration of both bupropion SR and zonisamide, and by giving zonisamide in a controlled release (CR) formulation.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 611 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: A Dose Parallel, Randomized, Placebo-Controlled, Multicenter Study of the Safety and Efficacy of Multiple Regimens of the Combination of Zonisamide CR Plus Bupropion SR in the Treatment of Subjects With Uncomplicated Obesity
Study Start Date : May 2006
Actual Primary Completion Date : August 2007
Actual Study Completion Date : August 2007

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Active Comparator: Group 1
Zonisamide SR 120 mg/day plus Bupropion SR 280 mg/day
Drug: Zonisamide CR and Bupropion SR
Zonisamide SR and Bupropion SR

Active Comparator: Group 2
Zonisamide SR 120 mg/day plus Bupropion SR 360 mg/day
Drug: Zonisamide CR and Bupropion SR
Zonisamide SR and Bupropion SR

Active Comparator: Group 3
Zonisamide SR 240 mg/day plus Bupropion SR 280 mg/day
Drug: Zonisamide CR and Bupropion SR
Zonisamide SR and Bupropion SR

Active Comparator: Group 4
Zonisamide SR 240 mg/day plus Bupropion SR 360 mg/day
Drug: Zonisamide CR and Bupropion SR
Zonisamide SR and Bupropion SR

Active Comparator: Group 5
Zonisamide SR 360 mg/day plus Bupropion SR 280 mg/day
Drug: Zonisamide CR and Bupropion SR
Zonisamide SR and Bupropion SR

Active Comparator: Group 6
Zonisamide SR 360 mg/day plus Bupropion SR 360 mg/day
Drug: Zonisamide CR and Bupropion SR
Zonisamide SR and Bupropion SR

Placebo Comparator: Group 7 Other: Placebo
Identical placebo

Primary Outcome Measures :
  1. % change in total body weight as measured between baseline and week 24 (ITT-LOCF analysis) [ Time Frame: Baseline to week 24 ]

Secondary Outcome Measures :
  1. Absolute change in total body weight in kg. [ Time Frame: Baseline to week 24 ]
  2. Proportion of subjects achieving > 5% weight loss. [ Time Frame: Baseline to week 24 ]
  3. Proportion of subjects achieving > 10% weight loss. [ Time Frame: Baseline to week 24 ]
  4. Proportion of subjects achieving > 5% weight loss at week 24 who maintain response to week 48 [ Time Frame: Baseline to week 24 ]
  5. Change in measures of quality of life, sleep quality and sleep quantity [ Time Frame: Baseline to week 24 ]
  6. Change in fasting triglycerides level [ Time Frame: Baseline to week 24 ]
  7. Change in fasting blood glucose [ Time Frame: Baseline to week 24 ]
  8. Change in systolic and diastolic blood pressure [ Time Frame: Baseline to week 24 ]
  9. Change in HAMD-17 Maier subscale scores [ Time Frame: Baseline to week 24 ]
  10. Change in Brief Assessment of Cognition composite scores [ Time Frame: Baseline to week 24 ]

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Ages Eligible for Study:   18 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Have body mass index (BMI) of 30 to 43 kg/m2
  • Free from any other clinically significant illness or disease as determined by medical history and physical examination
  • Non-smoker and no use of tobacco or nicotine products for at least 6 months prior to screening
  • Normotensive (systolic <140 mm Hg; diastolic <90 mm Hg). Anti-hypertensive medications are allowed with the exception of adrenergic blockers, beta-blockers and clonidine. Medical regimen must be stable for at least 6 weeks
  • LDL cholesterol < 190 mg/dL and triglycerides < 400 mg/dL. Medications for treatment of dyslipidemia are allowed as long as medical regimen has been stable for at least 6 weeks
  • Negative serum pregnancy test in women with an intact uterus
  • Score < 15 for depression and score < 15 for anxiety on Hospital Anxiety and Depression Scale (HADS)
  • No clinically significant abnormality on ECG
  • Not on eExcluded concomitant medications
  • If female with intact uterus, be non-lactating, and agree to use effective contraception throughout the study period and for 30 days after discontinuation of study drugs.
  • Able to comply with all required study procedures and schedule
  • Able to use and have access to a touch tone telephone and to speak and read English

Exclusion Criteria:

  • Obesity of known endocrine or genetic origin
  • Serious medical condition
  • Serious psychiatric illness
  • Active suicidal ideation; score > 2 on the Mood Assessment questionnaire
  • A response to Bipolar Disorder questions indicating the presence of Bipolar Disorder
  • Type I diabetes mellitus or Type II diabetes mellitus requiring pharmacotherapy
  • History of alcohol or drug abuse, current or within 5 years
  • History of bulimia or anorexia nervosa
  • History of surgical intervention for obesity
  • History of seizure disorder or predisposition to seizures (e.g., history of cerebrovascular accident, significant head trauma, brain surgery, skull fracture, subdural hematoma, or alcohol withdrawal or febrile seizures)
  • History of hypersensitivity to sulfonamides ("sulfa"), bupropion, or zonisamide
  • History of nephrolithiasis (renal calculi)
  • History of treatment with bupropion SR (Wellbutrin, Zyban) or zonisamide (Zonegran) within 12 months
  • Use of drugs, herbs, or dietary supplements known to significantly affect body weight or participation in a weight loss management program within one month prior to baseline
  • Loss or gain of more than 4.0 kilos within 3 months
  • Women of child bearing potential not adhering to an acceptable form of contraception
  • Pregnant or breast-feeding women
  • Use of investigational drug, device or procedure within 30 days
  • Participation in any previous clinical trial conducted by Orexigen Therapeutics
  • Planned surgical procedure that can impact the conduct of the study
  • Any condition which in the opinion of the investigator makes the subject unsuitable for inclusion in this study

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00339014

United States, Alabama
SelfCenter, PC
Fairhope, Alabama, United States, 36532
United States, California
UCLA Center for Human Nutrition
Los Angeles, California, United States, 90095
Scripps Clinic Del Mar
San Diego, California, United States, 92130
United States, Colorado
Center for Human Nutrition University of Colorado Health Sciences Center
Denver, Colorado, United States, 80220
United States, District of Columbia
George Washington University Weight Management Program
Washington, District of Columbia, United States, 20037
United States, Georgia
CSRA Partners in Health, Inc
Augusta, Georgia, United States, 30909
United States, Illinois
Springfield Diabetes and Endocrine Center
Springfield, Illinois, United States, 62704
United States, Louisiana
Pennington Biomedical Research Center
Baton Rouge, Louisiana, United States, 70808
United States, Massachusetts
Nutrition and Weight Mangement Center Boston Medical Center
Boston, Massachusetts, United States, 02118
United States, Nevada
Center for Nutrition and Metabolic Diseases
Reno, Nevada, United States, 89557
United States, New York
Comprehensive Weight Control Program
New York, New York, United States, 10021
United States, North Carolina
Center for Nutrition and Preventive Medicine
Charlotte, North Carolina, United States, 28211
United States, South Carolina
MUSC Weight Mnagement Center
Charleston, South Carolina, United States, 29425
United States, Texas
The Cooper Institute
Dallas, Texas, United States, 75230
Baylor Endocrine Center
Dallas, Texas, United States, 75246
Sponsors and Collaborators
Orexigen Therapeutics, Inc
Principal Investigator: Frank Greenway, MD Pennington Biomedical Research Center

Responsible Party: Ronald Landbloom, MD, Orexigen Therapeutics, Inc Identifier: NCT00339014     History of Changes
Other Study ID Numbers: ZB 201
First Posted: June 20, 2006    Key Record Dates
Last Update Posted: April 22, 2008
Last Verified: April 2008

Additional relevant MeSH terms:
Nutrition Disorders
Body Weight
Signs and Symptoms
Antidepressive Agents, Second-Generation
Antidepressive Agents
Psychotropic Drugs
Dopamine Uptake Inhibitors
Neurotransmitter Uptake Inhibitors
Membrane Transport Modulators
Molecular Mechanisms of Pharmacological Action
Dopamine Agents
Neurotransmitter Agents
Physiological Effects of Drugs
Cytochrome P-450 CYP2D6 Inhibitors
Cytochrome P-450 Enzyme Inhibitors
Enzyme Inhibitors
Protective Agents