ObesityPhase 2NCT03525002
Dopamine Action on Metabolism in Relation to Genotype
A Phase 2 study testing Bromocriptine in people with Obesity, run by University Hospital Tuebingen at 3 sites in Germany.
Trial summary
Obesity is a widespread disease with increasing prevalence and associated with serious secondary complications. So far, the origin of the disease, regardless of an existing positive energy balance, is not fully understood. Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Obesity
- What is being tested?
- Bromocriptine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 120 participants
- Where
- 3 sitesGermany
- Study dates
- 3 May 2018to 14 Aug 2024
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Body mass index (BMI) between >30 kg/m².
- Understand and voluntarily sign an informed consent document prior to any study related assessments/procedures.
- Females of childbearing potential (FCBP) must agree to utilize a reliable form of contraception simultaneously or practice complete abstinence from heterosexual contact while participating in the study.
- Males must agree to use a latex condom during any heterosexual contact while participating in the study and to refrain from donating semen or sperm while participating in this study.
Who cannot join
- Women during pregnancy and lactation.
- History of hypersensitivity to the investigational medicinal product or to any drug with similar chemical structure or to any excipient present in the pharmaceutical form of the investigational medicinal products.
- Participation in other clinical trials or observation period of competing trials up to 30 days prior to this study.
- Diabetes mellitus
- Treatment with Methyldopa, levodopa, dopamine agonists, metoclopramid, domperidon, glycerol nitrate, griseofulvin, azol-antimycotic drugs, macrolide-antibiotics, octreotide, orlistat, tamoxifen, liraglutide
- Any relevant cardiovascular disease, e.g. myocardial infarction, acute coronary syndrome, unstable angina pectoris, Percutaneous transluminal coronary angioplasty (PTCA), heart failure (NYHA III-IV), stroke or transient ischemic attack (TIA)
Show all 26Show fewer
- Acute or chronic viral hepatitis or liver cirrhosis
- Impaired renal function, defined as estimated Glomerular Filtration Rate (eGFR) ≤ 60 ml/min (MDRD formula) as determined during screening.
- Medical history of cancer and/or treatment for cancer within the last 5 years.
- Claustrophobia
- Any other clinically significant major organ system disease at screening such as relevant gastrointestinal, neurologic, psychiatric, endocrine (i.e. pancreatic), hematologic, malignant, infection or other major systemic diseases making implementation of the protocol or interpretation of the study results difficult.
- Presence of any contraindication for the conduct of an MRI investigation, such as cardiac pacemakers, ferromagnetic haemostatic clips in the central nervous system, metallic splinters in the eye, ferromagnetic or electronically operated active devices like automatic cardioverter defibrillators, cochlear implants, insulin pumps and nerve stimulators, prosthetic heart valves etc.
- hyperthyroidism
- therapy refractary hypertension
- peripheral arterial disease
- Parkinson´s disease
- Known current presence or history of one of the following psychiatric diseases: depression, mania, anxiety and panic disorder, obsessive-compulsive disorder, schizophrenia, psychosis, addiction
- pituitary disease
- treatment with bromocriptine during 12 month before entering the trial
- dementia
- gastric or intestinal ulcer
- Persons with limited temperature sensation and / or elevated sensitivity to warming of the body
- Persons with a hearing disorder or a increased sensitivity for loud noises
- smoking
- Refusal to get informed of unexpected detected pathological findings
- Any other clinical condition that would jeopardize subjects' safety while participating in this clinical trial.
Trial locations and contacts
3 sites in 1 country.
Germany3 sites
University Hospital Cologne
Cologne
University Hospital Luebeck
Lübeck
University of Tuebingen, Department of Internal Medicine IV
Tübingen, 72076
About this study
Official title: Dopamine Action on Metabolism Depending on Genetic Heterogeneity - a Randomized, Placebo-controlled Double Blind Study
Obesity is a widespread disease with increasing prevalence and associated with serious secondary complications. So far, the origin of the disease, regardless of an existing positive energy balance, is not fully understood. In addition to environmental factors, the genetic background plays an important role in the pathogenesis of obesity. Of common genetic polymorphisms, variants in the fat mass and obesity associated gene (FTO) locus have the highest effect size on body weight. Animal and first clinical studies indicate that FTO variants interact with dopamine signaling in the brain, thus influencing the risk of overweight. In fact, preliminary results indicate that enhancing dopamine signaling with the dopamine agonist bromocriptine, depending on the FTO genotype, either induces weight loss or has a neutral effect on body weight.
The planned clinical trial serves to develop a genotype-specific and thus individualized therapy approach for obesity. The influence of dopamine agonist therapy on weight loss as a function of the FTO (rs8050136) genotype is to be tested.
Read more
Here, the greatest weight loss is expected to occur in subjects carrying the homozygous risk-allele (AA).
So far, there are only a few established conservative therapy forms of obesity, so that bariatric interventions with an increasing rate are necessary to achieve weight loss and thus a reduction in overall morbidity and mortality. Among the approved drug therapies for obesity, bromocriptine is commonly used. In addition, some interventions require injections. An early, conservative individualized, genotype-specific treatment with little side-effects would enable simple treatment of obesity.
Study design: 150 obese (BMI > 30) subjects (50 / study center) will be enrolled in the study. The subjects will be stratified according to their FTO genotype (rs8050136). Subjects will be randomized into placebo or bromocriptine treatment group. Treatment will last for 18 weeks and a follow-up will be performed 30 weeks after baseline.
- Conditions
- Obesity
- Being tested
- Bromocriptine, Placebo
- Medical subject headings
- Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
BromocriptineDrug
In each FTO genotype group participants will be randomly receive bromocriptine or placebo.
PlaceboOther
In each FTO genotype group participants will be randomly receive bromocriptine or placebo.
| Study group | Role | What they receive |
|---|---|---|
| FTO SNP rs8050136 (AA), Placebo | Placebo comparator | Participants with FTO SNP rs8050136 AA receiving matching Placebo Receives: Other: Placebo |
| FTO SNP rs8050136 (AA), Bromocriptine | Active comparator | Participants with FTO SNP rs8050136 AAreceiving Bromocriptine up to 5 mg Receives: Drug: Bromocriptine |
| FTO SNP rs8050136 (CA), Placebo | Placebo comparator | Participants with FTO SNP rs8050136 CA receiving matching Placebo Receives: Other: Placebo |
| FTO SNP rs8050136 (CA), Bromocriptine | Active comparator | Participants with FTO SNP rs8050136 CA receiving Bromocriptine up to 5 mg Receives: Drug: Bromocriptine |
| FTO SNP rs8050136 (CC), Placebo | Placebo comparator | Participants with FTO SNP rs8050136 CC receiving matching Placebo Receives: Other: Placebo |
| FTO SNP rs8050136 (CC), Bromocriptine | Active comparator | Participants with FTO SNP rs8050136 CC receiving Bromocriptine up to 5 mg Receives: Drug: Bromocriptine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Interaction between FTO genotype and treatment on change in body weight.
Interaction between FTO (single nucleotide peptide) SNP rs8050136 genotype and treatment (bromocriptine or placebo) on change in body weight.
Measured: 18 weeks
Secondary outcomes (11)
Effect of bromocriptine vs. placebo on body weight
Measured: 18 weeks
Effect of bromocriptine vs. placebo on dietary intake
Dietary intake will be monitored by food diaries
Measured: 18 weeks
Effect of bromocriptine vs. placebo on processing of food cues in the brain
Processing of food cues in the brain will be assessed by functional magnetic resonance imaging before and after treatment with bromocriptine or placebo
Measured: 18 weeks
Effect of bromocriptine vs. placebo on body fat distribution
Body fat distribution will be assessed by magnetic resonance imaging and magnetic resonance spectroscopy before and after treatment with bromocriptine or placebo
Measured: 18 weeks
Effect of bromocriptine vs. placebo on whole body insulin sensitivity
Whole body insulin sensitivity will be quantified from 5 point 75g oral glucose tolerance test before and after treatment with bromocriptine or placebo
Measured: 18 weeks
Effect of bromocriptine vs. placebo on insulin secretion
Insulin secretion will be quantified from 5 point 75g oral glucose tolerance test before and after treatment with bromocriptine or placebo
Measured: 18 weeks
Effect of bromocriptine vs. placebo on glucose tolerance
Glucose tolerance will be assessed by 75g oral glucose tolerance test before and after treatment with bromocriptine or placebo
Measured: 18 weeks
Effect of bromocriptine vs. placebo on brain insulin sensitivity
Brain insulin sensitivity will be assessed by functional magnetic resonance imaging combined with intranasal insulin administration before and after treatment with bromocriptine or placebo
Measured: 18 weeks
Effect of bromocriptine vs. placebo on resting energy expenditure
Resting energy expenditure will be assessed by indirect calorimetry before and after treatment with bromocriptine or placebo
Measured: 18 weeks
Effect of bromocriptine vs. placebo on physical activity
Physical activity will be monitored using an accelerometer
Measured: 18 weeks
Effect of bromocriptine vs. placebo on serum prolactin concentrations
Measured: 18 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 May 2018
- Study start3 May 2018
- Primary completion14 Aug 2024
- Study completion14 Aug 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ObesityStudies of the same condition, open and under way.
- More trials run by University Hospital TuebingenThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 120 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital Tuebingen
- Sponsor type
- University, hospital or other
- Collaborators
- University Hospital of Cologne, University Hospital Lübeck
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03525002
- Sponsor's protocol ID
- DopamineGenetics01
- Status last verified
- Nov 2025
- First submitted
- 2 May 2018
- Last updated
- 24 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 24 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Dopamine Action on Metabolism Depending on Genetic Heterogeneity - a Randomized, Placebo-controlled Double Blind Study
- ClinicalTrials.gov ID
- NCT03525002
- Acronym / sponsor ID
- DopamineGenetics01
- Conditions
- Obesity
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 120 participants (actual)
- Lead sponsor
- University Hospital TuebingenUniversity, hospital or other
- Collaborators
- University Hospital of Cologne, University Hospital Lübeck
- Study start
- 3 May 2018 (actual)
- Primary completion
- 14 Aug 2024 (actual)
- Study completion
- 14 Aug 2024 (actual)
- First posted
- 15 May 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Obesity is a widespread disease with increasing prevalence and associated with serious secondary complications. So far, the origin of the disease, regardless of an existing positive energy balance, is not fully understood. In addition to environmental factors, the genetic background plays an important role in the pathogenesis of obesity. Of common genetic polymorphisms, variants in the fat mass and obesity associated gene (FTO) locus have the highest effect size on body weight. Animal and first clinical studies indicate that FTO variants interact with dopamine signaling in the brain, thus influencing the risk of overweight. In fact, preliminary results indicate that enhancing dopamine signaling with the dopamine agonist bromocriptine, depending on the FTO genotype, either induces weight loss or has a neutral effect on body weight.
The planned clinical trial serves to develop a genotype-specific and thus individualized therapy approach for obesity. The influence of dopamine agonist therapy on weight loss as a function of the FTO (rs8050136) genotype is to be tested.
Here, the greatest weight loss is expected to occur in subjects carrying the homozygous risk-allele (AA).
So far, there are only a few established conservative therapy forms of obesity, so that bariatric interventions with an increasing rate are necessary to achieve weight loss and thus a reduction in overall morbidity and mortality. Among the approved drug therapies for obesity, bromocriptine is commonly used. In addition, some interventions require injections. An early, conservative individualized, genotype-specific treatment with little side-effects would enable simple treatment of obesity.
Study design: 150 obese (BMI > 30) subjects (50 / study center) will be enrolled in the study. The subjects will be stratified according to their FTO genotype (rs8050136). Subjects will be randomized into placebo or bromocriptine treatment group. Treatment will last for 18 weeks and a follow-up will be performed 30 weeks after baseline.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, investigator)
- Number of arms
- 6
| Arm | Type | Receives |
|---|---|---|
| FTO SNP rs8050136 (AA), Placebo | Placebo comparator | Other: PlaceboParticipants with FTO SNP rs8050136 AA receiving matching Placebo |
| FTO SNP rs8050136 (AA), Bromocriptine | Active comparator | Drug: BromocriptineParticipants with FTO SNP rs8050136 AAreceiving Bromocriptine up to 5 mg |
| FTO SNP rs8050136 (CA), Placebo | Placebo comparator | Other: PlaceboParticipants with FTO SNP rs8050136 CA receiving matching Placebo |
| FTO SNP rs8050136 (CA), Bromocriptine | Active comparator | Drug: BromocriptineParticipants with FTO SNP rs8050136 CA receiving Bromocriptine up to 5 mg |
| FTO SNP rs8050136 (CC), Placebo | Placebo comparator | Other: PlaceboParticipants with FTO SNP rs8050136 CC receiving matching Placebo |
| FTO SNP rs8050136 (CC), Bromocriptine | Active comparator | Drug: BromocriptineParticipants with FTO SNP rs8050136 CC receiving Bromocriptine up to 5 mg |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Body mass index (BMI) between >30 kg/m².
- Understand and voluntarily sign an informed consent document prior to any study related assessments/procedures.
- Females of childbearing potential (FCBP) must agree to utilize a reliable form of contraception simultaneously or practice complete abstinence from heterosexual contact while participating in the study.
- Males must agree to use a latex condom during any heterosexual contact while participating in the study and to refrain from donating semen or sperm while participating in this study.
Key exclusion criteria (26 listed)
- Women during pregnancy and lactation.
- History of hypersensitivity to the investigational medicinal product or to any drug with similar chemical structure or to any excipient present in the pharmaceutical form of the investigational medicinal products.
- Participation in other clinical trials or observation period of competing trials up to 30 days prior to this study.
- Diabetes mellitus
- Treatment with Methyldopa, levodopa, dopamine agonists, metoclopramid, domperidon, glycerol nitrate, griseofulvin, azol-antimycotic drugs, macrolide-antibiotics, octreotide, orlistat, tamoxifen, liraglutide
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| BromocriptineIn each FTO genotype group participants will be randomly receive bromocriptine or placebo. | Drug | FTO SNP rs8050136 (AA), Bromocriptine, FTO SNP rs8050136 (CA), Bromocriptine, FTO SNP rs8050136 (CC), Bromocriptine |
| PlaceboIn each FTO genotype group participants will be randomly receive bromocriptine or placebo. | Other | FTO SNP rs8050136 (AA), Placebo, FTO SNP rs8050136 (CA), Placebo, FTO SNP rs8050136 (CC), Placebo |
Primary outcome
Interaction between FTO genotype and treatment on change in body weight.
Time frame: 18 weeks
Interaction between FTO (single nucleotide peptide) SNP rs8050136 genotype and treatment (bromocriptine or placebo) on change in body weight.
11 secondary outcomes
Effect of bromocriptine vs. placebo on body weight
Time frame: 18 weeks
Effect of bromocriptine vs. placebo on dietary intake
Time frame: 18 weeks
Effect of bromocriptine vs. placebo on processing of food cues in the brain
Time frame: 18 weeks
Effect of bromocriptine vs. placebo on body fat distribution
Time frame: 18 weeks
Effect of bromocriptine vs. placebo on whole body insulin sensitivity
Time frame: 18 weeks
Effect of bromocriptine vs. placebo on insulin secretion
Time frame: 18 weeks
Effect of bromocriptine vs. placebo on glucose tolerance
Time frame: 18 weeks
Effect of bromocriptine vs. placebo on brain insulin sensitivity
Time frame: 18 weeks
Effect of bromocriptine vs. placebo on resting energy expenditure
Time frame: 18 weeks
Effect of bromocriptine vs. placebo on physical activity
Time frame: 18 weeks
Effect of bromocriptine vs. placebo on serum prolactin concentrations
Time frame: 18 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Nov 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Bromocriptine in people with Obesity, run by University Hospital Tuebingen at 3 sites in Germany.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 26 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 24 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in Germany. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Interaction between FTO genotype and treatment on change in body weight. (time frame: 18 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Nov 2025.