Multi-system Atrophy - Parkinsonian TypePhase 1/2CARBIDOHNCT06831500
Feasibility Study Assessing the Effect of Carbidopa/Levodopa Ratio on Orthostatic Hypotension in Multiple System Atrophy - Parkinsonian Type and Parkinson Disease.
A Phase 1/2 study testing Administration of Carbidopa/levodopa in people with Multi-system Atrophy - Parkinsonian Type and Orthostatic Hypotension, Dysautonomic, run by Julien Bally at 2 sites in Switzerland.
Trial summary
This study is aimed at patients with multi-system atrophy - parkinsonian type (P-MSA) or Parkinson's disease (PD) receiving dopaminergic drugs and suffering from orthostatic hypotension (OH). Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- Multi-system Atrophy - Parkinsonian Type, Orthostatic Hypotension, Dysautonomic, Parkinson Disease
- What is being tested?
- Administration of Carbidopa/levodopa
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 36 participants
- Where
- 2 sitesSwitzerland
- Study dates
- 18 Jul 2025to Nov 2026
- Phase
- Phase 1/2
- Are there results?
- Not yet: the study is under way
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 Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Informed consent form signed.
- Patient over 18 years and under 80 years of age.
- Patient with Multiple System Atrophy- Parkinsonian type (MSA-P) (confirmed by diagnostic criteria for clinically established and clinically probable multiple system atrophy (11); OR Patient with Parkinson Disease (PD) (12) presenting OH symptoms (getting at least one point at the 3 questions - n° 14, 15 and 16 - of the SCOPA-AUT scale that address orthostatic hypotension symptoms).
- Patient currently receiving Dopamine-Replacement Therapy (i.e. Levodopa combined with Carbidopa or Benserazide).
Who cannot join
- Patient unable to stand an overnight (at least 12 hours) withdrawal of their immediate-release DRT (last extended-, delayed-, or controlled-release dosage must be taken minimum 24 hours prior to the test).
- Patient with known congestive heart failure, grades C and D, NYHA III and IV.
- Patient with dementia (i.e. major cognitive impairment) associated to MSA-P or PD,
- Patient with mild cognitive impairment, and unable to provide or understand informed consent, i.e. who does not have full capacity for discernment.
- Current participation to other clinical trials.
- Pregnant or lactating woman or willing to become pregnant.
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Switzerland2 sites, 2 recruiting
- Recruiting
Centre Hospitalier Universitaire Vaudois (CHUV)
Lausanne, Canton of Vaud, 1005
Matthieu Robitaille, Doctor, +15819826059, matthieu.robitaille@chuv.ch
Julien Bally, Doctor, +41079 556 78 19, julien.bally@chuv.ch
- Recruiting
Centre Hospitalier Universitaire Vaudois
Lausanne, Canton of Vaud, 1012
Julien Bally, Dr. PD MER, +41 79 556 78 19, julien.bally@chuv.ch
About this study
Official title: A Monocentric, Randomized, Double-blind Study to Assess the Feasibility of Conducting a Full-scale Randomized Controlled Trial (RCT) Assessing the Effect of Carbidopa/Levodopa Ratio on Orthostatic Hypotension (OH) in Multiple System Atrophy - Parkinsonian Type (MSA-P) and Parkinson Disease (PD) Patients (CARBIDOH)
This study is aimed at patients with multi-system atrophy - parkinsonian type (P-MSA) or Parkinson's disease (PD) receiving dopaminergic drugs and suffering from orthostatic hypotension (OH).
OH is a drop in blood pressure when standing, which can lead to symptoms of dizziness, lightheadedness, a black veil in front of the eyes and, when severe, can lead to fainting. HO is one of the symptoms present in AMS-P and PD.
Read more
The standard treatment for parkinsonian symptoms of slowness and stiffness is the administration of antiparkinsonian drugs containing dopamine. These dopaminergic drugs always contain 1) levodopa (which is the precursor of dopamine) and 2) an enzyme inhibitor, which may be either benserazide (in the case of Madopar® and its generics) or carbidopa (in the case of Sinemet® or Stalevo® and their generics) and whose role is to potentiate the effect of levodopa.
It has long been known that dopaminergic drugs aggravate HO. Through various mechanisms, this worsening of HO is linked as much to levodopa as to the enzyme inhibitor with which it is combined. However, investigators do not know the respective effects of these two molecules on HO.
In this study, investigators examine how the ratio of Carbidopa to levodopa affects HO in the various assays of the dopaminergic drug under study.
- Conditions
- Multi-system Atrophy - Parkinsonian Type, Orthostatic Hypotension, Dysautonomic, Parkinson Disease
- Being tested
- Administration of Carbidopa/levodopa
- Keywords
- CARBIDOH
- Medical subject headings
- Shy-Drager Syndrome, Parkinson Disease
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Administration of Carbidopa/levodopaDrug
Participants will perform beat-by-beat orthostatic tests (Schellong tests) before and after intake of single doses of carbidopa:levodopa combinations at 3 different ratios
| Study group | Role | What they receive |
|---|---|---|
| Ratio 1:10 i.e. 20 mg Carbidopa / 200 mg Levodopa | Active comparator | This Carbidopa / Levodopa IMP ratio will be administered as a single dose, orally, at visit 1 or 2 or 3 (random order). Receives: Drug: Administration of Carbidopa/levodopa |
| Ratio 1:4 i.e. 50 mg Carbidopa / 200 mg Levodopa | Active comparator | This Carbidopa / Levodopa IMP ratio will be administered as a single dose, orally, at visit 1 or 2 or 3 (random order). Receives: Drug: Administration of Carbidopa/levodopa |
| Ratio 1:2 i.e. 100 mg Carbidopa / 200 mg Levodopa | Experimental | This Carbidopa / Levodopa IMP ratio will be administered as a single dose, orally, at visit 1 or 2 or 3 (random order). Receives: Drug: Administration of Carbidopa/levodopa |
What is being measured
The primary outcome is the main question the study is designed to answer.
Feasibility of future large-scale double-blind randomized controlled trial (RCT)
The primary objective is to investigate the feasibility of conducting a future large-scale double-blind randomized controlled trial (RCT) assessing the effect on orthostatic hypotension (OH) of different dosages of Carbidopa (20, 50 or 100 mg), for a constant Levodopa dose (200 mg) through:
- Recruitment rate: Mean number of patients informed per month during the recruitment period, % of patients wiling to participate to the study among the informed patients, % of patients eligible among the informed patients
- Adherence rate:% of patients completing the study intervention period among randomized patients
- Retention rate:% of patients showing up at the last follow-up visit among patients who have completed the study intervention period, % of drop-outs among randomized patients at last follow-up visit
- Data completion rate of the therapeutic effect measures: % of patients with analysable OH data at week 1, 2 and 3.
Measured: From enrollment to the end of study at 5 weeks.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Feb 2025
- Study start18 Jul 2025
- Primary completionNov 2026 (estimated)
- Study completionNov 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Multi-system Atrophy - Parkinsonian TypeStudies of the same condition, open and under way.
- 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 1/2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- It's a monocentric, randomized, double-blind study to assess the feasibility of conducting a full-scale randomized controlled trial (RCT). As a cross over model study, each patient will receive the 3 ratios of the investigational drug (corresponding to the 3 arms) in a random order.
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 36 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Julien Bally
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Julien Bally, University of Lausanne Hospitals
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06831500
- Sponsor's protocol ID
- 2024-02568
- Acronym
- CARBIDOH
- Status last verified
- Jul 2025
- First submitted
- 12 Feb 2025
- Last updated
- 29 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 29 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Monocentric, Randomized, Double-blind Study to Assess the Feasibility of Conducting a Full-scale Randomized Controlled Trial (RCT) Assessing the Effect of Carbidopa/Levodopa Ratio on Orthostatic Hypotension (OH) in Multiple System Atrophy - Parkinsonian Type (MSA-P) and Parkinson Disease (PD) Patients (CARBIDOH)
- ClinicalTrials.gov ID
- NCT06831500
- Acronym / sponsor ID
- CARBIDOH / 2024-02568
- Conditions
- Multi-system Atrophy - Parkinsonian Type, Orthostatic Hypotension, Dysautonomic, Parkinson Disease
- Keywords
- CARBIDOH
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 36 participants (estimated)
- Lead sponsor
- Julien BallyUniversity, hospital or other
- Study start
- 18 Jul 2025 (actual)
- Primary completion
- Nov 2026 (estimated)
- Study completion
- Nov 2026 (estimated)
- First posted
- 18 Feb 2025 (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.
This study is aimed at patients with multi-system atrophy - parkinsonian type (P-MSA) or Parkinson's disease (PD) receiving dopaminergic drugs and suffering from orthostatic hypotension (OH).
OH is a drop in blood pressure when standing, which can lead to symptoms of dizziness, lightheadedness, a black veil in front of the eyes and, when severe, can lead to fainting. HO is one of the symptoms present in AMS-P and PD.
The standard treatment for parkinsonian symptoms of slowness and stiffness is the administration of antiparkinsonian drugs containing dopamine. These dopaminergic drugs always contain 1) levodopa (which is the precursor of dopamine) and 2) an enzyme inhibitor, which may be either benserazide (in the case of Madopar® and its generics) or carbidopa (in the case of Sinemet® or Stalevo® and their generics) and whose role is to potentiate the effect of levodopa.
It has long been known that dopaminergic drugs aggravate HO. Through various mechanisms, this worsening of HO is linked as much to levodopa as to the enzyme inhibitor with which it is combined. However, investigators do not know the respective effects of these two molecules on HO.
In this study, investigators examine how the ratio of Carbidopa to levodopa affects HO in the various assays of the dopaminergic drug under study.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
- Model description
- It's a monocentric, randomized, double-blind study to assess the feasibility of conducting a full-scale randomized controlled trial (RCT). As a cross over model study, each patient will receive the 3 ratios of the investigational drug (corresponding to the 3 arms) in a random order.
| Arm | Type | Receives |
|---|---|---|
| Ratio 1:10 i.e. 20 mg Carbidopa / 200 mg Levodopa | Active comparator | Drug: Administration of Carbidopa/levodopaThis Carbidopa / Levodopa IMP ratio will be administered as a single dose, orally, at visit 1 or 2 or 3 (random order). |
| Ratio 1:4 i.e. 50 mg Carbidopa / 200 mg Levodopa | Active comparator | Drug: Administration of Carbidopa/levodopaThis Carbidopa / Levodopa IMP ratio will be administered as a single dose, orally, at visit 1 or 2 or 3 (random order). |
| Ratio 1:2 i.e. 100 mg Carbidopa / 200 mg Levodopa | Experimental | Drug: Administration of Carbidopa/levodopaThis Carbidopa / Levodopa IMP ratio will be administered as a single dose, orally, at visit 1 or 2 or 3 (random order). |
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (4 listed)
- Informed consent form signed.
- Patient over 18 years and under 80 years of age.
- Patient with Multiple System Atrophy- Parkinsonian type (MSA-P) (confirmed by diagnostic criteria for clinically established and clinically probable multiple system atrophy (11); OR Patient with Parkinson Disease (PD) (12) presenting OH symptoms (getting at least one point at the 3 questions - n° 14, 15 and 16 - of the SCOPA-AUT scale that address orthostatic hypotension symptoms).
- Patient currently receiving Dopamine-Replacement Therapy (i.e. Levodopa combined with Carbidopa or Benserazide).
Key exclusion criteria (6 listed)
- Patient unable to stand an overnight (at least 12 hours) withdrawal of their immediate-release DRT (last extended-, delayed-, or controlled-release dosage must be taken minimum 24 hours prior to the test).
- Patient with known congestive heart failure, grades C and D, NYHA III and IV.
- Patient with dementia (i.e. major cognitive impairment) associated to MSA-P or PD,
- Patient with mild cognitive impairment, and unable to provide or understand informed consent, i.e. who does not have full capacity for discernment.
- Current participation to other clinical trials.
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 |
|---|---|---|
| Administration of Carbidopa/levodopaParticipants will perform beat-by-beat orthostatic tests (Schellong tests) before and after intake of single doses of carbidopa:levodopa combinations at 3 different ratios | Drug | Ratio 1:10 i.e. 20 mg Carbidopa / 200 mg Levodopa, Ratio 1:2 i.e. 100 mg Carbidopa / 200 mg Levodopa, Ratio 1:4 i.e. 50 mg Carbidopa / 200 mg Levodopa |
Primary outcome
Feasibility of future large-scale double-blind randomized controlled trial (RCT)
Time frame: From enrollment to the end of study at 5 weeks.
The primary objective is to investigate the feasibility of conducting a future large-scale double-blind randomized controlled trial (RCT) assessing the effect on orthostatic hypotension (OH) of different dosages of Carbidopa (20, 50 or 100 mg), for a constant Levodopa dose (200 mg) through: * Recruitment rate: Mean number of patients informed per month during the recruitment period, % of patients wiling to participate to the study among the informed patients, % of patients eligible among the informed patients * Adherence rate:% of patients completing the study intervention period among randomized patients * Retention rate:% of patients showing up at the last follow-up visit among patients who have completed the study intervention period, % of drop-outs among randomized patients at last follow-up visit * Data completion rate of the therapeutic effect measures: % of patients with analysable OH data at week 1, 2 and 3.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Jan 2026.
- Individual participant dataSharing planned: Yes
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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.
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing Administration of Carbidopa/levodopa in people with Multi-system Atrophy - Parkinsonian Type and Orthostatic Hypotension, Dysautonomic, run by Julien Bally at 2 sites in Switzerland.
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 6 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: looking for participants now, as of the sponsor's last update on 29 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Switzerland. 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. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Julien BALLY, Dr PD-MER (+41 79 556 78 19, julien.bally@chuv.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Feasibility of future large-scale double-blind randomized controlled trial (RCT) (time frame: From enrollment to the end of study at 5 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 29 Jan 2026.