PARKINSON DISEASE (Disorder)Phase 3TOX PARKNCT07822893
Effect of Botulinum Toxin on Resting Tremor of the Refractory Upper Limb in Parkinsonians
A Phase 3 study of PARKINSON DISEASE (Disorder), run by University Hospital, Toulouse at 2 sites in France.
Trial summary
Tremor is one of the most common symptoms in Parkinson Disease (PD), affecting almost 60% of patients. There is currently no specific treatment for tremor in PD, and 30% of patients develop drug-resistant tremor, making its management more complex. Read more about this study
- Who is it for?
- Ages 40 to 80 years
- Conditions the study is for
- PARKINSON DISEASE (Disorder)
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 39 participants
- Where
- 2 sitesFrance
- Study dates
- Dec 2026to Dec 2029
- Phase
- Phase 3
- 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 40 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients with PD defined according to UKPDSBB criteria;
- Men and women aged between 40 and 80 years;
- Patients with troublesome rest tremor assessed by the CGI-S scale ≥ 3 and persistent despite the initiation of ≥ two anti-parkinsonian treatments (levodopa, dopaminergic agonist, anticholinergic), which defines drug-resistant parkinsonian tremor;
- Patients naïve to botulinum toxin treatment;
- Patients whose antiparkinsonian treatment has been stable for at least 4 weeks prior to inclusion and for the duration of the study;
- Person affiliated with or beneficiary of a social security scheme;
- Free, informed, and written consent signed by the participant and the investigator (no later than the day of inclusion and before any examination required by the research).
Who cannot join
- Patients with tremors related to a pathology other than PD;
- Patients with atypical parkinsonian syndrome;
- Patients treated with drugs which have the adverse effect of causing the appearance or aggravation of tremors: lithium, sodium valproate, levetiracetam, benzodiazepines, corticosteroids, thyroid hormones, ciclosporin, alcohol, tricyclic antidepressants, theophillyne, terbutaline, antipsychotics (excluding clozapine) ;
- Patients with hypersensitivity to the active substance or to one of the excipients (human albumin, lactulose);
- patients with atrophy of the target muscle
- patients with a urinary tract infection at the time of treatment if the patient suffers from urinary incontinence due to neurological detrusor overactivity
Show all 11Show fewer
- patients with a history of swallowing or respiratory disorders;
- patients with marked clinical or subclinical neuromuscular transmission deficits (e.g., myasthenia gravis);
- patients with fixed contractures Pregnant or breastfeeding women;
- Women of childbearing age without effective contraception;
- Patients under legal guardianship, tutorship, or curatorship.
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
France2 sites
Nîmes University Hospital
Nîmes, 30 029
Giovanni Castelnovo, MD, 04 66 68 32 63 ext. +33, giovanni.castelnovo@chu-nimes.fr
Giovanni Castelnovo, MD
Pierre Paul Riquet Hospital - Toulouse University Hospital
Toulouse, 31 059
Clémence Leung, MD, 05 61 77 61 76 ext. +33, leung.c@chu-toulouse.fr
Clémence Leung, MD
About this study
Official title: Evaluation of the Effect of Botulinum Toxin on Resting Tremor of the Refractory Upper Limb in Parkinsonians, Cross-over Study, Double Blind and Placebo-controlled
Tremor is one of the most common symptoms in Parkinson Disease (PD), affecting almost 60% of patients. There is currently no specific treatment for tremor in PD, and 30% of patients develop drug-resistant tremor, making its management more complex. Botulinum toxin (BT) is widely used in neurology, but few studies have been carried out on the effect of BT in parkinsonian tremor without consensus on its management in parkinsonian patients. In this study, the investigators therefore propose to evaluate the effect of BT injected using precision medicine in the treatment of refractory resting tremor in patients with PD, compared with placebo injection.
Read the detailed description
Parkinson's disease (PD) is the second most common neurodegenerative disease. Tremor is one of the most common symptoms, affecting almost 60% of patients. It has a considerable impact on their quality of life, causing psychosocial stress in over 25% of patients. There is currently no specific treatment for tremor in PD, and 30% of patients develop drug-resistant tremor, making its management more complex. Botulinum toxin (BT) has been approved in France in 1994 and is widely used in neurology. To date, few studies have been carried out on the effect of BT in parkinsonian tremor: most have been open-label and have mixed parkinsonian patients and patients with essential tremor. Therefore, there is no consensus on the management of tremor in patients with PD. Nevertheless, there is a real need for treatment of refractory tremor, particularly in elderly patients, patients who cannot tolerate high doses of medication or patients who are ineligible for neurostimulation. In this study, the investigators therefore propose to evaluate the effect of BT injected using precision medicine in the treatment of refractory resting tremor in parkinsonian patients, compared with placebo injection. The investigators hypothesize that BT treatment improves parkinsonian tremor in a clinically relevant way compared to placebo injection using an optimized and personalized injection technique (doses of toxin and muscles injected). The drug will be injected intramuscularly into the muscles identified as responsible for the tremor, by an investigator specialising in injections. PD patients with resistant tremor will be included and followed up in this study for one year. BT or placebo will be injected at 6 months apart in all patients thanks to the cross over study design.
- Conditions
- PARKINSON DISEASE (Disorder)
- Being tested
- Injection of Dysport then placebo, Injection of placebo then Dysport
- Keywords
- parkinson disease, resistant tremor, botulinic toxin, precision medicine
- Medical subject headings
- Parkinson Disease
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Injection of Dysport then placeboDrug
Both treatments, first DYSPORT 500UI for 6 months then placebo, also for 6 months, will be administered intramuscularly using the same schedule and procedures thus allowing the blind to be maintained. The two injections will be carried at 6 months apart: the drug will be injected intramuscularly, into the muscles identified as responsible for the tremor, by an investigator specialized in carrying out injections. The doses injected will depend on the severity of the tremor and the number of muscles injected, which is conditioned by the tremor phenotype.
Injection of placebo then DysportDrug
Both treatments, first placebo for 6 months then DYSPORT 500UI, also for 6 months, will be administered intramuscularly using the same schedule and procedures thus allowing the blind to be maintained. The two injections will be carried at 6 months apart: the drug will be injected intramuscularly, into the muscles identified as responsible for the tremor, by an investigator specialized in carrying out injections. The doses injected will depend on the severity of the tremor and the number of muscles injected, which is conditioned by the tremor phenotype.
| Study group | Role | What they receive |
|---|---|---|
| Botulinum toxin followed by placebo arm | Experimental | In this cross-over study, the patient will be his or her own control. The patient will receive both treatments at 6 months apart: DYSPORT followed by the placebo (the order of injections has been randomly assigned). Receives: Drug: Injection of Dysport then placebo |
| Placebo followed by botulinum toxin arm | Experimental | In this cross-over study, the patient will be his or her own control. The patient will receive both treatments at 6 months apart: placebo followed by DYSPORT (the order of injections has been randomly assigned). Receives: Drug: Injection of placebo then Dysport |
What is being measured
The primary outcome is the main question the study is designed to answer.
The effect of botulinum toxin on the resting tremor of the upper limb refractory to treatments
It will be assessed by the PGI-C (Patient Global Impression-Change) score completed by the patient six weeks after injection and compared between treatments.
Measured: 7,5 months
Secondary outcomes (17)
The effect of botulinum toxin on the resting tremor: evolution evaluated by the investigator
It will be assessed by the CGI-C (Clinician Global Impression-Change) investigator-level change score, six weeks after injection.
Measured: 7,5 months
The effect of botulinum toxin on the resting tremor: severity evaluated by the investigator
It will be assessed by the delta of severity scores at the CGI-S (Clinician Global Impression-Severity) investigator level between injection and six weeks post-injection.
Measured: 7,5 months
The effect of botulinum toxin on the resting tremor: amplitude evaluated by the investigator
It will be assessed by the delta of the item score 3.17 (amplitude) at the MDS-UPDRS III investigator level between injection and six weeks post-injection.
Measured: 7,5 months
The effect of botulinum toxin on the resting tremor: patient-assessed severity
It will be assessed by the delta of severity scores at the patient scale PGI-S (Patient Global Impression-Severity) between injection and six weeks post-injection.
Measured: 7,5 months
The effect of botulinum toxin on the postural tremor: evolution evaluated by the investigator
It will be assessed by the change score at the CGI-C investigator scale, at six weeks post-injection.
Measured: 7,5 months
The effect of botulinum toxin on the postural tremor: severity evaluated by the investigator
It will be assessed by the delta of severity scores at the CGI-S investigator level between injection and six weeks post-injection.
Measured: 7,5 months
The effect of botulinum toxin on the postural tremor: amplitude evaluated by the investigator
It will be assessed by the delta of item 3.21 (amplitude) at the MDS-UPDRS III investigator level between injection and six weeks post-injection.
Measured: 7,5 months
The effect of botulinum toxin on the postural tremor: patient-assessed change
It will be assessed by the PGI-C scale score completed by the patient six weeks after injection and compared between groups.
Measured: 7,5 months
The effect of botulinum toxin on the postural tremor: patient-assessed severity
It will be assessed by the delta of severity scores on the PGI-S (Patient Global Impression-Severity) scale completed by the patient between the injection and six weeks post-injection.
Measured: 7,5 months
The effect of botulinum toxin on the Parkinsonian tremor (at rest and postural): duration
It will be assessed by the proportion of time the patient has a tremor, measured using an actimeter for 7 days prior to the assessment visit.
Measured: 12 months
The effect of botulinum toxin on the Parkinsonian tremor (at rest and postural): amplitude
It will be assessed by the mean angular amplitude measured using motion sensors placed on the hand and arm at six weeks post-injection.
Measured: 7,5 months
The effect of botulinum toxin on the Parkinsonian tremor (at rest and postural): frequency
It will be assessed by the mean frequency in Hertz (Hz) measured using motion sensors placed on the hand and arm at six weeks post-injection.
Measured: 7,5 months
The effect of botulinum toxin on the patient's experience: life quality
It will be assessed by the delta of the patient's quality of life score on the PDQ-39 self-administered questionnaire between injection and six weeks post-injection.
Measured: 7,5 months
The effect of botulinum toxin on the patient's experience: daily life activities
It will be assessed by the delta of the daily life activities score by the MDS-UPDRS scale, parts one and two between injection and six weeks post-injection.
Measured: 7,5 months
The safety of use for botulinum toxin: muscle weakness (1)
It will be assessed by the delta of the measurement in Newton of the manual dynamometer, for the treated hand, between injection and six weeks after injection.
Measured: 7,5 months
The safety of use for botulinum toxin: muscle weakness (2)
It will be assessed by the delta of the severity scores for muscle weakness in the treated hand, on the PGI-S (Patient Global Impression Severity) scale, completed by the patient between the injection and six weeks after the injection.
Measured: 7,5 months
The safety of use for botulinum toxin: adverse events
It will be assessed by all the adverse events collected during the study.
Measured: 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Sep 2026
- Study startDec 2026 (estimated)
- Primary completionDec 2029 (estimated)
- Study completionDec 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for PARKINSON DISEASE (Disorder)Studies of the same condition, open and under way.
- More trials run by University Hospital, ToulouseThe 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 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 39 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Toulouse
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Clémence Leung, MD, Principal investigator, University Hospital, Toulouse
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07822893
- Sponsor's protocol ID
- RC31/25/0444
- Other IDs
- PHRC 24-79, 2026-525862-23-00
- Acronym
- TOX PARK
- Status last verified
- Nov 2026
- First submitted
- 10 Sep 2026
- Last updated
- 4 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 4 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of the Effect of Botulinum Toxin on Resting Tremor of the Refractory Upper Limb in Parkinsonians, Cross-over Study, Double Blind and Placebo-controlled
- ClinicalTrials.gov ID
- NCT07822893
- Acronym / sponsor ID
- TOX PARK / RC31/25/0444
- Conditions
- PARKINSON DISEASE (Disorder)
- Keywords
- parkinson disease, resistant tremor, botulinic toxin, precision medicine
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 39 participants (estimated)
- Lead sponsor
- University Hospital, ToulouseUniversity, hospital or other
- Study start
- Dec 2026 (estimated)
- Primary completion
- Dec 2029 (estimated)
- Study completion
- Dec 2029 (estimated)
- First posted
- 16 Sep 2026 (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.
Tremor is one of the most common symptoms in Parkinson Disease (PD), affecting almost 60% of patients. There is currently no specific treatment for tremor in PD, and 30% of patients develop drug-resistant tremor, making its management more complex. Botulinum toxin (BT) is widely used in neurology, but few studies have been carried out on the effect of BT in parkinsonian tremor without consensus on its management in parkinsonian patients. In this study, the investigators therefore propose to evaluate the effect of BT injected using precision medicine in the treatment of refractory resting tremor in patients with PD, compared with placebo injection.
Detailed description
Parkinson's disease (PD) is the second most common neurodegenerative disease. Tremor is one of the most common symptoms, affecting almost 60% of patients. It has a considerable impact on their quality of life, causing psychosocial stress in over 25% of patients. There is currently no specific treatment for tremor in PD, and 30% of patients develop drug-resistant tremor, making its management more complex. Botulinum toxin (BT) has been approved in France in 1994 and is widely used in neurology. To date, few studies have been carried out on the effect of BT in parkinsonian tremor: most have been open-label and have mixed parkinsonian patients and patients with essential tremor. Therefore, there is no consensus on the management of tremor in patients with PD. Nevertheless, there is a real need for treatment of refractory tremor, particularly in elderly patients, patients who cannot tolerate high doses of medication or patients who are ineligible for neurostimulation. In this study, the investigators therefore propose to evaluate the effect of BT injected using precision medicine in the treatment of refractory resting tremor in parkinsonian patients, compared with placebo injection. The investigators hypothesize that BT treatment improves parkinsonian tremor in a clinically relevant way compared to placebo injection using an optimized and personalized injection technique (doses of toxin and muscles injected). The drug will be injected intramuscularly into the muscles identified as responsible for the tremor, by an investigator specialising in injections. PD patients with resistant tremor will be included and followed up in this study for one year. BT or placebo will be injected at 6 months apart in all patients thanks to the cross over study design.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Botulinum toxin followed by placebo arm | Experimental | Drug: Injection of Dysport then placeboIn this cross-over study, the patient will be his or her own control. The patient will receive both treatments at 6 months apart: DYSPORT followed by the placebo (the order of injections has been randomly assigned). |
| Placebo followed by botulinum toxin arm | Experimental | Drug: Injection of placebo then DysportIn this cross-over study, the patient will be his or her own control. The patient will receive both treatments at 6 months apart: placebo followed by DYSPORT (the order of injections has been randomly assigned). |
Who may qualify
- Ages
- 40 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Patients with PD defined according to UKPDSBB criteria;
- Men and women aged between 40 and 80 years;
- Patients with troublesome rest tremor assessed by the CGI-S scale ≥ 3 and persistent despite the initiation of ≥ two anti-parkinsonian treatments (levodopa, dopaminergic agonist, anticholinergic), which defines drug-resistant parkinsonian tremor;
- Patients naïve to botulinum toxin treatment;
- Patients whose antiparkinsonian treatment has been stable for at least 4 weeks prior to inclusion and for the duration of the study;
Key exclusion criteria (11 listed)
- Patients with tremors related to a pathology other than PD;
- Patients with atypical parkinsonian syndrome;
- Patients treated with drugs which have the adverse effect of causing the appearance or aggravation of tremors: lithium, sodium valproate, levetiracetam, benzodiazepines, corticosteroids, thyroid hormones, ciclosporin, alcohol, tricyclic antidepressants, theophillyne, terbutaline, antipsychotics (excluding clozapine) ;
- Patients with hypersensitivity to the active substance or to one of the excipients (human albumin, lactulose);
- patients with atrophy of the target muscle
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 |
|---|---|---|
| Injection of Dysport then placeboBoth treatments, first DYSPORT 500UI for 6 months then placebo, also for 6 months, will be administered intramuscularly using the same schedule and procedures thus allowing the blind to be maintained. The two injections will be carried at 6 months apart: the drug will be injected intramuscularly, into the muscles identified as responsible for the tremor, by an investigator specialized in carrying out injections. The doses injected will depend on the severity of the tremor and the number of muscles injected, which is conditioned by the tremor phenotype. | Drug | Botulinum toxin followed by placebo arm |
| Injection of placebo then DysportBoth treatments, first placebo for 6 months then DYSPORT 500UI, also for 6 months, will be administered intramuscularly using the same schedule and procedures thus allowing the blind to be maintained. The two injections will be carried at 6 months apart: the drug will be injected intramuscularly, into the muscles identified as responsible for the tremor, by an investigator specialized in carrying out injections. The doses injected will depend on the severity of the tremor and the number of muscles injected, which is conditioned by the tremor phenotype. | Drug | Placebo followed by botulinum toxin arm |
Primary outcome
The effect of botulinum toxin on the resting tremor of the upper limb refractory to treatments
Time frame: 7,5 months
It will be assessed by the PGI-C (Patient Global Impression-Change) score completed by the patient six weeks after injection and compared between treatments.
17 secondary outcomes
The effect of botulinum toxin on the resting tremor: evolution evaluated by the investigator
Time frame: 7,5 months
The effect of botulinum toxin on the resting tremor: severity evaluated by the investigator
Time frame: 7,5 months
The effect of botulinum toxin on the resting tremor: amplitude evaluated by the investigator
Time frame: 7,5 months
The effect of botulinum toxin on the resting tremor: patient-assessed severity
Time frame: 7,5 months
The effect of botulinum toxin on the postural tremor: evolution evaluated by the investigator
Time frame: 7,5 months
The effect of botulinum toxin on the postural tremor: severity evaluated by the investigator
Time frame: 7,5 months
The effect of botulinum toxin on the postural tremor: amplitude evaluated by the investigator
Time frame: 7,5 months
The effect of botulinum toxin on the postural tremor: patient-assessed change
Time frame: 7,5 months
The effect of botulinum toxin on the postural tremor: patient-assessed severity
Time frame: 7,5 months
The effect of botulinum toxin on the Parkinsonian tremor (at rest and postural): duration
Time frame: 12 months
The effect of botulinum toxin on the Parkinsonian tremor (at rest and postural): amplitude
Time frame: 7,5 months
The effect of botulinum toxin on the Parkinsonian tremor (at rest and postural): frequency
Time frame: 7,5 months
The effect of botulinum toxin on the patient's experience: life quality
Time frame: 7,5 months
The effect of botulinum toxin on the patient's experience: daily life activities
Time frame: 7,5 months
The safety of use for botulinum toxin: muscle weakness (1)
Time frame: 7,5 months
The safety of use for botulinum toxin: muscle weakness (2)
Time frame: 7,5 months
The safety of use for botulinum toxin: adverse events
Time frame: 12 months
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 4 Nov 2026.
- Individual participant dataSharing planned: Undecided
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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.
Clémence Leung, MD principal investigator
University Hospital, Toulouse
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study of PARKINSON DISEASE (Disorder), run by University Hospital, Toulouse at 2 sites in France.
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 7 inclusion and 11 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: opening soon, as of the sponsor's last update on 4 Nov 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 France. 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 phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
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 Clémence Leung, MD (05 61 77 61 76 ext. +33, leung.c@chu-toulouse.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The effect of botulinum toxin on the resting tremor of the upper limb refractory to treatments (time frame: 7,5 months). 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 4 Nov 2026.