Parkinson DiseasePhase 2/3NCT04857359
Dipraglurant (ADX48621) for the Treatment of Patients With Parkinson's Disease Receiving Levodopa-based Therapy
A Phase 2/3 study testing Dipraglurant in people with Parkinson Disease and Dyskinesia, Drug-Induced, run by Addex Pharma S.A. at 41 sites in United States.
Trial summary
This study is designed to evaluate the safety and efficacy of dipraglurant in PD patients with dyskinesia (randomized 1:1 to receive active or placebo) for 12 weeks (1 week at 150 mg per day and 11 weeks at 300 mg per day). The primary efficacy assessment will be based on the Unified Dyskinesia Rating Scale (UDysRS). Read more about this study
- Who is it for?
- Ages 30 to 85 years
- Conditions the study is for
- Parkinson Disease, Dyskinesia, Drug-Induced, Dyskinesias
- What is being tested?
- Dipraglurant
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 25 participants
- Where
- 41 sitesUnited States
- Study dates
- 6 Aug 2021to 15 Aug 2022
- Phase
- Phase 2/3
- 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 30 to 85 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients with Parkinson's Disease on a stable regimen of antiparkinson's medications, including a levodopa preparation administered not less than 3 times daily.
- Meet protocol-specified criteria for moderate to severe dyskinesia symptoms based on UDysRS and Movement Disorder Society - Unified Parkinson's Disease Rating Scale (MDS-UPDRS) assessments.
- Meet protocol specified criteria for ON time with troublesome dyskinesia based on a standard PD home diary.
Who cannot join
- Prior surgical treatment for Parkinson's Disease (e.g., deep brain stimulation).
- Other neurological disease (including psychiatric disease and/or cognitive impairment) that, in the opinion of the investigator, would affect the patient's ability to complete study assessments.
- Other significant medical condition that may affect the safety of the patient or preclude adequate participation in the study.
- Pregnant or breast-feeding. Female patients who are of child-bearing potential must be using adequate contraceptive methods (e.g. oral contraceptive, double-barrier method, intra-uterine device, intra-muscular hormonal contraceptive), and have a negative pregnancy test at Screening.
- Other protocol-defined inclusion and exclusion criteria may apply
Trial locations and contacts
41 sites in 1 country.
41 sites in 1 country
United States41 sites
Abington Neurologic Associates
Abington, Pennsylvania, 19001-3816
University of New Mexico Health Sciences Center
Albuquerque, New Mexico, 87106-2719
Emory University
Atlanta, Georgia, 30329
Augusta University
Augusta, Georgia, 30912
Henry Ford Health System
Bingham Farms, Michigan, 48025-4334
Parkinson's Disease and Movement Disorders Center of Boca Raton Inc
Boca Raton, Florida, 33486
Cooper University Hospital
Camden, New Jersey, 08103
Rush University Medical Center
Chicago, Illinois, 60612
The Cleveland Clinic Foundation
Cleveland, Ohio, 44195
The Ohio State University Wexner Medical Center
Columbus, Ohio, 43210-1267
David L Kreitzman MD PC
Commack, New York, 11725
NeuroStudies.net, LLC - ClinEdge - PPDS
Decatur, Georgia, 30033
Michigan State University
East Lansing, Michigan, 48824
Rocky Mountain Movement Disorders Center
Englewood, Colorado, 80113
Neuro-Pain Medical Center
Fresno, California, 93710
Josephson Wallack Munshower Neurology PC
Indianapolis, Indiana, 46256
University of California Irvine Medical Center
Irvine, California, 92697
University of Kansas Medical Center
Kansas City, Kansas, 66160
Evergreen Hospital Medical Center
Kirkland, Washington, 98034
University of Wisconsin Hospitals and Clinics
Madison, Wisconsin, 53705
Froedtert and The Medical College of Wisconsin
Milwaukee, Wisconsin, 53226-0509
Vanderbilt University Medical Center
Nashville, Tennessee, 37232
Rutgers, the State University of New Jersey
New Brunswick, New Jersey, 08901
Icahn School of Medicine at Mount Sinai
New York, New York, 10029
Meridian Clinical Research (Norfolk, Virginia)
Norfolk, Virginia, 23502-3932
Renstar Medical Research -21 NE 1st Ave
Ocala, Florida, 34471
AES - DRS - Synexus Clinical Research US, Inc. - Orlando
Orlando, Florida, 32806
Neurology Associates of Ormond Beach
Ormond Beach, Florida, 32174
Stanford Neuroscience Health Center
Palo Alto, California, 94304
University of Pennsylvania
Philadelphia, Pennsylvania, 19107
Xenosciences Inc
Phoenix, Arizona, 85004
UT Health Science Center, San Antonio
San Antonio, Texas, 78229-3901
Avera Medical Group
Sioux Falls, South Dakota, 57105
Southern Illinois University School of Medicine
Springfield, Illinois, 62702
Suncoast Neuroscience Associates Inc
St. Petersburg, Florida, 33712
University of South Florida
Tampa, Florida, 33612-4799
University of Toledo, Gardner-McMaster Parkinson Center
Toledo, Ohio, 43614
Pacific Neuroscience Institute
Torrance, California, 90503
Chase Family Movement Disorders Center - Vernon
Vernon, Connecticut, 06066
Geodyssey Research LLC
Vero Beach, Florida, 32960
Sentara Neurology Specialists
Virginia Beach, Virginia, 23456
About this study
Official title: Phase 2b/3, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Safety and Efficacy of Dipraglurant (ADX48621) for the Treatment of Dyskinesia in Patients With Parkinson's Disease Receiving Levodopa-based Therapy
This study is designed to evaluate the safety and efficacy of dipraglurant in PD patients with dyskinesia (randomized 1:1 to receive active or placebo) for 12 weeks (1 week at 150 mg per day and 11 weeks at 300 mg per day). The primary efficacy assessment will be based on the Unified Dyskinesia Rating Scale (UDysRS). Patients who complete the 12-week blinded treatment period may have the option to roll into an open-label safety extension study for an additional 12-month treatment period.
- Conditions
- Parkinson Disease, Dyskinesia, Drug-Induced, Dyskinesias
- Being tested
- Dipraglurant, Placebo
- Keywords
- Parkinson's disease, Dyskinesia, Levodopa-induced Dyskinesia
- Medical subject headings
- Parkinson Disease, Dyskinesia, Drug-Induced, Dyskinesias
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
DipraglurantDrug
Also called ADX48621
Oral 50mg and 100mg tablet
PlaceboDrug
Oral matching placebo tablet
| Study group | Role | What they receive |
|---|---|---|
| Dipraglurant TID | Experimental | Not described Receives: Drug: Dipraglurant |
| Placebo TID | Placebo comparator | Not described Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change from baseline on the Unified Dyskinesia Rating Scale (UDysRS) total score
The UDysRS is a dyskinesia rating scale scored from 0-104 that evaluates involuntary movements associated with PD. A higher score indicates more severe dyskinesia.
Measured: Baseline (Day 1) to Week 12
Secondary outcomes (2)
Change from baseline in ON time without troublesome dyskinesia based on a standardized PD diary
A PD home diary is used to score 5 different conditions in 30-minute time intervals: ASLEEP, OFF, ON (ie, had adequate control of PD symptoms) without dyskinesia, ON with non-troublesome dyskinesia, and ON with troublesome dyskinesia.
Measured: Baseline (Day 1) to Week 12
Change from baseline in OFF time based on a standardized PD diary
A PD home diary is used to score 5 different conditions in 30-minute time intervals: ASLEEP, OFF, ON (ie, had adequate control of PD symptoms) without dyskinesia, ON with non-troublesome dyskinesia, and ON with troublesome dyskinesia.
Measured: Baseline (Day 1) to Week 12
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Apr 2021
- Study start6 Aug 2021
- Primary completion17 Jun 2022
- Study completion15 Aug 2022
Why it stopped: Terminated prior to completing enrollment goals due to COVID-related difficulties in recruiting patients
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Parkinson DiseaseStudies 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 2/3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 25 participants (actual)
Sponsor and investigators
- Lead sponsor
- Addex Pharma S.A.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04857359
- Sponsor's protocol ID
- ADX48621-301
- Status last verified
- Aug 2025
- First submitted
- 21 Apr 2021
- Last updated
- 6 Aug 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Phase 2b/3, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Safety and Efficacy of Dipraglurant (ADX48621) for the Treatment of Dyskinesia in Patients With Parkinson's Disease Receiving Levodopa-based Therapy
- ClinicalTrials.gov ID
- NCT04857359
- Acronym / sponsor ID
- ADX48621-301
- Conditions
- Parkinson Disease, Dyskinesia, Drug-Induced, Dyskinesias
- Keywords
- Parkinson's disease, Dyskinesia, Levodopa-induced Dyskinesia
- Phase
- Phase 2/3
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Terminated prior to completing enrollment goals due to COVID-related difficulties in recruiting patients
- Enrolment
- 25 participants (actual)
- Lead sponsor
- Addex Pharma S.A.Industry (pharma, biotech, devices)
- Study start
- 6 Aug 2021 (actual)
- Primary completion
- 17 Jun 2022 (actual)
- Study completion
- 15 Aug 2022 (actual)
- First posted
- 23 Apr 2021 (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 designed to evaluate the safety and efficacy of dipraglurant in PD patients with dyskinesia (randomized 1:1 to receive active or placebo) for 12 weeks (1 week at 150 mg per day and 11 weeks at 300 mg per day). The primary efficacy assessment will be based on the Unified Dyskinesia Rating Scale (UDysRS). Patients who complete the 12-week blinded treatment period may have the option to roll into an open-label safety extension study for an additional 12-month treatment period.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Dipraglurant TID | Experimental | Drug: Dipraglurant |
| Placebo TID | Placebo comparator | Drug: Placebo |
Who may qualify
- Ages
- 30 to 85 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Patients with Parkinson's Disease on a stable regimen of antiparkinson's medications, including a levodopa preparation administered not less than 3 times daily.
- Meet protocol-specified criteria for moderate to severe dyskinesia symptoms based on UDysRS and Movement Disorder Society - Unified Parkinson's Disease Rating Scale (MDS-UPDRS) assessments.
- Meet protocol specified criteria for ON time with troublesome dyskinesia based on a standard PD home diary.
Key exclusion criteria (5 listed)
- Prior surgical treatment for Parkinson's Disease (e.g., deep brain stimulation).
- Other neurological disease (including psychiatric disease and/or cognitive impairment) that, in the opinion of the investigator, would affect the patient's ability to complete study assessments.
- Other significant medical condition that may affect the safety of the patient or preclude adequate participation in the study.
- Pregnant or breast-feeding. Female patients who are of child-bearing potential must be using adequate contraceptive methods (e.g. oral contraceptive, double-barrier method, intra-uterine device, intra-muscular hormonal contraceptive), and have a negative pregnancy test at Screening.
- Other protocol-defined inclusion and exclusion criteria may apply
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 |
|---|---|---|
| DipraglurantAlso: ADX48621Oral 50mg and 100mg tablet | Drug | Dipraglurant TID |
| PlaceboOral matching placebo tablet | Drug | Placebo TID |
Primary outcome
Change from baseline on the Unified Dyskinesia Rating Scale (UDysRS) total score
Time frame: Baseline (Day 1) to Week 12
The UDysRS is a dyskinesia rating scale scored from 0-104 that evaluates involuntary movements associated with PD. A higher score indicates more severe dyskinesia.
2 secondary outcomes
Change from baseline in ON time without troublesome dyskinesia based on a standardized PD diary
Time frame: Baseline (Day 1) to Week 12
Change from baseline in OFF time based on a standardized PD diary
Time frame: Baseline (Day 1) to Week 12
Results and safety
The study was stopped early (reason given: Terminated prior to completing enrollment goals due to COVID-related difficulties in recruiting patients). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Aug 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.
41 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2/3 study testing Dipraglurant in people with Parkinson Disease and Dyskinesia, Drug-Induced, run by Addex Pharma S.A. at 41 sites in United States.
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 3 inclusion and 5 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: stopped early, as of the sponsor's last update on 6 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 41 sites in United States. 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 combined 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.
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?
The study was stopped early (reason given: Terminated prior to completing enrollment goals due to COVID-related difficulties in recruiting patients). Results are not available in the source record.
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?
Change from baseline on the Unified Dyskinesia Rating Scale (UDysRS) total score (time frame: Baseline (Day 1) to Week 12). 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 6 Aug 2025; AzTrials last refreshed its copy on 8 Nov 2026.