Open-label Safety Study of Dipraglurant (ADX48621) in Patients With Parkinson's Disease Receiving Levodopa-based Therapy

August 1, 2025 updated by: Addex Pharma S.A.

An Open-label Safety Study of Dipraglurant (ADX48621) in Patients With Parkinson's Disease Receiving Levodopa-based Therapy With or Without Concomitant Dopaminergic Medications

This open-label study is designed to assess the long-term safety and tolerability of dipraglurant in PD patients for up to 52 weeks (at doses of 150-300 mg per day) for patients that have completed an Addex sponsored double-blind clinical trial of dipraglurant.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Terminated

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
17

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Georgia
      • Augusta, Georgia, United States, 30912
        • Augusta University
    • Kansas
      • Kansas City, Kansas, United States, 66160
        • University of Kansas Medical Center
    • New Jersey
      • New Brunswick, New Jersey, United States, 08901
        • Rutgers, The State University of New Jersey
    • New York
      • New York, New York, United States, 10029
        • Icahn School of Medicine at Mount Sinai
    • Ohio
      • Columbus, Ohio, United States, 43210-1267
        • The Ohio State University Wexner Medical Center
    • Pennsylvania
      • Abington, Pennsylvania, United States, 19001-3816
        • Abington Neurologic Associates
      • Philadelphia, Pennsylvania, United States, 19107
        • University of Pennsylvania

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

30 years to 85 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Completed an Addex randomized controlled study of dipraglurant and, in the judgement of the Investigator, may benefit from open-label treatment
  • Able to take study drug 3 times daily and no less than 3 hours apart
  • Must be taking levodopa not less than 3 times daily throughout the study
  • Must maintain stable regimen of antiparkinson's medications (including levodopa) and be willing to continue the same doses and regimens for the first 4 weeks of the study

Exclusion Criteria:

  • Patient is judged by the Investigator to be inappropriate for the study (for reasons such as, but not limited to, significant noncompliance in the Addex randomized controlled study of dipraglurant)
  • Use of amantadine or amantadine ER throughout the study
  • Use of memantine throughout the study
  • Any use of marijuana or other cannabis/cannabinoid products for the first 4 weeks of study participation

Other protocol-defined inclusion and exclusion criteria may apply

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Dipraglurant TID
Drug: Dipraglurant
Oral 50 mg and 100 mg tablet
Other Names:
  • ADX48621

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Long-term safety and tolerability of dipraglurant as measured by incidence of adverse events
Time Frame: Baseline (Day 1) to Week 52
Testing the safety and tolerability of dipraglurant in patients with Parkinson's Disease Levodopa-induced dyskinesia based on the incidence of adverse events reported by patients and/or as identified by the Investigator based on clinical assessments conducted during the study.
Baseline (Day 1) to Week 52

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Evaluate the continued utility of dipraglurant on dyskinesia as assessed by a change-from-baseline score on the Movement Disorder Society - Unified Parkinson's Disease Rating Scale (MDS-UPDRS).
Time Frame: Baseline (Day 1) to Week 52
The MDS-UPDRS is a Parkinson's Disease (PD) rating scale scored from 0-272; it evaluates progression of disease in patients with PD. A higher score indicates more severe PD.
Baseline (Day 1) to Week 52

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Addex Pharma S.A.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 25, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 17, 2022

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 15, 2022

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 1, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 1, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 11, 2021

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 6, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 1, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • ADX48621-302

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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