Dipraglurant (ADX48621) for the Treatment of Patients With Parkinson's Disease Receiving Levodopa-based Therapy

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.

Study Overview

• Status: Terminated
• Conditions: Parkinson Disease; Dyskinesias; Dyskinesia, Drug-Induced
• Intervention / Treatment: Drug: Dipraglurant; Drug: Placebo

• Study Type: Interventional
• Enrollment (Actual): 25
• Phase: Phase 2; Phase 3

Contacts and Locations

Study Locations

• United States
  • Arizona
    • Phoenix, Arizona, United States, 85004
      • Xenosciences Inc
  • California
    • Fresno, California, United States, 93710
      • Neuro-Pain Medical Center
    • Irvine, California, United States, 92697
      • University of California Irvine Medical Center
    • Palo Alto, California, United States, 94304
      • Stanford Neuroscience Health Center
    • Torrance, California, United States, 90503
      • Pacific Neuroscience Institute
  • Colorado
    • Englewood, Colorado, United States, 80113
      • Rocky Mountain Movement Disorders Center
  • Connecticut
    • Vernon, Connecticut, United States, 06066
      • Chase Family Movement Disorders Center - Vernon
  • Florida
    • Boca Raton, Florida, United States, 33486
      • Parkinson's Disease and Movement Disorders Center of Boca Raton Inc
    • Ocala, Florida, United States, 34471
      • Renstar Medical Research -21 NE 1st Ave
    • Orlando, Florida, United States, 32806
      • AES - DRS - Synexus Clinical Research US, Inc. - Orlando
    • Ormond Beach, Florida, United States, 32174
      • Neurology Associates of Ormond Beach
    • Saint Petersburg, Florida, United States, 33712
      • Suncoast Neuroscience Associates Inc
    • Tampa, Florida, United States, 33612-4799
      • University of South Florida
    • Vero Beach, Florida, United States, 32960
      • Geodyssey Research LLC
  • Georgia
    • Atlanta, Georgia, United States, 30329
      • Emory University
    • Augusta, Georgia, United States, 30912
      • Augusta University
    • Decatur, Georgia, United States, 30033
      • NeuroStudies.net, LLC - ClinEdge - PPDS
  • Illinois
    • Chicago, Illinois, United States, 60612
      • Rush University Medical Center
    • Springfield, Illinois, United States, 62702
      • Southern Illinois University School of Medicine
  • Indiana
    • Indianapolis, Indiana, United States, 46256
      • Josephson Wallack Munshower Neurology PC
  • Kansas
    • Kansas City, Kansas, United States, 66160
      • University of Kansas Medical Center
  • Michigan
    • Bingham Farms, Michigan, United States, 48025-4334
      • Henry Ford Health System
    • East Lansing, Michigan, United States, 48824
      • Michigan State University
  • New Jersey
    • Camden, New Jersey, United States, 08103
      • Cooper University Hospital
    • New Brunswick, New Jersey, United States, 08901
      • Rutgers, The State University of New Jersey
  • New Mexico
    • Albuquerque, New Mexico, United States, 87106-2719
      • University of New Mexico Health Sciences Center
  • New York
    • Commack, New York, United States, 11725
      • David L Kreitzman MD PC
    • New York, New York, United States, 10029
      • ICAHN School of Medicine at Mount Sinai
  • Ohio
    • Cleveland, Ohio, United States, 44195
      • The Cleveland Clinic Foundation
    • Columbus, Ohio, United States, 43210-1267
      • The Ohio State University Wexner Medical Center
    • Toledo, Ohio, United States, 43614
      • University of Toledo, Gardner-McMaster Parkinson Center
  • Pennsylvania
    • Abington, Pennsylvania, United States, 19001-3816
      • Abington Neurologic Associates
    • Philadelphia, Pennsylvania, United States, 19107
      • University of Pennsylvania
  • South Dakota
    • Sioux Falls, South Dakota, United States, 57105
      • Avera Medical Group
  • Tennessee
    • Nashville, Tennessee, United States, 37232
      • Vanderbilt University Medical Center
  • Texas
    • San Antonio, Texas, United States, 78229-3901
      • UT Health Science Center, San Antonio
  • Virginia
    • Norfolk, Virginia, United States, 23502-3932
      • Meridian Clinical Research (Norfolk, Virginia)
    • Virginia Beach, Virginia, United States, 23456
      • Sentara Neurology Specialists
  • Washington
    • Kirkland, Washington, United States, 98034
      • Evergreen Hospital Medical Center
  • Wisconsin
    • Madison, Wisconsin, United States, 53705
      • University of Wisconsin Hospitals and Clinics
    • Milwaukee, Wisconsin, United States, 53226-0509
      • Froedtert and the Medical College of Wisconsin

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 26 years to 81 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• 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.

Exclusion Criteria:

• 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Dipraglurant TID	Drug: Dipraglurant; Oral 50mg and 100mg tablet; Other Names: ADX48621
Placebo Comparator: Placebo TID	Drug: Placebo; Oral matching placebo tablet

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	Baseline (Day 1) to Week 12

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	Baseline (Day 1) to Week 12

Collaborators and Investigators

• Sponsor: Addex Pharma S.A.

Study record dates

Study Major Dates

• Study Start (Actual): August 6, 2021
• Primary Completion (Actual): June 17, 2022
• Study Completion (Actual): August 15, 2022

Study Registration Dates

• First Submitted: April 21, 2021
• First Submitted That Met QC Criteria: April 21, 2021
• First Posted (Actual): April 23, 2021

Study Record Updates

• Last Update Posted (Actual): August 6, 2025
• Last Update Submitted That Met QC Criteria: August 1, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Keywords: Parkinson's disease; Dyskinesia; Levodopa-induced Dyskinesia
• Additional Relevant MeSH Terms: Synucleinopathies; Neurologic Manifestations; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neurodegenerative Diseases; Chemically-Induced Disorders; Movement Disorders; Drug-Related Side Effects and Adverse Reactions; Poisoning; Parkinsonian Disorders; Basal Ganglia Diseases; Neurotoxicity Syndromes; Dyskinesias; Parkinson Disease; Dyskinesia, Drug-Induced
• Other Study ID Numbers: ADX48621-301

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