Istradefylline for Parkinson Disease With Cognitive Impairment

NCT05333549 | Completed Phase 2 Results FDA Drug

• 1 other identifier: HM20022119
• Study Type: interventional
• Target: 15
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of this research study is to determine whether istradefylline improves cognition in individuals with Parkinson disease with cognitive impairment.

Conditions

Parkinson Disease; Cognitive Impairment

Outcome Measures

Primary Outcomes (1)

• Change in Executive Function - Card Sort Test

  Executive function will be assessed using the Card Sort Test from the NIH Toolbox Cognition Battery. It measures the number of times the participant successfully figures out the rule and matches 10 cards in a row (maximum of 6). So the score range is 0-6. Interpretation: Low numbers (e.g., 0-2 categories) reflect poor abstract reasoning and an inability to use feedback to guide behavior. A score of 6 is the standard normal score for younger adults and a score of 3 or higher is normal or adjusted cut-off for adults 60+.

  Baseline to 26 weeks

Secondary Outcomes (6)

• Change in Neurocognitive Outcomes

  Baseline to 26 weeks

• Change in Recall

  Baseline to 26 weeks

• Change in Oral Fluency

  Baseline to 26 weeks

• Change in Executive Function - Trail Making Test

  Baseline to 26 weeks

• Change in Cognitive Status-Montreal Cognitive Assessment

  Baseline to 26 weeks

Study Arms (1)

Usual care plus istradefylline

EXPERIMENTAL

Participants will receive usual care, and in addition, will be asked to take istradefylline daily for 26 weeks.

Drug: Istradefylline medication

Interventions

Istradefylline medication DRUG

2 weeks on istradefylline 20mg daily, 2 weeks on istradefylline 40mg with the ability to adjust other antiparkinsonian medications, and 22 weeks on istradefylline 40mg and stable antiparkinsonian medications

Usual care plus istradefylline

Eligibility Criteria

• Age: 50 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Meet criteria for probable Parkinson disease dementia or PD-MCI (mild cognitive impairment)
• Age greater than 50
• Hoehn and Yahr stage \< 4 in "on" state
• Currently taking carbidopa/levodopa
• Antiparkinsonian medications stable for at least 4 weeks prior to baseline visit
• Cholinesterase inhibitor dose stable for 8 weeks prior to baseline visit

You may not qualify if:

• Meet criteria for dementia with Lewy bodies, including dementia onset prior to or within 1 year of parkinsonism onset
• Presence of troublesome dyskinesias
• Pregnancy or possibility of becoming pregnant during the study period.
• Moderate or severe hepatic impairment
• dementia too severe to complete study measures or to adhere to medication schedule

Sponsors & Collaborators

• Virginia Commonwealth University: lead
• Kyowa Kirin, Inc.: collaborator

Study Sites (1)

Virginia Commonwealth University

Richmond, Virginia, 23298, United States

Location

MeSH Terms

Conditions

Parkinson Disease; Cognitive Dysfunction

Condition Hierarchy (Ancestors)

Parkinsonian Disorders; Basal Ganglia Diseases; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Movement Disorders; Synucleinopathies; Neurodegenerative Diseases; Cognition Disorders; Neurocognitive Disorders; Mental Disorders

Results Point of Contact

• Title: Matthew Barrett, MD/ Professor of Neurology
• Organization: Virginia Commonwealth University

matthew.barrett@vcuhealth.org

804-628-2022

Study Officials

• Matthew Barrett, MD

  Virginia Commonwealth University

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: SUPPORTIVE CARE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 11, 2022
• First Posted: April 19, 2022
• Study Start: July 18, 2022
• Primary Completion: June 9, 2025
• Study Completion: June 9, 2025
• Last Updated: September 23, 2026
• Results First Posted: September 23, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)