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Completed

NCT Number: NCT05333549

Istradefylline for Parkinson Disease With Cognitive Impairment

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

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Key information

Conditions

Parkinson Disease Basal Ganglia Diseases Brain Diseases Central Nervous System Diseases Cognition Disorders Cognitive Dysfunction Cognitive Impairment Mental Disorders Movement Disorders Nervous System Diseases Neurocognitive Disorders Neurodegenerative Diseases Parkinsonian Disorders Synucleinopathies

Age range

50 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Virginia Commonwealth University

Richmond, Virginia, 23298, United States

About this study

Istradefylline has been approved by the U. S. Food and Drug Administration (FDA) to reduce "off" episodes in Parkinson disease. The period when levodopa has a positive effect on Parkinson's symptoms is called on-time. Once the medication stops working, a so called "off" episode starts, where symptoms recur. Usual care for treatment of Parkinson disease with cognitive impairment is use of cognition enhancing medications also called cholinesterase inhibitors. In this study, participants will receive usual care, and in addition, they will be asked to take istradefylline daily for 26 weeks.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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

Exclusion criteria

  • 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

Treatment and study plan

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

Primary outcomes

  1. Change in executive function - Card Sort test

    Time frame: Baseline to 26 weeks

    Executive function will be assessed using the Card Sort Test from the NIH Toolbox Cognition Battery. Participants will be assessed at baseline, 4 weeks, 14 weeks, and 26 weeks

Secondary outcomes

  1. Change in neurocognitive outcomes

    Time frame: Baseline to 26 weeks

    NIH Toolbox Cognition Battery (NTCB) consists of multiple self-report and clinician reported tests. The assessments can be completed on a tablet device and a composite as well as sub-scores are calculated. Higher scores are indicative of better functioning. Participants will be assessed at baseline, 4 weeks, 14 weeks, and 26 weeks.

  2. Change in recall

    Time frame: Baseline to 26 weeks

    Immediate and delayed recall will be assessed using the Hopkins Verbal Learning Test - Revised, which will be administered by a trained clinician. Higher scores indicate better recall. Participants will be assessed at baseline, 4 weeks, 14 weeks, and 26 weeks.

  3. Change in oral fluency

    Time frame: Baseline to 26 weeks

    In the Controlled Oral Word Association Test (FAS, animals) (COWAT) the participant is asked to make verbal associations to different letters of the alphabet by saying all the words which they can think of beginning with a given letter. Higher scores indicate better oral fluency. Participants will be assessed at baseline, 4 weeks, 14 weeks, and 26 weeks.

  4. Change in executive function - Trail Making Test

    Time frame: Baseline to 26 weeks

    Participants will complete the Trail Making Test (TMT) which is a timed test of executive function. Scores are the number of seconds needed to complete the test with higher scores indicate poorer executive function. Participants will be assessed at baseline, 4 weeks, 14 weeks, and 26 weeks.

  5. Change in cognitive status

    Time frame: Baseline to 26 weeks

    Participant's cognitive status will be assessed using the Montreal Cognitive Assessment score. Higher scores indicated better cognitive status. Participants will be assessed at baseline, 4 weeks, 14 weeks, and 26 weeks.

  6. Change in higher cortical functions

    Time frame: Baseline to 26 weeks

    The Dementia Rating Scale-2 (DRS-2) measures deficits in a large range of higher cortical functions and differentiates deficits of varying severity levels. The DRS-2 yields five subscales as well as an overall cognitive functioning score. Higher scores higher impairment. Participants will be assessed at baseline, 4 weeks, 14 weeks, and 26 weeks

Sponsors and collaborators

Lead sponsor

Virginia Commonwealth University

Other

Collaborators

  • Kyowa Kirin, Inc.

Registry information

Official study title

Istradefylline for Parkinson Disease Cognitive Impairment

Important dates

Study start
2022
Primary completion
2025
Study completion
2025
First posted
Apr 19, 2022
Registry last updated
Jul 28, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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