Istradefylline for Parkinson Disease With Cognitive Impairment

July 22, 2025 updated by: Virginia Commonwealth University

Istradefylline for Parkinson Disease Cognitive Impairment

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

Study Overview

Status

Status

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

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.

Detailed Description

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.

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.
15

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

Contacts and Locations

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

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • Virginia
      • Richmond, Virginia, United States, 23298
        • Virginia Commonwealth University

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

50 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

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

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: Supportive Care
  • 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: Usual care plus istradefylline
Participants will receive usual care, and in addition, will be asked to take istradefylline daily for 26 weeks.
Drug: Istradefylline medication
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

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
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
Baseline to 26 weeks

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
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.
Baseline to 26 weeks
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.
Baseline to 26 weeks
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.
Baseline to 26 weeks
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.
Baseline to 26 weeks
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.
Baseline to 26 weeks
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
Baseline to 26 weeks

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.
Virginia Commonwealth University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Kyowa Kirin, Inc.

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Matthew Barrett, MD, Virginia Commonwealth University

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.
July 18, 2022

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 9, 2025

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.
June 9, 2025

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).
April 11, 2022

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.
April 11, 2022

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.
April 19, 2022

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.
July 28, 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.
July 22, 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.
July 1, 2025

More Information

Terms related to this study

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.
  • HM20022119

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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