A Late Phase II Clinical Trial of KDT-3594 in Patients With Parkinson's Disease

A Late Phase II Clinical Trial of KDT-3594 in Patients With Advanced Parkinson's Disease With Levodopa

This trial is a late phase II, multicenter, randomized, double-blind, placebo-controlled, parallel group trial to evaluate the efficacy, safety, and pharmacokinetics of KDT-3594 administered at escalating doses ranging from 0.25 to 2 mg per day for 17 weeks in patients with advanced PD with levodopa.

Study Overview

• Status: Active, not recruiting
• Conditions: Parkinson Disease
• Intervention / Treatment: Drug: Placebo; Drug: KDT-3594

Detailed Description

This trial is a late phase II, multicenter, randomized, double-blind, placebo-controlled, parallel group trial to evaluate the efficacy, safety, and pharmacokinetics of KDT-3594 administered once daily in patients with advanced PD with levodopa.

• Study Type: Interventional
• Enrollment (Estimated): 150
• Phase: Phase 2

Contacts and Locations

Study Locations

• Japan
  • Multiple Locations, Japan
    • Research Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients diagnosed with PD according to the Parkinson's disease society brain bank clinical diagnostic criteria of the UK Parkinson's Disease Society
• Patients who are being treated with levodopa or levodopa combination drugs and have any of the following troublesome symptoms or conditions:
• Patients with wearing-off phenomenon
• Patients with ON-/OFF-phenomenon
• Patients with no-on/delayed on phenomenon
• Patients with inadequate response to levodopa

Exclusion Criteria:

• Patients suspected of having parkinsonism other than PD based on medical history, physical findings, laboratory test values, dopamine transporter-single photon emission computed tomography (DAT-SPECT), etc.
• Patients who have undergone neurosurgical therapy for PD (e.g., stereotactic thalamotomy and pallidotomy and deep brain stimulation) or who are scheduled to undergo surgical therapy during the trial period
• Patients complicated with overt dementia or a Mini-Mental State Examination (MMSE) score of < 24 at the start of the screening period

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: KDT-3594; KDT-3594 capsules will be orally administered at escalating doses ranging from 0.25 to 2 mg per day for 17 weeks.	Drug: KDT-3594; Oral administration
Placebo Comparator: Placebo; Placebo capsules will be orally administered at escalating doses ranging from 0.25 to 2 mg per day for 17 weeks.	Drug: Placebo; Oral administration

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline in the MDS-UPDRS Part II+III (ON-time) total score at Week 17 of the treatment period	MDS-UPDRS is a multimodal scale assessing impairment and disability consisting of 4 parts. (Part I; 13 items) non-motor experiences of daily living, (Part II; 13 items) motor experiences of daily living completed by the participants, (Part III; 33 items) motor examination of PD and was administered by the rater, and (Part IV; 6 items) motor complication integrates participant-derived information with the rater's clinical observations and judgements and is completed by the rater. For each question, a numeric score was assigned between 0-4, where 0 = Normal, 1 = Slight, 2 = Mild, 3 = Moderate, 4 = Severe. In all parts, a higher score indicated more severe symptoms of PD, and the score range of each part are as follows.; Part I: 0-52; Part II: 0-52; Part III: 0-132; Part IV: 0-24; Total Score: 0-260; Part II+III: 0-184 (MDS-UPDRS Part II and III combined score equals the sum of Parts II and III (range 0-184)).	Up to 17 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline in the MDS-UPDRS Part II+III (ON-time) total score	MDS-UPDRS is a multimodal scale assessing impairment and disability consisting of 4 parts. (Part I; 13 items) non-motor experiences of daily living, (Part II; 13 items) motor experiences of daily living completed by the participants, (Part III; 33 items) motor examination of PD and was administered by the rater, and (Part IV; 6 items) motor complication integrates participant-derived information with the rater's clinical observations and judgements and is completed by the rater. For each question, a numeric score was assigned between 0-4, where 0 = Normal, 1 = Slight, 2 = Mild, 3 = Moderate, 4 = Severe. In all parts, a higher score indicated more severe symptoms of PD, and the score range of each part are as follows.; Part I: 0-52; Part II: 0-52; Part III: 0-132; Part IV: 0-24; Total Score: 0-260; Part II+III: 0-184 (MDS-UPDRS Part II and III combined score equals the sum of Parts II and III (range 0-184)).	Up to 17 weeks
Change from baseline in the MDS-UPDRS Part I, II, III, and IV (ON-time) total score	MDS-UPDRS is a multimodal scale assessing impairment and disability consisting of 4 parts. (Part I; 13 items) non-motor experiences of daily living, (Part II; 13 items) motor experiences of daily living completed by the participants, (Part III; 33 items) motor examination of PD and was administered by the rater, and (Part IV; 6 items) motor complication integrates participant-derived information with the rater's clinical observations and judgements and is completed by the rater. For each question, a numeric score was assigned between 0-4, where 0 = Normal, 1 = Slight, 2 = Mild, 3 = Moderate, 4 = Severe. In all parts, a higher score indicated more severe symptoms of PD, and the score range of each part are as follows.; Part I: 0-52; Part II: 0-52; Part III: 0-132; Part IV: 0-24; Total Score: 0-260; Part II+III: 0-184 (MDS-UPDRS Part II and III combined score equals the sum of Parts II and III (range 0-184)).	Up to 17 weeks
Response rate in the MDS-UPDRS Part III (ON-time) total score	MDS-UPDRS is a multimodal scale assessing impairment and disability consisting of 4 parts. (Part I; 13 items) non-motor experiences of daily living, (Part II; 13 items) motor experiences of daily living completed by the participants, (Part III; 33 items) motor examination of PD and was administered by the rater, and (Part IV; 6 items) motor complication integrates participant-derived information with the rater's clinical observations and judgements and is completed by the rater. For each question, a numeric score was assigned between 0-4, where 0 = Normal, 1 = Slight, 2 = Mild, 3 = Moderate, 4 = Severe. In all parts, a higher score indicated more severe symptoms of PD, and the score range of each part are as follows.; Part I: 0-52; Part II: 0-52; Part III: 0-132; Part IV: 0-24; Total Score: 0-260; Part II+III: 0-184 (MDS-UPDRS Part II and III combined score equals the sum of Parts II and III (range 0-184)).	Up to 17 weeks
Change from baseline in the proportion of OFF-time in awake time		Up to 17 weeks
Change from baseline in OFF-time		Up to 17 weeks
Incidence of adverse events and treatment-related adverse events		Up to 17 weeks

Collaborators and Investigators

• Sponsor: Kissei Pharmaceutical Co., Ltd.
• Investigators: Study Director: Yoshitaka Shimizu, Kissei Pharmaceutical Co., Ltd.

Study record dates

Study Major Dates

• Study Start (Actual): December 16, 2024
• Primary Completion (Estimated): April 1, 2026
• Study Completion (Estimated): April 1, 2026

Study Registration Dates

• First Submitted: November 26, 2024
• First Submitted That Met QC Criteria: December 3, 2024
• First Posted (Actual): December 9, 2024

Study Record Updates

• Last Update Posted (Actual): March 3, 2026
• Last Update Submitted That Met QC Criteria: February 27, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Synucleinopathies; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neurodegenerative Diseases; Movement Disorders; Parkinsonian Disorders; Basal Ganglia Diseases; Parkinson Disease
• Other Study ID Numbers: KDT1203; Under registration (Registry Identifier: jRCT)

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: No
• Studies a U.S. FDA-regulated device product: No