A Study to Evaluate the Effectiveness of Two Doses of AP-472 as Adjunctive Therapy to Levodopa in Parkinson's Disease (PD) Participants With Motor Fluctuations

September 8, 2026 updated by: Appello Pharmaceuticals, Inc.

Phase 2, Double-blind, Placebo-controlled Study to Evaluate the Effectiveness of Two Doses of AP-472 as Adjunctive Therapy to Levodopa in Parkinson's Disease (PD) Participants With Motor Fluctuations

This is a Phase 2 study in people with Parkinson's disease who experience motor fluctuations while taking levodopa. The study will evaluate how effective two different doses of the study drug AP-472 are when added to levodopa treatment, compared with a placebo.

The study will last about 12 weeks. Participants will be randomly assigned to receive one of the two doses of AP-472 or a placebo. Neither the participants nor the study staff will know which treatment is given.

The study includes a screening period, a 4-week period during which Parkinson's medications must remain stable, and an 8-week treatment period. During the treatment period, limited adjustments to levodopa are allowed if needed.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

150

Phase

  • 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 Locations

  • United States
    • Arkansas
      • Little Rock, Arkansas, United States, 72205-5551
        • Not yet recruiting
        • University of Arkansas for Medical Sciences (Site #208)
    • California
      • Carlsbad, California, United States, 92011
        • Recruiting
        • Profound Research LLC (Site #222)
      • Los Alamitos, California, United States, 90720-3108
        • Recruiting
        • Collaborative Neuroscience Network - Los Alamitos- CenExel - PPDS (Site #217)
      • Los Angeles, California, United States, 90033-5310
        • Not yet recruiting
        • Keck Medicine of USC - USC Healthcare Center 2 (Site #221)
      • Palo Alto, California, United States, 94301
        • Recruiting
        • Parkinson's Research Centers of America (Site #218)
    • Colorado
      • Englewood, Colorado, United States, 80113-2776
        • Recruiting
        • Rocky Mountain Clinical Research - CenExel - PPDS (Site #215)
    • Florida
      • Boca Raton, Florida, United States, 33486
        • Recruiting
        • Parkinson's Disease & Movement Disorders Center of Boca Raton (Site #227)
      • Boca Raton, Florida, United States, 33486
        • Recruiting
        • UM-UHealth at Boca Raton (Site #226)
      • Hallandale, Florida, United States, 33009
        • Recruiting
        • Velocity Clinical Research - Hallandale Beach (Site #228)
      • Miami, Florida, United States, 33136-1051
        • Recruiting
        • University of Miami (Site #220)
      • Orlando, Florida, United States, 32825
        • Recruiting
        • Neurology One (Site #205)
      • Tampa, Florida, United States, 33613-4808
        • Recruiting
        • USF Parkinson's Disease and Movement Disorders Center (Site #206)
    • Georgia
      • Augusta, Georgia, United States, 30912-0020
        • Recruiting
        • Augusta University Medical Center (Site #212)
    • Indiana
      • Indianapolis, Indiana, United States, 46256
        • Recruiting
        • Josephson Wallack Munshower Neurology PC (Site #231)
    • Kansas
      • Kansas City, Kansas, United States, 66160
        • Recruiting
        • The University of Kansas (KU) (Site #216)
    • Kentucky
      • Lexington, Kentucky, United States, 40536-0001
        • Recruiting
        • Kentucky Neuroscience Institute (Site #213)
    • Massachusetts
      • Boston, Massachusetts, United States, 02215-5400
        • Recruiting
        • Beth Israel Deaconess Medical Center (Site #211)
    • Michigan
      • Ann Arbor, Michigan, United States, 48109
        • Recruiting
        • University of Michigan Health System (UMHS) (Site #202)
      • Farmington Hills, Michigan, United States, 48334-2973
        • Recruiting
        • Quest Research Institute - Alcanza - PPDS (Site #201)
    • New Mexico
      • Albuquerque, New Mexico, United States, 87106
        • Recruiting
        • University of New Mexico Health Sciences Center (Site #225)
    • New York
      • New York, New York, United States, 10029-6501
        • Recruiting
        • Mount Sinai School of Medicine (Site #209)
      • New York, New York, United States, 10021
        • Recruiting
        • Joan and Sanford I. Weill Department of Medicine (Site #224)
    • North Carolina
      • Asheville, North Carolina, United States, 28806
        • Recruiting
        • Asheville Neurology Specialists, P.A. (Site #229)
      • Durham, North Carolina, United States, 27705
        • Recruiting
        • Duke Neurological Disorders Clinic (Site #210)
    • Ohio
      • Cleveland, Ohio, United States, 44195-0001
        • Not yet recruiting
        • Cleveland Clinic (Site #223)
      • Columbus, Ohio, United States, 43210
        • Recruiting
        • The Ohio State University Wexner Medical Center (site #207)
    • Tennessee
      • Nashville, Tennessee, United States, 37232
        • Recruiting
        • Vanderbilt University Medical Center (Site #204)
    • Texas
      • Cypress, Texas, United States, 77429
        • Recruiting
        • Horizon Clinical Research: Gill Neuroscience - Houston (Site #232)
      • Round Rock, Texas, United States, 78681-3578
        • Recruiting
        • Central Texas Neurology Consultants (Site #203)
    • Washington
      • Kirkland, Washington, United States, 98034-3013
        • Recruiting
        • EvergreenHealth (Site #219)

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Key Inclusion Criteria:

Participants must meet all of the following criteria to take part in the study:

  1. Be a man or woman between 30 and 80 years of age at the time of screening.
  2. Have a diagnosis of Parkinson's disease, confirmed using standard medical criteria, including slowness of movement and symptoms that affect one side of the body more than the other.
  3. Have mild to moderate Parkinson's disease, defined as stage 3 or lower on the Hoehn and Yahr scale when medications are working ("ON" state).
  4. Experience an average of at least 3 hours of OFF time per day, based on home symptom diaries, with at least 2.5 hours of OFF time each day during the baseline period.
  5. Have a Montreal Cognitive Assessment (MoCA) score of 24 or higher at screening.
  6. Be able to walk independently, with or without the use of a walking aid.
  7. Be able to swallow oral medication.
  8. Have been on a stable Parkinson's medication regimen for at least 4 weeks before screening. Medications known as MAO-B inhibitors must have been stable for at least 12 weeks.
  9. Be taking levodopa at least four times daily (immediate- or controlled-release formulations) or three times daily (extended-release formulations such as Rytary or Crexont).

Key Exclusion Criteria:

Participants cannot take part in the study if any of the following apply:

  1. Have a form of parkinsonism that is not typical Parkinson's disease, such as secondary or atypical parkinsonism.
  2. Have previously received, or plan to receive during the study, advanced Parkinson's therapies such as continuous levodopa or dopamine delivery systems, or Parkinson's disease-related brain surgery.
  3. Have dyskinesias (involuntary movements) that are severe enough, in the study doctor's opinion, to interfere with participation.
  4. Have a history of only certain types of dyskinesias (such as OFF-state, diphasic, myoclonic, or dystonic dyskinesias) without typical peak-dose dyskinesias.
  5. Are currently taking medications that block dopamine, except for low-dose quetiapine (up to 50 mg per day) used for insomnia.
  6. Routinely use on-demand "rescue" Parkinson's medications more than three times per week.

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo
Other: Placebo
Oral tablet
Experimental: Low Dose
AP-472 100 mg per day
Other: Placebo
Oral tablet
Drug: AP-472
Oral tablet
Experimental: High Dose
AP-472 300 mg per day
Drug: AP-472
Oral tablet

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Change from Baseline in average daily OFF time on motor diaries for AP-472 compared to placebo (normalized to 16-hour awake time)
Time Frame: Week 12
Week 12

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change from baseline in ON time without troublesome dyskinesia (normalized to 16 hours)
Time Frame: Week 12
Week 12
Change from baseline in Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part 2 (Motor Experiences of Daily Living (M-EDL)) score
Time Frame: Week 12
For MDS-UPDRS Part II (Motor Experiences of Daily Living, M-EDL) there are 13 items each scored from 0 to 4. The total score range is from 0-52. A higher score indicates worse motor impact on daily activities; lower scores are better.
Week 12
Change from baseline in Parkinson's Disease Questionnaire-39 (PDQ-39) summary index
Time Frame: Week 12
For the Parkinson's Disease Questionnaire-39 (PDQ-39) Summary Index the score is calculated by averaging the 8 domain scores and converting them to a 0-100 scale. A higher score indicates worse health-related quality of life; lower scores are better.
Week 12
Change from baseline in MDS-UPDRS Part III (Motor Examination) score in the best ON state
Time Frame: Week 12
The MDS-UPDRS Part III includes 33 items, each scored from 0 to 4. The total score range is from 0-132. A higher score indicates worse motor impairment; lower scores are better.
Week 12
Change from baseline in Epworth Sleepiness Scale (ESS) total score
Time Frame: Week 12
The ESS consists of 8 items, each scored from 0 to 3. The total score range is from 0-24. Higher scores indicate greater daytime sleepiness; lower scores are better.
Week 12

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Appello Pharmaceuticals, Inc.

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)

February 25, 2026

Primary Completion (Estimated)

September 3, 2027

Study Completion (Estimated)

January 3, 2028

Study Registration Dates

First Submitted

January 29, 2026

First Submitted That Met QC Criteria

February 19, 2026

First Posted (Actual)

February 25, 2026

Study Record Updates

Last Update Posted (Actual)

September 10, 2026

Last Update Submitted That Met QC Criteria

September 8, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • APLO-1201

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

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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