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NCT07567794Recruiting

GBPDC: Gut-Brain in PD Consortium Master Protocol

Consortium for Gut-Brain Communication in Parkinson's Disease Master Protocol

Source: ClinicalTrials.gov · Last updated 25 Sept 2026

Brief summary (registry, in English)

The purpose of this research study is to identify the role that the gut-brain axis, the group of nerves that connect the brain and gut, plays in Parkinson's disease (PD). The National Institute of Diabetes and Digestive and Kidney Diseases is sponsoring this research study. During this study, specific groups of participants, also known as "cohorts", will be identified based on the severity of their PD. There will also be a cohort enrolling participants who do not have Parkinson's and a cohort enrolling participants that are at risk for developing PD. Each of these cohorts will be compared to the others to assess the differences in the gut-brain connection. Participants in this study will: * meet with a medical provider * answer questionnaires * give samples of blood, stool, and saliva * have X-rays taken while swallowing different foods (swallowing study) * have X-rays taken to see how long it takes markers to move through their colon (colon transit study) * have a flexible sigmoidoscopy, where a doctor looks inside the lower part of the colon and takes small tissue samples (biopsies) from the mucosa (lining) * have samples taken of their skin * have an anorectal manometry and a balloon expulsion test, where a small tube and balloon are placed in the rectum to measure muscle function. Participation in the study will last up to 24 months (2 years).

Status (registry)
Recruiting
Study type
Observational
Enrollment
250 (estimated)
First submitted
29 Apr 2026
Start date
Jul 2026
Primary completion date
Dec 2028
Lead sponsor
Duke University
NCT number
NCT07567794

What you commit to

  • Study type: Observational
  • Planned participants: 250
  • From Jul 2026 to the primary completion date, Dec 2028
  • 7 sites in 1 country
  • Visits and tests: ask the trial team, the registry does not list them

Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.

Who cannot take part

Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.

Prior treatment

  • Currently taking anticoagulants that are deemed exclusionary by the investigator for risk of bleeding with sigmoidoscopy procedure
  • Suicidality, defined as active suicidal thoughts or ideation within 6 months before Screening or at Baseline, defined as answering yes to items 4 or 5 on the Columbia-Suicide Severity Rating Scale (C-SSRS), or history of suicide attempt in previous 2 years, or, in the Investigator's opinion, at serious risk of suicide
  • History of Covid 19 (SARS-CoV-2) infection within 6 weeks prior to screening.
  • Either ongoing or current participation in another clinical trial with an investigational agent and have taken at least one dose of study medication, unless unblinded on placebo, within 4 weeks prior to the start of screening, or five half-lives of the investigational drug, whichever is greater. The end of a previous investigational trial is the date the last dose of an investigational agent was taken. Participation in other research studies (e.g., observational studies) may be acceptable throughout this study.
  • Regular use of medication that impacts the intestinal barrier (e.g., NSAID more than 3 times weekly)

Other illness

  • Clinically significant cognitive impairment with a Montreal Cognitive Assessment (MOCA) score \<22
  • Has cancer or has had a malignant tumor within the past 5 years. (Participants with stable untreated prostate cancer or treated/removed cutaneous carcinomas are not excluded.)
  • Any medical condition or systemic disease that, in the Investigator's opinion, may either put the participant at risk because of participation in the study, influence the results or proposed analyses, or impair the participant's ability to fully participate in the study
  • History of alcohol or substance abuse or dependence within the past 2 years (DSM IV criteria)
  • Participants with unresolved symptoms of Covid 19 infection or ongoing cognitive or other deficits attributable to post-Covid 19 that may affect participant safety or interfere with cognitive assessments based on the Investigator's clinical judgment
  • History of GI surgery. (However, patients with appendicectomy, hemorrhoid surgery, and cholecystectomy will be eligible to participate).
  • Has a history of Crohn's disease, ulcerative colitis, and/or other types of colitis (microscopic, lymphocytic, or collagenous colitis). Confirmed diagnosis of inflammatory bowel disease (IBD) and/or, active or uncontrolled IBD symptoms such as diarrhea, bleeding, or severe stomach pain. Treatment for IBD in the past 6 months with medicines such as steroids, biologics, or strong immune-suppressing drugs. Surgery to remove part of the bowel due to IBD. Other long-term gut diseases that cause inflammation, such as celiac disease.

Lab values

  • Laboratory Values:
    • Hemoglobin (Hgb) \<10
    • Platelets \<70,000
    • Alanine Transaminase (ALT) or Aspartate Aminotransferase (AST) \> 2 1/2 times upper limit of normal (ULN)
    • Moderate or severe renal disease with an estimated glomerular filtration rate (eGFR) \<60 mL/min/BSA \[body surface area\]) calculated using the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation, or moderate or severe hepatic impairment (alkaline phosphatase \[ALP\] \>2.0 times the ULN and/or total bilirubin \>2.0 times the ULN)
    • Significantly above the normal range for PT/INR/PTT
  • Clinical or laboratory findings consistent with another primary neurodegenerative disease or cognitive disorder other than PD, including but not limited to, frontotemporal lobar disease, Huntington's disease, progressive supranuclear palsy, multisystem atrophy, Creutzfeld-Jakob- Disease, Down's syndrome, cortico-basal degeneration, dementia with Lewy Bodies, Alzheimer's disease, amyotrophic lateral sclerosis, seizure disorder, stroke, or other infectious, metabolic, or systemic disease affecting the central nervous system including, but not limited to, syphilis, present hypothyroidism, present or unaddressed/treated vitamin B12 deficiency, or other screening laboratory abnormalities

Other

  • Diagnosis of secondary or atypical parkinsonism
  • Body mass index (BMI) \>35 kg/m2 or body weight \<50 kg
  • Participant is currently pregnant, breastfeeding, and/or lactating

Who the study is looking for

  • Aged ≥21 years old and ≤80 years old
  • Clinical diagnosis of PD as defined by Movement Disorder Society (MDS) PD Criteria
  • Adequate visual, hearing, cognitive, and physical ability
  • Willingness and ability to comply with scheduled visits, laboratory tests, and other study procedures. Because longitudinal participation is important to the scientific goals of the program, a "best estimate" of interest, commitment, and geographic feasibility for three years will be documented by the enrolling investigator after interview with the potential enrollee
  • Aged ≥21 years old and ≤80 years old
  • No known or diagnosed neurodegenerative disease
  • Willingness and ability to comply with scheduled visits, laboratory tests, and other study procedures
  • Resides within the same household as person with PD
  • Aged ≥21 years old and ≤80 years old
  • Prodromal characteristics are defined by the MDS Research Criteria for PD and include either polysomnography (PSG)-confirmed rapid eye movement sleep behavior disorder (RBD) or possible RBD (questionnaire-based), with hyposmia as defined by the University of Pennsylvania Smell Identification Test (UPSIT) ≤ 15th percentile.

Age in the registry: 21 years to 80 years · Sex: All · Accepts healthy volunteers

Full criteria on ClinicalTrials.gov

Sites (7)

Sites in registry order. Pick your city on the disease page to sort them by distance.

SiteCityCountrySite status
Massachusetts General Hospital
Coordinator of this site? Confirm its status
BostonUnited StatesRecruiting
Medical University of South Carolina
Coordinator of this site? Confirm its status
CharlestonUnited StatesNot yet recruiting
University of Chicago
Coordinator of this site? Confirm its status
ChicagoUnited StatesNot yet recruiting
RUSH University
Coordinator of this site? Confirm its status
ChicagoUnited StatesRecruiting
Columbia University
Coordinator of this site? Confirm its status
New YorkUnited StatesNot yet recruiting
Mayo Clinic
Coordinator of this site? Confirm its status
RochesterUnited StatesRecruiting
Stanford University
Coordinator of this site? Confirm its status
StanfordUnited StatesRecruiting

This page is information, not medical advice. Discuss any trial with your doctor.