Microbiota Intervention to Change the Response of Parkinson's Disease

Study Overview
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Brief Summary
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The clinical phenotype of Parkinson's disease (PD) is quite variable, as is the response to and side effects from medications. While many patients respond to carbidopa/levodopa early on, motor fluctuations and dyskinesias can become a problem as the condition progresses, causing significant impairment in function and quality of life. The gut microbiome is of increasing interest in PD, potentially contributing to pathophysiology and clinical phenotype. Furthermore, gut bacteria are capable of metabolizing levodopa, which may decrease its ability to reach the central nervous system and could explain the variable effect seen clinically. Altering the population of drug-metabolizing bacteria could improve the clinical symptoms of PD and the benefit seen with medications. The investigators hypothesize that the gut microbiome in people with PD correlates with their phenotypic characteristics, which can be improved with targeting the microbiome through dietary or therapeutic interventions. The investigators propose a two-part clinical trial. First, a cross-sectional analysis will correlate the microbiome profile with (a) the clinical phenotype of PD and (b) medication response. Second, a randomized, controlled trial, will evaluate the effect of microbiome manipulation on clinical phenotype and medication response. The investigators plan to reduce the level of bacteria through antibiotic use, resetting the potentially disadvantageous microbiome population. Outcomes will include changes in clinical symptoms, alterations in the the microbiome, and changes in serum markers of inflammation. This thorough characterization will broaden our understanding of the gut-brain axis significantly in PD in clinically relevant ways that have yet to be explored.

Official Title
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Microbiota Intervention to Change the Response of Parkinson's Disease

Conditions
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Parkinson Disease

Intervention / Treatment
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* Drug: Rifaximin
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Parkinson's disease Stable on levodopa therapy with fluctuations Exclusion Criteria: Chronic gastrointestinal disease Recent antibiotic or probiotic therapy Pregnant Immunocompromised

Ages Eligible for Study
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Minimum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intervention<br>Rifaximin | Drug: Rifaximin<br>* Rifaximin 550mg orally<br>|
| Placebo Comparator: Placebo<br>Matching placebo | Other: Placebo<br>* Placebo control<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| MDS-UPDRS Part III | The Movement Disorders Society - Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is a validated scale that quantifies many of the symptoms and signs of Parkinson's disease. Part III in particular focuses on the motor symptoms of Parkinson's disease through a neurologic exam. The exam is often performed when medications are held for 8-12 hours (the OFF state) and again when medications are given and providing therapeutic benefit (the ON state), and the difference between scores is calculated. The scale goes from a minimum of 0 to a maximum of 132. There is no specific cutoff, but a higher score indicates a higher severity of symptoms. The trial will examine the change in the MDS-UPDRS Part III both OFF and ON medication after the intervention. | Two weeks | 
| Percent of OFF time according to home motor diaries | Patients with Parkinson's disease often have times where levodopa is providing therapeutic benefit and times when it is not. OFF time indicates the times of day where levodopa therapy is not providing therapeutic benefit. An outcome of the trial will be the change in medication OFF time that the participant experiences at home, according to motor diaries. | Two weeks |