Microbiota Intervention to Change the Response of Parkinson's Disease

NCT ID: NCT03575195

Last Updated: 2025-09-04

Basic Information

• Recruitment Status: SUSPENDED
• Clinical Phase: PHASE1/PHASE2
• Total Enrollment: 86 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2019-07-15
• Study Completion Date: 2026-08-31

Brief Summary

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.

Conditions

Parkinson Disease

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: QUADRUPLE

Study Groups

Intervention

Rifaximin

Group Type: EXPERIMENTAL

Rifaximin

Intervention Type: DRUG

Rifaximin 550mg orally

Placebo

Matching placebo

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: OTHER

Placebo control

Interventions

Rifaximin

Rifaximin 550mg orally

Intervention Type: DRUG

Placebo

Placebo control

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Parkinson's disease
• Stable on levodopa therapy with fluctuations

Exclusion Criteria

• Chronic gastrointestinal disease
• Recent antibiotic or probiotic therapy
• Pregnant
• Immunocompromised

• Minimum Eligible Age: 30 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Nova Southeastern University

OTHER

Sponsor Role: collaborator

Gateway Institute for Brain Research

INDUSTRY

Sponsor Role: collaborator

University of California, San Francisco

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Caroline Tanner, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

University of California, San Francisco

Locations

University of California San Francisco

San Francisco, California, United States

Countries

United States

Other Identifiers

17-22841

Identifier Type: -

Identifier Source: org_study_id