← Trials/Trial dossier/NCT03856359

CompletedPhase 2Results posted

Trial of Rifaximin in Probable Alzheimer's Disease

Pilot, Single Center, Open, Trial of Rifaximin in Probable Alzheimer's Disease

Lead sponsor

Duke University

Asset

Rifaximin

Listed sites

Recruiting sites

Enrollment

actual

Study population

Alzheimer’s disease

Key I/E criteria

•Alzheimer's disease•MMSE 10-23•Study partner/caregiver required

Primary endpoints

•Diarrhea Caused by Clostridium Difficile•ADAS-Cog

Footprint

Where this trial recruits

Site locations as reported to ClinicalTrials.gov. Site count is not enrollment count; per-site enrollment is not available from source.

Identifiers

Registered as

NCT IDNCT03856359

Org study IDPro00093318

Timeline

Milestones

Study first posted2019-02-27actual

Study start2019-04-09actual

Primary completion2020-11-19actual

Study completion2020-11-19actual

Last update posted2021-12-17actual

Results first posted2021-12-17actual

Assets

Drug assets

Rifaximin

Study populations

Who this study enrolls

Alzheimer’s disease

Eligibility

Who can enroll

Minimum age55 Years

Maximum age85 Years

SexAll

Healthy volunteersNot accepted

Inclusion criteria

•· Probable Alzheimer's Disease (National Institute of Neurological Disorders and Stroke (NINDS) criteria), mild to moderate severity

-Ages 55-85; both genders

-Mini Mental State Exam (MMSE) scores 10-23

-Willing and able to comply with all scheduled clinic visits.

-Stable medical health

-Has a family or professional caregiver who has regular contact with subject

-Ability to consent or legal guardian who can consent

-Living at home or in a facility

-On no AD therapies or on stable (2 months) concurrent AD therapies

Exclusion criteria

•Past history of C diff infection

•Assessment, laboratory examination, physical examination or any other medical condition or circumstance making the volunteer unsuitable for participation in the study in the judgment of the study clinicians

•Allergy to Rifaximin

•Antibiotic use or hospitalization in the last 6 months

•Are taking medications that interact with rifaximin and/or pose a safety risk in the judgment of the PI

•Clinically significant abnormal hepatic or renal function

•Uncorrected thyroid or B12 abnormalities

•Participation in another investigational drug trial in the past 30 days

•History of febrile illness within 5 days prior to the study period

•Known Hyperammonemia caused by:

Valproic acid Chemotherapy Lung transplant Bariatric surgery Ureterosigmoidoscopy Hyperalimentation Urinary tract infection Errors of metabolism: urea cycle, enzyme deficiencies, organic acidemias, fatty acid oxidation, amino acid transport defects

Endpoints (40)

What's being measured

Protocol endpoints and posted registry outcome measures, grouped into outcome categories. Composite endpoints show their component event types. Standard codes (LOINC, SNOMED CT) are shown where available.

Coverage by outcome category

Other (unclassified)

Global cognition

Tau biomarkers

Neurodegeneration biomarkers

Safety / tolerability / PK

Global cognition

4 endpoints

Primary/protocol endpoint

Change in ADAS Cog 11 Scores

Time frame:At baseline and at 3 months

ADAS-Cog

change from baseline, improvement

Primary/registry result

Change in ADAS Cog 11 Scores

Time frame:At baseline and at 3 months

ADAS-Cog

change from baseline, improvement

Posted result

Group	Value (mean), score on a scale	Reported bounds
Rifaximinn=10 Participants	30.5	-30.3 - 31

p0.60t-test, 2 sided

Secondary/protocol endpoint

Change in Cognitive Performance on the Mini-Mental State Exam (MMSE)

Time frame:Baseline, 3 months

Mini-Mental State Examination (MMSE)

change from baseline, improvement

Secondary/registry result

Change in Cognitive Performance on the Mini-Mental State Exam (MMSE)

Time frame:Baseline, 3 months

Mini-Mental State Examination (MMSE)

change from baseline, improvement

Posted result

Group	Value (mean), score on a scale	Reported bounds
Rifaximinn=10 Participants	-0.3	--1.8 - 1.2

p0.67t-test, 2 sided

Tau biomarkers

4 endpoints

Secondary/protocol endpoint

Total Tau

Time frame:Baseline, 3 months

change from baseline, improvement

Secondary/protocol endpoint

Phosphorylated Tau

Time frame:at baseline and at 3 months

change from baseline, improvement

Secondary/registry result

Total Tau

Time frame:Baseline, 3 months

change from baseline, improvement

Posted result

Group	Value (number), ng/mL	Reported bounds
Rifaximinn=10 Participants	-0.17	--0.61 - 0.26

p0.38t-test, 2 sided

Secondary/registry result

Phosphorylated Tau

Time frame:at baseline and at 3 months

change from baseline, improvement

Posted result

Group	Value (mean), ng/mL	Reported bounds
Rifaximinn=10 Participants	-0.39	--1.07 - 0.30

p0.23t-test, 2 sided

Neurodegeneration biomarkers

4 endpoints

Secondary/protocol endpoint

Change in Glial Fibrillary Acidic Protein (GFAP)

Time frame:Baseline, 3 months

change from baseline, improvement

Secondary/protocol endpoint

Change in Neurofilament Light (Nfl) Levels

Time frame:Baseline, 3 months

Neurofilament light (NfL)

change from baseline, improvement

Secondary/registry result

Change in Glial Fibrillary Acidic Protein (GFAP)

Time frame:Baseline, 3 months

change from baseline, improvement

Posted result

Group	Value (mean), pg/mL	Reported bounds
Rifaximinn=10 Participants	-39.76	--99.46 - 19.93

p0.17t-test, 2 sided

Secondary/registry result

Change in Neurofilament Light (Nfl) Levels

Time frame:Baseline, 3 months

Neurofilament light (NfL)

change from baseline, improvement

Posted result

Group	Value (mean), ng/L	Reported bounds
Rifaximinn=10 Participants	-4.22	--6.71 - -1.72

p0.004t-test, 2 sided

Safety / tolerability / PK

4 endpoints

Secondary/protocol endpoint

Change in Tolerability as Measured by Number of Adverse Events (AE).

Time frame:Baseline, 3 months, 5 months

change from baseline, event

Secondary/protocol endpoint

Participants With Treatment Emergent Adverse Events as Reported by the Subject That Required a Change in Safety Measures

Time frame:Safety will be measured through adverse events throughout study, at month 3 and by phone call at month 5 (2 months after treatment termination).

change from baseline, event

Secondary/registry result

Change in Tolerability as Measured by Number of Adverse Events (AE).

Time frame:Baseline, 3 months, 5 months

change from baseline, event

Posted result

Group	Value (count_of_participants), Participants	Reported bounds
Rifaximinn=10 Participants	7	-

Secondary/registry result

Participants With Treatment Emergent Adverse Events as Reported by the Subject That Required a Change in Safety Measures

Time frame:Safety will be measured through adverse events throughout study, at month 3 and by phone call at month 5 (2 months after treatment termination).

change from baseline, event

Posted result

Group	Value (number), percentage of participants	Reported bounds
Rifaximinn=10 Participants	0	-

Other (unclassified)

24 endpoints

Primary/protocol endpoint/low confidence

Number of Participants Experiencing Diarrhea Caused by Clostridium Difficile

Time frame:5 months

event count, event

Primary/registry result/low confidence

Number of Participants Experiencing Diarrhea Caused by Clostridium Difficile

Time frame:5 months

event count, event

Posted result

Group	Value (count_of_participants), Participants	Reported bounds
Rifaximinn=10 Participants	5	-

Secondary/protocol endpoint/low confidence

Changes From Baseline in Ammonia Level

Time frame:Baseline, 3 months

change from baseline, improvement

Secondary/protocol endpoint/low confidence

Development of Clostridium Difficile Diarrhea

Time frame:Baseline to 3 months

descriptive

Secondary/protocol endpoint/low confidence

Change in Interleukin 10 (IL-10)

Time frame:Baseline, 3 months

change from baseline, improvement

Secondary/protocol endpoint/low confidence

Changes in Interleukin 13 (IL-13) Following Treatment With Rifaximin

Time frame:Baseline, 3 months

descriptive

Secondary/protocol endpoint/low confidence

Change in Interleukin 1B (IL-1B)

Time frame:Baseline, 3 months

change from baseline, improvement

Secondary/protocol endpoint/low confidence

Change in Interleukin 2 (IL-2)

Time frame:Baseline, 3 months

change from baseline, improvement

Secondary/protocol endpoint/low confidence

Change in Interleukin 4 (IL-4)

Time frame:Baseline, 3 months

change from baseline, improvement

Secondary/protocol endpoint/low confidence

Change in Interleukin 5 (IL-5)

Time frame:Baseline, 3 months

change from baseline, improvement

Secondary/protocol endpoint/low confidence

Change in Interleukin 8 (IL-8)

Time frame:Baseline, 3 months

change from baseline, improvement

Secondary/protocol endpoint/low confidence

Change in Interleukin 6 (IL-6)

Time frame:Baseline, 3 months

change from baseline, improvement

Secondary/protocol endpoint/low confidence

Change in Tumor Necrosis Factor a

Time frame:Baseline, 3 months

change from baseline, improvement

Secondary/registry result/low confidence

Changes From Baseline in Ammonia Level

Time frame:Baseline, 3 months

change from baseline, improvement

Posted result

Group	Value (mean), mg/dL	Reported bounds
Rifaximinn=10 Participants	0.1	--7.06 - 7.25

p0.73t-test, 2 sided

Secondary/registry result/low confidence

Development of Clostridium Difficile Diarrhea

Time frame:Baseline to 3 months

descriptive

Posted result

Group	Value (number), percentage of subjects	Reported bounds
Rifaximinn=10 Participants	0	-

Secondary/registry result/low confidence

Change in Interleukin 10 (IL-10)

Time frame:Baseline, 3 months

change from baseline, improvement

Posted result

Group	Value (mean), pg/mL	Reported bounds
Rifaximinn=10 Participants	00.70	--4.85 - 3.46

p0.7t-test, 2 sided

Secondary/registry result/low confidence

Changes in Interleukin 13 (IL-13) Following Treatment With Rifaximin

Time frame:Baseline, 3 months

descriptive

Posted result

Group	Value (mean), pg/mL	Reported bounds
Rifaximinn=10 Participants	-1.78	--3.9 - 0.33

p0.09t-test, 2 sided

Secondary/registry result/low confidence

Change in Interleukin 1B (IL-1B)

Time frame:Baseline, 3 months

change from baseline, improvement

Posted result

Group	Value (mean), pg/mL	Reported bounds
Rifaximinn=10 Participants	-0.1	--2.06 - 1.87

p0.65t-test, 2 sided

Secondary/registry result/low confidence

Change in Interleukin 2 (IL-2)

Time frame:Baseline, 3 months

change from baseline, improvement

Posted result

Group	Value (mean), pg/mL	Reported bounds
Rifaximinn=10 Participants	-0.33	--0.93 - 0.27

p0.18t-test, 2 sided

Secondary/registry result/low confidence

Change in Interleukin 4 (IL-4)

Time frame:Baseline, 3 months

change from baseline, improvement

Posted result

Group	Value (mean), pg/mL	Reported bounds
Rifaximinn=10 Participants	-17.40	--68.73 - 33.93

p0.44t-test, 2 sided

Secondary/registry result/low confidence

Change in Interleukin 5 (IL-5)

Time frame:Baseline, 3 months

change from baseline, improvement

Posted result

Group	Value (mean), pg/mL	Reported bounds
Rifaximinn=10 Participants	-0.87	--2.34 - 0.60

p0.20t-test, 2 sided

Secondary/registry result/low confidence

Change in Interleukin 8 (IL-8)

Time frame:Baseline, 3 months

change from baseline, improvement

Posted result

Group	Value (mean), pg/mL	Reported bounds
Rifaximinn=10 Participants	-1.31	--5.81 - 3.20

p0.53t-test, 2 sided

Secondary/registry result/low confidence

Change in Interleukin 6 (IL-6)

Time frame:Baseline, 3 months

change from baseline, improvement

Posted result

Group	Value (mean), pg/mL	Reported bounds
Rifaximinn=10 Participants	-1.62	--3.39 - 0.15

p0.07t-test, 2 sided

Secondary/registry result/low confidence

Change in Tumor Necrosis Factor a

Time frame:Baseline, 3 months

change from baseline, improvement

Posted result

Group	Value (mean), pg/mL	Reported bounds
Rifaximinn=10 Participants	-0.46	--1.55 - 0.64

p0.36t-test, 2 sided

Provenance

Sources

Trial identity, design, statusClinicalTrials.gov API v2

Snapshot dateJuly 21, 2026

Endpoint classificationDelfa ADRD endpoint taxonomy

Results tableClinicalTrials.gov results section

Trial facts come from public ClinicalTrials.gov records. Endpoint categories are Delfa's classification of those records, not a ClinicalTrials.gov field. All figures reflect the July 21, 2026 snapshot.