Crofelemer for Functional Diarrhea

March 6, 2026 updated by: Judy Nee, Beth Israel Deaconess Medical Center
The primary objectives of this study are to evaluate the clinical response of patients with diarrhea to crofelemer relative to placebo and evaluate the overall safety and tolerability of crofelemer in the treatment of diarrhea.

Study Overview

Status

Terminated

Conditions

Intervention / Treatment

Detailed Description

Crofelemer is a potent antisecretory agent and has promising therapeutic properties for functional diarrhea patients. Crofelemer is an active compound extracted from the latex of the Western South American plant Croton lechleri. The latex has been used for medicinal purposes for centuries by indigenous peoples, with its active properties attributable to the crofelemer compound (11). Crofelemer has an inhibitory effect on cyclic AMP-mediated secretion of chloride ions in T84 and Caco-2 epithelial cells, resulting in antisecretory effects in the colon that may alleviate diarrhea and related symptoms (12). Crofelemer has been shown to improve traveler's diarrhea and HIV-associated diarrhea (13,14). It's applicability to symptoms of functional diarrhea is still unclear.

In a Phase II randomized trial, Mangel & Chaturvedi observed the effects of crofelemer in the setting of Inflammatory Bowel Syndrome-D (15). While they did not meet the primary endpoint of altering stool consistency in IBS-D patients, they did find upon further analysis that crofelemer significantly reduced the number of pain- and discomfort-free days in female patients with IBS-D. This study warrants further investigation of the effects of crofelemer in treating symptoms of functional diarrhea.

Study Type

Interventional

Enrollment (Actual)

17

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Massachusetts
      • Boston, Massachusetts, United States, 02215
        • Beth Israel Deaconess Medical Center

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

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Patient is a man or woman aged 18 to 65 years, inclusive, at Screening.
  2. Patient has functional diarrhea defined by the Rome IV criteria as loose (mushy) or watery stools ≥25% and hard or lumpy stools <25% of bowel movements
  3. Patient has had a colonoscopy performed:

    1. Within 10 years prior to Prescreening if patient is at least 50 years of age (alternatively, a flexible sigmoidoscopy, double contrast barium enema, or CT colonography within the past 5 years is acceptable [see recommendations of the American Cancer Society])
    2. Since the onset (if applicable) of any of the following alarm features for patients of any age (see Spiller and Thompson, 2010 - i.e. Patient has documented weight loss within the past 6 months; Patient has nocturnal symptoms; Patient has a familial history of colon cancer; or patient has blood mixed with their stool (excluding any blood from hemorrhoids).
  4. Patient has an average daily stool consistency score (BSS) of ≥5.5 on days without the use of an anti-diarrheal and at least 3 days with a BSS score ≥5 on a 1 to 7 scale over the week prior to randomization.
  5. Patient has completed the daily diary on at least 6 of the 7 days during the week prior to randomization AND at least 11 of the 14 days during the 2 weeks prior to randomization.
  6. Patient has not used loperamide rescue medication more than 4 days during the screening period.
  7. Patient is not planning to change his/her usual diet and lifestyle during the course of the study.
  8. Patient is willing to be compliant with study procedures including completing the daily diary during the screening period and throughout the study.
  9. Patient must sign an informed consent document before the initiation of any study-related procedures indicating that he or she understands the purpose of and procedures required for the study and is willing to participate in the study.

Exclusion Criteria:

  1. Patient has a history of inflammatory or immune-mediated GI disorders including inflammatory bowel disease (ie, Crohn's disease, ulcerative colitis, microscopic colitis) and celiac disease.
  2. Patient has a predominant symptom of abdominal pain.
  3. Patient has a history of diverticulitis within 3 months prior to screening. Patients with a history of diverticulosis are candidates for the study.
  4. Patient has a history of intestinal obstruction, stricture, toxic megacolon, GI perforation, fecal impaction, gastric banding, bariatric surgery, adhesions, ischemic colitis, or impaired intestinal circulation (eg, aortoiliac disease).
  5. Patient has any of the following surgical history:

    1. Any abdominal surgery within the 3 months prior to screening; or
    2. Patient has a history of major gastric, hepatic, pancreatic, or intestinal surgery (appendectomy, cholecystectomy, hemorrhoidectomy, or polypectomy greater than 3 months are allowed). For the purposes of this study, laparoscopic surgeries without complication are considered minor and non-exclusionary, provided the condition for which the surgery was performed was not exclusionary.
  6. Patient has an unstable renal, hepatic, metabolic, or hematologic condition.
  7. Patient has a history of human immunodeficiency virus infection.
  8. Patient has a history of DSM(Diagnostic and Statistical Manual)-IV-TR-defined substance dependency, excluding nicotine and caffeine, within 2 years prior to Prescreening.
  9. Patient has a history of alcohol abuse as defined by DSM-IV-TR, binge drinking as defined by the National Institutes on Alcohol Abuse and Alcoholism, or any medical treatment for alcohol-related co-morbidities, within 5 years prior to Prescreening. Recovered alcoholics who have not consumed alcohol over the 5 years prior to Prescreening are candidates for the study.
  10. Patient has current (within 14 days of randomization) or expected use of any narcotic or opioid containing agents, tramadol
  11. Patient is unable to swallow solid, oral dosage forms whole with the aid of liquid (patients may not chew, divide, dissolve, or crush the study drug).
  12. Patient has received an investigational drug or used an investigational medical device within 30 days prior to randomization.
  13. Patient has a known pregnancy or is breastfeeding.

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: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: crofelemer
125mg bid
Crofelemer
Other Names:
  • mytesi
Placebo Comparator: placebo
bid
placebo

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Consistency of Stool at Week 4
Time Frame: week 4
Average stool consistency score on the scale from 1 to 7 (from Bristol stool form scale (BSFS)). This rates the stool consistency by type from 1-7. BSFS 1 indicates hard stool consistent with constipation, whereas BSFS of 7 indicates loose, watery stool consistent with diarrhea. Therefore, in this study, a higher score indicates more diarrhea/worse outcome
week 4

Collaborators and Investigators

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

Investigators

  • Principal Investigator: Anthony Lembo, MD, Beth Israel Deaconess Medical Center

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)

August 20, 2020

Primary Completion (Actual)

September 23, 2022

Study Completion (Actual)

September 23, 2022

Study Registration Dates

First Submitted

July 20, 2020

First Submitted That Met QC Criteria

July 20, 2020

First Posted (Actual)

July 24, 2020

Study Record Updates

Last Update Posted (Actual)

March 10, 2026

Last Update Submitted That Met QC Criteria

March 6, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • 2020P-000464

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

product manufactured in and exported from the U.S.

Yes

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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