Study of the Research Medicine CIN-103 in Adults With Irritable Bowel Syndrome With Predominant Diarrhea (IBS-D).

A Phase 2, Randomized, Double-Blind, Placebo-Controlled, Multicenter, Parallel-Group Study to Evaluate the Efficacy, Safety, and Tolerability of CIN-103 in Adults With Irritable Bowel Syndrome With Predominant Diarrhea (IBS-D)

The goal of this clinical trial is to evaluate if the study drug, CIN-103, can help reduce the symptoms associated with irritable bowel syndrome with predominant diarrhea (IBS-D) in adult patients. The main questions it aims to answer are:

• To evaluate the efficacy of CIN-103 on symptoms of IBS-D when given to patients with IBS-D compared to a placebo.
• To evaluate the safety and tolerability of CIN-103 when given to patients with IBS-D compared to a placebo

Participants will attend the following visits:

• Screening Period (1 Visit)

• Baseline Period (1 Visit)

  • Will complete daily diary and other Patient Reported Outcomes (PROs) as described in the protocol to assess eligibility for continued participation.

• 12-Week Treatment Period (5 Visits)

  • Study drug taken twice daily by mouth.
  • Will complete daily diaries and other PROs as described in the protocol.
• Follow- Up Period (1 Visit)

Researchers will compare CIN-103 Dose 1, CIN-103 Dose 2, and placebo, to evaluate the clinical response to multiple dose strengths of CIN-103 relative to placebo on abdominal pain and stool consistency along with safety and tolerability.

Study Overview

• Status: Terminated
• Conditions: Irritable Bowel Syndrome With Diarrhea
• Intervention / Treatment: Drug: CIN-103; Drug: Placebo

• Study Type: Interventional
• Enrollment (Actual): 421
• Phase: Phase 2

Contacts and Locations

Study Locations

• United States
  • Alabama
    • Dothan, Alabama, United States, 36305
      • Digestive Health Specialists - Dothan
    • Huntsville, Alabama, United States, 35801
      • Clinical Research Associates, LLC
  • Arizona
    • Phoenix, Arizona, United States, 85018
      • Elite Clinical Studies LLC
    • Sun City, Arizona, United States, 85351
      • GI Alliance - Sun City
  • Arkansas
    • Little Rock, Arkansas, United States, 72212
      • Applied Research Center of Arkansas
  • California
    • Garden Grove, California, United States, 92840
      • Paragon Rx Clinical, Inc. - Garden Grove
    • Lancaster, California, United States, 93534
      • Gastro Care Institute- lancaster
    • San Diego, California, United States, 92123
      • Medical Associates Research Group
  • Florida
    • Cape Coral, Florida, United States, 33909
      • American Family Research Group
    • Doral, Florida, United States, 33126
      • USA and International Research Inc.
    • Miami, Florida, United States, 33183
      • International Research Associates LLC
    • Palmetto Bay, Florida, United States, 33157
      • Innovation Medical Research Center
  • Georgia
    • Savannah, Georgia, United States, 31406
      • Velocity Clinical Research,, Savannah
  • Illinois
    • Oak Lawn, Illinois, United States, 60453
      • Southwest Gastroenterology
  • Louisiana
    • Mandeville, Louisiana, United States, 70471
      • DelRicht Research
    • Marrero, Louisiana, United States, 70072
      • Tandem Clinical Research GI LLC
    • Metairie, Louisiana, United States, 70006
      • Tandem Clinical Research GI LLC
    • New Orleans, Louisiana, United States, 70115
      • DelRicht Research
    • West Monroe, Louisiana, United States, 71291
      • Delta Research Partners, LLC
  • Maryland
    • Rockville, Maryland, United States, 20852
      • DelRicht Research of Bethesda Clinical Trials
  • Missouri
    • Weldon Spring, Missouri, United States, 63304
      • St. Charles Clinical Research
  • Nebraska
    • Omaha, Nebraska, United States, 68114
      • Quality Clinical Research, Inc
  • Nevada
    • Las Vegas, Nevada, United States, 89113
      • Las Vegas Medical Research
    • Las Vegas, Nevada, United States, 89128
      • Digestive Disease Specialists
    • Reno, Nevada, United States, 89511
      • Advanced Research Institute - Reno
  • New Jersey
    • Somers Point, New Jersey, United States, 08244
      • Allied Digestive Health Clinical Research Organization
    • Somers Point, New Jersey, United States, 08244
      • Allied Digestive Health-Jersey Shore Gastroenterology - Point Commons
  • New Mexico
    • Albuquerque, New Mexico, United States, 87102
      • Albuquerque Clinical Trials, Inc
  • New York
    • Carmel Hamlet, New York, United States, 10512
      • Westchester Putnam Gastro
    • New York, New York, United States, 10128
      • IMA Clinical Research PC and Affiliates- New York, NY
    • New York, New York, United States, 11235
      • NY Scientific
  • North Carolina
    • Charlotte, North Carolina, United States, 28204
      • Atrium Health - Center for Gastroenterology and Hepatology MMP
    • High Point, North Carolina, United States, 27262
      • Peters Medical Research
    • Mount Airy, North Carolina, United States, 27030
      • Ima Clinical Research
  • Ohio
    • Cleveland, Ohio, United States, 44195
      • Cleveland Clinic
    • Columbus, Ohio, United States, 43215
      • Remington Davis, Inc.
    • Mentor, Ohio, United States, 44060
      • Great Lakes Gastroenterology Research LLC
    • Westlake, Ohio, United States, 44145
      • Northshore Gastroenterology Research, LLC
  • Oklahoma
    • Tulsa, Oklahoma, United States, 74104
      • Options Health Research LLC
  • Pennsylvania
    • Harrisburg, Pennsylvania, United States, 17110
      • Susquehanna Research Group, LLC
  • South Carolina
    • Charleston, South Carolina, United States, 29407
      • DelRicht Research of Charleston Clinical Trials
    • Summerville, South Carolina, United States, 29485
      • Palmetto Clinical Research
  • Tennessee
    • Chattanooga, Tennessee, United States, 37404
      • Galen Medical Group - Downtown Gastroenterology Location
    • Kingsport, Tennessee, United States, 37663
      • Tri-Cities Gastroenterology
    • Union City, Tennessee, United States, 38261
      • Advanced Gastroenterology
  • Texas
    • Bellaire, Texas, United States, 77401
      • The University of Texas Health Science Center at Houston
    • Houston, Texas, United States, 77090
      • Care and Cure Clinic
    • Houston, Texas, United States, 77074
      • The Clinical Trials Network LLC
    • Pharr, Texas, United States, 78577
      • GLRI - McAllen Research
    • San Antonio, Texas, United States, 78209
      • Quality Research Inc
    • San Antonio, Texas, United States, 78229
      • Gastroenterology Research of San Antonio
  • Utah
    • Ogden, Utah, United States, 84405
      • Advanced Research Institute
  • Washington
    • Tacoma, Washington, United States, 98405
      • GI Alliance - Washington Gastroenterology

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

• Inclusion Criteria:

  1. Are adult male and female subjects ≥ 18 years of age;
  2. Have a body mass index between 18 and 45 kg/m2, inclusive at Screening;

  3. Meet Rome IV Criteria for IBS-D by subject self-report of recurrent abdominal pain that is associated with ≥ 2 of the following over the last ≥ 6 months, with frequency of at least 1 day per week over the last 3 months (on average) before enrollment:

     1. Related to defecation;
     2. Associated with a change in frequency of stool; and/or
     3. Associated with a change in form (appearance of stool).
  4. Based on Investigator interview of subject's symptoms over the last 3 months, have ≥ 25% of bowel movements (BMs) with Bristol Stool Scale (BSS) Type 6 or 7 (loose or watery stools) and < 25% of BMs with BSS Type 1 or 2 (lumpy or hard stools) per the Rome IV Criteria for IBS-D;
  5. In the opinion of the Investigator, are on a stable diet for ≥ 4 weeks prior to Screening and are not planning to change lifestyle, exercise, and/or diet that may impact symptoms of IBS-D during study participation;
  6. Have a fecal calprotectin ≤ 100 mcg/g at the Screening Visit or Visit 2; Note: A single normal test result is adequate for study eligibility. If subjects are rescreened within 12 months, there is no need for repeat fecal calprotectin sample collection and testing. However, subjects who fail screening due to a fecal calprotectin level > 100 mcg/g are not eligible for re-screening. Note: Repeat Fecal calprotectin may be considered with prior Sponsor approval.
  7. Have a serum tTG-IgA (tissue transglutaminase immunoglobulin A) ≤ 4.99 FLU (fluorescent light units) at the Screening Visit;

  8. Have undergone a colonoscopy examination within the designated time interval prior to randomization, if they meet any of the following criteria. Note: A negative Cologuard® test result is an acceptable alternative to colonoscopy for subjects ≥ 45 years and at average risk for colon cancer.

     1. Average risk, based on US Preventive Services Task Force Recommendation Statement for screening of colorectal cancer, with age ≥ 45 years (colonoscopy within 10 years or negative test results on Cologuard within 3 years);
     2. Personal history of completely removed adenomatous colorectal polyps (colonoscopy within 5 years for polyps > 1 cm, within 10 years for polyps < 1 cm);
     3. History of colorectal cancer or adenomatous polyps in a first-degree relative before age 60 (colonoscopy within 5 years); or
     4. History of colorectal cancer or adenomatous polyps in ≥ 2 first-degree relatives at any age, or family history of hereditary colorectal cancer or polyposis (colonoscopy within 5 years).

• Exclusion Criteria:

  1. Have a diagnosis or suspected diagnosis of non-diarrhea predominant IBS (eg, IBS with a subtype of constipation, IBS with mixed or alternating bowel habits, un-subtyped IBS) or functional constipation by the Rome IV Criteria;

  2. Non-infectious chronic lower gastrointestinal conditions including a history of or current inflammatory bowel disease (ie, Crohn's disease, ulcerative colitis, indeterminate colitis), recurrent diverticulitis, microscopic colitis, lymphocytic colitis, celiac disease, non-celiac gluten sensitivity and non-compliant on a gluten-free diet, untreated lactose intolerance, carcinoid syndrome, Lynch syndrome, or familial polyposis, intestinal obstruction, stricture, toxic megacolon, solitary rectal ulcer syndrome, GI perforation, intra-abdominal or pelvic adhesions, ischemic colitis, radiation proctitis, chronic enteritis, non-infectious colitis, or impaired intestinal circulation (eg, aortoiliac disease);

     Note: Lactose intolerance and non-celiac gluten sensitivity will not exclude a subject from participation if the Investigator documents that the subject is compliant on a special diet (lactose-free diet or gluten-free diet, respectively) and/or for lactose intolerance is successfully treated with commercial lactase supplement(s).

  3. Infectious lower gastrointestinal conditions requiring antibiotics or microbiome therapy; any microbiologically documented acute lower gastrointestinal colitis or enteritis requiring antibiotic treatment including successfully treated Clostridioides difficile colitis within 3 months prior to Screening, or a history of recurrent C. difficile colitis at any time in the past;
  4. Have a known family history of inflammatory bowel disease in at least 1 first-degree relative;
  5. Have a known history of a pelvic floor disorder associated with constipation (unless successful treatment has been documented by a normal balloon expulsion test or anorectal manometry), refractory constipation not responsive to standard medical therapy, fecal impaction that required hospitalization, cathartic colon, and/or active proctological condition;
  6. Have a history of or current non-IBS chronic condition(s) with ongoing symptoms associated with abdominal pain or GI discomfort (eg, gastroparesis, functional dyspepsia, uncontrolled gastroesophageal reflux disease, polycystic kidney disease, ovarian cysts, urological pain, or endometriosis);
  7. Have a history of or current clinically significant arrhythmias as judged by the Investigator, including ventricular tachycardia, ventricular fibrillation, and Torsades de pointes. Subjects with any abnormal electrocardiogram (ECG) not considered clinically significant by the Investigator are not excluded;

  8. Have current or a history of diverticulitis, heme positive stool, or unexplained GI bleeding within 3 months prior to Screening.

     Note: Surgically repaired diverticulitis > 3 months prior to Screening is permitted.

  9. Have a history of surgical resection of the stomach, small, or large intestine;

  10. Have had any major abdominal surgery within the 3 months prior to Screening;

      Note: Permitted procedures are uncomplicated appendectomy, cholecystectomy, and resection of benign polyps within the 3 months prior to Screening. Subjects who had an appendectomy that was associated with any related complications or sequelae are eligible if the procedure was performed at least 6 months prior to Screening.

  11. Are currently undergoing or planning to initiate treatment with weight loss medication during study participation or prior weight loss surgery (eg, gastric bypass surgery, gastric banding);
  12. Have a planned invasive elective surgery during the period of anticipated study participation from the time of informed consent through the last study visit;

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: CIN-103 BID Dose 1; CIN-103 Dose 1, administered as 2 x CIN-103 capsules and 2 x matching placebo per dose. Two doses per day.	Drug: CIN-103; CIN-103 BID
Experimental: CIN-103 BID Dose 2; CIN-103 Dose 2, administered as 4 x CIN-103 capsules per dose. Two doses per day.	Drug: CIN-103; CIN-103 BID
Placebo Comparator: Placebo for CIN-103 BID; Placebo for CIN-103, administered as 4 x matching placebo capsules per dose. Two doses per day.	Drug: Placebo; Placebo for CIN-103 BID

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Occurrence of meeting Study Composite Responder status for an adult subject with IBS-D.	A subject is defined as a Study Composite Responder if he or she meets the Daily Composite Responder criteria for at least 50% of days with diary entry during the 12-week Double-Blind Treatment Period. A subject is defined as a Daily Composite Responder if he or she meets both the pain intensity and stool consistency criteria as follows: Improvement in the mean daily worst abdominal pain (WAP) score by ≥ 30% compared to the mean daily WAP score from the Baseline Period (the average of the daily measurements over the 14 days prior to randomization); AND; Improvement in stool consistency based on the Bristol Stool Scale (BSS) score < 5 or the absence of a bowel movement (BM) over the past 24 hours. Note: If a subject did not have a BM, an improvement of at least 30% in the WAP score is sufficient for a response on that day. The proportion of subjects with a primary outcome within each dose of CIN-103 will be compared to the proportion of subjects in the placebo arm.	12 weeks of Double Blind Treatment Period

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The occurrence of meeting Weekly Composite Responder status		12-week of Double-Blind Treatment Period
The occurrence of meeting Weekly Composite Responder status over 4-weekly intervals (1 to 4, 5 to 8, and 9 to 12 weeks).	A subject is defined as a Weekly Composite Responder if he or she meets both abdominal pain and stool consistency criteria as follows: An Abdominal Pain Intensity Weekly Responder is defined as a subject who experiences a decrease in the weekly average of WAP in the past 24 hours score of at least 30% compared with Baseline; AND A Stool Consistency Weekly Responder is defined as a subject who experiences a 50% or greater reduction in the number of days per week with at least 1 stool that has a consistency of Type 6 or 7 compared with Baseline.	12 weeks of Double Blind Treatment Period
The change in a composite of the daily mean and weekly mean of daily WAP score and stool consistency score as compared to Baseline	The subject-reported WAP in the past 24 hours will be recorded on an 11-point (ie, 0 to 10) numeric rating scale, where 0 corresponds to no pain and 10 corresponds to worst imaginable pain. The stool consistency will be measured using the Bristol Stool Score, based on a 1 to 7 scale where 1 corresponds to a hard stool and 7 corresponds to watery diarrhea.	12-week of Double-Blind Treatment Period
The change in daily mean and weekly mean number of BMs per day compared to Baseline		12-week of Double-Blind Treatment Period
The occurrence of meeting Stool Consistency Responder status	A participant is considered a Stool Consistency Responder if there is an improvement in stool consistency based on the BSS score < 5 or the absence of a bowel movement over the past 24 hours.	12-week of Double-Blind Treatment Period
The change in the daily mean and weekly mean of stool consistency measured with the Bristol Stool Scale (BSS) as compared to Baseline	The subject-reported BSS consistency score is based on a 1 to 7 scale where 1 corresponds to a hard stool and 7 corresponds to watery diarrhea.	12-week of Double-Blind Treatment Period
The occurrence of meeting Pain Responder status	A participant is considered a Pain Responder if there is an improvement in the mean daily WAP score by ≥ 30% compared to the mean daily WAP score from the Baseline Period (the average of the daily measurements over the 14 days prior to randomization).	12-week of Double-Blind Treatment Period
The change in the daily mean and weekly mean of daily WAP as compared to Baseline		12-week of Double-Blind Treatment Period
The change in the daily mean and weekly mean of daily abdominal bloating score as compared to Baseline.	The subject-reported abdominal bloating in the past 24 hours will be recorded on an 11-point (ie, 0 to 10) numeric rating scale, where 0 corresponds to no bloating and 10 corresponds to worst imaginable bloating.	12-week of Double-Blind Treatment Period
Incidence of clinically significant changes, in the Investigator's opinion, in vital signs, physical examinations, ECGs, and clinical laboratory evaluations.	Including standard safety chemistry panel, hematology, coagulation, lipids, and urinalysis.	Through study completion, up to 19 weeks.
Occurrence of Treatment-Emergent Adverse Events (TEAEs).		Through study completion, up to 19 weeks.
Occurrence of treatment-emergent serious adverse events.		Through study completion, up to 19 weeks.
Occurrence of TEAEs leading to premature discontinuation of the study drug.		Through study completion, up to 19 weeks.
Percentage of post-randomization days with symptom of urgency present ("Yes")	The severity of bowel urgency will be captured on a numeric rating scale from 0 (no urgency) to 10 (worst possible urgency). Using this scale, bowel urgency will also be captured as not present "No" (score 0) or present "Yes" (score 1 to 10).	12-week of Double-Blind Treatment Period
The change in the daily mean and weekly mean of daily urgency score compared to Baseline.	Daily urgency score is measured on a numeric rating scale from 0 (no urgency) to 10 (worst possible urgency).	12-week of Double-Blind Treatment Period
The change in daily mean and weekly mean number of fecal incontinence episodes compared to Baseline	Subjects will receive daily automatic reminders on eDiary to record the number of fecal incontinence episodes over the past 24 hours.	12-week of Double-Blind Treatment Period
Occurrence of treatment-emergent clinically significant laboratory abnormalities.		Through study completion, up to 19 weeks.

Collaborators and Investigators

• Sponsor: CinPhloro Pharma, LLC

Study record dates

Study Major Dates

• Study Start (Actual): December 28, 2023
• Primary Completion (Actual): July 28, 2025
• Study Completion (Actual): July 28, 2025

Study Registration Dates

• First Submitted: November 9, 2023
• First Submitted That Met QC Criteria: November 22, 2023
• First Posted (Actual): December 1, 2023

Study Record Updates

• Last Update Posted (Estimated): December 15, 2025
• Last Update Submitted That Met QC Criteria: December 9, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: Irritable Bowel Syndrome; IBS; IBS-D; IBS with diarrhea; Abdominal pain with diarrhea; IBS with loose stool
• Additional Relevant MeSH Terms: Intestinal Diseases; Digestive System Diseases; Gastrointestinal Diseases; Colonic Diseases; Colonic Diseases, Functional; Irritable Bowel Syndrome
• Other Study ID Numbers: CIN-103-121

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.: No