Are you living with Irritable Bowel Syndrome with Predominant Diarrhea (IBS-D)?

If so, consider joining the enviva study, a clinical trial investigating a new potential treatment for people living with IBS-D.

See if You May Qualify!

Are you living with Irritable Bowel Syndrome with Predominant Diarrhea (IBS-D)?

If so, consider joining the enviva study, a clinical trial investigating a new potential treatment for people living with IBS-D.

See if You May Qualify!

What is the enviva study?

enviva is a Phase 2 clinical research study. The goal of enviva is to explore the effect of an investigational drug on the symptoms of irritable bowel syndrome with predominant diarrhea (IBS-D). Researchers are studying how the investigational drug may help ease unpleasant symptoms, such as abdominal pain, bloating, and altered stool consistency.

Who can join the enviva study?

Study participants may be able to join the study if they meet the following requirements:

18 years of age or older

Confirmed diagnosis of IBS-D

Have no expected changes to their lifestyle, exercise routine, and/or diet during study participation

Are willing to complete a daily diary of symptoms through a mobile app

Other study requirements will apply.

What will happen during the study?

Participation in the enviva study lasts about lasts about 19 weeks. Study participants can expect the following:

Review & Sign the Informed Consent Form
The Informed Consent Form (ICF) contains information about the study including its goals, duration, benefits, risks, tests and procedures.
Screening Period
(Up to 3 Weeks)
Complete assessments to determine if you meet the requirements to participate in the study. Use of anti-diarrheal medication is allowed.
Baseline Period
(2 Weeks)
Receive instructions for completing the daily eDiary to record your symptoms of abdominal pain and bloating, as well as your stool consistency, frequency, and urgency.

Stop use of any anti-diarrheal medications, including medication used during the Screening Period.
Dosing Period
(12 Weeks)
Take your assigned dose by mouth twice daily, continue to complete the daily eDiary, and visit the study clinic 5 times for study assessments.

Use of anti-diarrheal medications should be limited and discussed with the study doctor.
Follow-up Period
(Up to 2 Weeks)
Talk to a member of the study team after your final dose. This visit may happen over the phone or at the study clinic.

Participation in a clinical study is voluntary. You can ask any questions you have and may leave the study at any time, for any reason.

Interested in the enviva study?

Take the pre-screener to see if you may qualify!

Take the Pre-Screener

About the Investigational Drug

What is the investigational drug?

The investigational drug, CIN-103, is a new formulation of a gastrointestinal drug called phloroglucinol. Phloroglucinol is used outside of the United States to relieve painful spasms within the GI tract. The investigational drug is designed to work similarly to help relieve symptoms of pain, cramping, and diarrhea by treating the painful spasms that occur in the GI tract.

Will I receive the study drug?

Participants are randomly assigned to a dose that may include either the investigational drug, a matching placebo, or a combination of the two.

What is an “investigational drug?”

Investigational means the study medication is not approved by regulatory authorities like the US Food and Drug Administration (FDA), and it can only be used in clinical research studies like enviva.

About Irritable Bowel Syndrome with Predominant Diarrhea (IBS-D)

What is IBS-D?

Irritable Bowel Syndrome is a collection of symptoms that appear together without the presence of damage or disease to the digestive tract. Individuals with IBS experience abdominal pain and changes to their bowel movements that include diarrhea, constipation, or both.

It is estimated that about 12% of the US population suffers from IBS. Factors that increase the likelihood of developing IBS include a family history of IBS, a history of stressful life events, and severe infection of the digestive tract.

The subtype of IBS known as Irritable Bowel Syndrome with Persistent Diarrhea (IBS-D) is defined by abnormal bowel movement where more than a quarter of stools are loose and watery.

Current therapy options include prescription medications, stress management, and dietary supplements. Enviva is researching an investigational drug that works differently than currently approved medications and has potential to help relieve unpleasant symptoms.

Where can I learn more?


National Institute of Diabetes and Digestive and Kidney Diseases. (2017). Definition & Facts for Irritable Bowel Syndrome. U.S. Department of Health and Human Services, National Institutes of Health. Retrieved November 10, 2023, from Definition & Facts for Irritable Bowel Syndrome - NIDDK (

Overview of Clinical Trials

Here are some common questions and answers about study participation.

If you have additional questions about participating in a clinical research study, contact a study clinic near you.

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