The Current Landscape of IBS Clinical Trials in 2023

Irritable bowel syndrome (IBS) is a highly prevalent, functional gastrointestinal condition that is both costly and debilitating. Between 9% and 23% of the general population suffers from IBS, with 80% of patients identifying as women. It is also linked to psychological conditions such as depression and anxiety, which is why IBS clinical trials are important. [1]

Symptoms of IBS include frequently recurring abdominal pain (at least one day per week for three months) and changes in bowel habits (defecation, change in stool frequency, and change in stool appearance). Additionally, IBS may present with flatulence, the feeling of incomplete defecation, and/or abdominal pain. As a result, IBS patients experience a severe impact on their productivity and ability to function day-to-day.

There are three forms of IBS in gastroenterology:

  • Constipation-predominant (IBS-C)
  • Diarrhea-predominant (IBS-D)
  • Mixed (IBS-M)

The underlying pathophysiology of IBS remains unknown. Modern research suggests it is a disorder of disrupted gut-brain interactions, with anomalies such as increased intestinal permeability or altered gut flora, occurring along the gut-brain axis. [2]

Current Avenues for Treatment of IBS

Modern medicine treats IBS with several approaches. The goal of any IBS treatment is to provide relief for symptoms – there is no existing cure. These treatments depend on the type and severity of symptoms and are typically customized for each patient. [3]

Dietary and lifestyle changes

Symptoms of IBS include bloating, abdominal pain, and diarrhea, all of which may respond to changes in a person’s diet. Dietary changes involve reducing symptom-causing foods and increasing the consumption of more nutritional foods. Gastroenterologists may work in tandem with a dietitian to formulate a program or refer you to one.

Some dietary recommendations that a gastroenterologist may make include:

  • Eating more fiber-rich foods
  • Avoiding gluten and dairy products
  • Decreasing carbohydrate intake
  • Implementing a low FODMAPS diet

Additionally, your gastroenterologist may recommend that you increase your physical activity and ensure you get adequate sleep. Minimizing or mitigating stress may also help.


Doctors may prescribe medication to treat IBS, depending on how your symptoms present. If this is the case, it is important to communicate any medicines you currently take to ensure there are no contraindications.

For diarrhea, your doctor may prescribe antidiarrheal medications that will slow intestinal transit and reduce the frequency of bowel movements, while improving stool consistency. These medications include loperamide, eluxadoline, and rifaximin.

For constipation, doctors may recommend laxatives and fiber supplements. These may come with a prescription for smooth muscle relaxants to reduce or prevent intestinal cramping. Other medications that treat abdominal pain include antispasmodics and low-dose antidepressants.


Many body systems and functions are interconnected, and there is a strong link between the nervous system and the functions of your digestive system. Stress, anxiety, and depression are significant factors in the frequency and severity of IBS symptoms, and can often precede an IBS diagnosis.

Cognitive behavioral therapy (CBT) has been shown to improve IBS symptoms by helping patients transform their thought and behavior patterns. Doctors may also consider gut-directed hypnotherapy to manage symptoms. [4]

Alternative treatments

A doctor may recommend probiotics to balance the gut microbiome. Introducing live microorganisms, such as good bacteria found in your digestive tract, can reprogram the flora in your gut and reduce IBS symptoms. Research is still ongoing regarding the use of probiotics to treat IBS, but results so far have been promising in symptom management.

Acupuncture and therapeutic massages may help reduce anxiety, stress, and insomnia associated with IBS. Acupuncture can also affect gastrointestinal motility and pain perception.

IBS Clinical Trials

The prevalence of IBS, alongside the lack of insight into the underlying pathophysiology, has led to a host of clinical trials that target the development of IBS treatments or study the efficacy of existing therapies on IBS symptoms.

Ibodutant treatment for IBS-D

The Menarini Group ran an IBS clinical trial evaluating the efficacy and safety of neurokinin type-2 receptor antagonist, ibodutant, for IBS-D symptoms. The trial tested three different doses of ibodutant alongside a placebo, given once daily for 8 weeks in a double-blind phase II trial.

Patients were given a placebo or low dose, intermediate dose, or high dose of ibodutant, all taken in fasting conditions. The primary outcome measured was the response to the relief of overall IBS-D symptoms and abdominal pain or discomfort – with “response” defined as satisfactory for at least 6 out of 8 weeks (75% rule).

Other outcomes measured were quality of life changes and relief according to the 75% rule in both male and female patient demographics. [5]

Eluxadoline for Bile Acid Malabsorption (BAM)

An IBS clinical trial conducted by Allergan evaluated the possibility of differential effects of eluxadoline on altered bowel function in IBS-D participants, with and without evidence of BAM. Eluxadoline is a Schedule IV controlled substance and is a mixed mu-opioid receptor agonist. This drug has been approved to treat IBS-D symptoms.

Eluxadoline is typically prescribed in 100mg oral tablets to IBS-D patients with and without evidence of BAM, with all patients taking the drug alongside food. The registrational clinical trial’s primary and safety outcomes included:

  • Changes in stool consistency
  • Treatment-emergent adverse events
  • Clinically significant changes in laboratory tests
  • Clinically significant changes in vital signs
  • Clinically significant changes in general physical condition [6]

Gastrointestinal Reprogramming Product (GaRP)

Anatara Lifesciences is currently developing a GaRP – a regenerative, multi-component complementary medication designed to address underlying factors associated with chronic gastrointestinal conditions such as IBS.

The GaRP product has undergone in vitro and in vivo preclinical trials that support its effectiveness in removing pro-inflammatory bacteria, reducing inflammation, regenerating gastrointestinal tract integrity, and stimulating mucosal healing.

GaRP features a triple-targeted therapeutic approach (anti-adhesion, anti-inflammatory, and mucosal regeneration) and dual-targeted formulation. [7]

Blautix for treating IBS

Blautix is a treatment developed by 4D Pharma. In its Phase II double-blind trial, the company evaluated the effectiveness of oral doses in adults with IBS. Participants with either IBS-C or IBS-D received either Blautix (2 capsules taken orally, twice daily) or a placebo.

Blautix is a live biotherapeutic product containing a lyophilised formulation of bacterium.

Over the course of 8 weeks, participants answered QoL questionnaires regarding abdominal pain intensity, IBS symptom severity, quality of life, anxiety and depression, stool frequency and consistency, and food frequency. [8] 4D Pharma is currently working towards initiating a Phase III trial investigating Blautix’s safety and efficacy.

Efficacy of psycho-therapy for functional bowel disorders

Instead of medication, this clinical trial intends to study the links between bowel symptoms, quality of life, and personal factors that affect health. The study looks at the effectiveness of psychological therapies such as CBT on patients suffering from functional bowel disorders such as IBS, who also have a history of adverse life events or post-traumatic stress disorder (PTSD).

To begin, researchers will conduct a cross-sectional survey examining the prevalence of early adverse life events (EALS) and PTSD among patients with either IBS-C or chronic constipation. Following that, the study will recruit patients with PTSD or EALS for outpatient CBT.

The study will measure changes in completed spontaneous bowel movements and abdominal pain. [9]

IBS Clinical Trials “Pipeline” Boom in 2023

DelveInsight posted a report in 2023 that gave a comprehensive overview of available, marketed, and pipeline IBS therapies in various phases of clinical development. The report featured over 24 companies and over 24 pipeline drugs for the treatment of IBS.

Promising pipeline therapies include Olorinab, Blautix, ORP-101, Rifamycin controlled-release, and several other treatments. IBS-specialized companies leading the way included Arena Pharmaceuticals, 4D Pharma, Boston Pharmaceuticals, and others. These companies are presently evaluating novel IBS medications that may improve treatment and symptom management.

For example, Pfizer is currently developing Olorinab, a cannabinoid receptor CB2 agonist in Phase II of clinical trials. 4D Pharma is working on Blautix, a gastrointestinal microbiome modulator. Boston Pharmaceuticals has BOS-589, a protein tyrosine kinase inhibitor in Phase II as well. [10]

CROs and Clinical Trials

Pharmaceutical and biotech companies often struggle to develop these drugs and treatments in isolation. Sponsors partner with contract research organizations (CROs) to execute IBS clinical trials that test the efficacy and safety of their treatments on human subjects. Evrima, for example, is conducting a clinical trial on Anatara’s GaRP treatment across Australia.

Other CROs that have valuable expertise and experience in gastroenterology clinical trials include Altasciences, Caidya, Criterium, Duke Clinical Research Institute, and Vial. These organizations offer comprehensive clinical trial services for gastrointestinal conditions – including IBS.

Vial is an industry-leading CRO powered by next-generation technologies, with the vision to reimagine clinical trials. Backed by an accomplished ClinOps team, technology leaders, and scientific advisors, Vial delivers faster, better, and cheaper gastroenterology clinical trials for sponsors. If you’re interested in a proposal, contact us today!

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