A Trial for New Treatment of Adult Participants With Irritable Bowel Syndrome

Inclusion Criteria

• Written consent on an Institutional Review Board (IRB)/ Independent Ethics Committee (IEC) approved informed consent form before any study specific evaluation
• Males and Females between 18 and 70 years of age
• Body Mass Index (BMI): 18-39 kg/m^2
• Having IBS-C or IBS-D as defined by Rome IV* including Subtype Classification as defined in Table 2
• Recurrent abdominal pain on average, at least 1 day/week in the last 3 months associated with two or more of the following criteria:
• Related to defecation
• Associated with a change in frequency of stool
• Associated with a change in form (appearance) of stool
• Have a moderate or severe IBS symptom severity score (> 175) as defined by IBS-SSS

Table 2:

IBS -C Abdominal Pain Intensity: weekly average of worst daily (in past 24 hours) abdominal pain score of > 3.0 on a 0 to 10-point scale And Stool Frequency: more than 25% of bowel movements with a consistency of Type 1 or Type 2 Bristol stool chart and less than 25% of bowel movements with Bristol stool form Type 6 or Type 7. Participants must have fewer than 3 complete spontaneous bowel movements (CSBMs) within a one week period (7 days)

IBS-D Abdominal Pain Intensity: weekly average of worst daily (in past 24 hours) abdominal pain score of > 3.0 on a 0 to 10-point scale And Stool Consistency: more than 25% of bowel movements with a consistency of Type 6 or Type 7 Bristol stool chart and less than 25% of bowel movements with Bristol stool form Type 1 or Type 2.Participants must have at least one Type 6 or Type 7 bowel movements on at least four days within a one week period (7 days).

Exclusion Criteria

• Males or females 70 years of age
• Have a IBS symptom severity score 39 kg/m^2
• Have a significant acute or chronic coexisting illness (cardiovascular, gastrointestinal, endocrine, immunological, metabolic or any condition which contraindicates, in the investigators' judgment, entry to the study)
• Confirmed clinical diagnosis of bile acid malabsorption and / or on medication for bile acid malabsorption
• Individuals who, in the opinion of the investigator, are poor attendees or unlikely for any reason to be able to comply with the study requirements
• Participant is currently enrolled in or has not yet completed at least 30 days since ending other investigational device or drug study(s), or participant is receiving other investigational agent(s)
• Have a malignant disease or any concomitant end-stage organ disease.
• Females who are pregnant or breast feeding
• Refusal to use acceptable methods of birth control (true abstinence, sterilisation, birth control pills, injections or contraceptive implants) for fertile participants (females) while on treatment and following completion of 2 menstrual cycles/ months after the last dose of study treatment. For Males, a barrier method of birth control from randomisation until the Follow-Up visit
• Use of antibiotics within 1 month of screening
• Use of systemic steroids within the last month
• Change in dose or introduction of an antipsychotic within the last month
• Have suffered from a major psychiatric disorder
• Clinically diagnosed Lactose intolerance
• Clinically diagnosed Coeliac disease
• Change of diet e.g. FODMAP, gluten-free within last 3 months
• Those > 50 will be excluded if their diagnosis of IBS is recent (<12 months) and if they have not had a sigmoidoscopy or colonoscopy within previous 5 years.
• Any gastrointestinal-related abdominal surgery other than hernia repair or appendectomy
• Participants taking prucalopride
• Other investigational procedures while participating in this study are excluded
• Known HIV infection, or hepatitis A, B, or C active infection
• Participants with abnormal laboratory values at screening deemed by the investigator to be clinically significant
• Participants who have taken commercially available probiotics within the last month (30 days prior to randomization)
• Pa