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

A study to evaluate the effectiveness of oral doses of Blautix in adult participants with irritable bowel syndrome (IBS).

Participants with a diagnosis of IBS will be enrolled as defined by Rome IV criteria and will be classified into cohorts according to the Rome IV classification of IBS subtypes.

Each cohort (Cohort C and Cohort D) will recruit participants who will randomly receive either Blautix or matching placebo in a 1:1 ratio overall of treated to control participants.

Participants will undergo five visits in total across approximately 13 weeks. During the study treatment phase, participants will be asked to complete a variety of Quality of Life questionnaires at certain time points. These will consist of abdominal pain intensity score, IBS symptom severity (IBS-SSS), IBS quality of life (IBS-QoL), hospital anxiety and depression score (HADS), stool frequency, stool consistency \& food frequency questionnaire.

Participants will be required to produce relevant blood, urine and faecal samples at pre-determined timepoints from screening through to End of Treatment and follow up visits.

Eligibility Criteria:
Inclusion Criteria:

1. Written consent on an Institutional Review Board (IRB)/ Independent Ethics Committee (IEC) approved informed consent form before any study specific evaluation
2. Males and Females between 18 and 70 years of age
3. Body Mass Index (BMI): 18-39 kg/m\^2
4. 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
5. 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:

1. Males or females \<18 and \>70 years of age
2. Have a IBS symptom severity score \< 175 as defined by IBS-SSS
3. BMI: \<18 or \>39 kg/m\^2
4. 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)
5. Confirmed clinical diagnosis of bile acid malabsorption and / or on medication for bile acid malabsorption
6. 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
7. 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)
8. Have a malignant disease or any concomitant end-stage organ disease.
9. Females who are pregnant or breast feeding
10. 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
11. Use of antibiotics within 1 month of screening
12. Use of systemic steroids within the last month
13. Change in dose or introduction of an antipsychotic within the last month
14. Have suffered from a major psychiatric disorder
15. Clinically diagnosed Lactose intolerance
16. Clinically diagnosed Coeliac disease
17. Change of diet e.g. FODMAP, gluten-free within last 3 months
18. 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.
19. Any gastrointestinal-related abdominal surgery other than hernia repair or appendectomy
20. Participants taking prucalopride
21. Other investigational procedures while participating in this study are excluded
22. Known HIV infection, or hepatitis A, B, or C active infection
23. Participants with abnormal laboratory values at screening deemed by the investigator to be clinically significant
24. Participants who have taken commercially available probiotics within the last month (30 days prior to randomization)
25. Participants with known or suspected hereditary fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltose insufficiency
26. Participants taking guanylate cyclase agonists, such as linaclotide and lubiprostone