Efficacy and Safety, Tolerability of GA-AT0119 in IBS-C

Each subject will be asked to sign the Informed Consent Form (ICF). The patients diagnosed with IBS-C will be randomized in 1:1 ratio. The treatment will be administrated according to the approved leaflet and study procedures. Eligible patients will be randomized to receive either GA-AT0119 or Placebo. Patients will be treated according to the approved leaflet. The study subjects will return at day 7, 15 and day 28 for evaluation. Each subject will undergo a washout period of 28 days. At Day 56 each subject will be evaluated and will receive the crossover therapy line and start administration. Subject will be evaluated at Day 84 at the end of the crossover period. Patients will be evaluated for constipation symptoms, global assessment for tolerability, safety. Each subject will receive a diary where bowel frequency, type and transit time will be completed during product administration. From visit 2 to visit 6, patients will be evaluated for treatment adherence and clinical symptoms recurrences. Each subject will complete 2 additional phone follow-ups Visit for safety reporting and clinical symptoms recurrences according to protocol. During the follow-up visits subject will be evaluated also by using Likert scale for Abdominal Pain and discomfort, Sickness Impact Profile score, IBS-VAS scale and IBS-QoL.