FDA publishes final IBS guidance

FDA issued final guidance on the design of clinical trials for diarrhea- or constipation-predominant irritable bowel syndrome (IBS-D or IBS-C). The guidance is in line with a draft released in March 2010. The agency said the ideal primary endpoint for IBS trials is a patient-reported outcome (PRO) instrument that measures the clinically important signs and symptoms associated with each IBS subtype. However, since a validated instrument is not yet available, the guidance recommends a co-primary endpoint consisting of pain intensity and either stool frequency for IBS-C trials or stool consistency for IBS-D trials. FDA said a single endpoint could support approval of a drug that has a mechanism of action targeting only one sign or symptom, as long as the other symptoms or signs are not worsened by treatment. ...