FDA publishes IBS draft guidance

FDA issued draft guidance on the design of clinical trials for diarrhea- or constipation-predominant irritable bowel syndrome (IBS-D or IBS-C). 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 single-item patient-reported ratings of overall change in IBS symptoms should no longer be used as primary endpoints. The PRO Consortium, established in 2008 under FDA's Critical Path Initiative, is developing subtype-specific IBS PRO instruments. ...