Ibodutant was a candidate drug for irritable bowel syndrome diarrhea, developed by The Menarini Group. As of March 2015^[update], it underwent a multicentre double blind efficacy clinical study. Ibodutant selectively blocks the tachykinin receptor NK₂, with blockade practically complete in nanomolar concentrations. A phase 2 trial in Europe (the IRIS-2 trial) completed in May 2012 with positive results. A 52-week phase 3 study was terminated as of 2015 because of low response and negative results of study NAK-06.