EFFECT OF NEUROKININ 2 RECEPTOR ANTAGONIST (SR48968C) ON RECTAL SENSATION

This is a single-center study that has been developed in collaboration with the PI. Patients with irritable bowel syndrome (IBS) associated with increased frequency of bowel movements or urgency have rectal hypersensitivity. In this phase IIA parallel-group study, 24 patients with diarrhea-predominant IBS will be evaluated over approximately one month. Neurokinins (e.g., substances P and K) are known to modulate colonic smooth muscle function by noncholinergic excitation and to mediate visceral sensation at periphreal and spinal cord levels. Our hypothesis is that SR48968C, a neurokinin-2 receptor antagonist, reduces rectal sensitivity in patients with diarrhea-predominant IBS. Recruitment to the study was very slow (3 patients in 6 months), and the company was notified of our concerns. The sponsor decided it was not worth pursuing this study, so it was closed. Since only three patients were studied, no meaningful data can be abstracted.