Astellas Pharma Inc. today announced that it has received a Japanese marketing approval for Irribow(R) Tablets 2.5g, 5g for the diarrhea-predominant irritable bowel syndrome in male.

Japan | July 17, 2008 | Astellas Pharma Inc. (headquarters: Tokyo, president and CEO: Masafumi Nogimori, “Astellas”) today announced that it has received a Japanese marketing approval for Irribow® Tablets 2.5g, 5g (generic name: ramosetron hydrochloride) for the diarrhea-predominant irritable bowel syndrome in male. A New Drug Application had been submitted in January 2006.

Irritable bowel syndrome (IBS) is a functional but not organic disorder which causes abdominal pain and/or discomfort with abnormal defecation including diarrhea and constipation. These gastrointestinal symptoms persist for a long period with frequent remissions and exacerbations. Abdominal pain/discomfort and abnormal defecation are often associated with many factors such as stress, which is considered to cause the acceleration of intestinal transit resulted from the over-activation of enteric nervous system.

Irribow is a serotonin 5-HT3 receptor antagonist discovered by Astellas. Serotonin is a member of neurotransmitter which is greatly related to gastrointestinal motility, secretion and sensation. Stress may stimulate the serotonin release and activate the 5-HT3 receptors on enteric nerve, which induces the acceleration of intestinal transit resulting in diarrhea. In addition, the increase in intracolonic pressure also induces serotonin release, and it will bind to 5-HT3 receptor at the terminal of afferent neuron, causing intestinal nociceptive transmission to central nervous system.

Irribow improves abnormal defecation associated with the acceleration of intestinal transit by inhibiting 5-HT3 receptor selectively. It also improves visceral hypersensitivity by suppressing the transmission of intestinal nociception.

Astellas expects Irribow to provide a new option for IBS medication. The launch timing will be announced after it appears in the NHI Drug Price List

SOURCE: Astellas Pharma Inc.

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