(Reuters) - Irish drugmaker Shire Plc (>> Shire PLC) said it would buy the rights to an experimental bowel drug from Pfizer Inc (>> Pfizer Inc.) to bolster its pipeline of gastrointestinal treatments.

The drug, PF-00547659, which is designed to treat moderate-to-severe inflammatory bowel disease, has successfully completed mid-stage studies, Shire said on Tuesday.

Inflammatory bowel disease is a condition that affects either part or all of the digestive tract and the cause of the disease is unknown.

Shire's portfolio of gastrointestinal drugs includes approved treatments such as Vynase for binge-eating disorder and Gattex for short bowel syndrome.

Howard Mayer, the company's head of clinical development, said the licensing deal fits with the company's focus of developing treatments for gastrointestinal conditions that affect a small group of patients.

Two of the company's experimental drugs, aimed at treating rare gastric diseases, were given breakthrough designation on Monday by the U.S. Food and Drug Administration.

Breakthrough therapy designation speeds up the development and review of medicines intended to treat serious or life-threatening diseases.

(Reporting by Vidya L Nathan in Bengaluru, Editing by Anil D'Silva)

Stocks treated in this article : Shire PLC, Pfizer Inc.