The company said the drug, Rifamycin, met the primary endpoint of reducing the time to last unformed stool in patients with travelers' diarrhea — a common intestinal infection.

Rifamycin's U.S. development and marketing rights were acquired by Santarus from Cosmo Technologies Limited in 2008.

Santarus said the drug, covered by two U.S. patents that expire in 2020 and 2025, was generally well tolerated in the study.

About 10 million people develop diarrhea primarily caused by bacteria every year, the company said citing the U.S. Centers for Disease Control and Prevention.

Shares of San Diego, California-based Santarus were up at $8.14 in extended trading. They closed at $7.80 on the Nasdaq on Tuesday.

(Reporting By Pallavi Ail in Bangalore; Editing by Joyjeet Das)

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