Ardelyx Inc. sold the Canadian rights to its medicine tenapanor to Knight Therapeutics Inc.

The medicine has been evaluated in a late-stage trial to treat irritable bowel syndrome with constipation and is being studied in a second phase 3 study for hyperphosphatemia, which causes an abnormally elevated level of phosphate in the blood.

Fremont, Calif.-based Ardelyx will receive C$25 million for the rights. The amount includes an undisclosed up-front payment from Montreal-based Knight Therapeutics.

In December 2017, Ardelyx sold the rights to develop and commercialize the drug in China to Shanghai Fosun Pharmaceutical (Group) Co. Ltd. for an up-front payment of $12 million.