Amgen's venture arm has chipped in to a $30 million B round for Fremont, CA-based Ardelyx. The biotech plans to use a good deal of the cash to complete a Phase II study of a lead drug for constipation-predominant irritable bowel syndrome. NEA, CMEA and "certain individual investors" also joined in the venture funding.

Ardelyx has high hopes that its lead program--RDX5791, an NHE3 sodium transport inhibitor--can go on to become a first-in-class IBS treatment. Researchers said that in Phase I the drug triggered a "loosening of the stools and decreased time-to-first-stool similar to that seen in healthy adults with other approved IBS-C and constipation drugs." The current study is slated to wrap in early 2012.

"This Phase II trial data evaluating RDX5791 in patients with constipation-predominant irritable bowel syndrome are strategically important to Ardelyx because they will be our first efficacy results in a disease with significant un-met needs and an important demonstration of our unique approach to drug development," added Mike Raab, Chairman and CEO of Ardelyx. "Given the significant opportunities in our pipeline, our next priority is to establish partnerships in the US and abroad to advance our programs."

Founded four years ago, Ardelyx focuses much of its work on minimally-absorbed molecules designed to target the GI system, muffling any side effects. The biotech has raised $56 million.