BioWorld Today Contributing Writer

Ardelyx Inc. closed a $30 million Series B preferred stock financing that the company said will help fund completion by early 2012 of an ongoing 180-patient Phase II trial of lead candidate RDX5791 in patients with constipation-predominant irritable bowel syndrome (IBS-C) and a dose-ranging/regimen study of RDX5791 for prevention of excess dietary sodium absorption to control hypertension.

The Fremont, Calif.-based firm said new investor, Amgen Ventures LLC joined previous investors New Enterprise Associates Inc., CMEA Capital and unnamed individual investors in the round. It brings total funding for Ardelyx to $56 million since the company was formed in October 2007 with $1 million in seed money. A $25 million Series A followed in June 2008.

In addition to RDX5791, the company's pipeline includes preclinical candidates RDX002 in chronic kidney disease and RDX009 in Type II diabetes. But advancing RDX5791 through trials and finding partners will be the main focus for the next few months.

Ardelyx Chairman and CEO Mike Raab told BioWorld Today that the company will be meeting with potential partners in the U.S., Europe and Japan through September and October. He expects the Series B funds to see the company through mid-2012, and anticipates announcing partnerships in advance of or concurrent with the next round of financing, probably next year.

The company, which has a staff of 28, has intentionally done its early work quietly, Raab said. "Clinical data drive the day," he said, citing the 180-patient Phase II study as an example. "We believe a large trial is what partners would do if they were doing it themselves, that there's a need to run clinical studies that would have been run by prospective partners. We've built value with our clinical work and now we're looking for partners."

Depending on the results of current studies, he projects the start of a IBS-C Phase IIb or Phase III trial, and a Phase II hypertension study in spring 2012.

Ardelyx was founded in 2007 by Dominique Charmot, Peter Schultz and Jean Frechet to develop new non-absorbed and minimally absorbed small-molecule drugs.

Charmot, a polymer chemist who is Ardelyx's chief scientific officer, previously co-founded Ilypsa Inc., of Santa Clara, Calif., in 2003 – a company that ultimately was acquired by Amgen Inc. in June 2007 for $420 million – and developed polymeric drugs designed to selectively bind phosphate or potassium in the human gastrointestinal tract.

Schultz previously had founded and was the director of the Genomics Institute of the Novartis Research Foundation, in San Diego, as well as founding the Affymax Research Institute and several biotechs.

Polymer chemist Frechet, who currently is vice president for research at King Abdullah University of Science and Technology, in Saudi Arabia, previously had been on the faculty at the University of California Berkeley and holds more than 70 U.S. patents.

Ardelyx said that RDX5791, a minimally absorbed, orally administered NHE3 sodium transport inhibitor, is designed to prevent the absorption of sodium in the gastrointestinal tract, normalize the fluid balance and treat constipation and IBS-C.

The company said the Phase I trial of RDX5791 showed that, in a dose-dependent manner, it can cause a loosening of stools and decreased time-to-first stool similar to that seen in healthy adults with other approved IBS-C and constipation drugs. If successful, RDX5791 will be a first-in-class product in the category of intestinal sodium blockade, according to Ardelyx.

RDX5791 also is being studied at a different dosing level or regimen in a dose-ranging/regimen trial to evaluate whether it can help prevent absorption of excess dietary sodium and effectively emulate a low-sodium diet – potentially a new treatment for high blood pressure that may work with other hypertension drugs, the company said.

Also in the Ardelyx pipeline is RDX002, a preclinical candidate, which the company said is a minimally absorbed, orally administered NaP2b phosphate transport inhibitor for patients with chronic kidney disease.

The company said that, in animal models, RDX002 worked with phosphate binders to lower phosphate absorption, which may delay or prevent the progression of chronic kidney disease.

Also in preclinical development is RDX009, a non-absorbed agonist of TGR5, which is recognized as an important and valuable target for the treatment of Type II diabetes through direct induction of intestinal incretins such as GLP-1 and PYY.

By stimulating TGR5 in the intestines, RDX009 may have efficacy advantages over other traditional orally administered agents for Type II diabetes and may be safer because it is not absorbed.