Cardiokine Inc. is getting $50 million up front in a potential $220 million deal with Biogen Idec Inc. covering the vasopressin receptor antagonist lixivaptan.

Cardiokine retained the U.S. co-promotion option it was seeking, while Biogen Idec got a late-stage compound for its emerging cardiovascular franchise. The oral agent is expected to enter Phase III trials later this year for treating hyponatremia in patients with congestive heart failure, as well as in patients with cirrhosis and syndrome of inappropriate antidiuretic hormone.

Hyponatremia is an electrolyte disorder characterized by an imbalance of sodium and water in the body. Cardiokine CEO David Brand said the condition affects 1 million-plus hospitalized patients in the U.S. and about 1.5 million people diagnosed on an outpatient basis.

Brand told BioWorld Today that Cardiokine had a number of partnering opportunities for the product, and chose Biogen Idec because of its commitment to and plans for the product, as well as for the financial aspects of the deal.

Cardiokine is entitled to up to $170 million in milestone payments in the partnership, along with undisclosed development support, Brand said. Biogen will be responsible for worldwide commercialization, and would pay royalties on resulting sales to Cardiokine, which retained an option to limited co-promotion rights in the U.S.

Cardiokine was formed in March 2004 around a licensing deal with Wyeth covering lixivaptan, a selective V2 vasopressin receptor antagonist. It has raised $87 million in two financings rounds, and has completed Phase II trials of the drug. Brand said the Phase II program encompassing more than 300 patients at trial sites in Europe, Canada and the U.S. - and the three diseases - demonstrated effectiveness in correcting hyponatremia.

Details on the upcoming Phase III program were not disclosed, except that Brand said it also would include sites in Canada and Europe. The trials, he said, would be expected to take two years to complete, putting a potential new drug application filing around mid-2010 if all went according to plan.

In May 2006, when Cardiokine raised $50 million in a Series B financing, Brand had projected the trials would start later that year. But instead, the company conducted further characterization studies, a move that resulted in a better candidate, he said.

Cardiokine said lixivaptan antagonizes the action of vasopressin (also known as antidiuretic hormone) on the V2 receptors in the kidney-collecting duct, causing water to be excreted from the kidney, without affecting sodium or other electrolytes. Based on that mechanism of action, lixivaptan could be used in treating disease states associated with water retention and electrolyte imbalance.

Hyponatremia, the company said, is the most common electrolyte disorder in clinical practice and is recognized as an independent contributor to negative patient outcomes in many chronic diseases, most notably congestive heart failure.

Cardiokine has maintained a low profile since its founding, disclosing news only on its $37 million Series A financing, the hiring of Brand, the Series B round and now the Biogen Idec deal. Terms of the exclusive licensing deal with Wyeth on lixivaptan were not disclosed.

Cardiokine has expressed interest in adding a product to its pipeline to supplement lixivaptan, its sole drug candidate. Those talks now are expected to pick up steam.

"We've been very active in looking at a number of compounds," Brand said. "The completion of this partnership gives us a great deal of impetus for talking to a number of people we have spoken with in the past. Our goal is to look at compounds in cardiovascular/metabolic areas that fit into this franchise area. There are a number of them out there."

Biogen Idec, which has focused mostly in the areas of oncology, neurology and immunology, has talked about its interest in branching into specialty markets with unmet needs that are served by a concentrated number of physicians. Its interest in the cardiovascular area was shown by a licensing deal in September that gave it rights to the Phase II product Aviptadil, a pulmonary arterial hypertension candidate from mondoBiotech AG, of Basel, Switzerland. Biogen Idec also has a license to Adentri, an A1-adenosine receptor antagonist for treatment of heart failure, from CV Therapeutics Inc., of Palo Alto, Calif.

Among Cambridge, Mass.-based Biogen Idec's marketed products are treatments for multiple sclerosis, rheumatoid arthritis and lymphoma. Early this year, Biogen Idec acquired Syntonix Pharmaceuticals Inc. in exchange for $40 million at closing and up to $80 million in development milestones. Among the products acquired were two preclinical programs in hemophilia. (See BioWorld Today, Sept. 15, 2006, and Jan. 5, 2007.)

Brand said Cardiokine was looking for a partner with capabilities in both the commercial side of the business and in the development of specialty products. At the same time, Cardiokine was looking for an opportunity to establish its own cardiovascular franchise on which to build future development.

"It was an excellent foundation to form a partnership on," Brand said.

Biogen officials could not be reached for comment.