Biogen Idec and CardioKine partner to develop Lixivaptan, a novel Vasopressin Antagonist

Lixivaptan to enter Phase III clinical trial in 2007 in heart failure patients.

Cambridge, MA and Philadelphia, PA (July 2, 2007) – Biogen Idec (NASDAQ: BIIB) and Cardiokine, Inc., a privately-held specialty pharmaceutical company focused on the development of drugs for the treatment of heart failure and related indications, today announced the signing of an agreement to jointly develop lixivaptan, an oral compound expected to enter a Phase III clinical trial this year for the potential treatment of hyponatremia in patients with congestive heart failure (CHF).

Lixivaptan is a selective V2 vasopressin receptor antagonist that, in clinical trials, has demonstrated promising activity in treating hyponatremia, an imbalance of sodium and water in the body. Lixivaptan works by causing water to be excreted from the kidney, without affecting sodium or other electrolytes. Particularly in heart failure patients, hyponatremia is associated with volume overload, a key symptom leading to hospitalization of these patients. In addition, hyponatremia is an important feature of other disorders including liver cirrhosis and syndrome of inappropriate antidiuretic hormone (SIADH), and can contribute to morbidity and negative outcomes.

“With this late-stage oral compound, we continue to leverage our global development and specialty market expertise to grow our business and broaden our therapeutic focus. An effective treatment for hyponatremia could be beneficial to patients with a variety of diseases, including heart failure,” said James C. Mullen, Biogen Idec’s President and Chief Executive Officer (CEO). “This program will expand our efforts in cardiovascular care and we look forward to working with Cardiokine to deliver this promising new product for patients.”

“We are extremely pleased to be partnering lixivaptan with Biogen Idec. We share an appreciation of the adverse health consequences associated with hyponatremia and have a common vision for lixivaptan. Biogen Idec’s proven development and commercialization capabilities in concert with Cardiokine’s development team will make this vision a reality,” said David Brand, President and CEO of Cardiokine.

Under terms of the agreement, Cardiokine will receive a $50 million upfront payment and up to $170 million in additional milestone payments for successful development and global commercialization of lixivaptan, as well as royalties on commercial sales. Biogen Idec will be responsible for the global commercialization of lixivaptan and Cardiokine will have an option for limited co-promotion in the United States (U.S.). The agreement is expected to become effective in the third quarter of 2007, and is subject to the satisfaction of certain closing conditions and customary approvals.

***

About lixivaptan:
Lixivaptan is a highly potent, non-peptide, selective V2 vasopressin receptor antagonist. It antagonizes the action of vasopressin (also known as antidiuretic hormone, ADH) 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 this mechanism of action, lixivaptan shows promise in the treatment of disease states associated with water retention and electrolyte imbalance.

About hyponatremia:
Hyponatremia is the most common electrolyte disorder in clinical practice. It is estimated that the incidence of hyponatremia in hospitalized patients in the U.S. is greater than one million. Hyponatremia is recognized as an independent contributor to negative patient outcomes in many chronic diseases, most notably CHF, as well as cirrhosis and SIADH.

About Cardiokine:
Cardiokine, headquartered in Philadelphia, is a privately held specialty pharmaceutical company focused on the development of pharmaceuticals for the treatment and prevention of heart failure and related cardiovascular and metabolic indications. Additional information about Cardiokine is available at www.cardiokine.com.

About Biogen Idec:
Biogen Idec creates new standards of care in therapeutic areas with high unmet medical needs. Founded in 1978, Biogen Idec is a global leader in the discovery, development, manufacturing, and commercialization of innovative therapies. Patients in more than 90 countries benefit from Biogen Idec's significant products that address diseases such as lymphoma, multiple sclerosis, and rheumatoid arthritis. For press releases and additional information about the company, please visit, www.biogenidec.com.

Biogen Idec Safe Harbor:
This press release contains forward-looking statements regarding the agreement with Cardiokine and the development of lixivaptan. These statements are based on the companies' current beliefs and expectations. Drug development involves a high degree of risk. Only a small number of research and development programs result in commercialization of a product. Factors which could cause actual results to differ materially from Biogen Idec’s current expectations include the risk that the company may not be able to demonstrate the safety and efficacy of lixivaptan at each stage of the clinical trial process; technical hurdles relating to the manufacture of lixivaptan may be encountered; the company may not be able to meet applicable regulatory standards or regulatory authorities may fail to approve lixivaptan; and the company may encounter other unexpected hurdles.

For more detailed information on the risks and uncertainties associated with Biogen Idec’s drug development activities, see the section entitled “Risk Factors” in Biogen Idec’s quarterly report on Form 10-Q for the fiscal quarter ended March 31, 2007 that was filed with the Securities and Exchange Commission, as well as other periodic and current reports of Biogen Idec filed with the Securities and Exchange Commission. Biogen Idec assumes no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.

Back