CAMBRIDGE, Mass. & PHILADELPHIA--(BUSINESS WIRE)--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).