CAMBRIDGE, Mass.--(BUSINESS WIRE)--Biogen Idec (NASDAQ: BIIB) has announced that positive results of a Phase II study of oral ADENTRI®, an A1 adenosine receptor antagonist, in stable heart failure patients have been published in today’s issue of the Journal of the American College of Cardiology. Results showed that administration of oral ADENTRI for 10 days, in addition to standard heart failure therapy, was well tolerated and resulted in clinically significant increases in sodium excretion while preserving renal function.