Two Gencaro™ Atrial Fibrillation Abstracts Accepted for Presentation at the American Heart Association Scientific Sessions 2011

ARCA biopharma, Inc., a biopharmaceutical company developing genetically-targeted therapies for atrial fibrillation and other cardiovascular diseases, announced that two Gencaro (bucindolol hydrochloride) abstracts have been selected for oral presentation at the American Heart Association's Scientific Sessions 2011, being held November 12-16, 2011 in Orlando, Florida. The abstracts present atrial fibrillation data from the pivotal Phase 3 BEST trial of Gencaro. Dr. Ryan Aleong, Assistant Professor of Medicine, Cardiology, Director of Implanted Cardiac Device Clinic, University of Colorado Hospital, and Interim Director of Arrhythmia Services at Denver Health Medical Center, is scheduled to present both abstracts: -- "Prevention of Atrial Fibrillation by Bucindolol is Completely Dependent on the Beta-1 389 Arg/Gly Adrenergic Receptor Polymorphism." (expanded panel discussion -- epd.400.03 -- atrial fibrillation:Novel Insights into Mechanisms)(expanded panel discussion -- epd.400.03 -- atrial fibrillation:Wednesday)(expanded panel discussion -- epd.400.03 -- atrial fibrillation:November 16)(expanded panel discussion -- epd.400.03 -- atrial fibrillation:2011)(from 9:00 a.m. to 11). -- "Is New Onset Atrial Fibrillation a Surrogate Marker for Heart Failure Progression?" (Abstract Oral Session -- AOS.516.01 -- Ventricular Function/Hemodynamics and Biomarkers; Wednesday, November 16, 2011, from 2:00 p.m. to 5:10 p.m. Eastern). Gencaro Phase 3 Atrial Fibrillation Clinical Trial The Company plans to conduct a Phase 3, multi-center, randomized, double-blind clinical trial of Gencaro in approximately 300-400 new onset atrial fibrillation patients with HFREF. The Company believes the planned study will provide important clinical data on the safety and efficacy of Gencaro in this patient population and additional information on the pharmacogenetic selectivity of Gencaro. The primary endpoint of the trial will be time to recurrent symptomatic atrial fibrillation after electrical cardioversion. The Company is planning for the atrial fibrillation trial to compare Gencaro to the beta-blocker metoprolol CR/XL in patients with the genotype (homozygous arginine position of the beta1389 adrenergic receptor) in which Gencaro appears to demonstrate therapeutic enhancement. Metroprolol CR/XL does not appear to have enhancement of efficacy in patients with this genotype. The Company believes the planned trial would take approximately two years from enrollment of the first patient to completion. Subject to obtaining additional financing, the Company anticipates initiating patient enrollment in the trial in the first half of 2012. About ARCA biopharma ARCA biopharma is dedicated to developing genetically-targeted therapies for cardiovascular diseases. The Company's lead product candidate, Gencaro(TM) (bucindolol hydrochloride), is an investigational, pharmacologically-unique beta-blocker and mild vasodilator being developed for the prevention of atrial fibrillation in patients with heart failure. ARCA has identified common genetic variations in the cardiovascular system that it believes interact with Gencaro's pharmacology and may predict individual patient response to Gencaro, giving it the potential to be the first genetically-targeted treatment for the prevention of atrial fibrillation. ARCA is collaborating with Laboratory Corporation of America to develop the companion genetic test for Gencaro.