CORRECTING AND REPLACING GencaroTM Cardiovascular Effect on Patients with Atrial Fibrillation Paper Published in European

  CORRECTING AND REPLACING GencaroTM Cardiovascular Effect on Patients with
  Atrial Fibrillation Paper Published in European Journal of Heart Failure

CORRECTION...by Business Wire

Business Wire

BROOMFIELD, Colo. -- December 12, 2012

First graph of release should read: ARCA biopharma, Inc. (Nasdaq: ABIO), a
biopharmaceutical company developing genetically-targeted therapies for atrial
fibrillation and other cardiovascular diseases, today announced that the paper
"Effect of Bucindolol (Gencaro) on Heart Failure Outcomes and Heart Rate
Response in Patients with Reduced Ejection Fraction Heart Failure and Atrial
Fibrillation” was published in the European Journal of Heart Failure
(www.escardio.org/journals/european-journal-heart-failure), a publication of
the Heart Failure Association of the European Society of Cardiology (sted ARCA
biopharma, Inc. (Nasdaq: ABIO) announces the paper "Effect of Bucindolol
(Gencaro) on Heart Failure Outcomes and Heart Rate Response in Patients with
Reduced Ejection Fraction Heart Failure and Atrial Fibrillation” was
published).

The corrected release reads:

 GENCARO^TM CARDIOVASCULAR EFFECT ON PATIENTS WITH ATRIAL FIBRILLATION PAPER
                PUBLISHED IN EUROPEAN JOURNAL OF HEART FAILURE

ARCA biopharma, Inc. (Nasdaq: ABIO), a biopharmaceutical company developing
genetically-targeted therapies for atrial fibrillation and other
cardiovascular diseases, today announced that the paper "Effect of Bucindolol
(Gencaro) on Heart Failure Outcomes and Heart Rate Response in Patients with
Reduced Ejection Fraction Heart Failure and Atrial Fibrillation” was published
in the European Journal of Heart Failure
(www.escardio.org/journals/european-journal-heart-failure), a publication of
the Heart Failure Association of the European Society of Cardiology.

The paper discusses post-hoc analyses of data from the Phase 3 clinical study
of Gencaro in heart failure, known as the Beta-Blocker Evaluation of Survival
Trial (BEST), which was sponsored by the National Heart, Lung and Blood
Institute of the National Institutes of Health, and the Cooperative Studies
Program of the Department of Veterans Affairs. These data demonstrate that
patients with established atrial fibrillation (AF) in BEST who received
Gencaro had improvements in heart failure clinical endpoints. Compared to
placebo, the effects of Gencaro on improving heart failure clinical endpoints
in the 303 patients in BEST with established AF were generally similar to the
effects of Gencaro on these endpoints in the 2,176 patients in BEST with
normal sinus rhythm.

The data also demonstrate that Gencaro made it more likely for patients with
established AF to achieve ventricular rate control, and that Gencaro improved
cardiovascular clinical endpoints for those AF patients who did achieve rate
control. 67% of AF patients who received Gencaro achieved ventricular response
rate control, defined as a resting heart rate of less than or equal to 80
beats per minute without symptomatic bradycardia (p < 0.005). In AF patients
who achieved ventricular response rate control, Gencaro produced a 39%
reduction (p = 0.025) in cardiovascular mortality/cardiovascular
hospitalizations. In addition, Gencaro also improved cardiovascular clinical
endpoints for those AF patients possessing the genotype which ARCA believes is
most favorable for Gencaro response. In a substudy of 1,040 patients in BEST
in which patient genotypes were analyzed, Gencaro was associated with a 72%
decrease (p = 0.039) in cardiovascular mortality/cardiovascular
hospitalizations in those 52 AF patients in the substudy with the beta-1 389
arginine homozygous genotype. ARCA believes that this genotype predicts a
favorable response to Gencaro, and is estimated to be present in about 50% of
the population in the U.S. These data are in contrast to the data reported for
studies of other beta-blockers, including carvedilol, in which AF patients
with the beta-1 389 arginine homozygous genotype who received those drugs
exhibited evidence of resistance to heart rate reduction.

Christopher O'Connor, MD, Professor of Medicine and Cardiologist, Duke
University Medical Center, and a co-author of the paper commented, "In placebo
controlled trials of patients with heart failure and reduced left ventricular
ejection fraction (HFREF) who also have permanent AF, currently approved beta
blockers have not shown benefit by improving clinical endpoints. In this
study, Gencaro ^ exhibited evidence of efficacy against clinical endpoints in
patients with HFREF and AF. In addition, this efficacy appears to be
pharmacogenetically enhanced in patients with the beta-1 389 arginine
homozygous genotype, and rate control was also effective in this genotype.
This evidence of rate control by Gencaro in this genotype is important because
it has been reported that other beta-blockers do not provide adequate rate
control in AF patients with this genotype."

Michael Bristow, MD, PhD, President and CEO of ARCA biopharma and Professor of
Medicine (Cardiology) at the University of Colorado Anschutz Medical Campus,
and a senior author of the paper added, "These data from the BEST study
suggest that Gencaro may be safe and effective in patients with permanent AF.
ARCA would be able to further test this hypothesis in its proposed trial of
Gencaro in AF prevention."

ARCA has been granted patents in the U.S., Europe, and other jurisdictions for
methods of identifying and treating patients with the beta-1 389 arginine
homozygous genotype. The Company plans to conduct a Phase 3 clinical trial to
evaluate Gencaro as a potential treatment for the prevention of AF in patients
with this genotype, subject to receiving the necessary funding.

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 atrial fibrillation.
ARCA has identified common genetic variations that it believes predict
individual patient response to Gencaro, giving it the potential to be the
first genetically-targeted atrial fibrillation prevention treatment. ARCA has
a collaboration with the Laboratory Corporation of America (LabCorp), under
which LabCorp has developed a companion genetic test for Gencaro. For more
information please visit www.arcabiopharma.com.

Safe Harbor Statement

This press release and the associated presentation may contain
"forward-looking statements" for purposes of the safe harbor provided by the
Private Securities Litigation Reform Act of 1995. These statements include,
but are not limited to, statements regarding the ability of genetic variations
to predict individual patient response to Gencaro, Gencaro’s potential to
treat atrial fibrillation, and the potential for Gencaro to be the first
genetically-targeted atrial fibrillation prevention treatment. Such statements
are based on management's current expectations and involve risks and
uncertainties. Actual results and performance could differ materially from
those projected in the forward-looking statements as a result of many factors,
including, without limitation, the risks and uncertainties associated with:
the Company's financial resources and whether they will be sufficient to meet
the Company's business objectives and operational requirements; results of
earlier clinical trials may not be confirmed in future trials, the protection
and market exclusivity provided by the Company’s intellectual property; risks
related to the drug discovery and the regulatory approval process; and, the
impact of competitive products and technological changes. These and other
factors are identified and described in more detail in ARCA’s filings with the
SEC, including without limitation the Company’s annual report on Form 10-K for
the year ended December 31, 2011 and subsequent filings. The Company disclaims
any intent or obligation to update these forward-looking statements.

Contact:

ARCA biopharma, Inc.
Christopher D. Ozeroff
Senior Vice President and General Counsel
720-940-2100