Westminster, CO, November 5, 2015 – ARCA biopharma, Inc. (Nasdaq: ABIO), a biopharmaceutical company developing genetically-targeted therapies for cardiovascular diseases, today announced that its President and CEO, Michael R. Bristow, M.D., Ph.D., will give two invited presentations at the American Heart Association Scientific Sessions 2015 (http://my.americanheart.org/professional/Sessions/ScientificSessions/Scientific-Sessions_UCM_316900_SubHomePage.jsp)being held November 7-11, 2015 in Orlando, Florida.

The session “Emerging Pharmacological Approaches to Treat Heart Failure” will be held Sunday, November 8, 2015. Dr. Bristow will present “GPCR Polymorphisms driving heart failure therapeutic outcomes” at 8:00am ET.

The session “Phenotyping Heart Failure: Is this the Way Forward?” will be held Sunday, November 8, 2015. Dr. Bristow will present “Phenotyping Heart Failure Helpful New Tool?” at 9:00am ET.

ARCA is currently developing GencaroTM (bucindolol hydrochloride) as a potential treatment for atrial fibrillation in a genotype-defined heart failure population (heart failure patients with reduced left ventricular ejection fraction, HFREF). Earlier this year, the Gencaro development program was designated a Fast Track development program by the U.S. Food and Drug Administration. The Phase 2B/3 GENETIC-AF trial is currently recruiting patients at clinical trial sites in the
United States and Canada.

Atrial Fibrillation (AF)

Atrial fibrillation, the most common sustained cardiac arrhythmia, is considered an epidemic cardiovascular disease and a major public health burden. The estimated number of individuals with AF globally in 2010 was 33.5 million. According to the 2015 American Heart Association report on Heart Disease and Stroke Statistics, the estimated number of individuals with AF in the United States in 2010 ranged from 2.7 million to 6.1 million people. Hospitalization rates for AF
increased by 23% among U.S. adults from 2000 to 2010 and hospitalizations account for the majority of the economic cost burden associated with AF.

About ARCA biopharma

ARCA biopharma is dedicated to developing genetically-targeted therapies for cardiovascular diseases. The Company’s lead product candidate, GencaroTM  (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 Medtronic, Inc. for support of the GENETIC-AF trial.  For more information please visit
www.arcabiopharma.com.

Safe Harbor Statement

This press release contains “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, potential timeline for GENETIC-AF trial activities, the potential for genetic variations to predict individual patient response to Gencaro, Gencaro’s potential to treat atrial fibrillation, future treatment options for patients with 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, 2014, and subsequent filings. The Company disclaims any intent or obligation to update these forward-looking statements.

Investor & Media Contact:
Derek Cole 720.940.2163
derek.cole@arcabiopharma.com
###

The Paper, Which Describes Pharmacogenetic Enhancement of Effectiveness for Prevention of Atrial Flutter, Was Also Published in the Journal of Cardiac Failure

Westminster, CO, September 9, 2015 – ARCA biopharma, Inc. (Nasdaq: ABIO), a biopharmaceutical company developing genetically-targeted therapies for cardiovascular diseases, today announced that the paper “Bucindolol Prevents Atrial Flutter via the Beta-1 389 Arg/Gly Adrenergic Receptor Polymorphism” will be presented at the 19th annual Scientific Meeting of the Heart Failure Society of America (HFSA) to be held in Washington, D.C. September 26-29, 2015. The paper was recently published in the Journal of Cardiac Failure http://www.onlinejcf.com/article/S1071-9164(15)00366-8/fulltext, the official journal of the Heart Failure Society of America and the Japanese Heart Failure Society. The lead author on the paper is cardiologist-electrophysiologist Ryan G. Aleong of the University of Colorado, Anschutz Medical Campus, and a co-author on the paper is Dr. Michael R. Bristow, the Company’s Chief Executive Officer.

Based on prior data from the Beta-Blocker Evaluation of Survival Trial (BEST) which suggested that Gencaro (bucindolol hydrochloride) decreased incident atrial fibrillation (AF) in patients with heart failure with reduced left ventricular ejection fraction (HFREF), the authors sought to investigate whether bucindolol prevented atrial flutter (AFL) to the same degree as AF in BEST. The author’s retrospective analysis was performed on data from BEST, which enrolled 2,708 NYHA class III or IV patients and included a 1,040 patient DNA substudy that genotyped patients for the β1 -AR 389 Arg/Gly polymorphism.

The author’s results indicated that in BEST there were 17 patients with AFL and 303 patients with AF on their pre-randomization baseline electrocardiogram (ECG). In patients with baseline AFL, bucindolol was associated with a higher rate of reversion to sinus rhythm compared to placebo (bucindolol 8/9 (89%) vs. placebo 2/8 (25%); p = 0.0075). In patients who entered the trial not in AF or AFL, there were a total of 45 incident episodes of AFL during the trial, with fewer new onset AFL cases in the bucindolol group [bucindolol 17/1193 (1.4%) vs. Placebo 28/1182 (2.4%); HR = 0.55 (95% CI 0.30, 1.01)]. This prevention of AFL was similar to previous reports of AF prevention by bucindolol and, therefore, AF and AFL were grouped into one endpoint (AFL/AF). There was significantly less new onset AFL/AF with bucindolol compared to placebo [bucindolol 88/1193 (7.4%) vs. placebo 137/1182 (11.6%); HR 0.58 (95% CI 0.45, 0.76)]. In the BEST DNA substudy, prevention of AFL/AF was observed exclusively in the β1 Arg/Arg subgroup [HR 0.29(0.14,0.60)] compared to the β1 Gly carrier group [HR 0.91 (0.53, 1.56)] with a significant interaction between the genotype and treatment (p = 0.019).

The authors concluded: “Bucindolol appears to prevent atrial flutter to a similar degree and by a similar mechanism as atrial fibrillation and, therefore, grouping atrial flutter with atrial fibrillation appears to be a legitimate endpoint in HFREF AF prevention trials.”

Atrial Flutter (AFL)

Atrial flutter is the second most common abnormal heart rhythm, or tachyarrhythmia, after atrial fibrillation. The condition is a type of supraventricular (above the ventricles) tachycardia (rapid heartbeat). In AFL, the upper chambers, or atria, of the heart beat too fast, which results in atrial muscle contractions that are faster than and out of sync with the lower chambers, or ventricles. AFL itself is not life threatening. If left untreated, the side effects of AFL can be potentially life threatening. Without treatment, AFL can also cause another type of arrhythmia called atrial fibrillation, the most common type of abnormal heart rhythm. Approximately 200,000 new cases of atrial flutter are estimated to be diagnosed in the United States each year.

About ARCA biopharma

ARCA biopharma is dedicated to developing genetically-targeted therapies for cardiovascular diseases. The Company’s lead product candidate, Gencaro (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 Medtronic, Inc. for support of the GENETIC-AF trial. For more information please visit www.arcabiopharma.com.

Safe Harbor Statement

This press release contains “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, potential timing for patient enrollment in the GENETIC-AF trial, potential timeline for GENETIC-AF trial activities, the sufficiency of the Company’s capital to support its operations, the potential for genetic variations to predict individual patient response to Gencaro, Gencaro’s potential to treat atrial fibrillation, Gencaro’s potential efficacy in treating atrial flutter, future treatment options for patients with atrial fibrillation or atrial flutter, 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, 2014, and subsequent filings. The Company disclaims any intent or obligation to update these forward-looking statements.

Investor & Media Contact:

Derek Cole

720.940.2163

derek.cole@arcabiopharma.com

###

Phase 2B of GENETIC-AF Projected to Complete Enrollment by Year-End 2016

Westminster, CO, August 11, 2015 – ARCA biopharma, Inc. (Nasdaq: ABIO), a biopharmaceutical company developing genetically-targeted therapies for cardiovascular diseases, today reported financial results for the quarter ended June 30, 2015, and provided an update on recent accomplishments.

“This quarter was productive for ARCA. We strengthened our financial position through a successful equity offering that resulted in net proceeds of approximately $34 million, which we believe will fund the Company through completion of enrollment in the Phase 2B portion of GENETIC-AF and the interim analysis determination to potentially advance the trial to the pivotal Phase 3 portion,” said Dr. Michael Bristow, ARCA’s President and CEO. “We also implemented a protocol amendment for GENETIC-AF, which expanded the target population, both clinically and commercially.”

Second Quarter 2015 Summary Financial Results

Cash and cash equivalents totaled $44.1 million as of June 30, 2015, compared to $15.4 million as of December 31, 2014. The Company believes that its current cash and cash equivalents will be sufficient to fund its operations, at its projected cost structure, through at least the end of 2017. ARCA had 63.2 million outstanding shares of common stock as of August 7, 2015.

Research and development (R&D) expenses for the three months ended June 30, 2015 were $1.7 million compared to $1.4 million for the corresponding period of 2014, an increase of approximately $0.3 million. R&D expenses for the six months ended June 30, 2015 were $3.5 million compared to $2.7 million for the corresponding period of 2014, an increase of approximately $0.7 million. The increase in R&D expenses in the three and six month periods ended June 30, 2015 is due, primarily, to the increased clinical expense of the GENETIC-AF clinical trial. The Company expects R&D expenses in 2015 to be higher than 2014 as it activates new clinical sites and enrolls additional patients in the GENETIC-AF clinical trial and incurs incremental costs associated with transitioning to the protocol amended in the first quarter of 2015.

General and administrative (G&A) expenses for the three months ended June 30, 2015 were $1.0 million compared to $1.0 million for the corresponding period in 2014. G&A expenses for the six months ended June 30, 2015 were $2.0 million compared to $2.1 million for the corresponding period in 2014.

Total operating expenses for the three months ended June 30, 2015 were $2.7 million compared to $2.4 million for the corresponding period in 2014. Total operating expenses for the six months ended June 30, 2015 were $5.5 million compared to $4.8 million for the corresponding period in 2014.

Net loss was $2.7 million, or $0.10 per share, for the second quarter of 2015 and $5.5 million, or $0.22, for the six months ended June 30, 2015, compared to $2.4 million, or $0.11, for the second quarter of 2014 and $4.8 million, or $0.24, for the six months ended June 30, 2014.

Key Accomplishments

• During the quarter, the Company implemented a previously announced protocol amendment for GENETIC-AF, which expanded the trial’s target population. The Company previously met with the U.S. Food and Drug Administration to confirm the acceptability of the amendments to the protocol and received no objections.
• In May, the Company hosted an Investigator Meeting and Training conference attended by 81 physicians and clinical trial coordinators representing 54 trial sites.
• During the quarter, existing investigative clinical sites were approved, trained and began adopting the revised protocol, with the majority of the Company’s active clinical sites now operating under the revised protocol.
• In June, the Company completed an equity financing with institutional investors, raising net proceeds of approximately $34 million.

There are currently 52 active clinical trial sites in the United States and Canada. The Company anticipates that the trial will enroll patients at approximately 65 sites for the Phase 2B portion of GENETIC-AF. The trial is projected to complete enrollment of 200 patients in the Phase 2B portion of the trial by the end of 2016. The Company plans to provide trial enrollment updates as each quarter of the targeted 200 patients is enrolled. While the protocol changes have begun to be adopted by clinical sites, it is too early to determine the impact of the amendments on enrollment or whether the Company’s enrollment projections will prove to be accurate.

“We greatly appreciate the support and feedback from the clinical investigator community participating in GENETIC-AF,” said Dr. Christopher Dufton, Vice President, Clinical Development of ARCA. “In addition to the investigators’ enthusiasm for the trial, we are pleased to see an increase in study screening activities that has coincided with implementation of the revised protocol. It is also encouraging to see that the eligibility rates for the study, including those for the targeted genotype (~50%), have generally been consistent with our pre-trial assumptions and study design. We look forward to the continued progress of GENETIC-AF and sharing future updates.”

GENETIC-AF Trial Phase 2B Projected Timeline

 Revised protocol distributed to participating clinical trial sites March 2015

 GENETIC-AF Trial Investigators meeting and training May

 First trial sites operating under revised protocol May (June)

– Approximately 65 clinical trial sites active in U.S. & Canada Q4 2015

– Completion of Enrollment of 200 Patients YE 2016

– DSMB Interim Analysis Decision 1H 2017

The Company’s forecast of the time periods to achieve these milestones is a forward-looking statement and involves risks and uncertainties, and actual results are likely to vary as a result of a number of factors, including the factors discussed in “Risk Factors” in the Company’s periodic SEC filings.

GENETIC-AF Clinical Trial

GENETIC-AF is a Phase 2B/3, multi-center, randomized, double-blind clinical trial comparing the safety and efficacy of Gencaro to Toprol-XL (metoprolol succinate) for the treatment of atrial fibrillation (AF) in patients with heart failure and left ventricular systolic dysfunction (HFREF patients). The primary endpoint of GENETIC-AF is time to symptomatic AF/atrial flutter (AFL). ARCA is enrolling only HFREF patients with the genetic variant of the cardiac beta-1 adrenergic receptor, which the Company believes responds most favorably to Gencaro, the 389 arginine homozygous genotype (ADRB1 Arg389Arg). GENETIC-AF has an adaptive design, under which the Company initiated the trial as a Phase 2B trial seeking to enroll approximately 200 patients. The GENETIC-AF Data Safety Monitoring Board (DSMB) will analyze certain data from the Phase 2B portion of the trial and recommend, based on a comparison to the pre-trial statistical assumptions, whether the trial should proceed to Phase 3 and seek to enroll an additional 420 patients.

Atrial Fibrillation (AF)

Atrial fibrillation, the most common sustained cardiac arrhythmia, is considered an epidemic cardiovascular disease and a major public health burden. The estimated number of individuals with AF globally in 2010 was 33.5 million. According to the 2015 American Heart Association report on Heart Disease and Stroke Statistics, the estimated number of individuals with AF in the U.S. in 2010 ranged from 2.7 million to 6.1 million people. Hospitalization rates for AF increased by 23% among US adults from 2000 to 2010 and hospitalizations account for the majority of the economic cost burden associated with AF.

About ARCA biopharma

ARCA biopharma is dedicated to developing genetically-targeted therapies for cardiovascular diseases. The Company’s lead product candidate, GencaroTM (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 Medtronic, Inc. for support of the GENETIC-AF trial. For more information please visit www.arcabiopharma.com.

Safe Harbor Statement

This press release contains “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, potential timing for patient enrollment in the GENETIC-AF trial, potential timeline for GENETIC-AF trial activities, the sufficiency of the Company’s capital to support its operations, the potential for genetic variations to predict individual patient response to Gencaro, Gencaro’s potential to treat atrial fibrillation, future treatment options for patients with 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, 2014, and subsequent filings. The Company disclaims any intent or obligation to update these forward-looking statements.

Investor & Media Contact:

Derek Cole

720.940.2163

derek.cole@arcabiopharma.com

###

(Tables Follow)

ARCA BIOPHARMA, INC.

BALANCE SHEET DATA

(in thousands)

Proceeds to Support Advancement of Bucindolol Phase 2B/3 Clinical Development

Bucindolol potentially the first genetically-targeted atrial fibrillation prevention treatment

Westminster, CO, June 17, 2015 – ARCA biopharma, Inc. (Nasdaq: ABIO), a biopharmaceutical company developing genetically-targeted therapies for cardiovascular diseases, today announced the closing of the previously announced private placement financing with a select group of institutional investors, including lead investor Venrock, New Enterprise Associates (NEA), funds managed by Franklin Advisers, Inc., RA Capital Management, Tekla Life Sciences Investors and other institutional investors. ARCA received net proceeds of approximately $34 million from the sale of approximately 42 million units at a price of $0.8805 per unit. Each unit consists of one share of ARCA’s common stock and a warrant to purchase 0.40 shares of common stock with an exercise price of $0.8716. The warrants have a term of seven years and become exercisable 180-days after the closing date.

ARCA plans to use the anticipated proceeds from the private placement for working capital and clinical development of bucindolol, including GENETIC-AF, the ongoing Phase 2B/3 trial for the prevention of atrial fibrillation. The Company anticipates that its current cash and cash equivalents and the net proceeds of this private placement will be sufficient to fund its operations, at the projected cost structure, through the end of 2017. However, changing circumstances may cause the Company to consume capital significantly faster or slower than currently anticipated.

MTS Securities, LLC, an affiliate of MTS Health Partners, acted as sole placement agent in the transaction.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such jurisdiction.

The securities sold in the private placement have not been registered under the Securities Act of 1933, as amended, or state securities laws and may not be offered or sold in the United States absent registration with the Securities and Exchange Commission (SEC) or an applicable exemption from such registration requirements. ARCA has agreed to file a registration statement with the SEC covering the resale of the shares of common stock, including the shares of common stock issuable upon exercise of the warrants, sold in the private placement.

About ARCA biopharma

ARCA biopharma is dedicated to developing genetically-targeted therapies for cardiovascular diseases. The Company’s lead product candidate, bucindolol, 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 bucindolol, giving it the potential to be the first genetically-targeted atrial fibrillation prevention treatment. ARCA has a collaboration with Medtronic, Inc. for support of the GENETIC-AF trial. The U.S. Food and Drug Administration (FDA) has designated as a Fast Track development program the investigation of bucindolol for the prevention of atrial fibrillation/atrial flutter in a genetically-targeted heart failure population (heart failure patients with reduced left ventricular ejection fraction, HFREF). For more information please visit www.arcabiopharma.com.

Safe Harbor Statement

This press release contains “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, sufficiency of the Company’s capital to support its operations, potential timeline for GENETIC-AF trial activities, the potential for genetic variations to predict individual patient response to bucindolol, bucindolol’s potential to treat atrial fibrillation, future treatment options for patients with atrial fibrillation, and the potential for bucindolol 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, 2014, and subsequent filings. The Company disclaims any intent or obligation to update these forward-looking statements.

Investor & Media Contact:

Derek Cole

720.940.2163

derek.cole@arcabiopharma.com

###