Filed by Nuvelo, Inc. Pursuant to Rule 425

Under the Securities Act of 1933

And Deemed Filed Pursuant to Rule 14a-12

Under the Securities Exchange Act of 1934

Subject Company: ARCA biopharma, Inc.

Commission File No. 333-154839

The following is a presentation made by ARCA biopharma, Inc. and Nuvelo, Inc. beginning on January 12, 2009.

J.P. Morgan 27 th Annual Healthcare Conference January 12 – 15, 2009

Safe Harbor Statement 2 This presentation contains “forward-looking statements” which include, without limitation, statements regarding the completion of the proposed merger transaction between Nuvelo, Inc., ARCA biopharma, Inc. and Dawn Acquisition Sub, Inc. the proposed merger’s anticipated benefits, timing, progress and anticipated completion of the companies’ clinical stage and research programs, the timing of regulatory approval, the potential benefits that patients may experience from the use of the companies’ clinical stage compounds, and the cash position of the companies following the merger, which statements are hereby identified as “forward-looking statements” for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. Such statements are based on the companies’ managements’ 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, failure to complete the proposed merger in a timely fashion, the risk that Nuvelo’s and ARCA’s business operations will not be integrated successfully; the companies’ inabilities to further identify, develop and achieve commercial success for products and technologies; the risk that the companies’ financial resources will be insufficient to meet their business objectives; uncertainties relating to drug discovery and the regulatory approval process; clinical development processes; enrollment rates for patients in the companies’ clinical trials; changes in relationships with strategic partners and dependence upon strategic partners for the performance of critical activities under collaborative agreements; and the impact of competitive products and technological changes. These and other factors are identified and described in more detail in Nuvelo’s filings with the SEC, including without limitation Nuvelo’s quarterly report on Form 10-Q for the quarter ended September 30, 2008 and subsequent filings. Nuvelo and ARCA disclaim any intent or obligation to update these forward-looking statements.

Introducing: ARCA biopharma* 3 Pioneering Genetically-Targeted Cardiovascular Therapies *ARCA,  Nuvelo merger is expected to be completed in 1/2009

Multiple Near & Long Term Value Creating Aspects 4

Value-Driving Near-Term Milestones Milestone Expected Timing NDA acceptance by FDA H2:08 • Completion of merger 1/2009 • LabCorp PMA submission to FDA for Gencaro genetic test Q1:09 • Anticipated FDA CRAC meeting H1:09 • FDA decision on Gencaro PDUFA Date: 5/31/09 • Anticipated launch of genetic registry post approval Q3:09 • Potential launch of Gencaro Q1:10 or Q4:09 5

Introducing Gencaro™* (bucindolol hydrochloride) Investigational drug currently under FDA review Next-generation beta-blocker with unique pharmacology Potentially first genetically-targeted heart failure drug – Companion genetic test being developed by LabCorp Potential to target ~50% of heart failure (HF) patients – ‘Very Favorable’ genotype is target patient population for treatment Potential follow-on indications – Potential prevention of atrial fibrillation and/or ventricular tachycardia/ventricular fibrillation being explored * Trade name pending FDA approval 6

Genetic Basis of Gencaro Response Mediated Through Individual Genetic Variation 7 Cardiac myocyte “Arg/Arg” 1 389 AR” •Better bucindolol antagonism – increased survival – reduced hospitalization •Very favorable receptor type “Gly Variant” 1 389 AR •Standard bucindolol antagonism • Adverse when combined with 2c Del genotypes “WT” 2c AR” •Mild, ideal NE lowering with bucindolol •Favorable receptor type when combined with 1 389 Gly genotypes “Deletion Variant” 2c AR •Marked NE lowering with bucindolol •Adverse receptor type when combined with 1 389 Gly genotypes

BEST: Clinical Responses by Genotypes  *p<0.05; **p<0.007 Endpoint Very Favorable Genotype (47%) {ß 1 389 Arg/Arg + any a 2C } Favorable Genotype (40%) {ß 1 389 Gly carrier + a 2C Wt/Wt} Unfavorable Genotype (13%) {ß 1 389 Gly carrier + a 2C Del carrier} AC Mortality (ACM), Time-to-Event (TTE) 38% * 25% 4% CV Mortality, (CVM), TTE 48% * 40%* 11% HF Progression, TTE † 34% ** 20% 1% HF Hosp/pt 43% * 16% 26% HF Hosp days/pt 48% ** 17% 19% † Composite endpoint consisting of: HF mortality, cardiac transplant, HF hospitalizations, and HF emergency room visits 8

Bucindolol n = 2708 Metoprolol n = 1071 Carvedilol n = 482 Bucindolol (VF Genotype) n = 493 Metoprolol n = 3991 Carvedilol n = 2289 Trial Name BEST MERIT COPERNICUS BEST MERIT COPERNICUS Trial Location US US US US WW WW All-cause Mortality -13% +5% -20% -38% -34% -35% CV Mortality -16% -4% -48% -38% No Data Mortality + Cardiac Transplant -14% -43% -32% No Data Mortality & HF Hospitalizations -21% -16% -35% -31% -33% HF Hospitalizations, TTE -23% No Data -36% NA No Data HF hospitalization days -24% No Data -48% -36% -41% Total MI in HF Patients -45-47% No Data -48% No Data No Data Comparison of Beta–blocker Studies*: US & ROW 9 *  Not head-to-head studies

Marketing Research: Gencaro Demand • > 600 cardiologists with established HF practices interviewed or surveyed to date • Demand for Gencaro is anticipated to be strong – Peak genetic test ordering opportunity for targeted patient population segments • >60% of beta-blocker naïve HF patients • >60% of HF patients that are difficult to titrate or have been deemed non-responsive to existing beta-blocking agents • Cardiologists expected to value Gencaro’s: – Improvement in clinical outcomes – Ability to predict response 10 † ARCA Primary Market Research; 11/2008 †

LabCorp Relationship • Easy-to-administer genetic test • Quick turnaround time for results expected • Test results will identify genetic markers that predict clinical response • 510K/PMA track within FDA – Coordinated with Gencaro NDA 11

Established, Large Market Opportunity Beta-blockers = current standard of care in chronic heart failure – “Beta-blockers should be prescribed to all patients with stable HF due to reduced LVEF …” (ACC/AHA Guidelines 2005) ~6 million US HF patients ~550K newly diagnosed patients annually 12

Commercial Strategy • Cardiologists initiate and influence beta-blocker prescriptions • Penetrate U.S. market with specialized sales force • Unique and desirable offering in large market – Expected to be only drug with companion test to predict response • Defend market exclusivity – Hatch-Waxman protection until 2017 – Potential patent protection until 2025 13

Competitive Environment Limited Competitive Threats • Current beta blockers have generic equivalents on the market • Promotion is very limited • Known future competitors do not have a companion genetic test or any known PGt interactions 14

Pricing and Reimbursement • While majority of HF patients are Part D eligible, most opt for supplemental commercial prescription coverage • Current branded beta-blocker products range from $2.54 - $4.74 /day (AWP) – Gencaro expected to be on formulary with reasonable pricing • Test anticipated to be covered via medical benefit; Part B for Medicare patients 15

Gencaro US Approval Process • FDA filed New Drug Application – 9/28/08 • Clinical site inspections proceeding • FDA Pre-Approval Inspection of manufacturer scheduled • Regulatory department actively communicating with the agency • FDA’s 2009 performance goal: Review and act on 90% of NDAs by PDUFA date 16

NDA submission to the FDA: 7/31/08 Potential FDA Cardio-Renal Advisory Committee  (CRAC) meeting Potential commercial launch PDUFA Date: 5/31/09 FDA NDA filing: 9/28/08 2008 2009 2010 Gencaro Pathway to Market 17 LabCorp PMA submission to the FDA for complementary genetic test

Value-Driving Near-Term Milestones Milestone Expected Timing NDA acceptance by FDA H2:08 • Completion of merger 1/2009 • LabCorp PMA submission to FDA for Gencaro genetic test Q1:09 • Anticipated FDA CRAC meeting H1:09 • FDA decision on Gencaro PDUFA Date: 5/31/09 • Anticipated launch of genetic registry post approval Q3:09 • Potential launch of Gencaro Q1:10 or Q4:09 18

Personalized Medicine: Recently in the News 19

THANK YOU

Additional Information and Where to Find It • Nuvelo has filed a registration statement on Form S-4, and a related proxy statement/prospectus/consent solicitation, in connection with the merger. Investors and security holders are urged to read the registration statement on Form S-4 and the related proxy statement/prospectus/consent solicitation which contain important information about the merger transaction. Investors and security holders may obtain free copies of these documents and other documents filed with the SEC at the SEC’s website at www.sec.gov. In addition, investors and security holders may obtain free copies of the documents filed with the SEC by contacting Nuvelo Investor Relations at the email address: ir@nuvelo.com or by phone at 650-517-8000. • In addition to the registration statement and related proxy statement/prospectus/consent solicitation, Nuvelo files annual, quarterly and special reports, proxy statements and other information with the SEC. You may read and copy any reports, statements or other information filed by Nuvelo, Inc. at the SEC public reference room at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for more information. Please call the SEC at 1-800-SEC-0330 for further information on the public reference room. Nuvelo, Inc.’s filings with the SEC are also available to the public from commercial document-retrieval services and at SEC’s website at www.sec.gov, and from Investor Relations at Nuvelo as described above. • This communication shall not constitute an offer to sell or the solicitation of an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offering of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended. • Nuvelo, ARCA and their respective directors and executive officers may be deemed to be participants in the solicitation of proxies from the stockholders of Nuvelo in connection with the merger transaction. Information regarding the special interests of these directors and executive officers in the merger transaction is included in the proxy statement/prospectus/consent solicitation described above. Additional information regarding the directors and executive officers of Nuvelo is also included in Nuvelo’s proxy statement for its 2008 Annual Meeting of Stockholders which was filed with the SEC on April 23, 2008 and its Annual Report on Form 10-K for the year ended December 31, 2007, which was filed with the SEC on March 12, 2008. These documents are available as described above. 21