ARCA biopharma, Inc. notified The NASDAQ Stock Market LLC (NASDAQ) on May 6, 2013 of Dr. Sobel’s death, member of the board of directors. As a result of his death, ARCA no longer has at least three audit committee members, as required by NASDAQ Listing Rule 5605(c)(2)(A). Consistent with the cure period provided in NASDAQ Listing Rule 5605(c)(4)(B), ARCA expects to cure this deficiency before the earlier of the Company’s next annual stockholders’ meeting or May 2, 2014.

ARCA biopharma, Inc. announced that Burton E. Sobel, 75, a member of its board of directors, has died.

ARCA biopharma, Inc. announced that it has entered into an agreement with Medtronic, Inc. to improve the treatment of chronic diseases, including cardiac rhythm disorders, to collaborate on ARCA's proposed clinical trial, known as GENETIC-AF, of its lead developmental drug Gencaro (bucindolol hydrochloride). GENETIC-AF is planned as a Phase 2b/3 clinical trial comparing Gencaro to metoprolol CR/XL for prevention of atrial fibrillation ("AF") in patients with heart failure and reduced left ventricular ejection fraction (HFREF). ARCA plans to enroll only patients with the genetic variant of the beta-1 cardiac receptor which the Company believes responds most favorably to Gencaro. GENETIC-AF has an adaptive design, under which the Company plans to initiate it as a Phase 2b study in approximately 200 patients and then, depending on the results of an interim analysis, expand the trial to a Phase 3 study by enrolling an estimated additional 420 patients. Under the collaboration, ARCA plans, with the support of Medtronic, to conduct a substudy that will include continuous monitoring of the cardiac rhythms of all 200 patients enrolled during the Phase 2b portion of GENETIC-AF. Each patient will have heart rhythm monitoring via a Medtronic device, either a previously implanted cardiac resynchronization or defibrillation device, or a previously or newly inserted Reveal(R) loop recorder. The collaboration substudy will measure AF burden, defined as a patient's actual time in AF regardless of symptoms. In determining the presence of an efficacy signal in the Phase 2b portion of the trial, AF burden will be evaluated along with time to mortality or recurrent AF, which will also be the Phase 3 primary endpoint.