About Special Protocol Assessment (SPA)

An SPA is an agreement with the FDA that the proposed trial protocol design, clinical endpoints and statistical analyses are acceptable to support regulatory approval. For further information regarding the SPA process, please visit the FDA website, www.fda.gov. An SPA agreement is not a guarantee of approval, and there are no assurances that the design of, or data collected from, the planned bucindolol clinical trial will be adequate to obtain the requisite regulatory approvals for the marketing of bucindolol.

About Bucindolol

Bucindolol hydrochloride is a pharmacologically unique beta-blocker and mild vasodilator being developed for the treatment of chronic heart failure (HF). Bucindolol is an oral tablet formulation, dosed twice daily. Bucindolol is considered part of the beta-blocker class because of its property of blocking beta-1 as well as beta-2 receptors in the heart, preventing these receptors from binding with other molecules that would otherwise activate the receptor. Clinical data to date suggest that bucindolol is well-tolerated in patients with advanced HF, which the Company believes is due to bucindolol’s mild vasodilator effects.

About Heart Failure

Heart failure, or HF, is a chronic, progressive condition in which a problem with the structure or function of the heart impairs its ability to supply sufficient blood flow to the meet the body’s needs for blood and oxygen. Common causes of heart failure include myocardial infarction and other forms of ischemic heart disease, hypertension, valvular heart disease and cardiomyopathy. Heart failure is one of the largest health care problems in the United States and the rest of the world. Industry sources estimate that about 5.7 million Americans have HF and nearly 670,000 new patients are diagnosed annually. In addition, HF is the underlying reason for approximately 12 to 15 million annual visits to physicians, 6.5 million annual hospital days and over $37 billion in direct and indirect annual healthcare costs.

Beta-blockers are part of the current standard of care for HF, and are considered to be among the most effective drug classes for the disease. However, a significant percentage of eligible patients in the United States is not being treated with, or does not tolerate or respond well to, the beta-blockers currently approved for the treatment of HF. ARCA believes that new therapies for which patient response can be predicted before a drug is prescribed can help improve the current standard of practice in the treatment of HF.