UPDATE 1-Arca reaches agreement with FDA on heart-drug study

* To do study in 3200 heart patients with specific genotype

* Sees starting the trial in H2 2011

* Shares up as much as 32 pct

May 17 (Reuters) - Arca Biopharma Inc (ABIO.O) said it reached an agreement with the U.S. health regulator on the design of a trial to test its experimental treatment for heart failure, sending its shares soaring 32 percent.

According to a special protocol assessment agreement, the drug, bucindolol, will be evaluated in a trial that plans to enroll 3,200 patients with chronic heart failure who have the specific genotype that appears to respond most favorably to the drug.

The special protocol assessment provides a company with a written agreement that the design and analysis of the trial are adequate to support a marketing application submission with the U.S. health regulator.

The main goal of the planned trial, which will compare bucindolol with an approved heart-failure drug, metoprolol CR/XL, is to look at a composite of cardiovascular mortality and cardiovascular hospitalization.

Arca, which received a complete response letter from the U.S. Food and Drug Administration in June 2009 saying a late-stage trial of the drug did not adequately demonstrate its efficacy, expects to begin the proposed trial in the second half of 2011.

Shares of the company were up 27 percent to $5.42 in morning trade on Nasdaq. They reached a high of $5.63 earlier in the session. (Reporting by Esha Dey in Bangalore; Editing by Prem Udayabhanu)