ARCA BIOPHARMA, INC.
STOCK OPTION AGREEMENT
ARCA biopharma, Inc. (f/k/a Nuvelo, Inc.) has granted to the individual (the “ Optionee ” ) named in the Notice of Grant of
Stock Option (the “ Notice ” ) to which this Stock Option Agreement (the “ Option Agreement ” ) is attached an option (the “
Option ” ) to purchase certain shares of Stock upon the terms and conditions set forth in the Notice and this Option
Agreement. The Option has been granted pursuant to and shall in all respects be subject to the terms and conditions of the
Nuvelo, Inc. 2004 Equity Incentive Plan (the “ Plan ” ), as amended to the Date of Option Grant, the provisions of which are
incorporated herein by reference. By signing the Notice, the Optionee: (a) represents that the Optionee has read and is familiar
with the terms and conditions of the Notice, the Plan and this Option Agreement, including the Effect of Termination of Service
set forth in Section 7, (b) accepts the Option subject to all of the terms and conditions of the Notice, the Plan and this Option
Agreement, (c) agrees to accept as binding, conclusive and final all decisions or interpretations of the Board upon any
questions arising under the Notice, the Plan or this Option Agreement, and (d) acknowledges receipt of a copy of the Notice,
the Plan and this Option Agreement.
1. D EFINITIONS A ND C ONSTRUCTION .
1.1 Definitions . Unless otherwise defined herein, capitalized terms shall have the meanings assigned to such terms in
the Notice or the Plan.
1.2 Construction . Captions and titles contained herein are for convenience only and shall not affect the meaning or
interpretation of any provision of this Option Agreement. Except when otherwise indicated by the context, the singular shall
include the plural and the plural shall include the singular. Use of the term “or” is not intended to be exclusive, unless the
context clearly requires otherwise.
2. T AX C ONSEQUENCES .
2.1 Tax Status of Option . This Option is intended to have the ta