Exhibit 10.63

SUNESIS PHARMACEUTICALS, INC.

2009 BONUS PROGRAM

Overview

The 2009 Bonus Program (the “Program”) of Sunesis Pharmaceuticals, Inc. (the
“Company”) was adopted effective May 8, 2009 (the “Effective Date”). The Program
is designed to motivate, retain and reward Company employees through a
combination of corporate and individual performance-based incentive compensation
components during the period commencing on the Effective Date and ending on
March 31, 2010 (the “Performance Period”). Individuals employed by the Company
during the Performance Period who are designated for participation by the
Compensation Committee of the Company’s Board of Directors (the “Committee”) and
who remain employed by the Company through the Payment Date (as defined below)
(each a “Participant”) shall be eligible to earn a bonus under the Program. The
Program is administered by the Committee, and any decisions made in good faith
by the Committee shall be final and binding on all Participants and interested
parties.

The Program is designed to award a cash bonus payment (each a “Cash Bonus”) for
performance during the Performance Period to Participants based in part on the
level of achievement (1) by the Company of certain Company-wide objectives (the
“Corporate Objectives”) and (2) by the Participant of certain individual
performance objectives, which may include certain department, group and/or team
objectives applicable to such Participant (the “Individual Objectives”). The
Committee may require that certain objectives be achieved prior to the end of
the Performance Period (e.g., such as achievement not later than December 31,
2009) in order to be eligible to qualify for payment of the Cash Bonus.

Program Objectives

The Program is intended to encourage and reward the following:

 

  •  

the achievement of Corporate Objectives,

 

  •  

the achievement of Individual Objectives,

as well as to recognize individual contributions and effort.

Determination of Program Objectives

The Corporate Objectives shall be approved by the Board of Directors, with input
from the Committee, management, and generally relate to the achievement of
certain research, clinical development, business development, financial,
business and similar milestones. Each Corporate Objective is assigned a relative
weighting from the Board of Directors, reflecting its importance to the
achievement of the Company’s key results during the Performance Period;
provided, however, the Board of Directors or the Committee may adjust the
weighting of the Corporate Objectives in its sole discretion at any time.

In addition, the Committee has selected, as a threshold Corporate Objective, the
closing of a financing or corporate transaction that provides at least $20
million of net proceeds (a “Qualifying Transaction”) on or before March 31,
2010. If a Qualifying Transaction does not occur prior to the conclusion of the
Performance Period, no Cash Bonuses will be earned under the Program.

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The Individual Objectives shall be set as follows:

 

  •  

For the Chief Executive Officer, the Individual Objectives shall be set by the
Committee;

 

  •  

For Participants who are executive officers (as that term is defined under
Section 16 of the Securities Exchange Act of 1934, as amended, and Rule 16a-1
thereunder), other than the Chief Executive Officer (collectively, the
“Executive Participants”), the Individual Objectives shall be set by the
Committee based upon recommendations made by the Chief Executive Officer; and

 

  •  

For non-Executive Participants (collectively, the “Non-Executive Participants”),
the Individual Objectives shall be set by each Participant’s immediate
supervisor, with input from team leaders, group and department heads and others,
as appropriate.

Program Bonus Targets

Under the Program, each Participant is eligible to earn a cash bonus in an
amount up to a specified percentage of his or her annual base salary that is
earned in 2009, with such percentage based [in part] upon the position such
Participant holds with the Company (the “Bonus Target”). Under the Program, the
Bonus Targets range from 25% to 40% of a Participant’s 2009 base salary for Vice
President level employees and above and from 6% to 20% of a Participant’s 2009
base salary for other Participants.

Determination of Cash Bonus Payments

The Company will determine the achievement of Corporate Objectives and
Individual Objectives shortly after the end of the Performance Period, as
follows:

Determination of Level of Achievement of Corporate Objectives

The Committee shall determine, after receiving and considering analysis and
recommendations from management, the degree to which the Corporate Objectives
have been met, expressed as a percentage of Corporate Objectives achieved,
taking into consideration the weighting assigned to each Corporate Objective.
Based on the percentage of Corporate Objectives achieved, the Committee will
then determine the final aggregate bonus pool under the Program for all
Participants (the “Bonus Pool”).

Adjustment of Bonus Targets based on Level of Achievement of Corporate
Objectives

Bonus Target levels for Participants will be adjusted based on level of
achievement of Corporate Objectives as determined by the Committee. For example,
if the Committee determines that only 80% of the Program’s Corporate Objectives
are achieved, each Participant’s Bonus Target will be decreased by 20% (in other
words, a Participant with a 10% Bonus Target will have that Bonus Target reduced
to 8%, or 80% of 10%.) Such adjusted Bonus Targets are referred to as the
“Adjusted Bonus Targets.”

Determination of Bonus Payments for Individual Participants

The actual Cash Bonus earned by a Participant is based on the Participant’s
(i) level of contribution to the achievement of the Corporate Objectives;
(ii) level of achievement by the Participant against his or her Individual
Objectives and (iii) Adjusted Bonus Target (or, if the Bonus Target was not
adjusted, the original Bonus Target). There is no set formula for determining
the amount of Cash Bonus earned based on the achievement of Individual
Objectives or Corporate Objectives. Rather, the Committee shall exercise its
discretion in determining the amount of Cash Bonus actually earned, which
determination will be final and binding. In making its determination, the
Committee shall consider the following:

 

  •  

For the Chief Executive Officer, the Committee’s own evaluation of his
achievements;

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  •  

For Executive Participants, the recommendations made by the Chief Executive
Officer; and

 

  •  

For Non-Executive Participants, the recommendations made by members of the
Executive Committee with input from team leaders, group and department heads and
supervisors, as appropriate.

In determining the actual Cash Bonus earned, the Committee may also take into
account the achievement of publicly announced targets, clinical milestones,
strategic goals, cross-functional teamwork and collaboration, and unforeseen
changes in the economy and/or geopolitical climate.

Timing of Cash Payments Under the Program

Payment of Cash Bonuses under the Program is expected to occur in the first
quarter following the conclusion of the Performance Period, on such date as
determined by the Committee in its sole discretion (the “Payment Date”). A
Participant must remain employed by the Company through the Payment Date in
order to earn any Cash Bonus. In no event will the Payment Date occur after
March 15, 2011, as the Program is intended to comply with Treasury Regulation
Section 1.409A-1(b)(4) and will be interpreted and administered in compliance
therewith to the greatest extent possible.

Miscellaneous Provisions

Participation in the Program shall not alter in any way the at will nature of
the Company’s employment of a Participant, and such employment may be terminated
at any time for any reason, with or without cause and with or without prior
notice. Nothing in this Program shall be construed to be a guarantee that any
Participant will receive all or part of a Cash Bonus or to imply a contract
between the Company and any Participant.

This Program supersedes and replaces all prior cash incentive and bonus plans of
the Company, other than the Change of Control Payment Plan and severance plans
(both Executive and Non-Executive). The Committee may amend or terminate this
Program at any time, with or without notice. The Committee may likewise
terminate an individual’s participation in the Program at any time, with or
without notice. Further, the Board of Directors or Committee may modify the
Corporate Objectives, the Individual Objectives, the Bonus Targets and/or the
weighting of the Corporate Objectives at any time.

The Program shall be interpreted in accordance with California law without
reference to conflicts of law principles.