Exhibit 10.501

CHIRON 2004 STOCK COMPENSATION PLAN  (As Amended and Restated February 13, 2004)

I.    PURPOSES

This Chiron 2004 Stock Compensation Plan, as amended and restated February 13, 2004, ("Plan"), formerly the Chiron 1991 Stock Option Plan, is intended to
enable Chiron Corporation ("Corporation") to attract and retain the following individuals by offering them incentives and rewards, in the form of options, stock issuances, restricted shares, share
rights, share units, stock appreciation rights (collectively, "awards") and purchase rights to purchase shares of the Corporation at periodic intervals through a purchase program, all of which will
encourage them to acquire a proprietary interest in the Corporation, to continue in the service of the Corporation or its subsidiaries, and to provide incentive to build value for stockholders:
(a) employees (including officers and directors) of the Corporation and its subsidiaries, (b) non-employee members of the Board of Directors of the Corporation ("Board"), and
(c) consultants and independent contractors who perform valuable services for the Corporation and its subsidiaries. This restatement of the Plan shall become effective upon receipt of
stockholder approval at the 2004 Annual Meeting, except as otherwise set forth herein.

II.    STRUCTURE OF THE PLAN

(a)   The
Plan shall be divided into three separate programs:



(b)   The
provisions of Sections IV and VIII shall apply only to the Discretionary Awards Program and the Automatic Awards Program. The provisions of Sections III, V, and X
shall apply to all programs under the Plan.

III.    ADMINISTRATION

The Plan will be administered by a committee or committees appointed by the Board and consisting of one or more members of the Board or a subcommittee or
subcommittees thereof. The Board may delegate the responsibility for administration of the Plan with respect to designated classes of award holders and different programs to different committees,
subject to such limitations as the Board deems appropriate, and each committee may similarly delegate its responsibilities to one or more subcommittees. Members of a committee or subcommittee will
serve for such term as the Board or committee may determine, and will be subject to removal by the Board at any time. The Board or a committee or subcommittee with authority to make awards hereunder
may delegate such authority to an officer of the Corporation to the extent permitted by Delaware corporate law. With respect to any matter, the term "Committee," when used in this Plan, will refer to
the committee or subcommittee or officer that has been delegated authority with respect to such matter.

In
determining the composition of any committee or subcommittee, the Board or committee, as the case may be, shall consider the desirability of compliance with the compositional
requirements of (i) Rule 16b-3 of the Securities and Exchange Commission with respect to award holders who are subject to the trading restrictions of Section 16(b) of
the Securities Exchange Act of 1934 ("1934 Act")

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with
respect to securities of the Corporation and (ii) Section 162(m) of the Code with respect to awards intended to qualify thereunder, but shall not be bound by such compliance.

Each
Committee will have full authority to administer the Plan within the scope of its delegated responsibilities, including authority to interpret and construe any relevant provision of
the Plan, to adopt such rules and regulations as it may deem necessary, and to determine the terms and conditions of awards made under the Plan (which need not be identical). With regard to the
Purchase Program, the Committee will have the full authority to interpret and construe any provision of the Purchase Program as it may deem necessary to comply with the requirements of
Section 423 of the Code. Decisions of a Committee made within the discretion delegated to it by the Board will be final and binding on all persons who have an interest in the Plan.

IV.    ELIGIBILITY FOR AWARDS

(a)   DISCRETIONARY
AWARDS PROGRAM. From time to time the Committee may, in its discretion, select individuals from among the following categories to receive awards under the
Plan:



(b)   AUTOMATIC
AWARDS PROGRAM. Members of the Board who are not employees of the Corporation or a subsidiary will receive awards in accordance with the Automatic Awards
Program under Section VII.

V. STOCK SUBJECT TO THE PLAN

(a)   CLASS.
The stock subject to awards under the Plan is (i) the Corporation's authorized but unissued or reacquired Common Stock ("Common Stock"), or
(ii) shares of one or more series of the Corporation's authorized but unissued or reacquired Restricted Common Stock, in the aggregate, "Company Stock." In connection with the grant of awards
under the Plan or issuance of shares under the Purchase Program, the Corporation may repurchase shares in the open market or otherwise.

(b)   AGGREGATE
AMOUNT



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(c)   ADJUSTMENTS.
In the event any change is made to the Company Stock subject to the Plan (whether by reason of merger, consolidation, reorganization, recapitalization,
stock dividend, stock split, combination of shares, exchange of shares, or other change in corporate or capital structure of the Corporation affecting the outstanding Common Stock as a class without
the Corporation's receipt of consideration) then, unless such change results in the termination of all awards, the Committee will make appropriate adjustments to (i) the number and/or class of
securities available under the Plan, (ii) the maximum number and/or class of securities by which the share reserve is to increase automatically each fiscal year pursuant to
Section V(b)(1), (iii) the number and/or class of securities for which any one person may be granted awards during the term of the Plan, (iv) the maximum number

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and/or
class of securities for which awards may be made to non-employee directors in any year, (v) the number and/or class of securities for which awards are to be made under
automatic grants to non-employee directors, (vi) the number and/or class of securities and, where applicable, price per share of securities subject to outstanding awards and
(vii) the number and class of securities available for issuance under the Purchase Program. Such adjustments are to be effected in a manner which shall preclude the enlargement or dilution of
rights and benefits of awards and shall be final, binding and conclusive.

VI.   TERMS AND CONDITIONS OF DISCRETIONARY AWARDS PROGRAM

(a)   NATURE
OF AWARDS



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(b)   WITHHOLDING.
The Committee may require, or permit an award holder to elect, that a portion of the total value of the shares of Company Stock otherwise payable under an
award be paid in the form of cash in lieu of the issuance of Company Stock and that such cash payment be applied to the satisfaction of the minimum income and employment tax withholding obligations
that are imposed under such award.

(c)   CASH
PAYMENTS. The Committee may provide award holders with an election to receive a percentage of the total value of the Company Stock subject to an award in the form
of a cash payment, subject to such terms, conditions and restrictions as the Committee shall specify.

(d)   ELECTIVE
AND TANDEM AWARDS. The Committee may award stock issuances, restricted shares, share rights, share units and stock appreciation rights independently of other
compensation or in lieu of compensation that would otherwise be paid in cash or another form of award, whether at the election of the potential award holder or otherwise. The number of shares,
restricted shares, share rights, share units or stock appreciation rights to be awarded in lieu of any cash compensation amount or other awards shall be determined by the Committee in its sole
discretion and need not be equal to such foregone compensation in Fair Market Value. In addition, restricted shares, share rights, share units and stock appreciation rights may be awarded in tandem
with stock options, so that a portion of such award becomes payable or becomes free of restrictions only if and to the extent that the tandem options are not exercised or are forfeited, subject to
such terms and conditions as the Committee may specify.

(e)   MODIFICATION
OF AWARDS. Subject to (f) below, the Committee may, in its sole discretion, modify or waive any or all of the terms, conditions or restrictions
applicable to any outstanding restricted share, share right, share unit or stock appreciation right; provided, however, that no such modification or waiver shall, without the consent of the holder of
an outstanding award, adversely affect the holder's rights thereunder.

(f)    SECTION
162(m). Stock options and stock appreciation rights granted with an exercise price equal to the Fair Market Value of the underlying shares are intended to
satisfy the performance-based compensation exemption from the limits of Section 162(m). The Committee may grant other awards that are intended to satisfy such exemption by basing the right to
payment thereunder or the vesting thereunder upon attainment of specified performance goals over a specified performance period, in accordance with the following provisions:



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VII. TERMS AND CONDITIONS OF AUTOMATIC AWARDS PROGRAM

In addition to the discretionary awards which may be granted to Board members as per Section IV(a)(3), the Board may also authorize automatic awards to be
made to non-employee members of the Board according to the following provisions of this Section VII. However, no individual non-employee Board member shall receive in
any one calendar year discretionary awards and automatic awards with respect to more than 25,000 shares of Common Stock, provided that the limit shall be 55,000 shares during his or her first calendar
year of Board service. Commencing June 30, 2003 and continuing until the Committee determines, in its sole discretion, to change the automatic grant program, the program shall be as described
below.

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(a)   OPTIONS. Non-employee members of the Board ("Eligible Directors") will automatically be granted nonstatutory options to purchase the number of shares of
Common Stock determined as set forth below (subject to adjustment under Section V(c) hereof) on the dates and terms set forth below:



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(b)   SHARE
RIGHTS. Eligible Directors will automatically be granted a number of share rights determined as set forth below (subject to adjustment under Section V(c)
hereof) on the dates and terms set forth below:



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Subject
to the limitations of Section X(b) and the annual limits specified above in this Section VII, the Board may change the automatic award program as it deems
appropriate. Additionally, the receipt of an automatic award, as specified in this Section VII, shall not preclude a non-employee member of the Board from receiving a discretionary
award.

VIII. OTHER TERMS AND CONDITIONS APPLICABLE TO DISCRETIONARY AWARDS PROGRAM AND AUTOMATIC AWARDS PROGRAM

(a)   ASSIGNABILITY.
No award granted under the Plan is assignable or transferable by the award holder other than by will or by the laws of descent and distribution, and
during the lifetime of the award holder, only the award holder may exercise options or exercise the rights provided under awards granted under the Plan. However, if and to the extent that the
Committee so authorizes at the time an award is granted or amended, an option (other than an option designated as an Incentive Option) or other award may be assigned in whole or in part during the
grantee's lifetime to one or more of the grantee's family members or an entity substantially owned, benefiting or controlled by the grantee or one or more of grantee's family members if and to the
extent that the Securities and Exchange Commission Form S-8 Registration Statement would continue to be available for the exercise of the award and resale of the underlying
securities following such assignment. The terms applicable to the assigned portion shall be the same as those in effect for the award immediately prior to such assignment and shall be set forth in
such documents issued to the assignee as the Committee may deem appropriate.

(b)   ACCELERATION
AND TERMINATION OF AWARDS



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(c)   VALUATION

With
regard to awards granted under this Plan, for all valuation purposes under the Plan, the Fair Market Value of a share of Common Stock or Restricted Common Stock (as the case may be)
on any relevant date will be determined in accordance with the following provisions:



(d)   REPURCHASE
RIGHTS

The
Committee may, in its discretion, establish as a term of one or more awards granted under the Plan that the Corporation (or its assigns) will have the right, exercisable upon the
award holder's termination of employment with, or cessation of services for, the Corporation and its subsidiaries, to repurchase at the original price paid, if any, for such shares of
(1) Company Stock acquired by the award holder pursuant to the granted award, or (2) Common Stock into which acquired Restricted Common Stock may have been converted or for which
Restricted Common Stock may have been exchanged. Any such repurchase right will be exercisable by the Corporation (or its assigns) upon such terms and conditions (including provisions for the
expiration of such right in one or more installments) as the Committee may specify in the instrument evidencing such right. The Committee will also have full power and authority to provide for the
automatic termination of the Corporation's repurchase rights, in whole or in part, thereby accelerating the vesting of any or all of the purchased shares (other than purchased shares obtained pursuant
to the Automatic Award provisions of this Plan) upon the occurrence of any change in control specified in Section VIII(b).

(e)   RIGHT
OF FIRST REFUSAL

The
Committee may, in its discretion, establish as a term of one or more awards granted under the Plan that the Corporation has a right of first refusal with respect to the proposed
disposition by the award holder (or any successor in interest by reason of purchase, gift or other mode of transfer) of any shares of (1) Company Stock acquired by the award holder pursuant to
the granted award, or (2) Common Stock into which purchased Restricted Common Stock may have been converted or for which acquired Restricted Common Stock may have been exchanged. Any such right
of first refusal will

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be
exercisable by the Corporation or its assigns in accordance with the terms and conditions specified in the instrument evidencing such right.

IX.   TERMS AND CONDITIONS OF THE PURCHASE PROGRAM

The Purchase Program is intended to allow eligible employees to purchase shares of Common Stock at periodic intervals, with their accumulated payroll deductions.

(a)   STOCK
SUBJECT TO PURCHASE PROGRAM. Subject to adjustment under Section V(c), the maximum number of shares of Common Stock which may be issued under the Purchase
Program is 6,400,000 shares.

(b)   ELIGIBILITY.
Unless otherwise specified by the Committee, each individual who is an employee of the Corporation (or parent or subsidiary, whether now existing or
subsequently established) is eligible to participate in the Purchase Program.

(c)   OFFERING
PERIODS. Shares of Common Stock will be offered under the Purchase Program in a series of successive offering periods, each with a maximum duration of
twenty-seven (27) months. Each offering period will be comprised of a series of one or more successive purchase intervals at the end of which shares will be purchased on behalf of each
participant.

(d)   PURCHASE
RIGHTS AND OTHER TERMS. The terms and conditions of the Purchase Program, including but not limited to the length of the offering periods and purchase
intervals, the terms of the purchase rights, the purchase price, the method of payment of the purchase price, limitations on payroll deductions and the number of shares purchasable during any purchase
interval or offering period and the rules and restrictions governing the Common Stock purchased pursuant to this program will be determined by the Committee in its sole discretion.

X. GENERAL PLAN PROVISIONS

(a)   EFFECTIVE
DATE AND TERM OF PLAN



(b)   AMENDMENT
OR DISCONTINUANCE



(c)   NO
OBLIGATION

Nothing
contained in the Plan (or in any award granted under this Plan) shall confer upon any employee, consultant, or independent contractor any right to continue in the employ of, or
to provide

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services
to, the Corporation or any affiliate or constitute a contract or agreement of employment or for the provision of services, or interfere in any way with the right of the Corporation or an
affiliate to reduce such employee's, consultant's or independent contractor's compensation from the rate in existence at the time of the granting of an award or to terminate such employee's,
consultant's or independent contractor's employment or services at any time, with or without cause; but nothing contained in the Plan or in any award granted under this Plan shall affect any
contractual rights of an employee pursuant to a written employment agreement.

(d)   USE
OF PROCEEDS

The
cash proceeds received by the Corporation pursuant to awards granted under the Plan will be used for general corporate purposes.

(e)   COMPLIANCE

No
option may be exercised, and the Corporation will not be obligated to issue stock under any award unless, in the opinion of counsel for the Corporation, such exercise and issuance is
in compliance with all applicable federal and state securities laws. As a condition to the grant of any award, or to the issuance of stock under any award, the Committee may require that the award
holder agree to comply with such provisions of federal and state securities laws as may be applicable to such grant, or to the
sale of stock acquired pursuant to the Plan, and that the award holder deliver to the Corporation a written agreement, in form and substance satisfactory to the Corporation and its counsel,
implementing such agreement.

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APPENDIX A  SPECIAL PROVISIONS RELATED TO 1995 CIBA-GEIGY TRANSACTION

Those persons holding options to acquire shares of Common Stock under the Corporation's Stock Option Plan (formerly the Corporation's "1991 Stock Option Plan") on
November 20, 1994 were granted the following rights ("Rights") with respect to each such option:



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