Exhibit 10.004

SECOND AMENDMENT

This SECOND AMENDMENT (this "Amendment") is made as of July 1, 2003 by and between BNP PARIBAS LEASING
CORPORATION, a Delaware corporation (as successor in interest to BNP Leasing Corporation) ("BNPLC"), and CHIRON CORPORATION, a Delaware corporation
("Chiron").

Recitals

A.    BNPLC
and Chiron executed, among other things, a Lease Agreement (as amended, the "Lease") a Purchase Agreement (as
amended, the "Purchase Agreement") dated as June 28, 1996 (but effective as of July 1, 1996), and a Ground Lease (as amended, the
"Ground Lease") dated as June 28, 1996 (but effective as of July 1, 1996), covering the Property located in Emeryville, Alameda County,
California.

B.    Chiron
has previously completed construction of the initial Construction Project described in Exhibit C of the Lease pursuant to the
terms of the Lease, and all Construction Advances have been previously made.

C.    Anticipating
Chiron's request for this amendment, BNP Paribas, San Francisco Branch, has on behalf of BNPLC requested the prior written approval of this Amendment by the
Participants.("Participants" and other capitalized terms defined in the Lease and used but not otherwise defined in this
Amendment are intended to have the meanings assigned to them in the Lease.)All Participants have given such approval, as evidenced by their execution of the consents below.

NOW,
THEREFORE, in consideration of the mutual covenants provided herein and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged,
BNPLC and Chiron agree as follows:



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[Signature pages follow.]

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IN
WITNESS WHEREOF, this Second Amendment has been executed as of July 1, 2003.

|  |  |                                                              |  |                
|- |  | ------------------------------------------------------------ |  | ---------------
|  |  | CHIRON CORPORATION                                          
|+ |  |                                                              |  |                
|  |  | By:                                                          |  | /s/JOEL R. JUNG
|  |  | Printed Name: Joel R. Jung
Title: Vice President & Treasurer

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[Continuation
of signature pages to Second Amendment dated to be effective as of July 1, 2003]

| |  |                                                         |  |                
| |  | ------------------------------------------------------- |  | ---------------
| |  | BNP PARIBAS LEASING CORPORATION,
a Delaware corporation
| |  | By:                                                     |  | /s/LLOYD G. COX
| |  | Printed Name: Lloyd G. Cox
Title: Managing Director    

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[Continuation
of signature pages to Second Amendment dated to be effective as of July 1, 2003]

The
undersigned Participant hereby consents to the foregoing Amendment.

| |  |                                                               |  |                          
| |  | ------------------------------------------------------------- |  | -------------------------
| |  | BNP PARIBAS                                                  
| |  | By:                                                           |  | /s/PIERRE NICHOLAS ROGERS
| |  | Printed Name: Pierre Nicholas Rogers
Title: Managing Director
| |  | By:                                                           |  | /s/RAFAEL C. LUMANIAN    
| |  | Printed Name: Rafael C. Lumanian
Title: Director             

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[Continuation
of signature pages to Second Amendment dated to be effective as of July 1, 2003]

The
undersigned Participant hereby consents to the foregoing Amendment.

| |  |                                                   |  |                  
| |  | ------------------------------------------------- |  | -----------------
| |  | CREDIT SUISSE FIRST BOSTON, CAYMAN ISLANDS BRANCH
| |  | By:                                               |  | /s/KARL M. STUDER
| |  | Printed Name: Karl M. Studer
Title: Director     
| |  | By:                                               |  | /s/BILL O'DALY   
| |  | Printed Name: Bill O'Daly
Title: Director        

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[Continuation
of signature pages to Second Amendment dated to be effective as of July 1, 2003]

The
undersigned Participant hereby consents to the foregoing Amendment.

| |  |                                                                                                    |  |                    
| |  | -------------------------------------------------------------------------------------------------- |  | -------------------
| |  | UBS AG, Cayman Islands Branch                                                                     
| |  | By:                                                                                                |  | /s/WILFRED V. SAINT
| |  | Printed Name: Wilfred V. Saint
Title: Associate Director
            Banking Products Services, US
| |  | By:                                                                                                |  | /s/PATRICIA O'KICKI
| |  | Printed Name: Patricia O'Kicki
Title: Director                                                    

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Exhibit A    Legal Description

REAL
PROPERTY IN CITY OF EMERYVILLE, COUNTY OF ALAMEDA, STATE OF CALIFORNIA DESCRIBED AS FOLLOWS:

LOT
ONE:

"ADJUSTED
LOT 1", AS DESCRIBED IN THE CERTIFICATE OF COMPLIANCE AND LOT LINE ADJUSTMENT RECORDED FEBRUARY 1, 2002, SERIES NO. 2002051905, OFFICIAL RECORDS, BEING ALL OF "RESULTING CHIRON LOT 1" AS
SAID LOT IS DESCRIBED IN THE LOT LINE ADJUSTMENT RECORDED NOVEMBER 13, 2001, SERIES NO. 2001441478, OFFICIAL RECORDS, AND A PORTION OF LOT 2 AS SHOWN ON THE PARCEL MAP ENTITLED, "PARCEL MAP NO. 7032,
CHIRON LIFE SCIENCES CENTER PHASE I", FILED SEPTEMBER 18, 1996 IN MAP BOOK 225, PAGES 35 THROUGH 37, ALAMEDA COUNTY RECORDS, MORE PARTICULARLY DESCRIBED AS FOLLOWS:

ALL
OF SAID "RESULTING CHIRON LOT 1" (2001441478);

AND
A PORTION OF SAID LOT 2 (225 PM 35) MORE PARTICULARLY DESCRIBED AS FOLLOWS:

BEGINNING
AT THE MOST WESTERN CORNER OF SAID LOT 2 (225 PM 35), THENCE ALONG THE BOUNDARY OF SAID LOT 2 THE FOLLOWING FOUR COURSES:

THENCE
LEAVING THE BOUNDARY OF SAID LOT 2, SOUTH 72°28'00" WEST 106.08 FEET; THENCE NORTH 17°32'00" WEST 22.00 FEET; THENCE SOUTH 72°28'00" WEST 203.60 FEET TO A
POINT ON THE BOUNDARY OF SAID LOT 2; THENCE ALONG THE BOUNDARY OF SAID LOT 2, NORTH 17°32'00" WEST 97.99 FEET TO THE POINT OF BEGINNING.

ASSESSOR'S
PARCEL NO. 049-1041-070-02

LOT
TWO:

"ADJUSTED
LOT 2", AS DESCRIBED IN THE CERTIFICATE OF COMPLIANCE AND LOT LINE ADJUSTMENT RECORDED FEBRUARY 1, 2002, SERIES NO. 2002051905, OFFICIAL RECORDS, BEING A PORTION OF LOT 2 AS SHOWN ON THE
PARCEL MAP ENTITLED, "PARCEL MAP NO. 7032, CHIRON LIFE SCIENCES CENTER PHASE I", FILED SEPTEMBER 18, 1996 IN MAP BOOK 225, PAGES 35 THROUGH 37, ALAMEDA COUNTY RECORDS, MORE PARTICULARLY DESCRIBED AS
FOLLOWS:

ALL
OF SAID LOT 2 (225 PM 35) EXCEPTING THEREFROM THE FOLLOWING DESCRIBED PARCEL:

BEGINNING
AT THE MOST WESTERN CORNER OF SAID LOT 2 (225 PM 35), THENCE ALONG THE BOUNDARY OF SAID LOT 2 THE FOLLOWING FOUR COURSES:

THENCE
LEAVING THE BOUNDARY OF SAID LOT 2, SOUTH 72°28'00" WEST 106.08 FEET; THENCE NORTH 17°32'00" WEST 22.00 FEET; THENCE SOUTH 72°28'00" WEST 203.60 FEET TO A
POINT ON THE BOUNDARY OF SAID LOT 2; THENCE ALONG THE BOUNDARY OF SAID LOT 2, NORTH 17°32'00" WEST 97.99 FEET TO THE POINT OF BEGINNING.

ASSESSOR'S
PARCEL NO. 049-1041-071-02

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Exhibit B

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Exhibit C    Form of Certificate

Chiron
Corporation
4560 Horton Street
Emeryville, California 94608-2916

Gentlemen:

This
Certificate is furnished pursuant to that certain Lease Agreement dated as of June 28, 1996 (as amended, the "Lease") and that
certain Second Amendment dated as of July 1, 2003 (the "Second Amendment"), the terms defined in the Lease and Second Amendment being used herein
as therein defined. The undersigned, as                        of BNP Paribas Leasing Corporation ("BNPLC"), does hereby certify
that the following are true, correct and complete in all material respects,
but only to the knowledge of BNPLC as of the date hereof:

Although
the representations required of BNPLC by this certificate are intended to coverfacts, it is understood and agreed (consistent
with subparagraph 7(f) of the Lease) that BNPLC has not made and will not make any representation or warranty as to the proper accounting by Chiron or its Affiliates of the Lease or as to other
accountingconclusions.

Executed
this            day of                        ,
20    .

| |  |                                 |  |        |  | 
| |  | ------------------------------- |  | ------ |  | 
| |  | BNP Paribas Leasing Corporation
| |  | By:                             |  |        |  | 
| |  |                                 |  |       
| |  |                                 |  | Name:  |  | 
| |  |                                 |  |        |  | 
| |  |                                 |  | Title: |  | 
| |  |                                 |  |        |  | 

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Exhibit JForm of Replacement Guaranty of Novartis, AG    GUARANTY

This
Guaranty is made effective as of July 1, 2003 by Novartis, AG (the "Guarantor") in favor of BNP Paribas Leasing Corporation, a
Delaware corporation, which is wholly owned by BNP Paribas ("BNPLC"), and in favor of BNP Paribas, Credit Suisse First Boston, UBS AG, Cayman Islands
Branch and any other banks or financial institutions that become "Participants" with BNPLC (as defined in the Lease). BNPLC and such Participants are sometimes hereinafter referred to collectively as
the "Banks".

WHEREAS,

At
the request of Chiron Corporation, a Delaware corporation ("Chiron"), in which the Guarantor is a major shareholder, BNPLC has advanced
funds to Chiron pursuant to the "Lease and Purchase Agreements" (as defined hereinafter), and BNPLC and the Participants have agreed to make certain modifications to the Lease and Purchase Agreements
pursuant to the Second Amendment of even date herewith (the "Amendment"), and

WHEREAS,

it
is a condition of BNPLC and the Participants to their execution of the Amendment, that the Guarantor guarantee the obligations of Chiron under the Lease and Purchase Agreements,

NOW,
THIS GUARANTY WITNESSES as follows:



The
Guarantor therefore undertakes to pay on first demand of BNPLC any amount payable under or as provided in the Lease and Purchase Agreements up to a maximum total amount (the
"Maximum Amount") of USD $173,330,000 irrespective of the validity and the legal effects of the Lease and Purchase Agreements, waiving all rights of
objection and defense arising therefrom upon receipt of the written request for payment and the statement in writing by BNPLC that Chiron has not made payment on the date(s) specified and the amount
called under the Guaranty.



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Except
as provided in the next paragraph, any demand for payment made by BNPLC upon Guarantor under this Guaranty will constitute a demand made not only for BNPLC itself, but also on
behalf of Participants. Further, if BNPLC does make such a demand for itself and for Participants, BNPLC shall distribute a portion of any payments BNPLC receives from Guarantor to Participants in
accordance with the Participation Agreements, and BNPLC shall also distribute a portion of any payments BNPLC receives from Guarantor to Participants in accordance with the Participation Agreements.



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| |  |              |  | 
| |  | ------------ |  | 
| |  | NOVARTIS, AG
| |  | By:          |  | 
| |  |              |  | 

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