Exhibit 99.4
JOINT FILING AGREEMENT
In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934,
as amended, the undersigned hereby agree that this Statement on Schedule 13D
with respect to the beneficial ownership of shares of Common Stock of Chiron
Corporation is filed jointly, on behalf of each of them. This Agreement may be
executed in any number of counterparts, all of which taken together shall
constitute one and the same instrument.
Dated: April 3, 2006
NOVARTIS BIOTECH PARTNERSHIP,
INC.
By: /s/ Xxxxx X. Xxxxxxxxx
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Name: Xxxxx X. Xxxxxxxxx
Title: Vice President
NOVARTIS CORPORATION
By: /s/ Xxxxxx Xxxxxx
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Name: Xxxxxx Xxxxxx
Title: General Counsel
NOVARTIS PHARMA AG
By: /s/ Xxxxxx Xxxxxx
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Name: Xxxxxx Xxxxxx
Title: Group General Counsel
By: /s/ Xxx Xxxxxxxxxx
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Name: Xxx Xxxxxxxxxx
Title: Head Legal and General Affairs
NOVARTIS AG
By: /s/ Xxxxx Xxxxxx
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Name: Xxxxx Xxxxxx
Title: Corporate Secretary
By: /s/ Xxx Xxxxxxxxxx
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Name: Xxx Xxxxxxxxxx
Title: Head Legal and General Affairs