Exhibit 10.42

AMENDMENT NO. 1 CO-PROMOTION AGREEMENT

CV THERAPEUTICS, INC.

AND

SOLVAY PHARMACEUTICALS, INC.

This Amendment No. 1 to CO-PROMOTION AGREEMENT (hereinafter “Amendment”) is made
on the 6th day of March, 2006, between Solvay Pharmaceuticals, Inc., a
corporation organized and existing under the laws of the State of Georgia and
having a principal place of business at 901 Sawyer Road, Marietta Georgia 30062,
U.S.A. (hereinafter “Solvay”) and CV THERAPEUTICS, INC., a corporation organized
and existing under the laws of the State of Delaware and having a principal
place of business at 3172 Porter Drive, Palo Alto, California 94304, U.S.A.
(hereinafter “CV Therapeutics”).

WHEREAS, CV Therapeutics and Solvay entered into an CO-PROMOTION AGREEMENT
effective on December 6,2004 (hereinafter “Agreement”); and

WHEREAS, CV Therapeutics and Solvay desire to amend that Agreement as set forth
in this Amendment.

NOW, THEREFORE, CV Therapeutics and Solvay, in consideration of their mutual
promises, understand and agree as follows:

 

  1. Section 4.1(a)(iii) of the Agreement is hereby amended in its entirety to
read as follows:

“(iii) The Baseline will be prorated for any partial calendar quarter occurring
during the Term. The initial value of the Baseline will be [*] per calendar
quarter, provided that starting with the calendar quarter in which the EUROPA
sNDA FDA Approval is obtained, for the remainder of [*] of the Term the Baseline
shall be changed to [*] per calendar quarter. For [*], the Baseline will be [*]
for the first calendar quarter of [*], [*] for the second calendar quarter of
[*], and [*] for the third and fourth calendar quarters of [*]. Thereafter
during the Term, the Baseline for every remaining calendar quarter shall be [*],
as may be adjusted from time to time during the Term in accordance with the
other provisions of Section 4.1 of this Agreement; provided, however, the
Baseline will not be adjusted in any manner for any price changes for the
Product during the Term.”

 

  2. Section 4.l(a)(iv) of the Agreement is hereby deleted in its entirety and
is of no force and effect during the Term.

 

  3. Except as amended by this Amendment, all other terms and conditions of the
Agreement remain in full force and effect. In the event of any conflict between
the terms and conditions of the Agreement and the terms and conditions of this
Amendment, the terms and conditions of this Amendment shall govern.

 

  * Confidential treatment has been requested for portions of this exhibit. The
copy filed herewith omits the information subject to the confidentiality
request. Omissions are designated as [*]. A complete version of this exhibit has
been filed separately with the Securities and Exchange Commission.

 

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IN WITNESS WHEREOF, CV THERAPEUTICS, INC. and SOLVAY PHARMACEUTICALS, INC.,
intending to be legally bound have caused this Amendment to be executed by their
duly authorized representatives and affirm the commitment to adhere strictly to
the Agreement as amended by this Amendment.

 

CV THERAPEUTICS, INC.

 

SOLVAY PHARMACEUTICALS, INC.

By:

 

/s/ Louis G. Lange

 

By:

 

/s/ L.J. Downey

Print Name:

 

Louis G. Lange, M.D., Ph.D.

 

Print Name:

 

L.J. Downey, M.D.

Title:

 

Chairman & CEO

 

Title:

 

President & CEO

Date:

 

March 2, 2006

 

Date:

 

March 6, 2006

 

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