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Confidential treatment has been requested for portions of this document. 
Brackets indicate portions of text that have been omitted. A separate filing 
of such omitted text has been made with the Commission as part of the 
Company's application for confidential treatment.

                                                                Exhibit 10.43


                           [CV THERAPEUTICS LETTERHEAD]


March 7, 1997

Dr. Ron Kudla
Director of Technology and Licensing
University of Florida
182 Grinter Hall
Gainesville, Florida 32611-2037

RE:  AMENDMENT OF LICENSE AGREEMENT

Dear Ron:

As you know, CVT has been involved in extensive negotiations with a 
pharmaceutical company (the "Pharma") regarding a collaboration agreement 
(the "Collaboration") under which, among other things, CVT would license 
Pharma the rights to complete development of and commercially market CVT-124 
(or any related adenosine A, antagonist), which is covered by the terms of 
the License Agreement between CVT and UFRFI dated June 27, 1994 (the "License 
Agreement"). We are pleased to inform UFRFI that CVT and Pharma are extremely 
close to completing the Collaboration negotiations and entering into the 
agreement, which we believe is a very significant step towards the successful 
commercialization of CVT-124.

As is typical of such transactions, Pharma has certain accounting and 
patented-related policies that are required provisions in its collaboration, 
some of which are inconsistent with the terms of the License Agreement.  To 
enter into the Collaboration, thus, Pharma has insisted on resolution of 
these inconsistencies between the License Agreement and the terms of the 
Collaboration agreement, and on obtaining confirmation from UFRFI regarding 
certain terms.  We agree that it is in the interest of all parties to do so. 
We proposed that the most efficient way to achieve this is to amend the terms 
of the License Agreement, so that such terms are inconsistent with the terms 
that Pharma is insisting be present in the Collaboration agreement, and to 
provide the needed confirmation.

If it is agreeable with UFRFI, this letter agreement will serve to amend the 
terms of the License Agreement as set forth below, and to provide certain 
confirmation from UFRFI regarding the License Agreement and the sublicenses 
granted by CVT to Pharma under the Collaboration.  We will forward to you on 
Friday applicable portions of the latest draft of the Collaboration agreement 
(redacted for confidentiality), for your review in conjunction with the 
modifications and confirmations set forth below.

1.   The parties agree to modify Section 1.6 of the License Agreement regarding
     the definition of "Licensed Product", to read in its entirety as follows:
     
     "1.6   A `Licensed Product' shall mean any product or part thereof which:
          
            (a)  is covered by a Valid Claim in the Patent Rights in the 
                 country in which such product or part thereof is made, used 
                 or sold; or
<PAGE>

            (b)  is manufactured using a process which is covered in whole or 
                 in part by a Valid Claim contained in the Patent Rights in the 
                 country in which such process is used; or
            
            (c)  includes any of the Know-How not otherwise includable in the 
                 Patent Rights."
            
2.   The parties agree to modify Section 1.7 of the License Agreement regarding
     the definition of "Net Sales", to read in its entirety as follows:
     
     "1.7   `Net Sales' shall mean Licensee's billings and its sublicensees'
            receipts (except as provided below) for Licensed Products sold
            hereunder less the sum of the following:
          
            (a)  trade, quantity, cash or other discounts and brokers' or 
                 agents' commissions, if any, allowed in amounts not 
                 exceeding amounts customary in the trade, including, without 
                 limitation, governmental program discounts and rebates 
                 (e.g., Medicaid, Medicare, VA, etc.);
            
            (b)  sales taxes, tariff duties and/or use taxes directly imposed 
                 on and with reference to particular sales;
            
            (c)  packing, transportation and insurance prepaid or allowed; and
            
            (d)  amounts allowed or credited on rejects, returns or 
                 retroactive price reductions.

     If Licensee receives royalties from any sublicensee on the basis of such
     sublicensee's billings for Licensed Products, it shall pay royalties to
     UFRFI on the basis of such sublicensee's billings.  A sale or transfer of
     a Licensed Product by Licensee or is sublicensee to an affiliate for re-
     sale of the Licensed Product by such affiliate shall not be considered a
     sale for the purpose of this provision, but the resale of the Licensed
     Product by such affiliate to a third party shall be a sale for such
     purposes.
     
     In the event that a Licensed Product is sold in the form of a combination
     product containing an active ingredient that meets the definition of
     "Licensed Product" above and one or more other active ingredients, Net
     Sales shall be determined by multiplying Net Sales of the combination
     product (as defined above) by the fraction A/A+B where A is the fair
     market value of the active ingredient that meets the definition of
     "Licensed Product" and B is the sum of the fair market values of all 
     other active ingredients included in the combination product.  If either 
     A or B or both are sole independently of the combination product as a 
     stand-alone product, the `fair market value' for purposes hereof will be 
     the gross sales price of such independent sale."
     
3.   The parties agree to add a new Section 1.14 to the License Agreement to
     define the term Valid Claim, as follows:


                                      2.
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     "1.14  `Valid Claim' shall mean (i) a claim of a pending patent
            application which claim shall not have been canceled, withdrawn 
            or rejected by an administrative agency from which no appeal can 
            be taken and which application shall not have been pending for 
            more than four (4) years, or (ii) a claim in an issued and 
            unexpired patent which has not lapsed or become abandoned or 
            been declared invalid or unenforceable by a court of competent 
            jurisdiction or an administrative agency from which no appeal 
            can be or is taken."
          
4.   UFRFI hereby confirms that the [ * ] has no right, title or interest in, 
     or any license rights under, the Patent Rights, as defined in the 
     License Agreement.
     
5.   UFRFI hereby confirms that, with respect to the Collaboration agreement to
     be entered into with Pharma, CVT has satisfied the requirements of Section
     2.6 and the second sentence of Section 2.7 of the License Agreement by
     providing Pharma a copy of the License Agreement.
     
6.   UFRFI confirms that CVT may satisfy the requirements of Section 3.2(a) of
     the License Agreement, with respect to the activities of Pharma as CVT's
     sublicensee, by delivery to URFRI of an annual report from Pharma
     summarizing Pharma's planned development activities for the coming year
     and results with respect to CVT-124 during the prior year.
     
7.   UFRFI agrees that Section 3.2(b) of the License Agreement shall not apply
     to any sublicensees of CVT.
     
8.   UFRFI hereby confirms that [ * ] consistent with Section 6.1 of the
     License Agreement, permit [ * ] to undertake, on [ * ] under the 
     License Agreement, responsible for [ * ] with respect to the Patent 
     Rights.
     
9.   The parties hereby agree to modify Section 6.5 of the License Agreement to
     read in its entirety as follows:
     
     "6.5   For so long as [ * ] under this Agreement, [ * ] shall have the 
            first right and opportunity, solely at its expense, for defending 
            and enforcing the Patent Rights.  However, [ * ] shall receive 
            notice of and shall have the right, at its expense, to participate 
            in the protection and defense of the Patent Rights, and [ * ] 
            agrees to be joined as a party plaintiff in any such suit if 
            necessary or appropriate.  [ * ] agrees to cooperate reasonably 
            in any such litigation initiated by [ * ] including participating 
            as a necessary party, supplying essential documentary evidence and 
            making essential witnesses in [ * ] employment available.  [ * ]
            shall have the right to settle and compromise any dispute with 
            third parties, with the prior written consent of [ * ] which 


* Confidential Treatment Requested.

                                      3.
<PAGE>

            consent shall not be unreasonably withheld.  All costs, fees and 
            expenses incurred by [ * ] in connection with the defense and 
            enforcement of the Patent Rights shall be borne by [ * ] provided, 
            however, that [ * ] and [ * ] in connection therewith.  Said [ * ] 
            shall begin no earlier than the [ * ].  Any [ * ] pursuant to this 
            Article VI.  The balance remaining from any such recovery shall be 
            deemed to [ * ].  To the extent that [ * ] shall be entitled to 
            [ * ] under this Agreement.
          
10.  The parties hereby agree to modify Section 6.6 of the License Agreement
     to read in its entirety as follows:
     
     "6.6   If [ * ] elects not to take action to address such third party 
            infringement, then [ * ] may, if it so desires, request that 
            [ * ] to do so.  If [ * ] consents in writing, then [ * ] may 
            take such legally permissible action as it deems necessary or 
            appropriate to enforce the Patent Rights and restrain such 
            infringement.  In such event, all costs, fees and expenses 
            incurred in connection with the defense and enforcement of the 
            Patent Rights shall be borne by [ * ] agrees to cooperate 
            reasonably in any such litigation initiated by [ * ] as permitted 
            hereunder, including participating as a necessary party, supplying 
            essential documentary evidence and making essential witnesses in 
            [ * ] employment available.  If [ * ] shall prevail in such 
            proceeding, either by way of judgment or settlement or compromise, 
            any amounts recovered by [ * ] shall be retained by [ * ].
          
11.  UFRFI hereby confirms that CVT may disclose to Pharma in confidence under
     the terms of the Collaboration the Know-How and other Confidential
     Information of UFRFI disclosed to CVT pursuant to the License Agreement,
     without violating the provisions of the Article VIII of the License
     Agreement.
     
A full copy of the collaboration agreement will be forwarded to you on the date
of signing.  Within ten (10) days thereafter, CV Therapeutics will provide a
full accounting of UFRFI, including payment to UFRFI under the terms of the
License Agreement.


* Confidential Treatment Requested.


                                      4.
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If you agree with the provisions of this letter agreement, please indicate 
your agreement by signing the enclosed copy of this letter agreement on the 
line below, telecopy a copy to me at CV Therapeutics and return the signed 
copy to me in the enclosed envelope.  We look forward to proceeding to enter 
the Collaboration and to the successful commercialization of CVT-124 in 
collaboration with Pharma.


Yours sincerely,

CV THERAPEUTICS, INC.

/s/ MICHAEL J. STERNS, D.V.M.

Michael J. Sterns, D.V.M.
Director, Business Development





ACCEPTED AND AGREED:

THE UNIVERSITY OF FLORIDA RESEARCH FOUNDATION, INC.



By:  /s/ RONALD M. KUDLA
   ----------------------------------------
     Dr. Ron Kudla, Ph.D., duly authorized

Date:  March 7, 1997
     --------------------------------------


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