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                                                                   EXHIBIT 10.50
                                  CONFIDENTIAL


March 31, 1999




Ms. Sandra Woodruff
Executive Director
Veterans Medical Research Foundation
VA Medical Center (151A)
3350 La Jolla Village Drive
San Diego,  CA  92161

Dear Sandra:

Collateral Therapeutics, Inc. (hereinafter "CTI") proposes that this letter be
the written agreement which sets forth the understanding and obligations of the
parties regarding the research conducted by Dr. Kirk Hammond in the field of
cardiovascular disease (hereinafter, the "Studies").

1.       Kirk Hammond, M.D. (hereinafter "Investigator") and the Veterans
         Medical Research Foundation (hereinafter "VMRF" or the "Foundation")
         agree to utilize their best efforts to conduct the Studies. Further
         details concerning the Studies will be discussed in confidence by the
         Investigator with CTI representatives. If during the term of this
         agreement, the Investigator shall cease to conduct the studies,
         and/or no longer be employed by the Veterns' Affairs Healthcare
         System, then VMRF shall promptly so notify CTI and CTI shall have
         the option to terminate the funding of the studies.  CTI will
         promptly advise VMRF in writing if CTI so elects.

2.       The Investigator agrees to comply with the federal regulations relating
         to the Animal Welfare Act (7. U.S.C. 2131, et seq) and the United
         States Department of Agriculture regulations as set forth in 9 C.F.R.
         parts 1, 2, and 3.

3.       The Investigator will render periodic confidential reports as may be
         requested to CTI.

4.       In preparation for and during the course of these Studies, it may be
         necessary for CTI to disclose to the Investigator or to VMRF certain
         technical and business information; all such information, as well as
         the results of the research, subject to the restriction in paragraph #5
         of this agreement, is considered to be highly confidential by CTI. It
         is understood that VMRF may disclose the amount of this research
         funding in any routine disclosure as required by VMRF policy, but shall
         not use or disclose the subject matter of the research. The
         Investigator and the Foundation agree to take all reasonable
         precautions to prevent disclosure of this and other


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Veterans Medical Research Foundation
March 19, 1999
Page 2


         confidential information to others and to not use confidential
         information without the prior express written consent of CTI. These
         restrictions upon disclosure of said information shall extend beyond
         the term of this contract for a period of ten (10) years, but shall
         cease to apply as to any specific portion of the information which is
         or becomes available to the public other than by the Investigator or
         the Foundation's fault.

5.       The text of any oral or written disclosure of the results of the
         Studies shall be submitted to CTI at least sixty (60) days prior to any
         and all such disclosures. The Investigator and the Foundation shall
         consider any suggestions from CTI concerning said disclosure, but are
         not bound to incorporate such suggestions in any oral or written
         publications. CTI may request addition of a sponsor's representative to
         authorship on documents submitted for publication. The Investigator and
         the Foundation agree to delay any such disclosure for up to six (6)
         months following notification of CTI, at CTI's request, to allow for
         completion of development and filing of patent applications.

6.       The Investigator and VMRF agree to disclose promptly and fully to an
         authorized representative of CTI all ideas, developments and
         inventions, whether or not patentable, conceived or reduced to practice
         by the Investigator and/or VMRF as a result of the Studies provided for
         herein. All of such ideas, developments and inventions shall be the
         property of CTI. Accordingly, the Investigator and VMRF agree to assign
         outright to CTI the entire right, title and interest, both in the
         United States and abroad, to such ideas, developments and inventions
         and any resulting patent applications and patents, without payment
         other than the fees provided for herein. The Investigator and VMRF
         further agree to execute any and all documents and take such other
         steps which CTI determines are necessary or convenient to fully
         implement its proprietary rights in such ideas, developments and
         inventions, such as, including but not limited to executing assignment
         documents, filing and obtaining patents, and fully cooperating in the
         prosecution of such property rights, but at no expense to them. CTI
         will have the above-mentioned patent documents drafted, prosecuted and
         maintained at its own expense. The Investigator and VMRF warrant that
         it has appropriate ownership rights in such ideas, developments and
         inventions to carry out its obligations under this paragraph. Both
         parties acknowledge that in so far as U.S. government facilities or
         resources are utilized in this work, the U.S. Government may have
         rights in any invention and may choose to exercise these rights.

7.       Both parties also acknowledge that the Department of Veterans Affairs
         has informed the VMRF that VMRF has waived all patent rights that may
         develop in connection with this agreement.


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Veterans Medical Research Foundation
March 19, 1999
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8.       CTI shall have the right to use the results and data of the Studies in
         any manner deemed appropriate to CTI's business interests. Such uses
         may include but are not limited to, disclosure as may be useful to meet
         legal and business obligations, such as to support patent applications,
         both foreign and domestic, or satisfy the requirements of any
         government agency. In the event that work resulting from the Studies is
         published in the scientific literature by CTI, acknowledgement will be
         made to the Investigator and the Department of Veterans Affairs in the
         accepted style, as appropriate. CTI will not use the name of the
         Investigator or VMRF for advertising, other commercial purposes, in
         publications or otherwise without appropriate written permission,
         unless required by law or government regulations. CTI agrees that the
         investigator shall have priority publication rights over data generated
         from these studies subject to paragraph #5.

9.       In consideration for the Studies, during the term of this agreement CTI
         agrees to pay VMRF direct reimbursement for all expenditures made by
         VMRF in connection with the Studies as directed by the Investigator,
         and pay reimbursement for certain direct costs based on the formula as
         set forth below. In this regard, CTI agrees to pay VMRF the following:
         (i) a $5,000 primary monthly payment (hereafter the "Primary Monthly
         Payment"); (ii) a supplemental monthly payment (hereafter the
         "Supplemental Monthly Payment") equal to all other expenditures made by
         VMRF in connection with the Studies during each month of the term of
         this agreement in excess of the Primary Monthly Payment; and (iii) a
         monthly payment covering the allocable indirect costs associated with
         all amounts expended by VMRF for the Studies which shall be computed by
         multiplying the sum of the Primary Monthly Payment and the Supplemental
         Payment by a 40% indirect overhead factor.

         The amount of the Supplemental Monthly Payment will be computed based
         on the overall level of expenditures by VMRF for the Studies each
         month, less the Primary Monthly Payment. VMRF shall agree to provide
         CTI with sufficient information for it to compute the Supplemental
         Monthly Payment. Following the term of the agreement, VMRF shall agree
         to promptly return any amounts advanced to VMRF by CTI for which there
         is not any corresponding expenditure in connection with the Studies.

         CTI shall have the right to review any and all financial records of
         VMRF relating solely to these Studies on a quarterly basis, to
         determine the sufficiency of the Supplemental Payment. Annually VMRF
         shall provide CTI with a financial statement and account reconciliation
         covering all amounts expended by VMRF for the Studies during the term
         of this agreement.


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Veterans Medical Research Foundation
March 19, 1999
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10.      This contract will become effective on March 31, 1999, and will
         terminate three years from that date unless otherwise extended by
         mutual consent of CTI and the Foundation and Investigator, evidenced
         by written agreement.

11.      The parties agree to take all other action necessary to effect the
         rights of the parties herein.

12.      Only VMRF or CTI, or an assignee or affiliate of VMRF or CTI, shall
         have rights to enforce any obligation under this Agreement. No other
         persons or entities shall be deemed an intended beneficiary under this
         Agreement.

13.      The parties acknowledge that Dr. Robert L. Engler may have a conflict
         of interest regarding this agreement and Dr. J. Parthemore shall serve
         in his place for VMRF on all matters relating to this agreement.

14.      If any provision of this Agreement is held to be unenforceable for any
         reason, it shall be adjusted if possible rather than voided in order to
         achieve the intent of the parties to the greatest extent possible. In
         any event, other provisions of the Agreement shall be deemed valid and
         enforceable to the greatest extent possible.

If the terms of this agreement meet with the approval of the Veterans Medical
Research Foundation, please sign and date two copies and return one to CTI at
your earliest convenience.

Most Sincerely,
COLLATERAL THERAPEUTICS, INC.

/s/ Christopher J. Reinhard
-------------------------------
Christopher J. Reinhard
Chief Financial and Operating Officer


ACCEPTED AND AGREED TO:
VETERANS MEDICAL RESEARCH FOUNDATION

/s/ Sandra Woodruff                          4/12/99
--------------------------------             ---------------------------------
Sandra Woodruff                              Date

PRINCIPLE INVESTIGATOR

/s/ Dr. H. Kirk Hammond                       4/15/99
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Dr. H. Kirk Hammond                          Date