Document:

<PAGE>
                                                                   EXHIBIT 10.30

                              [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED
                                  IN THIS DOCUMENT, MARKED BY BRACKETS, HAS BEEN
                                OMITTED AND FILED SEPARATELY WITH THE SECURITIES
                                  AND EXCHANGE COMMISSION PURSUANT TO RULE 24B-2
                             OF THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED.

           AMENDMENT NO. 3 TO PATENT AND TECHNOLOGY LICENSE AGREEMENT

This Amendment No. 3 to Patent and Technology License Agreement (THIRD
AMENDMENT) is made and entered into as of November 6, 2003 by and between
Myogen, Inc. (LICENSEE) and the Board of Regents (BOARD) of the University of
Texas System (SYSTEM).

                                    RECITALS

A. LICENSEE and BOARD entered into a Patent and Technology License Agreement
effective as of December 1, 1999, and amended as of July 7, 2000 and December
20, 2001 (LICENSE AGREEMENT).

B. LICENSEE and BOARD wish to further amend the terms of the LICENSE AGREEMENT
as set forth below.

NOW, THEREFORE, it is hereby agreed as follows:

1. Section 4.5 of the LICENSE AGREEMENT shall be revised to read in its entirety
as follows:

         "4.5 For the period commencing with the EFFECTIVE DATE and continuing
through the [/\#/\] BOARD grants LICENSEE an exclusive option (OPTION) to
negotiate an exclusive, royalty-bearing, worldwide license for inventions,
discoveries and intellectual properties related to LICENSED SUBJECT MATTER that
were developed by INVENTOR at UT SOUTHWESTERN and: (i) which result from
research conducted under funding sources other than the SPONSORED RESEARCH
AGREEMENT; and (ii) which are not otherwise obligated to any other third party;
and (iii) which are not for use within GENE THERAPY. This exclusive right to
negotiate a license will extend for 12 months (OPTION PERIOD) commencing with
receipt by LICENSEE of a written description of the invention from UT
SOUTHWESTERN. During the OPTION PERIOD, LICENSEE will pay all patent expenses
incurred by UT SOUTHWESTERN for inventions, discoveries and intellectual
properties included under the OPTION not to exceed [/\#/\]. LICENSEE may
exercise its option at any time during the OPTION PERIOD by notifying BOARD and
UT SOUTHWESTERN in writing of its intent to exercise this option. If LICENSEE
exercises its OPTION, BOARD and UT SOUTHWESTERN agree to diligently negotiate
with LICENSEE for an exclusive, royalty-bearing, worldwide license. Such license
will provide for a license fee of [/\#/\], an annual license reissue fee of
[/\#/\], a royalty rate as specified in Section 5.1(d), and other reasonable and
customary terms as the parties may agree upon. In the event that the parties are
unable to successfully negotiate an exclusive license agreement within 90 days
after LICENSEE exercises its OPTION, either party may supply the other with
written notice of its intent to terminate license negotiations. If license
negotiations are terminated, LICENSEE will, for an additional 3 month period
retain the right to obtain an exclusive, worldwide, royalty-bearing license for
such invention for the same consideration set forth in any new proposed license
agreement that UT SOUTHWESTERN might negotiate with any other party, provided
that the consideration to be provided as part of the new proposed license
agreement between UT SOUTHWESTERN and such third party is less than the
consideration offered by LICENSEE in its last proposal before termination of
license negotiations. Upon UT SOUTHWESTERN'S written notification to LICENSEE of
any such new proposal, LICENSEE shall have 10 days to notify UT SOUTHWESTERN of
its election."

                                         [/\#/\]CONFIDENTIAL TREATMENT REQUESTED

                                  Page 1 of 3
<PAGE>

2. Section 5.1(c) of the LICENSE AGREEMENT shall be revised to read in its
entirety as follows:

         " "(c) Milestone payments according to the schedule shown below are due
         within 30 days of the initiation of each milestone event in the
         development of any LICENSED PRODUCT or IDENTIFIED PRODUCT, regardless
         of whether the milestone event is performed by LICENSEE, AFFILIATE,
         NON-SUBLICENSEE CORPORATE PARTNER, or sublicensee. Once a milestone
         payment has been made for a particular milestone event shown below, no
         further payments shall be due upon any subsequent occurrence of such
         milestone event. The amounts of the milestone payments are as follows:

         Initiation of Phase One clinical trials          [/\#/\]
         Initiation of Phase Two clinical trials          [/\#/\]
         Initiation of Phase Three clinical trials        [/\#/\]
         NDA approval in the U.S. for a LICENSED
         PRODUCT or IDENTIFIED PRODUCT                    [/\#/\]

         For the purpose of this Section 5.1(c), "Initiation" shall mean receipt
         by the first patient of the first dose of a LICENSED PRODUCT or
         IDENTIFIED PRODUCT;"

3. Section 5.1(d) of the LICENSE AGREEMENT shall be revised to read in its
entirety as follows:

                  "(d) A running earned royalty equal to [/\#/\] of NET SALES of
         any and all LICENSED PRODUCTS and/or IDENTIFIED PRODUCTS; provided,
         however, that if the total earned royalty due to LICENSEE by a
         NON-SUBLICENSEE CORPORATE PARTNER or sublicensee with respect to a
         LICENSED PRODUCT and/or IDENTIFIED PRODUCT is reduced upon the
         expiration of applicable PATENT RIGHTS or introduction of a generic
         product, the earned royalty due to BOARD by LICENSEE will be
         proportionately reduced, on a product-by-product basis, but in no event
         shall the earned royalty owed by LICENSEE in such instance be greater
         than [/\#/\] of the total earned royalty due to LICENSEE from a
         NON-SUBLICENSEE CORPORATE PARTNER or sublicensee."

4. Section 5.1(f) of the LICENSE AGREEMENT shall be revised to read in its
entirety as follows:

                  "(f) [/\#/\] of any and all revenues from either SUBLICENSE
         REVENUES or NON-SUBLICENSEE CORPORATE PARTNERSHIP REVENUES, whichever
         applies; provided, however, if LICENSEE receives SUBLICENSE REVENUES in
         consideration for the grant of a sublicense under the licenses granted
         to LICENSEE hereunder and such sublicense also includes the grant of a
         license or sublicense to other technology controlled by LICENSEE but
         not acquired from BOARD, then the foregoing amount shall be adjusted by
         a percentage that fairly represents, as reasonably determined by the
         parties, the contribution of the relevant LICENSED SUBJECT MATTER to
         the total revenue received by LICENSEE.

5. Except as expressly provided in this THIRD AMENDMENT, all other terms,
conditions and provisions of the LICENSE AGREEMENT shall continue in full force
and effect as provided therein.

                           ((Signature Page Follows))

                                         [/\#/\]CONFIDENTIAL TREATMENT REQUESTED

                                  Page 2 of 3

<PAGE>

IN WITNESS WHEREOF, LICENSEE and BOARD have entered into this THIRD AMENDMENT
effective as of the date first set forth above.

BOARD OF REGENTS OF THE                           MYOGEN, INC.
UNIVERSITY OF TEXAS SYSTEM

By       /s/ John A. Roan                         By /s/ J. William Freytag
  ---------------------------------------------     ----------------------------
  John A. Roan                                      J. William Freytag
  Executive Vice President for Business Affairs     President and CEO
  UT Southwestern Medical Center at Dallas

Date   12/1/03                                    Date   11-14-03
       -------                                           --------

Approved as to Content:

By  /s/ Dennis K. Stone
  ---------------------------------------------
  Dennis K. Stone, M.D.
  Vice President for Technology Development
  UT Southwestern Medical Center at Dallas

Date   11/26/03
       --------

                                         [/\#/\]CONFIDENTIAL TREATMENT REQUESTED

                                  Page 3 of 3<PAGE>
                                                                   EXHIBIT 10.31

                              [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED
                                  IN THIS DOCUMENT, MARKED BY BRACKETS, HAS BEEN
                                OMITTED AND FILED SEPARATELY WITH THE SECURITIES
                                  AND EXCHANGE COMMISSION PURSUANT TO RULE 24B-2
                             OF THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED.

           AMENDMENT NO. 1 TO PATENT AND TECHNOLOGY LICENSE AGREEMENT

         This Amendment No. 1 to Patent and Technology License Agreement (FIRST
AMENDMENT) is made and entered into as of February 10, 2004 by and between
Myogen, Inc. (LICENSEE) and the Board of Regents (BOARD) of the University of
Texas System (SYSTEM).

                                    RECITALS

A. LICENSEE and BOARD entered into a Patent and Technology License Agreement
effective as of January 1, 2002 (LICENSE AGREEMENT).

B. LICENSEE and BOARD wish to further amend the terms of the LICENSE AGREEMENT
as set forth below.

NOW, THEREFORE, it is hereby agreed as follows:

1. Section 5.1c of the LICENSE AGREEMENT shall be revised to read in its
entirety as follows:

         "milestone fees according to the table below, due and payable within 30
days of each milestone event for the first LICENSED PRODUCT or IDENTIFIED
PRODUCT to achieve such milestone event, [/\#/\], provided however, if LICENSEE
pays a milestone fee under the 1999 AGREEMENT for a milestone event listed
below, such payment is creditable toward the milestone fee due for the same
milestone event for the same LICENSED PRODUCT or IDENTIFIED PRODUCT pursuant to
this Section 5.1c:

<Table>
<Caption>
      MILESTONE EVENT                                        MILESTONE FEE
      ------------------------------------------------       -------------------
<S>                                                          <C>
      The date the first patient is dosed in the first       [/\#/\]
      Phase III clinical trial

      NDA approval in the U.S. for a LICENSED                [/\#/\]
      PRODUCT or IDENTIFIED PRODUCT
</Table>

2. Section 5.1d of the LICENSE AGREEMENT shall be revised to read in its
entirety as follows:

         "a running royalty equal to [/\#/\] of NET SALES [/\#/\], subject to
adjustment under Sections 5.1e and 5.1f below; provided, however, that if the
total earned royalty due to LICENSEE by a NON-SUBLICENSEE CORPORATE PARTNER or
sublicensee with respect to a LICENSED PRODUCT and/or IDENTIFIED PRODUCT is
reduced upon the expiration of applicable PATENT RIGHTS or introduction of a
generic product, the earned royalty due to BOARD by LICENSEE will be [/\#/\],
but in no event shall the earned royalty owed by LICENSEE in such instance be
greater than [/\#/\] of the total earned royalty due to LICENSEE from a
NON-SUBLICENSEE CORPORATE PARTNER or sublicensee;"

3. Section 5.1h of the LICENSE AGREEMENT shall be revised to read in its
entirety as follows:

         "a sublicense fee of [/\#/\] of SUBLICENSEE REVENUES and/or
NON-SUBLICENSEE CORPORATE PARTNERSHIP REVENUES, subject to adjustment under
Section 5.1i below, payable within 30 days of LICENSEE'S receipt of any such
consideration; provided, however, if LICENSEE receives SUBLICENSE REVENUES in
consideration for the grant of a sublicense under the licenses granted to
LICENSEE hereunder

                                        [/\#/\] CONFIDENTIAL TREATMENT REQUESTED

                                   Page 1 of 2
<PAGE>

and such sublicense also includes the grant of a license or sublicense to other
technology controlled by LICENSEE but not acquired from BOARD, then the
foregoing amount shall be adjusted by a percentage that fairly represents, as
reasonably determined by the parties, the contribution of the relevant LICENSED
SUBJECT MATTER to the total revenue received by LICENSEE; and"

4. Except as expressly provided in this FIRST AMENDMENT, all other terms,
conditions and provisions of the LICENSE AGREEMENT shall continue in full force
and effect as provided therein.

         IN WITNESS WHEREOF, LICENSEE and BOARD have entered into this FIRST
AMENDMENT effective as of the date first set forth above.

BOARD OF REGENTS OF THE                            MYOGEN, INC.
UNIVERSITY OF TEXAS SYSTEM

By    /s/ John A. Roan                             By    /s/ J. William Freytag
  ---------------------------------------------      ---------------------------
  John A. Roan                                       J. William Freytag
  Executive Vice President for Business Affairs      President and CEO
  UT Southwestern Medical Center at Dallas

Date 2/25/04                                       Date 2/10/04
     -------                                            -------

Approved as to Content:

By    /s/ Dennis K. Stone
  -----------------------------------------
  Dennis K. Stone, M.D.
  Vice President for Technology Development
  UT Southwestern Medical Center at Dallas

Date 2/25/04

                                        [/\#/\] CONFIDENTIAL TREATMENT REQUESTED

                                   Page 2 of 2

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