Document:

<PAGE>
                                                                   EXHIBIT 10.22

                                [*#*] 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 406
                                      OF THE SECURITIES ACT OF 1933, AS AMENDED.

                         EXCLUSIVE PATENT AND TECHNOLOGY

                                LICENSE AGREEMENT

                                     BETWEEN

                         THE UNIVERSITY OF TEXAS SYSTEM

                                       AND

                                  MYOGEN, INC.

<PAGE>

                                TABLE OF CONTENTS

<Table>
<S>                                                                             <C>
         RECITALS                                                               PAGE 1

1.       EFFECTIVE DATE                                                         PAGE 1

2.       DEFINITIONS                                                            PAGE 1

3.       WARRANTY, SUPERIOR RIGHTS                                              PAGE 3

4.       LICENSE                                                                PAGE 4

5.       PAYMENTS AND REPORTS                                                   PAGE 5

6.       SPONSORED RESEARCH                                                     PAGE 7

7.       TERM AND TERMINATION                                                   PAGE 7

8.       INFRINGEMENT BY THIRD PARTIES                                          PAGE 8

9.       ASSIGNMENT                                                             PAGE 8

10.      PATENT MARKING                                                         PAGE 9

11.      INDEMNIFICATION                                                        PAGE 9

12.      USE OF NAME                                                            PAGE 9

13.      CONFIDENTIAL INFORMATION                                               PAGE 9

14.      PATENTS AND INVENTIONS                                                 PAGE 10

15.      GENERAL                                                                PAGE 11

         SIGNATURES                                                             PAGE 13
</Table>

                                         *#*   CONFIDENTIAL TREATMENT REQUESTED

<PAGE>

                EXCLUSIVE PATENT AND TECHNOLOGY LICENSE AGREEMENT
                     BETWEEN THE UNIVERSITY OF TEXAS SYSTEM
                                       AND
                                  MYOGEN, INC.

THIS Agreement (AGREEMENT) is between the Board of Regents (BOARD) of The
University of Texas System (SYSTEM), an agency of the State of Texas, whose
address is 201 West 7th Street, Austin, Texas 78701, on behalf of the University
of Texas Southwestern Medical Center at Dallas (UT SOUTHWESTERN), a component
institution of SYSTEM, and Myogen, Inc. (LICENSEE), a Delaware corporation
having a principal place of business located at 7577 West 103rd Avenue, Suite
212, Westminster, Colorado 80021-5426.

                                    RECITALS

A. BOARD owns certain PATENT RIGHTS (as defined below) and TECHNOLOGY RIGHTS (as
defined below) related to LICENSED SUBJECT MATTER (as defined below), which were
developed at UT SOUTHWESTERN.

B. BOARD desires to have the LICENSED SUBJECT MATTER developed and used for the
benefit of LICENSEE, INVENTOR (as defined below), BOARD, and the public as
outlined in BOARD'S Intellectual Property Policy.

C. BOARD and LICENSEE entered into a Patent and Technology License Agreement
effective December 1, 1999 (1999 AGREEMENT) for a related technology.

D. LICENSEE wishes to obtain a license from BOARD to practice LICENSED SUBJECT
MATTER.

E. LICENSEE intends to sponsor research relating to LICENSED SUBJECT MATTER at
UT SOUTHWESTERN to further develop LICENSED SUBJECT MATTER and to identify
related technologies and the parties will execute a sponsored research agreement
(SPONSORED RESEARCH AGREEMENT) in the form attached hereto as Exhibit 2
concurrently with the execution of this AGREEMENT.

NOW, THEREFORE, in consideration of the mutual covenants and premises herein
contained, the parties agree as follows:

                                1. EFFECTIVE DATE

This AGREEMENT is effective January 1, 2002 (EFFECTIVE DATE).

                                 2. DEFINITIONS

As used in this AGREEMENT, the following terms have the meanings indicated:

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2.1 AFFILIATE means any business entity 50% or more owned by LICENSEE, any
business entity which owns 50% or more of LICENSEE, or any business entity that
is 50% or more owned by a business entity that owns 50% or more of LICENSEE.

2.2 IDENTIFIED PRODUCT means any product, or derivative thereof, which product
or derivative is not covered by PATENT RIGHTS but either (a) elicits a positive
response in technologies covered by PATENT RIGHTS, or (b) was identified,
selected, or found to be useful, in whole or in part, through the use of one or
more technologies (including, but not limited to assays, methods, and/or
reagents) covered by PATENT RIGHTS. For greater certainty, the parties
acknowledge and agree that IDENTIFIED PRODUCTS are not LICENSED PRODUCTS (as
defined below).

2.3 INVENTOR(S) means [*#*].

2.4 LICENSED FIELD means: (i) treatment, prevention, diagnosis and/or prognosis
of cardiac hypertrophy, heart disease and heart failure; and (ii) determination
of predisposition to cardiac hypertrophy, heart disease and heart failure.

2.5 LICENSED PRODUCT means any compound, assay, method, reagent, technology,
product or service comprising LICENSED SUBJECT MATTER pursuant to this
AGREEMENT.

2.6 LICENSED SUBJECT MATTER means inventions, discoveries, assays and processes
covered by PATENT RIGHTS and/or TECHNOLOGY RIGHTS within LICENSED FIELD.

2.7 NET SALES means [*#*].

2.8 NON-SUBLICENSEE CORPORATE PARTNER means any third party with which LICENSEE
has entered into an agreement either to determine the feasibility of developing
and commercializing LICENSED PRODUCTS and/or IDENTIFIED PRODUCTS with such third
party, or to develop and/or commercialize LICENSED PRODUCTS and/or IDENTIFIED
PRODUCTS with such third party, and where such third party in not a sublicensee
as set forth in Section 4.4 under the terms of this AGREEMENT.

2.9 NON-SUBLICENSEE CORPORATE PARTNERSHIP REVENUES means [*#*].

2.10 PATENT RIGHTS means BOARD'S rights in information or discoveries covered by
a VALID CLAIM (as defined below) in patents, and/or patent applications, whether
domestic or foreign, and all divisionals, continuations, continuations-in-part,
reissues, reexaminations or extensions thereof, and any letters patent that
issue thereon, as: (i) set forth in Exhibit 1 attached hereto; or (ii)
discovered, conceived and/or reduced to practice during the term of and directly
resulting from the research performed under the SPONSORED RESEARCH AGREEMENT.

2.11 SALE, SELL OR SOLD means [*#*].

2.12 SUBLICENSEE REVENUES means [*#*].

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2.13 TECHNOLOGY RIGHTS means BOARD'S rights in technical information, know-how,
processes, procedures, compositions, devices, methods, formulas, protocols,
techniques, software, designs, drawings or data created by INVENTOR(S) at UT
SOUTHWESTERN before or during the term of the SPONSORED RESEARCH AGREEMENT
relating to the LICENSED SUBJECT MATTER that are not covered by PATENT RIGHTS
but that are necessary or useful for practicing the invention(s) covered by
PATENT RIGHTS and are not obligated to any other third party.

2.14 THIRD PARTY means any person or entity other than LICENSEE, its AFFILIATES,
NON-SUBLICENSEE CORPORATE PARTNERS or sublicensees.

2.15 VALID CLAIM means a claim or claims of. (i) an issued, unexpired patent,
whether domestic or foreign, so long as any such claim shall not have been held
invalid or unenforceable in an unappealed or an unappealable decision, in a
court of competent jurisdiction; or (ii) a pending patent application, whether
foreign or domestic, so long as any such claim shall not have been pending for
more than 5 years.

                          3. WARRANTY: SUPERIOR-RIGHTS

3.1 Except for the rights, if any, of the government of the United States of
America (GOVERNMENT), as set forth below, BOARD represents and warrants (1) that
it is the owner of the entire right, title, and interest in and to LICENSED
SUBJECT MATTER, (2) that it has the sole right to grant licenses thereunder, and
(3) that to the best of its knowledge it has not knowingly granted licenses
thereunder to any other entity that would restrict rights granted to LICENSEE
except as stated herein.

3.2 LICENSEE understands that the LICENSED SUBJECT MATTER may have been
developed under a funding agreement with the GOVERNMENT and, if so, that the
GOVERNMENT may have certain rights relative thereto. This AGREEMENT is
explicitly made subject to the GOVERNMENT's rights under any agreement and any
applicable law or regulation. If there is a conflict between any agreement,
applicable law or regulation and this AGREEMENT, the terms of the GOVERNMENT
agreement, applicable law or regulation shall prevail.

3.3 LICENSEE understands and acknowledges that BOARD, by this AGREEMENT, makes
no representation as to the operability or fitness for any use, safety,
efficacy, approvability by regulatory authorities, time and cost of development,
patentability, and/or breadth of the LICENSED SUBJECT MATTER. BOARD, by this
AGREEMENT, also makes no representation as to whether there are any patents now
held, or which will be held, by others or by BOARD which may be dominant or
subordinate to PATENT RIGHTS, nor does BOARD make any representation that the
inventions contained in PATENT RIGHTS do not infringe any other patents now held
or that will be held by others or by BOARD.

3.4 LICENSEE, by execution hereof, acknowledges, covenants and agrees that it
has not been induced in anyway by BOARD, SYSTEM, UT SOUTHWESTERN or its
employees to enter into this AGREEMENT, and further warrants and represents that
(1) it has had sufficient

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opportunity to conduct due diligence with respect to all items and issues
pertaining to the LICENSED SUBJECT MATTER; and (2) LICENSEE has adequate
knowledge and expertise, or has utilized knowledgeable and expert consultants,
to adequately conduct the due diligence.

                                   4. LICENSE

4.1 BOARD hereby grants to LICENSEE a royalty-bearing, worldwide, exclusive
license under LICENSED SUBJECT MATTER to discover, research, develop, make, have
made, use offer for SALE, SELL and import LICENSED PRODUCTS and IDENTIFIED
PRODUCTS for use within LICENSED FIELD. This grant is subject to the payment by
LICENSEE to BOARD of all consideration as provided herein, and is further
subject to rights retained by BOARD to:

         a. publish the general scientific findings from research related to
         LICENSED SUBJECT MATTER and IDENTIFIED PRODUCTS subject to the terms of
         Article 13, Confidential Information, provided however, INVENTOR shall
         disclose pending publications to LICENSEE in accordance with Section
         6.1 of the SPONSORED RESEARCH AGREEMENT; and

         b. use LICENSED SUBJECT MATTER and IDENTIFIED PRODUCTS for research
         that has not been sponsored by a commercial entity, teaching and other
         educationally-related purposes, provided, however, that any such use
         with respect to IDENTIFIED PRODUCTS shall be limited to IDENTIFIED
         PRODUCTS which are either (1) owned by BOARD, or (2) provided to BOARD
         by an authorized party. Any transfer of material embodiments of
         LICENSED SUBJECT MATTER pursuant to this Section 4.1b shall be governed
         by a material transfer agreement substantially in the form attached
         hereto as Exhibit 3.

4.2 [*#*]

4.3 LICENSEE may extend the license granted herein to any AFFILIATE if the
AFFILIATE consents in writing to be bound by this AGREEMENT to the same extent
as LICENSEE. LICENSEE must deliver to BOARD a true and accurate copy of such
written agreement, and any modification or termination thereof, within 30 days
after execution, modification or termination.

4.4 LICENSEE may grant sublicenses consistent with this AGREEMENT if LICENSEE is
responsible for the operations of its sublicensees relevant to this AGREEMENT as
if the operations were carried out by LICENSEE, [*#*]. LICENSEE must deliver to
BOARD a true and correct copy of each sublicense granted by LICENSEE, and any
modification or termination thereof, within 30 days after execution,
modification, or termination. When this AGREEMENT is terminated, BOARD and UT
SOUTHWESTERN agree to accept as successors to LICENSEE existing sublicensees in
good standing at the date of termination, provided that the sublicensees consent
in writing to be bound by all the terms and conditions of this AGREEMENT.

4.5 LICENSEE may enter into agreements with NON-SUBLICENSEE CORPORATE PARTNERS
consistent with this AGREEMENT if LICENSEE is responsible for the operations of
its NON-SUBLICENSEE CORPORATE PARTNERS relevant to this AGREEMENT as if

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the operations were carried out by LICENSEE [*#*]. LICENSEE must deliver to
BOARD a true and correct copy of each NON-SUBLICENSEE CORPORATE PARTNER
agreement granted by LICENSEE, and any modification or termination thereof,
within 30 days after execution, modification, or termination thereof (which copy
may be redacted to delete information not relevant to determining whether
LICENSEE and/or NON-SUBLICENSEE CORPORATE PARTNER have complied with their
obligations to BOARD hereunder). [*#*]

                             5. PAYMENTS AND REPORTS

5.1 In consideration of rights granted by BOARD to LICENSEE under this
AGREEMENT, LICENSEE will pay BOARD the following:

         a. [*#*] license documentation fee in the amount of [*#*], due and
         payable within 30 days of LICENSEE'S receipt of a fully executed
         AGREEMENT from BOARD;

         b. an annual license reissue fee in the amount of [*#*], due and
         payable within 30 days of each anniversary of the EFFECTIVE DATE
         beginning on [*#*];

         c. 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
         Filing of the first new drug application                 [*#*]
</Table>

         d. a running royalty equal to [*#*] of NET SALES [*#*], subject to
         adjustment under Sections 5.1e and 5.1f below;

         e. if LICENSEE is required to pay royalties to a third party under
         patents owned by such third party to use, manufacture, have
         manufactured, offer for SALE, SELL or import LICENSED PRODUCTS or
         IDENTIFIED PRODUCTS, then LICENSEE may reduce the royalty payment owed
         to BOARD on the same LICENSED PRODUCT or IDENTIFIED PRODUCT under
         Section 5.1d by an amount equal to [*#*], but in no event shall such
         reduction result in a royalty of less than [*#*] of the royalties due
         pursuant to Section 5.1d;

         f. if LICENSEE is required to pay royalties on a LICENSED PRODUCT or
         IDENTIFIED PRODUCT under the 1999 AGREEMENT then LICENSEE may reduce
         the royalty payment owed to BOARD on the same LICENSED PRODUCT or
         IDENTIFIED PRODUCT under Section 5.1d by an amount equal to [*#*];

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         g. [*#*] for all out-of-pocket expenses paid by UT SOUTHWESTERN prior
         to [*#*] in filing, prosecuting, enforcing and maintaining PATENT
         RIGHTS, and all such expenses paid by UT SOUTHWESTERN on or after
         [*#*]. UT SOUTHWESTERN will invoice LICENSEE within 60 days of the
         EFFECTIVE DATE and on a quarterly basis thereafter. The invoiced
         amounts will be due and payable by LICENSEE within 30 days;

         h. 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; and

         i. if LICENSEE is required to pay a fee pursuant to Section 5.1(f) of
         the 1999 AGREEMENT, then LICENSEE may reduce the sublicensee fee owed
         to BOARD on the same SUBLICENSEE REVENUES or the same NON-SUBLICENSEE
         CORPORATE PARTNERSHIP REVENUES under Section 5.1h above by an amount
         [*#*].

5.2 During the term of this AGREEMENT and for 1 year thereafter, LICENSEE agrees
to keep sufficiently complete and accurate records of its and its sublicensees'
SALES and NET SALES under the license granted in this AGREEMENT to enable the
royalties payable hereunder to be determined. LICENSEE agrees to permit BOARD or
its representatives, at BOARD'S expense and with 14 days written notice, to
periodically examine such records during regular business hours for the purpose
of and to the extent necessary to verify any report required under this
AGREEMENT, provided that such examination occurs not more frequently than 2
times per year. [*#*]

5.3 Within 30 days after March 31, June 30, September 30, and December 31 of
each year of the valid term of this AGREEMENT, beginning after the first to
occur of: (i) LICENSEE'S receipt of SUBLICENSEE REVENUES; (ii) LICENSEE'S
receipt of NON-SUBLICENSEE CORPORATE PARTNERSHIP REVENUES; or (iii) first SALE
of a LICENSED PRODUCT or IDENTIFIED PRODUCT, LICENSEE must deliver to BOARD a
true and accurate written report, even if no payments are due BOARD, giving the
particulars of the business conducted by LICENSEE and its sublicensee(s) and
NON-SUBLICENSEE CORPORATE PARTNERS, if any exist, during the preceding 3
calendar months under this AGREEMENT as are pertinent to calculating payments
hereunder. This report will include at least:

         [*#*]

Simultaneously with the delivery of each report, LICENSEE must pay to BOARD the
amount, if any, due for the period of each report. Such reports and records are
to be treated as LICENSEE'S Confidential Information and therefore subject to
the obligations set forth in Article 13.

5.4 On or before each anniversary of the EFFECTIVE DATE, irrespective of having
a first SALE or offer for SALE, LICENSEE must deliver to BOARD a written
progress report as to LICENSEE'S (and any sublicensee's) efforts and
accomplishments during the preceding year in commercializing LICENSED SUBJECT
MATTER and LICENSEE'S (and sublicensee's and

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NON-SUBLICENSEE CORPORATE PARTNER'S) commercialization plans for the upcoming
year.

5.5 [*#*] Check must be payable to UT SOUTHWESTERN and sent to:

         UT Southwestern Medical Center at Dallas
         Office for Technology Development
         5323 Harry Hines Boulevard
         Dallas, Texas 75390-9094
         ATTN: Director for Technology Development

                              6. SPONSORED RESEARCH

LICENSEE and UT SOUTHWESTERN have entered into, concurrently with this
AGREEMENT, a SPONSORED RESEARCH AGREEMENT in the form attached hereto as Exhibit
2.

                             7. TERM AND TERMINATION

7.1 The term of this AGREEMENT is from the EFFECTIVE DATE and continues on a
country-by-country and product-by-product basis for:

         a. LICENSED PRODUCTS to the full end of the term or terms for which
         PATENT RIGHTS have not expired; and

         b. IDENTIFIED PRODUCTS until [*#*].

7.2 Any time after [*#*] from the, EFFECTIVE DATE, BOARD and UT SOUTHWESTERN
have the right to terminate this license in any national political jurisdiction
if LICENSEE, within 90 days after receiving written notice from UT SOUTHWESTERN
of the intended termination, fails to provide written evidence satisfactory to
UT SOUTHWESTERN that LICENSEE or its sublicensee(s) has commercialized or is
actively attempting to commercialize a licensed invention in such
jurisdiction(s). The following definitions apply to Article 7: (1)
"commercialize" means [*#*]; (2) "attempting to commercialize" means [*#*]. Such
commercialization plans are to be treated as LICENSEE'S Confidential Information
and therefore subject to the obligations set forth in Article 13.

7.3 This AGREEMENT will earlier terminate:

         a. automatically if LICENSEE becomes bankrupt or insolvent and/or if
         the business of LICENSEE is placed in the hands of a receiver,
         assignee, or trustee, whether by voluntary act of LICENSEE or
         otherwise; or

         b. upon 60 days written notice from BOARD if LICENSEE breaches or
         defaults on its obligation to make payments (if any are due) or
         reports, in accordance with the terms

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         of Article 5 hereunder, unless, before the end of the 60 day period,
         LICENSEE has cured the breach or default and so notifies BOARD, stating
         the manner of the cure; or

         c. upon 90 days written notice if LICENSEE breaches or defaults on any
         other obligation under this AGREEMENT, unless, before the end of the 90
         day period, LICENSEE has cured the breach or default and so notifies
         BOARD, stating the manner of the cure; or

         d. at any time by mutual written agreement between LICENSEE, UT
         SOUTHWESTERN and BOARD, upon 30 days written notice to all parties and
         subject to any terms herein which survive termination; or

         e. under the provisions of Section 7.2 if invoked.

7.4 If this AGREEMENT is terminated for any cause:

         a. nothing herein will be construed to release either party of any
         obligation matured prior to the effective date of the termination;

         b. after the effective date of the termination, LICENSEE will provide
         BOARD with a written inventory of all LICENSED PRODUCTS and/or
         IDENTIFIED PRODUCTS in process of manufacture, in use or in stock.
         LICENSEE may SELL any such LICENSED PRODUCTS and/or IDENTIFIED PRODUCTS
         [*#*]

         c. LICENSEE will be bound by the provisions of Articles 11
         (Indemnification), 12 (Use of Name), and 13 (Confidential Information)
         of this AGREEMENT.

                        8. INFRINGEMENT BY THIRD PARTIES

8.1 LICENSEE, [*#*] must enforce any patent exclusively licensed hereunder
against infringement by third parties and it is entitled to retain recovery from
such enforcement. [*#*] If LICENSEE does not file suit against a substantial
infringer of a patent within [*#*] of knowledge thereof, then BOARD may enforce
any patent licensed hereunder on behalf of itself and LICENSEE, [*#*]. LICENSEE
and BOARD shall each provide the other prompt written notice of alleged
infringement by any third party of the PATENT RIGHTS.

8.2 In any infringement suit or dispute, the parties agree to cooperate fully
with each other. At the request and expense of the party bringing suit, the
other party will permit access to all relevant personnel, records, papers,
information, samples, specimens, etc., during regular business hours.

                                  9. ASSIGNMENT

Except in connection with the sale of substantially all of LICENSEE'S assets or
outstanding capital stock (including by merger, reorganization or
recapitalization) to a third party, this

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AGREEMENT may not be assigned by LICENSEE without the prior written consent of
BOARD, which will not be unreasonably withheld.

                               10. PATENT MARKING

LICENSEE must permanently and legibly mark all products, packaging and
documentation manufactured or SOLD by it under this AGREEMENT with a patent
notice as may be permitted or required under Title 35, United States Code.

                               11. INDEMNIFICATION

LICENSEE agrees to hold harmless and indemnify BOARD, INVENTOR, SYSTEM, UT
SOUTHWESTERN, its Regents, officers, employees and agents from and against any
claims, demands, or causes of action whatsoever, including without limitation
those arising on account of any injury or death of persons or damage to property
caused by, or arising out of, or resulting from, the exercise or practice of the
license granted hereunder by LICENSEE, its AFFILIATES or their officers,
employees, agents or representatives.

                                 12. USE OF NAME

LICENSEE may not use the name of UT SOUTHWESTERN, SYSTEM, INVENTOR(S) or BOARD
without express written consent from UT SOUTHWESTERN and/or SYSTEM, except as
required by law, rule or regulation.

                          13. CONFIDENTIAL INFORMATION

13.1 BOARD and LICENSEE each agree that the terms and conditions contained in
this AGREEMENT and all information contained in documents marked "confidential"
and forwarded to one by the other for the purposes of this AGREEMENT
("Confidential Information") are: (1) to be received in strict confidence, (2)
to be used only for the purposes of this AGREEMENT, and (3) not to be disclosed
by the recipient party, its agents or employees without the prior written
consent of the other party, except to the extent that the recipient party can
establish competent written proof that such information:

         a. was in the public domain at the time of disclosure;

         b. later became part of the public domain through no act or omission of
         the recipient party, its employees, agents, successors or assigns;

         c. was lawfully disclosed to the recipient party by a third party
         having the right to disclose it;

         d. was already known by the recipient party at the time of disclosure;

         e. was independently developed by the recipient; or

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         f. is required by law or regulation to be disclosed, provided however,
         that the disclosing party shall first give the other party written
         notice and adequate opportunity to object to such order for disclosure
         or to request confidential treatment.

13.2 Information shall not be deemed to be available to the public or to be in
the recipient's possession merely because it:

         a. includes information that falls within an area of general knowledge
         available to the public or to the recipient (i.e., it does not include
         the specific information provided by the other party); or

         b. can be reconstructed in hindsight from a combination of information
         from multiple sources that are available to the public or to the
         recipient, unless one of those sources actually teaches or suggests the
         entire combination, together with its meaning and importance.

13.3 Each party may disclose the other's Confidential Information to the extent
such disclosure is reasonably necessary in filing or prosecuting patent
applications, prosecuting or defending litigation, complying with applicable
governmental regulations or conducting pre-clinical or clinical trials, provided
that if a party is required by law or regulation to make any disclosure of the
other party's Confidential Information it will, except where impracticable for
necessary disclosures, give reasonable advance notice to the other party of such
disclosure, requirement and, except to the extent inappropriate in the case of
patent applications, will use reasonable diligent efforts to secure confidential
treatment of such Confidential Information required to be disclosed. In
addition, LICENSEE may disclose the terms and conditions of this AGREEMENT to
its potential and current investors or to any entity that may potentially
acquire rights or licenses from LICENSEE provided such party agrees to the
confidentiality provisions in this Article 13.

13.4 Each party's obligation of confidence hereunder shall be fulfilled by using
at least the same degree of care with the other party's confidential information
as it uses to protect its own confidential information. This obligation shall
exist while this AGREEMENT is in force and for a period of 3 years thereafter.

                           14. PATENTS AND INVENTIONS

14.1 BOARD and UT SOUTHWESTERN will select the patent attorney, patent agent
and/or law firm responsible for searching, filing, prosecuting and maintaining
patent applications and patents for LICENSED SUBJECT MATTER, such attorney,
agent and/or law firm to be reasonably acceptable to LICENSEE.

14.2 If after consultation, both parties agree that a patent application should
be filed for LICENSED SUBJECT MATTER, BOARD will authorize the preparation and
filing of the appropriate patent applications and such applications will be
included under PATENT RIGHTS (the parties agree to timely amend Exhibit 1 in
writing when new matter is added under

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PATENT RIGHTS). If LICENSEE does not respond or make an effort to agree with
BOARD on the disposition of rights in the subject invention, then BOARD may file
an application [*#*].

14.3 [*#*]

14.4 LICENSEE will arrange to provide UT SOUTHWESTERN a copy of all patent
applications filed for LICENSED SUBJECT MATTER [*#*] as well as copies of any
patent related communications, including, but not limited to, office actions,
responses and invoices. The parties each have the right to review and comment
upon the wording of specifications, claims and responses to office actions prior
to their submission to the appropriate patent office.

                                   15. GENERAL

15.1 This AGREEMENT constitutes the entire and only agreement between the
parties for LICENSED SUBJECT MATTER and all other prior negotiations,
representations, agreements, and understandings are superseded hereby. No
agreements altering or supplementing the terms hereof may be made except by a
written document signed by both parties.

15.2 Any notice required by this AGREEMENT must be given by facsimile
transmission confirmed by personal delivery (including delivery by reputable
messenger services such as Federal Express) or by prepaid, first class,
certified mail, return receipt requested, addressed in the case of BOARD and UT
SOUTHWESTERN to:

         UT Southwestern
         Ray Wheatley
         Director, Technology Development
         5323 Harry Hines Boulevard
         Dallas, Texas 75390-9094
         Phone: (214) 648-1888
         Fax: (214) 648-1889

     With copies to:

         Board of Regents
         The University of Texas System
         201 West 7th Street
         Austin, Texas 78701
         ATTENTION: Office of General Counsel
         Phone: (512) 499-4462
         Fax: (512) 499-4523

or in the case of LICENSEE to:

         J. William Freytag
         CEO and President
         Myogen, Inc.
         7577 W. 103rd Avenue
         Westminster, CO 80021-5426
         Phone: (303) 410-6666
         Fax: (303) 410-6667

or other addresses as may be given from time to time under the terms of this
notice provision.

                                 Page 11 of 15

                                         *#*   CONFIDENTIAL TREATMENT REQUESTED

<PAGE>

15.3 Each party must comply with all applicable national, state and local laws
and regulations in connection with its activities pursuant to this AGREEMENT.

15.4 This AGREEMENT will be construed and enforced in accordance with the laws
of the United States of America and of the State of Texas.

15.5 Failure of either party to enforce a right under this AGREEMENT will not
act as a waiver of that right or the ability to later assert that right relative
to the particular situation involved.

15.6 Headings are included herein for convenience only and shall not be used to
construe this AGREEMENT.

15.7 If any part of this AGREEMENT is for any reason found to be unenforceable,
all other parts nevertheless remain enforceable.

15.8 Neither party shall be held liable or responsible to the other party nor be
deemed to have defaulted under or breached this AGREEMENT for failure or delay
in fulfilling or performing any term of this AGREEMENT when such failure or
delay is caused by or results from causes beyond the reasonable control of the
affected party, including, without limitation, fire, floods, earthquakes,
natural disasters, embargoes, war, acts of war (whether war be declared or not),
insurrections, riots, civil commotions, strikes, lockouts or other labor
disturbances, acts of God or acts, omissions or delays in acting by any
governmental authority or the other party.

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<PAGE>

IN WITNESS WHEREOF, parties hereto have caused their duly authorized
representatives to. execute this AGREEMENT.

<Table>
<S>                                                  <C>
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        CEO and President
   UT Southwestern Medical Center at Dallas

Date  12/27/01                                       Date  12/31/01
     ----------                                           ----------
</Table>

Approved as to Content:

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

Date  27 December 2001
     -----------------

                                 Page 13 of 15

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<PAGE>

                                    EXHIBIT 1

                                  PATENT RIGHTS

[*#*]

                                  Page 1 of 1

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<PAGE>

                                    EXHIBIT 2

                          SPONSORED RESEARCH AGREEMENT

         This Sponsored Research Agreement (the "Agreement") is made between The
University of Texas Southwestern Medical Center at Dallas ("University"), a
component institution of The University of Texas System ("System") and MYOGEN,
Inc., a Delaware corporation with its principal place of business at 7577 West
103rd Avenue, Suite 212, Westminster, CO 80021 ("Sponsor").

                                    RECITALS

         A. Concurrently with this Agreement, Sponsor and Board have entered
into a license agreement effective January 1, 2002 (the "License Agreement"),
pursuant to which the Board grants Sponsor certain licenses under inventions,
discoveries and related intellectual property rights;

         B. Sponsor desires that University perform certain research hereinafter
described and is willing to advance funds to sponsor such research;

         C. Sponsor desires to obtain certain rights to inventions, discoveries
and intellectual property developed during the course of such research with a
view to profitable commercialization of such intellectual property for the
Sponsor's benefit; and

         D. University is willing to perform such research and to grant certain
rights to such intellectual property.

                                1. EFFECTIVE DATE

         This Agreement shall be effective as of January 1, 2002 (the "Effective
Date").

                               2. RESEARCH PROGRAM

         2.1 University will conduct the research program described in
Attachment A ("Research Program"), to be amended and expanded from time to time
by the mutual written agreement of the Principal Investigator and a
representative or representatives of Sponsor designated for such purpose, and
will furnish the facilities necessary to carry out the Research Program. The
Research Program will be under the direction of [*#*] or his successor as
mutually agreed to by the parties (the "Principal Investigator") and will be
conducted by the Principal Investigator at the University. In the event
University cannot propose a successor to [*#*] who is reasonably acceptable to
Sponsor, Sponsor shall have the right to terminate the Agreement pursuant to
Section 11.2.

         2.2 The Research Program shall be performed during the period from the
Effective Date through and including December 31, 2002 ("Term"). Sponsor shall
have the option to

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negotiate an extension of the Term under mutually agreeable support terms. Such
option shall be exercised within forty-five (45) days prior to the end of the
Term.

         2.3 Sponsor understands that University's mission is advancement of
knowledge, education, and patient care and, consequently, the Research Program
will be designed to carry out that mission. The manner of performance of the
Research Program shall be determined solely by the Principal Investigator using
good faith, diligent efforts, in consultation with Sponsor. University does not
guarantee specific results.

         2.4 [*#*]

         2.5 University does not guarantee that any intellectual property rights
will result from the Research Program, that the scope of any intellectual
property rights obtained will cover Sponsor's commercial interest, or that any
such intellectual property rights will be free of dominance by others
independent of the Research Program.

                                 3. COMPENSATION

         3.1 As consideration for the performance by University of its
obligations under this Agreement, Sponsor will pay the University an amount
equal to [*#*]. An initial payment of [*#*] shall be made at the time of
execution of this Agreement, and subsequent payments shall be made [*#*].

         3.2 University shall maintain all Research Program funds in a separate
account [*#*].

         3.3 [*#*]

                           4. CONSULTATION AND REPORTS

         4.1 Sponsor's designated representative for consultation and
communications with the Principal Investigator shall be the Sponsor's Vice
President of Research and Development or such other person as Sponsor may from
time to time designate in writing to University and the Principal Investigator
("Designated Representative").

         4.2 During the Term of the Agreement, Sponsor's representatives may
consult informally with University's representatives regarding the project, both
personally and by telephone. Access to work carried on in University
laboratories in the course of these investigations shall be entirely. under the
control of University personnel but shall be made available on a reasonable
basis.

         4.3 The Principal Investigator will make oral reports at reasonable
intervals each year as requested by Sponsor's Designated Representative. At the
conclusion of each calendar quarter, the Principal Investigator shall submit to
Sponsor a written report summarizing the work. The Principal Investigator shall
also submit a comprehensive final report within one hundred twenty (120) days of
termination of the Agreement which shall contain, but which need not be limited
to, the following information:

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<PAGE>

         a. [*#*]

         b. [*#*]

                                  5. PUBLICITY

         Subject to Article 6 below, neither party shall make reference to the
other in a press release or any other written statement in connection with work
performed under this Agreement, if it is intended for use in the public media,
except as required by The Texas Public Information Act or other law or
regulation. Each party, however, shall have the right to acknowledge Sponsor's
support of the investigations under this Agreement in scientific or academic
publications and other scientific or academic communications, without the other
party's prior approval. In any such statements, the parties shall describe the
scope and nature of their participation accurately and appropriately.

                       6. PUBLICATION AND ACADEMIC RIGHTS

         6.1 University and Principal Investigator have the right to publish or
otherwise publicly disclose information gained in the course of this Agreement.
In order to avoid loss of patent rights as a result of premature public
disclosure of patentable information, University will submit any prepublication
materials to Sponsor for review and comment at least sixty (60) days prior to
planned submission for publication. Sponsor shall notify University within
thirty (30) days of receipt of such materials whether it desires University to
file patent applications on any inventions contained in the materials; and, if
requested by Sponsor, University will proceed to file a patent application in
due course, and in any event within sixty (60) days of the date of such request.
[*#*] Neither University nor Principal Investigator shall disclose any such
materials for a period extending sixty (60) days from the date Sponsor provides
notice to University that it desires University to file such related patent
application. University shall have the final authority to determine the scope
and content of any publications.

         6.2 It is understood that the Principal Investigator may discuss the
research being performed under this Agreement with other investigators but shall
not reveal information which is Sponsor's Confidential Information under Article
7. Neither University nor Principal Investigator shall involve any person in the
performance of the research being performed pursuant to this Agreement, other
than such persons as Sponsor agrees in writing may be so involved. In the event
any joint inventions result from such discussions, University shall grant to
Sponsor the rights outlined in Article 8 of this Agreement, to the extent these
are not in conflict with obligations to another party as a result of the
involvement of the other investigator(s). In this latter case, University shall,
in good faith, exercise reasonable efforts to apportion the rights to any such
joint invention between Sponsor and the investigator's third party sponsors in a
reasonable and equitable manner.

                           7. CONFIDENTIAL INFORMATION

         7.1 Subject to the terms of this Article 7, the parties may wish, from
time to time, in connection with work contemplated under this Agreement, to
disclose confidential information

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<PAGE>

to each other. All information in the Research Program and all information
contained in documents marked "confidential" and forwarded to one party by the
other ("Confidential Information") are: (i) to be held in strict confidence;
(ii) to be used only for the performance of the Research Program; and (iii) not
to be disclosed by the recipient party, its agents or employees without the
prior written consent of the disclosing party. Each party will use reasonable
efforts to prevent the disclosure of any of the other party's Confidential
Information to third parties for a period of three (3) years from receipt
thereof, provided that the recipient party's obligation shall not apply to
information that:

         (a)      is not disclosed in writing or reduced to writing and so
                  marked with an appropriate confidentiality legend within
                  thirty (30) days of disclosure;

         (b)      is already in the recipient party's possession at the time of
                  disclosure thereof;

         (c)      is or later becomes part of the public domain through no fault
                  of the recipient party;

         (d)      is received from a third party having no obligations of
                  confidentiality to the disclosing party;

         (e)      is independently developed by the recipient party; or

         (f)      is required by law or regulation to be disclosed.

         7.2 Each party may disclose the other's Confidential Information to the
extent such disclosure is reasonably necessary in filing or prosecuting patent
applications, prosecuting or defending litigation, complying with applicable
governmental, regulations or conducting pre-clinical or clinical trials,
provided that if a party is required by law or regulation to make any disclosure
of the other party's Confidential Information it will, except where
impracticable for necessary disclosures, give reasonable advance notice to the
other party to allow that party to assert whatever exclusions or exemptions may
be available to it under such law or regulation.

         7.3 Each party's obligation with respect to Confidential Information
under this Article 7 shall be fulfilled using at least the same degree of care
with the other party's Confidential Information as it uses to protect its own
Confidential Information, and in no case less than reasonable care.

                  8. PATENTS, COPYRIGHTS, AND TECHNOLOGY RIGHTS

         8.1 Title to all Intellectual Property Rights made by University
resulting from the research performed hereunder shall reside in University. Such
inventions and discoveries are and shall be licensed to Sponsor pursuant to the
terms set forth in the License Agreement.

         8.2 As used in this Section 8, the term:

         "Intellectual Property Rights" means, collectively, all trademark,
         trade name, industrial design, copyright or other industrial,
         intellectual or proprietary rights resulting from activities conducted
         by University personnel (including without limitation the Principal
         Investigator) pursuant to the Research Program, including without
         limitation all Patent Rights and Technology Rights; provided, however,
         that subject to Section 6.2, it shall not

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<PAGE>

         include any intellectual or proprietary rights that are owned by or
         contractually obligated to a third party;

         "Technology Rights" has the meaning ascribed thereto in the License
         Agreement; and

         "Patent Rights" has the meaning ascribed thereto in the License
         Agreement.

         8.3 Prosecution, maintenance and enforcement of any and all
intellectual property rights related to inventions and discoveries made by
University resulting form the research performed under this Agreement shall be
governed by the terms of the License Agreement.

                                  9. LIABILITY

         9.1 Sponsor agrees to indemnify and hold harmless System, University,
their Regents, officers, agents and employees from any liability, loss or damage
they may suffer as a result of claims, demands, costs or judgments against them
arising out of the activities to be carried out pursuant to the obligations of
this Agreement, including but not limited to the use by Sponsor of the results
obtained from the activities performed by University under this Agreement;
provided, however, that the following is excluded from Sponsor's obligation to
indemnify and hold harmless:

         a.       the failure of System, University or Principal Investigator to
                  comply with any applicable FDA or other governmental law,
                  regulation, or requirements;

         b.       the negligence or willful malfeasance of Principal
                  Investigator, University, System or any Regent, officer, agent
                  or employee of University or System; or

         c.       the infringement of the intellectual property or other
                  proprietary rights of any third party by Principal
                  Investigator, University, or any officer, agent or employee of
                  University or System.

         9.2 Both parties agree that upon receipt of a notice of claim or action
arising out of the activities to be carried out pursuant to the project
described in Attachment A, the party receiving such notice will notify the other
party promptly. Sponsor agrees, at its own expense, to provide attorneys to
defend against any actions brought or filed against University, System, their
Regents, officers, agents and/or employees with respect to the subject of the
indemnity contained herein, whether such claims or actions are rightfully
brought or filed; and subject to the statutory duty of The Texas Attorney
General, University agrees to cooperate with Sponsor in the defense of such
claim or action and the University and System shall grant Sponsor authority to
conduct such defense.

                           10. INDEPENDENT CONTRACTOR

         For the purposes of this Agreement and all services to be provided
hereunder, the parties shall be, and shall be deemed to be, independent
contractors and not agents or employees of the other party. Neither party shall
have authority to make any statements, representations or commitments of any
kind, or to take any action which shall be binding on the other party, except as
may be expressly provided for herein or authorized in writing.

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                            11. TERM AND TERMINATION

         11.1 This Agreement shall commence on the Effective Date and extend
until the end of the Term as defined in Section 2.2, unless sooner terminated in
accordance with the provisions of this Article 11.

         11.2 This Agreement may be terminated by the written agreement of both
parties. In addition, Sponsor shall have the right, at its sole discretion, to
terminate funding of the Research Program and this Agreement: (a) upon thirty
(30) days notice if University is unable to find a suitable successor to [*#*]
reasonably acceptable to Sponsor pursuant to Section 2.1; or (b) after the end
of the third calendar quarter of the first year of the Term, upon ninety (90)
days written notice (a "Termination Notice") to University asserting for reasons
stated, Sponsor deems that unsatisfactory progress by the Principal Investigator
is being made on the Research Program, provided that University has the
opportunity to cure such unsatisfactory progress within the Termination Notice
period.

         11.3 In the event that either party shall be in default of its material
obligations under this Agreement and shall fail to remedy such default within
sixty (60) days after receipt of written notice thereof, this Agreement shall
terminate upon expiration of the sixty (60) day period.

         11.4 Termination or cancellation of this Agreement shall not affect the
rights and obligations of the parties accrued prior to termination, or Sponsor's
rights under the License Agreement. Except for any termination by Sponsor
pursuant to Section 11.2(b) above, as its sole liability upon termination,
Sponsor shall pay University [*#*]

         11.5 The obligations of the parties that are contained in Sections 5,
6, 7, 8 and 9 shall survive termination of this Agreement. If for any reason
this Agreement survives the termination of the License Agreement, the parties
shall meet and discuss in good faith the terms under which Sponsor may obtain
rights in the inventions, discoveries and related Intellectual Property Rights
developed under the Research Program during the Term, which terms shall be no
less favorable than those provided under the License Agreement.

                                 12. ATTACHMENTS

         Attachment A is incorporated and made a part of this Agreement for all
purposes.

                                   13. GENERAL

         13.1 This Agreement may not be assigned by either party without the
prior written consent of the other party; provided, however, that subject to the
approval of University, which may not be unreasonably withheld, Sponsor may
assign this Agreement to any purchaser or transferee of all or substantially all
of Sponsor's assets or stock upon prior written notice to University, and
University may assign its right to receive payments hereunder.

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         13.2 This Agreement constitutes the entire and only agreement between
the parties relating to the Research Program, and all prior negotiations,
representations, agreements and understandings are superseded hereby. No
agreements altering or supplementing the terms hereof may be made except by
means of a written document signed by the duly authorized representatives of the
parties.

         13.3 Any notice required by this Agreement by Articles 9, or 11 shall
be given by prepaid, first class, certified mail, return receipt requested,
addressed in the case of University to:

         The University of Texas System, O.G.C.
         201 West 7th Street
         Austin, TX  78701
         Attention: Intellectual Property Section
         FAX: (512) 499-4523
         PHONE: (512) 499-4462

         The University of Texas Southwestern
         Medical Center at Dallas
         5323 Harry Hines Blvd.
         Dallas, TX  75390-9062
         ATTN: Shawn Cohenour
               Director, Contracts Management
         FAX: (214) 648-0845
         PHONE: (214) 648-4335

or in the case of Sponsor to:

         MYOGEN, INC.
         7577 West 103rd Avenue #212
         Westminster, CO  80021-5426
         ATTN:  J. William Freytag
         FAX: (303) 410-6667
         PHONE: (303) 410-6666

or at such other addresses as may be given from time to time in accordance with
the terms of this notice provision.

         13.4 This Agreement shall be governed by, construed, and enforced in
accordance with the internal laws of the State of Texas.

         13.5 Each party shall comply with all federal, state and local laws,
regulations and ordinances in connection with the activities it conducts under
this Agreement.

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<PAGE>

         IN WITNESS WHEREOF, the parties have caused this Agreement to be
executed by their duly authorized representatives.

<Table>
<S>                                       <C>
THE UNIVERSITY OF TEXAS                   SPONSOR
SOUTHWESTERN MEDICAL CENTER
AT DALLAS

/s/ Robert J. Alpern                      /s/ J. William Freytag
----------------------------------        ----------------------------------
Robert J. Alpern, M.D.                    J. William Freytag
Dean, Southwestern Medical School         President and CEO

Date     1/10/02                          Date     12-31-01
    ------------------------------            ------------------------------
</Table>

                                  Page 8 of 9

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<PAGE>

                                  ATTACHMENT A

                                RESEARCH PROGRAM

[*#*]

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<PAGE>

                                    EXHIBIT 3

                          MATERIALS TRANSFER AGREEMENT

The University of Texas Southwestern Medical Center at Dallas agrees to provide
__________________ with certain materials and know-how for the purposes stated
herein under the following conditions:

         1. The parties to this Agreement are: __________________, hereinafter
"RECIPIENT", and The University of Texas Southwestern Medical Center at Dallas,
hereinafter "UT SOUTHWESTERN." The RESEARCH (as hereinafter defined) will be
conducted by RECIPIENT under the supervision of hereinafter "SCIENTIST".

         2. The material that is covered by this Agreement includes: (a)
_________________________________________, which was developed by of UT
SOUTHWESTERN, and (b) any related biological material or associated know-how and
data that will be provided by UT SOUTHWESTERN or received by SCIENTIST from UT
SOUTHWESTERN, hereinafter "MATERIAL." The MATERIAL is considered proprietary to
UT SOUTHWESTERN. UT SOUTHWESTERN shall be free, in its sole discretion, to
distribute the MATERIAL to others and to use it for its own purposes.

         3. The MATERIAL shall be used by SCIENTIST in research to study
_______________________________________________ hereinafter "RESEARCH."

         4. Neither SCIENTIST nor RECIPIENT shall distribute, release, or in any
way disclose the MATERIAL to any person or entity other than laboratory
personnel under SCIENTIST'S direct supervision, and SCIENTIST and RECIPIENT
shall ensure that no one will be allowed to take or send MATERIAL to any other
location, unless written permission is obtained from UT SOUTHWESTERN. [*#*]

         5. RECIPIENT understands that the MATERIAL may be subject to certain
exclusive licensing arrangements between UT SOUTHWESTERN and Myogen, Inc.
(hereinafter "MYOGEN"). RECIPIENT agrees to use the MATERIAL solely for
research, teaching and other educationally-related, non-commercial purposes
only. [CHOOSE ONE OF THE FOLLOWING] [*#*]

         6. RECIPIENT agrees that nothing herein shall be deemed to grant to
RECIPIENT or SCIENTIST any rights under any UT SOUTHWESTERN patents or any
rights to use the MATERIAL for any products or processes for profit-making or
commercial purposes. The MATERIAL will not be used in commercially sponsored
research or research that is subject to consulting or licensing obligations of
RECIPIENT or SCIENTIST to another individual, institution or business entity
unless prior written permission is obtained from UT SOUTHWESTERN.

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         7. RECIPIENT shall have no rights in the MATERIAL other than as
provided in this Agreement. At the request of UT SOUTHWESTERN, RECIPIENT will
return all unused MATERIAL.

         8. RECIPIENT will inform UT SOUTHWESTERN, in confidence, of results of
RESEARCH related to the MATERIAL by personal written communication or by
providing UT SOUTHWESTERN with a draft manuscript describing such results. If
RECIPIENT'S SCIENTIST desires to publish such RESEARCH results in a
noncommercial scientific publication, RECIPIENT will provide UT SOUTHWESTERN
with a copy of any manuscript or abstract disclosing such RESEARCH results prior
to submission thereof to a publisher or to any third party, and in any case, not
less than forty-five (45) days prior to any public disclosure, for the purpose
of protecting the MATERIAL and any proprietary and intellectual property of UT
SOUTHWESTERN that might be disclosed by such publication. If the publication
comes about, RECIPIENT agrees to acknowledge UT SOUTHWESTERN scientists, as
academically and scientifically appropriate, based on provision of the MATERIAL
or other direct contribution to the RESEARCH. UT SOUTHWESTERN agrees that it
will acknowledge SCIENTIST'S publications, as academically and scientifically
appropriate, in its publications, which may refer to the results of SCIENTIST'S
RESEARCH.

         9. The MATERIAL is experimental in nature and it is provided WITHOUT
WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR ANY OTHER
WARRANTY, EXPRESS OR IMPLIED. UT SOUTHWESTERN MAKES NO REPRESENTATION OR
WARRANTY THAT THE USE OF THE MATERIAL WILL NOT INFRINGE ANY PATENT OR OTHER
PROPRIETARY RIGHT.

         10. In no event shall UT SOUTHWESTERN be liable for any use by
SCIENTIST or RECIPIENT of the MATERIAL or any loss, claim, damage or liability,
of whatsoever kind of nature, which may arise from or in connection with this
Agreement or the use, handling or storage of the MATERIAL. (Except where limited
by Federal law, or by the constitution and laws of the state governing the
recipient,) RECIPIENT agrees to hold harmless The University of Texas System
(hereinafter referred to as SYSTEM), UT SOUTHWESTERN, their Regents, officers,
agents and employees, from any liability, loss or damage they may suffer as a
result of claims, demands, costs or judgments against them arising out of the
activities to be carried out pursuant to this Agreement and the use by RECIPIENT
of the results obtained from RESEARCH.

         11. SCIENTIST and RECIPIENT will use the MATERIAL in compliance with
all laws, governmental regulations and guidelines applicable to the MATERIAL,
including [*#*], and when the MATERIAL is used in the United States, SCIENTIST
will comply with current NIH guidelines.

         12. This Agreement is not assignable, whether by operation of law or
otherwise, without the prior written consent of UT SOUTHWESTERN.

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<PAGE>

         13. This AGREEMENT constitutes the entire and only agreement between
the parties for MATERIAL and all other prior representations, agreements, and
understandings are superseded hereby.

<Table>
<S>                                        <C>
THE UNIVERSITY OF TEXAS                    RECIPIENT
SOUTHWESTERN MEDICAL CENTER
AT DALLAS
5323 Harry Hines Boulevard                 Address
Dallas, Texas 75350                               ---------------------------

                                            ----------------------------------

---------------------------------           ---------------------------------
Robert J. Alpern                            Name:
Dean, Southwestern Medical School           Title:

Date:                                       Date:
     ----------------------------                ----------------------------

                                            READ AND UNDERSTOOD

                                            ----------------------------------
                                            SCIENTIST
</Table>

                                   Page 3 of 3

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                                                                   EXHIBIT 10.23

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                                LICENSE AGREEMENT

         This License Agreement ("AGREEMENT") is made as of this 30th day of
June 2003 (the "EFFECTIVE DATE") by and between ABBOTT LABORATORIES, an Illinois
corporation, with its principal office at 100 Abbott Park Road, Abbott Park, IL
60064-6049 ("ABBOTT") and MYOGEN, INC., a Delaware corporation, with its
principal office at 7575 W. 103rd Avenue, Westminster, CO 80021-5426 ("MYOGEN").

                                   WITNESSETH

WHEREAS, Abbott is the holder or licensee of certain patent applications and
patents ("Patents," as more fully defined below) relating to Compound (as
defined below);

WHEREAS, Abbott also possesses proprietary Know-How (as defined below) relating
to Compound; and

WHEREAS, Myogen wishes to obtain, and Abbott wishes to grant to Myogen, an
exclusive license in the Myogen Territory (as defined below) under the Abbott
Technology (as defined below) for the development and commercialization of
Product for use in the Field (as defined below).

NOW, THEREFORE, in consideration of the mutual obligations and promises as set
forth herein, the parties do hereby agree as follows:

1.       DEFINITIONS

         In addition to the terms defined in the other provisions of this
         Agreement, as used in this Agreement, the following terms shall have
         the following respective meanings:

         1.1      "ABBOTT TECHNOLOGY" means the Patents and Know-How, including
                  all Improvements developed by Abbott and Improvements that are
                  jointly developed by Abbott and Myogen pursuant to Article 15.

         1.2      "AFFILIATE" means any corporation, company, partnership, joint
                  venture and/or firm, which controls, is controlled by, or is
                  under common control with either party hereto. For purposes of
                  this definition, control shall mean direct or indirect
                  ownership of more than fifty percent (50%) of the stock or
                  participating shares entitled to vote for the election of
                  directors (but only as long as such ownership exists).

         1.3      "API" means the Compound in an active pharmaceutical form
                  suitable for manufacture of Product.

         1.4      CANCER FIELD means the prophylactic or therapeutic
                  administration to humans or non-human animals as an agent,
                  either alone or in combination with other agents, for the
                  prevention, treatment or palliation of cancer including
                  neoadjuvant,

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                  adjuvant or supportive care and/or as part of combination with
                  radiotherapy, surgery, chemo-, biologic- or other therapy
                  associated with cancer, including, but not limited to, pain
                  and bone/skeletal complications or indications from bone
                  metastasis.

         1.5      "CO-MARKETING" means the sale by Myogen and Abbott of the same
                  formulation of a Product independently under separate trade
                  names in a particular country.

         1.6      "COMBINATION PRODUCT" means a pharmaceutical product that is
                  comprised in part of API and in part of one or more other
                  pharmaceutically active agents in any configuration,
                  formulation or combination.

         1.7      "COMMERCIALLY REASONABLE EFFORTS" means the level of efforts
                  and resources required to carry out clinical or regulatory
                  development, manufacturing, or commercialization, as
                  applicable, of Product in a manner consistent with the efforts
                  that a similarly situated pharmaceutical company would
                  typically devote to a product of similar market potential,
                  profit potential and strategic value.

         1.8      "COMPOUND" means the compound identified as LU 135252
                  (Darusentan) with the following formula:

                  [GRAPHIC FORMULA]

                  and its racemates, isomers, Prodrugs, active metabolites and
                  any pharmaceutically acceptable salt or complex thereof, in
                  its current and any other formulation, whether made before or
                  after the Effective Date.

         1.9      "CONFIDENTIAL INFORMATION" means any and all information or
                  data relating to the Compound and/or Product which a party
                  discloses to the other party, its employees or
                  representatives, including information that is conceived or
                  reduced to practice during the Term by either party or by a
                  Third Party conducting feasibility and evaluation studies for
                  Myogen, whether in writing, orally or by observation,
                  including, without limitation, all scientific, clinical,
                  technical, commercial, financial and business information and
                  Know-How, and other information or data that is identified as
                  confidential at the time it is communicated. Confidential
                  Information shall not include information or any portion
                  thereof which:

                  (a)      is known to the receiving party at the time of
                           disclosure and documented by written records made
                           prior to the date of this Agreement;

                  (b)      is subsequently disclosed to the receiving party
                           without any obligations of confidence by an
                           unaffiliated third person who has not obtained it
                           directly or indirectly from the other party and who
                           has the right to make such disclosure;

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED   2

<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                  (c)      becomes patented, published or otherwise part of the
                           public domain; or

                  (d)      is independently developed by or for the receiving
                           party by person(s) having no knowledge of or access
                           to such information and without breach of any
                           confidentiality obligation as evidenced by its
                           written records.

                  (e)      The contents of and the Exhibits to this Agreement
                           shall constitute Confidential Information.

         1.10     "CO-PROMOTION" means the joint promotion of the Product by the
                  parties under the same brand name and label.

         1.11     "CO-PROMOTION AGREEMENT" means the agreement setting forth the
                  terms governing the parties Co-Promotion arrangement, to be
                  negotiated by the Parties upon Abbott's exercise of the
                  Co-Promotion Option.

         1.12     "CO-PROMOTION OPTION" shall have the meaning ascribed to such
                  term in Section 3.1 of this Agreement

         1.13     "CO-PROMOTION TERRITORY" means [/\#/\].

         1.14     "CRD" means the medical condition commonly known as chronic
                  renal disease.

         1.15     "EFFECTIVE DATE" shall have the meaning ascribed to such term
                  in the opening paragraph of this Agreement.

         1.16     "EMEA" means the European Medicines Evaluation Agency, or any
                  successor thereto.

         1.17     "EUROPE" means all members of the European Union as of the
                  Effective Date.

         1.18     [/\#/\]

         1.19     "FIELD" means all human and non-human diagnostic, prophylactic
                  and therapeutic uses of the Compound and/or Product in any
                  formulation or dosage form for any and all indications except
                  therapeutic uses and indications in the Cancer Field.

         1.20     "FIRST COMMERCIAL SALE" means the first sale of Product in the
                  Myogen Territory, after Regulatory Approval, by Myogen, any
                  Affiliates or sublicensees of Myogen, or any contract sales
                  force of Myogen or its Affiliates, to any unaffiliated Third
                  Party as evidenced by the selling party's invoice or other
                  relevant document provided to such Third Party. A sale to an
                  unaffiliated Third Party shall not include quantities
                  delivered solely for research purposes, for clinical trials or
                  quantities distributed as free samples or promotions.

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     3
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

         1.21     "IMPROVEMENTS" means all additions, developments,
                  modifications, enhancements and adaptations (i) which directly
                  relate to or are used in connection with the Compound and/or
                  Product, or any formulations thereof or additions,
                  developments, modifications, enhancements, improvements and
                  adaptations thereto, and (ii) which are conceived or reduced
                  to practice during the Term. Ownership of Improvements shall
                  be as set forth in Article 15 hereof.

         1.22     "IND" means an investigational new drug application filed with
                  the applicable Regulatory Authority in a country of the Myogen
                  Territory, in order to commence human clinical testing of a
                  drug. An IND, together with all supplemental filings
                  referencing the initial IND filing, shall be deemed one and
                  the same IND for all purposes of this Agreement.

         1.23     "KNOW-HOW" means any proprietary technology, information,
                  method of use, process, technique, idea or invention (other
                  than the Patents) owned, possessed or used by Abbott or its
                  Affiliates as of the Effective Date which is directly related
                  to or used in connection with the Compound and/or Product,
                  including all trade secrets and any other technical
                  information relating to development, manufacture, use or sale
                  of the Compound and/or Product, provided that Abbott continues
                  to have the right to license and/or sublicense to Myogen.

         1.24     "MANUFACTURING AND SUPPLY AGREEMENT" means an agreement
                  between the parties for the manufacture and supply of Compound
                  and/or Product as contemplated and described more fully under
                  Section 6.6(b) below.

         1.25     [/\#/\]

         1.26     "MYOGEN TRADEMARK" means any trademark registered, owned or
                  chosen for Product by Myogen in any country of the Myogen
                  Territory and the Co-Promotion Territory.

         1.27     "NDA" means an application (whether original, supplementary or
                  abbreviated) to the applicable Regulatory Authority in a
                  country of the Myogen Territory, for approval by such
                  Regulatory Authority, necessary for the commercial sale of
                  Product in such country. An NDA, together with all
                  supplemental filings referencing the initial NDA filing, shall
                  be deemed one and the same NDA for all purposes of this
                  Agreement.

         1.28     "NET SALES" means gross sales of the Product invoiced to
                  unrelated third parties in arm's length transactions, by
                  Myogen or any Myogen Affiliates or sublicensees of Myogen, or
                  any contract sales force of Myogen or its Affiliates,
                  including, but not limited to, pharmaceutical wholesalers,
                  pharmacies, hospitals or dispensing physicians, less any of
                  the following charges or expenses that are incurred in
                  connection with gross sales of the Product during the Term:

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED    4
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                  (a)      discounts, including cash discounts, customary trade
                           allowances or rebates actually taken, governmental
                           rebates, chargebacks, commissions, and group
                           purchasing management fees for formulary access;

                  (b)      credits or allowances given or made for rejection,
                           recall or return of previously sold Product actually
                           taken;

                  (c)      any tax or government charge, duty or assessment
                           (including any tax such as a value added or similar
                           tax or government charge) levied on the sale,
                           transportation or delivery of Product when included
                           on the invoice or other written document between the
                           parties as payable by the purchaser and collectable
                           by Myogen, its Affiliate or sub-licensee; and

                  (d)      freight, postage, transportation, insurance and
                           duties on shipment of Product when included on the
                           invoice or other written document between the parties
                           as payable by the purchaser and collectable by
                           Myogen, its Affiliates or sublicensees.

         With respect to a Combination Product, Net Sales of such Combination
         Product shall first be calculated in accordance with Net Sales of
         Product above, and then the Net Sales of such Combination Product shall
         be determined on a country-by-country basis as follows:

                           (i)      [/\#/\]

                           (ii)     [/\#/\]

         1.29     "PATENTS" means the patent applications and patents listed in
                  Exhibit A hereto and any patents or patent applications
                  derived from those listed in Exhibit A in the sense of making
                  a priority claim to one of those listed patents or patent
                  applications, including foreign equivalents, and any and all
                  substitutions, extensions, additions, reissues,
                  re-examinations, renewals, divisions, continuations,
                  continuations-in-part or supplementary protection certificates
                  and any other patent applications and patents owned by or
                  licensed to (with the right to sublicense) Abbott or its
                  Affiliates during the Term specifically claiming the Compound
                  or Product or solely relating to any Improvements to the
                  Compound derived from Abbott Technology.

         1.30     "PRODRUG" means a pharmaceutical compound which, following
                  administration to a human, is metabolized into the Compound or
                  an Improvement.

         1.31     "PRODUCT" means any formulation containing the Compound or an
                  Improvement to the Compound as an active ingredient for use in
                  the Field.

         1.32     "REGULATORY APPROVAL" or "RA" means all governmental approvals
                  and authorizations necessary for the commercial sale of the
                  Product in a country of the

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     5
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                  Myogen Territory, including, but not limited to, marketing
                  authorization, pricing approval and pricing reimbursement, as
                  applicable.

         1.33     "REGULATORY AUTHORITY" means the United States Food and Drug
                  Administration ("FDA") or any successor entity and its
                  equivalent in other countries of the Myogen Territory,
                  including, but not limited to, the EMEA.

         1.34     [/\#/\]

         1.35     "ROYALTY PERIOD" shall have the meaning ascribed to such term
                  in Section 7.4(a) of this Agreement.

         1.36     "TERM" means the period commencing on the Effective Date and
                  terminating as set forth in Article 10 below.

         1.37     "THIRD PARTY" means any entity not a party to this Agreement
                  and not an Affiliate of Myogen or Abbott.

         1.38     "VALID CLAIM" means a claim of an unexpired Patent which
                  covers the manufacture, use or sale of the Product that has
                  not been withdrawn, canceled or disclaimed nor held to be
                  invalid or unenforceable by a court or government agency of
                  competent jurisdiction in an unappealed or unappealable
                  decision.

         1.39     "WORK PLAN" means the preliminary summary of the development
                  plan for the Product, which preliminary summary is attached
                  hereto as Exhibit B, and the final version of which will be
                  completed by Myogen, reviewed by Abbott and attached hereto as
                  the final version of Exhibit B by December 31, 2003.

2.       LICENSE GRANT

         Subject to Abbott's Co-Promotion Rights set out in this Agreement,
         Abbott hereby grants to Myogen an exclusive right and license in the
         Myogen Territory, under the Abbott Technology, for all uses in the
         Field, with the right to grant sublicenses pursuant to Section 6.7
         hereof, to (i) research, develop, modify and improve Compound and
         Product; (ii) apply for and obtain Regulatory Approvals; and (iii) use,
         import/export, market, offer to sell and sell, Product and Compound;
         and (iv) make, or have made, the Compound and Product for use in the
         Field.

3.       ABBOTT'S CO-PROMOTION RIGHTS

         3.1      Abbott shall have the right of first negotiation
                  ("CO-PROMOTION OPTION") to participate with Myogen in the
                  Co-Promotion of Product in the Co-Promotion Territory, under
                  terms and conditions to be negotiated within [/\#/\] of
                  Abbott's exercise of the Co-Promotion Option.

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     6
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

         3.2      The Co-Promotion Option shall become effective upon Myogen's
                  notice to Abbott that it intends to seek a Co-Promotion
                  arrangement in a particular country or group of countries in
                  the Myogen Territory and shall remain open for a [/\#/\]
                  period thereafter ("CO-PROMOTION OPTION PERIOD"). Abbott may
                  exercise its Co-Promotion Option by providing Myogen with
                  notice of its intention to exercise its Co-Promotion Option
                  before the expiration of the Co-Promotion Option Period. The
                  parties shall have [/\#/\] to conclude the terms of the
                  Co-Promotion arrangement in the country or countries in
                  question. If Abbott fails to give notice of its exercise or
                  its election not to exercise its Co-Promotion Option before
                  the expiration of the Co-Promotion Option Period, Abbott will
                  be deemed to have waived all rights under its Co-Promotion
                  Option. In the event Abbott waives or otherwise fails to
                  exercise its Co-Promotion Option or if the parties are unable
                  to conclude an agreement within the [/\#/\] negotiation
                  period, then Myogen shall be free to enter into such an
                  arrangement with any Third Party in that country or group of
                  countries. If Co-Promotion is not legally permitted in any
                  country of the Co-Promotion Territory, Abbott's right to
                  negotiate as set forth in this Section 3.2 will be limited to
                  Co-Marketing rights in such country or countries, the terms of
                  which shall be negotiated by the parties.

4.       JAPAN OPTION

         4.1      JAPAN OPTION. Myogen grants Abbott a right of first
                  negotiation to become Myogen's exclusive development and
                  commercialization partner of Product in Japan ("JAPAN
                  OPTION").

         4.2      The Japan Option shall become effective [/\#/\] following the
                  enrollment of the first patient in the first clinical trial as
                  outlined in the Work Plan and shall remain open for a sixty
                  (60) day period thereafter ("JAPAN OPTION PERIOD"). Abbott may
                  exercise its Japan Option by providing Myogen with notice of
                  its intention to exercise its Japan Option before the
                  expiration of the Japan Option Period. The parties shall have
                  sixty (60) days to conclude the terms of the development and
                  commercialization arrangement for Japan. If Abbott fails to
                  give notice of its exercise or its election not to exercise
                  its Japan Option before the expiration of the Japan Option
                  Period, Abbott will be deemed to have waived all rights under
                  its Japan Option. In the event Abbott waives or otherwise
                  fails to exercise its Japan Option within the Japan Option
                  Period or if the parties are unable to conclude an agreement
                  within the sixty (60) day negotiation period, then Myogen
                  shall be free to enter into such an arrangement with any Third
                  Party in Japan.

5.       INFORMATION

         5.1      CONVEYANCE OF INFORMATION/INVENTORY.

                  (a)      By June 30, 2003, Abbott shall convey to Myogen or
                           its designee all the information under Abbott's or
                           its Affiliates' control relating to the

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     7
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                           Compound (the "DATA TRANSFER"). Abbott shall use
                           Commercially Reasonable Efforts to ensure that it has
                           located and conveyed all of the information under its
                           and its Affiliates' control and Abbott agrees to
                           immediately convey to Myogen any information which
                           Abbott locates after June 30, 2003. The information
                           to be transferred and conveyed as part of the Data
                           Transfer includes, but is not limited to: (i) all
                           information relating to Patents and Know-How; (ii)
                           worldwide regulatory documentation for the Compound,
                           including, without limitation, complete copies of all
                           existing IND filings for any Product, all supplements
                           thereto and all other regulatory files and FDA
                           correspondence related to any Product; (iii) clinical
                           trial protocols, draft and final clinical reports,
                           case report forms from clinical trials; (iv) safety
                           data, toxicity study reports; (v) data and
                           information related to all indications, doses, and
                           formulations, both actual and proposed, for the
                           Products; (vi) manufacturing protocols, batch records
                           and current standard operating procedures, including,
                           but not limited to, quality analysis and quality
                           control methodologies and standards; (vii) claims
                           related to potential violations of any Third Party
                           rights; and (viii) all collaborative research
                           agreements; in each case, to the extent in the
                           control of Abbott, its Affiliates and agents. For
                           purposes of this Section 5.1, information shall not
                           be deemed under Abbott's and its Affiliates' control
                           if such information is protected by confidentiality
                           agreements with third parties; provided, however,
                           that Abbott shall provide Myogen with notice that
                           such information is subject to third party
                           confidentiality obligations at the time of its
                           identification. With respect to such protected
                           information, Abbott shall use Commercially Reasonable
                           Efforts to obtain the consent of such third parties
                           to release the protected information to Myogen.

                  (b)      By June 30, 2003, Abbott will execute and deliver a
                           letter to the FDA authorizing the transfer of the IND
                           filing for the Compound to Myogen and authorizing
                           Myogen to do and take all actions that are necessary
                           to transfer the IND filings for the Compound in the
                           name of Myogen. In addition, during the [/\#/\] day
                           period following the Effective Date Abbott shall
                           provide at an Abbott location to be identified by
                           Abbott reasonable assistance to Myogen, [/\#/\] to
                           Myogen, to affect the orderly transfer of
                           Product-related development activities and regulatory
                           documents to Myogen provided that Myogen shall be
                           responsible for its own out of pocket expenses.

                  (c)      Abbott will complete, at Abbott's expense, two
                           ongoing studies nearing completion as of the
                           Effective Date, [/\#/\]. Abbott will complete, at
                           Abbott's option, but subject to Myogen's approval of
                           the applicable expenditures, any of the pre-clinical
                           studies identified on

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED      8
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                           Exhibit C for the Compound, and Myogen will reimburse
                           Abbott for [/\#/\] associated with such studies.

                  (d)      By June 30, 2003, Abbott shall, for the purposes of
                           supplying Myogen with Compound for use in conducting
                           clinical trials and at Myogen's expense, initiate the
                           process of re-testing and re-qualifying the Compound
                           and releasing to Myogen the specified quantities of
                           previously manufactured bulk API (Compound)
                           consisting of approximately [/\#/\] of Compound
                           located at Abbott's Ludwigshafen facility. Abbott
                           shall convert re-qualified Compound into tablet form
                           as well as provide matching placebos at Abbott's
                           [/\#/\] plus Abbott's [/\#/\]of Compound in such
                           tablets [/\#/\] according to a manufacturing,
                           delivery and payment schedule to be mutually agreed
                           by the parties. If Abbott is unable to re-qualify the
                           previously manufactured bulk API, Abbott shall,
                           within a Commercially Reasonable time, manufacture a
                           new batch of API sufficient to allow Myogen to
                           commence its clinical trials at Abbott's [/\#/\].
                           Abbott hereby states that its fully burdened costs
                           for the manufacture of the existing API is [/\#/\].
                           Abbott shall use commercially reasonable efforts to
                           maintain the cost of the bulk API at a cost equal to
                           or less than [/\#/\]. Myogen shall pay Abbott
                           [/\#/\].

                  (e)      Myogen shall, [/\#/\] identify which batches of the
                           existing API they wish Abbott to hold for Myogen's
                           future purchase, and Abbott shall be free to dispose
                           of all batches not so identified. Myogen may purchase
                           quantities of API from time to time on an as-needed
                           basis. Myogen [/\#/\].

                  (f)      Abbott represents and warrants that the Compound,
                           matched placebo and Product conveyed to Myogen under
                           Section 5.1(d) has been or shall be manufactured in
                           accordance with current Good Manufacturing Practices
                           ("CGMP"). Other than the foregoing warranty, any
                           Compound shall be conveyed "AS IS" and "WITH ALL
                           FAULTS," WITHOUT ANY OTHER WARRANTY OF ANY KIND
                           WHATSOEVER, EXPRESS OR IMPLIED, INCLUDING WARRANTIES
                           OF MERCHANTABILITY AND FITNESS FOR PARTICULAR
                           PURPOSE. Myogen shall be responsible for all testing,
                           quality control and certification of such Compound.

6.       FEASIBILITY/EVALUATION/DEVELOPMENT/MANUFACTURING/MARKETING/OTHER

         6.1      FEASIBILITY/EVALUATION STUDIES. Myogen shall use Commercially
                  Reasonable Efforts to evaluate the Compound in accordance with
                  the Work Plan. Myogen shall have sole responsibility for
                  conducting and/or supervising the feasibility and evaluation
                  studies on the Compound as set forth in the Work Plan. Myogen
                  shall provide Abbott with summaries of the feasibility and
                  evaluation studies conducted

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED      9
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                  by or on behalf of Myogen, including summaries of reports and
                  data generated under such studies, on a semi-annual basis
                  (including at any annual review meeting held pursuant to
                  Section 6.2 below), and all such information shall be treated
                  as Myogen's Confidential Information. Recognizing that certain
                  work to be conducted on behalf of Myogen will be performed by
                  one or more Third Parties and recognizing that such work
                  (e.g., formulations) may involve the patented subject matter
                  of such Third Party, Myogen will use Commercially Reasonable
                  Efforts to: (a) provide in its license with the Third Party
                  that the patented subject matter of such Third Party may be
                  sublicensed to Abbott in the event that the Compound and
                  Product are returned to Abbott under Sections 6.3(b) and
                  Article 10; and (b) negotiate a [/\#/\] with such Third Party.
                  In the event that Myogen is unable to negotiate a royalty-free
                  license/sublicense, Abbott agrees to [/\#/\] thereunder if it
                  elects to practice under such license/sublicense following the
                  return of the Compound and Product under Sections 6.3(b) and
                  Article 10. Myogen agrees to promptly provide Abbott with
                  written notice of the terms of any [/\#/\] prior to entering
                  into any such [/\#/\] with Third Parties, which pertain to the
                  Compound and/or Product, in order for Abbott to have the
                  opportunity to comment on said terms and conditions before
                  Myogen enters into that [/\#/\].

         6.2      REVIEW. Beginning six (6) months following the Effective Date
                  and every six (6) months thereafter while Myogen is developing
                  the Compound, Myogen shall provide Abbott with a written
                  report reviewing the progress of the Work Plan and the results
                  of such work and studies remaining to be completed under the
                  Work Plan, which report shall be deemed Myogen Confidential
                  Information. In the event Abbott so requests, the parties
                  shall meet in person once during each calendar year to discuss
                  these topics. The meeting shall be held at a mutually
                  agreeable time at Myogen's headquarters. Each party shall be
                  responsible for its own costs of attendance.

         6.3      CLINICAL DEVELOPMENT.

                  (a)      Myogen shall use Commercially Reasonable Efforts to
                           develop the Compound in accordance with the Work Plan
                           and not to materially deviate from the time schedule
                           stated therein except as may be dictated by valid
                           scientific, clinical and/or Regulatory circumstances
                           and shall use Commercially Reasonable Efforts to
                           maximize the commercial opportunity of the Compound
                           and Product. Myogen may modify the Work Plan if
                           required to adjust the Work Plan under such
                           circumstances and will communicate such modifications
                           to Abbott. If Myogen requires any other material
                           modification to the Work Plan, it will so notify
                           Abbott within a reasonable time. Myogen shall have
                           sole responsibility for designing, conducting and
                           paying for the cost of the clinical development of
                           Product and shall use Commercially Reasonable Efforts
                           to conduct such

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     10
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                           clinical development as set forth below. Abbott
                           hereby agrees that [/\#/\].

                  (b)      In the event Myogen breaches a material obligation
                           under Section 6.3(a) or 6.5(b) of this Agreement,
                           Abbott may then advise Myogen that Abbott believes
                           that Myogen has breached such material obligation and
                           that Abbott is adversely impacted thereby. Upon so
                           advising Myogen, either Party may initiate an
                           alternative dispute resolution procedure ("ADR") as
                           set forth in Exhibit D and request the ADR to rule
                           upon whether Myogen has breached any such material
                           obligation. In the event that the neutral conducting
                           such ADR renders a ruling that Myogen has breached
                           such material obligation and that Abbott was
                           adversely impacted thereby, and Myogen fails to
                           comply with the terms of the neutral's ruling within
                           the time specified therein for compliance (which in
                           no event shall be less than ninety (90) days), or if
                           such compliance cannot be fully achieved by such
                           date, Myogen has failed to commence compliance and/or
                           has failed to use diligent efforts to achieve full
                           compliance as soon thereafter as is reasonably
                           possible, then Abbott's sole remedy shall be the
                           right to terminate this Agreement and the licenses
                           granted hereunder, and to obtain from Myogen a
                           license to Improvements under Section 15.

         6.4      COMMERCIALIZATION.

                  (a)      Myogen shall use Commercially Reasonable Efforts to
                           develop, register and commercialize Product in the
                           [/\#/\]. It is the parties' expectation that Myogen
                           will commercialize Product in all commercially viable
                           markets in the [/\#/\] other than the [/\#/\] within
                           [/\#/\] following First Commercial Sale of the
                           Product. If, following such [/\#/\] period, there
                           remain markets outside the [/\#/\] where Myogen is
                           not commercializing Product which Abbott, in its
                           reasonable estimation, believes are commercially
                           viable markets, then the parties shall meet within
                           thirty (30) days of Abbott's written notice for the
                           purpose of developing a mutually agreeable action
                           plan for such under-served markets. If the parties
                           are unable to agree on an action plan, Myogen shall
                           have the option to enlist a marketing partner to
                           assist Myogen in marketing the Product in the
                           underserved markets, or to offer to Abbott the
                           option, for Abbott and its Affiliates, to sell the
                           Product directly in each such country, by paying to
                           Myogen or its sublicensees a reasonable royalty to be
                           mutually agreed by the Parties. Myogen agrees to
                           provide Product to Abbott and its Affiliates for sale
                           in

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED       11
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                           each such country at the same delivered [/\#/\] of
                           goods (as evidenced by Myogen's internal records)
                           incurred by Myogen in procuring or manufacturing
                           Product for its own sales plus [/\#/\] and to
                           cooperate with Abbott by, among other things, working
                           with Abbott and its Affiliates to coordinate, in the
                           relevant country, marketing and sales strategies and
                           the development of selling and other materials
                           necessary for the effective sale and marketing of
                           Product in such country consistent with Myogen's
                           global Product marketing strategies. The rights and
                           obligations of the parties with respect to
                           commercialization within the [/\#/\] will be as
                           agreed upon and set forth in the Co-Promotion
                           Agreement.

                  (b)      If there is any material disagreement between the
                           parties concerning whether a market is commercially
                           viable such that Myogen should be commercializing
                           Product in accordance with Section 6.4(a) hereof, or
                           if Myogen reasonably believes that enlisting a
                           marketing partner (including Abbott) to assist it in
                           selling the Product in a particular country will have
                           a substantial negative impact on Myogen's local,
                           regional or global commercial efforts, then the
                           matter may be submitted to ADR. If the neutral
                           conducting such ADR makes a final determination that
                           a market is commercially viable and that Myogen
                           should be commercializing Product in such market, the
                           neutral shall provide Myogen with the opportunity to
                           commercialize Product in such market. If Myogen fails
                           to commercialize Product within the time period
                           prescribed by the neutral (which in no event shall be
                           less than ninety (90) days), then the neutral may
                           issue an order allowing Abbott to terminate Myogen's
                           license with respect to that country.

         6.5      MARKETING/MARKETING PLAN/REGULATORY REVIEWS.

                  (a)      Except as set forth in Articles 3 and 4 above, in the
                           Myogen Territory and subject to Abbott's [/\#/\]
                           rights, if any, Myogen shall have sole responsibility
                           for marketing Product, including entering into any
                           co-marketing and/or co-promotion arrangement. Myogen
                           shall distribute all Product samples in the United
                           States in accordance with the Prescription Drug
                           Marketing Act.

                  (b)      Subject to the terms of any [/\#/\] arrangement
                           between Myogen and Abbott, six months prior to launch
                           in any of the [/\#/\], Myogen shall prepare a
                           marketing plan ("Marketing Plan"), with regard to the
                           marketing and sale of the Product. The Marketing Plan
                           shall contain a ten year sales forecast for each
                           indication for the [/\#/\], a detailed summary of the
                           size of the sales force to be utilized in the sale of
                           the Product, and detailed estimate of the promotional
                           spending to be allocated to the promotion of the
                           Product. Myogen shall on a commercially reasonable
                           basis enlist the

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                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                           services of professional consultants normally used in
                           the development of similar marketing plans for
                           products similar to Product. Abbott shall have the
                           opportunity to review said Marketing Plan
                           sufficiently in advance of its finalization in order
                           to provide comments to said Marketing Plan. Myogen
                           shall ensure that the Marketing Plan is sufficient to
                           maximize the commercial opportunity of Darusentan and
                           shall use Commercially Reasonable Efforts to
                           implement such Marketing Plan.

                  (c)      Myogen shall, at its sole expense and consistent with
                           its obligations under Section 6.4(a), apply for RA's
                           in all countries in the Myogen Territory for the
                           purposes of selling the Product.

         6.6      MANUFACTURING.

                  (a)      Myogen will be solely responsible for and/or will
                           arrange for the manufacture of Compound and/or
                           Product. Abbott shall provide Myogen with the
                           manufacturing protocol for the Compound and/or
                           Product, which protocol shall be considered Abbott
                           Confidential Information. All additional Know-How or
                           Abbott Confidential Information relating to raw
                           materials or precursors to the Compound, and all
                           additional information and documentation in Abbott's
                           or its Affiliates' possession, which are necessary to
                           make Compound and/or Product, shall be transferred to
                           Myogen by June 30, 2003.

                  (b)      If Myogen elects to negotiate terms and conditions
                           with a Third Party manufacturer ("TPM") for the
                           manufacture and supply of the Compound and/or Product
                           to Myogen, Myogen shall first offer Abbott the
                           opportunity to negotiate a Manufacturing and Supply
                           Agreement providing for Abbott to supply Myogen with
                           its requirements of the Compound and Product. The
                           parties shall have [/\#/\] to execute a definitive
                           Manufacturing and Supply Agreement. If the parties
                           are unable to conclude a definite Manufacturing and
                           Supply Agreement, then Myogen shall be free to
                           negotiate such an agreement with a TPM. Myogen shall
                           be solely responsible for all costs and expenses
                           necessary to qualify such TPM. Myogen may provide the
                           manufacturing protocol to the TPM under terms that
                           provide for the protection of Abbott Confidential
                           Information.

         6.7      SUBLICENSING. Subject to Abbott's Co-Promotion rights, Myogen
                  may sublicense its rights under this Agreement, in the Myogen
                  Territory, without obtaining Abbott's prior written consent.
                  Each sublicense shall be in writing and shall include
                  provisions acknowledging that such sublicense is subject to
                  the license granted Myogen under this Agreement, that each
                  sublicensee shall make reports and keep and maintain records
                  of sales to at least the same extent as required under this
                  Agreement, allowing Abbott the same access and audit rights as
                  permitted under this Agreement, and that such sublicense shall
                  be automatically

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                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                  terminated upon termination of this Agreement. Myogen shall
                  remain primarily liable for the performance of sublicensees.
                  Myogen shall provide Abbott with a copy of each sublicense
                  agreement.

7.       FINANCIALS

         7.1      EXECUTION LICENSE FEE. Myogen shall pay to Abbott a
                  non-refundable payment of Three Million Dollars ($3,000,000)
                  in cash on the Effective Date.

         7.2      SECOND LICENSE FEE PAYMENT. Myogen shall convey to Abbott a
                  non-refundable payment of Two Million Dollars ($2,000,000) in
                  cash on or before December 31, 2003.

         7.3      MILESTONES. Myogen shall make the following [/\#/\] milestone
                  payments ("Milestones") to Abbott within [/\#/\] of the
                  occurrence of the following events with respect to any
                  Product, regardless of whether or not Myogen has sublicensed
                  any of its rights under this Agreement:

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                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

REGULATORY FILING MILESTONE                                           PAYMENT

Submission of first filing of an NDA in [/\#/\]:                      [/\#/\]

Submission of first filing seeking Regulatory                         [/\#/\]
Approval in [/\#/\]:

REGULATORY APPROVAL MILESTONE                                         PAYMENT

First Indication:

Upon Regulatory Approval in [/\#/\]:                                  [/\#/\]
Upon Regulatory Approval of an [/\#/\] filing or approval in
[/\#/\]:                                                              [/\#/\]
Upon Regulatory Approval in [/\#/\]:                                  [/\#/\]

Second Indication:

Upon Regulatory Approval in [/\#/\].:                                 [/\#/\]
Upon Regulatory Approval of an [/\#/\] filing or approval in
[/\#/\]:                                                              [/\#/\]
Upon Regulatory Approval in [/\#/\]:                                  [/\#/\]

Third Indication:

Upon Regulatory Approval in [/\#/\]:                                  [/\#/\]
Upon Regulatory Approval of an [/\#/\] filing or approval in
[/\#/\]:                                                              [/\#/\]
Upon Regulatory Approval in [/\#/\]:                                  [/\#/\]

Each milestone payment will be made only once regardless of how many Products
are developed or commercialized or the number of indications for which a Product
has received Regulatory Approval. The total maximum milestone payments and
license fees due Abbott with respect to any and all Products if all of the
foregoing milestones are met will be [/\#/\].

For purposes of this Section 7.3 the term "Indication" with respect to Second
Indication and Third Indication refers to a new indication for the use of an
existing, approved Product for which (a) an additional clinical trial must be
conducted with the Product in order to obtain Regulatory Approval for such use;
and (b) where such Regulatory Approval results in a Regulatory
Authority-approved label expanding the approved uses of the Product.

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                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

         7.4      ROYALTY PAYMENTS.

                  (a)      MARGINAL ROYALTY RATE AND ROYALTY PERIOD. Beginning
                           with the [/\#/\] Myogen shall pay to Abbott a royalty
                           on annual aggregate worldwide Net Sales of all
                           Product in accordance with the following schedule:

                           ANNUAL NET SALES            MARGINAL ROYALTY RATE

                           [/\#/\]                            [/\#/\]
                           [/\#/\]                            [/\#/\]
                           [/\#/\]                            [/\#/\]

                           In those countries where no Valid Claim exists at the
                           time of launch of the Product covering the Compound
                           or any Product, Myogen will pay Abbott a royalty of
                           [/\#/\] of Myogen's Net Sales in such country in
                           consideration for licenses to Abbott Know-How
                           relating to the Compound or Product for a period of
                           not more than [/\#/\] after Regulatory Approval of
                           the Product in such country; provided however, if
                           during the Term a Valid Claim comes into existence
                           for any such country, then the normal royalty rate
                           shall apply to sales in that country unless generic
                           competition to the Product exists in that country and
                           the generic product has at least a [/\#/\] market
                           share in that country, in which case the reduced
                           royalty rate shall apply for the [/\#/\] period
                           described above for so long as the generic product
                           has a [/\#/\] market share, provided however, if the
                           market share of the generic product drops below
                           [/\#/\] during such [/\#/\] period, the normal
                           royalty rate shall again apply for so long as the
                           market share of the generic product is below [/\#/\].

                           The obligation of Myogen to pay a full royalty to
                           Abbott shall be on a country-by-country basis and
                           shall continue with respect to Product manufactured
                           or sold in a country until the expiration of the last
                           Patent in such country that contains a Valid Claim
                           (the "ROYALTY PERIOD").

                  (b)      REDUCED ROYALTY. Upon the end of the Royalty Period
                           in any country of the Myogen Territory on a
                           country-by-country basis, Myogen shall have an
                           exclusive, perpetual and irrevocable license under
                           the Abbott Technology in such country of the Myogen
                           Territory, with all of the rights granted under
                           Article 2 hereof, except that, for a period of
                           [/\#/\] from the expiration of the Valid Claim in
                           that country, Myogen shall pay to Abbott a reduced
                           royalty of [/\#/\] of Net Sales of Product in such
                           country (the "REDUCED ROYALTY PERIOD").

                  (c)      ROYALTY REPORTS AND PAYMENTS. Beginning with the
                           [/\#/\], within forty-five (45) days after the end of
                           each calendar quarter, Myogen shall

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                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                           prepare and deliver to Abbott a report detailing the
                           calculation of Net Sales, on a country-by-country
                           basis, for such just ended quarter along with the
                           calculation of royalties due thereon pursuant to
                           Sections 7.4(a) and (b) above. Each report shall be
                           accompanied by full payment in U.S. dollars of the
                           royalties shown thereon to be due. In the event that
                           conversion from foreign currency is required in
                           calculating a royalty payment hereunder, the exchange
                           rate used shall be the average of the ratio in effect
                           on the first business day and the last business day
                           of the applicable quarter for which royalties are
                           calculated, as reported at the 9:00 am (Central
                           Standard Time) exchange rate according to Reuters, or
                           a substantially similar global publication if Reuters
                           is no longer published. All such quarterly reports
                           shall show sales in the currency of the country in
                           which the sales were made and the currency conversion
                           rate used to arrive at the US dollar amounts shown in
                           the quarterly report.

                  (d)      BOOKS AND RECORDS/AUDIT RIGHTS. Myogen shall keep
                           books and records accurately showing all Products
                           manufactured, used or sold under the terms of this
                           Agreement. The relevant portions of such books and
                           records shall be open to inspection by
                           representatives of Abbott, at Abbott's cost, solely
                           for the purposes of determining the correctness of
                           the royalties payable under this Agreement. Such
                           audit, conducted no more than one time per calendar
                           year, shall be during normal business hours after
                           reasonable advance notice and subject to suitable
                           confidentiality provisions. In the event an audit
                           shows a deficiency to be due, Myogen shall
                           immediately pay such deficiency along with the
                           reasonable costs and expenses of the audit if the
                           deficiency is more than five percent (5%) of the
                           amount due during such audited period. If the audit
                           shows that an excess was paid, Myogen shall be
                           entitled to deduct the amount of such excess from the
                           payment due for the next calendar quarter. Such books
                           and records shall be preserved for a period of at
                           least three (3) years after the date of the royalty
                           payment to which they pertain, and no audit may be
                           conducted with respect to royalties due in any
                           calendar year that is more than two (2) years
                           preceding the calendar year in which the audit is
                           being conducted. Books and records for a given
                           calendar year may only be audited once.

                  (e)      WITHHOLDING TAXES ON ROYALTIES. Where any sum due to
                           be paid to Abbott hereunder is subject to any
                           withholding or similar tax, the parties shall use all
                           reasonable efforts to do all such acts and things and
                           to sign all such documents as will enable them to
                           take advantage of any available exemption, applicable
                           double taxation agreement or treaty. In the event
                           there is no exemption or applicable double taxation
                           agreement or treaty, or if an applicable double
                           taxation agreement or treaty reduces but does not
                           eliminate such withholding or similar tax, Myogen
                           shall pay such

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                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                           withholding or similar tax to the appropriate
                           government authority, deduct the amount paid from the
                           amount due Abbott and secure and send to Abbott proof
                           of such payment, together with copies of all relevant
                           correspondence with such government authority.

                  (f)      THIRD PARTY ROYALTIES. In the event that Myogen is
                           required to pay royalties to a Third Party under
                           patents in any country owned or controlled by such
                           Third Party, Myogen will be entitled to deduct
                           [/\#/\] of such Third Party royalties against royalty
                           payments due to Abbott; provided that royalties due
                           to Abbott shall not be reduced by greater than
                           [/\#/\] and provided further that a license under
                           such Third Party patents is necessary in order to
                           market any Product in said country. Notwithstanding
                           the foregoing, prior to the Effective Date, Abbott
                           has provided to Myogen a list of any known royalties
                           that are owed to Third Parties as of the Effective
                           Date along with copies of any agreements with Third
                           Parties pursuant to which such royalties are owed,
                           and Myogen shall have no liability with respect to
                           and shall have no obligation to pay any such Third
                           Party royalty obligations incurred with respect to
                           the Product prior to the Effective Date.

                  (g)      LATE PAYMENTS. Any payments due under this Agreement,
                           which are late, shall bear interest at the rate of
                           one percent (I%) per month.

8.       REPRESENTATIONS/WARRANTIES

         8.1      REPRESENTATIONS AND WARRANTIES OF ABBOTT. Abbott represents
                  and warrants that:

                  (a)      it is duly organized, validly existing and in good
                           standing under the laws of Illinois, that it has full
                           corporate power and authority to enter into this
                           Agreement and to carry out its provisions, and that
                           there are no outstanding agreements, assignments or
                           encumbrances in existence that are inconsistent with
                           the provisions of this Agreement;

                  (b)      it is duly authorized to execute and deliver this
                           Agreement and to perform its obligations hereunder
                           and that the execution, delivery and performance of
                           this Agreement by it does not require the consent,
                           approval or authorization of or notice, filing or
                           registration with any governmental agency or
                           Regulatory Authority;

                  (c)      as of the Effective Date, to the best of Abbott's
                           knowledge, (i) it has sufficient rights under the
                           Abbott Technology necessary to grant the rights
                           specified in this Agreement and to perform its
                           obligations hereunder; (ii) there are no claims,
                           judgments or settlements against or owed by it
                           relating to the Abbott Technology; (iii) the exercise
                           of Myogen's rights to

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                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                           the Compound under this Agreement or Myogen's use of
                           the Abbott Technology under this Agreement will not
                           infringe any intellectual property rights of a Third
                           Party with the exception of infringement arising from
                           the use of Compound or Abbott Technology in
                           combination with the technology of a Third Party and
                           such infringement would have been avoided without
                           such combination; (iv) the material provided to
                           Myogen concerning the manufacturing process for the
                           Compound as it relates to process historical cost,
                           historical yield and historical quality are accurate
                           in all material respects; (v) there are no known
                           adverse events that have not been described in the
                           documents provided to Myogen or the applicable
                           Regulatory Authority; (vi) Abbott has exerted
                           Commercial Reasonable Efforts to gather and convey to
                           Myogen all documents in Abbott's or its Affiliates'
                           possession and notices from Regulatory Authorities as
                           part of the Data Transfer described in Article 5.1
                           (a); and (vii) Exhibit A includes the relevant
                           Patents necessary to market and sell the Product as
                           contemplated in the Work Plan.

                  (d)      as of the Effective Date, to the best of Abbott's
                           knowledge, (i) none of the Patents are invalid or
                           unenforceable, (ii) it has complied in all material
                           respects with all applicable laws and regulations in
                           connection with the preparation and submission of any
                           filings with any Regulatory Authority; (iii) it has
                           filed with applicable Regulatory Authorities all
                           required and material notices, supplemental
                           applications and annual or other reports, including
                           adverse experience reports, with respect to the
                           Compound; and (iv) there is no pending or overtly
                           threatened action by the Regulatory Authorities that
                           will have a material adverse effect on the timing of
                           a Regulatory Approval of the Compound or any
                           Products.

         8.2      REPRESENTATIONS AND WARRANTIES OF MYOGEN. Myogen represents
                  and warrants that it is duly organized, validly existing and
                  in good standing under the laws of Delaware, that it has full
                  corporate power and authority to enter into this Agreement and
                  to carry out its provisions, and that there are no outstanding
                  agreements, assignments or encumbrances in existence that are
                  inconsistent with the provisions of this Agreement. Myogen
                  further represents and warrants that it is duly authorized to
                  execute and deliver this Agreement and to perform its
                  obligations hereunder, and that the execution, delivery and
                  performance of this Agreement by it does not require the
                  consent, approval or authorization of or notice, filing or
                  registration with any governmental agency or Regulatory
                  Authority.

         8.3      INDEMNIFICATION BY MYOGEN. Myogen shall indemnify and hold
                  Abbott, its Affiliates and their directors, officers,
                  employees and agents harmless from and against any and all
                  liabilities, actions, suits, claims, demands, prosecutions,
                  damages, costs, expenses or money judgments finally awarded
                  (including

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                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                  reasonable legal fees) (collectively, "LIABILITIES") incurred
                  by or instituted or rendered against Abbott to the extent such
                  Liabilities result from a Third Party claim arising from
                  product liability claims or from the willful misconduct or the
                  negligent acts or omissions of Myogen or its Affiliates or
                  Myogen's material breach of this Agreement, except to the
                  extent such Third Party claims arise out of the negligence or
                  willful misconduct of Abbott, its Affiliates and their
                  directors, officers, employees and agents, or the material
                  breach of this Agreement or the Manufacturing and Supply
                  Agreement, if any, by Abbott, its Affiliates and their
                  directors, officers, employees and agents, and provided that
                  Abbott gives Myogen prompt notice in writing of any such claim
                  or lawsuit and permits Myogen to undertake sole control of the
                  defense and settlement thereof at Myogen's expense. In any
                  such claim or lawsuit:

                  (a)      Abbott will cooperate in the defense by providing
                           access to witnesses and evidence available to it.
                           Abbott shall have the right to participate, at its
                           expense, in any defense to the extent that in its
                           reasonable judgment Abbott may be prejudiced by
                           Myogen's sole defense thereof.

                  (b)      With respect to this Agreement, Abbott shall not
                           settle, offer to settle or admit liability in any
                           claim or suit in which Abbott intends to seek
                           indemnification by Myogen without the written consent
                           of the CEO, COO or CFO of Myogen.

         8.4      INDEMNIFICATION BY ABBOTT. Abbott shall indemnify and hold
                  Myogen, its Affiliates and their directors, officers,
                  employees and agents harmless from and against any and all
                  Liabilities, incurred by or instituted or rendered against
                  Myogen to the extent such Liabilities result from a Third
                  Party claim arising from the willful misconduct or the
                  negligent acts or omissions of Abbott or its Affiliates or
                  Abbott's material breach of this Agreement, except to the
                  extent such Third Party claims arise out of the negligence or
                  willful misconduct of Myogen, its Affiliates and their
                  directors, officers, employees and agents, or the material
                  breach of this Agreement by Myogen, its Affiliates and their
                  directors, officers, employees and agents, and provided that
                  Myogen gives Abbott prompt notice in writing of any such claim
                  or lawsuit and permits Abbott to undertake sole control of the
                  defense and settlement thereof at Abbott's expense. In any
                  such claim or lawsuit:

                  (a)      Myogen will cooperate in the defense by providing
                           access to witnesses and evidence available to it.
                           Myogen shall have the right to participate, at its
                           expense, in any defense to the extent that in its
                           reasonable judgment Myogen may be prejudiced by
                           Abbott's sole defense thereof

                  (b)      With respect to this Agreement, Myogen shall not
                           settle, offer to settle or admit liability in any
                           claim or suit in which Myogen intends to seek

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                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                           indemnification by Abbott without the written consent
                           of a duly authorized officer of Abbott.

         8.5      REPORTABLE OCCURRENCES. Each party warrants that it shall
                  advise the other promptly of any occurrence, which is reported
                  or reportable by it to the Regulatory Authorities relating in
                  any way to the Compound or the Product.

         8.6      LIMITATION. EXCEPT FOR THE EXPRESS WARRANTIES IN THIS ARTICLE
                  8, NEITHER PARTY MAKES ANY WARRANTIES, EXPRESS OR IMPLIED, IN
                  FACT OR BY OPERATION OF LAW, STATUTORY OR OTHERWISE. EACH
                  PARTY SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTY OF
                  MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. EXCEPT
                  FOR VIOLATIONS OF ARTICLE 9 AND AMOUNTS FINALLY AWARDED FOR
                  INDEMNIFICATION FOR THIRD PARTY LIABILITIES UNDER SECTIONS 8.3
                  AND 8.4 ABOVE, NEITHER PARTY SHALL BE LIABLE TO THE OTHER
                  PARTY HERETO FOR ANY SPECIAL, CONSEQUENTIAL, EXEMPLARY OR
                  INCIDENTAL DAMAGES (INCLUDING LOST OR ANTICIPATED PROFITS
                  RELATING TO THE SAME) ARISING FROM ANY CLAIM RELATING TO THIS
                  AGREEMENT, WHETHER SUCH CLAIM IS BASED ON CONTRACT, TORT
                  (INCLUDING NEGLIGENCE) OR OTHERWISE, EVEN IF AN AUTHORIZED
                  REPRESENTATIVE OF SUCH PARTY IS ADVISED OF THE POSSIBILITY OR
                  LIKELIHOOD OF SAME.

9.       CONFIDENTIALITY AND NON-DISCLOSURE

         9.1      NONDISCLOSURE. Neither party shall use or disclose any
                  Confidential Information received by it from the other party
                  pursuant to this Agreement without the prior written consent
                  of the other. This obligation will continue for a period of
                  seven (7) years after termination of this Agreement or
                  expiration of the Term, whichever is earlier. Subject to the
                  exceptions immediately below, Abbott shall hold in confidence
                  and shall not directly or indirectly disclose or provide to
                  any Third Party information pertaining to the Compound or
                  Abbott Technology without Myogen's prior written consent. The
                  parties recognize that pursuant to Articles 3 and 4, Abbott
                  may be involved in marketing and selling the Compound and
                  Product in the Co-Promotion Territory. Abbott shall be
                  permitted to disclose information pertaining to the Compound
                  and the Abbott Technology to the extent necessary for Abbott
                  to perform its obligations under this Agreement, including,
                  but not limited to, its Co-Promotion activities, and only if
                  the recipient of such information is under a duty of
                  confidentiality to Abbott.

         9.2      RESTRICTION. Each party shall restrict dissemination of
                  Confidential Information to those of its employees,
                  contractors, agents and sublicensees (if any) who have an
                  actual need to know and have a legal obligation to protect the
                  confidentiality of such Confidential Information. All
                  Confidential Information disclosed by one

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                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                  party to the other shall remain the sole property of the
                  disclosing party and neither party shall obtain any right of
                  any kind to the Confidential Information disclosed, except as
                  granted under this Agreement.

         9.3      RESTRICTION EXEMPTIONS. Nothing contained in this Article 9
                  shall be construed to restrict the parties from using or
                  disclosing Confidential Information solely to the extent and
                  solely as required:

                  (a)      for regulatory, tax or customs reasons;

                  (b)      by court order or other governmental order or written
                           request, provided in each case the party disclosing
                           information promptly informs the other and uses its
                           best efforts to limit the disclosure and to maintain
                           confidentiality to the maximum extent possible and
                           permits the other party to attempt by appropriate
                           legal means to limit such disclosure; or

                  (c)      to perform acts permitted by this Agreement,
                           including (i) disclosure by Myogen to third parties
                           undertaking feasibility and evaluation studies,
                           clinical trials and the like on behalf of Myogen, so
                           long as such third parties are under a legal
                           obligation to Myogen to protect the confidentiality
                           of such Confidential Information, or (ii) disclosure
                           by Myogen to sublicensees, so long as such
                           sublicensees are under a legal obligation to Myogen
                           to protect the confidentiality of such Confidential
                           Information, or (iii) disclosure by Myogen in
                           connection with the marketing and commercial sale of
                           Product, or (iv) disclosure by Myogen to the extent
                           required by law; and (v) disclosure by Abbott in
                           connection with its Co-Promotion activities, if any.

10.      TERM AND TERMINATION

         10.1     This Agreement shall continue in effect unless and until
                  terminated as provided in this Section 10 or in Section
                  6.3(b). Upon the end of the Royalty Period in any country of
                  the Myogen Territory, Myogen shall have an exclusive, subject
                  to Abbott's Co-Promotion Rights, perpetual and irrevocable
                  license under the Abbott Technology, with all of the rights
                  granted under Article 2 hereof, and without any further
                  obligation to Abbott, except for the payment obligations
                  accruing prior to such date and the indemnification
                  obligations under Section 8.3, and except for any obligation
                  to pay a reduced royalty for the Reduced Royalty Period, as
                  provided in Section 7.4(b) hereof.

         10.2     If, after January 1, 2004, Myogen determines in its reasonable
                  scientific and commercial judgment that the Compound does not
                  have an acceptable profile or a reasonable likelihood of
                  commercial success, or that it is economically or technically
                  impractical for Myogen to continue developing and marketing
                  the Product, Myogen shall have the right to terminate this
                  Agreement upon ninety

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED      22
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                  (90) days written notice, at the end of which the termination
                  shall be effective. Upon such termination, Myogen shall pay
                  all payments and royalties which may have become due prior to
                  the effective date of such termination, including, but not
                  limited to, the Second License Fee Payment provided for under
                  Section 7.2, and Myogen shall assign and deliver, and Abbott
                  shall be entitled to retain for its own use, all studies and
                  information relating to the Compound. Myogen shall transfer
                  all RA's held in its name and Abbott shall be granted a
                  license to all Improvements as set forth in Section 15 hereof.
                  In addition, Myogen shall continue to be responsible for any
                  milestones obtained by Myogen (or its sublicensee) with
                  respect to the Product thereafter notwithstanding Myogen's
                  earlier termination under this Section 10.2.

         10.3     Either party may terminate this Agreement by giving to the
                  other party prior written notice of not less than thirty (30)
                  days in the case of a monetary breach and of not less than
                  ninety (90) days in the event the other party shall commit a
                  non-monetary material breach of this Agreement (other than an
                  alleged breaches of Sections 6.3(a) or 6.5(b) or Section
                  6.4(a), in which event the provisions of Sections 6.3(b) and
                  Section 6.4(b), respectively, shall apply), and such breaching
                  party (or that party's sublicensee) shall fail to cure, or
                  commence action to cure, such breach during such thirty (30)
                  or ninety (90) day period, as applicable. In the case of a
                  non-monetary breach (other than an alleged breaches of
                  Sections 6.3(a) or 6.5(b) or Section 6.4(a), the cure period
                  may be extended for such longer period as may reasonably be
                  necessary if cure is not reasonably possible within the
                  initial ninety (90) day period, provided the breaching party
                  continues its diligent efforts to cure. No such cancellation
                  and termination shall release the breaching party from any
                  obligations hereunder incurred prior thereto. In the event of
                  a dispute whether a material breach has occurred, the
                  existence of material breach shall be determined using the ADR
                  procedure set forth in Exhibit D. A party's right to terminate
                  this Agreement shall only apply if the breaching party fails
                  to cure such breach in the manner required by the final
                  judgment of the ADR hearing. In the event that this Agreement
                  is terminated for Myogen's material breach, Abbott shall be
                  entitled to retain for its own use all funds previously paid
                  by Myogen, Myogen shall pay all payments and royalties which
                  may have become due prior to the effective date of such
                  termination, including, but not limited to, the Second License
                  Fee Payment provided for under Section 7.2, and Myogen shall
                  assign and deliver, and Abbott shall be entitled to retain for
                  its own use, all studies and information relating to the
                  Compound, Myogen shall transfer all RA's held in its name and
                  Abbott shall be granted a license to all Improvements
                  generated hereunder as set forth in Section 15 hereof. In the
                  event this Agreement is terminated for Abbott's material
                  breach, Myogen shall be entitled to retain for its own use all
                  studies, information and Improvements generated hereunder, no
                  license to Improvements shall be granted to Abbott under
                  Section 15 hereof and Abbott shall be obligated pay any
                  amounts that became payable pursuant to this Agreement prior
                  to the termination date.

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED      23
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

         10.4     Either party may terminate this Agreement on thirty (30) days
                  notice if the other party passes a resolution or the court
                  makes an order for its winding up; or has a receiver or
                  administrator appointed over its business or all of its
                  assets; or is or becomes bankrupt; or ceases its business
                  operations. In the event that this Agreement is terminated
                  under this Section 10.4, subject to the other terms of this
                  Agreement, the terminating party shall be entitled to the
                  assignment and delivery of, and shall be entitled to retain
                  for its own use all studies, information and Improvements
                  (subject to the license set forth in Section 15 as it concerns
                  Abbott) generated hereunder. Notwithstanding the bankruptcy or
                  insolvency of Abbott or the impairment of performance by
                  Abbott of its obligations under this Agreement as a result of
                  bankruptcy or insolvency of Abbott, Myogen shall be entitled
                  to retain the licenses granted herein, without any further
                  obligation to Abbott other than the payment obligations under
                  Article 7.

         10.5     Termination of this Agreement shall be without prejudice to
                  any rights of either party against the other which may have
                  accrued up to the date such termination becomes effective.

         10.6     All causes of action accruing to either party under this
                  Agreement shall survive expiration or termination of this
                  Agreement for any reason.

         10.7     Upon any termination or expiration of this Agreement, each
                  party shall promptly return to the other party all written
                  Confidential Information of the other party, and all copies
                  thereof (retaining one copy of the Confidential Information of
                  the other in its confidential files for archival purposes
                  only), which is not covered by a paid-up license or other
                  rights specified herein surviving such termination or
                  expiration.

         10.8     In the event the Myogen license in Article 2 hereof is
                  terminated for any country due to an uncured material breach
                  by Myogen, Myogen agrees to provide Product to Abbott and/or
                  its Affiliates, or their designee, for sale in each such
                  country at the same fully burdened delivered cost of goods (as
                  evidenced by Myogen's internal records) incurred by Myogen in
                  procuring or manufacturing Product for its own sales and to
                  cooperate with Abbott, or its designee, by, among other
                  things, coordinating marketing and sales strategies consistent
                  with Myogen's global Product marketing strategies, clinical
                  studies and development plans.

11.      INFRINGEMENT OF PATENTS BY THIRD PARTY. In the event of an actual or
         suspected infringement of a Patent by a Third Party, the following
         shall apply:

         11.1     NOTICE. Each party shall give the other written notice if one
                  of them becomes aware of any infringement by a Third Party of
                  any Patent. Upon notice of any such infringement, the parties
                  shall promptly consult with one another with a view toward
                  reaching agreement on a course of action to be pursued.

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED      24
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

         11.2     ABBOTT'S RIGHT TO BRING INFRINGEMENT ACTION.

                  (a)      ABBOTT ELECTION. If a Third Party infringes any
                           Patent, Abbott shall have the right, but not the
                           obligation, to institute and prosecute an action or
                           proceeding to abate such infringement and to resolve
                           such matter by settlement or otherwise.

                           (i)      Abbott shall notify Myogen of its intention
                                    to bring an action or proceeding prior to
                                    filing the same and in sufficient time to
                                    allow Myogen the opportunity to discuss with
                                    Abbott the choice of counsel for such
                                    matter. Abbott shall keep Myogen informed of
                                    material developments in the prosecution or
                                    settlement of such action or proceeding.
                                    Abbott shall be responsible for all fees and
                                    expenses of any action or proceeding against
                                    infringes which Abbott initiates. Myogen
                                    shall cooperate fully [/\#/\], including
                                    executing and making available such
                                    documents as Abbott may reasonably request,
                                    and Myogen may, at its option or at the
                                    request of Abbott, join such action as
                                    co-plaintiff or party plaintiff if legally
                                    permissible or if the maintenance of the
                                    action or proceeding requires the same. In
                                    the event Myogen joins such action or
                                    proceeding at its election, or at the
                                    request of Abbott, it may be represented by
                                    its own counsel [/\#/\].

                           (ii)     If Abbott elects not to exercise such right,
                                    and the parties disagree on the utility of
                                    bringing an action against an alleged
                                    infringer, then the parties shall submit
                                    their disagreement to a mutually agreeable
                                    Third Party attorney with experience in
                                    patent litigation in the country of
                                    infringement for resolution. If the Third
                                    Party attorney decides that an infringement
                                    action has a reasonable chance of success,
                                    then Abbott shall be obligated to institute
                                    an action or proceeding in accordance with
                                    Section 11.2(a)(i) above. If the Third Party
                                    attorney decides that an infringement action
                                    does not have a reasonable chance of
                                    success, then no action shall be brought by
                                    either party unless Abbott elects within ten
                                    (10) days of the neutral's decision to
                                    institute such an action or proceeding (or
                                    except as otherwise provided in accordance
                                    with Section 11.2(a)(iii) below).

                           (iii)    If Myogen reasonably believes there is
                                    substantial merit to bringing such an action
                                    notwithstanding the neutral's decision
                                    pursuant to Section 11.2(a)(ii) above; or if
                                    Abbott elects to bring such action but
                                    delegates the authority to institute and
                                    prosecute such action or proceeding to
                                    Myogen, Myogen shall have the right to
                                    institute and prosecute such action or
                                    proceeding to abate such

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     25
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                                    infringement and to resolve such matter by
                                    settlement or otherwise. Abbott shall
                                    cooperate fully by joining as a party
                                    plaintiff if reasonably requested to do so
                                    by Myogen or if required to do so by law to
                                    maintain such action and by executing and
                                    making available such documents as Myogen
                                    may reasonably request. Abbott may be
                                    represented by counsel in any such action,
                                    [/\#/\].

                           (b)      ABBOTT'S USE OF PROCEEDS. All amounts of
                                    every kind and nature recovered from an
                                    action or proceeding of infringement brought
                                    by Abbott shall belong to Abbott, and shall
                                    be used first to reimburse Abbott for its
                                    documented and actual costs of prosecution,
                                    including attorneys' fees, expert fees and
                                    all other related expenses, second to
                                    reimburse Myogen for its documented and
                                    actual costs if it is represented by counsel
                                    in the proceeding. If such damage award is
                                    based upon a finding of Myogen's lost sales,
                                    the balance of the amount awarded as
                                    compensatory damages shall, beyond the costs
                                    incurred by Abbott and Myogen for their
                                    respective participations in the action or
                                    proceeding, shall first be used to provide
                                    Abbott the royalty it would have received if
                                    the lost sales had been licensed sales of
                                    Myogen under Section 7.4(a) hereinabove, and
                                    then the parties shall [/\#/\] unless the
                                    award is based upon lost profits of Myogen
                                    and Myogen participated as a party. In such
                                    case, Myogen shall be entitled to [/\#/\] of
                                    said remainder. Any exemplary damages
                                    awarded shall be [/\#/\] between Myogen and
                                    Abbott; [/\#/\].

                           (c)      MYOGEN'S USE OF PROCEEDS. All amounts of
                                    every kind and nature recovered from an
                                    action or proceeding of infringement brought
                                    by Myogen [/\#/\], and shall first be used
                                    to reimburse Myogen for its documented and
                                    actual costs of prosecution, second to
                                    reimburse Abbott for its documented and
                                    actual costs if it is represented by counsel
                                    in the proceedings, and the balance shall be
                                    considered Net Sales under this Agreement
                                    and subject to royalty obligation under
                                    Section 7.4.

12.      INFRINGEMENT OF THIRD PARTY RIGHTS; MYOGEN DEFENSE OF SUIT. If Abbott,
         its Affiliates, Myogen, its Affiliates, sublicensees, distributors or
         other customers are sued or threatened with suit by a Third Party
         alleging infringement of patents or other intellectual property rights
         that are alleged to cover the manufacture, use, sale, import, export or
         distribution of one or more Products, Abbott or Myogen, whichever is
         relevant, will promptly notify the other in writing and provide a copy
         of the lawsuit or claim. Myogen shall control the defense in any such
         claim or suit. Myogen shall keep Abbott timely informed of material
         developments in the defense of such claim or suit. If Myogen expends
         any amounts in connection with any Third Party claim of infringement or
         misappropriation, or is required to pay a royalty or other amount to a
         Third Party for the manufacture, use, sale, import, export or
         distribution of one or more Products in the Myogen Territory as a
         result of a final judgment or settlement, such amounts shall be

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     26
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

         [/\#/\], but only where such claim, judgment or settlement arises out
         of Myogen's practice of a Patent or use of the Abbott Technology
         pursuant to the license granted under Article 2 of this Agreement
         except where such claim, judgment or settlement alleges an infringement
         arising from the practice of a Patent or use of the Abbott Technology
         in combination with the technology of a Third Party and such
         infringement would have been avoided without such combination. Abbott
         shall fully cooperate with Myogen in the defense of any such action at
         Abbott's expense. Myogen shall have the right to settle any such suit,
         including the right to grant one or more sublicenses with Abbott's
         prior written approval, which approval shall not unreasonably be
         withheld, provided that Myogen shall not otherwise have the right to
         surrender, limit or adversely affect any rights to the Patents. The
         terms of this Article 12 shall not apply to or affect Abbott's
         indemnity obligation for a breach of Section 8.1(c).

13.      PATENT PROSECUTION AND MAINTENANCE; PATENT COSTS: PATENT TERM
         EXTENSION.

         13.1     DISCLOSURE OF PATENTS/APPLICATIONS TO MYOGEN. Within thirty
                  (30) days of Myogen's request, Abbott shall provide Myogen a
                  list of Patents and patent applications in a given Patent
                  family. If, following Myogen's receipt of such list(s), Myogen
                  requests additional information, Abbott shall provide to
                  Myogen the complete text of, and all other information in its
                  possession or control directly related to (a) all patent
                  applications included in the given Patent family filed
                  anywhere in the Territories, and (b) all patents included in
                  the given Patent family as well as all information in
                  Abbott's, its Affiliates and its patent counsel's possession
                  concerning the institution or possible institution of any
                  interference, opposition, reexamination, reissue, revocation,
                  nullification or any official proceeding involving an issued
                  patent included in the given Patent family a[nywhere in the
                  Myogen Territory.

         13.2     PROSECUTION AND MAINTENANCE. Abbott shall be solely
                  responsible for the preparation, filing, prosecution and the
                  associated costs incurred in connection with maintenance of
                  the Patents (except for the case family including [/\#/\]
                  which is the responsibility of BASF AG; provided always that
                  Abbott shall use Commercially Reasonable Efforts to cause BASF
                  AG to defend or prosecute the case family as necessary) in
                  Abbott's name, including oppositions and interferences,
                  subject to Myogen's right to assume such duties in the event
                  Abbott reasonably fails to adequately prepare, file, prosecute
                  and maintain the Patents. By June 30, 2003, Abbott shall
                  inform BASF AG of Abbott's desire to have the Patent family
                  for which BASF AG has responsibility transferred to Abbott and
                  Abbott shall use commercially reasonable efforts to have BASF
                  AG agree to such transfer to Abbott within a reasonable time
                  after the Effective Date, and upon such transfer such Patents
                  will be subject to the same terms and conditions of this
                  Agreement as the Patents for which Abbott has responsibility
                  as of the Effective Date. Abbott and Myogen shall consult and
                  cooperate with each other, and Abbott shall keep Myogen
                  reasonably informed with respect to the prosecution

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED      27
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                  and maintenance of the Patents hereunder, including the case
                  family which is the responsibility of BASF AG. In this regard
                  Abbott shall exercise its rights under its license from BASF
                  AG for this Patent family such that Myogen shall have the
                  opportunity to participate in the preservation of these Patent
                  rights if it chooses to do so. In connection with its duties
                  under this Section 13.2, Abbott will provide Myogen with: (a)
                  copies of all material documents received or prepared by
                  Abbott in the prosecution and maintenance of the Patents; (b)
                  advance written notice to the extent reasonably practical of
                  any action or proceeding relating to any Patent; and (c) a
                  bi-annual report on the status of prosecution of all Patents.
                  Abbott shall provide copies in a timely manner to allow Myogen
                  an opportunity, if it so elects, to review and comment on
                  Abbott's proposed patent strategy. If Myogen determines, upon
                  advice of its patent counsel, that further prosecution actions
                  with respect to an existing application within the Patents or
                  a reexamination, reissue, interference and action under 35 USC
                  Paragraph 146 or other official proceeding involving an issued
                  Patent anywhere in the Myogen Territory is required to ensure
                  the enforceability of such Patent or adequate claim coverage
                  within such Patents, Abbott shall have the right and sole
                  responsibility for conducting such prosecution action or
                  instituting such proceeding. If Abbott elects not to exercise
                  such right, then Myogen shall have the right and sole
                  responsibility for the pursuit of such activities, and Abbott
                  shall cooperate with Myogen and provide Myogen with all
                  necessary information to conduct such activities. Inasmuch as
                  the Patents cover other compounds not licensed to Myogen
                  hereunder, Abbott warrants that it will not take any action
                  with respect to the Patents, which would have a material
                  adverse effect on the patent coverage of the Compound.

         13.3     PATENT EXTENSIONS. Abbott shall have the right and sole
                  responsibility for obtaining patent term extensions under the
                  provisions of 35 USC Paragraph 156 for any U.S. Patent and for
                  non-U.S. Patents under similar provisions of law of other
                  countries involving a Product which has obtained Regulatory
                  Approval. Myogen shall cooperate with Abbott and provide
                  Abbott with all necessary information to obtain such
                  extensions. If Abbott elects not to exercise such right,
                  Myogen may file for such extension at its own expense, and
                  Abbott shall cooperate with Myogen and provide Myogen with all
                  necessary information to obtain such extensions.

14.      TRADEMARK. Myogen may select any Trademark or Trademarks for the
         Product in the Myogen Territory including the Co-Promotion Territory,
         ("MYOGEN TRADEMARKS"). All costs related to the selection and
         maintenance of the Myogen Trademark(s) shall be borne by Myogen. The
         Myogen Trademark(s) shall be owned by Myogen, and Abbott shall have no
         claims or rights in or to the Myogen Trademark(s), except such right as
         may be necessary for Abbott to commercialize Product following a
         termination under Sections 10.2, 10.3 or 10.4 above, and/or to fulfill
         its Co-Promotion activities in the Co-Promotion Territory.

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED      28
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

15.      IMPROVEMENTS. All Improvements made solely by Myogen and/or its
         Affiliates hereunder shall be the sole and exclusive property of Myogen
         ("MYOGEN IMPROVEMENTS"). All Improvements made solely by Abbott and/or
         its Affiliates ("ABBOTT IMPROVEMENTS") shall become part of the Abbott
         Technology, subject to the license to Myogen set forth in Article 2
         hereof. All Improvements made jointly by employees or others acting on
         behalf of Abbott and Myogen (or their Affiliates) hereunder shall be
         jointly owned by Abbott and Myogen ("JOINT IMPROVEMENTS"), without a
         duty of accounting to the other, to the extent such individuals would
         be considered "joint inventors" within the meaning of the U.S. patent
         laws. Each party shall take all necessary actions, including executing
         documents of assignment, to vest title to all Joint Improvements
         (including all intellectual property rights therein) with both parties.
         With respect to patents resulting from Joint Improvements, the parties
         shall select a mutually agreeable Third Party attorney to prepare,
         file, prosecute and maintain such patents. The Third Party attorney
         shall consult and apprise each party equally and both parties shall
         share 50/50 the costs and fees of employing such Third Party attorney.
         Abbott's interest in such Joint Improvements shall be subject to the
         license granted to Myogen under Article 2 hereof and subject to the
         terms and conditions of this Agreement. In the event this Agreement is
         terminated by Abbott for any reason, as set forth in Article 10, or by
         Myogen under Section 10.2, all Myogen improvements shall be exclusively
         licensed to Abbott solely for use with the Compound and Product on a
         worldwide basis on terms to be mutually agreed to by the parties after
         good faith negotiations, and Myogen retains all rights in and to any
         Myogen Improvements for any and all other uses.

16.      MISCELLANEOUS.

         16.1     FORCE MAJEURE. If the performance by either party of any of
                  its obligations under this Agreement shall be prevented by
                  circumstances beyond its reasonable control, which could not
                  have been avoided by the exercise of reasonable diligence,
                  then such party shall be excused from the performance of that
                  obligation for the duration of the event. The affected party
                  shall promptly notify the other party in writing should such
                  circumstances arise, give an indication of the likely extent
                  and duration thereof, and shall use commercially reasonable
                  efforts to resume performance of its obligations as soon as
                  practicable.

         16.2     NOTICES. Any notice required to be given or made under this
                  Agreement by one of the parties hereto to the other shall be
                  in writing, by personal delivery, registered U.S. mail or
                  overnight courier, addressed to such other party at its
                  address indicated below, or to such other address as the
                  addressee shall have last furnished in writing to the
                  addressor and shall be effective upon the date of receipt.

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     29
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                  If to Myogen:         Myogen, Inc.
                                        7575 W. 103rd Avenue, #102
                                        Westminster, CO 80021-5426
                                        Attn:  President

                  With a copy to:       Cooley Godward LLP
                                        380 Interlocken Crescent
                                        Suite 900
                                        Broomfield, CO  80021-8023
                                        Attn:  Steven N. Dupont, Esq.

                  If to Abbott:         Abbott International Ltd.
                                        100 Abbott Park Road
                                        Dept. 6WP; Bldg. AP34
                                        Abbott Park, IL  60064-3537
                                        Attn:  Senior Vice President,
                                        International Operations

                  With a copy to:       Abbott Laboratories
                                        100 Abbott Park Road
                                        Dept. 364; Bldg. AP6D
                                        Abbott Park, IL 60064-6032
                                        Attn:  Senior Vice President, Secretary
                                        and General Counsel

         16.3     APPLICABLE LAW/COMPLIANCE. This Agreement shall be governed by
                  and construed in accordance with the laws of the State of
                  Illinois, excluding its conflict of laws provision. Each party
                  hereto shall comply with all applicable laws, rules,
                  ordinances, guidelines, consent decrees and regulations of any
                  federal, state or other governmental authority.

         16.4     ENTIRE AGREEMENT. This Agreement and the attachments
                  (Exhibits) contain the entire understanding of the parties
                  with respect to the subject matter hereof. All express or
                  implied agreements and understandings, either oral or written,
                  heretofore made are expressly merged in and made a part of
                  this Agreement. This Agreement may be amended, or any term
                  hereof modified, only by a written instrument duly executed by
                  both parties hereto.

         16.5     COUNTERPARTS . This Agreement may be executed in two or more
                  counterparts, each of which shall be deemed an original, but
                  all of which together shall constitute one and the same
                  instrument.

         16.6     SEVERABILITY/HEADINGS. If any provision of this Agreement is
                  deemed unenforceable, the remainder of the Agreement will not
                  be affected and, if

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                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                  appropriate, the parties will attempt to replace the
                  unenforceable provision with a new provision that, to the
                  extent possible, reflects the parties' original intent. The
                  captions and headings used in this Agreement are for reference
                  only and are not to be construed in any way as terms or used
                  to interpret the provisions of this Agreement.

         16.7     ASSIGNMENT. Neither party may without written approval of the
                  other assign this Agreement or transfer its interest or any
                  part thereof under this Agreement to any Third Party except
                  that (a) either party may assign this Agreement without
                  consent to a Third Party that acquires all or substantially
                  all of the business to which this Agreement pertains, or, (b)
                  either party may assign this Agreement in whole or part to any
                  Affiliate of that party and such party hereby guarantees the
                  performance by such Affiliate.

         16.8     DISPUTE RESOLUTION. The parties hereto shall attempt to settle
                  any dispute arising out of or relating to this Agreement in an
                  amicable way. Except for claims for injunctive or other
                  equitable relief, which may be brought in any court of
                  competent jurisdiction, any controversy, claim or right of
                  termination for cause which may arise under, out of, in
                  connection with, or relating to this Agreement, or any breach
                  thereof, shall be settled according to the Alternative Dispute
                  Resolution provisions attached hereto as Exhibit D.

         16.9     INDEPENDENT CONTRACTOR. It is understood that both parties
                  hereto are independent contractors and engage in the operation
                  of their own respective businesses and neither party hereto is
                  to be considered the agent of the other party for any purpose
                  whatsoever and neither party has any authority to enter into
                  any contract or assume any obligation for the other party or
                  to make any warranty or representation on behalf of the other
                  party. Each party shall be fully responsible for its own
                  employees, servants and agents, and the employees, servants
                  and agents of one party shall not be deemed to be employees,
                  servants and agents of the other party for any purpose
                  whatsoever.

         16.10    SURVIVAL. Sections 8.1, 8.2, 8.3, 8.4 and 8.6, Articles 9, of
                  this Agreement shall survive the expiration or termination of
                  this Agreement for any reason for a period of seven (7) years,
                  Articles 15, 16.8 and 16.10 of this Agreement shall survive
                  the expiration or termination of this Agreement for any reason
                  and Article 7 shall survive early termination of this
                  Agreement for any reason with respect to Product sold prior to
                  such termination and with respect to Product sold after such
                  termination if such termination was by Myogen pursuant to
                  Section 10.2, by Abbott for Myogen's breach pursuant to
                  Section 10.3, or by Abbott by reason of Myogen's insolvency
                  under Section 10.4. Nothing contained in the preceding
                  sentence shall be deemed to entitle Abbott to double recovery
                  of damages under any patent infringement suit against Myogen.

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     31
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

         16.11    PUBLICITY. No press release or other public announcement shall
                  be made by either party concerning the execution of this
                  Agreement or the fact that Myogen has licensed the Compound
                  from Abbott, without the prior written consent of the
                  non-disclosing party, which consent shall not be unreasonably
                  withheld. Neither party shall use the name of the other party,
                  its officers, employees or agents for purposes of any public
                  commercial activity without the other party's prior written
                  consent, except where the name of the other party must be
                  disclosed as a matter of law. Should either party wish to make
                  a disclosure or be required by law to make a disclosure, the
                  disclosing party shall submit a copy of the proposed
                  disclosure to the other party for review. The non-disclosing
                  party shall have two (2) weeks to review and comment on the
                  content of such disclosure. In the case of a disclosure
                  required by law, the disclosing party, subject to legal
                  requirements, shall use all reasonable efforts to accommodate
                  the non-disclosing party's comments. For non-routine matters
                  like an emergency, special circumstance, or other situation
                  where the law compels a disclosure in less than three (3)
                  week's time, the non-disclosing party agrees to use
                  commercially reasonable efforts to provide its review and
                  comment in order to meet the disclosing party's timetable.

                  (REMAINDER OF PAGE INTENTIONALLY LEFT BLANK)

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     32
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the Effective Date.

ABBOTT LABORATORIES                        MYOGEN, INC.

By: /s/ Jeffrey M. Leiden                  By:  /s/ J. William Freytag
    -----------------------------------         --------------------------------

Name: Jeffrey M. Leiden                    Name: J. William Freytag
      ---------------------------------          -------------------------------

Its: President & COO                       Its:  President & CEO
     ----------------------------------          -------------------------------

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     1
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                                    EXHIBIT A

                                       TO
                           EXCLUSIVE LICENSE AGREEMENT
                                     BETWEEN
                               ABBOTT LABORATORIES
                                       AND
                                  MYOGEN, INC.
                               DATED JUNE 30, 2003

                                 PATENTS [/\#/\]

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED

<Table>
<Caption>
  NO.         PRIORITY DATE      WO NUMBER      IN-HOUSE NO.       TITLE
-------       -------------      ---------      ------------      -------
<S>           <C>                <C>            <C>               <C>

[/\#/\]          [/\#/\]          [/\#/\]          [/\#/\]        [/\#/\]
[/\#/\]          [/\#/\]          [/\#/\]          [/\#/\]        [/\#/\]
[/\#/\]          [/\#/\]          [/\#/\]          [/\#/\]        [/\#/\]
[/\#/\]          [/\#/\]          [/\#/\]          [/\#/\]        [/\#/\]
[/\#/\]          [/\#/\]          [/\#/\]          [/\#/\]        [/\#/\]
[/\#/\]          [/\#/\]          [/\#/\]          [/\#/\]        [/\#/\]
[/\#/\]          [/\#/\]          [/\#/\]          [/\#/\]        [/\#/\]
[/\#/\]          [/\#/\]          [/\#/\]          [/\#/\]        [/\#/\]
[/\#/\]          [/\#/\]          [/\#/\]          [/\#/\]        [/\#/\]
[/\#/\]          [/\#/\]          [/\#/\]          [/\#/\]        [/\#/\]
</Table>

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     1

<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                                    EXHIBIT B

                                       TO
                           EXCLUSIVE LICENSE AGREEMENT
                                     BETWEEN
                               ABBOTT LABORATORIES
                                       AND
                                  MYOGEN, INC.
                               DATED JUNE 30, 2003

                                    WORK PLAN
                                  (PRELIMINARY)

[/\#/\]

                        PRELIMINARY DEVELOPMENT TIMELINES

[DRAWING]

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     1

<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                                    EXHIBIT C

                                       TO
                           EXCLUSIVE LICENSE AGREEMENT
                                     BETWEEN
                               ABBOTT LABORATORIES
                                       AND
                                  MYOGEN, INC.
                               DATED JUNE 30, 2003

                              PRE-CLINICAL STUDIES

[/\#/\]

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     1

<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                                    EXHIBIT D

                                       TO
                           EXCLUSIVE LICENSE AGREEMENT
                                     BETWEEN
                               ABBOTT LABORATORIES
                                       AND
                                  MYOGEN, INC.
                               DATED JUNE 30, 2003

                         ALTERNATIVE DISPUTE RESOLUTION

         The parties recognize that from time to time a dispute may arise
relating to either party's right or obligations under this Agreement. The
parties agree that any such dispute shall be resolved by the Alternative Dispute
Resolution ("ADR") provisions set forth in this Exhibit, the result of which
shall be binding upon the parties.

         To begin the ADR process, a party first must send written notice of the
dispute to the other party for attempted resolution by good faith negotiations
between their respective presidents (or their designees) of the affected
subsidiaries, divisions, or business units within twenty-eight (28) days after
such notice is received (all references to "days" in this ADR provision are to
calendar days). If the matter has not been resolved within twenty-eight (28)
days of the notice of dispute, or if the parties fail to meet within such
twenty-eight (28) days, either party may initiate an ADR proceeding as provided
herein. The parties shall have the right to be represented by counsel in such a
proceeding.

1.       To begin an ADR proceeding, a party shall provide written notice to the
         other party of the issues to be resolved by ADR. Within fourteen (14)
         days after its receipt of such notice, the other party may, by written
         notice to the party initiating the ADR, add additional issues to be
         resolved within the same ADR.

2.       Within twenty-one (21) days following receipt of the original ADR
         notice, the parties shall select a mutually acceptable neutral to
         preside in the resolution of any disputes in this ADR proceeding. If
         the parties are unable to agree on a mutually acceptable neutral within
         such period, either party may request the President of the CPR
         Institute for Dispute Resolution ("CPR"), 366 Madison Avenue, 14th
         Floor, New York, New York 10017, to select a neutral pursuant to the
         following procedures:

         (a)      The CPR shall submit to the parties a list of not less than
                  five (5) candidates within fourteen (14) days after receipt of
                  the request, along with a Curriculum Vitae for each candidate.
                  No candidate shall be an employee, director, or shareholder of
                  either party or any of their subsidiaries or affiliates.

         (b)      Such list shall include a statement of disclosure by each
                  candidate of any circumstances likely to affect his or her
                  impartiality.

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED    1

<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

         (c)      Each party shall number the candidates in order of preference
                  (with the number one (1) signifying the greatest preference)
                  and shall deliver the list to the CPR within seven (7) days
                  following receipt of the list of candidates. If a party
                  believes a conflict of interest exists regarding any of the
                  candidates, that party shall provide a written explanation of
                  the conflict to the CPR along with its list showing its order
                  of preference for the candidates. Any party failing to return
                  a list of preferences on time shall be deemed to have no order
                  of preference.

         (d)      If the parties collectively have identified fewer than three
                  (3) candidates deemed to have conflicts, the CPR immediately
                  shall designate as the neutral the candidate for whom the
                  parties collectively have indicated the greatest preference.
                  If a tie should result between two candidates, the CPR may
                  designate either candidate. If the parties collectively have
                  identified three (3) or more candidates deemed to have
                  conflicts, the CPR shall review the explanations regarding
                  conflicts and, in its sole discretion, may either (i)
                  immediately designate as the neutral the candidate for whom
                  the parties collectively have indicated the greatest
                  preference, or (ii) issue a new list of not less than five (5)
                  candidates, in which case the procedures set forth in
                  subparagraphs 2(a) -2(d) shall be repeated.

3.       The ADR proceeding will be governed by and subject to the principles
         specified in the "CPR Rules for Non-Administered Arbitration" except to
         the extent such rules conflict with any of the provisions of this
         Agreement. No earlier than twenty-eight (28) days or later than six (6)
         months after selection, the neutral shall hold a hearing to resolve
         each of the issues identified by the parties, provided that the parties
         agree that stated goal of the parties is to hold such hearing within
         fifty-six (56) days after selection. The ADR proceeding shall take
         place at a location agreed upon by the parties. If the parties cannot
         agree, the neutral shall designate a location other than the principal
         place of business of either party or any of their subsidiaries or
         affiliates.

4.       At least seven (7) days prior to the hearing, each party shall submit
         the following to the other party and the neutral:

         (a)      a copy of all exhibits on which such party intends to rely in
                  any oral or written presentations to the neutral;

         (b)      a list of any witnesses such party intends to call at the
                  hearing, and a short summary of the anticipated testimony of
                  each witness;

         (c)      a proposed ruling on each issue to be resolved, together with
                  a request for a specific damage aware or other remedy for each
                  issue. The proposed rulings and remedies shall not contain any
                  recitation of the facts or any legal arguments and shall not
                  exceed one (1) page per issue.

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     2

<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

         (d)      a brief in support of such party's proposed rulings and
                  remedies, provided that the brief shall not exceed twenty (20)
                  pages. This page limitation shall apply regardless of the
                  number of issues raised in the ADR proceeding.

         Except as expressly set forth in subparagraphs 4(a) - 4(d), no
         discovery shall be required or permitted by any means, including
         depositions, interrogatories, requests for admissions, or production of
         documents.

5.       The hearing shall be conducted on two (2) consecutive days and shall be
         governed by the following rules:

         (a)      Each party shall be entitled to five (5) hours of hearing time
                  to present its case. The neutral shall determine whether each
                  party has had the five (5) hours to which it is entitled.

         (b)      Each party shall be entitled, but not required, to make an
                  opening statement, to present regular and rebuttal testimony,
                  documents or other evidence, to cross-examine witnesses, and
                  to make a closing argument. Cross-examination of witnesses
                  shall occur immediately after their direct testimony, and
                  cross-examination time shall be charged against the party
                  conducting the cross-examination.

         (c)      The party initiating the ADR shall begin the hearing and, if
                  it chooses to make an opening statement, shall address not
                  only issues it raised but also any issues raised by the
                  responding party. The responding party, if it chooses to make
                  an opening statement, also shall address all issues raised in
                  the ADR. Thereafter, the presentation of regular and rebuttal
                  testimony and documents, other evidence, and closing arguments
                  shall proceed in the same sequence.

         (d)      Except when testifying, witnesses shall be excluded from the
                  hearing until closing arguments.

         (e)      Settlement negotiations, including any statements made
                  therein, shall not be admissible under any circumstances.
                  Affidavits prepared for purposes of the ADR hearing also shall
                  not be admissible. As to all other matters, the neutral shall
                  have sole discretion regarding the admissibility of any
                  evidence.

6.       Within seven (7) days following completion of the hearing, each party
         may submit to the other party and the neutral a post-hearing brief in
         support of its proposed rulings and remedies, provided that such brief
         shall not contain or discuss any new evidence and shall not exceed ten
         (10) pages. This page limitation shall apply regardless of the number
         of issues raised in the ADR proceeding.

7.       The neutral shall rule on each disputed issue within fourteen (14) days
         following completion of the hearing. Such ruling shall adopt in its
         entirety the proposed ruling and remedy of one of the parties on each
         disputed issue but may adopt one party's proposed rulings and remedies
         on some issues and the other party's proposed rulings and remedies on
         other issues. The neutral shall not issue any written opinion or
         otherwise explain the basis of the ruling.

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     3
<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

8.       The neutral shall be paid a reasonable fee plus expenses. These fees
         and expenses, along with the reasonable legal fees and expenses of the
         prevailing party (including all expert witness fees and expenses), the
         fees and expenses of a court reporter, and any expenses for a hearing
         room, shall be paid as follows:

         (a)      If the neutral rules in favor of one party on all disputed
                  issues in the ADR, the losing party shall pay 100% of such
                  fees and expenses.

         (b)      If the neutral rules in favor of one, party on some issues and
                  the other party on other issues, the neutral shall issue with
                  the rulings a written determination as to how such fees and
                  expenses shall be allocated between the parties. The neutral
                  shall allocate fees and expenses in a way that bears a
                  reasonable relationship to the outcome of the ADR, with the
                  party prevailing on more issues, or on issues of greater value
                  or gravity, recovering a relatively larger share of its legal
                  fees and expenses.

9.       The rulings of the neutral and the allocation of fees and expenses
         shall be binding, non-reviewable, and non-appealable, and may be
         entered as a final judgment in any court having jurisdiction.

10.      Except as provided in paragraph 9 or as required by law, the existence
         of the dispute, any settlement negotiations, the ADR hearing, any
         submissions (including exhibits, testimony, proposed rulings, and
         briefs), and the rulings shall be deemed Confidential Information. The
         neutral shall have the authority to impose sanctions for unauthorized
         disclosure of Confidential Information.

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED     4

<PAGE>

                      [/\#/\] CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS
                                 DOCUMENT, MARKED BY BRACKETS, IS FILED WITH THE
                                  SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
                             RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

1  ABBOTT
--------------------------------------------------------------------------------

Global Licensing & New Business Development
Abbott Laboratories
200 Abbott Park Road, Dept R50A/AP34-2
Abbott Park, Illinois 60064

                                                                   June 27, 2003

Myogen, Inc.
7575 W. 103rd Avenue
Westminster, CO 80021-5426

      Re:   License Agreement Dated June 27, 2003 ("License Agreement") Between
            Abbott Laboratories ("Abbott") and Myogen, Inc. ("Myogen")

Dear Sir or Madam:

In the event of a transfer of manufacturing responsibility to a Third Party
Manufacturer for the supply of Compound and/or Product in accordance with
Section 6.6(b) of the License Agreement, Myogen may request the assistance of
Abbott personnel with knowledge and skills in the manufacture of Compound and/or
Product to assist Myogen with such transfer.

Myogen may request such assistance by providing written notice to Abbott
specifying the nature of the assistance requested and suggesting the schedule
for Abbott to provide such assistance. Abbott shall reasonably cooperate with
Myogen's request and assign qualified Abbott personnel to provide such
assistance at a schedule subject to the mutual agreement of the parties.

Myogen shall compensate Abbott for each hour of personnel time spent providing
the assistance at the rate of [/\#/\]. Myogen shall also reimburse Abbott for
all reasonable costs and expenses incurred by such Abbott personnel in
connection with providing the assistance, including reasonable travel and
lodging expenses. The parties agree that Abbott shall not be obligated to supply
more than [/\#/\] of personnel time in response to Myogen's
request.

The parties indicate their agreement to the foregoing understanding by their
signatures below.

ABBOTT LABORATORIES                        MYOGEN, INC.

By: /s/ Signature Illegible                By: /s/J. William Freytag
    ----------------------------------         ---------------------------------
Title: Divisional Vice President           Title: President & CEO
       -------------------------------            ------------------------------
Date: 6-27-03                              Date: 6-27-03
      --------------------------------           -------------------------------

[/\#/\] CONFIDENTIAL TREATMENT REQUESTED    1

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