<PAGE>

                                                                   EXHIBIT 10.37

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

                                LICENSE AGREEMENT

                                    PREAMBLE

     THIS LICENSE AGREEMENT ("Agreement") is entered into as of the 3rd day of
March, 2006 (the "Effective Date") by and between Myogen, Inc., a Delaware
corporation, with its principal place of business at 7575 W. 103rd Avenue,
Westminster, CO 80021-5426 ("Myogen") and GLAXO GROUP LIMITED, a private limited
company incorporated in England and Wales, having its registered office at Glaxo
Wellcome House, Berkeley Avenue, Greenford, Middlesex, England UB6 0NN ("GSK").
Myogen and GSK are sometimes collectively referred to herein as the "Parties"
and separately as a "Party."

     WHEREAS, Myogen is the licensee of certain rights in the Abbott
Intellectual Property (as hereinafter defined), and has the right to grant
certain sublicenses thereunder, relating to Compound (as hereinafter defined)
and/or Product (as hereinafter defined) in the Field (as hereinafter defined);
and

     WHEREAS, GSK desires to obtain an exclusive sublicense from Myogen under
the aforesaid Abbott Intellectual Property to make, have made, use, sell, offer
for sale and import Compound and Product in the Field in the GSK Territory (as
hereinafter defined), and Myogen is willing to grant to GSK such sublicense, in
accordance with the terms and conditions of this Agreement; and

     WHEREAS, Myogen owns or otherwise controls the Myogen Intellectual Property
(as hereinafter defined), and has the right to grant certain licenses
thereunder, relating to Compound and/or Product in the Field; and

     WHEREAS, GSK desires to obtain an exclusive license from Myogen under the
aforesaid Myogen Intellectual Property to make, have made, use, sell, offer for
sale and import Compound and Product in the Field in the GSK Territory, and
Myogen is willing to grant to GSK such license, in accordance with the terms and
conditions of this Agreement.

     NOW, THEREFORE, in consideration of the mutual covenants and agreements set
forth herein and other good and valuable consideration, the receipt and legal
sufficiency of which are hereby mutually acknowledged, Myogen and GSK hereby
agree as follows:

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


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                                    ARTICLE I

                                   DEFINITIONS

     Section 1.1 Definitions. As used herein, the following capitalized terms
will have the meanings set forth below when used in this Agreement, and all
terms defined in the singular will have the same meanings when used in the
plural (and vice versa), unless otherwise specified.

     "Abbott" means Abbott Deutschland Holding GmbH, a German legal entity, with
its principal office at Max Planck Ring 2, 65205 Wiesbaden, Germany.

     "Abbott Agreement" means the License Agreement by and between Abbott and
Myogen, dated as of October 8, 2001, and any amendments thereto. A complete copy
of the Abbott Agreement as of the Effective Date is attached hereto as Exhibit
A.

     "Abbott Intellectual Property" means the Abbott Know-How and Abbott Patent
Rights, collectively.

     "Abbott Know-How" means Know-How that is Controlled by Abbott as of the
effective date of the Abbott Agreement and which has been licensed to Myogen in
accordance with the terms and conditions of the Abbott Agreement.

     "Abbott Patent Rights" means the Patent Rights defined in Section 1.16 of
the Abbott Agreement. Myogen has provided to GSK a list of Abbott Patent Rights
current as of the Effective Date. A list of issued patents and pending PCT
applications included within the Abbott Patent Rights in the GSK Territory is
attached hereto as Exhibit B, and Myogen will update such Exhibit promptly upon
GSK's reasonable written request, which request will not be made by GSK more
than twice in any Calendar Year during the Term.

     An "Affiliate" of a Party or Person means any Person, whether de jure or de
facto, that directly or indirectly, controls, is controlled by, or is under
common control with such Party or Person, as applicable. Solely as used in this
definition, "control" means (a) direct or indirect ownership of more than fifty
percent (50%) of the equity (or such lesser percentage which is the maximum
allowed to be owned by a foreign corporation in a particular jurisdiction)
having the power to vote on or direct the affairs of such Party or Person, as
applicable, or (b) the possession, directly or indirectly, of the power to
direct or cause the direction of the policies and management of such Party or
Person, as applicable, whether by the ownership of stock, by contract, or
otherwise.

     "Agreement" will have the meaning set forth in the preamble.

     "Applicable Law" means all applicable provisions of any and all
supra-national, federal, national, state, provincial, and local statutes, laws,
rules, regulations, administrative codes, ordinances, decrees, orders,
decisions, injunctions, awards judgments, permits and licenses of or from
governmental authorities relating to or governing the use or regulation of the
subject item.

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


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     "Assumption of Responsibility Notice" will have the meaning set forth in
Section 6.1.

     "Auditor" will have the meaning set forth in Section 9.3(e).

     "Business Day" means any day other than a day which is a Saturday, a Sunday
or any day banks are authorized or required to be closed in the United States or
in the United Kingdom.

     "Calendar Quarter" means each of the consecutive three (3) month periods
ending March 31, June 30, September 30, and December 31; provided, however, that
the first (1st) Calendar Quarter under this Agreement will be the period
beginning on the Effective Date and ending on the end of the Calendar Quarter in
which the Effective Date is encompassed.

     "Calendar Year" means, for the first Calendar Year, the period beginning on
the Effective Date and ending December 31, 2006, and for each Calendar Year
thereafter, each successive period beginning on January 1 and ending twelve (12)
consecutive calendar months later on December 31; provided, however, that the
last Calendar Year of the Term will be the period beginning on January 1 and
ending on the effective date of expiration or termination of the Term.

     "Commercially Reasonable Efforts" means efforts and resources normally used
by a similarly situated pharmaceutical company in the GSK Territory or Myogen
Territory, as applicable, in the exercise of its reasonable business discretion
relating to a prescription pharmaceutical product owned by it or to which it has
exclusive rights, which is of similar market potential at a similar stage in its
development or product life, taking into account issues of patent coverage,
safety and efficacy, product profile, the competitiveness of the marketplace,
the proprietary position of the compound or product, the regulatory structure
involved, the profitability of the applicable products (including, without
limitation, pricing and reimbursement status achieved), and other relevant
factors, including without limitation technical, legal, scientific, and/or
medical factors, and provided that all such actions are consistent in all
material respects with the Development Plan or Global Marketing Plan, as the
case may be.

     "Commercialization" or "Commercialize" means activities directed to
obtaining pricing and reimbursement approvals, marketing, promoting,
distributing, using, importing or selling the Product in the Field.
Commercialization will not include any activities related to Development or
Manufacturing.

     "Common Technical Document" means a harmonized structure and format for new
drug product applications developed by ICH to be used by the Parties, as
appropriate and subject to clinical data availability and Applicable Law in a
country, in connection with Regulatory Approval Applications for Product in the
European Union, Japan, Canada and the United States.

     "Compound" will have the meaning set forth in Section 1.5 of the Abbott
Agreement.

     "Confidential Information" means any and all information disclosed to or
obtained by Recipient pursuant to or in connection with the negotiation,
execution, delivery and performance of this Agreement or the consummation of the
transactions contemplated hereby and any and all information regarding, related
to, or associated with any or all elements of this Agreement,

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


                                        2

<PAGE>

including the Development, Manufacture and/or Commercialization of Product in
the Field or any aspect thereof, or each Party's operations that is disclosed by
the Disclosing Party to the Recipient; provided, however, that Confidential
Information will not include information which: (i) at the time of disclosure is
in the public domain; (ii) after disclosure becomes part of the public domain,
except through breach of this Agreement; (iii) the Recipient can demonstrate by
reasonable proof was in its possession prior to the time of disclosure by the
Disclosing Party hereunder, and was not acquired directly or indirectly from the
Disclosing Party; (iv) the Recipient can demonstrate by reasonable proof was
developed by or on behalf of Recipient independent of and without reference to
the Disclosing Party's Confidential Information; or (v) becomes available to
Recipient from a Third Party who did not acquire such information directly or
indirectly from the Disclosing Party and who is not otherwise prohibited from
disclosing such information.

     "Confidentiality Agreement" will have the meaning set forth in Section
13.1(h).

     "Control" means, with respect to the subject item, the ability and
authority of a Party or its Affiliate, whether arising by ownership, possession
or pursuant to a license or sublicense, to grant licenses or sublicenses to the
other Party under or to the subject item as specified in this Agreement, without
breaching the terms of any agreement with any Third Party and/or its Affiliates.

     "Cure Period" will have the meaning set forth in Section 11.2.

     "Development" or "Develop" means non-clinical and clinical research and
drug development activities related to obtaining and maintaining Regulatory
Approval (excluding pricing and reimbursement approvals) for Product in the
Field, including test method development and stability testing, process
development, formulation development, delivery system development, quality
assurance and quality control development for clinical supplies, statistical
analysis, clinical studies (including pre- and post-approval studies),
regulatory affairs, and Regulatory Approval (excluding regulatory activities
directed to obtaining pricing and reimbursement approvals) and clinical study
regulatory activities (excluding regulatory activities directed to obtaining
pricing and reimbursement approvals).

     "Development Information" means any and all information generated by a
Party (or a Party's Affiliates or any Third Party on behalf of a Party (i.e.,
including, without limitation, suppliers of starting materials, excipients and
packaging)) in the Development of Compound and/or Product as provided in this
Agreement, including, without limitation, information relating to chemistry
manufacturing and control (CMC), protocols, analysis plans, annotated case
report forms per study, analysis datasets, programs, raw data and other relevant
documentation used for the study reporting efforts and minutes from clinical
advisory boards and investigator meetings.

     "Development Plan" means the plan for Development of Product in the Field
in the United States, Canada and Major European Market Countries, which will
include, without limitation, the development, operating guidelines and estimated
filing dates, guidelines for filing Regulatory Approval, any preclinical and
clinical studies to be conducted (including, without limitation, [..**..], each
of which the Parties expect to be completed by Myogen according to the

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


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<PAGE>

timelines set forth in the Development Plan.

     "Disclosing Party" will have the meaning set forth in Section 13.1(a).

     "Dispute" will have the meaning set forth in Section 14.1.

     "Dispute Notice" will have the meaning set forth in Section 14.1 hereof.

     "Distributor" means a Third Party engaged by a Party or its Affiliates in a
country in the GSK Territory or Myogen Territory, as applicable, to
Commercialize Compound and/or Product in such country, who is not a Sublicensee
or Wholesaler.

     "Effective Date" will have the meaning set forth in the Preamble.

     "EMEA" means the European Medicines Agency of the European Union, or any
successor agency thereto.

     "European Commission" means the European Community authority that has legal
authority to grant marketing authorizations approvals for pharmaceutical
products on an European Economic Area wide basis following scientific evaluation
and recommendation from the EMEA or other applicable Regulatory Authorities.

     "European Critical Care Business Unit" means the business unit within GSK's
European pharmaceutical business unit that is focused on acute cardiology, the
hospital market and GSK's critical care portfolio in Europe.

     "European Economic Area" means those countries forming part of the European
Economic Area at any time during the Term, including, without limitation, those
countries in the European Union. The term "European Union" as used herein and in
the definition of "EMEA" means the countries forming part of the European Union
at any time during the Term.

     "FDA" means the United States Food and Drug Administration or any successor
agency thereto.

     "Field" means any and all therapeutic uses of Compound and/or Product in
humans for the prevention, palliation or treatment of PAH and related etiologies
as defined by the World Health Organization (WHO) clinical classification of
pulmonary hypertension (Venice 2003), a copy of which is attached hereto as
Exhibit C, but excluding any non-therapeutic or non-human use (which
non-therapeutic or non-human use shall include, but not be limited to, imaging,
diagnostics, veterinary medicine, etc.).

     "First Commercial Sale" means the date of the first commercial sale of a
Product in the Field in a country in the Territory or in the GSK Territory or
Myogen Territory, as applicable, in accordance with the terms of this Agreement,
by a Party and/or its Affiliates or permitted Sublicensees to distributors,
wholesalers or other customers in a quantity sufficient for the distribution of
such Product to pharmacies or other commercial distribution channels for sale in

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


                                       4
<PAGE>

the Field in such country or GSK Territory or Myogen Territory, as applicable.
Sales of Product for compassionate use, named patient use, clinical trial
purposes or other similar uses will not constitute a First Commercial Sale.

     "Force Majeure Event" will have the meaning set forth in Section 15.4(g).

     "Generic Equivalent" means, with respect to a particular Product
Commercialized by GSK, its Affiliates or sublicensees in a given country in the
GSK Territory, a pharmaceutical composition approved by Regulatory Authorities
to be sold by a Third Party in such country, which pharmaceutical composition
contains the Compound as an active ingredient and is bioequivalent to such
Product with respect to pharmacokinetic properties. For the avoidance of doubt,
the Generic Equivalent of a particular Product Commercialized by GSK, its
Affiliates or sublicensees in a given county in the GSK Territory, may or may
not be in the same Presentation as such Product.

     "Global Brand Team" will have the meaning set forth in Section 3.3(a).

     "Global Marketing Plan" means the plan for the pre-launch, launch,
post-launch and ongoing Commercialization activities for the Product in the
Field in the Territory.

     "Good Clinical Practice" means the current good clinical practice
applicable to the clinical Development of the Product in the Field under
Applicable Law, to the extent such standards are not less stringent than the
U.S. current good clinical practice, including the guidelines of the ICH.

     "Good Laboratory Practice" means the current good laboratory practice
applicable to the Development of the Product in the Field under Applicable Law,
to the extent such standards are not less stringent than the U.S. current good
laboratory practice, including 21 C.F.R. Part 58.

     "GSK" will have the meaning set forth in the Preamble.

     "GSK Indemnitees" will have the meaning set forth in Section 14.3.

     "GSK Inventions" will have the meaning set forth in Section 10.2.

     "GSK Know-How" means, solely to the extent necessary or useful for the
purposes of Development, Manufacture and/or Commercialization of Compound and/or
Product, all Know-How Controlled by GSK, its Affiliate or a Third Party on
behalf of GSK or its Affiliate at any time during the Term, excluding any Abbott
Know-How or Myogen Know-How.

     "GSK Intellectual Property" means GSK Know-How and GSK Patent Rights,
collectively.

     "GSK Marks" will have the meaning set forth in Section 5.2(d).

     "GSK Patent Rights" means Patent Rights, including the interest of GSK
and/or its

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


                                       5
<PAGE>

Affiliates in Joint Inventions, Controlled by GSK and/or its Affiliates on the
Effective Date or at any time during the Term, excluding the Abbott Patent
Rights and the Myogen Patent Rights.

     "GSK Publication" will have the meaning set forth in Section 13.3(b).

     "GSK Sponsored New Development Activity" will have the meaning set forth in
Section 4.3(d).

     "GSK Territory" means all countries and territories of the world that are
not included in the Myogen Territory.

     "ICH" mean International Committee on Harmonization developed through a
collaboration between the FDA and regulatory agencies in the European Union and
Japan to harmonize regulatory requirements to produce marketing applications
acceptable to the countries of the European Union, Japan and the United States.

     "Indemnitee" will have the meaning set forth in Section 14.4.

     "Indemnitor" will have the meaning set forth in Section 14.4.

     "Initial Royalty" will have the meaning set forth in Section 9.2(a)(i).

     "Joint Inventions" will have the meaning set forth in Section 10.2.

     "JNDA" means a Japanese New Drug Application, which is filed with the MHLW
in order to gain the MHLW's approval to Commercialize a pharmaceutical product
in Japan for the indications set forth in the Japanese New Drug Application.

     "Joint New Development Activity" will have the meaning set forth in Section
4.3(b).

     "Joint Project Team" will have the meaning set forth in Section 3.2(a).

     "Joint Steering Committee" will have the meaning set forth in Section
3.1(a).

     "Know-How" means any proprietary technology, information, methods of use,
processes, techniques, ideas or inventions (excluding any inventions disclosed
in any patent or patent application) which are directly related to or used in
connection with the Compound and/or Product, including any trade secrets and any
other technical information relating to Development, Manufacture and/or
Commercialization of the Compound and/or Product, excluding any Patent Rights.

     "Losses" will have the meaning set forth in Section 14.2.

     "MAA" means a Marketing Authorization Application, which is filed with the
EMEA for review and recommendation to the European Commission to approve such
Marketing Authorization Application for the Commercializing of a pharmaceutical
product in the European

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


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Economic Area for the indications set forth in the Marketing Authorization
Application.

     "Major Country" means the following countries: [..**..] Australia, [..**..]
Canada, [..**..] Japan, [..**..].

     "Major European Market Countries" means the following countries: France,
Germany, Italy, Spain and the United Kingdom.

     Manufacturing" or "Manufacture" means all the activities relating to
production of Compound and/or Product, including without limitation, purchasing
raw materials, quality control and assurance, filling, finishing, labeling,
packaging, qualified person release, holding, shipping and storage and the tests
and analyses conducted in connection therewith. Manufacturing excludes
activities relating to Development or Commercialization.

     "MHLW" means the Japanese Ministry of Health, Labour and Welfare or any
successor agency thereto.

     "Milestone Payment" will have the meaning set forth in Section 9.1(a).

     "Milestones" will have the meaning set forth in Section 9.1(a).

     "Myogen" will have the meaning set forth in the Preamble.

     "Myogen Know-How" means, solely to the extent necessary or useful for
purposes of Development, Manufacture and/or Commercialization of Compound and/or
Product in the Field, any Know-How that is Controlled by Myogen or its
Affiliates or a Third Party on behalf of Myogen or its Affiliate on the
Effective Date or at any time during the Term, including, without limitation,
Development Information but excluding any Abbott Know-How and GSK Know-How.

     "Myogen Indemnitees" will have the meaning set forth in Section 14.2.

     "Myogen Intellectual Property" means Myogen Know-How and Myogen Patent
Rights, collectively.

     "Myogen Inventions" will have the meaning set forth in Section 10.2.

     "Myogen Marks" will have the meaning set forth in Section 5.3(d).

     "Myogen Patent Rights" means Patent Rights, including the interest of
Myogen and/or its Affiliates in Joint Inventions, Controlled by Myogen and/or
its Affiliates on the Effective Date or at any time during the Term, excluding
the Abbott Patent Rights and GSK Patent Rights. A list of issued patents and PCT
applications within the Myogen Patent Rights is attached hereto as Exhibit D,
and Myogen will update such Exhibit at least once each Calendar Year during the
Term, or promptly after GSK's reasonable written request, which request will not
be made by GSK more than twice in any Calendar Year during the Term.

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


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     "Myogen Publication" will have the meaning set forth in Section 13.3(a).

     "Myogen Sponsored New Development Activity" will have the meaning set forth
in Section 4.3(c).

     "Myogen Territory" means the United States, and any other country in which
this Agreement is terminated pursuant to Section 6.2, Section 6.5, Section 11.4
or Section 11.7.

     "Myogen Trademarks" means the trademarks set forth on Exhibit E, attached
hereto and incorporated herein, and Myogen will update such Exhibit at least
once each Calendar Year during the Term, or promptly after GSK's reasonable
written request, which request will not be made by GSK more than twice in any
Calendar Year during the Term.

     "NDA" means a New Drug Application, which is filed with the FDA in order to
gain the FDA's approval to Commercialize a pharmaceutical product in the United
States for the indications set forth in the New Drug Application.

     "New Development Activity" will have the meaning set forth in Section
4.3(a).

     "Net Sales" means the gross sales of Compound and/or Product by GSK, its
Affiliates or Sublicensees to Third Parties (including, but not limited to,
pharmaceutical wholesalers, pharmacies, hospitals or dispensing physicians), in
arm's length transactions for which revenue is actually received by GSK, its
Affiliates, Sublicensees, less any of the following charges or expenses that are
incurred in connection with such gross sales:

          (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 governmental 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 GSK, its Affiliate or Sublicensee; 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 GSK, its Affiliates or
Sublicensees.

Any sales of Compound and/or Product between GSK, its Affiliates and its or
their Sublicensees, for resale, will be excluded from the computation of Net
Sales; provided, however, that the revenue received from the subsequent sale of
such Compound and/or Product by GSK, its Affiliates and its or their Sublicenses
will be included within Net Sales.

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


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<PAGE>

     "New Field" will have the meaning set forth in Section 2.3(a).

     "New Field License Agreement" will have the meaning set forth in Section
2.3(d).

     "PAH" means pulmonary arterial hypertension.

     "Party" or "Parties" will have the meaning set forth in the Preamble.

     "Patent Prosecution" means, with respect to a Patent Right, (i) preparing,
filing, prosecuting, maintaining, extending and listing, including reissue and
reexamination of, such Patent Right (including reissue, continuing, divisional
and substitute applications and any foreign counterparts thereof) and (ii)
managing any interference or opposition proceedings relating to the foregoing.

     "Patent Rights" means all patents and patent applications including
continuations, continuations-in-part, divisions, patents of addition, patents
issuing from reissue, re-examination, renewal or extension proceedings, utility
models, all Supplemental Protection Certificates and any foreign counterparts
thereof, including PCTs existing as of the Effective Date and/or during the
Term, that generally or specifically claim or cover the making, having made,
use, sale, offering for sale and import of Compound and/or Product in the Field
in the Territory.

     "Person" means any individual, corporation, partnership, firm, association,
joint venture, joint stock company, trust or other entity, or any government or
regulatory administrative or political subdivision or agency, department or
instrumentality thereof.

     "Presentation" means the method of administration of a pharmaceutical
substance into the human body, including solid oral (including tablets,
capsules, gelcaps and caplets), other oral (including suspension and solution),
parenteral (including transdermal, intramuscular, subcutaneous and intravenous),
suppository, inhaled or intranasal.

     "Product" means any pharmaceutical composition containing the Compound,
whether or not as the sole active ingredient, and regardless of formulation,
dosage, or form.

     "Recipient" will have the meaning set forth in Section 13.1(a).

     "Reduced Royalty" will have the meaning set forth in Section 9.2(b)(i).

     "Regulatory Approval" means an approval, license, registration, and/or
authorization necessary for the Development, Manufacture and/or
Commercialization of a prescription pharmaceutical product in the Territory,
including, without limitation, the Shonin in Japan, but not including any
approvals for pricing and/or reimbursement.

     "Regulatory Approval Applications" means an application for obtaining a
Regulatory Approval, together with all documents, data, and information included
with such application.

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


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<PAGE>

     "Regulatory Authority" means any or all national, supranational, regional,
state, or local regulatory agency, department bureau, commission, council, or
other government entity involved in the granting of Regulatory Approval for a
pharmaceutical product in the Territory.

     "Right of Negotiation" will have the meaning set forth in Section 2.3(a).

     "Right of Negotiation Notice" will have the meaning set forth in Section
2.3(b).

     "Right of Negotiation Period" will have the meaning set forth in Section
2.3(d).

     "Royalty" or "Royalties" means the Initial Royalty and the Reduced Royalty,
collectively.

     "Sublicensee" means a Third Party to whom a Party or its Affiliate
sublicenses or otherwise transfers its right to Develop, Manufacture and/or
Commercialize Compound and/or Product in a country in the GSK Territory or
Myogen Territory, as applicable in accordance with the terms of this Agreement,
and in consideration for such transfer of rights, such Third Party pays such
Party or Affiliate a percentage of, or profit share on, such Third Party's sales
of Compound and/or Product in such country.

     "Supply Agreement" will have the meaning set forth in Section 7.1(g).

     "Term" will have the meaning set forth in Section 11.1.

     "Territory" means the GSK Territory and Myogen Territory, collectively.

     "Third Party" means any Person other than the Parties or their respective
Affiliates.

     "Third Party Payments" will have the meaning set forth in Section 9.2(c).

     "United States" or "U.S." means the fifty (50) states of the United States
of America, the District of Columbia, Puerto Rico and the territories and
possessions of the United States.

     "Wholesaler" means a Third Party engaged by a Party or its Affiliates in a
country in the GSK Territory or Myogen Territory, as applicable under the terms
of this Agreement, whose function is solely to re-sell or distribute and not in
any way promote Product purchased from such Party to other Third Party
purchasers.

     Section 1.2 Clarification. The word "including" or any variation thereof
means "including without limitation" and the word "including" or any variation
thereof will not be construed to limit any general statement which it follows to
the specific or similar items or matters immediately following it. The word
"annual" means each period during the Term from January until December, pro
rated as necessary. The phrase "pricing and/or reimbursement approval
commercially acceptable to GSK" or similar phrases used in this Agreement shall
mean pricing and/or reimbursement approval, as applicable, in the subject
country in the GSK Territory which is commercially acceptable to GSK, as
determined by GSK in its sole discretion,

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provided that any such pricing and/or reimbursement approval shall be deemed to
be commercially acceptable to GSK if GSK, any of its Affiliates, or any of its
Sublicensees achieves the First Commercial Sale of the Product in such country.

                                   ARTICLE II

                                 LICENSE GRANTS

     Section 2.1 Grants to GSK Under Abbott and Myogen Intellectual Property.

          (a) License in GSK Territory.

               (i) Abbott Intellectual Property. Subject to the terms and
conditions of this Agreement and the Abbott Agreement, including Abbott's
internal research license as set forth in section 3.2 of the Abbott Agreement,
Myogen hereby grants to GSK an exclusive sublicense, with the right to grant
further sublicenses as provided in Section 2.2, under the Abbott Intellectual
Property to make, have made, use, sell, offer for sale and import Compound and
Product in the Field in the GSK Territory.

               (ii) Myogen Intellectual Property. Subject to the terms and
conditions of this Agreement, Myogen hereby grants to GSK an exclusive license,
with the right to grant sublicenses as provided in Section 2.2, under the Myogen
Intellectual Property to make, have made, use, sell, offer for sale and import
Compound and Product in the Field in the GSK Territory in order for GSK to
Develop, Manufacture and Commercialize Compound and Product in accordance with
the terms and conditions of this Agreement.

               (iii) Notwithstanding the foregoing or any other provision
contained in this Agreement, Myogen shall retain the right, with the right to
grant further sublicenses upon obtaining the prior written consent of GSK, which
consent will not be unreasonably withheld, under the Abbott Intellectual
Property and the Myogen Intellectual Property, to make, have made and import
Compound, and make and have made Product, in each case, in the GSK Territory for
the sole purpose of exporting such Compound and/or Product from the GSK
Territory for Development, Manufacture and Commercialization of such Compound
and Product in the Myogen Territory. For the avoidance of doubt, Myogen will
have no right to use, sell and offer for sale Compound, or use, sell, offer for
sale and import Product, in each case in the Field in the GSK Territory (as such
term is defined from time-to-time).

          (b) License in Myogen Territory.

               (i) Abbott Intellectual Property. Subject to the terms and
conditions of this Agreement and the Abbott Agreement, Myogen hereby grants to
GSK a non-exclusive sublicense, with the right to grant further sublicenses as
provided in Section 2.2, under the Abbott Intellectual Property, to make, have
made and import Compound and to make and have made Product, in each case in the
Field in the Myogen Territory for the sole purpose of exporting such Compound
and/or Product from the Myogen Territory for Development, Manufacture and

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Commercialization of such Compound and Product in the Field in the GSK
Territory. For the avoidance of doubt, GSK shall have no right to use, sell,
offer for sale or import Compound or Product in the Myogen Territory.

               (ii) Myogen Intellectual Property. Subject to the terms and
conditions of this Agreement, Myogen hereby grants to GSK a non-exclusive
license, with the right to grant sublicenses as provided in Section 2.2, under
the Myogen Intellectual Property, to make, have made and import Compound and
make and have made Product, in each case in the Field in the Myogen Territory
for the sole purpose of exporting such Compound and/or Product from the Myogen
Territory for Development, Manufacture and Commercialization of such Compound
and Product in the Field in the GSK Territory.

     Section 2.2 GSK's Right to Grant Sublicenses.

          (a) GSK will have the right to sublicense any or all of its rights
under the Abbott Intellectual Property and Myogen Intellectual Property as
provided in Section 2.1(a) and (b) to its Affiliates, without the consent of
Myogen.

          (b) GSK will have the right to sublicense its rights under the Abbott
Intellectual Property and Myogen Intellectual Property as provided in Section
2.1(a) and (b) to Third Parties to make, have made and import Compound and/or
Product in the Field in the Myogen Territory, for the sole purpose of exporting
such Compound and/or Product from the Myogen Territory for Development,
Manufacture and Commercialization of such Compound and Product in the GSK
Territory in each case upon providing prior written notice to Myogen. If Myogen
does not object to the sublicense by GSK of its rights as provided in this
Section 2.2(b), or if Myogen does not provide any response to GSK, in each case
within [..**..] Business Days after receiving written notice thereof from GSK,
GSK will be free to sublicense its rights as set forth in this Section 2.2(b).
If Myogen objects to the sublicense by GSK of its rights as provided in this
Section 2.2(b) within [..**..] Business Days after receiving written notice
thereof from GSK, GSK will afford Myogen with a reasonable opportunity to meet
and discuss with GSK Myogen's objection to such sublicense, which objection GSK
will consider in good faith but to which GSK will have no obligation to comply.

          (c) GSK will have the right to sublicense any or all of its other
rights, beyond those set forth in Section 2.2(b) above, under the Abbott
Intellectual Property and Myogen Intellectual Property as provided in Sections
2.1(a) as follows:

               (i) to any Third Party who GSK may engage to provide services to
or on behalf of GSK in the GSK Territory relating to this Agreement (including a
Clinical Research Organization (CRO)), except as otherwise provided in this
Section 2.2(c), without the consent of Myogen;

               (ii) to any Third Party who GSK may engage as a Wholesaler in the
GSK Territory, without the consent of Myogen;

               (iii) to any Third Party who GSK may engage as a Distributor of

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Product in a Major European Market Country(ies) or Major Country(ies), with the
prior written consent of Myogen which consent may be withheld for any reason in
Myogen's sole discretion;

               (iv) to any Third Party who GSK may engage as a Distributor of
Product in a country or countries other than a Major European Market Country or
Major Country, without the consent of Myogen; and

               (v) to any Sublicensee with the prior written consent of Myogen,
which consent may be withheld for any reason in Myogen's sole discretion.

Any agreement entered into by GSK pursuant to this Section 2.2(c) will
automatically terminate as to Product, without any action by GSK or such Third
Party or Sublicensee, upon the termination of this Agreement or the Abbott
Agreement.

          (d) GSK shall remain responsible for any breach by a Sublicensee of
the terms of this Agreement or the applicable sublicense agreement. Any
agreement entered into by GSK with a Third Party pursuant to Section 2.2(c)
shall be in writing and shall include provisions acknowledging that such
agreement is subject to the license granted to Myogen under the Abbott Agreement
and to the license granted to GSK under this Agreement, and with respect to
agreements entered into pursuant to Section 2.2(c)(v), that each Sublicensee
shall make reports and keep and maintain records of sales to at least the same
extent required under this Agreement and the Abbott Agreement, allowing Myogen
and Abbott the same access and audit rights permitted under this Agreement and
the Abbott Agreement. GSK shall provide Myogen with a copy of each agreement
entered into by GSK pursuant to Section 2.2(c)(iii) or (v), which copy Myogen
may provide to Abbott in accordance with the last sentence in Section 4.7 of the
Abbott Agreement. Myogen will designate such information as the Confidential
Information (as defined in Section 1.6 of the Abbott Agreement) of Myogen and
notify Abbott in writing of its obligation to maintain the confidentiality of
such agreement in accordance with the terms and conditions of Section 7 of the
Abbott Agreement. Notwithstanding the foregoing, this Section 2.2(d) will not
apply to, and GSK will have no obligations under this Section 2.2(d) with
respect to, to any agreements with any Third Party covered by Section 2.2(c)(iv)
above.

     Section 2.3 Right of Negotiation for Rights Outside of the Field.

          (a) Each time during the Term that Myogen, on its own or through any
of its Affiliates or any Third Party, decides to make, have made, use, sell,
offer for sale and/or import Compound and/or Product for a therapeutic use
outside of the Field in the GSK Territory (each therapeutic use referred to as a
"New Field"), Myogen will provide prior written notice to GSK and thereby grant
to GSK an exclusive option to negotiate with Myogen for an exclusive license
under the Abbott Intellectual Property and Myogen Intellectual Property to make,
have made, use, sell, offer for sale and import Compound and Product in such New
Field (each such notice referred to as a "Right of Negotiation").

          (b) GSK must exercise a Right of Negotiation by providing written
notice to Myogen (each such notice referred to as a "Right of Negotiation
Notice") within [..**..] calendar days after receiving written notice from
Myogen as provided in Section 2.3(a) of such Right of

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Negotiation.

          (c) If GSK does not submit a Right of Negotiation Notice to Myogen as
provided in Section 2.3(b) prior to the expiration of the [..**..] calendar day
period referenced in Section 2.3(b), the corresponding Right of Negotiation will
immediately terminate at 12:01 a.m. Eastern Standard Time on the calendar day
that is immediately after last calendar day of such [..**..] calendar day period
and Myogen will have no further obligation to GSK with respect to such Right of
Negotiation; provided, however, that in Developing, Manufacturing and/or
Commercializing Compound and/or Product in such New Field in the GSK Territory
during the Term, Myogen covenants and agrees that it will not, and will cause
its Affiliates and any Third Party not to, knowingly, materially and adversely
affect GSK's right and ability to Develop, Manufacture and Commercialize Product
in the Field in the GSK Territory.

          (d) If GSK exercises a Right of Negotiation by providing a Right of
Negotiation Notice as provided in Section 2.3(b), the Parties will in good faith
negotiate during the Right of Negotiation Period a license agreement pursuant to
which GSK would obtain an exclusive license under the Abbott Intellectual
Property and Myogen Intellectual Property to make, have made, use, sell, offer
for sale and import Compound and Product in the New Field in the GSK Territory
(the "New Field License Agreement"). The "Right of Negotiation Period" will be
the period that commences on the date on which GSK provides Myogen with a Right
of Negotiation Notice as provided in Section 2.3(b) (for the purposes of this
Section 2.3(d) only, the "commencement date") and expires at 12:01 a.m. Eastern
Standard Time on the day immediately following the [..**..] day after the
commencement date. Each such Right of Negotiation Period may be extended upon
the mutual written agreement of the Parties prior to the expiration thereof as
provided in Section 2.3(e) or earlier terminated by the termination of this
Agreement. Notwithstanding the foregoing, GSK will have the right, at any time
and for any reason during a Right of Negotiation Period, to terminate in writing
such Right of Negotiation Period which would terminate the corresponding Right
of Negotiation.

          (e) In the event the Parties have not executed the New Field License
Agreement during the Right of Negotiation Period, after starting to negotiate
the terms and conditions thereof in good faith: (i) the Parties may, upon the
Parties' mutual written agreement prior to the expiration of such Right of
Negotiation Period, extend such Right of Negotiation Period for successive
additional periods of [..**..] Business Days; or (ii) if not extended by the
Parties as provided in (i), such Right of Negotiation Period will expire as
provided in Section 2.3(d) and Myogen will have no further obligation to GSK
with respect to such Right of Negotiation or Compound or Product in such New
Field; provided, however, that in Developing, Manufacturing and/or
Commercializing Compound and/or Product in such New Field in the GSK Territory
during the Term, Myogen covenants and agrees it will not, and will cause its
Affiliates and any Third Party not to, knowingly, materially and adversely
affect GSK's right and ability to Develop, Manufacture and Commercialize Product
in the Field in the GSK Territory.

     Section 2.4 Grants to Myogen under GSK Intellectual Property.

          (a) Subject to the terms and conditions of this Agreement, GSK hereby
grants to Myogen: (i) a non-exclusive, royalty-free license under the GSK
Intellectual Property to

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make, have made, use, sell, offer for sale and import Compound and Product in
the Myogen Territory; and (ii) subject to Section 2.3, a non-exclusive,
royalty-free license under the GSK Intellectual Property to make, have made,
use, sell, offer for sale and import Compound and Product outside the Field in
the GSK Territory.

          (b)   (i) Myogen will have the right to sublicense any or all of its
rights under the GSK Intellectual Property as provided in Section 2.4(a) to its
Affiliates, without the consent of GSK.

               (ii) Myogen will have the right to sublicense its rights under
the GSK Intellectual Property as provided in Section 2.4(a) to Third Parties to
make, have made and import Compound and/or Product in the Myogen Territory and
to make, have made and import Compound and/or Product outside of the Field in
the GSK Territory, in each case upon providing prior written notice to GSK. If
GSK does not object to the sublicense by Myogen of its rights as provided in
this Section 2.4(b)(ii), or if GSK does not provide any response to Myogen, in
each case within [..**..] Business Days after receiving written notice thereof
from Myogen, Myogen will be free to sublicense its rights as set forth in this
Section 2.4(b)(ii). If GSK objects to the sublicense by Myogen of its rights as
provided in this Section 2.4(b)(ii) within [..**..] Business Days after
receiving written notice thereof from Myogen, Myogen will afford GSK with a
reasonable opportunity to meet and discuss with Myogen GSK's objection to such
sublicense, which objection Myogen will consider in good faith but to which
Myogen will have no obligation to comply.

               (iii) Myogen will have the right to sublicense any or all of its
other rights beyond those set forth in Section 2.4(b)(ii) above under the GSK
Intellectual Property as provided in Section 2.4(a) to Third Parties, upon
obtaining the prior written consent of GSK, which consent will not be
unreasonably withheld. Notwithstanding the foregoing, Myogen will have the right
at any time during the Term, to sublicense its rights under Section 2.4(a):

                    (A) to any Third Party who Myogen may engage to provide
services to or on behalf of Myogen relating to this Agreement (including a
Clinical Research Organization (CRO)), without the consent of GSK;

                    (B) to any Third Party who Myogen may engage as a
Wholesaler, without the consent of GSK;

                    (C) to any Third Party who Myogen may engage as a
Distributor of Product, without the consent of GSK; and

                    (D) to any Sublicensee with the prior written consent of GSK
which consent may not be unreasonably withheld;

provided, however that, except as set forth in Section 11.9(a)(iv), any
agreement entered into by Myogen pursuant to this Section 2.4(b)(iii) will
automatically terminate as to Product, without any action by Myogen or such
Third Party or Sublicensee, upon the termination of this Agreement.

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               (iv) Myogen will remain responsible for any breach by a
Sublicensee of the terms of this Agreement or the applicable sublicense
agreement. Any agreement entered into by Myogen pursuant to this Section 2.4(b)
will be in writing and will include provisions acknowledging that such agreement
is subject to the license granted to Myogen under this Agreement and that such
agreement shall be automatically terminated upon termination of this Agreement.
Myogen will provide GSK with a copy of each such agreement entered into by
Myogen pursuant to Section 2.4(b)(iii)(D).

     Section 2.5 Affiliates. Notwithstanding anything in this Agreement to the
contrary, either Party may contract or agree with one or more of its Affiliates
to have such Affiliate perform any of such Party's obligations herein. In no
event will such use of an Affiliate be deemed to relieve a Party of its
liabilities or obligations to the other Party under this Agreement; provided,
that performance of an obligation hereunder by an Affiliate of a Party will be
attributed to such Party. Each Party expressly acknowledges and agrees that it
will remain fully and unconditionally obligated and responsible for the full and
complete performance of all of its obligations under the terms and conditions of
this Agreement, whether or not such performance is carried out by such Party or
any of its Affiliates.

     Section 2.6 Abbott Agreement.GSK acknowledges that the sublicense granted
hereunder to GSK under the Abbott Intellectual Property is governed by the terms
of the Abbott Agreement. GSK agrees to abide by the terms and conditions of the
Abbott Agreement, where and to the extent applicable. Further, the Parties
acknowledge and agree as follows:

          (a) Pursuant to Section 3.2 of the Abbott Agreement, Abbott and its
Affiliates have the right to develop and commercialize the Compound for [..**..]
(the term [..**..] is defined in Section [..**..] of the Abbott Agreement).
Subject to any confidentiality restrictions imposed by Abbott, Myogen will
within five (5) Business Days inform GSK in writing of any consultation by
Abbott with Myogen regarding Abbott or its Affiliates conducting any research
and development activities involving the use of Compound in animals or humans in
which Abbott apprises Myogen of the scope and nature of such activities.
Further, subject to any confidentiality restrictions imposed by Abbott, Myogen
will within five (5) Business Days after receipt from Abbott, provide GSK with
copies of all studies relating to the Compound performed by Abbott or its
Affiliates, which shall be treated as the Confidential Information of Myogen and
subject to Article XIII.

          (b) To the extent permitted under Applicable Law, pursuant to Section
4.8 of the Abbott Agreement, in the event that the Abbott Agreement is
terminated by Abbott for any reason as set forth in Article 8 therein or by
Myogen under Section 8.2 therein, Abbott will have an exclusive license under
all [..**..] (as such term is defined in Section [..**..] of the Abbott
Agreement) made solely by GSK and/or its Affiliates.

          (c) Myogen will not, and will cause its Affiliates and Sublicensees
not to: (i) on its or their own or in agreement with Abbott, terminate the
Abbott Agreement or supplement, amend or modify the Abbott Agreement in any way
that materially and adversely affects GSK rights under the Abbott Intellectual
Property or in this Agreement without the prior written

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consent of GSK; provided, however, that Myogen will provide GSK with written
notice prior to making any amendment to the Abbott Agreement; (ii) initiate any
dispute resolution proceedings with Abbott under the Abbott Agreement without
the prior written consent of GSK, which shall not be unreasonably withheld; or,
(iii) send written notice to Abbott of any monetary or non-monetary breach by
Abbott of the Abbott Agreement as provided in Section 8.3 of the Abbott
Agreement without providing at least ten (10) calendar days' prior written
notice to GSK.

          (d) Within two (2) Business Days of receiving written notice of a
monetary breach or non-monetary material breach from Abbott as provided in
Section 8.3 of the Abbott Agreement, Myogen will provide GSK with a copy of such
notice and meet with GSK upon GSK's request to discuss whether a material breach
has occurred, whether Myogen should challenge the existence of the breach by
invoking the ADR (as defined in the Abbott Agreement) procedure set forth in
Exhibit D of the Abbott Agreement (which Myogen will not do without prior
consultation with GSK) and the options to cure such breach, if applicable. GSK
may, in its sole discretion but after consultation with Myogen, determine to
cure any such breach of Myogen under the Abbott Agreement if Myogen has not
already done so; provided, however, that (i) if GSK cures any monetary breach of
Myogen, GSK will have the right to credit all of such amount paid to Abbott
against any Milestone Payments and/or Royalties owed to Myogen as provided in
Article IX of this Agreement; and (ii) if GSK cures any non-monetary breach of
Myogen, GSK will have the right to credit any and all reasonable, documented
direct costs and expenses incurred by GSK in curing such non-monetary breach
against any Milestone Payments and/or Royalties owed to Myogen as provided in
Article IX of this Agreement; however, in the case of (i) and (ii) above, only
to the extent that such breach was not directly or indirectly a result of an act
or omission by GSK, its Affiliates or sublicensees, including any breach of this
Agreement.

     Section 2.7 Reservation of Rights. No right or license under any
intellectual property right Controlled by either Party is granted or implied
except as expressly granted in this Agreement. Except for the rights
specifically granted in this Agreement, each Party expressly reserves all rights
Controlled by it or its Affiliates to all its products and intellectual
property, and reserves the right to utilize or allow its Affiliates or Third
Parties to utilize such products and intellectual property rights in any manner
not inconsistent with the terms of this Agreement.

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                                   ARTICLE III

                                   GOVERNANCE

     Section 3.1 Joint Steering Committee.

          (a) Within fifteen (15) Business Days after the Effective Date, the
Parties will form a committee (the "Joint Steering Committee"), which will serve
as a global oversight committee that is responsible for establishing, reviewing
and revising (i) the overall Development strategy for Compound and Product in
the Field in the Territory, with input from the Joint Project Team, including,
without limitation, approval of all updates and revisions to the Development
Plan as provided in Section 4.1; (ii) the overall Commercialization strategy for
Compound and Product in the Field in the Territory (other than pricing and
reimbursement for Product), with input from the Global Brand Team; and (iii) the
overall Manufacturing strategy for Compound and Product in the Field in the
Territory. The Joint Steering Committee will oversee the activities of the Joint
Project Team and Global Brand Team, and will settle unresolved disputes or
disagreements of the Joint Project Team and Global Brand Team.

          (b) Each Party will designate at least three (3) and up to five (5)
representatives for membership on the Joint Steering Committee. Each Party's
representatives on the Joint Steering Committee will be employees from among the
project management, clinical, regulatory, commercial and alliance management
departments of such Party and will have the authority to make decisions on
behalf of such Party within the constraints of necessary internal approvals
(which will have been previously obtained to the extent practicable). Each Party
will have one (1) vote on each matter brought before the Joint Steering
Committee. At least three (3) members from each Party (or their designees with
the authority to make decisions on behalf of such Party) must be present at a
meeting of the Joint Steering Committee to represent a quorum for voting
purposes. Each Party may from time to time and in their sole discretion include
additional non-voting ad-hoc representatives to participate in Joint Steering
Committee meetings to address specific issues. The Joint Steering Committee will
be co-chaired by a Myogen member of the Joint Steering Committee and a GSK
member of the Joint Steering Committee and each Party may, from time to time and
in its sole discretion, change the member of such Party who serves as such
Party's designee for co-chairperson of the Joint Steering Committee.

          (c) The first meeting of the Joint Steering Committee may be a face to
face meeting at a location agreed to by the Parties and will occur within twenty
(20) Business Days after formation of the Joint Steering Committee; provided,
however that if the first meeting of the Joint Steering Committee is not face to
face, the next meeting of the Joint Steering Committee, which must occur within
the immediately succeeding Calendar Quarter, must be a face to face meeting at a
location agreed to by the Parties. The purpose of the initial meeting will be to
agree on an operational charter that will set forth the principles and
guidelines for the governance and operation of the Joint Steering Committee
(e.g., how the co-chairs of the Joint Steering Committee will share
responsibilities for determining meeting agendas and the drafting of minutes,
etc.). Thereafter, meetings will be held at least once during each Calendar
Quarter, or more or less frequently as the Joint Steering Committee members may
agree. The location of

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such meetings will alternate between sites selected by Myogen and GSK, unless
otherwise agreed upon between the Parties. Joint Steering Committee meetings
need not necessarily be face-to-face meetings but, upon the agreement of both
Parties, can be via other methods of communication such as teleconferences
and/or videoconference. Each Party will bear all expenses it incurs in regard to
participating in all meetings of the Joint Steering Committee, including all
travel and living expenses. Minutes of each Joint Steering Committee meeting
will be prepared as agreed to by the co-chairpersons and distributed to the
members of the Joint Steering Committee for review and comment within twenty
(20) Business Days after each meeting of the Joint Steering Committee, and will
be approved as the first order of business at the immediately succeeding Joint
Steering Committee meeting.

          (d) All decisions of the Joint Steering Committee will be by unanimous
vote, which decisions will be final and binding on the Parties. Should the
members of the Joint Steering Committee become deadlocked on an issue after a
good faith but unsuccessful effort to break such deadlock, the issue will be
presented to the senior management of Myogen and GSK as follows for resolution,
which resolution will be final and binding on the Parties: (i) to the chief
executive officer of Myogen or his/her designee and the head of the
cardiovascular therapeutic area within the research and development organization
at GSK or his/her designee for issues involving the Development of Compound
and/or Product; and (ii) to the chief executive officer of Myogen or his/her
designee and the president of pharmaceuticals for Europe at GSK or his/her
designee for all issues other than those relating to Development of Compound
and/or Product. If the dispute remains unresolved after thirty (30) Business
Days following the date on which such dispute is referred to the senior
management of each Party as provided in this Section 3.1(d), then (w) Myogen
will make the final and binding decision with respect to any dispute involving
the Development, Manufacture and Commercialization of Compound and/or Product in
the Myogen Territory, provided that such decision cannot be inconsistent with
the terms of this Agreement, the Development Plan and the Global Marketing Plan,
and such decision cannot materially and adversely affect GSK's right and ability
to Develop, Manufacture and Commercialize Product in the GSK Territory; (x) GSK
will make the final and binding decision with respect to any dispute involving
the Development, Manufacture and Commercialization of Compound and/or Product in
the GSK Territory, provided that such decision cannot be inconsistent with the
terms of this Agreement, the Development Plan and the Global Marketing Plan, and
such decision cannot materially and adversely affect Myogen's right and ability
to Develop, Manufacture and Commercialize Product in the Myogen Territory; (y)
any such decision, to the extent not specific to the Myogen Territory or the GSK
Territory, will be resolved in accordance with Section 14.1; and (z) any and all
issues relating to safety will be resolved as set forth in Section 3.4.

          (e) The Joint Steering Committee will have only such powers as are
specifically delegated to it in this Agreement, and will have no power to amend
this Agreement or waive a Party's rights or obligations under this Agreement.

     Section 3.2 Joint Project Team.

          (a) Within thirty (30) Business Days after the Effective Date, the
Parties will form a team (the "Joint Project Team") whose mandate will be to (i)
make strategic and

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EXCHANGE COMMISSION PURSUANT TO RULE 24B-2 OF THE SECURITIES EXCHANGE ACT OF
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operational recommendations to the Joint Steering Committee on matters relating
to the Development of Compound and Product in the Field in the Territory; (ii)
update the Development Plan during each Calendar Year and obtain the Joint
Steering Committee's approval of all such updates to the Development Plan, as
provided in Section 4.1; and (iii) oversee, manage and implement the Development
of Product in the Field in the Territory as provided in Article 4, including,
without limitation, appropriate safety reporting systems, pre-commercial
manufacturing and technology transfer.

          (b) Each Party will designate at least three (3), but not more than
five (5) representatives for membership on the Joint Project Team. Each Party
may, from time to time and in their sole discretion, determine from which
departments of such Party (e.g., scientific, clinical development, commercial
development, regulatory, manufacturing, etc.) representatives on the Joint
Project Team will come. Each Party will have one (1) vote on each matter brought
before the Joint Project Team. At least three (3) members from each Party (or
their designees with the authority to make decisions on behalf of such Party)
must be present at a meeting of the Joint Project Team to represent a quorum for
voting purposes. Each Party may from time to time and in their sole discretion
include additional non-voting ad-hoc representatives to participate in Joint
Project Team meetings to address specific issues. The Joint Project Team will be
co-chaired by a Myogen member and a GSK member.

          (c) The first meeting of the Joint Project Team may be a face to face
meeting at a location agreed to by the Parties will occur within twenty (20)
Business Days after formation of the Joint Project Team; provided, however that
if the first meeting of the Joint Project Team is not face to face, the next
meeting of the Joint Project Team, which must occur within the immediately
succeeding Calendar Quarter, must be a face to face meeting at a location agreed
to by the Parties. The purpose of the initial meeting will be to agree on an
operational charter that will set forth the principles and guidelines for the
governance and operation of the Joint Project Team (e.g., how the co-chairs of
the Joint Project Team will share responsibilities for determining meeting
agendas and the drafting of minutes, etc.). Thereafter, meetings will be held at
least once during each Calendar Quarter, or more or less frequently as the Joint
Project Team members may agree. The location of such meetings will alternate
between sites selected by Myogen and GSK, unless otherwise agreed upon between
the Parties. Joint Project Team meetings need not necessarily be face-to-face
meetings but, upon the agreement of both Parties, can be via other methods of
communication such as teleconferences and/or videoconference; provided, however
that unless otherwise agreed to by the Parties, Joint Project Team meetings will
be face-to-face meetings not less than twice per year. Each Party will bear all
expenses it incurs in regard to participating in all meetings of the Joint
Project Team, including all travel and living expenses. Minutes of each Joint
Project Team meeting will be prepared as agreed to by the co-chairpersons and
distributed to the members of the Joint Project Team for review and comment
within twenty (20) Business Days after each meeting of the Joint Project Team,
and will be approved as the first order of business at the immediately
succeeding Joint Project Team meeting.

          (d) All decisions of the Joint Project Team will be by unanimous vote,
which decision will be final and binding on the Parties. Should the members of
the Joint Project Team become deadlocked on an issue after a good faith but
unsuccessful effort to break such deadlock,

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the issue will be presented to the Joint Steering Committee for resolution as
set forth in Section 3.1(d).

     Section 3.3 Global Brand Team.

          (a) Within thirty (30) Business Days after the Effective Date, the
Parties will form a team (the "Global Brand Team") whose mandate will be to (i)
make strategic and operational recommendations to the Joint Steering Committee
on matters relating to the Commercialization of Compound and Product in the
Field in the Territory; (ii) draft the initial Global Marketing Plan, and update
such Global Marketing Plan during each Calendar Year and obtain the Joint
Steering Committee's approval of any such updates to the Global Marketing Plan,
as provided in Section 5.1; and (iii) oversee the Commercialization of Product
in the Field in the Territory by the Parties as provided in Article 5.

          (b) Each Party will designate at least three (3), but not more than
five (5) representatives for membership on the Global Brand Team. Each Party
may, from time to time and in their sole discretion, determine from which
departments of such Party representatives on the Global Brand Team will come.
Each Party will have one (1) vote on each matter brought before the Global Brand
Team. At least three (3) members from each Party (or their designees with the
authority to make decisions on behalf of such Party) must be present at a
meeting of the Global Brand Team to represent a quorum for voting purposes.
Either Party may from time to time and in their sole discretion include
additional non-voting ad-hoc representatives to participate in Global Brand Team
meetings to address specific issues. The Global Brand Team will be co-chaired by
a Myogen member and a GSK member.

          (c) The first meeting of the Global Brand Team will be a face to face
meeting at a location agreed to by the Parties and will occur within twenty (20)
Business Days after formation of the Global Brand Team. The purpose of the
initial meeting will be to agree on an operational charter that will set forth
the principles and guidelines for the governance and operation of the Global
Brand Team (how the co-chairs of the Global Brand Team will share
responsibilities for determining meeting agendas and the drafting of minutes,
etc.). Thereafter, meetings will be held at least once during each Calendar
Quarter, or more or less frequently as the Global Brand Team members may agree.
The location of such meetings will alternate between sites selected by Myogen
and GSK, unless otherwise agreed upon between the Parties. Global Brand Team
meetings need not necessarily be face-to-face meetings but, upon the agreement
of both Parties, can be via other methods of communication such as
teleconferences and/or videoconference. Each Party will bear all expenses it
incurs in regard to participating in all meetings of the Global Brand Team,
including all travel and living expenses. Minutes of each Global Brand Team
meeting will be prepared as agreed to by the co-chairpersons and distributed to
the members of the Global Brand Team for review and comment within twenty (20)
Business Days after each meeting of the Global Brand Team, and will be approved
as the first order of business at the immediately succeeding Global Brand Team
meeting.

          (d) All decisions of the Global Brand Team will be by unanimous vote,
which decision will be final and binding on the Parties. Should the members of
the Global Brand Team become deadlocked on an issue after a good faith but
unsuccessful effort to break such deadlock,

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the issue will be presented to the Joint Steering Committee for resolution as
set forth in Section 3.1(d).

     Section 3.4 Decisions Relating to Safety Concerns.

          (a) Development Activities. If a Party (the "requesting Party")
reasonably believes that patient safety may be compromised in any ongoing or
proposed or planned Development activity of the other Party involving a clinical
trial for the Product (the "developing Party"), such requesting Party may send
written notice to the developing Party requesting that the developing Party
modify, discontinue or not initiate, as applicable, such Development activity
(including, without limitation, any clinical trial) in the Territory. If the
developing Party does not modify or discontinue the conduct or planning of any
such Development activity within thirty (30) Business Days (or such shorter
period as may be required by applicable Regulatory Authorities) after receipt of
written request from the requesting Party as provided in this Section 3.4(a),
the requesting Party may request that such matter be presented to an independent
safety board for resolution. The independent safety board panel will be
comprised of three (3) panelists, one (1) of whom will be selected by GSK, one
(1) of whom will be selected by Myogen, and one (1) of whom will be selected by
the two (2) panelists selected by the Parties. No panelist of the independent
advisory board may be an employee of either Party or shall have had an
employment or consulting relationship with either Party within five (5) years of
his/her appointment. Each panelist shall disclose his/her prior employment and
consulting relationships and must have a background in clinical safety issues.
Each Party will bear the cost of its own designated panelist on the independent
safety board and will equally share the cost of the third panelist selected by
the other panelists. The Parties must present such matter to the independent
safety board for resolution within thirty (30) Business Days after a request is
made by the requesting Party, which decision of the independent safety board
regarding the continuation of any such Development activity must be agreed to by
a majority of the panelists and will be binding on the Parties.

          (b) Commercialization Activities. Without prejudice to the provisions
contained in Section 8.1(a), if GSK reasonably believes that patient safety may
be compromised at any time after the First Commercial Sale, GSK may terminate
this Agreement in accordance with Section 11.3.

          (c) Notification of Safety Concerns. After a Party reasonably believes
that patient safety may be compromised with respect to Product in the Field in
the Territory as described in Section 3.4(a) or 3.4(b), such Party will promptly
notify the other Party. Within two (2) Business Days after such notice is sent
by a Party, the Joint Steering Committee will meet to discuss how the Parties
will address the patient safety concern, whether as provided in Sections 3.4(a)
and 3.4(b) or in some other manner.

                                   ARTICLE IV

                       DEVELOPMENT AND REGULATORY FILINGS

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     Section 4.1 Development Plan. The initial Development Plan which has been
agreed to by the Parties as of the Effective Date, has been exchanged by the
Parties under separate cover. Not later than sixty (60) Business Days prior to
the end of each Calendar Year during the Term in which the Development Plan is
applicable, the Joint Project Team will update the Development Plan as required
and submit the updated Development Plan for review and approval by the Joint
Steering Committee.

     Section 4.2 Clinical/Non-Clinical Development Under the Development Plan.

          (a) Myogen will be solely responsible for conducting all clinical and
non-clinical Development activities that, as of the Effective Date, the Parties
believe are required in order for Myogen to obtain and maintain Regulatory
Approvals for Product in the Field in the United States as set forth in Section
4.4(b) and that, as of the Effective Date, the Parties believe are required in
order for GSK or its Affiliates to obtain and maintain Regulatory Approvals for
Product in the Field in Canada and the European Economic Area as set forth in
Section 4.4(a), in each case as set forth in the Development Plan exchanged by
the Parties on the Effective Date and in accordance with this Agreement, and as
directed by the Joint Project Team. The Development Plan exchanged by the
Parties on the Effective Date sets forth all such clinical and non-clinical
Development activities that the Parties believe are required in order for Myogen
to obtain and maintain Regulatory Approvals for Product in the Field in the
United States as set forth in Section 4.4(b) and that the Parties believe are
required in order for GSK or its Affiliates to obtain and maintain Regulatory
Approvals for Product in the Field in Canada and the European Economic Area as
set forth in Section 4.4(a), which Development activities will be conducted by
or on behalf of Myogen at Myogen's sole cost and expense (provided that Myogen
shall not be required to pay regulatory filing, submission or similar fees
relating to the GSK Territory). To the extent that Myogen initiates any such
Development activities after the Effective Date, Myogen will share the design of
any such Development activities with GSK and provide GSK with a reasonable
opportunity to review, comment on and modify such design in a manner consistent
with the requirements necessary for GSK to obtain and maintain Regulatory
Approval for Product in the Field in the GSK Territory. All clinical and
non-clinical Development activities other than as set forth in the Development
Plan exchanged by the Parties on the Effective Date or as provided in Section
4.4 shall be deemed to be New Development Activities and Myogen and GSK shall be
responsible for the costs and expenses related to such New Development
Activities as provided in Section 4.3. Myogen will preserve any and all raw data
generated from non-Good Laboratory Practices (GLP) studies, including, without
limitation, pharmacology studies and absorption, distribution, metabolism and
excretion (ADME) studies, until such time that GSK determines such raw data is
no longer needed by GSK or its Affiliates to obtain or maintain Regulatory
Approvals in the GSK Territory as provided in Section 4.4(a). After such time,
Myogen will notify GSK in writing prior to destroying any such raw data and
offer GSK an opportunity to retain such raw data at GSK's sole cost and expense.

          (b) Except as otherwise provided in Section 4.2(a) above, GSK will be
solely responsible for conducting all clinical and non-clinical Development
activities that are required in order for GSK or its Affiliates to obtain and
maintain Regulatory Approvals for Product in all countries in the GSK Territory
in accordance with this Agreement and as directed by the Joint Project Team.
Such Development activities shall be conducted by or on behalf of GSK at GSK's

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sole cost and expense. Notwithstanding the foregoing, Myogen will, as reasonably
requested by GSK and at Myogen's sole cost and expense (provided that documented
fees and expenses of any Third Party will be billed at cost to GSK), provide
support to GSK with respect to clinical and non-clinical Development activities
required to obtain and maintain Regulatory Approvals for Product in the GSK
Territory.

          (c) Each Party, as applicable, will use Commercially Reasonable
Efforts to execute and to perform, or cause to be performed, their respective
Development activities set forth in the Development Plan, in each case, in
compliance with Applicable Law, Good Clinical Practice and Good Laboratory
Practice. Each Party will at no cost or expense to the other Party provide such
other Party with copies of or access to any and all Development Information
generated or otherwise obtained (including information generated or obtained by
Affiliates or any Third Party on behalf of a Party, provided that the fees and
expenses of any Third Party will be billed at cost to the requesting Party) in
the Development of Compound and/or Product as provided in this Section 4.2
(including Development Information generated or otherwise obtained by GSK and/or
its Affiliates to support the initial JNDA filing), all of which Development
Information may be used by or on behalf of each Party in the Development,
Manufacture and/or Commercialization of Compound and/or Product in their
respective Territories, including, without limitation, in the preparation,
submission, filing, prosecution and maintenance of Regulatory Approvals for
Product in their respective Territories. Moreover, upon reasonable written
notice from a Party, the other Party will provide Regulatory Authorities with
access to any Development Information for inspection and/or review as may be
required under Applicable Law.

     Section 4.3 Development Outside of the Development Plan.

          (a) If, during the Term, either Party desires to Develop the Compound
and/or Product in the Field for new indications, new formulations, publication
purposes or any purpose other than as provided in the Development Plan (a "New
Development Activity"), such Party must submit its proposed development plan for
such New Development Activity, including, without limitation the proposed budget
of all costs thereof, for review and approval by the Joint Steering Committee.

          (b) If the Joint Steering Committee approves the proposed plan and
budget for a New Development Activity (a "Joint New Development Activity"), then
prior to the commencement of any such Joint New Development Activity, the
Parties, through the Joint Project Team, will use Commercially Reasonable
Efforts to draft and agree to a comprehensive development plan and budget for
such Joint New Development Activity that are consistent with the proposed
development plan that was provided to the Joint Steering Committee as provided
in Section 4.3(a). The Parties acknowledge and agree that (i) each Party will be
responsible for its own internal costs associated with such Joint New
Development Activity; (ii) GSK will only be obligated to pay for those actual
external costs for such Joint New Development Activity that are equal to the
greater of (A) [..**..] of such actual external costs, or (B) if sales have
commenced in both the GSK Territory and the Myogen Territory, [..**..] such
actual external costs [..**..] the gross sales of Product in the Field in the
GSK Territory for the immediately preceding Calendar Year [..**..] the gross
sales of Product in the Field in the Territory for the immediately

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preceding Calendar Year, in each case calculated by the Parties in accordance
with generally accepted accounting principles; and (iii) Myogen will be
obligated to pay for all actual external costs for such Joint New Development
Activity which GSK is not obligated to pay for as provided in (ii) above. The
Parties will conduct any Joint New Development Activity in accordance with the
development plan, the budget prepared as provided in this Section 4.3(b) and the
terms and conditions of this Agreement, and as directed by the Joint Project
Team and Joint Steering Committee.

          (c) If the Joint Steering Committee does not approve the proposed plan
and/or budget for a New Development Activity and Myogen nonetheless desires to
conduct such New Development Activity (a "Myogen Sponsored New Development
Activity"), Myogen may conduct such Myogen Sponsored New Development Activity
only within the Myogen Territory; provided, however that Myogen may conduct
clinical/non-clinical activities relating to such Myogen Sponsored New
Development Activity in the GSK Territory upon obtaining GSK's prior written
consent, which will not be unreasonably withheld. Prior to conducting such
Myogen Sponsored New Development Activity, Myogen will draft a comprehensive
development plan and budget for such Myogen Sponsored New Development Activity
that is consistent with the proposed development plan submitted to the Joint
Steering Committee as provided in Section 4.3(b), which will be presented to the
Joint Project Team for review and comment. Myogen will conduct any such Myogen
New Development Activity in accordance with the development plan and budget
prepared as provided in this Section 4.3(c), the terms and conditions of this
Agreement. Myogen will be solely responsible for conducting, and paying all
costs and expenses related to, a Myogen Sponsored New Development Activity. Upon
Myogen's completion of a Myogen Sponsored New Development Activity, Myogen will
provide GSK with access to any and all Development Information generated by or
on behalf of Myogen during such Myogen Sponsored New Development Activity, all
of which Development Information may be used by or on behalf of GSK in the
Development, Manufacture and/or Commercialization of Compound and/or Product in
the Field in the GSK Territory, including, without limitation, in the
preparation, submission, filing, prosecution and maintenance of Regulatory
Approvals for Product in the Field in the GSK Territory; provided, however, that
GSK first pays to Myogen an amount equal to what GSK's funding contribution
would have been as provided in Section 4.3(b)(i) had the Joint Steering
Committee approved such New Development Activity, plus [..**..] of such amount.

          (d) If the Joint Steering Committee does not approve the proposed plan
and/or budget for a New Development Activity and GSK nonetheless desires to
conduct such New Development Activity (a "GSK Sponsored New Development
Activity"), GSK may conduct such GSK Sponsored New Development Activity only
within the GSK Territory; provided, however that GSK may conduct
clinical/non-clinical activities relating to such GSK Sponsored New Development
Activity in the Myogen Territory only upon obtaining Myogen's prior written
consent, which will not be unreasonably withheld. Prior to conducting such GSK
Sponsored New Development Activity, GSK will draft a comprehensive development
plan and budget for such GSK Sponsored New Development Activity that is
consistent with the proposed development plan submitted to the Joint Steering
Committee as provided in Section 4.3(b), which will be presented to the Joint
Project Team for review and comment. GSK will conduct any such GSK New
Development Activity in accordance with the development plan and budget

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prepared as provided in this Section 4.3(d), the terms and conditions of this
Agreement. GSK will be solely responsible for conducting, and paying all costs
and expenses related to, a GSK Sponsored New Development Activity. Upon GSK's
completion of a GSK Sponsored New Development Activity, GSK will provide Myogen
with access to any and all Development Information generated by or on behalf of
GSK during such GSK Sponsored New Development Activity, all of which Development
Information may be used by or on behalf of Myogen in the Development,
Manufacture and/or Commercialization of Compound and/or Product in the Field in
the Myogen Territory, including, without limitation, in the preparation,
submission, filing, prosecution and maintenance of Regulatory Approvals for
Product in the Field in the Myogen Territory; provided, however that Myogen
first pays to GSK an amount equal to what Myogen's funding contribution would
have been as provided in Section 4.3(b)(ii) had the Joint Steering Committee
approved such New Development Activity, plus [..**..] of such amount.

     Section 4.4 Regulatory Approvals.

          (a) Subject to Section 6.4, GSK will, in accordance with the
Development Plan and as directed by the Joint Project Team, be solely
responsible for at its sole expense, using Commercially Reasonable Efforts, for
the preparation, submission, filing, prosecution and maintenance, in its own
name or in the name of any of its Affiliates or sublicensees, of all Regulatory
Approvals for Compound and Product in the Field in the GSK Territory.

          (b) Myogen will, in accordance with the Development Plan and as
directed by the Joint Project Team, be solely responsible for, at its sole
expense, the preparation, submission, filing, prosecution and maintenance, in
its own name or in the name of any of its Affiliates or sublicensees, of all
Regulatory Approvals for Compound and Product in the Field in the Myogen
Territory.

          (c) Notwithstanding the foregoing, each Party agrees and acknowledges
that it will, as reasonably requested by the other Party from time to time
during the Term, assist the other Party with the preparation of the Common
Technical Document. Further, Myogen will, as reasonably requested by GSK from
time to time during the Term, (i) assist GSK with the preparation of responses
to questions by Regulatory Authorities regarding Compound and/or Product in the
Field in the GSK Territory; and (ii) provide support to GSK during the
preparation, filing, prosecution and maintenance of Regulatory Approvals for
Compound and Product in the Field in the GSK Territory, in each case at Myogen's
sole cost and expense; provided, however that the reasonable, documented direct
fees and expenses of any Third Party incurred by Myogen in connection with such
assistance will be [..**..] GSK.

          (d) Except with respect to a Myogen Sponsored New Development
Activity, unless GSK has paid the funding contribution, if required, as set
forth in Section 4.3(c), Myogen will promptly furnish GSK with copies of all
substantive Regulatory Authority outputs relating to the Development of, and/or
filing of Regulatory Approvals for, Compound and/or Product in the Myogen
Territory (including, without limitation, all substantive correspondence with
such Regulatory Authorities, responses from such Regulatory Authorities,
requests for information from such Regulatory Authorities, briefing documents
and other materials relating to interactions with such Regulatory Authorities,
and summaries of outputs resulting from substantive

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correspondence/ conversations or meetings with such Regulatory Authorities).

          (e) Except with respect to a GSK Sponsored New Development Activity,
unless Myogen has paid the funding contribution, if required, as set forth in
Section 4.3(d), GSK will promptly furnish Myogen with copies of all substantive
Regulatory Authority outputs relating to the Development of, and/or filing of
Regulatory Approvals for, Compound and/or Product in the GSK Territory
(including, without limitation, all substantive correspondence with such
Regulatory Authorities, responses from such Regulatory Authorities, requests for
information from such Regulatory Authorities, briefing documents and other
materials relating to interactions with such Regulatory Authorities, and
summaries of outputs resulting from substantive correspondence/ conversations or
meetings with such Regulatory Authorities).

                                    ARTICLE V

                                COMMERCIALIZATION

     Section 5.1 Global Marketing Plan. As directed by the Joint Steering
Committee, the Global Brand Team will draft the initial Global Marketing Plan
and submit the initial Global Marketing Plan to the Joint Steering Committee for
review and approval. Thereafter, not later than sixty (60) Business Days prior
to the end of each Calendar Year during the Term, the Global Brand Team will
update the Global Marketing Plan as required and submit the updated Global
Marketing Plan for review and approval by the Joint Steering Committee.

     Section 5.2 Commercialization of Product in the GSK Territory.

          (a) (i) GSK will have full control, authority and responsibility for
the Commercialization of Product in the Field in the GSK Territory. Subject to
Section 6.4, GSK will exercise its Commercially Reasonable Efforts in
Commercializing Product in countries of the GSK Territory where it has obtained
Regulatory Approval in a manner consistent with this Agreement and the Global
Marketing Plan, and, with respect to the Major Countries and Major European
Market Countries only, as directed by the Global Brand Team. Notwithstanding
anything in this Section 5.2(a) or in this Agreement to the contrary, GSK will
have final decision-making authority, in its sole discretion, relating to the
Commercialization of Product in the Field in the GSK Territory, including,
without limitation, pricing and reimbursement for Product (as provided in
Section 5.2(c)), Product advertising and promotional materials, Product
packaging, sales force training and all interactions with Regulatory Authorities
regarding the Commercialization of Product in the Field; provided, however that
any such decisions of GSK relating to the Commercialization of Product in the
Field in the GSK Territory, to the extent not required by a Regulatory Authority
or under Applicable Law, will not be inconsistent with the Global Marketing Plan
or the terms of this Agreement, and will not materially and adversely affect
Myogen's Development, Manufacture and/or Commercialization of Product in the
Field in the Myogen Territory, or subject to Section 2.3, Myogen's retained
right to make, have made, use, sell, offer for sale and/or import Product
outside of the Field in the GSK Territory.

               (ii) If, at any time during the Term, Myogen reasonably believes
that

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GSK has failed to use Commercially Reasonable Efforts in Commercializing Product
in a country in the GSK Territory as set forth in Section 5.2(a)(i), Myogen may
(A) with respect to any Major Country or Major European Market Country, exercise
its rights under Section 6.2, and (B) with respect to any country other than a
Major Country or Major European Market Country, exercise its rights under
Section 11.2 to terminate this Agreement but only with respect to such affected
country and in such an event, such terminated country will be removed from the
GSK Territory and included within the Myogen Territory and the provisions
contained in Section 11.9(a) shall apply to such termination.

          (b) GSK will book all sales of Product in the Field in the GSK
Territory and will warehouse and distribute the Product in the Field in the GSK
Territory; provided, however, that GSK will be permitted to warehouse Product in
the Field in the Myogen Territory if such Product has been Manufactured by or on
behalf of GSK in the Myogen Territory. If Myogen receives any orders for Product
for sale in the Field in the GSK Territory, it will refer such orders to GSK. If
Product sold in the Field in the GSK Territory is returned to Myogen, Myogen
will promptly ship such returned Product to a facility designated by GSK.

          (c) Subject to the terms of this Agreement, including, without
limitation, Section 6.4, and the Global Marketing Plan, (i) GSK will be solely
responsible for, using Commercially Reasonable Efforts, all pricing and
reimbursement approval proceedings relating to the Product in the Field in the
GSK Territory, and (ii) GSK will have complete discretion in setting pricing for
the Product in the Field in the GSK Territory. GSK will be responsible for
filing and maintenance fees relating to pricing and reimbursement approvals.

          (d) (i) Subject to Applicable Law and the Global Marketing Plan, GSK
will, in its sole discretion, determine and select all trademarks, tradenames,
copyrights, logos (collectively, "GSK Marks"), used in connection with Product
in the Field in the GSK Territory and will, as part of GSK's annual updates to
the Global Marketing Plan, keep Myogen informed of GSK's plans with respect to
existing and planned GSK Marks. For the avoidance of doubt, the term "GSK Marks"
will in no way be deemed to include the Myogen Trademarks.

               (ii) Myogen hereby grants to GSK an exclusive, royalty free
license, with the right to grant sublicenses, to use the Myogen Trademarks to
Develop, Manufacture and Commercialize Compound and/or Product in the Field in
the GSK Territory during the Term. GSK will use the Myogen Trademarks solely
with respect to the Development, Manufacture and/or Commercialization of
Compound and/or Product in the Field and in accordance with the standards of
quality established or approved in writing by Myogen and provided to GSK.
Whenever GSK uses the Myogen Trademarks in any manner in connection with
Product, Myogen will clearly indicate that the Myogen Trademarks are owned by
Myogen. When using the Myogen Trademarks under this Agreement, GSK will comply
with all Applicable Law pertaining to the Myogen Trademarks in force at any time
in the GSK Territory. During the Term, GSK will provide Myogen with copies of
promotional materials on a periodic basis, as requested by Myogen, for review of
the use of the Myogen Trademarks by GSK. GSK will use Commercially Reasonable
Efforts to promptly take any and all actions directed by Myogen with respect to
GSK's use of the Myogen Trademarks that are reasonably designed to ensure
compliance with the provisions of this Section 5.2(d)(ii).

[..**..] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED
BY BRACKETS, HAS BEEN OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
EXCHANGE COMMISSION PURSUANT TO RULE 24B-2 OF THE SECURITIES EXCHANGE ACT OF
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                    (A) GSK acknowledges and agrees that Myogen and/or its
Affiliates, is, and at all times will remain the owner of the Myogen Trademarks.
GSK will not at any time do, cause to be done, or permit any of its employees,
agents, contractors and subcontractors to commit any act inconsistent with,
contesting or in any way impairing, or tending to impair, such ownership. GSK
agrees that all use of the Myogen Trademarks by GSK will inure to the benefit of
and be on behalf of Myogen or Myogen's Affiliates. GSK acknowledges that nothing
in this Agreement will give GSK any right, title or interest in the Myogen
Trademarks other than the right to use the Myogen Trademarks within the GSK
Territory in accordance with this Agreement. GSK agrees that it will not
challenge Myogen's or Myogen's Affiliates' title to, or ownership of, the Myogen
Trademarks, or attack or contest the validity of the Myogen Trademarks. All
goodwill accruing to the Myogen Trademarks as a result of the use of the Myogen
Trademarks in the performance of this Agreement will belong solely to Myogen or
Myogen's Affiliates. In the event that GSK acquires any rights in the Myogen
Trademarks in connection with GSK's activities pursuant to this Agreement, GSK
will assign, and hereby does assign, to Myogen or Myogen's Affiliates all such
rights, including any related goodwill.

                    (B) GSK is limited to using the Myogen Trademarks in
connection with the Internet as follows:

                         (1) the use must be in compliance with local rules
regarding advertising of pharmaceuticals on the Internet;

                         (2) the use of any Myogen Trademarks as a domain name
is limited to the relevant country code domain within the GSK Territory. No
license is granted to use the ".com generic code domain" or any other such
top-level domain. All domain names containing the Myogen Trademark will be
registered and maintained by and in the name of Myogen or its designee;

                         (3) the use of any Myogen Trademarks as a domain name
is limited to use on websites with universal resource locaters using the
relevant country code domain within the GSK Territory and aimed at audiences in
those countries in the GSK Territory;

                         (4) appropriate disclaimers must be included in any
website to the effect that it is intended for residents in that country within
the GSK Territory only; and

                         (5) in using any of the Myogen Trademarks as a domain
name or on the Internet, GSK will not have and will not represent in any way
that it has any title or right to the ownership or registration or their use,
except as provided in this Agreement. GSK will at all times indicate that each
of the Trademarks is a trademark of Myogen and is used under license.

          (e) Upon GSK's request, the Parties will, through the Global Brand
Team and

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in the Global Marketing Plan, use good faith efforts to negotiate ways in which
Myogen may assist GSK in the Commercialization of Product in the Field in the
GSK Territory during the Term at no cost or expense to GSK except as agreed in
advance to defer the incremental cost of such efforts to Myogen.

     Section 5.3 Commercialization of Product in the Myogen Territory.

          (a) Myogen will have full control, authority and responsibility for
the Commercialization of Product in the Myogen Territory. Myogen will exercise
its Commercially Reasonable Efforts in Commercializing Product in countries of
the Myogen Territory where it has obtained Regulatory Approval in a manner
consistent with this Agreement and the Global Marketing Plan, and as directed by
the Global Brand Team. Notwithstanding anything in this Section 5.3(a) or in
this Agreement to the contrary, Myogen will have final decision-making
authority, in its sole discretion, relating to the Commercialization of Product
in the Myogen Territory, including, without limitation, pricing and
reimbursement for Product, Product advertising and promotional materials,
Product packaging, sales force training and all interactions with Regulatory
Authorities regarding the Commercialization of Product in the Field; provided,
however that any such decisions of Myogen relating to the Commercialization of
Product in the Field in the Myogen Territory, to the extent not required by a
Regulatory Authority or under Applicable Law, will not be inconsistent with the
Global Marketing Plan or the terms of this Agreement, and will not materially
and adversely affect GSK's Development, Manufacture and/or Commercialization of
Product in the Field in the GSK Territory.

          (b) Myogen will book all sales of Product in the Myogen Territory and
will warehouse and distribute the Product in the Myogen Territory; provided,
however, that Myogen will be permitted to warehouse Product in the GSK Territory
if such Product has been Manufactured by or on behalf of Myogen in the GSK
Territory. If GSK receives any orders for Product for sale in the Myogen
Territory, it will refer such orders to Myogen. If Product sold in the Myogen
Territory is returned to GSK, GSK will promptly ship such returned Product to a
facility designated by Myogen.

          (c) Subject to the terms of this Agreement and the Global Marketing
Plan, (i) Myogen will be solely responsible for, using Commercially Reasonable
Efforts, all pricing and reimbursement approval proceedings relating to the
Product in the Myogen Territory, and (ii) Myogen will have complete discretion
in setting pricing for the Product in the Myogen Territory. Myogen will be
responsible for filing and maintenance fees relating to pricing and
reimbursement approvals.

          (d) Subject to Applicable Law and the Global Marketing Plan, Myogen
will, in its sole discretion, determine and select all trademarks, tradenames,
copyrights, logos (collectively, the "Myogen Marks"), used in connection with
Product in the Myogen Territory and will, as part of Myogen's annual updates to
the Global Marketing Plan, keep GSK informed of Myogen's plans with respect to
existing and planned Myogen Marks.

          (e) Upon Myogen's request, the Parties will, through the Global Brand
Team and in the Global Marketing Plan, use good faith efforts to negotiate ways
in which GSK may

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assist Myogen in the Commercialization of Product in the Field in the Myogen
Territory during the Term at no cost or expense to Myogen except as agreed in
advance to defer the incremental cost of such efforts to GSK.

     Section 5.4 Product Flow Outside of Territory. Subject to Applicable Law,
each Party will implement reasonable safeguards so that country-specific Product
is sold only in such Party's respective Territory and is not sold in any country
outside such Party's respective Territory. Subject to Applicable Law, each Party
will sell Product only in its respective Territory and will not, directly or
indirectly, offer Product to any Third Party that such Party reasonably believes
is going to Commercialize such Product, directly or indirectly, outside such
Territory, unless mutually agreed in writing upon by both Parties. If a Party
becomes aware that any of its customers has imported Product from outside its
respective Territory or exported Product to outside its respective Territory, or
has reason to believe that a customer intends to import Product from outside its
respective Territory or exported Product to outside its respective Territory,
such Party, to the extent permitted under Applicable Law will take Commercially
Reasonable Efforts to cause such customer to cease such illegal import/export
activities; provided, however, that nothing contained in this Section 5.4 will
obligate GSK to take any action to comply with this Section 5.4 which is greater
than that taken with respect to other pharmaceutical products of GSK prior to
the Effective Date. Further, the Parties acknowledge and agree that this Section
5.4 will not apply to Myogen's Commercialization of Product outside of the Field
in the GSK Territory.

                                   ARTICLE VI

                                    DILIGENCE

     Section 6.1 Failure by GSK to Use Diligence. If at any time during the
Term, Myogen reasonably believes that GSK has (i) breached one or more of its
obligations to Myogen pursuant to Section 6.3 or (ii) failed to use Commercially
Reasonable Efforts in (A) preparing and filing Regulatory Approvals for Product
in the Field in any Major Country or Major European Market Country as provided
in Section 4.4(a), and/or (B) Commercializing Product in the Field in any Major
Country or Major European Market Country as provided in Sections 5.2(a) and (b),
and Myogen reasonably believes that Product in the Field is commercially viable
in such Major Country or Major European Market Country, then Myogen will have
the right to provide GSK with written notice that Myogen intends to assume
responsibility for the Development and Commercialization of Product in the Field
in such Major Country or Major European Market Country (the "Assumption of
Responsibility Notice").

     Section 6.2 Opportunity to Remedy Diligence Failure.

          (a) Subject to Section 6.4, if GSK does not, during the [..**..]
period immediately after the date of such Assumption of Responsibility Notice,
commence using Commercially Reasonable Efforts to prepare and file Regulatory
Approvals for Product in the Field as provided in Section 4.4(a) and/or to
Commercialize Product in the Field as provided in Section 5.2(a)(i), in each
case in the Major Country or Major European Market Country that is

[..**..] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED
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the subject of an Assumption of Responsibility Notice or otherwise notifies
Myogen in writing that GSK does not intend to take such action, then unless
otherwise agreed to by Myogen in writing, GSK's right under the Abbott
Intellectual Property and Myogen Intellectual Property as set forth in Section
2.1(a) to Develop and Commercialize Product in the Field in such Major Country
or Major European Market Country will immediately terminate (without application
of any cure period specified in Section 11.2), and such Major Country or Major
European Market Country will be removed from the GSK Territory and included
within the Myogen Territory and the provisions contained in Section 11.9(a)
shall apply to such termination.

          (b) Subject to Section 6.4, if GSK does not, during the [..**..]
period immediately after the date of such Assumption of Responsibility Notice,
commence using Commercially Reasonable Efforts to conduct the activities set
forth in Section 6.3 in a Major Country or Major European Market Country, as
applicable therein, that is the subject of an Assumption of Responsibility
Notice, or otherwise notifies Myogen in writing that GSK does not intend to take
such action, then unless otherwise agreed to by Myogen in writing, GSK's right
under the Abbott Intellectual Property and Myogen Intellectual Property as set
forth in Section 2.1(a) to Develop and Commercialize Product in the Field in
such Major Country or Major European Market Country will immediately terminate
(without application of any cure period specified in Section 11.2), and such
Major Country or Major European Market Country will be removed from the GSK
Territory and included within the Myogen Territory and the provisions contained
in Section 11.9(a) shall apply to such termination.

     Section 6.3 Specific Objectives. Without limiting the generality of the
GSK's obligations under Section 6.1, GSK shall fulfill the following Development
and Commercialization obligations in order to maintain its rights in a Major
Country or Major European Market Country, as applicable:

          (a) Subject to the generation of a Common Technical Document which, as
reasonably determined by GSK, is fully satisfactory to meeting the regulatory
requirements in the European Union, the cooperation of Myogen as provided in
Section 4.4(c) and Myogen's compliance with Section 7.2, GSK shall submit to the
EMEA a MAA for the Product as promptly as practicable but in no event more than
[..**..] after submission of the first (1st) NDA relating to Product for the
palliation and/or treatment of PAH, unless otherwise agreed to by the Parties.

          (b) Within [..**..] after the submission of the first (1st) NDA
relating to Product for the palliation and/or treatment of PAH, unless otherwise
agreed to by the Parties, GSK will file for Regulatory Approval for the Product
in each Major Country, so long as such registration and future Commercialization
of Product in such Major Country do not present the reasonable potential to
substantially damage the commercial potential of the Product in larger markets
in the GSK Territory for reasons including, but not limited to, reference
pricing or parallel importation; provided, however, that with respect to Japan,
GSK will submit to the MHLW a JNDA for the Product within the earlier of (x)
[..**..] after the completion of all studies required for Regulatory Approval in
Japan, or (y) subject to the cooperation of Myogen as provided in Section 4.4(c)
and Myogen's compliance with Section 7.2, [..**..] after submission of the first
(1st) NDA relating to a Product for the palliation and/or treatment of PAH,

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unless otherwise agreed to by the Parties.

          (c) GSK shall achieve First Commercial Sale in each Major Country and
Major European Market Country in which it obtains Regulatory Approval and
pricing and reimbursement approval (which is commercially acceptable to GSK) for
the Product not later than [..**..] after the date on which such Regulatory
Approval is granted and pricing and reimbursement approval is obtained.

          (d) During the [..**..] Calendar Years after the First Commercial Sale
in a Major European Market Country, GSK shall conduct at least [..**..] of the
activities prescribed in the mutually agreed Marketing Plan for advertising,
promotion, marketing, professional education and sales efforts for the Product
in the Field in each Major European Market Country; provided, however, that GSK
shall spend on such activities an amount that is not less than [..**..] of the
Net Sales for the prior Calendar Year in such Major European Market Country, or
in the absence of sales history, an amount that is not less than [..**..] of the
applicable budgeted Net Sales projection for such Major European Market Country.
Notwithstanding anything contained herein to the contrary, the obligations set
forth in this Section 6.3(d) will continue in the [..**..] Calendar Year after
the First Commercial Sale in a Major European Market Country if GSK receives an
Assumption of Responsibility Notice due to an alleged breach of its obligations
under this Section 6.3(d) in the [..**..] Calendar Year after the First
Commercial Sale in a Major European Market Country.

          (e) During the [..**..] Calendar Years after the First Commercial Sale
in a Major Country, GSK shall conduct at least [..**..] of the activities
prescribed in the mutually agreed Marketing Plan for advertising, promotion,
marketing, professional education and sales efforts for the Product in the Field
in each Major Country. Notwithstanding anything contained herein to the
contrary, the obligations set forth in this Section 6.3(e) will continue in the
[..**..] Calendar Year after the First Commercial Sale in a Major Country if GSK
receives an Assumption of Responsibility Notice due to an alleged breach of its
obligations under this Section 6.3(e) in the [..**..] Calendar Year after the
First Commercial Sale in a Major Country.

          (f) During the [..**..] Calendar Years after the First Commercial Sale
in a country included in the Major Countries or Major European Market Countries,
GSK shall use Commercially Reasonable Efforts to attend and market the Product
in the Field at appropriate major scientific congresses and similar meetings in
the Major Countries and Major European Market Countries. Notwithstanding
anything contained herein to the contrary, the obligations set forth in this
Section 6.3(f) will continue in the [..**..] Calendar Year after the First
Commercial Sale in a country included in the Major Countries or Major European
Market Countries if GSK receives an Assumption of Responsibility Notice due to
an alleged breach of its obligations under this Section 6.3(f) in the [..**..]
Calendar Year after the First Commercial Sale in a country in the Major
Countries or Major European Market Countries.

     Section 6.4 Superseding Events. Notwithstanding anything contained in this
Article VI, GSK will not be deemed to have failed to use Commercially Reasonable
Efforts as provided in Sections 4.4(a), 5.2(a) or 5.2(c), or failed to have
complied with its obligations under

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Section 6.3, to the extent that any such failure is caused in whole or in part
to any of the following: (i) any act or omission of Myogen or any of its
Affiliates; (ii) a request from, or other action of, any Regulatory Authority of
competent jurisdiction; (iii) a substantial change in any Applicable Law; (iv)
the institution of a lawsuit by a Third Party against GSK and/or any of its
Affiliates or sublicensees relating to any of the activities set forth in
Sections 4.4(a), 5.2(a), 5.2(c) and/or 6.3, which lawsuit GSK (or its Affiliate
or sublicensee, as applicable) has reasonably determined in good faith will have
a significant adverse financial affect on GSK's business in a Major Country
and/or Major European Market Country (provided that GSK is exercising good faith
efforts to resolve the lawsuit, or if GSK elects not to do so, GSK exercises its
termination rights pursuant to Section 11.7 with respect to the affected
countries); (v) the grant of a temporary or permanent injunction or other
similar action against GSK and/or any of its Affiliates or sublicensees by a
court of competent jurisdiction prohibiting or restraining GSK and/or any of its
Affiliates or sublicensees from conducting any of the activities set forth in
Sections 4.4(a), 5.2(a), 5.2(c) or 6.3 in a Major Country and/or Major European
Market Country; (vi) the inability of GSK or its Affiliates or sublicensees to
Manufacture and/or have Manufactured sufficient clinical or commercial
quantities of Product reasonably required by GSK or its Affiliates or
sublicensees to conduct the activities set forth in Sections 4.5(a), 5.2(a)
and/or 5.2(b), despite GSK or its Affiliates or Third Parties using Commercially
Reasonable Efforts (including, without limitation, purchasing Product from
Myogen or its suppliers on commercially reasonable terms); or (vii) a Force
Majeure Event experienced by GSK and/or any of its Affiliates, sublicensees or
Third party manufacturers which relates to the Development, Manufacture and/or
Commercialization of Product in the Field.

     Section 6.5 Abbott Agreement. Notwithstanding anything to the contrary in
this Article VI, the Parties acknowledge that pursuant to Section 4.4(a) of the
Abbott Agreement, Abbott's expectation is that the Product will be
commercialized in all commercially viable markets including the Major European
Market Countries and Japan within [..**..] after First Commercial Sale of the
Product in the Territory. Accordingly, if following such [..**..] period, Myogen
receives notice from Abbott that there remain markets within the GSK Territory
where the Product is not being Commercialized, which Abbott, in its reasonable
estimation, believes are commercially viable, Myogen shall within two (2)
Business Days provide GSK with a copy of such notice received from Abbott.
Myogen, GSK and Abbott shall meet within thirty (30) calendar days of Abbott's
notice to Myogen for the purpose of developing a mutually agreeable action plan
for such under-served markets. If GSK disagrees with Abbott's position that
commercially reasonable efforts have not been made in a particular country in a
Major European Market Country or Japan, or if GSK disagrees with Abbott's
position concerning whether a market that is not a Major European Market Country
or Japan is commercially viable or if GSK reasonably believes that Abbott's
selling of Product in a particular country in the GSK Territory will have a
substantial negative impact on GSK's local, regional or global commercial
efforts, then in each case Myogen will, at GSK's request, exercise Myogen's
right to submit the matter to alternative dispute resolution pursuant to
Sections 4.4(b) or 4.4(c), as applicable, under the Abbott Agreement at GSK's
sole cost and expense. In the event that Myogen, pursuant to the request of GSK,
exercises its right to submit any matter to alternative dispute resolution as
set forth in this Section 6.5, Myogen will permit GSK to assume direction and
control of such alternative dispute resolution proceedings at GSK's sole cost
and expense. If GSK and Abbott are unable to agree on an action plan for such
alleged under-served market and GSK does not

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request Myogen to submit any matter to alternative dispute resolution as
provided in this Section 6.5, or if directed by the decision of an arbitrator,
unless otherwise agreed by Myogen and Abbott in writing, GSK's rights under the
Abbott Intellectual Property and Myogen Intellectual Property as set forth in
Section 2.1(a) to Develop and Commercialize Product in the Field will
immediately terminate as to such country only, such country will be removed from
the GSK Territory and included within the Myogen Territory and the provisions
contained in Section 11.9(a) shall apply to such termination.

                                   ARTICLE VII

                       MANUFACTURING AND KNOW-HOW TRANSFER

     Section 7.1 Manufacture of Product.

          (a) Myogen will be solely responsible for the Manufacture of Compound
and/or Product that will be Commercialized in the Myogen Territory.

          (b) GSK will be solely responsible for the Manufacture of Compound
and/or Product that will be Commercialized in the GSK Territory.

          (c) Notwithstanding anything in this Section 7.1 to the contrary,
Myogen will, at its sole cost and expense, in accordance with the Development
Plan and as directed by the Joint Project Team, be solely responsible for
conducting or arranging for the conducting of all validation plan activities
with respect to the Manufacture of Compound and Product during the consecutive
[..**..] period immediately after the Effective Date. Further, Myogen will, at
its sole cost and expense, be solely responsible for ensuring that Product used
in all Development activities described in Sections 4.2 are suitable for such
use in the United States, Canada and the European Economic Area.

          (d) The Parties will work together in good faith to establish a
mutually acceptable supply chain for the Manufacture of Compound and/or Product;
provided, however, that neither Party will be obligated to use the same supply
chain or to enter into joint contractual arrangements with one another or Third
Parties relating to the Manufacture of Compound and/or Product.

          (e) Upon the reasonable request of GSK, Myogen will use Commercially
Reasonable Efforts to supply to GSK or its designees such quantities of Compound
and/or Product which GSK or its designee may reasonably require in order to
commence setting up a supply chain for the Manufacture of Compound and/or
Product and at a price [..**..].

          (f) Upon the reasonable request of GSK during the consecutive twelve
(12) month period immediately after the Effective Date, Myogen will use
Commercially Reasonable Efforts to supply GSK or its designees such quantities
of Compound and/or Product which GSK or its designee may reasonably require in
order to Develop Product in the Field in the GSK Territory, which Compound
and/or Product will be supplied by Myogen at a price that is [..**..]

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BY BRACKETS, HAS BEEN OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
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Myogen's reasonable and documented internal costs and the documented, direct
fees and expenses of any Third Party, which in each case are incurred by Myogen
and directly relate to Myogen's supply of Compound and/or Product.

          (g) Upon the reasonable request of either Party, the other Party will
use Commercially Reasonable Efforts to provide the requesting Party or its
designees such quantities of Compound and/or Product which the requesting Party
or its designees may reasonably require in the event of a supply disruption due
to any reason, and at a price [..**..].

          (h) Notwithstanding anything in this Section 7.1 to the contrary,
Myogen acknowledges and agrees that, upon terms and conditions of a supply
agreement and other ancillary agreements (including, without limitation, a
quality agreement) (collectively, the "Supply Agreement") which Supply Agreement
will be agreed to by the Parties in good faith and executed within sixty (60)
Business Days after the Effective Date, it will Manufacture or arrange for the
Manufacture of Product for use by GSK or its Affiliates in the Development of
Compound and/or Product in the Field in Japan at GSK's sole cost and expense.
Such Supply Agreement will include, without limitation, that Compound and/or
Product will be manufactured in accordance with Japan Good Manufacturing
Practices, and that such Compound and/or Product will be supplied by Myogen at a
price that is [..**..] Myogen's reasonable and documented internal costs and the
documented, direct fees and expenses of any Third Party, which in each case are
incurred by Myogen and directly relate to Myogen's supply of Compound and/or
Product.

     Section 7.2 Know-How Transfer.

          (a) As soon as reasonably practicable, but in no event more than sixty
(60) Business Days after the Effective Date or as otherwise agreed to by the
Parties in writing, Myogen will disclose and supply to GSK all Abbott Know-How
and Myogen Know-How existing as of the Effective Date, to the extent that it has
not already been provided to GSK prior to or on the Effective Date, including,
without limitation, all Know-How relating to the Manufacture of Compound drug
substance.

          (b) From time to time during the Term after the initial transfer as
set forth in Section 7.2(a) or as may be reasonably requested by GSK, Myogen
will promptly disclose and supply GSK with any updates or additions to Abbott
Know-How and Myogen Know-How.

          (c) From time to time during the Term or as may be reasonably
requested by Myogen, GSK will promptly disclose and supply Myogen with the GSK
Know-How and any updates or additions thereto.

          (d) From time to time during the Term or as may be reasonably
requested by GSK, Myogen will, at no cost or expense to GSK (other than the
reasonable, documented and direct costs and expenses of Third Parties actually
incurred by Myogen, which will be paid for by GSK) and to the extent that it has
a right to do so, promptly disclose and provide GSK with information or access
to information (other than Myogen Know-How) that may be useful for the
Development, Manufacture and/or Commercialization of Product in the Field in the
Territory.

[..**..] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED
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          (e) Myogen will, or will cause its Third Party contract manufacturer
to, at no cost or expense to GSK (other than the reasonable, documented and
direct costs and expenses of Third Parties actually incurred by Myogen, which
will be paid for by GSK), provide to GSK or its Affiliate or Third Party
contract manufacturer, technical transfer support as reasonably requested by GSK
in order for GSK to commence setting up a supply chain for the Manufacture of
Compound and/or Product.

                                  ARTICLE VIII

                               RECALLS AND SAFETY

     Section 8.1 Recalls, Market Withdrawals or Corrective Actions.

          (a) If any Regulatory Authority issues or requests a recall or takes a
similar action in connection with the Product in the Field in the GSK Territory,
or if GSK determines that an event, incident or circumstance has occurred that
may result in the need for a recall or market withdrawal of Product in the Field
in the GSK Territory, GSK will, within twenty-four (24) hours, notify Myogen
thereof by telephone or facsimile and use Commercially Reasonable Efforts to
discuss such event, incident or circumstance with Myogen in order to jointly
determine the appropriate course of action (except in the case of a recall
mandated by a Regulatory Authority, in which case GSK may act without such
advance notice but, will notify Myogen as soon as possible), and shall provide
to Myogen copies of all relevant correspondence, notices and the like. Subject
to the foregoing sentence, GSK will retain ultimate responsibility for deciding
whether to conduct a recall of Product in the Field in the GSK Territory and the
manner in which any such recall will be conducted. Myogen will make available to
GSK, upon request, all of Myogen's pertinent records that GSK may reasonably
request to assist GSK in effecting any recall. GSK will bear the expense of any
such recall except to the extent such recall was caused in whole or in part by
an act or omission of Myogen, in which case Myogen will provide such reasonable
assistance as is requested by GSK with respect to such recall and bear the
expense of any such assistance.

          (b) If any Regulatory Authority issues or requests a recall or takes a
similar action in connection with the Product outside of the Field or in the
Myogen Territory, or if Myogen determines that an event, incident or
circumstance has occurred that may result in the need for a recall or market
withdrawal of Product outside of the Field or in the Myogen Territory, Myogen
will, within twenty-four (24) hours, notify GSK thereof by telephone or
facsimile and use Commercially Reasonable Efforts to discuss such event,
incident or ciurcumstance with GSK in order to jointly determine the appropriate
course of action (except in the case of a recall mandated by a Regulatory
Authority, in which case Myogen may act without such advance notice but, will
notify GSK as soon as possible), and shall provide to GSK copies of all relevant
correspondence, notices and the like. Subject to the foregoing sentence, Myogen
will retain ultimate responsibility for deciding whether to conduct a recall of
Product outside of the Field or in the Myogen Territory, and the manner in which
any such recall will be conducted. GSK will make available to Myogen, upon
request, all of GSK's pertinent records that Myogen

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


                                       37

<PAGE>

may reasonably request to assist Myogen in effecting any recall. Myogen will
bear the expense of any such recall unless such recall was caused in whole or in
part by an act or omission of GSK, in which case GSK will provide such
reasonable assistance as is requested by Myogen with respect to such recall and
bear the expense of any such assistance.

     Section 8.2 Pharmacovigilance. The procedures for sharing and reporting of
Adverse Events and Serious Adverse Events encountered by each Party relating to
or associated in any way with the Development, Manufacture and/or
Commercialization of Compound and Product whether in or outside of the Field in
the Territory, which procedures will be no less stringent that those set forth
in the applicable guidelines of the ICH and will be sufficient to allow each
Party to satisfy both expedited and periodic regulatory reporting requirements,
will be as set forth in a Safety Data Exchange Agreement to be finalized and
exchanged by the Parties after the Effective Date as determined by the Joint
Project Team. For the purposes of this Agreement, the terms "Adverse Event" and
"Serious Adverse Event" will have the meanings ascribed to them in the Safety
Data Exchange Agreement.

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


                                       38

<PAGE>

                                   ARTICLE IX

                                  CONSIDERATION

     Section 9.1 Milestones.

          (a) Milestone Payments. In consideration for the licenses and
sublicenses granted to GSK by Myogen in this Agreement, GSK will make the
following milestone payments (the "Milestone Payments") to Myogen in the
incremental amounts and in the manner specified below, which Milestone Payments
will not exceed an aggregate of One Hundred Million U.S. Dollars (U.S.
$100,000,000.00), upon achieving the milestones events specified below
(collectively, the "Milestones"):

<TABLE>
<CAPTION>
Milestones                                     Milestone Payments
----------                                     ------------------
<S>                                            <C>
(i)    Effective Date                          U.S. $20,000,000

(ii)   Delivery of ARIES-1 Data                [..**..]

(iii)  Delivery of a Patient Safety Database
       Pertaining to the ARIES 3 Study         [..**..]

(iv)   EMEA Review of File                     [..**..]

(v)    European Commission Approval            [..**..]

(vi)   Net Sales Equal to U.S. [..**..]        [..**..]

(vii)  Net Sales Equal to U.S. [..**..]        [..**..]

(viii) JNDA Filing with MHLW                   [..**..]

(ix)   MHLW Approval of JNDA                   [..**..]

(x)    Canadian Reimbursement Approval         [..**..]

(xi)   European Commission Approval of
       [..**..] Additional Indication
       or Presentation                         [..**..]

(xii)  European Commission Approval of
       [..**..] Additional Indication
       or Presentation                         [..**..]
</TABLE>

          (b) Milestone Payment Definitions

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


                                       39

<PAGE>

               (i) The phrase "Delivery of ARIES-1 Study Data", as used in
Section 9.1(a)(ii), means the date on which Myogen reports top-line efficacy
results for the primary endpoint with one or more doses of the Product in the
ARIES-1 clinical trial.

               (ii) The phrase "Delivery of a Patient Safety Database Pertaining
to the ARIES 3 Study", as used in Section 9.1(a)(iii), means the date on which
Myogen delivers to GSK a patient safety database containing safety data agreed
upon by the Parties as set forth in the Development Plan [..**..], which data
will include, without limitation, [..**..], and will be derived from a subset of
patients enrolled in the Long Term Expanded Safety Study (ARIES 3). The term
"principal intended indicated population" as used herein means the World Health
Organization (WHO) Group 1 patients per the clinical classification of pulmonary
hypertension (Venice 2003).

               (iii) The phrase "EMEA Review of File", as used in Section
9.1(a)(iv), means the date on which GSK first receives written notice from the
EMEA of acceptance for substantive review of a MAA filed by or on behalf of GSK
for the purpose of obtaining Regulatory Approval to Commercialize Product in the
Field in the European Economic Area.

               (iv) The phrase "European Commission Approval", as used in
Section 9.1(a)(v), means the earlier of (A) [..**..] months following the date
on which GSK receives written notice from the European Commission that it has
approved the MAA filed by or on behalf of GSK to Commercialize Product in the
Field in the European Economic Area with an indication statement similar in all
material respects to the indication statement set forth on Exhibit F, or (B) the
date by which GSK has received written notice of pricing and reimbursement
approval which is commercially acceptable to GSK, from the appropriate
Regulatory Authorities in [..**..] of the Major European Market Countries.

               (v) The phrase "Net Sales Equal to [..**..]", as used in Section
9.1(a)(vi), means the first time Net Sales reach [..**..] U.S. Dollars [..**..]
in the aggregate over a [..**..] period during the Term.

               (vi) The phrase "Net Sales Equal to [..**..]", as used in Section
9.1(a)(vii), means the first time Net Sales reach [..**..] U.S. Dollars [..**..]
in the aggregate over a [..**..] period during the Term.

               (vii) The phrase "JNDA Filing with MHLW", as used in Section
9.1(a)(viii), means the date on which a JNDA that is filed by or on behalf of
GSK, its Affiliates or Sublicensees with the MHLW for the purpose of obtaining
Regulatory Approval to Commercialize Product in the Field in Japan is first
validated for review by the MHLW.

               (viii) The phrase "MHLW Approval of JNDA", as used in Section
9.1(a)(ix), means the date on which GSK has received (A) written notice from the
MHLW that it has approved the JNDA filed by or on behalf of GSK to Commercialize
Product in the Field in Japan and (B) written notice of pricing and
reimbursement approval which is reasonably commercially acceptable to GSK, from
the appropriate Regulatory Authority in Japan.

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


                                       40

<PAGE>

               (ix) The phrase "Canadian Reimbursement Approval", as used in
Section 9.1(a)(x) means the earlier of (A) the date on which GSK has received a
positive Common Drug Review recommendation with respect to the Product
(reasonably in line with then current reimbursement for similar treatments) and
Canadian provincial government formulary coverage in Quebec and Ontario; or (B)
the date on which GSK has received a positive Common Drug Review recommendation
with respect to the Product (reasonably in line with then current reimbursement
for similar treatments) and Canadian provincial government formulary coverage in
[..**..] of the following [..**..] provinces: [..**..].

               (x) The phrase "European Commission Approval of [..**..]
Additional Indication or Presentation", as used in Section 9.1(a)(xi), means the
date on which GSK has received written notice from the European Commission that
it has approved [..**..] Presentation of a Product or [..**..] additional
indication, in each case, in the Field in the European Economic Area, which
approval was supported by data generated from a New Development Activity.

               (xi) The phrase "European Commission Approval of [..**..]
Indication or Presentation", as used in Section 9.1(a)(xii), means the date on
which GSK has received written notice from the European Commission that it has
approved [..**..] Presentation of a Product or [..**..] additional indication,
in each case, in the Field in the European Economic Area, which approval was
supported by data generated from a New Development Activity, and excluding any
Presentation or indication for which a Milestone Payment was previously made
under subsection (a)(xii) above.

          (c) Milestone Payment Provisions

               (i) Each Milestone Payment will be made only one time and only
for the first time that the corresponding Milestone is achieved, regardless of
how many times such Milestone is achieved, and no Milestone Payments will be
owed for a Milestone which is not reached.

               (ii) Subject to Sections 9.4 and 11.9(b)(ii)(B), GSK will remit
payment to Myogen of each Milestone Payment within thirty (30) Business Days
following GSK's receipt of an invoice from Myogen sent after the date on which
such Milestone is achieved, provided that GSK will remit payment to Myogen for
the initial milestone set forth in Section 9.1(a)(i) within five (5) Business
Days following GSK's receipt of an invoice from Myogen sent on or after the
Effective Date.

               (iii) All Milestone Payments will be non-refundable and
non-creditable.

               (iv) All Milestone Payments will be subject to the payment terms
set forth in Section 9.3(c).

     Section 9.2 Royalties.

          (a) Initial Royalty.

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


                                       41
<PAGE>

               (i) Amount. In further consideration for the licenses granted to
GSK by Myogen in this Agreement, including licenses to the Abbott Patent Rights,
Myogen Patent Rights, Abbott Know-How, Myogen Know-How and Myogen Trademarks,
and subject to Sections 9.2(a)(ii), 9.2(c), 9.2(d), 9.3, and 9.4, and
11.9(b)(ii)(B) GSK will pay to Myogen a percentage of Net Sales in each Calendar
Year (the "Initial Royalty") as follows:

<TABLE>
<CAPTION>
 AGGREGATE NET SALES     INCREMENTAL ROYALTY RATE ON
IN THE GSK TERRITORY    AGGREGATE NET SALES IN THE GSK
 IN A CALENDAR YEAR      TERRITORY IN A CALENDAR YEAR
--------------------   -------------------------------
<S>                    <C>
[..**..] to [..**..]               [..**..]

[..**..] to [..**..]               [..**..]

[..**..] to [..**..]               [..**..]

[..**..]                           [..**..]
</TABLE>

For the avoidance of doubt, the Initial Royalty rate is calculated incrementally
on the applicable Net Sales tier, as set forth in the example in Section
9.2(a)(iv) below.

               (ii) Commencement and Expiration.

                    (A) Subject to Section 9.2(a)(ii)(B), GSK's obligation to
pay the Initial Royalty on aggregate Net Sales in the GSK Territory in a
Calendar Year as provided in Section 9.2(a)(i) will commence upon the First
Commercial Sale in the GSK Territory and expire on a country-by-country basis on
the earlier of (a) the date on which the aggregate of Generic Equivalents sold
in such country achieve a prescription market share equal to [..**..] or greater
in the aggregate of the total prescriptions for Product plus its Generic
Equivalent(s) (assessed on a moving annual basis using reference data published
by IMS Health or another industry-accepted source), or (b) the date that is on
the [..**..] anniversary of the First Commercial Sale in such country in the GSK
Territory.

                    (B) Solely in the event that Section 9.2(a)(ii)(A) is deemed
to violate Applicable Law in any country in the GSK Territory, then GSK's
obligation to pay the Initial Royalty on aggregate Net Sales in such country in
a Calendar Year as provided in Section 9.2(a)(i) will continue until the earlier
of (a) such time as the making, use, importation, exportation, marketing,
offering for sale or sale of a Compound and/or Product in such country is no
longer covered by a Valid Claim, (b) the date on which the aggregate of Generic
Equivalents sold in such country achieve a prescription market share equal to
[..**..] or greater in the aggregate of the total prescriptions for Product plus
its Generic Equivalent(s) (assessed on a moving annual basis using reference
data published by IMS Health or another industry-accepted source), or (c) the
date that is on the [..**..] anniversary of the First Commercial Sale in such
country in the GSK Territory. For the purposes of this Section 9.2(a)(ii)(B),
the term "Valid Claim" means a claim of an unexpired patent within the Abbott
Patent Rights or Myogen Patent Rights that has not been withdrawn, canceled or
disclaimed nor held to be invalid or

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


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<PAGE>

unenforceable by a court or government agency of competent jurisdiction in an
unappealed or unappealable decision. Valid Claim shall also include a claim of a
patent within the Abbott Patent Rights or Myogen Patent Rights covering a
Compound or Product that is the subject of (x) any patent term extensions
including any Supplemental Protection Certificates or any equivalent thereof;
and (y) any exclusivity periods afforded by any Regulatory Authority.

               (iii) Royalty to Abbott. For the avoidance of doubt, the Parties
acknowledge and agree that the Initial Royalty payable by GSK to Myogen on Net
Sales as provided in this Section 9.2(a) are inclusive of any royalties or
consideration of any kind owed by Myogen to Abbott under the Abbott Agreement on
sales of Product in the GSK Territory, and that GSK will not owe any additional
consideration to Myogen and/or Abbott on Net Sales in any country in the GSK
Territory in any period during the Term in which GSK is paying the Initial
Royalty.

               (iv) Royalty Calculation Example. For the purposes of example
only with respect to the Initial Royalty calculation set forth in Section
9.2(a)(i), if aggregate Net Sales in the GSK Territory for a Calendar Year are
equal to [..**..] U.S. Dollars [..**..], then the Initial Royalty owed by GSK
for such Calendar Year would be a total of [..**..] U.S. Dollars [..**..],
determined as follows:

<TABLE>
<CAPTION>
 AGGREGATE NET SALES         INCREMENTAL ROYALTY RATE
IN THE GSK TERRITORY          ON AGGREGATE NET SALES
 IN A CALENDAR YEAR           AND THE ROYALTY AMOUNT
--------------------   ------------------------------------
<S>                    <C>
[..**..] to [..**..]   [..**..], which would equal [..**..]

[..**..] to [..**..]   [..**..], which would equal [..**..]

[..**..] to [..**..]   [..**..], which would equal [..**..]
</TABLE>

          (b) Reduced Royalty.

               (i) Amount. In further consideration for the licenses granted to
GSK by Myogen in this Agreement, including licenses to the Myogen Know-How and
Myogen Trademark, and subject to Sections 9.2(b)(ii), 9.2(d), 9.3 and 9.4, GSK
will pay to Myogen a percentage of Net Sales in each Calendar Year (the "Reduced
Royalty") as follows:

<TABLE>
<CAPTION>
                       INCREMENTAL REDUCED ROYALTY RATE
 AGGREGATE NET SALES     ON AGGREGATE NET SALES IN THE
IN THE GSK TERRITORY   GSK TERRITORY IN A CALENDAR YEAR
--------------------   --------------------------------
<S>                    <C>
[..**..] to [..**..]               [..**..]

[..**..] to [..**..]               [..**..]
</TABLE>

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


                                       43

<PAGE>

<TABLE>
<S>                    <C>
[..**..]                           [..**..]
</TABLE>

GSK acknowledges and agrees that if there has not been a reduction in Myogen's
royalty obligation under the Abbott Agreement pursuant to Section 5.4(b) of the
Abbott Agreement, then notwithstanding the foregoing, GSK will in no event pay
to Myogen less than the royalties owed by Myogen under the Abbott Agreement on
Net Sales.

               (ii) Commencement and Expiration. GSK's obligation to pay the
Reduced Royalty on aggregate Net Sales in a Calendar Year as provided in Section
9.2(b)(i) will commence on a country-by-country basis upon expiration of GSK's
obligation to pay the Initial Royalty as provided in Section 9.2(a)(ii) and will
continue for the duration of the period during which royalties are owed by
Myogen to Abbott under the Abbott Agreement.

               (iii) Royalty to Abbott. For the avoidance of doubt, the Parties
acknowledge and agree that the Reduced Royalty payable by GSK to Myogen on Net
Sales as provided in this Section 9.2(b) are inclusive of any royalties or
consideration of any kind owed by Myogen to Abbott under the Abbott Agreement
based on sales of Product in the GSK Territory, and that GSK will not owe any
additional consideration to Myogen and/or Abbott on Net Sales in any country in
the GSK Territory in any period during the Term in which GSK is paying the
Reduced Royalty.

          (c) Third Party Royalties. The Parties acknowledge that, during the
Term, one (1) or more royalty-bearing licenses may be required from one (1) or
more Third Parties in order for GSK and its Affiliates to make, have made, use,
sell, offer for sale and import Compound and Product in the Field in the
Territory without infringing the intellectual property rights of one or more
patent rights of such Third Parties in the Territory. In such an event, GSK will
have the right but not the obligation, and only after prior consultation with
Myogen, to use Commercially Reasonable Efforts to obtain and maintain such Third
Party licenses. If, as a result of GSK obtaining and maintaining such Third
Party licenses, it is necessary for GSK to make royalty payments and/or license
fee payments to such Third Party (collectively, the "Third Party Payments") in
order for GSK to practice the rights granted in Section 2.1 without infringing
such Third Party's rights, GSK will be entitled to offset [..**..] of all such
Third Party Payments against any Royalties owed to Myogen pursuant to Section
9.2(a) during the Term; provided, however, that in no event shall such deduction
operate to reduce the Royalties due to Myogen under Section 9.2(a) in any
Calendar Quarter to less than [..**..] of the Royalties that would otherwise be
payable hereunder in respect of such Net Sales, but for this Section 9.2(c) or
[..**..] that owed by Myogen on Net Sales under the Abbott Agreement.

          (d) Compulsory Licenses and Compulsory Competition. If any Regulatory
Authority in any country within the GSK Territory grants or compels Myogen to
grant a compulsory license under the Myogen Intellectual Property and/or Abbott
Intellectual Property to a Third Party to sell Product in such country in the
GSK Territory at a royalty rate that is lower than the Initial Royalty or the
Reduced Royalty, as applicable, in the relevant country, then the Initial
Royalty or Reduced Royalty, as applicable, in the relevant country, will be
adjusted to [..**..] royalty rate granted to such Third Party, for so long as
such Third Party is selling such Product in the Field in such country in the GSK
Territory under the compulsory license.

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


                                       44

<PAGE>

     Section 9.3 Payment Terms.

          (a) Quarterly Payments of Royalties. Within [..**..] after the last
day of each Calendar Quarter, GSK will pay to Myogen all Royalties due and
payable on Net Sales in the immediately preceding Calendar Quarter, or portion
thereof if applicable, in accordance with Section 9.2(a) or (b).

          (b) Annual Reconciliation of Royalties. Within [..**..] after the last
day of each Calendar Year during the Term, or portion thereof if applicable, GSK
will calculate the Royalties due to Myogen pursuant to Section 9.2(a) or (b) for
such Calendar Year. In the event the total Royalties due pursuant to Section
9.2(a) or (b) in any Calendar Year is greater than the total Royalties that GSK
has paid under Section 9.2(a) or (b) in such Calendar Year, the difference will
be paid by GSK to Myogen within [..**..] after the last day of such Calendar
Year, or portion thereof if applicable. In the event the total Royalties due
pursuant to Section 9.2(a) or (b) in any Calendar Year is less than the total
Royalties that GSK has paid in such Calendar Year under Section 9.2(a) or (b),
the difference will be paid by Myogen to GSK within [..**..] after the last day
of such Calendar Year, or portion thereof if applicable.

          (c) Manner of Payment. All payments made under this Agreement will be
made in U.S. dollars. All payments will be made by wire transfer in immediately
available funds to one or more bank accounts to be designated in writing by
Myogen. Net Sales will be calculated in accordance with the International
Financial Reporting Standards consistently applied. Net Sales in currencies
other than U.S. dollars will be converted into U.S. dollars using the applicable
average exchange rates as calculated and utilized by GSK's group reporting
system and published accounts. The current method uses spot exchange rates
sourced from Reuters/Bloomberg, consistently applied, and if changed, GSK will
notify Myogen of the revised method in advance of it being applied; provided,
however, that any revisions to such method which materially and adversely
affects the calculation of the payments due to Myogen under this Agreement must
be consented to by Myogen in advance of the revised method being applied, which
consent will not be unreasonably withheld or delayed. In the event that any
uncontested payment due under this Agreement is not made when due, the payment
will accrue interest from the date due at an interest rate per annum equal to
[..**..]. The payment of such interest will not limit a Party from exercising
any other rights it may have as a consequence of the lateness of any payment.

          (d) Records and Reports. Any and all Royalty payments made by GSK to
Myogen pursuant to this Agreement will be accompanied by a written statement
setting forth the calculation of Net Sales and Royalties due on a
country-by-country basis, and, if applicable, the calculation of the average
exchange rate utilized by GSK to convert a local currency payment to U.S.
dollars and the calculation of Royalties due on such sales. In addition, within
[..**..] after the end of each [..**..], GSK shall provide to Myogen via email
or facsimile a detailed, unaudited report of Net Sales recorded in such
[..**..]. GSK will maintain, and will require its Affiliates, and Sublicensees
(but excluding those Distributors who have distribution agreements with GSK as
of the Effective Date), to maintain complete and accurate records sufficient to
enable accurate calculation of Royalties due by GSK to Myogen hereunder, for a
period of a

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


                                       45

<PAGE>

least [..**..] after the date of the royalty payment to which they pertain.

          (e) Audit Rights. GSK will permit an independent public accountant
designated by Myogen and reasonably acceptable to GSK (the "Auditor"), to have
access, no more than once in each Calendar Year, during regular business hours
and upon at least thirty (30) calendar days' prior written notice, to GSK's
records and books, and GSK's Affiliates' and Sublicensees' records and books, to
the extent necessary to determine the accuracy of GSK's Net Sales reported, and
Royalty payments made, by GSK to Myogen pursuant to this Section 9.3 within the
[..**..] period immediately preceding such an audit. If such examination by the
Auditor results in a determination that GSK's Net Sales or Royalty payments owed
to Myogen by GSK have been understated, unpaid amounts due will be paid by GSK
to Myogen promptly. If such examination results in a determination that GSK's
Net Sales or Royalty payments owed to Myogen by GSK have been overstated,
overpaid amounts due will be re-paid by Myogen to GSK promptly. The fees and
expenses of such Auditor will be paid by Myogen unless GSK's Net Sales have been
understated, or that payments owed to Myogen by GSK have been underpaid, by more
than [..**..] for the period examined, in which case GSK will pay all reasonable
costs and expenses of the Auditor incurred by Myogen in the course of making
such determination. The Auditor will report to Myogen only its conclusions as to
whether GSK is in compliance with its Royalty obligations and the amount of any
underpayment or overpayment, and such report and the conclusions contained
therein will constitute GSK Confidential Information. In addition to the
foregoing, if Myogen's auditors, as part of an audit of Myogen, require an
understanding and review of GSK's accounting controls and processes, GSK will
use Commercially Reasonable Efforts to assist such auditors with such required
review.

     Section 9.4 Taxes. To the extent a statutory tax withholding obligation is
imposed by a governmental authority upon any payment made by GSK to Myogen under
this Agreement, including, without limitation Milestone Payments and Royalties,
GSK will be entitled to withhold from such payment the amount, if any, of any
tax assessed against Myogen, provided that such tax is only for the account of
Myogen. GSK will pay the amount of such tax to the proper taxing authority and
will provide evidence of the payment of such tax to Myogen within thirty (30)
days of payment, provided that such evidence is routinely provided to GSK by the
relevant taxing authority and that Myogen completes the Inland Revenue Form
US/Company 2002 prior to receipt of any payment from GSK as provided under this
Agreement. At Myogen's reasonable request and subject to Myogen reimbursing any
costs and expenses of GSK related thereto, GSK will reasonably assist Myogen in
any effort to claim any exemption from such deductions or withholdings under any
double taxation or similar agreement or treaty from time to time in force, and
in minimizing the amount required to be so withheld or deducted.

                                    ARTICLE X

                        PATENT PROSECUTION AND LITIGATION

     Section 10.1 Responsibility for Myogen Patent Rights.

          (a) Myogen will continue to have responsibility for and control over,
and will

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


                                       46

<PAGE>

use its commercially reasonable efforts with regard to the Patent Prosecution of
the Myogen Patent Rights. Myogen will bear all the costs and expenses associated
with its Patent Prosecution of the Myogen Patent Rights in the Territory. Myogen
will provide GSK with a report every Calendar Quarter during the Term
summarizing the patent filings, prosecutions or other proceedings in the GSK
Territory, and will provide GSK with copies of substantive and material
communications, search reports and Third Party observations submitted to or
received from patent offices throughout the GSK Territory. Notwithstanding the
foregoing, GSK will have the right to review all pending patent applications
included within the Myogen Patent Rights in the GSK Territory, significant
filings and other significant proceedings which relate, directly or indirectly,
to GSK's Development, Manufacture and/or Commercialization of Product in the
Field in the GSK Territory, and make recommendations to Myogen concerning them
and their conduct, which recommendations Myogen will consider in good faith. GSK
will provide any such patent consultation to Myogen at no cost to Myogen.

          (b) Should Myogen elect to abandon any Patent Right in the GSK
Territory contained in the Myogen Patent Rights (the "Abandoned Myogen Patent
Rights"), it will (i) provide GSK with written notice as soon as reasonably
possible after making such election but in any event no later than sixty (60)
calendar days after making such election but in any event before a possible loss
of rights, and GSK will have the right to conduct Patent Prosecution of the
Abandoned Myogen Patent Rights in its sole discretion, at its sole expense and
in GSK's name, Myogen's name or the name of both GSK and Myogen, as determined
by GSK in its sole discretion.

     Section 10.2 Ownership of Inventions. Myogen will have and retain sole and
exclusive title to all inventions, discoveries and know-how which are invented
solely by its employees, agents or other Persons acting under its authority in
the course of or as a result of this Agreement ("Myogen Inventions"). GSK will
have and retain sole and exclusive title to any and all inventions, discoveries
and know-how which are invented solely by its employees, agents or other Persons
acting under its authority in the course of or as a result of this Agreement
("GSK Inventions"). The Parties shall jointly own all such inventions,
discoveries and know-how which are invented jointly by employees, agents, or
other Persons acting under the authority of both Parties in the course of or as
a result of this Agreement ("Joint Inventions"). Inventorship will be determined
in accordance with United States patent law at the time the inventor made the
invention. Except as otherwise expressly provided in this Agreement, including
with respect to the rights and licenses granted or retained hereunder, and the
royalty obligations set forth in this Agreement, each joint owner may make, use,
sell, keep, license, assign, or mortgage such Joint Invention, and otherwise
undertake all activities a sole owner might undertake with respect to such Joint
Inventions without the consent of and without accounting to the other joint
owner. GSK shall not assert against Myogen or its Affiliates any Patent Rights
relating to any GSK Inventions.

     Section 10.3 Patent Filings.

          (a) Myogen will have the first right, but not the obligation, to
conduct Patent Prosecution of Patent Rights on Myogen Inventions, at its own
expense. Should Myogen elect not to conduct Patent Prosecution with respect to
any Patent Rights on a Myogen Invention (but

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EXCHANGE COMMISSION PURSUANT TO RULE 24B-2 OF THE SECURITIES EXCHANGE ACT OF
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only to the extent such Patent Rights relate to Compound and/or Product), it
will (i) provide GSK with written notice as soon as reasonably possible after
making such election but in any event no later than sixty (60) calendar days
before a possible loss of such Patent Rights, (ii) give GSK the right, at GSK's
discretion and sole expense, to conduct Patent Prosecution of such Patent Rights
in Myogen's name, and (iii) offer reasonable assistance in connection with such
preparation and filing at no cost to GSK except for reimbursement of reasonable
out-of-pocket expenses incurred by Myogen in rendering such assistance.

          (b) GSK will have the first right, but not the obligation, to conduct
Patent Prosecution of Patent Rights on GSK Inventions, at its sole expense.
Should GSK elect not to conduct Patent Prosecution with respect to any Patent
Rights on a GSK Invention (but only to the extent such Patent Rights relate to
Compound and/or Product) it will (i) provide Myogen with written notice as soon
as reasonably possible after making such election but in any event no later than
sixty (60) calendar days before a possible loss of such Patent Rights, (ii) give
Myogen the right, at Myogen's discretion and sole expense, to conduct Patent
Prosecution of such Patent Rights in GSK's name, and (iii) offer reasonable
assistance in connection with such preparation and filing at no cost to Myogen
except for reimbursement of reasonable out-of-pocket expenses incurred by GSK in
rendering such assistance.

          (c) GSK will have the first right, but not the obligation, to conduct
Patent Prosecution of Patent Rights in the GSK Territory on Joint Inventions, in
the names of both GSK and Myogen. Should GSK elect not to conduct Patent
Prosecution with respect to any Patent Rights in the GSK Territory on a Joint
Invention it will (i) provide Myogen with written notice as soon as reasonably
possible after making such election but in any event no later than sixty (60)
calendar days before a possible loss of rights, (ii) give Myogen the right, at
Myogen's discretion and sole expense, to continue to conduct Patent Prosecution
of such Patent Rights in the GSK Territory in both Myogen's and GSK's name, and
(iii) offer reasonable assistance in connection with such preparation and filing
at no cost to Myogen except for reimbursement of reasonable out-of-pocket
expenses incurred by GSK in rendering such assistance. Myogen, at its discretion
and cost, will prosecute such application(s) and maintain any Patent Rights
derived therefrom in both GSK's and Myogen's name. Myogen will have the first
right, but not the obligation, to conduct Patent Prosecution of Patent Rights in
the Myogen Territory on Joint Inventions, in the names of both GSK and Myogen.
Should Myogen elect not to conduct Patent Prosecution with respect to any Patent
Rights in the Myogen Territory on a Joint Invention it will (i) provide GSK with
written notice as soon as reasonably possible after making such election but in
any event no later than sixty (60) calendar days before a possible loss of
rights, (ii) give GSK the right, at GSK's discretion and sole expense, to
continue to conduct Patent Prosecution of such Patent Rights in the Myogen
Territory in both Myogen's and GSK's name, and (iii) offer reasonable assistance
in connection with such preparation and filing at no cost to GSK except for
reimbursement of reasonable out-of-pocket expenses incurred by Myogen in
rendering such assistance. GSK, at its discretion and cost, will prosecute such
application(s) and maintain any Patent Rights derived therefrom in both GSK's
and Myogen's name.

          (d) The Parties agree to cooperate in the Patent Prosecution of all
Patent Rights filed under this Section 10.3, including obtaining and executing
necessary powers of attorney and assignments by the named inventors, providing
relevant technical reports to the

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Party conducting the Patent Prosecution concerning the invention disclosed in
such patent application, obtaining execution of such other documents which will
be needed in the filing and prosecution of such patent applications, seeking
patent protection in the major commercial markets of the other Party's portion
of the Territory similar to the patent protection it seeks in its own portion of
the Territory, and, as requested, updating each other regarding the status of
such patent applications.

     Section 10.4 Infringement of a Myogen Patent Right.

          (a) In the event that either Party becomes aware of actual or
threatened infringement of a Patent Right included within the Myogen Patent
Rights anywhere in the GSK Territory by a Third Party, that Party will promptly
notify the other Party in writing. GSK will have the first right, but not the
obligation, to bring, at its own expense, an infringement action against any
Third Party. If GSK does not commence a particular infringement action within
ninety (90) calendar days of receipt of the notice of infringement, then Myogen,
after notifying GSK in writing, will be entitled but will have no obligation to
bring such infringement action at its own expense. The Party conducting such
action will have full control over its conduct, including settlement thereof
subject to Section 10.5. In any event, GSK and Myogen will provide reasonable
assistance to one another and will reasonably cooperate in any such litigation
at the other's request [..**..] to the requesting Party.

          (b) In the event that either Party becomes aware of actual or
threatened infringement of a Patent Right included within the Myogen Patent
Rights anywhere in the Myogen Territory by a Third Party, that Party will
promptly notify the other Party in writing. Myogen will have the right, but not
the obligation, to bring, at its own expense, an infringement action against any
such Third Party. Myogen will have full control over its conduct, including
settlement thereof subject to Section 10.4(d).

          (c) Myogen and GSK will recover their respective actual and reasonable
out-of-pocket expenses associated with any litigation or settlement thereof from
any recovery made by any Party. In the event GSK was the Party to commence an
infringement action pursuant to Section 10.4(a), then any excess amount
attributable to compensatory and punitive damages for infringement of any Patent
Right included within Myogen Patent Rights will be shared between Myogen and
GSK, provided that Myogen's share of any excess amount attributable to
compensatory and punitive damages for sales of the product that was the subject
of the litigation will be limited to the amount of Royalties that Myogen would
have been entitled to receive had those been sales of Product in the Field in
the GSK Territory made by GSK, or its Affiliates or Sublicensees as provided in
this Agreement. In the event Myogen was the Party to commence an infringement
action pursuant to Section 10.4(b), then any excess amount attributable to
infringement of any Patent Rights included within the Myogen Patents will be
retained solely by Myogen.

          (d) The Parties will keep one another informed of the status of and of
their respective activities regarding any litigation or settlement thereof
concerning the Myogen Patent Rights, provided however that no settlement or
consent judgment or other voluntary final disposition of any suit or action
pursuant to this Section 10.4 may be entered into without the

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BY BRACKETS, HAS BEEN OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
EXCHANGE COMMISSION PURSUANT TO RULE 24B-2 OF THE SECURITIES EXCHANGE ACT OF
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consent of the other Party if such settlement would subject the other Party to
an injunction or if such settlement or judgment would materially diminish or
limit or otherwise materially and adversely affect the rights, activities or
financial interests of the other Party.

          (e) Each Party shall retain the right to be represented by counsel
[..**..] in any suit or other action instituted by the other pursuant to this
Section 10.4.

     Section 10.5 Infringement of an Abbott Patent Right.

          (a) In the event that either Party becomes aware of actual or
threatened infringement of a Patent Right included within the Abbott Patent
Rights anywhere in the GSK Territory by a Third Party, that Party will promptly
notify the other Party in writing.

          (b) In accordance with section 9.2 of the Abbott Agreement, Abbott
will have the first right, but not the obligation, to bring, at its own expense,
an infringement action against any Third Party in the GSK Territory. Allocation
of any proceeds received pursuant to such action shall be determined in
accordance with section 9.2 of the Abbott Agreement. If GSK was represented by
counsel in such action, then any amounts received by Myogen in excess of
reimbursement for Myogen's costs shall be divided equally between Myogen and
GSK. If Abbott elects pursuant to section 9.2(a)(iii) of the Abbott Agreement to
delegate such right to bring an infringement action to Myogen, then Myogen shall
have the right to institute and prosecute an action or proceeding to abate such
infringement and to resolve such matter by settlement or otherwise. If Abbott
elects to so delegate, then Myogen, at GSK's request and subject to Abbott's
consent, shall delegate to GSK the first right to bring, at its own expense, an
infringement action against any Third Party in the GSK Territory. The Party
conducting such action will have full control over its conduct, including
settlement thereof subject to Section 10.5(e). In any event, GSK and Myogen will
provide reasonable assistance to one another and will reasonably cooperate in
any such litigation at the other's request [..**..] to the requesting Party.

          (c) In the event that either Party becomes aware of actual or
threatened infringement of a Patent Right included within the Abbott Patent
Rights anywhere in the Myogen Territory by a Third Party, that Party will
promptly notify the other Party in writing. As between Myogen and GSK, Myogen
will have the right, but not the obligation, to bring, at its own expense, an
infringement action against any such Third Party. As between Myogen and GSK,
Myogen will have full control over its conduct, including settlement thereof
subject to Section 10.5 (e).

          (d) With respect to any infringement action commenced in the GSK
Territory by Myogen or GSK pursuant to this Article X, each Party, and Abbott if
Abbott joined such action as a party plaintiff, will recover their respective
actual and reasonable out-of-pocket expenses associated with any litigation or
settlement thereof from any recovery made by any Party. In the event GSK was the
Party to commence an infringement action pursuant to Section 10.5(b), then any
excess amount attributable to compensatory and punitive damages for infringement
of any Patent Right included within Abbott Patent Rights will be shared between
Myogen and GSK. In the event Myogen was the Party to commence an infringement
action

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pursuant to Section 10.5(b), then, as between Myogen and GSK, any excess amount
attributable to infringement of any Patent Rights included within the Abbott
Patents will be retained solely by Myogen.

          (e) With respect to any infringement suit or action commenced by
Myogen or GSK pursuant to this Article X, the Parties will keep one another
informed of the status of and of their respective activities regarding any
litigation or settlement thereof concerning the Abbott Patent Rights, provided
however that no settlement or consent judgment or other voluntary final
disposition of any such suit or action may be entered into without the consent
of the other Party if such settlement would subject the other Party to an
injunction or if such settlement or judgment would materially diminish or limit
or otherwise materially and adversely affect the rights, activities or financial
interests of the other Party.

     Section 10.6 Responsibility for Abbott Patent Rights.

          (a) In accordance with section 11.2 of the Abbott Agreement, Abbott
shall be solely responsible for preparation, filing, prosecution and maintenance
of the Abbott Patent Rights in the GSK Territory. Subject to Abbott's consent,
Myogen shall provide GSK with copies of substantive and material communications,
search reports and Third Party observations submitted to or received from patent
offices throughout the GSK Territory. Myogen shall provide to Abbott any GSK
recommendations made available to Myogen concerning such communications, reports
and observations. GSK will provide any such patent consultation to Myogen at no
cost to Myogen.

          (b) In accordance with section 11.2 of the Abbott Agreement, should
Myogen assume any duties set forth in Section 10.6 (a), then: (i) Myogen, in
consultation with GSK, shall have responsibility for and control over, and will
use its commercially reasonable efforts with regard to the Patent Prosecution of
such Abbott Patent Rights; (ii) subject to Abbott's consent, Myogen will provide
GSK with copies of substantive and material communications, search reports and
Third Party observations submitted to or received from patent offices throughout
the GSK Territory; and (iii) GSK will have the right to review all pending
patent applications included within the Abbott Patent Rights in the GSK
Territory, significant filings and other significant proceedings which relate,
directly or indirectly, to GSK's Development, Manufacture and/or
Commercialization of Product in the Field in the GSK Territory, and make
recommendations to Myogen concerning them and their conduct, which
recommendations Myogen will reasonably accept, provided that such
recommendations, in Myogen's good faith determination, do not adversely affect
the Abbott Patent Rights inside or outside the Territory. Myogen will bear all
the costs and expenses associated with its Patent Prosecution of the Abbott
Patent Rights in the GSK Territory pursuant to this Section 10.6(b). GSK will
provide any such patent consultation to Myogen at no cost to Myogen.

          (c) Should Myogen elect to abandon any Patent Right contained in the
Abbott Patent Rights for which it has assumed responsibility for under Section
10.6(b) (the "Abandoned Abbott Patent Rights"), it will (i) provide GSK with
written notice as soon as reasonably possible after making such election but in
any event no later than sixty (60) calendar days after making such election but
in any event before a possible loss of rights, and, subject to Abbott's consent,

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GSK will have the right to conduct Patent Prosecution of the Abandoned Abbott
Patent Rights in its sole discretion, at its sole expense and in GSK's name,
Myogen's name or the name of both GSK and Myogen, as determined by GSK in its
sole discretion.

     Section 10.7 Third Party Action Against GSK. In the event of the
institution of any suit by a Third Party against GSK or GSK's Affiliates,
sublicensees for patent infringement involving the Product, GSK will promptly
notify Myogen in writing. Except as otherwise provided for under this Agreement,
GSK will have the first right, but not the obligation, to defend such suit at
its own expense; provided that Myogen will have the right, at its sole
discretion, to participate in any such suit and to be represented by counsel of
its own choice at its own expense. Myogen will provide reasonable assistance to
GSK and reasonably cooperate in any such litigation at GSK's request without
expense to Myogen. Any and all settlements that restrict the scope or
enforceability of the Myogen Intellectual Property or the Development or
Commercialization of the Product in the Field in the Myogen Territory or the
Product in any other field in the Territory must be approved by Myogen, in its
sole and absolute discretion, before execution by GSK. Myogen shall not be
required to approve any settlement that does not include as a condition thereof
the granting to Myogen of a full and unconditional release of claims.

                                   ARTICLE XI

                              TERM AND TERMINATION

     Section 11.1 Term. The term of this Agreement (the "Term") will commence on
the Effective Date and, unless sooner terminated as provided in Sections 11.2,
11.3, 11.4, 11.5, 11.6, 11.7 and 11.8, will expire on a country-by-country basis
on the date of the expiration of GSK's obligation to pay Royalties in such
country, as provided in Section 9.2. Upon the expiration of GSK's obligation to
pay Royalties in a given country in the GSK Territory (as such term is defined
from time-to-time) under Section 9.2, GSK will be permitted to make, have made,
use, sell, offer for sale and import Product in the Field in such country, and
use the Abbott Know-How and Myogen Know-How in such country without further
payments or other remuneration to Myogen.

     Section 11.2 Termination for Material Breach. Subject to the limitation set
forth in Section 5.2(a)(ii), each Party will be entitled to terminate this
Agreement in its entirety by written notice to the other Party in the event that
the other Party is in material default or breach of any of its obligations
hereunder, and fails to remedy any such default or breach within [..**..] or, in
the case of failure to pay amounts due hereunder, [..**..] (respectively, the
"Cure Period") after notice thereof by the non-defaulting/non-breaching Party.
If such default or breach is not corrected within the applicable Cure Period,
the non-defaulting/non-breaching Party will have the right to immediately
terminate this Agreement by giving written notice to the Party in default or
breach. Notwithstanding the foregoing, Myogen acknowledges and agrees that it
will not have any right to terminate this Agreement in its entirety pursuant to
this Section 11.2 in the event of any breach by GSK of Sections 5.2(a)(ii), 6.1
or 6.3.

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     Section 11.3 Termination for Safety Issues. GSK may, upon [..**..] written
notice to Myogen, terminate this Agreement in its entirety if (i) the withdrawal
of the Product in the Field from the market in one (1) or more countries in the
GSK Territory for health or safety reasons is commenced by GSK or ordered or
required by the EMEA or other Regulatory Authority, or (ii) substantially all
ongoing Development of the Product is discontinued in the GSK Territory or
ordered or required to be terminated by the EMEA or other Regulatory Authority
for health or safety reasons.

     Section 11.4 By Mutual Consent. The Parties may terminate this Agreement
with respect to any country in the GSK Territory or in its entirety at any time
and for any reason during the Term upon their mutual written agreement.

     Section 11.5 Bankruptcy. Either Party may terminate this Agreement in its
entirety at any time during the Term by giving written notice to the other Party
if the other Party files in any court or agency pursuant to any statute or
regulation of any state or country, a petition in bankruptcy or insolvency or
for reorganization or for an arrangement or for the appointment of a receiver or
trustee of the Party or of its assets, or if the other Party is served with an
involuntary petition against it, filed in any insolvency proceeding, and such
petition will not be dismissed with sixty (60) calendar days after the filing
thereof, or if the other Party makes a general assignment for the benefit of
creditors.

     Section 11.6 Termination by GSK in Connection with Challenge of Orphan Drug
Medicinal Product Designation. GSK may immediately terminate this Agreement in
its entirety if the EMEA's decision to grant orphan medicinal product
designation for Product in the Field is challenged by any Third Party, provided
that the right provided by this Section 11.6 shall terminate and no longer be
available to GSK [..**..] after GSK's, its Affiliates' or any of their
Sublicensees' First Commercial Sale of a Product in a Major European Market
Country.

     Section 11.7 Termination by GSK. GSK may immediately terminate this
Agreement with respect to any country in the GSK Territory or in its entirety at
any time during the Term, for any reason whatsoever, by giving Myogen at least
six (6) months' prior written notice thereof.

     Section 11.8 Termination by Myogen.

          (a) If GSK does not launch the Product in at least [..**..] of the
Major European Market Countries within [..**..] of receiving Regulatory Approval
and pricing and reimbursement approval (where required) that are reasonably
commercially acceptable to GSK in [..**..] of the Major European Market
Countries, then Myogen may terminate this Agreement in its entirety (except as
to Japan) or as to every country in the European Economic Area upon providing
GSK with at least [..**..] prior written notice thereof; provided, however, that
Myogen will not have the termination rights set forth in this Section 11.8 if
GSK's failure to launch the Product as provided herein is caused in whole or in
part by any of the following:

               (i) a request from, or other action of, any Regulatory Authority
of competent jurisdiction which prevents the Commercialization of Product in at
least [..**..]

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Major European Market Countries;

               (ii) the grant of a temporary or permanent injunction or other
similar action against GSK and/or any of its Affiliates or sublicensees by a
court of competent jurisdiction prohibiting or restraining GSK and/or any of its
Affiliates or sublicensees from Commercializing Product in at least [..**..]
Major European Market Countries; or

               (iii) the inability of GSK or its Affiliates or sublicensees to
Manufacture and/or have Manufactured sufficient commercial quantities of Product
reasonably required by GSK or its Affiliates or sublicensees to Commercialize
Product in at least [..**..] Major European Market Countries, despite GSK or its
Affiliates or Third Parties using Commercially Reasonable Efforts (including,
without limitation, purchasing Product from Myogen or its suppliers on
commercially reasonable terms).

          (b) If GSK, in its sole discretion, elects to terminate the European
Critical Care Business Unit, then GSK will promptly provide Myogen with written
notice of such termination and provide Myogen with GSK's plan for
Commercializing the Product in the European Economic Area subsequent to such
termination. If, in any [..**..] Calendar Quarters of the [..**..] period
following the effective date of termination of the European Critical Care
Business Unit or if during the [..**..] period following the [..**..]
anniversaries of the effective date of GSK's termination of the European
Critical Care Business Unit, the Royalties received by Myogen with respect to
the European Economic Area decrease by more than [..**..] than the Royalties
received with respect to the European Economic Area during the consecutive
Calendar Quarters or [..**..] period, as the case may be, immediately preceding
the effective date of GSK's termination of the European Critical Care Business
Unit (for reasons unrelated to the expiration of the Initial Royalty as provided
in Section 9.2(a)(ii), a reduction in the Royalty as provided in Section 9.2(c),
and/or a reduction in the Royalty as provided in Section 9.2(d), then Myogen may
terminate this Agreement in its entirety (excluding Japan) upon providing GSK
with at least [..**..] prior written notice thereof. In addition, if GSK
terminates the European Critical Care Business Unit prior to the commencement of
Product sales in the Major European Market Countries and does not replace the
European Critical Care Business Unit with similar capabilities to conduct
Commercialization activities commensurate with an overall strategy for the
European Economic Area, then Myogen may terminate this Agreement in its entirety
(excluding Japan) upon providing GSK with at least [..**..] prior written notice
thereof.

     Section 11.9 Effect of Termination.

          (a) Termination By Myogen or by GSK for Convenience or Safety Issues.
If Myogen terminates this Agreement with respect to a particular Major Country
or Major European Market Country pursuant to Section 6.2, with respect to any
country pursuant to Section 5.2(a)(ii), with respect to any country pursuant to
Section 6.5, with respect to the European Economic Area pursuant to Section
11.8, or in its entirety pursuant to either Section 11.2 or 11.8, or GSK
terminates this Agreement pursuant to any of Sections 11.3, 11.6 or 11.7, then
all licenses and sublicenses granted to GSK by Myogen under this Agreement (or,
as applicable, in the particular country) will terminate, and all rights therein
will revert to Myogen. Upon such termination, the following provisions apply:

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               (i) GSK will, to the extent permitted under Applicable Law and
subject to the last sentence of this Section 11.9(a)(i), promptly assign and
surrender to Myogen in the GSK Territory (in the case of termination of this
Agreement in its entirety) or in such country(ies) (in the case of termination
in respect of a particular country or countries) all Regulatory Approvals, if
any, for Product and all pending Regulatory Approval Applications (including the
MAAs in the case of termination pursuant to Section 11.2 or 11.8) for the
Product and, in each case, copies of all documents related thereto, at a cost to
Myogen to be mutually agreed upon by the Parties based on GSK's reasonable costs
of preparation and filing of such documents. GSK will take all actions
reasonably necessary to timely effect the transfer of each such item to Myogen,
including, without limitation, by making such filings as may be required with
Regulatory Authorities and other governmental authorities in the affected
countries of the GSK Territory that may be necessary to record such assignment
or effect such transfer or, at Myogen's request, complete any regulatory filings
pending in the affected countries of the GSK Territory in respect of the
Product. Notwithstanding anything to the contrary contained in this Section
11.9(a)(i), in the event that this Agreement is terminated by Myogen as provided
in Sections 6.2 or 6.5 with respect to any country in the European Economic
Area, GSK will continue to own all Regulatory Approvals and pending Regulatory
Approval Applications applicable to Product in the Field in such country
(including, without limitation, the MAA) and GSK will have no obligation to
assign and/or surrender such Regulatory Approvals and pending Regulatory
Approval Applications to Myogen; however, GSK will promptly designate Myogen or
Myogen's designee as GSK's local representative in such country with respect to
the Development and Commercialization of Product in the Field and GSK will take
all actions reasonably necessary to effectuate such designation, including,
without limitation, by making such filings as may be required with Regulatory
Authorities and other governmental authorities in such country that may be
necessary to record such designation.

               (ii) GSK will provide to Myogen (A) copies of all promotional
materials (including any copyright rights therein; provided, however no rights
to use any GSK Marks or any tradenames or housemarks of GSK or its Affiliates is
created or implied by this grant), and (B) GSK's then-current supply of Product,
if any, in each case in the GSK Territory (in the case of termination of this
Agreement in its entirety) or in such country(ies) (in the case of termination
in respect of a particular country or countries), in each case at a cost to
Myogen to be mutually agreed upon by the Parties.

               (iii) GSK will assign to Myogen, to the extent assignable and at
Myogen's request, GSK's rights in any or all Third Party agreements for
licenses, services or supplies necessary for the further Development,
Manufacture and Commercialization of the Product in the GSK Territory (in the
case of termination of this Agreement in its entirety) or in such country(ies)
(in the case of termination in respect of a particular country or countries).

               (iv) Effective upon the effective date of such termination, for
each country so terminated, or for the GSK Territory in the case of termination
of this Agreement in its entirety, GSK hereby grants to Myogen a non-exclusive,
royalty-free license, with the right to grant and authorize the grant of
sublicenses in the same manner as set forth in Section 2.4(b), under the GSK
Intellectual Property, to make, have made, use, sell, offer for sale and import
the

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Product in each such country so terminated or for the GSK Territory in the case
of termination of this Agreement in its entirety.

               (v) If the First Commercial Sale of the Product has occurred in
the GSK Territory as of the effective date of termination, then for each country
so terminated, or for the GSK Territory in the case of termination of this
Agreement in its entirety, GSK hereby grants to Myogen a license under the GSK
Marks for use solely in connection with the Product in each such country so
terminated or for the GSK Territory in the case of termination of this Agreement
in its entirety.

               (vi) In addition, if the First Commercial Sale has occurred in
the GSK Territory at the time of such termination and the Agreement is not being
terminated by GSK under Section 11.3 or Myogen under 11.2, but is being
terminated in its entirety, then at GSK's election, (A) GSK will transfer to
Myogen GSK's existing inventory of the Product as is in good and saleable
condition, in its original, unopened packaging, at the transfer price paid by
GSK for the Product, or (B) GSK will have the right to sell-through its existing
inventory of the Product for a period not to exceed [..**..] from the effective
date of termination, and such sales will be subject to the Royalty provisions
contained herein. At the end of any such sell-through period, all unsold
inventory will be returned to Myogen, and Myogen will repurchase such inventory
from GSK as is in good and saleable condition, in its original, unopened
packaging, at the transfer price paid by GSK for the Product.

          (b) Termination by GSK for Myogen Breach. If Myogen is in material
breach of its obligations hereunder, then following the expiration of any
applicable Cure Period, GSK may elect to either:

               (i) Terminate this Agreement in its entirety; or

               (ii) Elect to continue to exercise its rights under this
Agreement, in which case:

                    (A) The rights and obligations of the Parties under this
Agreement will remain in full force and effect; provided that GSK will assume
the obligations of Myogen under the Development Plan in respect of the Product
and will perform any and all obligations thereunder in accordance with the terms
of this Agreement; and

                    (B) GSK will, as its sole and exclusive remedy hereunder, be
entitled to off-set any documented, external costs it incurs as a result of the
assumption and completion of any Development activities that would have been
Myogen's responsibility under this Agreement and the Development Plan and that
GSK would not have otherwise paid or incurred against any milestone payments
owed to Myogen but not yet paid by GSK under Section 9.1(a) prior to such breach
by Myogen.

          (c) Termination by Mutual Agreement. If the Parties terminate this
Agreement pursuant to Section 11.4, GSK shall provide Myogen with all reasonable
assistance during a six (6) month period to effect the transfer of all
regulatory activities, Regulatory Approval Applications, MAAs and Regulatory
Approvals in the GSK Territory for the Product.

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


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The Parties shall agree upon, and the Joint Steering Committee shall coordinate,
the orderly transfer and wind-down of all Development, Manufacture and
Commercialization activities and useable Product and Compound to Myogen in the
GSK Territory. Effective upon the effective date of such termination, GSK hereby
grants to Myogen a non-exclusive, world-wide, royalty-free license, with the
right to grant and authorize the grant of sublicenses, under the GSK
Intellectual Property, to develop, make, have made, use, sell, offer for sale
and import the Product.

     Section 11.10 Survival Upon Termination or Expiration.

          (a) The following provisions will survive any expiration or
termination of this Agreement:

               (i) Sections 2.1, 2.2, 2.5, 2.6(c), 2.6(d), 5.2, 5.4, 6.5,
7.1(b), 8.1, 8.2, 10.3, 10.4, 10.5, 15.3, 15.4 and Articles IX and XII, all with
regard to GSK's post-termination/expiration sales of Product pursuant to Section
11.9(a)(vi);

               (ii) Sections 2.6(b), 2.7, 10.2, 10.3(c), 10.3(d) (only with
respect to Section 10.3(c)), 10.7, 11.9, 11.10, 15.1, 15.2, 15.3, 15.4(g), and
Articles XIII and XIV; and

               (iii) Article I for the sole purposes of interpreting the
obligations and liabilities between the Parties surviving termination of this
Agreement;

which will survive termination or expiration of this Agreement for the time
period specified in such Sections or Articles, as applicable, or if no such time
period is specified, indefinitely.

          (b) Upon termination of this Agreement, Myogen will have the right to
retain any sums already paid by GSK hereunder, and Myogen will have the right to
receive all payments previously accrued hereunder.

          (c) Termination of this Agreement will not relieve the Parties of any
liability which accrued hereunder prior to the effective date of such
termination, including any payment obligations, nor preclude either Party from
pursuing all rights and remedies it may have hereunder or at law or in equity
with respect to any breach of this Agreement nor prejudice either Party's right
to obtain performance of any obligation.

          (d) For the avoidance of doubt, upon the termination of this Agreement
in its entirety or with respect to a particular country, all of the sublicenses
and licenses under the Abbott Intellectual Property and Myogen Intellectual
Property granted by Myogen to GSK pursuant to Article II hereof (or, as
applicable, in the particular country), will terminate and GSK will no longer
have rights under the Abbott Intellectual Property or Myogen Intellectual
Property.

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


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                                   ARTICLE XII

                         REPRESENTATIONS AND WARRANTIES

     Section 12.1 Mutual Representations and Warranties. Myogen and GSK each
hereby represent and warrant to the other as follows, as of the Effective Date:

          (a) It is a corporation duly organized, validly existing and is in
good standing under the laws of its jurisdiction of formation, and has all
requisite power and authority, corporate or otherwise, to execute, deliver and
perform this Agreement.

          (b) The execution, delivery and performance of this Agreement have
been duly authorized by all necessary corporate action and do not and will not
(i) require any consent or approval of its stockholders, (ii) violate any
provision of any Applicable Law or any provision of its certificate of
incorporation, by-laws or other founding document, or (iii) result in a breach
of or constitute a default under any material agreement, mortgage, lease,
license, permit or other instrument or obligation to which it is a party or by
which it or its properties may be bound or affected.

          (c) It is not currently debarred, suspended or otherwise excluded by
any government agency from receiving government contracts that would adversely
affect its ability to perform its obligations hereunder.

          (d) It is not under any obligation to any Person, contractual or
otherwise, that is conflicting or inconsistent in any respect with the terms of
this Agreement or that would impede the diligent and complete fulfillment of its
obligations hereunder; except with respect to the Abbott Agreement, a copy of
which has been provided to GSK.

          (e) This Agreement is a legal, valid and binding obligation
enforceable against it in accordance with its terms and conditions, except as
such enforceability may be limited by applicable bankruptcy, insolvency,
moratorium, reorganization or similar laws, from time to time in effect,
affecting creditor's rights generally.

     Section 12.2 Myogen Representations and Warranties. Myogen represents and
warrants to GSK that as of the Effective Date:

          (a) it owns the entire right, title and interest in and to, or
otherwise has the right to grant the license or sublicense rights outlined in
Article II under the Abbott Intellectual Property and Myogen Intellectual
Property, all of which are, to Myogen's actual knowledge, free and clear of any
liens, mortgages, security interests, charges, encumbrances or otherwise;

          (b) it has not, up through and including the Effective Date, knowingly
withheld any material information in Myogen's possession from GSK in response to
GSK's reasonable inquiries in connection with GSK's due diligence relating to
Compound, Product, this Agreement and the underlying transaction, and to the
best of its knowledge, the information related to Product in the Field that
Myogen has provided to GSK prior to the Effective Date is up-to-date and
accurate in all material respects;

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


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          (c) it has not received notice from any Third Party of any issued and
enforceable patent of such Third Party in the Field and in the GSK Territory
which would be infringed by the making, having made, use, sale, offering for
sale or importing of Product in the Field in the GSK Territory as contemplated
by GSK pursuant to this Agreement;

          (d) to the best of its knowledge, the Myogen Patent Rights applicable
to the GSK Territory are not invalid nor unenforceable, nor that they are
subject to any pending or any threatened re-examination, opposition,
interference or litigation proceedings before any patent and trademark office,
court, or any other governmental entity in the GSK Territory;

          (e) to its actual knowledge, the Abbott Patent Rights applicable to
the GSK Territory are not invalid nor unenforceable, nor that they are subject
to any pending or any threatened re-examination, opposition, interference or
litigation proceedings before any patent and trademark office, court, or any
other governmental entity in the GSK Territory;

          (f) it has no knowledge that any Third Party is infringing the Abbott
or Myogen Patent Rights in the GSK Territory in a manner that could reasonably
be believed to have a material adverse effect on the making, having made, use,
sale, offering for sale, and importation of Product in the Field in the GSK
Territory pursuant to this Agreement;

          (g) except as otherwise disclosed to GSK or in Myogen's filings with
the Securities and Exchange Commission, it has no knowledge of the existence of
any data or information indicating that there are quality, toxicity, safety
and/or efficacy concerns which would materially impair the utility and/or safety
of the Product in the Field; and

          (h) to the best of Myogen's knowledge, the Abbott Agreement remains in
full force and effect and Myogen is in compliance in all material respects with
the terms of the Abbott Agreement, a complete copy of which is attached hereto
as Exhibit A.

     Section 12.3 Covenants of Myogen.

          (a) Myogen covenants that it will not at any time during the Term,
encumber any of its Confidential Information, the Myogen Know-How, Abbott
Know-How, Myogen Patent Rights or Abbott Patent Rights with liens, mortgages,
security interests, charges, or otherwise in any manner that could reasonably be
believed to have a material adverse effect on GSK's rights to Develop,
Manufacture and/or Commercialize Product in the Field in the GSK Territory.

          (b) Myogen covenants that it will not knowingly take or omit to take
any actions that would constitute a material breach of the Abbott Agreement,
which breach would be reasonably likely to have a material adverse effect on
GSK's rights to Develop, Manufacture and/or Commercialize the Product in the
Field in the GSK Territory.

     Section 12.4 Covenants of GSK.

          (a) GSK covenants that it will not at any time during the Term,
encumber any

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


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of its Confidential Information, the GSK Know-How, Myogen Know-How, Abbott
Know-How, GSK Patent Rights, Myogen Patent Rights or Abbott Patent Rights with
liens, mortgages, security interests, charges, or otherwise in any manner that
could reasonably be believed to have a material adverse effect on Myogen's
rights to Develop, Manufacture and/or Commercialize Product in the Field in the
Territory.

          (b) GSK covenants that it will not knowingly take or omit to take any
actions that would constitute a material breach of the Abbott Agreement, which
breach would be reasonably likely to have a material adverse effect on Myogen's
rights to Develop, Manufacture and/or Commercialize the Product in the
Territory.

          (c) Notwithstanding any other provisions contained in this Agreement,
GSK hereby consents to Myogen conducting the ARIES-3 study in the Territory at
such locations as are selected by Myogen in conjunction with the Joint Project
Team and acknowledges that no further consents or approvals are required from
GSK with respect to the conduct of such study in the GSK Territory so long as
the study is conducted in a manner consistent in all material respects with
description of the study contained in the Development Plan.

     Section 12.5 Compliance with Laws.

          (a) GSK covenants and agrees to comply, and to cause its Affiliates
and any Sublicensees to comply, with all Applicable Laws with respect to the
Development, Manufacture and Commercialization of the Product in the Field in
the GSK Territory, and with respect to the Manufacture and exportation of
Product in the Myogen Territory.

          (b) Myogen covenants and agrees to comply, and to cause its Affiliates
to comply, with all Applicable Laws with respect to the Development, Manufacture
and Commercialization of the Product in the Field in the Myogen Territory.

     Section 12.6 Limitation of Warranty. EXCEPT AS EXPRESSLY STATED IN THIS
ARTICLE 12, NEITHER PARTY MAKES ANY OTHER REPRESENTATION OR WARRANTY, AND EACH
PARTY EXPRESSLY DISCLAIMS ALL IMPLIED WARRANTIES, INCLUDING WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, WITH
RESPECT TO ANY PRODUCT, MATERIALS, INFORMATION, SERVICES OR LICENSES PROVIDED TO
THE OTHER PARTY PURSUANT TO THIS AGREEMENT.

                                  ARTICLE XIII

                            CONFIDENTIAL INFORMATION

          Section 13.1 Confidential Information. Myogen and GSK each hereby
recognize and acknowledge that the other Party's Confidential Information
constitutes valuable and confidential information. Subject to other express
provisions of this Agreement, Myogen and GSK each agree that during the Term,
and for a period of five (5) years after the effective date of the expiration or
earlier termination of this Agreement for any reason.

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


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          (a) The Parties will not disclose, directly or indirectly, in any
manner whatsoever to any Third Parties any Confidential Information received
from the other Party (the "Disclosing Party") without first obtaining the
written consent of the Disclosing Party, and the other Party ("Recipient") will
keep confidential, all of the Disclosing Party's Confidential Information that
is disclosed to Recipient. Recipient agrees to use the same level of care in
safeguarding the Disclosing Party's Confidential Information that Recipient uses
with its own confidential information of a similar nature, but in no event less
than reasonable care. Recipient will restrict disclosure of the Disclosing
Party's Confidential Information solely to those of its (or its Affiliate's)
employees or representatives having a need to know such Confidential Information
in order to exercise a right granted or fulfill an obligation under, this
Agreement.

          (b) Both Parties shall ensure that each of their respective employees
and representatives who will have access to the Confidential Information of the
Disclosing Party are bound by an agreement to maintain such Confidential
Information in accordance with the confidentiality obligations set forth in this
Article XIII.

          (c) Recipient will not use the Disclosing Party's Confidential
Information in any manner whatsoever other than solely in connection with the
performance of its obligations, or exercise of its rights, under this Agreement.

          (d) Except as permitted by this Article XIII, or as otherwise required
by Applicable Law, and subject to section 14.10 of the Abbott Agreement, Myogen
and GSK each agree not to disclose any terms or conditions of this Agreement or
the existence of this Agreement to any Third Party without the prior written
consent of the other Party, provided, that each Party will be entitled to
disclose the terms of this Agreement without such consent to its advisors and
potential investors or other financing sources, to bona fide potential
investors, lenders and acquirors/acquirees, and to such Party's consultants and
advisors, and to its permitted licensees and Sublicensees on the condition that
such Persons agree to keep such Confidential Information in accordance with the
obligations set forth in this Article XIII.

          (e) In the event Recipient is requested pursuant to, or required by,
Applicable Law to disclose any of the Disclosing Party's Confidential
Information, it will notify the Disclosing Party promptly so that the Disclosing
Party may seek a protective order or other appropriate remedy or, in the
Disclosing Party's sole discretion, waive compliance with the confidentiality
provisions of this Agreement. At the Disclosing Party's expense, Recipient will
co-operate in all reasonable respects, in connection with any reasonable actions
to be taken for the foregoing purpose. In the event that no such protective
order or other remedy is obtained, or that the Disclosing Party waives
compliance with the confidentiality provisions of this Agreement, Recipient
will, without liability hereunder, furnish only that portion of the Confidential
Information which Recipient is advised by its counsel is legally required, and
Recipient will exercise reasonable efforts to obtain reliable assurances that
confidential treatment will be accorded the Disclosing Party's Confidential
Information.

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


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          (f) Upon the effective date of the termination of this Agreement for
any reason, either Party may request in writing, and the other Party will
either: (i) promptly destroy all copies of the requesting Party's Confidential
Information in the possession of the other Party and confirm such destruction in
writing to the requesting Party; or (ii) promptly deliver to the requesting
Party, at the other Party's expense, all copies of such Confidential Information
in the possession of the other Party, provided, however, the other Party will be
permitted to retain one (1) copy of the requesting Party's Confidential
Information for the sole purpose of determining any continuing obligations
hereunder. Additionally, upon termination of this Agreement for any reason, both
Parties will immediately cease all use of the other Party's Confidential
Information including, to the extent reasonably possible, removing all
references to such Confidential Information from its internal analyses,
memoranda, compilations, studies or other documents; provided however, that GSK
will be permitted to continue using Myogen's Confidential Information after
termination of this Agreement in the exercise of its rights under Section
11.9(a)(vi) and Myogen will be permitted to continue using GSK's Confidential
Information after termination of this Agreement in the exercise of its rights
under Section 11.9. For the avoidance of doubt, GSK will be permitted to
continue using Myogen's Confidential Information after the expiration of this
Agreement in the exercise of its rights pursuant to Section 11.1 and will not be
obligated to return such Confidential Information of Myogen in accordance with
this Section 13.1(f). All Confidential Information will continue to be subject
to the terms of this Agreement for the period set forth in this Section 13.1.

          (g) Each Party represents and warrants to the other Party that it has
all right, title and ownership interest in and to its Confidential Information
and/or it has the right to disclose its Confidential Information to the other
Party. Each Party may seek to enforce all rights and legal remedies available
under this Article XIII or by law, including injunctive relief, specific
performance and other equitable remedies in the event of a breach of the
provisions of this Article XIII by the other Party.

          (h) Notwithstanding the provisions of this Article XIII, the Parties
agree that nothing contained in this Article XIII will prevent GSK, in any way
whatsoever from disclosing any Myogen Confidential Information, without
obtaining Myogen's prior consent, to any Affiliate of GSK or to any Third Party
for the purposes of engaging in the Development, Manufacture and/or
Commercialization of Product in the Field in the GSK Territory, provided such
Affiliate or Third Party is under an obligation of confidentiality at least as
restrictive as the obligations contained in Article XIII herein with respect to
the Confidential Information. The confidentiality obligations set forth in this
Article XIII will supersede the Confidential Disclosure Agreement dated as of
January 20, 2005 between the Parties ("Confidentiality Agreement"), and will
govern any and all information disclosed by either Party to the other pursuant
thereto, and will be retroactively effective to the date of the Confidentiality
Agreement.

     Section 13.2 Publicity. Subject to the terms and conditions of the Abbott
Agreement, including section 14.10 thereof, any key announcements or publicity
regarding the existence of this Agreement or any terms or subject matter of this
Agreement by either Myogen and/or GSK will be agreed to by Myogen and GSK in
writing in advance of any such announcement or publicity. The Party preparing
any such announcement, publicity or press release will provide the other Party
with a draft thereof reasonably in advance of disclosure so as to permit the
other Party to review and comment on such announcement, publicity or press
release, unless

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


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applicable law, rule or regulation otherwise requires immediate public
disclosure. The foregoing notwithstanding, the Parties will agree on a press
release to announce the execution of this Agreement, together with a
corresponding question/answer outline for use in responding to inquiries about
this Agreement. Thereafter, Myogen and GSK may each disclose to Third Parties
the information contained in such press release and question/answer outline
without the need for further approval by the other Party. Each Party agrees that
it will co-operate fully with the other with respect to all disclosures
regarding this Agreement to the Securities Exchange Commission and any other
governmental or regulatory agencies, including requests for confidential
treatment of proprietary information of either Party included in any such
disclosure.

     Section 13.3 Publication.

          (a) Myogen will not submit for written, electronic or oral publication
in any country in the Territory, any document, manuscript, abstract or the like
(a "Myogen Publication") which includes any data, results or any other
information regarding, related to, Product in the Field without first providing
GSK with a copy of such Myogen Publication for GSK's review. GSK will review and
provide its comments and changes, if any, to such Myogen Publication which is an
abstract, within five (5) Business Days after receipt of the Myogen Publication
from Myogen and to such Myogen Publication which is a manuscript or any other
document, within twenty (20) Business Days after receipt of the Myogen
Publication from Myogen, provided that GSK will review and provide its comments
and changes, if any, to any abstract within five (5) Business Days after receipt
for GSK's review and to any manuscript or any other publication, within twenty
(20) Business Days after receipt for GSK's review. Myogen will consider in good
faith any comments and changes received from GSK as provided herein with respect
to such Myogen Publication. Any GSK contributions will be acknowledged in any
such Myogen Publication.

          (b) GSK will not submit for written, electronic or oral publication in
any country in the Territory, any document, manuscript, abstract or the like (a
"GSK Publication") which includes any data, results or any other information
regarding, related to, Product in the Field without first providing Myogen with
a copy of such GSK Publication for Myogen's review. Myogen will review and
provide its comments and changes, if any, to such GSK Publication which is an
abstract, within five (5) Business Days after receipt of the GSK Publication
from GSK and to such GSK Publication which is a manuscript or any other
document, within twenty (20) Business Days after receipt of the GSK Publication
from GSK, provided that Myogen will review and provide its comments and changes,
if any, to any abstract within five (5) Business Days after receipt for Myogen's
review and to any manuscript or any other publication, within twenty (20)
Business Days after receipt for Myogen's review. GSK will consider in good faith
any comments and changes received from GSK as provided herein with respect to
such GSK Publication. Any Myogen contributions will be acknowledged in any such
GSK Publication.

     Section 13.4 Clinical Trial Registries. The Parties acknowledge and agree
that notwithstanding anything to the contrary contained in this Article XIII,
each Party may publish the results and/or summaries of clinical trials relating
to Compound and/or Product on a clinical trial register maintained by such Party
or its Affiliate and the protocols of clinical trials relating

[..**..] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED
BY BRACKETS, HAS BEEN OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
EXCHANGE COMMISSION PURSUANT TO RULE 24B-2 OF THE SECURITIES EXCHANGE ACT OF
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to Compound and/or Product on www.ClinicalTrials.gov (and/or in each case
publish the results, summaries and/or protocols of clinical trials on such other
websites and/or repositories as required by Applicable Law or such Party's or
its Affiliate's standard operating procedures), and that each such publication
will not be a breach of the confidentiality obligations provided in this Article
XIII, provided that the publishing Party first advises the Joint Steering
Committee of such publication. Each Party agrees to cooperate with the other
Party in such effort, including using Commercially Reasonable Efforts to provide
the publishing Party with the protocols, results, data, and other information
relating to all clinical trials conducted by the non-publishing Party relating
to the Product in such Party's possession that the publishing Party reasonably
requires to be published on the publishing Party's clinical trial register,
www.ClinicalTrials.gov, or such other websites or repositories as may be
required by Applicable Law or the publishing Party's standard operating
procedures.

                                   ARTICLE XIV

                     DISPUTE RESOLUTION AND INDEMNIFICATION

     Section 14.1 Dispute Resolution. Except with regard to any matters which
are to be resolved as set forth in Section 3.1(d) and Section 3.4, if a dispute
or controversy regarding any right or obligation under this Agreement, arises
between the Parties which they are unable to resolve (a "Dispute"), each of the
Parties will, within a reasonable amount of time after any such Dispute arises
after such Dispute arises (or in the event that there is a cure period as set
forth in Sections 6.2(a), 6.2(b) or 11.2, within a reasonable amount of time
after the expiration of the applicable cure period), be entitled to submit to
the other Party written notice of such Dispute, with such notice setting forth
in reasonable detail the nature of the Dispute (the "Dispute Notice"). For a
period of thirty (30) days after the date of the receiving Party's receipt of
the Dispute Notice, the Parties will seek to resolve such Dispute by good faith
negotiation between the president of pharmaceuticals for Europe at GSK or
his/her designee and chief executive officer of Myogen or his/her designee. If
at the end of such thirty (30) day period the Dispute remains unresolved, the
Parties may seek relief for such Dispute using any appropriate administrative or
judicial mechanism which may be available. The provisions of this Section 14.1
will not restrict in any way the Parties' rights to seek preliminary injunctive
or other equitable relief from any court having jurisdiction.

     Section 14.2 GSK Indemnification Obligations. GSK will indemnify, defend
and hold harmless Myogen, its Affiliates, and their respective officers,
directors, trustees, agents, employees and Sublicensees (collectively, "Myogen
Indemnitees") from and against any and all losses, liabilities, claims,
obligations, demands, awards, settlements, penalties, fines, suits, damages,
costs (including costs of investigation, defense and enforcement of this
Agreement), fees, taxes, and expenses, including reasonable attorneys' fees,
experts' fees and expenses, involving a claim or action of a Third Party
(collectively, "Losses"), incurred or suffered by the Myogen Indemnitees by
reason of, arising out of or in connection with:

          (a) the negligent, reckless or willful actions or omissions of GSK,
its Affiliates, or Sublicensees in performing GSK's obligations under this
Agreement;

[..**..] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED
BY BRACKETS, HAS BEEN OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
EXCHANGE COMMISSION PURSUANT TO RULE 24B-2 OF THE SECURITIES EXCHANGE ACT OF
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          (b) the material breach of any covenant, warranty or representation
made by GSK under this Agreement;

          (c) the Development, Manufacture and/or Commercialization of Product
in the Field in the GSK Territory or the Manufacture by GSK, its Affiliate or
Sublicensee of the Product in the Field in the Myogen Territory; and/or

          (d) any violation of Applicable Law by GSK in the performance of any
of GSK's obligations under this Agreement;

provided, however, except in each case to the extent that such Loss is
attributable to any matter for which Myogen is obligated to indemnify a GSK
Indemnitee as provided in section 14.3 below.

     Section 14.3 Myogen Indemnification Obligations. Myogen will indemnify,
defend and hold harmless GSK, its Affiliates, and their respective officers,
directors, trustees, agents, employees and Sublicensees (collectively, "GSK
Indemnitees"), from and against any and all Losses incurred or suffered by the
GSK Indemnitees or any of them, by reason of, arising out of or in connection
with:

          (a) the negligent, reckless or willful actions or omissions of Myogen
in performing Myogen's obligations under this Agreement;

          (b) the material breach of any covenant, warranty or representation
made by Myogen under this Agreement;

          (c) the Development, Manufacture (other than by GSK, its Affiliate or
Sublicensee), and/or Commercialization of Product in the Field in the Myogen
Territory or outside the Field in the Territory;

          (d) the Development, Manufacture and/or Commercialization of Compound
and/or Product in the Territory after the effective date of the termination of
this Agreement for any reason, except to the extent attributable to an act or
omission, at any time, by GSK, its Affiliates or licensees;

          (e) any violation of Applicable Law by Myogen in the performance of
any of Myogen's obligations under this Agreement; and/or

          (f) the Abbott Agreement, except to the extent attributable to a
default or breach of this Agreement by GSK, its Affiliates or licensees;

provided, however, to the extent attributable to any matter for which GSK is
obligated to indemnify a Myogen Indemnitee as provided in section 14.2 above.

     Section 14.4 Indemnity Procedures. A Person entitled to indemnification
pursuant to either Section 14.2 or Section 14.3 will hereinafter be referred to
as an "Indemnitee." A Party

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


                                       65

<PAGE>

obligated to indemnify an Indemnitee hereunder will hereinafter be referred to
as an "Indemnitor." In the event an Indemnitee is seeking indemnification under
either Section 14.2 or Section 14.3, the Indemnitee will inform the Indemnitor
of a claim as soon as reasonably practicable after it receives notice of the
claim, it being understood and agreed that the failure by an Indemnitee to give
notice of a Third Party claim as provided in this Section 14.4. will not relieve
the Indemnitor of its indemnification obligation under this Agreement except and
only to the extent that such Indemnitor is actually prejudiced as a result of
such failure to give notice. The Indemnitee will permit the Indemnitor to assume
direction and control of the defense of the claim (including, subject to this
Section 14.4, the right to settle the claim solely for monetary consideration),
and, at the Indemnitor's expense, will co-operate as reasonably requested in the
defense of the claim. The Indemnitee will have the right to retain its own
counsel at its own expense; provided, that, if the Indemnitor assumes control of
such defense and the Indemnitee reasonably concludes, based on advice from
counsel, that the Indemnitor and the Indemnitee have conflicting interests with
respect to such action, suit, proceeding or claim, the Indemnitor will be
responsible for the reasonable fees and expenses of counsel to the Indemnitee
solely in connection therewith. The Indemnitor may not settle such action or
claim, or otherwise consent to an adverse judgment in such action or claim,
which would subject the Indemnitee to an injunction or if such settlement or
judgment would materially diminish or limit or otherwise adversely affect the
rights, activities or financial interests of the Indemnitee, without the express
written consent of the Indemnitee.

     Section 14.5 No Punitive or Exemplary Damages. NOTWITHSTANDING ANYTHING TO
THE CONTRARY, EXCEPT WITH RESPECT TO THE INDEMNIFICATION OBLIGATIONS UNDER
SECTIONS 14.2 AND 14.3, IN NO EVENT WILL EITHER PARTY, ITS DIRECTORS, TRUSTEES,
OFFICERS, EMPLOYEES, AGENTS OR AFFILIATES BE LIABLE TO THE OTHER PARTY FOR ANY
PUNITIVE OR EXEMPLARY DAMAGES, WHETHER BASED UPON A CLAIM OR ACTION OF CONTRACT,
WARRANTY, NEGLIGENCE, STRICT LIABILITY OR OTHER TORT, OR OTHERWISE, ARISING OUT
OF THIS AGREEMENT.

     Section 14.6 Insurance. Myogen hereby represents that it is insured for
products liability and general liability, and that it has and will maintain
those coverages for the Term in amounts that are in accord with reasonable
practices in the consumer healthcare industry for products such as Product. GSK
hereby represents that it is self-insured for products liability and general
liability, and that it has and will maintain those coverages for the Term in
amounts that are in accord with reasonable practices in the consumer healthcare
industry for products such as Product.

                                   ARTICLE XV

                                  MISCELLANEOUS

     Section 15.1 Notices. Notices required or permitted under this Agreement
will be in writing and sent by prepaid registered or certified air mail or by
overnight express mail (e.g., FedEx), or by facsimile confirmed by prepaid
registered or certified air mail letter or by

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


                                       66

<PAGE>

overnight express mail (e.g., FedEx), (failure of such confirmation will not
affect the validity of such notice by facsimile to the extent the receipt of
such notice is confirmed by the act of the receiving Party (e.g., a facsimile of
the receiving Party submitting its receipt of such notice)) and will be deemed
to have been properly served to the addressee upon receipt of such written
communication, to the following addresses of the Parties:

     If to GSK:

          Glaxo Group Limited
          Glaxo Wellcome House, Berkeley Avenue,
          Greenford, Middlesex, UB6 0NN, England
          Attention: Company Secretary
          Facsimile: +44 208 047 6905

     with a copy to:

          Smith Kline Beecham Corporation d/b/a GlaxoSmithKline
          2301 Renaissance Boulevard
          King of Prussia, PA 19406-2772
          Attention: Vice President and Associate General Counsel, R&D Legal
          Operations, Business Development Transactions Team
          Facsimile: 610-787-7084

     If to Myogen:

          Myogen, Inc.
          7575 West 103rd Ave., Suite 102
          Westminster, CO 80021
          Attn: Chief Executive Officer

     with a copy to:

          Myogen, Inc.
          7575 West 103rd Ave., Suite 102
          Westminster, CO 80021
          Attn: General Counsel

     Section 15.2 Governing Law. The form, execution, validity, construction and
effect of this Agreement will be governed by and construed in accordance with
the laws of the State of New York, without regard to the choice-of-law
provisions thereof. The Parties hereby consent to service of process by mailing
or delivering such service to the Party at its respective principal business
address. The Parties hereby submit to the jurisdiction of the federal courts in
the State of New York for the resolution of any Disputes through any judicial
mechanism.

     Section 15.3 Performance by Affiliates. The Parties recognize that each
Party may perform some or all of its obligations under this Agreement through
Affiliates; provided,

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


                                       67

<PAGE>

however, that each Party will remain responsible for the performance by its
Affiliates and will cause its Affiliates to comply with the provisions of this
Agreement in connection with such performance. Each Party hereby expressly
waives any requirement that the other Party exhaust any right, power or remedy,
or proceeds against an Affiliate, for any obligation or performance hereunder
prior to proceeding directly against such Party.

     Section 15.4 Miscellaneous.

          (a) Binding Effect. This Agreement will be binding upon and inure to
the benefit of the Parties and their respective legal representatives,
successors and permitted assigns.

          (b) Headings. Paragraph headings are inserted for convenience of
reference only and do not form a part of this Agreement.

          (c) Counterparts. This Agreement may be executed simultaneously in two
(2) or more counterparts, each of which will be deemed an original.

          (d) Entire Agreement; Amendment; Waiver. This Agreement, and any
applicable provisions of the Abbott Agreement, constitutes the entire
understanding of the Parties with respect to the subject matter hereof and
supersedes all previous writings and understandings, including the
Confidentiality Agreement. This Agreement may be amended, modified, superseded
or cancelled, and any of the terms may be waived, only by a written instrument
executed by each Party or, in the case of waiver, by the Party waiving
compliance. No waiver by any Party of any condition or of the breach of any term
contained in this Agreement, whether by conduct, or otherwise, in any one or
more instances, will be deemed to be, or considered as, a further or continuing
waiver of any such condition or of the breach of such term or any other term of
this Agreement.

          (e) No Third Party Beneficiaries. No Third Party, including any
employee of any Party to this Agreement, will have or acquire any rights by
reason of this Agreement.

          (f) Assignment and Successors. Neither this Agreement nor any interest
hereunder will be assigned, sold, transferred or otherwise disposed of by either
Party without the prior written consent of the other Party, provided, however,
that either Party may assign this Agreement to its Affiliate or to any
corporation with which such Party may merge or consolidate, or to which it may
transfer all or substantially all of its business or assets associated with this
Agreement, without obtaining the consent of the other Party. Any attempted
assignment, sale or transfer in violation of the prior sentence will be void.

          (g) Force Majeure. Neither Myogen nor GSK will be liable for failure
of or delay in performing obligations set forth in this Agreement (other than
the payment of amounts owed), and neither will be deemed in breach of its
obligations, if such failure or delay is due to natural disasters or any causes
reasonably beyond the control of Myogen or GSK (a "Force Majeure Event"). When a
Force Majeure Event arises, the Parties will discuss what, if any, modification
of the terms of this Agreement may be required in order to arrive at an
equitable solution.

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


                                       68

<PAGE>

          (h) Severability. If any provision of this Agreement is or becomes
invalid or is ruled invalid by any court of competent jurisdiction or is deemed
unenforceable, such provision shall be considered severed from this Agreement,
and it is the intention of the Parties that the remainder of the Agreement will
not be affected. The Parties shall make a good faith effort to replace any
invalid or unenforceable provision with a valid and enforceable one such that
the objectives contemplated by the Parties when entering this Agreement may be
realized.

          (i) Further Actions. Each Party agrees to execute, acknowledge and
deliver such further instruments, and to do all such other commercially
reasonable acts, as may be necessary or appropriate in order to carry out the
purposes and intent of this Agreement.

          (j) Relationship of the Parties. It is not the intent of the Parties
hereto to form any partnership or joint venture. Each Party will, in relation to
its obligations hereunder, be deemed to be and will be an independent
contractor, and nothing in this Agreement will be construed to give such Party
the power or authority to act as agent for the other Party for any purpose, or
to bind or commit the other Party in any way whatsoever.

            [The remainder of this page is intentionally left blank.]

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


                                       69

<PAGE>

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

GLAXO GROUP LIMITED                     MYOGEN, INC.


By: /s/ Richard Stephens                By: /s/ J. William Freytag
    ---------------------------------       ------------------------------------
Name: Richard Stephens                  Name: J. William Freytag, Ph.D.
Title: Assistant Company Secretary      Title: CEO & President

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


                                       70

<PAGE>

                                    EXHIBIT A

                                ABBOTT AGREEMENT

See Exhibit 10.18 to the registrant's Registration Statement on Form S-1 (File
No. 333-108301) and amendments thereto, declared effective October 29, 2003,
which is incorporated herein by reference.

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


                                       71
<PAGE>

                                    EXHIBIT B

                              ABBOTT PATENT RIGHTS

<TABLE>
<CAPTION>
ABBOTT PATENTS INCLUDED IN THE AMBRISENTAN LICENSE AGREEMENT
------------------------------------------------------------
FILE NO.       APP. NO.          COUNTRY        PATENT NO.    ISSUE DATE  FAMILY  FILING DATE    EXPIRE       STATUS
--------  ------------------  -------------  ---------------  ----------  ------  -----------  ---------  -------------
<S>       <C>                 <C>            <C>              <C>         <C>     <C>          <C>        <C>
 43997    WO 94/25442         PCT                                           1        4/13/94   2014
 43997    94913588.3          Europe             695,295        3/8/02      1        4/13/94   2014
 43997    94/065681           Australia         000678236       5/22/97     1        4/13/94   2014
 43997    94913588.3          Austria           000695295       3/8/02      1        4/13/94   2014
 43997    950669              Belarus             4309          6/28/01     1        4/13/94   2014
 43997    94913588.3          Belgium           000695295       3/8/02      1        4/13/94   2014
 43997    PI9406478-4         Brazil                                        1        4/13/94   2014
 43997    2160912             Canada                                        1        4/13/94   2014
 43997    94191867.X          China               67981         5/23/01     1        4/13/94   2014
 43997    95/PV2768           Czech Rep.         291468         1/14/03     1        4/13/94   2014
 43997    94913588.3          Denmark           000695295       3/8/02      1        4/13/94   2014
 43997    954994              Finland            113650         5/31/04     1        4/13/94   2014
 43997    94913588.3          France            000695295       3/8/02      1        4/13/94   2014
 43997    P4313412.2          Germany                                       1        4/23/93   2014
 43997    059410072           Germany           59410072        3/6/02      1        4/13/94   2014
 43997    94913588.3          Greece            000695295       3/8/02      1        4/13/94   2014
 43997    9503040             Hungary           000221475      10/28/02     1        4/13/94   2014
 43997    94913588.3          Ireland           000695295       3/8/02      1        4/13/94   2014
 43997    94913588.3          Italy             000695295       3/8/02      1        4/13/94   2014
 43997    94/521408           Japan              3483254        1/6/04      1        4/13/94   2014
 43997    971746.1            Kazakhstan        000008733       6/29/99     1        4/13/94   2014
 43997    95/704618           Korea             000325555       7/27/02     1        4/13/94   2014
 43997    94913588.3          Luxembourg        000695295       3/8/02      1        4/13/94   2014
 43997    94913588.3          Netherlands       000695295       3/8/02      1        4/13/94   2014
 43997    265275              New Zealand       000265275       7/24/97     1        4/13/94   2014
 43997    954211              Norway            000307087       2/7/00      1        4/13/94   2014
 43997    P311228             Poland            000179463       9/29/00     1        4/13/94   2014
 43997    94913588.3          Portugal          000695295       3/8/02      1        4/13/94   2014
 43997    95120099            Russia Fed.       002140413       4/28/99     1        4/13/94   2014
</TABLE>

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


                                       72

<PAGE>

<TABLE>
<S>       <C>                 <C>            <C>              <C>         <C>     <C>          <C>        <C>
 43997    94913588.3          Spain             000695295       3/8/02      1        4/13/94   2014
 43997    94913588.3          Sweden            000695295       3/8/02      1        4/13/94   2014
 43997    94913588.3          Switzerland       000695295       3/8/02      1        4/13/94   2014
 43997    95114907            Ukraine           000039885       3/21/01     1        4/13/94   2014
 43997    94913588.3          United King.      000695295       3/8/02      1        4/13/94   2014

 44751    WO 95/26716         PCT                                           2        3/31/94
 44751    95914301.7          Europe             752854         8/22/01     2        3/23/95   2015
 44751    95914301.7          Austria            752854         8/22/01     2        3/23/95   2015
 44751    9521356             Australia          695193        11/19/98     2        3/23/95   2015
 44751    95914301.7          Belgium            752854         8/22/01     2        3/23/95   2015
 44751    960810              Belarus             4894          9/3/02      2        3/23/95   2015
 44751    PI1100434-7         Brazil                                        2        12/4/97                 pending
 44751    2,186,784           Canada                                        2        3/23/95                 pending
 44751    95193167            China             95193167        9/21/01     2        3/23/95   2015
 44751    481/95              Chile               40272        11/22/99     2        3/23/95   2014
 44751    950515A             Croatia            P950115        12/5/01     2        3/9/95    2015
 44751    962873              Czech Rep.         290684         7/19/02     2        3/23/95   2015
 44751    95914301.7          Denmark            752854         8/22/01     2        3/23/95   2015
 44751    963885              Finland                                       2        3/23/95                 pending
 44751    95914301.7          France             752854         8/22/01     2        3/23/95   2015
 44751    P4411225.4          Germany                                       2        3/31/94                  lapsed
 44751    752854              Germany          59509537.2       9/27/01     2        3/23/15   2015
 44751    P9602695            Hungary                                       2        3/23/95                 pending
 44751    P-950504            Indonesia         ID0007872       5/1/02      2        3/30/95   2015
 44751    95914301.7          Ireland            752854         8/22/01     2        3/23/95   2015
 44751    113137              Israel             113137         1/30/00     2        3/27/95   2015
 44751    95914301.7          Italy              752854         8/22/01     2        3/23/95   2015
 44751    95/525391           Japan                                         2        3/23/95                 pending
 44751    961760              Kazakhstan          11055        10/15/01     2        3/23/95   2015
 44751    96/705420           Korea              365629         12/9/02     2        3/23/95   2015
 44751    95914301.7          Luxembourg         752854         8/22/01     2        3/23/95   2015
 44751    964448              Mexico             196039         4/14/00     2        3/23/95   2015
 44751    283333              New Zealand        283333                     2        3/23/95   2015
 44751    95914301.7          Netherlands        752854         8/22/01     2        3/23/95   2015
 44751    964121              Norway             310497         7/16/01     2        7/16/01   2015
</TABLE>

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


                                       73

<PAGE>

<TABLE>
<S>       <C>                 <C>            <C>              <C>         <C>     <C>          <C>        <C>
 44751    95-50220            Philippines     1-1995-50220      8/21/01     2        3/29/95   2018
 44751    95914301.7          Portugal           752854         8/22/01     2        3/23/95   2015
 44751    316563              Poland             179580         3/30/00     2        3/23/95   2015
 44751    96121628            Russia Fed.        216308         3/10/01     2        3/23/95   2015
 44751    9612382-3           Singapore           51274         4/18/00     2        3/23/95   2015
 44751    9520048             Slovenia           9520048        3/3/97      2        3/23/95   2015
 44751    95914301.7          Spain              752854         8/22/01     2        3/23/95   2015
 44751    95914301.7          Sweden             752854         8/22/01     2        3/23/95   2015
 44751    95914301.7          Switzerland        752854         8/22/01     2        3/23/95   2015
 44751    952614              South Africa       9502614       11/27/96     2        3/30/95   2015
 44751    84103012            Taiwan            NI-111879       2/21/00     2        3/28/95   2015
 44751    96104109            Ukraine             44734         3/15/02     2        3/23/95   2015
 44751    95914301.7          United King.       752854         8/22/01     2        3/23/95   2015

 45281    WO 96/11914         PCT                                           3        10/7/95
 45281    95 935 916.7        Europe             785926         8/22/01     3        10/7/95   2015
 50588    01 103 889.0        Europe             1110952        9/29/04     3        10/7/95   2015
 45281    254585              Argentina          254585M       10/24/00     3        10/7/95   2015
 45281    95935916.7          Austria            785926         8/27/01     3        8/27/01   2015
 45281    95/038045           Australia          688611         7/2/98      3        10/7/95   2015
 45281    95935916.7          Belgium            785926         8/27/01     3        10/7/95   2015
 45281    PI1100950-0         Brazil                                        3       11/26/97                 pending
 45281    2201785             Canada                                        3        10/7/95                 pending
 45281    1564/95             Chile               40061        11/15/99     3        7/6/05    2014
                                                                                                          reexamination
 45281    ZL95195655.8        China           ZL95195655.8      3/24/04     3        10/7/95   10/7/2015      filed
                                                                                                           published as
 45281    200410002783.3      China-Div.                                    3        10/7/95                CN1513844A
 45281    P950517A            Croatia            P950517        5/21/04     3       10/13/95   2015
 45281    P20040364A          Croatia                                       3       10/13/95                 pending
 45281    PV 1997-1132        Czech Rep.         294603         1/1/05      3        10/7/95   2015
 45281    95935916.7          Denmark            785926         8/27/01     3        10/7/95   2015
 45281    971529              Finland                                       3        10/7/95                 pending
 45281    1103889             France             1110952        9/29/04     3        10/7/95   2015
 45281    95935916.7          France             785926         8/27/01     3        10/7/95   2015
 45281    P4436851.8          Germany                                       3       10/14/94
 45281    95935916.7          Germany           59509541        8/27/01     3        10/7/95   2015
</TABLE>

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


                                       74

<PAGE>

<TABLE>
<S>       <C>                 <C>            <C>              <C>         <C>     <C>          <C>        <C>
 45281    01 103 889.0        Germany          59510949.7       9/29/04     3        10/7/95   2015
 45281    95935916.7          Great Britain      785926         8/27/01     3        10/7/05   2015
 45281    01 103 889.0        Great Britain      1103889        9/29/04     3        10/7/95   2015
 45281    95935916.7          Greece             785926         8/27/01     3        10/7/95   2015
 45281    4109463.5           Hong Kong                                     3                               published
 45281    P9701975            Hungary            220621         5/15/02     3        10/7/95   2015
 45281    P952110             Indonesia         ID0007942       5/22/02     3        10/7/95   2015
 45281    95935916.7          Ireland            785926         8/27/01     3        10/7/95   2015
 45281    01 103 889.0        Ireland            1110952        9/29/04     3        10/7/95   2015
 45281    115560              Israel             115560         6/15/03     3        10/7/95   2015
 45281    95935916.7          Italy              785926         8/27/01     3        10/7/95   2015
 45281    01 103 889.0        Italy              1110952        9/29/04     3        10/7/95   2015
 45281    96/512911           Japan                                         3        10/7/95                 pending
 45281    97/702413           Korea             10-438339       6/22/04     3        10/7/95   2015
 45281    95935916.7          Luxembourg         785926         8/27/01     3        10/7/95   2015
 45281    972658              Mexico             196772         6/1/01      3        10/7/95   2015
 45281    95935916.7          Netherlands        785926         8/27/01     3        10/7/95   2015
 45281    294849              New Zealand        294849         8/11/99     3        10/7/95   2015
 45281    19971675            Norway             308846         11/6/00     3        10/7/95   2015
 45281    051474              Philippines     1-1995-51474      5/7/02      3       10/13/95   2019
 45281    P319655             Poland             186850         9/4/05      3        10/7/95   2015
 45281    95935916.7          Portugal           785926         8/27/01     3        10/7/95   2015
 45281    97107617            Russia Fed.        2180335        3/10/02     3        10/7/95   2015
 45281    9701798-2           Singapore           40930         3/30/99     3        10/7/95   2015
 45281    P9520110            Slovenia           9520110        1/6/98      3        10/7/95   2015
 45281    95/08642            South Africa      95/08642        6/25/97     3       10/13/95   2015
 45281    95935916.7          Spain              785926         8/27/01     3        10/7/95   2015
 45281    01 103 889.0        Spain              1110952        9/29/04     3        10/7/95   2015
 45281    95935916.7          Sweden             785926         8/27/01     3        10/7/95   2015
 45281    84110900            Taiwan             NI97259        2/5/04      3       10/17/95   2015
 45281    028356              Thailand                                      3       10/13/95                 pending
 45281    97052233            Ukraine             45985         5/15/02     3        7/7/95    2015
 45281    95935916.7          United King.       785926         8/27/01     3        10/7/95   2015
 45281    1103889             United King.       1110952        9/29/04     3        10/7/95   2015

480/1171  95395/98            Australia          950755         7/11/02     4        9/10/98   2018
</TABLE>

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


                                       75

<PAGE>

<TABLE>
<S>       <C>                 <C>            <C>              <C>         <C>     <C>          <C>        <C>
480/1171  PI9812531-1         Brazil                                        4        9/10/98                 pending
480/1171  2304712             Canada                                        4        9/10/98                 pending
480/1171  98809545.9          China           ZL98809545.9      2/2/05      4        9/10/98   2018
480/1171  PV2000-1107         Czech Rep.                                    4                                pending
480/1171  98948954.7          Europe             1014989        1/14/04     4        9/10/98   2018
480/1171  98948954.7          France             1014989        1/14/04     4        9/10/98   2018
480/1171  98948954.7          Germany          59810600.6       1/14/04     4        9/10/98   2018
480/1171  P0004298            Hungary                                       4        9/10/98                 pending
480/1171  98948954.7          Italy              1014989        1/14/04     4        9/10/98   2018
480/1171  2000-513571         Japan                                         4                                pending
480/1171  10-2000-7003220     Korea                                         4                                pending
480/1171  2000 002655         Mexico              2654          1/3/05      4        8/5/16    2018
480/1171  20001548            Norway                                        4                                pending
480/1171  2000 110630         Russia Fed.        2222328        1/27/04     4        9/10/98   2018
480/1171  98948954.7          Spain              1014989        1/14/04     4        9/10/98   2018
480/1171  98948954.7          United King.       1014989        1/14/04     4        9/10/98   2018

480/1172  WO 99/16446         PCT                                           5
480/1174  19743140.2          Germany                                       6                                pending

480/1175  PCT/EP/98/05772PCT
480/1175  98945323.8          Europe             1019055        5/7/03      7        9/10/98   2018
480/1175  98945323.8          Austria            1019055        5/7/03      7        9/10/98   2018
480/1175  9267298             Australia          739860         7/2/00      7        9/10/98   2018
480/1175  98945323.8          Belgium            1019055        5/7/03      7        9/10/98   2018
480/1175  PI 9812404-8        Brazil                                        7                                pending
480/1175  2304698             Canada                                        7                                pending
480/1175  98809727.3          China            ZL98809727       5/12/04     7        9/10/98   2018
480/1175  PV1081-2000         Czech Rep.                                    7                                pending
480/1175  98945323.8          Europe             1019055        5/7/03      7        9/10/98   2018
480/1175  19743143.7          Germany                                       7        9/30/97                abandoned
480/1175  98945323.8          Germany          59808297.2       5/7/03      7        9/10/98   2018
480/1175  98945323.8          Finland            1019055        5/7/03      7        9/10/98   2018
480/1175  98945323.8          France             1019055        5/7/03      7        9/10/98   2018
480/1175  01102973.6          Hong Kong         HK1032355       3/4/05      7        4/25/01   2018
</TABLE>

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


                                       76

<PAGE>

<TABLE>
<S>       <C>                 <C>            <C>              <C>         <C>     <C>          <C>        <C>
480/1175  P0004590            Hungary                                       7        9/10/98                 pending
480/1175  98945323.8          Italy              1019055        5/7/03      7        9/10/98   2018
480/1175  10-2000-7003346     Korea                                         7        9/10/98                 pending
480/1175  2000-513580         Japan                                         7                                pending
480/1175  2655                Mexico                                        7        9/10/98                 pending
480/1175  98945323.8          Netherlands        1019055        5/7/03      7        9/10/98   2018
480/1175  20001634            Norway             319048         6/6/05      7        9/10/98   2018
480/1175  2000 11500          Russia Fed.        2213577       10/10/03     7        9/10/98   2018
480/1175  98945323.8          Spain              1019055        5/7/03      7        9/10/98   2018
480/1175  98945323.8          Sweden             1019055        5/7/03      7        9/10/98   2018
480/1175  98945323.8          Switzerland        1019055        5/7/03      7        9/10/98   2018
480/1175  98945323.8          United King.       1019055        5/7/03      7        9/10/98   2018

480/1176  WO 99/17756         PCT                                           8
480/1181  WO 99/29308         PCT                                           9
480/1181  98965685.5          Austria            1035851        8/16/01     9       11/21/98   2018
480/1181  21535/99            Australia          751053         8/8/02      9       11/21/98   2018
480/1181  98965685.5          Belgium            1035851        8/16/01     9       11/21/98   2018
480/1181  PI 9815335-8        Brazil                                        9       11/21/98                 pending
480/1181  2311423             Canada                                        9       11/21/98                 pending
480/1181  98 811 832.7        China            ZL98811832       6/9/04      9       11/21/98   2018
480/1181  2000-2006           Czech Rep.                                    9       11/21/98                 pending
480/1181  98965685.5          Europe             1035851        8/16/01     9       11/21/98   2018
480/1181  98965685.5          Finland            1035851        8/16/01     9       11/21/98   2018
480/1181  98965685.5          France             1035851        8/16/01     9       11/21/98   2018
480/1181  98965685.5          Germany          59801230.3       8/16/01     9       11/21/98   2018
480/1181  01107896.9          Hong Kong         HK1037141       2/25/05     9        6/27/01   2018
480/1181  P0100171            Hungary                                       9       11/21/98                 pending
480/1181  98965685.5          Italy              1035851        8/16/01     9       11/21/98   2018
480/1181  10-2000-7006075     Korea                                         9       11/21/98                 pending
480/1181  2000-523980         Japan                                         9       11/21/98                 pending
480/1181  2000004989          Mexico             220571         5/26/04     9       11/21/98   2018
480/1181  98965685.5          Netherlands        1035851        8/16/01     9       11/21/98   2018
480/1181  20002777            Norway                                        9                                pending
480/1181  2000 117857         Russia Fed.                                   9                                pending
480/1181  98965685.5          Spain              1035851        8/16/01     9       11/21/98   2018
</TABLE>

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


                                       77

<PAGE>

<TABLE>
<S>       <C>                 <C>            <C>              <C>         <C>     <C>          <C>        <C>
480/1181  98965685.5          Sweden             1035851        8/16/01     9       11/21/98   2018
480/1181  98965685.5          Switzerland        1035851        8/16/01     9       11/21/98   2018
480/1181  98965685.5          United King.       1035851        8/16/01     9       11/21/98   2018

 49493    WO 00/026170        PCT                                           10
 49493    2347758             Canada             2347758        9/21/04     10      10/16/99   2019
 49493    99812927.5          China           ZL99812927.5      12/5/01     10      10/16/99   2019
 49493    99949006.3          Germany         59908211.9-0      1/2/04      10      10/16/99   2019
 49493    99949006.3          Europe             1124782        1/2/04      10      10/16/99   2019
 49493    99949006.3          France             1124782        1/2/04      10      10/16/99   2019
 49493    02102528.5          Hong Kong        HK 1040704       5/21/04     10       4/4/02    2019
 49493    P0104010            Hungary                                       10      10/16/99                 pending
 49493    99949006.3          Ireland            1124782        1/2/04      10      10/16/99   2019
 49493    99949006.3          Italy              1124782        1/2/04      10      10/16/99   2019
 49493    142669              Israel                                        10      10/16/99                 pending
 49493    2001-7005389        Korea             10-403905      10/20/03     10     10/16/1999  2019
 49493    2000-579560         Japan                                         10      10/16/99                 pending
 49493    99949006.3          Spain              1124782        1/2/04      10      10/16/99   2019
                              Slovak
 49493    PV0529-2001         Republic           284637         6/6/05      10      10/16/99   2019
 49493    99949006.3          United King.       1124782        1/2/04      10      10/16/99   2019

 51096    PCT/EP01/00322      PCT                                           11
 51096    PCT/EP01/00322      Canada                                        11                               pending
 51096    10002393.2          Germany         50101704.6-08     3/17/04     11       1/12/01   2021
 51096    01902309.2          Europe            1,248,775       3/17/04     11       1/12/01   2021
 51096    1902309.2           France            1,248,775       3/17/04     11       1/12/01   2021
 51096    1902309.2           Ireland           1,248,775       3/17/04     11       1/12/01   2021
 51096    1902309.2           Italy             1,248,775       3/17/04     11       1/12/01   2021
 51096    2001-553756         Japan                                         11       1/12/01                 pending
 51096    2002/007077         Mexico                                        11       1/12/01                 pending
 51096    1902309.2           Spain             1,248,775       3/17/04     11       1/12/01   2021
 51096    1902309.2           United King.      1,248,775       3/17/04     11       1/12/01   2021

 51748    WO 01/24827         PCT                                           12       10/2/00
 51748    2386457             Canada                                        12       10/2/00                 pending
</TABLE>

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


                                       78

<PAGE>

<TABLE>
<S>       <C>                 <C>            <C>              <C>         <C>     <C>          <C>        <C>
 51748    00969395.3          Europe                                        12       10/2/00                 pending
 51748    P0104010            Hungary                                       12       10/2/00                 pending
 51748    2001-527826         Japan                                         12       10/2/00                 pending
 51748    2002/003420         Mexico                                        12       10/2/00                 pending
</TABLE>

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


                                       79
<PAGE>

                                    EXHIBIT C

                                      FIELD

WHO CLINICAL CLASSIFICATION OF PULMONARY HYPERTENSION (VENICE 2003)

1.   Pulmonary arterial hypertension (PAH)

     1.1. Idiopathic (IPAH)

     1.2. Familial (FPAH)

     1.3. Associated with (APAH):

          1.3.1. Collagen vascular disease

          1.3.2. Congenital systemic-to-pulmonary shunts

          1.3.3. Portal hypertension

          1.3.4. HIV infection

          1.3.5. Drugs and toxins

          1.3.6. Other (thyroid disorders, glycogen storage disease, Gaucher
               disease, hereditary hemorrhagic telangiectasia,
               hemoglobinopathies, myeloproliferative disorders, splenectomy)

     1.4. Associated with significant venous or capillary involvement

          1.4.1. Pulmonary veno-occlusive disease (PVOD)

          1.4.2. Pulmonary capillary hemangiomatosis (PCH)

     1.5. Persistent pulmonary hypertension of the newborn

2.   Pulmonary hypertension with left heart disease

     2.1. Left-sided atrial or ventricular heart disease

     2.2. Left-sided valvular heart disease

3.   PH associated with lung diseases and/or hypoxemia

     3.1. Chronic obstructive pulmonary disease

     3.2. Interstitial lung disease

     3.3. Sleep-disordered breathing

     3.4. Alveolar hypoventilation disorders

     3.5. Chronic exposure to high altitude

     3.6. Developmental abnormalities

4.   Pulmonary hypertension due to chronic thrombotic and/or embolic disease

     4.1. Thromboembolic obstruction of proximal pulmonary arteries

     4.2. Thromboembolic obstruction of distal pulmonary arteries

     4.3. Non-thrombotic pulmonary embolism (tumor, parasites, foreign material)

5.   Miscellaneous

     Sarcoidosis, histiocytosis X, lymphangiomatosis, compression of pulmonary
     vessels (adenopathy, tumor, fibrosing mediastinitis)

<PAGE>

                                    EXHIBIT D

                              MYOGEN PATENT RIGHTS

[..**..]

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


                                        2

<PAGE>

                                    EXHIBIT E

                                MYOGEN TRADEMARKS

<TABLE>
<CAPTION>
                           APPLICATION NO./
        COUNTRY          USPTO REFERENCE NO.   FILING DATE       REGISTRATION NO.
        -------          -------------------   -----------   ------------------------
<S>                      <C>                   <C>           <C>
Australia (Madrid        Application No.       4/8/05
Protocol)                1073936
                         USPTO Reference No.
                         A0001194

Canada                   Application No.       4/12/05
                         1,253,781

CTM (Madrid Protocol)    USPTO Reference No.   4/8/05
                         A0001194

France (Madrid           USPTO Reference No.   4/8/05
Protocol)                A0001194

Germany (Madrid          USPTO Reference No.   4/8/05
Protocol)                A0001194

International            USPTO Reference No.   4/8/05        Registration No. 856,639
Registration             A0001194

Italy (Madrid            USPTO Reference No.   4/8/05
Protocol)                A0001194

Japan (Madrid            USPTO Reference No.   4/8/05
Protocol)                A0001194

Spain (Madrid            USPTO Reference No.   4/8/05
Protocol)                A0001194

U.K. (Madrid Protocol)   USPTO Reference No.   4/8/05
                         A0001194
</TABLE>

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


                                       3

<PAGE>

                                    EXHIBIT F

                  DESIRED EUROPEAN PRODUCT INDICATION STATEMENT

[..**..]

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


                                        4