Exhibit 10.4

SECOND AMENDMENT TO THE EXCLUSIVE LICENSE
AND DISTRIBUTION AGREEMENT

            This SECOND AMENDMENT TO THE EXCLUSIVE LICENSE AND DISTRIBUTION
AGREEMENT (hereinafter, the “Second Amendment”) is entered into and is effective
as of this 29th day of June, 2001 (the “Effective Date”), by and between KING
PHARMACEUTICALS, INC., a Tennessee corporation (hereinafter, “KING”), and
NOVAVAX, INC., a Delaware corporation (hereinafter, “NOVAVAX”).

W I T N E S S E T H:

            WHEREAS, KING and NOVAVAX entered into the Exclusive License and
Distribution Agreement dated as of January 8, 2001 (hereinafter, “the Exclusive
License and Distribution Agreement”), as amended by the First Amendment to the
Exclusive License and Distribution Agreement dated as of the date hereof
(hereinafter, the “First Amendment”);

            WHEREAS, the parties now desire to modify certain provisions of the
Exclusive License and Distribution Agreement, as more specifically set forth
below;

            WHEREAS, KING and NOVAVAX each desire to expand the original
Territory in the Exclusive License and Distribution Agreement to now include
Canada, Italy, the Netherlands, Greece, Switzerland and Spain;

            WHEREAS, King desires to pay NOVAVAX and NOVAVAX desires to receive
from KING additional monies for expanding the original Territory in the
Exclusive License and Distribution Agreement to include Canada, Italy, the
Netherlands, Greece, Switzerland and Spain;

            WHEREAS, KING and NOVAVAX each desire to amend the definition of the
term Territory in ANNEX I, entitled “DEFINITIONS”, attached to the Exclusive
License and Distribution Agreement and as amended in the First Amendment, to
include Canada, Italy, the Netherlands, Greece, Switzerland and Spain;

            WHEREAS, KING and NOVAVAX each desire to amend the definition of the
term Purchase Price in ANNEX I, entitled “DEFINITIONS”, attached to the
Exclusive License and Distribution Agreement and as amended in the First
Amendment; and

            WHEREAS, KING and NOVAVAX each desire to add Canadian Territory,
European Territory, and Original Territory, as newly defined terms to

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ANNEX I, entitled “DEFINITIONS”, attached to the Exclusive License and
Distribution Agreement and as amended in the First Amendment.

            NOW, THEREFORE, in consideration of the mutual covenants and
agreements set forth herein, and intending to be legally bound hereby, the
parties hereto agree as follows:

      1.01      KING and NOVAVAX agree that capitalized terms used herein but
not otherwise defined shall have the same meanings set forth in the Exclusive
License and Distribution Agreement, as amended by the First Amendment.

      1.02      KING and NOVAVAX agree that ANNEX I, entitled “DEFINITIONS”,
attached to the Exclusive License and Distribution Agreement, is hereby amended
by adding Original Territory, Canadian Territory, European Territory, Original
Territory Purchase Price, Canadian Purchase Price, and European Purchase Price
and Regulatory Assets as newly defined terms thereto, as follows:

      “Canadian Purchase Price” shall have the meaning set forth in
Section 5.1(a)(2).

      “Canadian Territory” shall mean Canada, its territories and possessions.

      “European Purchase Price” shall have the meaning set forth in
Section 5.1(a)(3).

      “European Territory” shall mean, collectively, Italy; the Netherlands;
Greece; Switzerland; and Spain, including their territories and possessions.

      “Original Territory” shall mean anywhere in the world except the United
States, its territories and possessions, the District of Columbia, the
Commonwealth of Puerto Rico, the Canadian Territory, and the European Territory.

      “Original Territory Purchase Price” shall have the meaning set forth in
Section 5.1(a)(1).

      “Regulatory Assets” shall mean all registrations, regulatory files,
applications, approvals, licenses, franchises, certificates of compliance and
permits relating to the Products from any governmental authority which regulates
the manufacturing, marketing and/or the sale of drugs or medical products in the
Territory, including, without limitation, any and all NDAs, whether issued,
pending, or in draft form, and all records, reports, data and other information
concerning any of the Products required to be kept under applicable laws in the

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Territory and all correspondence to or from all governmental authorities in the
Territory which relates to the Products.

      1.03       KING and NOVAVAX agree that the terms “Cost of Products”,
“Purchase Price” and “Territory”, and, as set forth in ANNEX I, entitled
DEFINITIONS, attached to the Exclusive License and Distribution Agreement, are
hereby deleted and replaced in their entirety with the following definitions:

      “Cost of Products” shall mean (i) the amount equal to the fully allocated
costs of the Products incurred by NOVAVAX in connection with manufacturing the
Products, and NOVAVAX’s performance of this Agreement, in accordance with GAAP
or (ii) in the event the Products are being manufactured by a third party for
NOVAVAX, then the “Cost of Products” shall mean the invoice amounts actually
paid by NOVAVAX to such third party to purchase the Products.

      “Purchase Price” shall mean either the Original Territory Purchase Price,
Canadian Purchase Price and/or European Purchase Price, as applicable.

      “Territory” shall mean anywhere in the world except the United States, its
territories and possessions, the District of Columbia, and the Commonwealth of
Puerto Rico.

      1.04       KING and NOVAVAX agree that the following Section 2.5 shall be
added to the Exclusive License and Distribution Agreement:

            2.5       Additional Trademark Filings.

            NOVAVAX shall file and register the NOVAVAX Trademarks in such
additional countries in the Territory as KING shall reasonably request, and each
such filing and registration shall be included in the trademarks licensed to
KING under this Agreement.

      1.05       KING and NOVAVAX agree that the following sentence shall be
added to the end of Section 4.2 of the Exclusive License and Distribution
Agreement:

            Notwithstanding anything to the contrary contained in this
Agreement, KING shall own all right, title and interest in and to the Regulatory
Assets.

      1.06       KING and NOVAVAX agree that original Section 5, entitled FEES
and EXPENSES, of the Exclusive License and Distribution Agreement is hereby
deleted

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and replaced in its entirety with the following new Section 5, entitled FEES and
EXPENSES:

      5.       FEES and EXPENSES

            5.1       Purchase Price.

                  (a)       KING and NOVAVAX agree that the Purchase Price for
Product shall be as follows:

                        (1)       For those Products sold by KING in the
Original Territory, KING shall purchase from NOVAVAX, and NOVAVAX shall sell to
KING, the Products at the price equal to the Cost of Products plus ten percent
(10%) (the “Original Territory Purchase Price”). NOVAVAX may, from time to time,
upon thirty (30) calendar days written notice to KING, increase the Original
Territory Purchase Price for one or more Products sold by King in the Original
Territory by an amount equal to the increase in NOVAVAX’s costs for labor and
materials used in connection with the manufacture, storage and/or delivery to
KING of such Products; provided, however, that during the twelve (12) month
period following the Effective Date, NOVAVAX shall not increase the Original
Territory Purchase Price for any Product because of any increased labor cost
experienced by NOVAVAX. Notwithstanding anything to the contrary in the above
Section 5.1(a)(1), in no event shall the total percentage increase in the
Original Territory Purchase Price in any calendar year during the Term exceed
the percentage increase in the Pharmaceutical Producer Price Index,
Pharmaceutical Preparations, Ethical (Prescription) series code PCU-2834 #1,
published by the United States Department of Labor, Bureau of Labor Statistics
(the “PPPI”) for such calendar year.

                        (2)       For those Products sold by KING in the
Canadian Territory, KING shall purchase from NOVAVAX, and NOVAVAX shall sell to
KING, the Products at the price equal to the Cost of Products plus twelve
percent (12%) (the “Canadian Purchase Price”). NOVAVAX may, from time to time,
upon thirty (30) calendar days written notice to KING, increase the Canadian
Purchase Price for one or more Products sold by King in the Canadian Territory
by an amount equal to the increase in NOVAVAX’s costs for labor and materials
used in connection with the manufacture, storage and/or delivery to KING of such
Products; provided, however, that during the twelve (12) month period following
the Effective Date of this Second Amendment, NOVAVAX shall not increase the
Canadian Purchase Price for any Product because of any increased labor cost
experienced by NOVAVAX. Notwithstanding anything to the contrary in the above
Section 5.1(a)(2), in no event shall the total percentage increase in the
Canadian Purchase Price in any calendar year during the Term exceed the
percentage increase in the PPPI for such calendar year.

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                        (3)       For those Products sold by KING in the
European Territory, KING shall purchase from NOVAVAX, and NOVAVAX shall sell to
KING, the Products at the price equal to the Cost of Products plus twenty
percent (20%) (the “European Purchase Price”). NOVAVAX may, from time to time,
upon thirty (30) calendar days written notice to KING, increase the European
Purchase Price for one or more Products sold by KING in the European Territory
by an amount equal to the increase in NOVAVAX’s costs for labor and materials
used in connection with the manufacture, storage and/or delivery to KING of such
European Products; provided, however, that during the twelve (12) month period
following the Effective Date of this Second Amendment, NOVAVAX shall not
increase the European Purchase Price for any Product because of any increased
labor cost experienced by NOVAVAX. Notwithstanding anything to the contrary in
the above Section 5.1(a)(3), in no event shall the total percentage increase in
the European Purchase Price in any calendar year during the Term exceed the
percentage increase in the PPPI for such calendar year.

                  (b)       In addition to the Purchase Price, KING shall pay
all actual freight, insurance and government sales, use, excise, property,
import, export or similar taxes or excises imposed on purchases for resale, and
duties and other fees (except tax on income to NOVAVAX) incurred in connection
with the sale and shipment of the Products to KING.

                  (c)       NOVAVAX shall keep adequate and complete records, in
accordance with GAAP, of all Costs of Products. Such records shall include all
information necessary to verify the total amount and computation of the Purchase
Price due hereunder and NOVAVAX’s compliance with the terms and conditions of
this Agreement, and shall be available once per year to inspection by or on
behalf of KING during normal business hours, upon reasonable notice, to verify
such costs and whether an increase in such costs has occurred and to verify
NOVAVAX’s compliance with this Agreement. NOVAVAX shall retain such records for
not fewer than twenty-four (24) months after the close of any calendar year to
which they relate or such period as required by the FDA. NOVAVAX agrees to make
prompt adjustment, if necessary, to compensate for any errors or omissions
disclosed by such inspection. Should such inspection reveal a shortfall of more
than three percent (3%) between the costs actually incurred and the Costs of
Products reported to KING, the cost of such inspection shall be paid by NOVAVAX.

                  (d)       Payments to NOVAVAX for the Purchase Price of
delivered Products shall be made by KING within thirty (30) days after the later
of (i) the date of delivery thereof to the destination specified by KING, or
(ii) the date of invoice from NOVAVAX.

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                5.2       Royalty Payment.

                        (a)       In addition to the amounts paid under
Section 5.1:

                              (1)       With respect to Products sold in the
Original Territory, KING agrees to pay royalties only on the Net Sales of such
Products at a rate of seven and one-half percent (7.5%) of Net Sales of such
Products. Such royalties are payable forty-five (45) days after the end of each
Calendar Quarter in which such Products are sold in the Original Territory
during the Term of this Agreement;

                              (2)       With respect to Products sold in the
Canadian Territory, KING agrees to pay royalties only on the Net Sales of such
Products at a rate of nine percent (9.0%) of Net Sales of such Products. Such
royalties are payable forty-five (45) days after the end of each Calendar
Quarter in which such Products are sold in the Canadian Territory during the
Term of this Agreement; and

                              (3)       With respect to Products sold in the
European Territory, KING agrees to pay royalties only on the Net Sales of such
Products at a rate of eight percent (8.0%) of Net Sales of such Products. Such
royalties are payable forty-five (45) days after the end of each Calendar
Quarter in which such Products are sold in the European Territory during the
Term of this Agreement.

                        (b)       KING shall keep adequate and complete records,
in accordance with GAAP, showing all Net Sales of Products with respect to which
royalties are due under this Agreement. Such records shall include all
information necessary to verify the total amount and computation of royalties
due hereunder and KING’s compliance with the terms and conditions of this
Agreement, and shall be available once per year to inspection by or on behalf of
NOVAVAX during normal business hours, upon reasonable notice, to verify the
amounts thereof or to ascertain such amounts in the event of a failure of KING
to report and to verify KING’s compliance with this Agreement. KING shall retain
such records for not fewer than twenty-four (24) months after the close of any
calendar year to which they relate or such period as required by the FDA. KING
agrees to make prompt adjustment, if necessary, to compensate for any errors or
omissions disclosed by such inspection. Should such inspection reveal a
shortfall of more than three percent (3%) between the royalties reported and
those actually owed by KING, the cost of such inspection shall be paid by KING.

                5.3       Distribution, Warehousing, Billing, Pricing.

                        KING (and/or its Affiliates) shall have the sole
responsibility for the distribution, warehousing, billing and order confirmation
of the Products to be sold in the Territory after receipt at the designated
destination and for the

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collection of receivables resulting from sales of the Products in the Territory.
KING shall have the sole authority to determine the price of the Products in the
Territory during the Term, including resale price increases and decreases and
the timing thereof.

            5.4       Milestones Payments.

                  Subject to the satisfaction of the conditions set forth below,
KING shall pay NOVAVAX a total of Six Million Dollars ($6,000,000) in milestone
payments for acquiring the exclusive right hereunder to promote, market,
distribute and sell Product in the Canadian Territory and the European
Territory, as follows:

                        (a)       KING shall pay NOVAVAX a one time fee in the
amount of Three Million Dollars ($3,000,000) upon execution of this Second
Amendment;

                        (b)       KING shall pay NOVAVAX a one time fee in the
amount of One Million Dollars ($1,000,000) upon receipt of written notice issued
by an appropriate regulatory authority in the Canadian Territory which grants
final approval to market ESTRASORB™ in the Canadian Territory; and

                        (c)       KING shall pay NOVAVAX a one time fee in the
amount of Two Million Dollars ($2,000,000) upon receipt of written notice issued
by an appropriate regulatory authority in any one of the countries in the
European Territory which grants final approval to market ESTRASORB™ in at least
one of the countries in the European Territory. Other than the one time payment
of Two Million Dollars ($2,000,000) described in the previous sentence, no
additional fees or consideration shall be payable to NOVAVAX in connection with
any subsequent notices issued by any authorities in the European Territory.

      1.07       Except as otherwise expressly provided in this Second
Amendment, KING and NOVAVAX agree that all provisions of the Exclusive License
and Distribution Agreement, as amended by the First Amendment, are hereby
ratified and agreed to be in full force and effect, and are incorporated herein
by reference.

      1.08       The Exclusive License and Distribution Agreement, as amended by
the First Amendment and this Second Amendment, and the Confidentiality
Agreements contain the entire agreement among the parties with respect to the
transactions contemplated herein and supersede any prior agreements,
understandings or arrangements between them, whether oral or in writing. This
Second Amendment may not be amended, modified, altered or supplemented except by
means of a written agreement or other instrument executed by both of the parties
hereto. No course of

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conduct or dealing between the parties shall act as a modification or waiver of
any provisions of this Second Amendment.

      1.09       This Second Amendment may be executed in separate counterparts,
none of which need contain the signatures of all parties, each of which shall be
deemed to be an original, and all of which taken together constitute one and the
same instrument. It shall not be necessary in making proof of this Second
Amendment to produce or account for more than the number of counterparts
containing the respective signatures of, or on behalf of, all of the parties
hereto. Original signatures transmitted by facsimile shall be acceptable to
purposes of executing this Second Amendment. If original signatures are
transmitted by facsimile, the parties shall endeavor in good faith to deliver to
each other executed counterpart originals as soon as practicable after the date
of this Second Amendment.

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      IN WITNESS WHEREOF, each of the parties hereto has executed this Second
Amendment, or has caused this Second Amendment to be duly executed and delivered
in its name on its behalf, all as of the Effective Date first above written.

          KING PHARMACEUTICALS, INC. NOVAVAX, INC. By: By:

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Name: Name:

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Title: Title:

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