<PAGE>

                                                                   EXHIBIT 10.53

          CONFIDENTIAL MATERIALS OMITTED AND FILED SEPARATELY WITH THE
         SECURITIES AND EXCHANGE COMMISSION. ASTERISKS DENOTE OMISSIONS.

                                                                  EXECUTION COPY

                               LICENSING AGREEMENT

         This LICENSING AGREEMENT ("Agreement"), effective as of March 31, 2000
(the "Effective Date"), by and among GILEAD SCIENCES, INC., a Delaware
corporation with its principal office located at 333 Lakeside Drive, Foster
City, CA 94404 ("Gilead Sciences"), and its wholly-owned subsidiary, NEXSTAR
PHARMACEUTICALS, INC., a Delaware corporation (collectively with Gilead
Sciences, "Gilead"), and EYETECH PHARMACEUTICALS, INC., a Delaware corporation
with its principal offices located at 300 East 42nd Street, Third Floor, New
York, New York 10017 ("EyeTech"). Unless otherwise defined in this Agreement,
all capitalized terms shall have the meanings given to them in Section 1.1 of
this Agreement.

                                    RECITALS

         1.       WHEREAS, Gilead owns certain patents and patent applications
and related know-how for NX1838, and has made certain filings for regulatory
approvals with respect to NX1838; and

         2.       WHEREAS, Gilead and EyeTech desire to enter into this
Agreement and certain other agreements, including an agreement providing for the
fill-and-finish manufacture of quantities of Product sufficient for the
completion of Phase Ib clinical trials; and

         3.       WHEREAS, subject to the terms and conditions set forth in this
Agreement, Gilead wishes to license to EyeTech and EyeTech wishes to license
from Gilead all of Gilead's rights under patents, patent applications and
know-how related to NX1838, and have access to all regulatory approvals with
respect to NX1838; and

         4.       WHEREAS, subject to the terms and conditions set forth in this
Agreement, Gilead also wishes to sell to EyeTech and EyeTech wishes to purchase
from Gilead its inventory of NX1838.

         NOW, THEREFORE, the Parties hereto, intending to be legally bound,
hereby agree as follows:

                                    SECTION 1
                                   DEFINITIONS

         1.1      Definitions. For purposes of this Agreement, the following
terms shall have the meanings set forth below:

                                       1.
<PAGE>

         "Affiliate" shall mean any Person that, directly or indirectly, through
one or more intermediaries, Owns, is Owned by or is under common Ownership with,
a Party, where "Own" or "Ownership" means (a) direct or indirect possession of
at least fifty percent (50%) of the outstanding voting securities of a
corporation or a comparable ownership in any other type of Person, provided,
however, that if the law of the jurisdiction in which such entity operates does
not allow fifty percent (50%) or greater ownership by a Party, such ownership
interest shall be at least forty percent (40%) or (b) that a Person or group of
Persons otherwise has the unilateral ability to control and direct the
management of the entity, whether by contract or otherwise.

         "Business Day" shall mean any day other than a Saturday, Sunday or
banking holiday in New York City or San Francisco, California.

         "Calendar Quarter" shall mean a calendar quarter (i.e., period of three
(3) consecutive months) ending on March 31, June 30, September 30 or December
31.

         "Calendar Year" shall mean any period of twelve (12) consecutive months
ending on December 31.

         "Competitive Product" shall mean a product competitive with a Product.

         "Compulsory License" means a compulsory license under the Licensed
Patents obtained by a Third Party through the order, decree, or grant of a
governmental authority of competent jurisdiction, authorizing such Third Party
to manufacture, use, sell, offer for sale or import a Competitive Product in one
or more countries within the Territory.

         "Control", "Controls", and "Controlled" shall mean, with respect to a
particular item of information or intellectual property right, that the
applicable Party owns or has a license to such item or right and has the ability
to grant to the other Party access to and a license or sublicense (as
applicable) under such item or rights as provided for in this Agreement without
violating the terms of any agreement or other arrangement with any Third Party.

         "Damages" shall mean any and all costs, losses, claims, liabilities,
fines, penalties, damages and expenses, court costs, and reasonable fees and
disbursements of counsel, consultants and expert witnesses incurred by a Party
hereto (including any interest payments which may be imposed in connection
therewith).

         "Delivery Date" shall mean the date that is ten (10) days after the
Effective Date.

         "Effective Date" shall have the meaning given such term in the first
sentence of this Agreement.

         "EU" shall mean Austria, Belgium, Denmark, Finland, France, Germany,
Greece, Ireland, Italy, Luxembourg, The Netherlands, Portugal, Spain, Sweden and
the United Kingdom, and future members of the European Union (or its successor),
upon their admission for full membership (with commercial rights and privileges
substantially comparable to those of the foregoing countries).

                                       2.
<PAGE>

         "EyeTech Rights" shall mean any invention or inventions, patentable or
not, know-how, information and/or data relating to the Product, including,
without limitation, pre-clinical studies and clinical trial information,
manufacturing processes, formulations, modes of delivery and/or data necessary
for the manufacture, use or sale of the Product, which are Controlled by EyeTech
during the term of this Agreement, and all Patents covering any of the foregoing
which are Controlled by EyeTech during the term of this Agreement.

         "FDA" shall mean the United States Food and Drug Administration, or any
successor thereto.

         "Field" shall mean the prevention and treatment of all human and other
animal diseases and conditions, and expressly excluding in vivo and in vitro
diagnostic applications.

         "First Commercial Sale" shall mean, with respect to any particular
country, the first sale of a Product in such country by EyeTech, or any of its
Affiliates or sublicensees, after Regulatory Approvals in such country have been
granted from the relevant Regulatory Authority in such country for such Product.

         "GAAP" shall mean United States generally accepted accounting
principles, consistently applied.

         "Indemnified Party" shall have the meaning given in Section 7.2 hereof.

         "Indemnifying Party" shall have the meaning given in Section 7.2
hereof.

         "Know-How" shall mean all ideas, materials, inventions (whether
patentable or not), trade secrets, data, instructions, processes, formulas,
expert opinion and information, including, without limitation, the Manufacturing
Information and biological, chemical, pharmacological, toxicological, physical
and analytical, safety, manufacturing and quality control data and information,
in each case within the Field, that, as of the Effective Date are (i) existing,
and (ii) Controlled by Gilead as of the Effective Date, in each case which is
necessary or useful for the development, manufacture, use, sale or
commercialization of the Product in the Field. Excluded from Know-How are any
Patents, the Licensed Patents and the Transferred Assets.

         "License" shall mean the license granted by Gilead to EyeTech pursuant
to Section 2.1.

         "Licensed Patents" shall mean any Patents listed in Exhibit D (as
updated from time to time pursuant to Section 5.6) which claim the manufacture,
use, import, offer for sale or sale of Products in accordance with this
Agreement and which now or at any time during the term of this Agreement are
Controlled by Gilead or any Affiliate of Gilead.

         "Major Countries" shall mean Canada, France, Germany, Italy, Japan,
Spain, United Kingdom and the United States.

         "Manufacturing Information" shall mean copies of all existing
information in written and electronic form in Gilead's possession or control as
of the Effective Date, with respect to any Product existing as of the Effective
Date, that relates to, in the Field: (1) processes for the production of NX1838,
and intermediates in the preparation of a Product; (2) the in-process

                                       3.
<PAGE>

analytical controls for production of each of: (a) NX1838; and (b) a Product;
(3) the process, formulation and development reports generated for the
preparation of a Product; (4) the analytical methods and validation for the
quality control release of each of: (a) NX1838; and (b) a Product; and (5) the
stability protocols, stability indicating methods and stability data for each
of: (a) NX1838; and (b) a Product.

         "NDA" shall mean a New Drug Application filed with the FDA requesting
market approval for a new drug product.

         "Net Sales" shall mean, with respect to the Product, the gross amount
billed or invoiced by EyeTech, its Affiliates or sublicensees, to unrelated
Third Parties for the Products in finished product form, less the following
deductions:

                  (a)      trade, quantity and cash discounts allowed, but
expressly excluding discounts or allowances offered as part of a package of
products that includes a Product sold by EyeTech, its Affiliates or
sublicensees;

                  (b)      refunds, chargebacks and any other allowances which
effectively reduce the net selling price;

                  (c)      actual product returns, credits and allowances;

                  (d)      rebates actually paid or credited to any governmental
agency (or branch thereof) or to any Third Party payor, administrator or
contractee;

                  (e)      discounts mandated by, or granted to meet the
requirements of, applicable state, provincial or federal law, wholesaler,
including required chargebacks and retroactive price reductions;

                  (f)      transportation, freight, postage charges and other
charges such as insurance, relating thereto, in each case included as a specific
line item on an invoice to such Third Parties; and

                  (g)      taxes, excises or other governmental charges upon or
measured by the production, sale, transportation, delivery or use of goods, in
each case included as a specific line item on an invoice to such Third Parties.

Notwithstanding the foregoing, amounts received by EyeTech, or its Affiliates or
sublicensees, for the sale of Products among EyeTech and its Affiliates or
sublicensees for resale shall not be included in the computation of Net Sales
hereunder. Net Sales shall be determined from books and records maintained in
accordance with GAAP. In the event the Product is sold as part of a combination
product, or as part of bundled products or as part of a delivery system, the Net
Sales from the combination product, bundled product or delivery system, for the
purposes of determining royalty payments, shall be determined by multiplying the
Net Sales (as defined without regard to this paragraph) of the combination
product by the fraction, A/(A+B) where A is the average sale price of the
Product when sold separately in finished form and B is the average sale price of
the other product(s) or system sold separately in finished form, or, only if the
value of B cannot be determined, where A+B is the average sales price of the
product(s) and

                                       4.
<PAGE>

the delivery system together. If the value of B can be determined, in no event
will the sales price of any combination product, bundled product or delivery
system product be less than the sum of A and B. In the event that such average
sale price cannot be determined for both the Product and such other product(s)
or system in combination, the following calculation shall be substituted for the
calculation recited in (ii) of the preceding sentence: the Net Sales (as defined
without regard to this paragraph) of the combination products shall be
multiplied by the fraction C/(C+D) where C is EyeTech's cost of goods of the
Product and D is EyeTech's cost of goods for the other product(s) or system,
determined in accordance with the method of accounting normally employed by
EyeTech in computing cost of goods, provided, however, that the minimum value of
such fraction as used in the calculation of Net Sales shall be 0.9.

         "NX1838" shall mean Gilead's proprietary compound known as NX1838, as
described in Exhibit A.

         "Party" shall mean either Gilead or EyeTech, and "Parties" shall mean
both of Gilead and EyeTech.

         "Patents" shall mean patents and patent applications, both foreign and
domestic, including without limitation, all extensions, reissues, renewals,
reexaminations, patents of addition, supplementary protection certificates and
inventors' certificates thereof, substitutions, provisionals, divisionals,
continuations and continuations-in-part.

         "Person" shall mean a natural person, a corporation, a partnership, a
trust, a joint venture, a limited liability company, any governmental authority
or any other entity or organization.

         "Pivotal Clinical Trial" shall mean either (a) a trial on sufficient
numbers of patients that is designed to establish that a pharmaceutical product
is safe and efficacious for its intended use, and to define warnings,
precautions and adverse reactions that are associated with the pharmaceutical
product in the dosage range to be prescribed, and to support Regulatory Approval
of such pharmaceutical product or label expansion of such pharmaceutical
product, or (b) a clinical trial that began as a trial on sufficient numbers of
patients that is designed to establish the safety and biological activity of a
pharmaceutical product for its intended use, and to define warnings, precautions
and adverse reactions that are associated with the pharmaceutical product in the
dosage range to be prescribed, after such date as the U.S. Food and Drug
Administration or its successor (or equivalent regulatory authority) has
indicated that the applicable Party may reasonably continue such trials with the
intention to establish that a pharmaceutical product is safe and efficacious for
its intended use, and to define warnings, precautions and adverse reactions that
are associated with the pharmaceutical product in the dosage range to be
prescribed, and to support Regulatory Approval of such pharmaceutical product or
label expansion of such pharmaceutical product.

         "Product" shall mean any pharmaceutical composition containing NX1838
in any formulation, dosage concentration or volume, together with all label
expansions, line extensions and improvements thereon, which may be included in
any supplement, modification or addition to the filings for Regulatory Approval
of the foregoing compound.

                                       5.
<PAGE>

         "Product Data Package" shall include the following information and data
related to the Product in the possession or control of Gilead as of the
Effective Date: (a) the Regulatory Documents; (b) pre-clinical and clinical
development protocols, data, and reports; (c) manufacturing development
technical reports; (d) toxicology reports; and (e) such other information and
data specifically identified in Exhibit B attached hereto.

         "Product Inventory" shall mean the NX1838 and Product inventory, in
bulk or finished form, which Gilead Controls as of the Effective Date, as
identified in Exhibit C attached hereto.

         "Reasonable Diligence" shall mean commercially reasonable efforts to
develop, obtain Regulatory Approval, and/or commercialize, as applicable, a
Product in a country in the Territory, consistent with accepted business
practices and legal requirements, and comparable to efforts in the
pharmaceutical industry applicable to development, obtaining of Regulatory
Approval for, or commercialization of human pharmaceutical products at an
equivalent stage of development and similar market potential, profit potential
and strategic value in view of conditions then prevailing.

         "Regulatory Approval" shall mean (a) in the United States, approval by
the FDA of an NDA, or equivalent application, for marketing approval and
satisfaction of any related applicable FDA registration and notification
requirements (if any) and (b) in any country other than the United States, all
approvals (including any required marketing, pricing and reimbursement
approvals) by the Regulatory Authority in such country of a single application
or set of applications comparable to an NDA, enabling legal sale of a product in
such country.

         "Regulatory Authority" shall mean the FDA in the United States or the
equivalent governmental agency having jurisdiction in any other country in the
Territory.

         "Regulatory Documents" shall mean the (a) United States investigational
new drug application (the "IND") #56503 (dated July 12, 1998), and all
amendments and annual reports to same; (b) any pediatric data package or other
exclusivity extensions relating to Products; and (c) any other regulatory
filings with Regulatory Authorities relating to the Product.


         "Royalty Term" shall mean, with respect to each country in which
Product is sold, the period of time equal to the longer of (i) ten (10) years
from the date of First Commercial Sale of the Product in such country, or (ii)
the expiration of the last-to-expire Licensed Patent in such country that claims
the manufacture, use, and or sale of such Product as such activities are carried
out pursuant to this Agreement.


         "Territory" shall mean the world, unless the License terminates with
respect to a country pursuant to Section 6.7, in which case the Territory shall
exclude any country in which the License has so terminated.

         "Third Party" shall mean a Person other than EyeTech, Gilead or their
Affiliates.

         "Transferred Assets" shall mean the Product Inventory and the Product
Data Package.

                                       6.
<PAGE>

                                    SECTION 2
           GRANT OF LICENSES AND TRANSFER AND DELIVERY OF TRANSFERRED
                      ASSETS AND MANUFACTURING INFORMATION

         2.1      Grant of License. Subject to the terms and conditions of this
Agreement, during the term of this Agreement, Gilead hereby grants to EyeTech an
exclusive license under the Licensed Patents and Know How to make, have made,
use, sell, offer to sell, import and export the Product within the Field
throughout the Territory, with a right to sublicense to its Affiliates or
(subject to Section 2.4) to any other Person.

         2.2      Transferred Assets. As of the Effective Date, Gilead hereby
assigns, transfers and conveys to EyeTech all of Gilead's right, title and
interest in and to the Transferred Assets (subject to Section 4.5(c)), and
EyeTech hereby accepts such assignment, transfer and conveyance. On or before
the Delivery Date, Gilead shall have delivered to EyeTech all of the Transferred
Assets and the Manufacturing Information. EyeTech shall have up to ten (10) days
after such delivery to inventory the delivered Transferred Assets and
Manufacturing Information and to give notice to Gilead of any Transferred Assets
and Manufacturing Information that were not so delivered. If Gilead receives
notice or otherwise learns after the Delivery Date that it has failed to deliver
any Transferred Assets or Manufacturing Information to EyeTech, Gilead shall
provide to EyeTech any such Transferred Assets or Manufacturing Information no
later than five (5) Business Days after receipt of such notice or knowledge (or
within such longer time as is mutually agreed by EyeTech and Gilead). The
clinical data portion of the Product Data Package shall be provided to EyeTech
in computer-readable format, where available, and otherwise in printed format.
Gilead shall be under no obligation to convert to electronic format any portion
of the Product Data Package that currently is available only in printed format.
In the event that EyeTech is unwilling or unable to assume physical possession
of the Transferred Assets and Manufacturing Information by the Effective Date,
Gilead shall be entitled to charge EyeTech a reasonable fee for storage of the
Transferred Assets and Manufacturing Information beyond the Effective Date.
Gilead shall ship the Transferred Assets to EyeTech F.O.B. to EyeTech's
designated facilities. For a period of 90 days following the receipt by EyeTech
of the Transferred Assets and Manufacturing Information, Gilead personnel shall
be reasonably available during Gilead's normal business hours to respond to
technical inquiries of EyeTech regarding Products as is reasonably requested by
EyeTech. EyeTech acknowledges that Gilead makes no representations or warranties
with respect to the Transferred Assets or Manufacturing Information (other than
as expressly set forth in Section 5 below) and that it accepts such Transferred
Assets and Manufacturing Information "as is."

         2.3      Negative Covenant of EyeTech. EyeTech shall not use or
practice Licensed Patents or Know-How outside the Field or outside the Territory
or for any other purpose except activities that it conducts in compliance with
this Agreement.

         2.4      Sublicenses. EyeTech shall have the right to sublicense the
licenses granted to it by Gilead under this Agreement without the consent of
Gilead; provided that (i) prompt notice and a copy of such sublicense shall be
given by EyeTech to Gilead pursuant to Section 8.2 of this Agreement; (ii)
EyeTech shall remain obligated at all times under this Agreement without regard
to whether it has sublicensed its rights or whether EyeTech's sublicensee has
performed; (iii)

                                       7.
<PAGE>

such sublicense shall name Gilead as a third party beneficiary of such
sublicense; and (iv) any such sublicenses granted by EyeTech shall contain
provisions providing for its termination or assignment to Gilead, at the option
of Gilead, of EyeTech's interest therein upon termination of this Agreement, and
shall further contain provisions which obligate such sublicensee to comply with
such terms, conditions, agreements and obligations that are consistent with the
terms, conditions, agreements and obligations to which EyeTech is subject under
this Agreement.

         2.5      Gilead Right of First Negotiation. Except as otherwise
provided in this Section 2.5, Gilead shall have a right of first negotiation
with respect obtaining all rights with respect to any Product which is, or which
can reasonably be expected to be, [**] (a "Reversion Product") as follows:
Eyetech shall notify Gilead in writing if Eyetech intends to seek, negotiate, or
solicit offers to license a Third Party to commercialize the Reversion Product
for the treatment or prevention [**] (the "Reversion Field") and a specific
territory (the "Reversion Territory"), prior to contacting any such potential
Third Party licensees. Such written notice shall include sufficient detailed
technical information concerning the Reversion Product as Gilead may reasonably
require to evaluate its interest in such Reversion Product. Within thirty (30)
days after receiving Eyetech's notice as to the Reversion Product, Gilead shall
notify Eyetech whether it is interested in negotiating with Eyetech the terms
under which Gilead shall obtain a license from Eyetech to research, develop and
commercialize Reversion Products as described herein. If Gilead provides such
notice, the Parties shall negotiate exclusively and in good faith for a period
of up to ninety (90) days after Eyetech receives Gilead's notice of interest
(the "Negotiation Period") the terms of an agreement pursuant to which Eyetech
will grant to Gilead and its Affiliates an exclusive, royalty-bearing,
sublicensable license, under all Eyetech Know-How and Eyetech Patents relating
to such Reversion Product, to research, develop, make, have made, use, import,
offer for sale, sell and otherwise commercialize such Reversion Product within
the Reversion Field within the Reversion Territory, and which agreement shall
include commercially reasonable provisions for transfer of or access to relevant
regulatory filings and technology to Gilead. Neither Gilead nor Eyetech shall
have any obligation to actually enter into a license agreement with respect to
such Reversion Product. If either Gilead does not respond to Eyetech's notice of
intent to license the Reversion Product within thirty (30) days after Gilead's
receipt thereof, or Gilead and Eyetech fail to agree upon the terms of a license
under rights to the Reversion Product during the Negotiation Period, Eyetech
shall be free to commercialize such Reversion Product by itself or through its
Affiliates or Third Parties without further obligation to Gilead.

                                    SECTION 3
                             PAYMENTS AND DELIVERIES

         In consideration of the exclusive license granted herein and the
transfer of ownership of the Transferred Assets, EyeTech shall pay the following
amounts to Gilead:

         3.1      Initial Payments and Deliveries.


                  (a)      On Monday, April 3, 2000, EyeTech shall pay to Gilead
the sum of seven million United States Dollars (US$7,000,000) by Federal Reserve
electronic wire transfer in immediately available funds to an account designated
by Gilead. Such amount shall be non-refundable and non-creditable, and shall not
be subject to any counterclaim or set-off.


                                       8.
<PAGE>

                  (b)      On or before the Effective Date, EyeTech and Gilead
Sciences shall enter into a Warrant Agreement (the "Warrant Agreement") mutually
satisfactory to both Parties pursuant to which EyeTech shall issue to Gilead
Sciences a warrant to purchase EyeTech Series B Preferred Stock.

                  (c)      On or before the Delivery Date, Gilead shall deliver
to EyeTech (i) all of the Transferred Assets pursuant to Section 2.2 of this
Agreement; (ii) all of the Manufacturing Information pursuant to Section 2.2 of
this Agreement; and (iii) a schedule ("Schedule of Transferred Assets and
Manufacturing Information") setting forth each of the Transferred Assets and
Manufacturing Information being delivered to EyeTech at such time.

                  (d)      Within ten (10) days of delivery of the Transferred
Assets and the Manufacturing Information and of the Schedule of Transferred
Assets and Manufacturing Information pursuant to Section 3.1(c) above, EyeTech
shall inventory the delivered Transferred Assets and Manufacturing Information
pursuant to Section 2.2 and shall either (i) deliver to Gilead a receipt
acknowledging the receipt of each of the Transferred Assets and the
Manufacturing Information set forth on the Schedule of Transferred Assets and
Manufacturing Information or (ii) notify Gilead of any Transferred Assets or
Manufacturing Information that Gilead did not deliver. If Gilead receives notice
or otherwise learns after the Delivery Date that it has failed to deliver any
Transferred Assets or Manufacturing Information to EyeTech, Gilead shall provide
to EyeTech any such Transferred Assets or Manufacturing Information no later
than five (5) Business Days after receipt of such notice or knowledge (or within
such longer time as is mutually agreed by EyeTech and Gilead). Within ten (10)
days of Gilead delivering such missing items to EyeTech following notice given
by EyeTech pursuant to clause (ii) of this Section 3.1(d), EyeTech shall deliver
the receipt described in clause (i) of this Section 3.1(d).

         3.2      Milestone Payments. Within five (5) Business Days of EyeTech
and/or its Affiliates or sublicensees achieving the first occurrence of each of
the milestone events listed below with respect to any Product, EyeTech shall
notify Gilead of such achievement and the date thereof, and within thirty (30)
days of the date of such achievement, pay the one-time non-refundable fees
specified below to Gilead by Federal Reserve electronic wire transfer in
immediately available funds to an account designated by Gilead; provided,
however, that in no event shall the following fees be payable more than once
with respect to Products for any particular geographical area or Milestone:

<TABLE>
<CAPTION>
            Milestone                                                      Fee
------------------------------------                                      -----
<S>                                                                       <C>
First [**] with respect to a Product                                      $[**]

First [**] with respect to a Product                                      $[**]

First [**] with respect to a Product                                      $[**]

First [**] with respect to a Product                                      $[**]

First [**] with respect to a Product                                      $[**]

First [**] with respect to a Product                                      $[**]
</TABLE>

                                       9.
<PAGE>

         3.3      Royalties.

                  (a)      Royalty on Products. EyeTech shall pay Gilead a
royalty payment on Net Sales of Products that are made or sold during the
Royalty Term and that are sold by EyeTech, its Affiliates or sublicensees (the
"Royalty") according to the following rates, as adjusted in accordance with
Sections 3.3(b) below:

                           (i)      [**] percent ([**]%) of Net Sales in the
United States for the first [**] million dollars ($[**]) in Net Sales in the
United States in a given Calendar Year;

                           (ii)     [**] percent ([**]%) of Net Sales in the
United States for the next [**] dollars ($[**]), up to and including, [**]
dollars ($[**]) in Net Sales during the same Calendar Year;

                           (iii)    [**] percent ([**]%) of Net Sales in the
United States in excess of [**] dollars ($[**]) during the same Calendar Year;
and

                           (iv)     [**] percent [**]%) of Net Sales outside the
United States in the same Calendar Year.

         By way of example, if, in the year 2005, EyeTech Net Sales in the
United States were equal to [**] dollars ($[**]), and [**] dollars ($[**])
outside the United States, then the Royalty payable to Gilead hereunder would
equal [**] dollars ($[**]), calculated in the following manner:

<TABLE>
<CAPTION>
AMOUNT OF NET SALES                               ROYALTY RATE           ROYALTY
----------------------------                      ------------           -------
<S>                                               <C>                    <C>
First $[**] (United States)                           [**]%               $ [**]
Next $[**] (United States)                            [**]%               $ [**]
Next $[**] (United States)                            [**]%               $ [**]
$[**] (outside United States)                         [**]%               $ [**]
----------------------------                                              ------
       Total Royalty                                                      $ [**]
</TABLE>

         By way of further example, if, through the second Calendar Quarter in
the year 2005, EyeTech Net Sales in the United States were equal to [**] dollars
($[**]), and [**] dollars ($[**]) outside the United States, then the Royalty
payable to Gilead hereunder after such Calendar Quarter would equal [**] dollars
($[**]), calculated in the following manner:

<TABLE>
<CAPTION>
AMOUNT OF NET SALES                               ROYALTY RATE           ROYALTY
                                                  ------------           -------
<S>                                               <C>                    <C>
First $[**] (United States)                           [**]%               $ [**]
Next $[**] (United States)                            [**]%               $ [**]
$[**] (outside United States)                         [**]%               $ [**]
----------------------------                                              ------
       Total Royalty                                                      $ [**]
</TABLE>

                                      10.
<PAGE>

                  (b)      Offset. Notwithstanding the forgoing, on a country by
country and Product by Product basis, EyeTech may credit against Net Sales [**]
percent ([**]%) of any royalties it must pay to any Third Party on any Product:
(1) pursuant to any licenses necessary to practice the License; or (2) resulting
from any litigation (including settlement thereof) under Section 6.16; provided,
however, for purposes of this Section 3.3(b) that the applicable royalty rates
used for calculation of Royalties payable to Gilead shall not be reduced to less
than [**] percent ([**]%) of the royalty rates(s) otherwise applicable pursuant
to Section 3.3(a).

         3.4      Payment; Report. All Royalties payable to Gilead under this
Agreement shall be paid in U.S. dollars within sixty (60) days of the end of
each Calendar Quarter or as otherwise specifically provided herein by Federal
Reserve electronic wire transfer in immediately available funds to an account
designated by Gilead. At the time of payment of Royalties, EyeTech shall send to
Gilead a statement with respect to the applicable Calendar Quarter, country by
country and Product by Product, for EyeTech, its Affiliates and sublicensees, of
the amount of aggregate worldwide gross sales and Net Sales, the amount of gross
sales during such Calendar Quarter, an itemized calculation of Net Sales showing
deductions provided for in the definition of Net Sales and in Section 3.3(b),
and, on a cumulative basis for the current Calendar Year, the amount of
Royalties or other payments due on such sales.

         3.5      Exchange Rate; Manner and Place of Payment.

                  (a)      All payments due hereunder from time to time shall be
paid in U.S. Dollars. For purposes of computing such payments, the Net Sales of
Product in countries other than the United States shall be converted into U.S.
Dollars as computed using the average monthly rate of exchange at the time for
such currencies as the rate applicable to the transfer of funds arising from
payments as published in the Wall Street Journal (New York edition). The
currency conversion system used by EyeTech shall be subject to audit by Gilead
as described in Section 3.6 and, if not determined to be a system reflecting the
fair market value of the currencies in question, shall be modified as necessary
to effect currency conversion at fair market value.

                  (b)      Notwithstanding the provisions of Section 3.5(a), if
by reason of any restrictive exchange laws or regulations, EyeTech shall be
unable to convert to U.S. Dollars the amount, determined as above, equivalent to
the amount due by EyeTech hereunder, then EyeTech shall so notify Gilead
promptly and provide an explanation of the circumstances. In such event, EyeTech
shall make all such payments or the balance thereof due hereunder and which is
not paid in foreign currency as provided below, in U.S. Dollars as soon as
reasonably possible after and to the extent that such restrictive exchange laws
or regulations are lifted so as to permit EyeTech to pay amounts due under this
Section 3.5 in U.S. Dollars. EyeTech shall promptly notify Gilead if such
restrictions are so lifted. At its option Gilead shall meanwhile have the right
to request the payment (to it or to its nominee), and, upon request, EyeTech
shall pay or cause to be paid amounts due (or such portions thereof as are
specified by Gilead) in the currency of any other country designated by Gilead
and legally available to EyeTech under the then-existing laws of regulations.
Any payments shall be payable to Gilead by wire transfer at such bank in the
United States as Gilead Sciences shall specify from time to time. Not less than
one (1) Business Day prior to such wire transfer, the remitting party shall
telefax the receiving party advising it of the amount and of the payment to be
made.

                                      11.
<PAGE>

         3.6      Audits. EyeTech and its Affiliates and sublicensees shall keep
full and accurate books and records relating to the financial performance of the
Product. During the term of this Agreement plus four (4) years after termination
or expiration of this Agreement, Gilead shall have the right, during regular
business hours and upon reasonable advance notice, to have such books and
records audited by an independent certified accountant so as to verify the
accuracy of the information previously reported to Gilead. Such information
shall be deemed to be Proprietary Information of EyeTech and, as such, subject
to confidentiality obligations pursuant to Section 6.3. The independent
certified account shall keep confidential any Proprietary Information obtained
during such audit and shall report to Gilead only the amounts of Royalties due
and payable. The cost of such audit shall be borne by Gilead; however, in the
event such audit reveals that the Royalties to Gilead constitute an underpayment
of five percent (5%) or more from that revealed by the audit to be actually
owed, the cost of the audit shall be borne by EyeTech. EyeTech shall include in
all sublicenses granted as permitted under Section 2.4 an audit provision
substantially similar to the foregoing requiring the sublicensee to keep full
and accurate books and records relating to the Product and granting Gilead the
right to audit the accuracy of the information reported by the sublicensee in
connection therewith on the same terms as apply to an audit of EyeTech's records
hereunder. The terms of this Section 3.6 shall survive any termination or
expiration or termination of this Agreement for a period of four (4) years.

         3.7      Withholding Taxes. Any and all taxes levied on account of
royalty payments paid or owed from a country in which provision is made in the
law or by regulation for withholding will be deducted from royalty payments paid
Gilead hereunder. EyeTech shall cooperate with Gilead to claim exemption from
such deductions or withholdings under any double taxation or similar agreement
in force from time to time.

         3.8      Sublicensee Obligations. In the event EyeTech sublicenses its
right to sell a Product, such sublicense shall include an obligation for the
sublicensee to account for and report its Net Sales of Products and provide that
Gilead shall have audit rights therefor pursuant to this Section 3 on the same
basis as if such sales were Net Sales of Products by EyeTech, and EyeTech shall
pay royalty payments to Gilead as if the Net Sales of the sublicensee were Net
Sales of EyeTech.

         3.9      Late Payments. Any amounts not paid by EyeTech when due under
this Agreement shall be subject to interest from and including the date payment
is due through and including the date upon which Gilead has collected
immediately available funds in an account designated by Gilead at a rate equal
to the sum of two percent (2%) plus the prime rate of interest quoted in the
Money Rates section of The Wall Street Journal, calculated daily on the basis of
a 360-day year, or similar reputable data source. No special notice by Gilead to
EyeTech of such interest due shall be required.

         3.10     Compulsory License. If either Party learns that a Third Party
has obtained a Compulsory License in any country in the Territory, such Party
shall promptly notify the other Party of such occurrence. If the royalty rate
payable by the grantee of the Compulsory License is less than the royalty rates
applicable in such country set forth in Section 3.3 of this Agreement, then the
applicable royalty rates set forth in Section 3.3 of this Agreement shall be
reduced to the lower royalty rates applicable in such country pursuant to such
Compulsory License for so long

                                      12.
<PAGE>

as sales of a Competitive Product are made by any Third Party pursuant to the
Compulsory License.

                                    SECTION 4
                         TERM OF AGREEMENT; TERMINATION

         4.1      Term. The term of this Agreement shall commence upon the
Effective Date and, unless sooner terminated as provided in this Section 4,
expire on the expiration of all Royalty Terms for all Products.

         4.2      Licenses upon Expiration. In the event that the Agreement
expires as set forth in Section 4.1 above without early termination, the License
shall automatically become, at EyeTech's election made at least 90 days prior to
such expiration, either (i) an exclusive, irrevocable, royalty-bearing license,
subject to the surviving provisions of the Agreement, to use and/or sublicense
the use of Know How to make, have made, use, import, have imported, offer for
sale, sell, and have sold Product(s) in the Field in the Territory as it exists
at the time of such expiration, subject to payment by EyeTech to Gilead of a
royalty equal to [**] percent ([**]%) of Net Sales of Products made pursuant to
the license under this Section 4.2(i) after the expiration of this Agreement, or
(ii) a non-exclusive, irrevocable, royalty-free, paid-up license, subject to the
surviving provisions of this Agreement, to use and/or sublicense the use of Know
How to make, have made, use, import, have imported, offer for sale, sell, and
have sold Product(s) in the Field in the Territory as it exists at the time of
such expiration.

         4.3      Termination for Breach. Each Party shall have the right to
terminate this Agreement and its obligations hereunder for material breach by
the other Party, which breach remains uncured for sixty (60) days after written
notice is provided to the breaching Party, or in the case of an obligation to
pay royalty payments or other amounts owing under this Agreement, which breach
remains uncured for thirty (30) days after written notice to the breaching
Party; provided, however, that non-payment of any royalty amounts or other
payments owing under this Agreement, for which the non-paying Party reasonably
disputes the obligation or amounts not paid, shall not be deemed a breach of an
obligation to pay royalty payments or other amounts owing under this Agreement,
provided that the non-paying Party has paid all such amounts not in reasonable
dispute.

         4.4      Termination in Event of Patent Challenge. Gilead shall have
the right to terminate this Agreement if EyeTech challenges the validity of the
Licensed Patents within any country in the Territory, effective thirty (30) days
after EyeTech's receipt of written notice of such termination by Gilead.

         4.5      Reversion of Product Rights.

                  (a)      Termination of Agreement. In the event that this
Agreement is terminated pursuant to Sections 4.3 or 4.4 above, other than for
Gilead's material breach of this Agreement, the License shall terminate
immediately upon such termination.

                  (b)      Loss of License Rights in Country. In the event that
EyeTech permanently loses its right to use and sell Products in any country
other than by reason of any

                                      13.
<PAGE>

action or failure to act on the part of Gilead or any party acting on behalf of
Gilead, the License shall terminate with respect to such country.

                  (c)      Transfer of Rights. With respect to any and all
countries in which EyeTech's license rights are terminated pursuant to Sections
4.5(a), 4.5(b), or 6.7(b): (i) such country(ies) shall automatically be removed
from the Territory; (ii) EyeTech hereby grants to Gilead an exclusive, freely
sublicensable license under the EyeTech Rights, which license shall be
royalty-free and paid-up, subject to Section 4.5(d), to make, have made, use,
import, offer for sale, sell and otherwise research, develop and commercialize
formulations of the NX1838 in such countries, and Gilead covenants not to
practice such license until the actual termination of EyeTech's license rights
as to such countries pursuant to Sections 4.5(a) or (b); (iii) EyeTech shall
assign all of its right, title and interest in and to, and shall cooperate in
the transfer of all of, the following related to Products to the extent that
EyeTech Controlled such during the term of this Agreement: (A) INDs and
Regulatory Approvals, (B) all pre-clinical and clinical development protocols,
data, and reports and other information and data (with any clinical data to be
in computer-readable format, where available, and otherwise in printed format,
with no obligation of EyeTech to convert to electronic format any portion of
such clinical data that currently is available only in printed format), (C)
manufacturing development technical reports, (D) toxicology reports, and (E)
such other information and data specifically identified in Exhibit B or of such
type (the preceding (A), (B), (C), (D) and (E) constituting the "Updated Product
Data Package"), (iv) EyeTech shall deliver to Gilead copies of all information,
records and data that it Controls that are reasonably necessary for the
research, development and commercialization of Products, including without
limitation all clinical data relating to Products, forward to Gilead samples of
all chemical and biological materials acquired, made, cloned, synthesized, first
discovered or collected as a result of research development or commercialization
of Products and reasonable necessary to continue the research, development and
commercialization of Products, and take such other actions and execute such
other instruments, assignments and documents as may be necessary to effect the
transfer of rights and materials hereunder to Gilead; and (v) EyeTech shall
provide assistance reasonably requested by Gilead for a period of ninety (90)
days following the date of notice of termination to facilitate the exercise of
the license granted to Gilead in Section 4.5(c)(ii).

                  (d)      Royalties. Any license granted to Gilead pursuant to
Section 4.5(c) shall be subject to payment of a royalty to EyeTech on a
country-by-country basis at a rate equal to: (i) if such license is granted
after initiation of Pivotal Clinical Trials for a Product applicable to such
country, [**] percent ([**]%) of Gilead's net sales of Products in such country,
or (ii) if such license is granted on or after the first Regulatory Approval of
Product in such country, [**] percent ([**]%) of Gilead's net sales of Products
in such country.

         4.6      Accrued Rights and Obligations; Survival. Termination or
expiration of this Agreement for any reason shall be without prejudice to any
rights which shall have accrued to the benefit of either Party prior to such
termination or expiration, including damages arising from any breach hereunder.
The following provisions of this Agreement shall survive the expiration or
termination of this Agreement: Sections 2.3, 4.2, 4.6, 5, 6.3, 6.4, 6.5, 6.9,
6.11(a), 6.12, 6.18, 7, 8. The following provisions of this Agreement shall
survive the expiration of this Agreement to the extent that the license granted
to EyeTech pursuant to Section 4.2 is in effect: Sections 3.4 through 3.9, 4.3,
4.5, 6.2, 6.7(d), 6.7(f), 6.8, 6.11(b), 6.11(c), 6.11(d), 6.13, 6.16 and
6.17(a).

                                      14.
<PAGE>

                                    SECTION 5
                         REPRESENTATIONS AND WARRANTIES

         5.1      Corporate Existence and Power. As of the Effective Date, each
Party represents and warrants to the other that it (a) is a corporation duly
organized, validly existing and in good standing under the laws of the state in
which it is incorporated, and (b) has full corporate power and authority and the
legal right to own and operate its property and assets and to carry on its
business as it is now being conducted and as contemplated in this Agreement,
including, without limitation, the right to grant the licenses granted
hereunder.

         5.2      Authority and Binding Agreement. As of the Effective Date,
each Party represents and warrants to the other that it (a) has the corporate
power and authority and the legal right to enter into this Agreement and perform
its obligations hereunder, (b) has taken all necessary corporate action on its
part required to authorize the execution and delivery of the Agreement and the
performance of its obligations hereunder, and (c) the Agreement has been duly
executed and delivered on behalf of such Party, and constitutes a legal, valid
and binding obligation of such Party and is enforceable against it in accordance
with its terms.

         5.3      Title. As of the Effective Date, each Party represents and
warrants to the other that it has sufficient legal and/or beneficial title under
its intellectual property rights necessary to perform activities contemplated
under this Agreement and to grant the licenses contained in this Agreement and
other ownership rights conveyed pursuant to this Agreement

         5.4      No Conflict. Each Party represents and warrants to the other
that it has not entered, and will not enter, into any agreement with any Third
Party which is in conflict with the rights granted to the other Party under this
Agreement, and has not taken and will not take any action that would in any way
prevent it from granting the rights granted to the other Party under this
Agreement, or that would otherwise materially conflict with or adversely affect
the rights granted to the other Party under this Agreement.

         5.5      No Approvals or Consents Required. Each Party represents and
warrants to the other that all necessary consents, approvals and authorizations
of all governmental authorities and other persons or entities required to be
obtained by such Party in order to enter into this Agreement have been obtained.

         5.6      Patents. Gilead represents and warrants to EyeTech that in
Exhibit D, Gilead has in good faith supplied a complete list of all Patents it
Controls as of the Effective Date, that, but for the grant of the License, would
be infringed by the manufacture, use or sale of Products in the Field. If
EyeTech reasonably determines that any Patent Controlled by Gilead or any
Affiliate of Gilead as of the Effective Date should be added to Exhibit D
because EyeTech's manufacture, use or sale of Products would infringe such
Patent, then there shall be no deemed breach of Gilead's representations and
warranties in this Section 5.6 until after the parties negotiate in good faith
regarding the addition of any such Patent to Exhibit D without any additional
financial obligation and are unable to reach agreement on such addition of such
Patent.

         5.7      No Conflict. Each Party represents and warrants to the other
that the execution and delivery of the Agreement by such Party and the
performance of such Party's obligations

                                      15.
<PAGE>

hereunder (a) do not conflict with or violate any requirement of applicable law
or regulation or any provision of articles of incorporation or bylaws of such
Party in any material way, and (b) do not conflict with, violate or breach or
constitute a default or require any consent under, any contractual obligation or
court or administrative order by which such Party is bound.

         5.8      Regulatory Documents. Gilead represents and warrants to
EyeTech that:

                  (a)      Gilead has furnished EyeTech with access to a
complete copy of the United States Regulatory Documents for the Product,
including all material amendments and supplements thereto;

                  (b)      the Regulatory Documents have been accepted by, and
Gilead has received no notice that the Regulatory Documents are not in good
standing with, the relevant Regulatory Authorities;

                  (c)      to its knowledge, Gilead has filed with the relevant
Regulatory Authorities all required notices, supplemental applications and
annual or other reports, including adverse experience reports, with respect to
the Regulatory Documents which are material;

                  (d)      Gilead has received no written notice of any
regulatory action by the relevant Regulatory Authorities which may reasonably be
expected to have a material adverse effect on the ability of a Party to obtain
Regulatory Approval for Products based upon the Regulatory Documents.

         5.9      Manufacturing Information. Gilead represents and warrants
that, it has delivered or shall by the Delivery Date deliver to EyeTech all of
the Transferred Assets and the Manufacturing Information.

         5.10     Product Quality. Gilead hereby represents and warrants that
all Product Inventory that is provided to EyeTech pursuant to the terms of this
Agreement has been manufactured in compliance with all laws, rules and
regulations (including without limitation, all applicable IND applications)
applicable to the conduct of Gilead's Phase I clinical trial for a Product.

         5.11     Implied Warranties. EXCEPT AS EXPRESSLY PROVIDED IN THIS
SECTION 5, GILEAD MAKES NO REPRESENTATION OR WARRANTY AS TO THE PATENTS,
LICENSED PATENTS, KNOW-HOW, THE TRANSFERRED ASSETS, PRODUCTS, ITS INVENTORY OF
PRODUCTS OR NX1838, EXPRESS OR IMPLIED, EITHER IN FACT OR BY OPERATION OF LAW,
BY STATUTE OR OTHERWISE, INCLUDING WITHOUT LIMITATION ANY IMPLIED WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD
PARTY RIGHTS, OR OTHERWISE, AND GILEAD SPECIFICALLY DISCLAIMS ANY AND ALL
IMPLIED OR STATUTORY WARRANTIES. Without limiting the foregoing, EyeTech
acknowledges that it has not and is not relying upon any implied warranty,
including without limitation implied warranties of merchantability, fitness for
a particular purpose, non-infringement of third party rights, or upon any
representation or warranty whatsoever as to the prospects (financial, regulatory
or otherwise), or the validity or likelihood of success, of any Product after
the Effective Date.

                                      16.
<PAGE>

                                    SECTION 6
               ADDITIONAL COVENANTS AND AGREEMENTS OF THE PARTIES

         6.1      Governmental Filings. Gilead and EyeTech each agree to prepare
and file whatever filings, requests or applications are required to be filed
with any governmental authority in connection with this Agreement and to
cooperate with one another as reasonably necessary to accomplish the foregoing.
Without limiting the generality of the foregoing, prior to, or within five (5)
Business Days following, the assignment, transfer and conveyance by Gilead to
EyeTech of the Transferred Assets pursuant to Section 2.2, Gilead shall have
submitted to the relevant Regulatory Authorities the information required of a
former owner of regulatory filings with respect to the Product, and EyeTech
shall submit to the relevant Regulatory Authorities the information required of
a new owner of regulatory filings with respect to the Product.

         6.2      Compliance with Law. EyeTech shall comply with all
supranational, national, federal, state, provincial and other local laws and
regulations applicable to EyeTech's manufacture, use, development, marketing and
sale of the Product. Without limiting the generality of the foregoing sentence,
EyeTech shall not promote the Product in any manner in conflict with any
applicable laws or regulations.

         6.3      Proprietary Information; Exceptions. Each Party will maintain
all Proprietary Information received by it under this Agreement in trust and
confidence and will not disclose any such Proprietary Information to any Third
Party or use any such Proprietary Information for any purposes other than those
necessary or permitted for performance under this Agreement. In particular,
EyeTech shall not use any Know How for the manufacture or sale of any product
other than a Product in the Field. Each Party may use such Proprietary
Information only to the extent required to accomplish the purposes of this
Agreement. Proprietary Information shall not be used for any purpose or in any
manner that would constitute a violation of any laws or regulations, including
without limitation the export control laws of the United States. Proprietary
Information shall not be reproduced in any form except as required to accomplish
the intent of this Agreement. No Proprietary Information shall be disclosed to
any employee, agent, consultant, Affiliate, or sublicensee who does not have a
need for such information. To the extent that disclosure is authorized by this
Agreement, the disclosing Party will obtain prior agreement, from its employees,
directors, agents, consultants, Affiliates, sublicensees or clinical
investigators to whom disclosure is permitted to be made, to obligations to hold
in confidence and not make use of such information for any purpose other than
those permitted by this Agreement, that are at least as restrictive as those of
this Section 6.3. Each Party will use at least the same standard of care as it
uses to protect its own Proprietary Information of a similar nature to ensure
that such employees, agents, consultants and clinical investigators do not
disclose or make any unauthorized use of such Proprietary Information, but no
less than reasonable care. Each Party will notify the other within two (2)
Business Days upon discovery of any unauthorized use or disclosure of the
Proprietary Information.

         Proprietary Information shall not include any information which, as
shown by competent proof:

                  (a)      is now, or hereafter becomes, through no act or
failure to act on the part of the receiving Party, its employees or contractors
in breach hereof, generally known or available;

                                      17.
<PAGE>

                  (b)      is known by the receiving Party at the time of
receiving such information, as evidenced by its contemporaneous written records;

                  (c)      is hereafter furnished to the receiving Party by a
Third Party, as a matter of right and without restriction on disclosure;

                  (d)      is independently developed by the receiving Party
without any breach of this Agreement, as shown by independent, contemporaneous,
written records; or

                  (e)      is the subject of a prior, express, written
permission to disclose provided by the disclosing Party.

         Notwithstanding any other provision of this Section 6.3, (i) the
Parties agree that they shall issue a press release in the form attached hereto
as Exhibit F, and (ii) either Party may disclose such terms to bona fide
potential corporate partners, to the extent required or contemplated by this
Agreement, and to financial underwriters and other Third Parties with a need to
know such information, provided that all such disclosures shall be made only to
such Third Parties under an obligation of confidentiality and appropriately
limited use.

         6.4      Authorized Disclosure. Notwithstanding any other provision of
this Agreement, each Party may disclose Proprietary Information if such
disclosure:

                  (a)      is in response to a valid order of a court or other
governmental body of the United States or a foreign country, or any political
subdivision thereof; provided, however, that the receiving Party shall first
have given notice to the other Party hereto and shall have made a reasonable
effort to obtain a protective order requiring that the Proprietary Information
so disclosed be used only for the purposes for which the order was issued;

                  (b)      is otherwise required by governmental law, rule or
regulation, including without limitation rules or regulations of the U.S.
Securities and Exchange Commission, or by rules of the National Association of
Securities Dealers; or

                  (c)      is otherwise necessary to file or prosecute patent
applications, prosecute or defend litigation or comply with applicable
governmental regulations or otherwise establish rights or enforce obligations
under this Agreement, but only to the extent that any such disclosure is
necessary. Under no circumstances will EyeTech disclose publicly proprietary
features of Gilead manufacturing technology for NX1838; provided, however, that
Gilead shall cooperate with EyeTech to disclose such information to the extent
required to provide EyeTech with reasonable protection from liability by reason
of this prohibition on disclosure.

         6.5      Return of Proprietary Information. In the event that the
License terminates or expires, EyeTech shall promptly return all Proprietary
Information received by it from Gilead.

         6.6      Expenses. Gilead and EyeTech shall each bear their own direct
and indirect expenses incurred in connection with the negotiation and
preparation of this Agreement and, except as set forth in this Agreement, the
performance of the obligations contemplated hereby.

                                      18.
<PAGE>

         6.7      Efforts.

                  (a)      EyeTech shall use Reasonable Diligence to develop,
obtain Regulatory Approval for, and commercialize Product(s) in the Territory
and shall be solely responsible for all related development, regulatory and
commercialization efforts and costs; provided, however, with respect to
countries in the Territory that are not Major Countries (such countries,
"Non-Major Countries"), EyeTech shall have the right to determine, on a country
by country basis using its reasonable discretion not to pursue Regulatory
Approval in such Non-Major Country because commercialization of the Product is
not economically feasible for EyeTech. EyeTech shall provide Gilead with written
notice of all decisions by EyeTech to not pursue development, Regulatory
Approval or commercialization in a country in the Territory for a Product in the
Field for any reason within thirty (30) days of such decision.

                  (b)      In the event EyeTech or its sublicensees fail to
undertake Reasonable Diligence in developing, obtaining Regulatory Approval of,
and/or commercializing Products in one or more Major Countries in the Territory,
such failure shall (i) automatically cause the License to terminate with respect
to such Major Country(ies) and have the consequences set forth in Section 4.5(c)
with respect to any such Major Country(ies); and (ii) shall entitle Gilead to
terminate this Agreement for material breach under Section 4.3 if there have
been such failures of diligence applying to four (4) or more Major Countries,
with the consequences set forth in Section 4.5(c); provided in each case that
EyeTech (or its sublicensee) does not cure such failure within ninety (90) days
of written notice from Gilead specifying its belief that such failure has
occurred and the reasons therefor. Gilead shall not be entitled to exercise the
foregoing termination rights if EyeTech reasonably disputes Gilead's contention
that EyeTech has failed in such Reasonable Diligence until after the Parties
have first completed dispute resolution procedures pursuant to Section 8.9.

                  (c)      EyeTech's Responsibilities. EyeTech shall be
responsible, at its sole expense, for all development of, regulatory activities
relating to, and commercialization of Products in the Territory beginning on the
Effective Date, including performing clinical development of Products within the
Territory using standard pharmaceutical industry practices, and making all
regulatory filings necessary to obtain Regulatory Approvals of Products in the
Territory. Within thirty (30) days of the Effective Date, EyeTech shall provide
to Gilead a formal clinical development plan for Products in the Field in the
Territory (the "Development Plan"), pursuant to which EyeTech will carry out
development of Products under this Agreement, which shall be reasonably
satisfactory to Gilead. The Development Plan shall be subject to amendment by
EyeTech from time to time, with notice and copy of such amended Development Plan
to Gilead; provided, however, (i) Gilead shall have the right to review such
proposed amendment prior to its adoption; (ii) EyeTech shall in good faith
consider any reasonable comments and considerations raised by Gilead within five
(5) Business Days of Gilead's receipt of such proposed amendment; and (iii) such
proposed amendment is consistent with EyeTech's obligations of Reasonable
Diligence pursuant to Sections 6.7(a) and (b).

                  (d)      Regulatory Filings and Matters. EyeTech will file
such regulatory filings as may be necessary to obtain Regulatory Approvals of
Products within the Territory. EyeTech will be responsible for all
communications with all supranational, regional, federal, state, provincial or
other local regulatory agencies, department, bureaus and other governmental

                                      19.
<PAGE>

authorities with jurisdiction over Regulatory Approvals in connection with such
filings. EyeTech will keep Gilead informed of the status of such filings in each
country, and will provide Gilead with at least sixty (60) days advance notice of
the final submission of an application for Regulatory Approval in any country of
the Territory. EyeTech will promptly advise Gilead each time that it obtains
Regulatory Approval of Products in a country of the Territory. EyeTech shall be
responsible for the reporting of adverse events related to the use of Products
marketed by EyeTech, its Affiliates or sublicensees in the Territory.

                  (e)      Reporting; Meetings. Prior to February 1, May 1,
August 1 and November 1 of each Calendar Year, EyeTech will submit to Gilead,
written reports summarizing the status and progress of the clinical development,
marketing and commercialization efforts for each Product in sufficient detail so
as to allow Gilead to monitor EyeTech's compliance with Section 6.7(a). During
March and September of each Calendar Year, senior executive and scientific
personnel of EyeTech will meet with Gilead representatives to report on the
status of development and commercialization of Products and to consult as to
modifications in the development plan referenced in Section 6.7(c).

         6.8      Pricing. EyeTech shall determine, in its sole discretion, the
pricing, discounting policy and other commercial terms relating solely to
Products. EyeTech agrees that EyeTech, its Affiliates and its sublicensees shall
not subject the selling price of Products to abnormal discounts taken against
Products in order to achieve sales of other products.

         6.9      Export Control. This Agreement is made subject to any
restrictions concerning the export of products or technical information from the
United States of America or other countries which may be imposed upon or related
to Gilead or EyeTech from time to time. Each Party agrees that it will not
export, directly or indirectly, any technical information acquired from the
other Party under this Agreement or any products using such technical
information to a location or in a manner that at the time of export requires an
export license or other governmental approval, without first obtaining the
written consent to do so from the appropriate agency or other governmental
entity.

         6.10     Inability to Develop or Commercialize. EyeTech represents that
it has, and covenants that it will maintain adequate resources and expertise to
fulfill its obligations under this Agreement. During the term of this Agreement,
EyeTech shall provide such information that Gilead may request that is
reasonably necessary for Gilead to verify that EyeTech has adequate resources
and expertise to fulfill its obligations under this Section 6.10.

                                      20.
<PAGE>

         6.11     Compliance with Laws; Cooperation; Maintenance of Original
Documents.

                  (a)      Each Party shall carry out its activities pursuant to
this Agreement in compliance with all applicable supranational, national, state,
provincial and local laws, rules, regulations and guidances.

                  (b)      Gilead and EyeTech each agree to use all commercially
reasonable efforts to take, or cause to be taken, all actions and to do, or
cause to be done, all things necessary or proper to make effective the
transactions contemplated by this Agreement, including such actions as may be
reasonably necessary to obtain approvals and consents of governmental Persons
and other Persons (including, without limitation, all applicable drug listing
and notifications to the relevant Regulatory Authority identifying EyeTech as
the licensee of the Product), in each case as reasonably necessary to allow
EyeTech to develop, obtain Regulatory Approvals for, and commercialize Products
as provided in this Agreement; provided that no Party shall be required in
connection with such activities to (1) make any payment (other than as expressly
required pursuant to this Agreement), or (2) assume any other material
obligation not otherwise required to be assumed by this Agreement.

                  (c)      For so long as EyeTech, its Affiliates or
sublicensees is making, using or selling Products, Gilead shall store and
maintain all original Manufacturing Information in a secure location in
accordance with practices customary for Gilead and the pharmaceutical industry
for regulatory documents and in compliance with applicable laws and regulations,
and, upon proper notice from a Regulatory Authority of competent jurisdiction
over Products, shall make such Manufacturing Information reasonably available to
such Regulatory Authority.

                  (d)      EyeTech shall store and maintain all original Updated
Product Data Package in a secure location in accordance with practices customary
for EyeTech and the pharmaceutical industry for regulatory documents and in
compliance with applicable laws and regulations.

         6.12     Cooperation. If either Party shall become engaged in or
participate in any investigation, claim, litigation or other proceeding with any
Third Party, including any proceeding before a Regulatory Authority, relating in
any way to the Product or any of the Licensed Patents the other Party shall
cooperate in all reasonable respects with such Party in connection therewith,
including, without limitation, using its reasonable efforts to make available to
the other Party such Party's employees who may be helpful with respect to such
investigation, claim, litigation or other proceeding, provided that, for
purposes of this provision, reasonable efforts to make available any employee
shall be deemed to mean providing a Party with reasonable access to any such
employee at no cost for a period of time not to exceed 24 hours (e.g., three
8-hour Business Days). Thereafter, any such employee shall be made available for
such time and upon such terms and conditions (including, but not limited to,
compensation) as the Parties may mutually agree.

         6.13     Exclusive Rights. The licenses granted under this Agreement to
EyeTech are exclusive, and no Person, including without limitation Gilead, shall
have any right with respect to such licenses during the term of this Agreement,
except as otherwise permitted under this Agreement. Except as otherwise
permitted by this Agreement, Gilead shall refrain from granting

                                      21.
<PAGE>

any right to any Third Party relating to NX1838, the Licensed Patents or the
Transferred Assets that would, in any manner, violate the terms of or conflict
with the rights granted to EyeTech pursuant to this Agreement.

         6.14     Patent Prosecution and Maintenance.

                  (a)      Prosecution of Patents. Licensed Patents shall be
prosecuted and maintained in the Territory by Gilead using diligent efforts, at
Gilead's expense, except as otherwise provided in this Section 6.14(a). If
Gilead reasonably determines that it has no material or commercially useful
application for a Licensed Patent, then EyeTech shall have the right to have
Gilead prosecute and maintain such Licensed Patents or file for such patent term
extension therefor at EyeTech's sole expense. EyeTech shall bear all reasonable
costs of any inter partes patent proceeding, including without limitation
oppositions, interferences or contested re-examinations, which proceeding shall
be conducted under the control of Gilead.

                  (b)      EyeTech shall assist Gilead in obtaining patent
extensions and supplementary protection certificates, and provide such other
assistance as reasonably requested by Gilead in connection with the prosecution
and maintenance of the Licensed Patents in any part of the Territory at
EyeTech's sole expense.

         6.15     Infringement of Licensed Patents.

                  (a)      Notice. Each Party shall promptly notify the other in
writing of any alleged infringement by Third Parties of any Licensed Patent
within the Territory and provide any information available to that Party
relating to such alleged infringement or misappropriation. EyeTech shall have no
rights with respect to any infringement of Licensed Patents that occurs outside
of the Field and/or outside the Territory except the right to receive notice
pursuant to this Section 6.15(a).

                  (b)      Enforcement of Licensed Patents against Competitive
Products. If any Licensed Patent is infringed by a Third Party in connection
with the manufacture, use, sale, offer for sale or import of a Competitive
Product within the Field and within the Territory ("Competitive Product
Infringement"), EyeTech shall have the primary right, but not the obligation, to
initiate, prosecute and control any action with respect to such infringement in
the Territory, by counsel of its own choice, to secure the cessation of the
infringement or to enter suit against the infringer. Gilead shall have the right
to participate in any such action with respect to the Licensed Patents and to be
represented by counsel of its own choice. If EyeTech fails to bring an action or
proceeding to enforce a Licensed Patent within a period of one hundred twenty
(120) days after having knowledge of infringement of such Licensed Patent, then
Gilead shall have the right to bring and control any such action by counsel of
its own choice, and EyeTech shall have the right to participate in such action
and be represented by counsel of its own choice. If a Party brings any such
action or proceeding under this Section 6.15(b), the other Party agrees to be
joined as a party plaintiff and to give the first Party reasonable assistance
and authority to control, file and prosecute the suit as necessary. The costs
and expenses of the Party bringing suit under this Section 6.15(b) (including
the internal costs and expenses specifically attributable to such suit) shall be
reimbursed first out of any damages or other monetary awards recovered in favor
of the Parties, and any remaining damages shall be treated as Net Sales of

                                      22.
<PAGE>

EyeTech in its Territory if EyeTech controlled the action or allocated between
the parties in accordance with their economic interest in the profitability of
Products if Gilead controlled the action. No settlement or consent judgment or
other voluntary final disposition of a suit under this Section 6.15(b) relating
to a Licensed Patent may be entered into without the consent of Gilead, not to
be unreasonably withheld.

                  (c)      Enforcement of Licensed Patents against
Non-Competitive Products. With respect to any infringement of Licensed Patents
within the Field and within the Territory that is not a Competitive Product
Infringement, Gilead shall have the primary right, but not the obligation, to
initiate, prosecute and control any action with respect to such infringement, by
counsel of its own choice, to secure the cessation of the infringement or to
enter suit against the infringer and shall be the "Lead Party" and EyeTech shall
be the "Secondary Party". The Secondary Party shall have the right to
participate in any such action with respect to its Patents and to be represented
by counsel of its own choice. If the Lead Party fails to bring an action or
proceeding to enforce a Licensed Patent within a period of one hundred twenty
(120) days after having knowledge of infringement of such Licensed Patent, then
the Secondary Party shall have the right to bring and control any such action by
counsel of its own choice, and the Lead Party shall have the right to
participate in such action and be represented by counsel of its own choice. If a
Party brings any such action or proceeding hereunder, the other Party agrees to
be joined as a party plaintiff and to give the first Party reasonable assistance
and authority to control, file and prosecute the suit as necessary. The costs
and expenses of the Party bringing suit under this Section 6.15(c) (including
the internal costs and expenses specifically attributable to such suit) shall be
reimbursed first out of any damages or other monetary awards recovered in favor
of the Parties, and any remaining damages shall be paid to Gilead if Gilead
controlled the action, or paid to each Party in proportion to their expenditures
in such action, if EyeTech controlled the action. No settlement or consent
judgment or other voluntary final disposition of a suit under this Section
6.15(c) relating to a Licensed Patent may be entered into without the consent of
Gilead, not to be unreasonably withheld.

         6.16     Infringement of Third Party's Rights.

                  (a)      If the practice of the Licensed Patents through the
manufacture, use or sale of Products by EyeTech, its Affiliates or sublicensees
results in a claim for patent infringement against EyeTech, its Affiliates or
sublicensees, the Party to this Agreement first having notice of that claim
shall promptly notify the other Party in writing. The notice shall set forth the
facts of the claim in reasonable detail.

                  (b)      If a Third Party asserts that a patent or other right
owned by or licensed to it is infringed by the practice of the Licensed Patents
through the manufacture, use or sale of Products by EyeTech, its Affiliates or
sublicensees pursuant to the License, EyeTech may attempt to resolve the problem
raised by the asserted infringement. The matter shall be deemed resolved if
EyeTech obtains: (a) a license permitting EyeTech to manufacture, use and sell
Products in that country on a royalty-free or royalty-bearing basis; (b) a
statement or representation from the Third Party that: (1) no action will be
taken against EyeTech, its Affiliates or its sublicensees, or (2) that the
patent or other right is not infringed by the manufacture, use or sale of
Products by EyeTech, its Affiliates or its sublicensees; or (c) a final judgment
by a court of competent jurisdiction from which no appeal has or can be taken
that the

                                      23.
<PAGE>

Third Party's patent(s) alleged to be infringed is invalid, or the Third Party's
patent(s) or other right(s) are unenforceable or not infringed by the
manufacture, use or sale of Products by EyeTech, its Affiliates or sublicensees.
EyeTech shall have the primary right to defend any such claim. Gilead shall have
the right, but not the obligation, to participate in any such suit at its sole
option and at its own expense. Each Party shall reasonably cooperate with the
Party conducting the defense of the claim. Neither Party shall enter into any
settlement that affects the other Party's rights or interests without such other
Party's prior written consent, not to be unreasonably withheld. If EyeTech makes
a payment to any Third Party in the course of defending or settling any claim
brought by a Third Party pursuant to this Section 6.16, EyeTech shall be
entitled to offset a percentage of all such amounts against royalties due to
Gilead hereunder as provided in Section 3.3(b).

         6.17     Manufacturing.

                  (a)      EyeTech shall be solely responsible for the
manufacture of Product following the Effective Date, including without
limitation for clinical trials and commercialization.

                  (b)      The Parties shall enter into an agreement dated as of
the Effective Date (the "Manufacturing Agreement") obligating the Parties to
enter into a clinical supply agreement providing for the fill and finish of
sufficient quantities of Product Inventory to complete a Phase Ib trial
investigating the use of NX1838 for the treatment of age-related macular
degeneration.

         6.18     Use of Names, Logos or Symbols. No Party hereto shall use the
name, trademarks, logos, physical likeness, employee names or owner symbol of
the other Party hereto for any purpose, including, without limitation, in
connection with any private or public securities placements, without the prior
written consent of the affected Party, such consent not to be unreasonably
withheld or delayed so long as such use of name is limited to objective
statements of fact, rather than for endorsement purposes. Nothing contained
herein shall be construed as granting either Party any rights or license to use
any of the other Party's trademarks or trade names without separate, express
written permission of the owner of such trademark or trade name.

                                    SECTION 7
                                 INDEMNIFICATION

         7.1      Indemnification.

                  (a)      Gilead shall indemnify, defend and hold EyeTech (and
its directors, officers, employees, consultants, Affiliates and sublicensees)
(each, an "EyeTech Indemnitee") harmless from and against any and all Damages
incurred or suffered by an EyeTech Indemnitee as a result of Third Party claims,
actions or proceedings (collectively, "EyeTech Claims") to the extent such
EyeTech Claims are a consequence of:

                                    (1)      the breach or alleged breach of any
representation or warranty by Gilead hereunder, or

                                      24.
<PAGE>

                                    (2)      the negligence or misconduct of
Gilead in connection with its activities under this Agreement;

except to the extent such EyeTech Claims are a consequence any of the items in
Sections 7.1(b)(1), (2) or (3).

                  (b)      EyeTech shall indemnify, defend and hold Gilead (and
its directors, officers, employees, consultants and Affiliates) (each, a "Gilead
Indemnitee") harmless from and against any and all Damages incurred or suffered
by a Gilead Indemnitee as a result of Third Party claims, actions or proceedings
(collectively, "Gilead Claims") to the extent such Gilead Claims are a
consequence of:

                                    (1)      the breach or alleged breach of any
representation or warranty by EyeTech hereunder;

                                    (2)      the negligence or willful
misconduct of EyeTech in connection with its activities under this Agreement;

                                    (3)      the possession, research,
development, manufacture, use, offer for sale, sale, administration, storage or
transport of NX1838 or Products by EyeTech or its Affiliates or sublicensees;

except to the extent such Gilead Claims are a consequence any of the items in
Sections 7.1(a)(1) or (2).

         7.2      Mechanics. If a Party or its Affiliate has a right to be
indemnified under this Section 7 (the "Indemnified Party"), such Party or
Affiliate (i) shall give prompt notice of such EyeTech Claim or Gilead Claim, as
the case may be (as applicable, a "Claim"), to the other Party (the
"Indemnifying Party") and (ii) subject to Sections 6.15 and 6.16 of this
Agreement, will have the first right to defend any Claims for which it is
entitled to indemnification from the other Party under Section 7.1, with the
cooperation and at the expense of such other Party, provided that it will not
settle any such Claim without the prior written consent of the Indemnifying
Party, which consent shall not be unreasonably withheld. If the Indemnified
Party is defending a Claim, the Indemnifying Party shall have the right to be
present in person or through counsel at substantive legal proceedings. In the
event that the Parties cannot agree as to the application of Section 7.1 to any
Damages or Claim, the Parties may conduct separate defenses of such claim. Each
Party further reserves the right to claim indemnity from the other in accordance
with Section 7.1 upon resolution of the underlying claim.

         7.3      Insurance Coverage. Each Party represents and warrants that it
is covered and will continue to be covered by a comprehensive general liability
insurance program which covers all of each Party's activities and obligations
hereunder in accordance with reasonable pharmaceutical industry standards. Each
Party will provide the other Party with written notice at least fifteen (15)
days prior to any cancellation or material change in such insurance program.
Each Party will maintain such insurance program, or other program with
comparable coverage, beyond the expiration or termination of this Agreement
during the period in which any Product is being commercially distributed or
sold, and for a commercially reasonable period thereafter.

                                      25.
<PAGE>

         7.4      Indemnification Payment Adjustments. The amount of any Damages
for which indemnification is provided under this Section 7 shall be reduced to
take account of any net tax benefit and shall be increased to take account of
any net tax detriment arising from the incurrence or payment of any such Damages
or from the receipt of any such indemnification payment and shall be reduced by
the insurance proceeds received and any other amount recovered, if any, by the
Indemnified Party with respect to any Damages; provided, however, that an
Indemnified Party shall not be subject to an obligation to pursue an insurance
claim relating to any Damages for which indemnification is sought hereunder. If
any Indemnified Party shall have received any payment pursuant to this Section 7
with respect to any Damages and shall subsequently have received insurance
proceeds or other amounts with respect to such Damages, then such Indemnified
Party shall pay to the Indemnifying Party an amount equal to the difference (if
any) between (1) the sum of the amount of those insurance proceeds or other
amounts received and the amount of the payment by such Indemnifying Party
pursuant to this Section 7 with respect to such Damages and (2) the amount
necessary to fully and completely indemnify and hold harmless such Indemnified
Party from and against such Damages; provided, however, in no event will such
Indemnified Party have any obligation pursuant to this sentence to pay to such
Indemnifying Party an amount greater than the amount of the payment by such
Indemnifying Party pursuant to this Section 7 with respect to such Damages.

         7.5      Indemnification Payment. Upon the final determination of
liability and the amount of the indemnification payment under this Section 7,
the appropriate Party shall pay to the other in immediately available funds,
within thirty (30) Business Days after such determination, the amount of any
claim for indemnification made hereunder.

         7.6      Survival. The provisions of this Section 7 shall survive any
termination of this Agreement with respect to actions of the Parties during the
term of the Agreement or the term of any license to EyeTech, whichever occurs
later. Each Indemnified Party's rights under this Section 7 shall not be deemed
to have been waived or otherwise affected by such Indemnified Party's waiver of
the breach of any representation, warranty, agreement or covenant contained in
or made pursuant to this Agreement, unless such waiver expressly and in writing
also waives any or all of the Indemnified Party's right under Section 7.

                                    SECTION 8
                                  MISCELLANEOUS

         8.1      Successors and Assigns. This Agreement shall be binding upon
and shall inure to the benefit of the Parties hereto and their respective
successors and assigns; provided, however, that neither Gilead nor EyeTech may
assign any of its rights, duties or obligations hereunder without the prior
written consent of the other, which consent may be withheld in the other's sole
discretion, except that no prior written consent shall be required in the event
that a Third Party acquires substantially all of the assets or outstanding
shares of, or merges with, EyeTech or Gilead, as the case may be. No assignment
of this Agreement or of any rights hereunder shall relieve the assigning Party
of any of its obligations or liability hereunder. Any attempted assignment not
in compliance with this Section 8.1 shall be of no force or effect.

         8.2      Notices. All notices or other communications required or
permitted to be given hereunder shall be in writing and shall be deemed to have
been duly given if delivered by hand,

                                      26.
<PAGE>

prepaid telex, cable, telegram or facsimile and confirmed in writing, or mailed
first class, postage prepaid, by registered or certified mail, return receipt
requested (mailed notices and notices sent by telex, cable or telegram shall be
deemed to have been given on the date received) as follows:

                               If to Gilead, as follows:

                               Gilead Sciences, Inc.
                               333 Lakeside Drive,
                               Foster City, CA 94404
                               Facsimile: (650) 522-5488
                               Attn: Chief Executive Officer

                               With a copy to:

                               Gilead Sciences, Inc.
                               333 Lakeside Drive,
                               Foster City, CA 94404
                               Facsimile: (650) 522-5537
                               Attn: General Counsel

                               If to EyeTech, as follows:

                               EyeTech Pharmaceuticals, Inc.
                               300 East 42nd Street
                               Third Floor
                               New York, N.Y. 10017
                               Facsimile: (212) 883-8883
                               Attn: Chief Executive Officer

                               With a copy to:

                               Duval & Stachenfeld LLP
                               300 East 42nd Street
                               Third Floor
                               New York, N.Y. 10017
                               Facsimile: (212) 883-8883
                               Attn: Harsha Murthy

or in any case to such other address or addresses as hereafter shall be
furnished as provided in this Section 8.2 by any Party hereto to the other
Party.

         8.3      Waiver; Remedies. Any term or provision of this Agreement may
be waived at any time by the Party entitled to the benefit thereof by a written
instrument executed by such Party. No delay on the part of Gilead or EyeTech in
exercising any right, power or privilege hereunder shall operate as a waiver
thereof, nor shall any waiver on the part of either Gilead or EyeTech of any
right, power or privilege hereunder operate as a waiver of any other right,
power or privilege hereunder nor shall any single or partial exercise of any
right, power or privilege

                                      27.
<PAGE>

hereunder preclude any other or further exercise thereof or the exercise of any
other right, power or privilege hereunder.

         8.4      Survival of Representations. Each of the representations and
warranties made in this Agreement shall survive the expiration or termination of
this Agreement only with respect to activities conducted or events occurring
prior to the expiration or termination of the Agreement.

         8.5      Entire Agreement. This Agreement, together with all exhibits
hereto and the Warrant Agreement and the Manufacturing Agreement, constitute the
entire agreement between the Parties with respect to the subject matter hereof
and supersedes all prior agreements or understandings of the Parties relating
thereto.

         8.6      Amendment. This Agreement may be modified or amended only by
written agreement of the Parties hereto.

         8.7      Counterparts. This Agreement may be executed in any number of
counterparts, each of which shall be deemed an original but all of which
together shall constitute a single instrument.

         8.8      Governing Law. This Agreement shall be governed and construed
in accordance with the laws of the State of California, excluding its choice of
law rules, except for the application of the Federal Arbitration Act pursuant to
Section 8.9(c)(ii).

         8.9      Dispute Resolution.

                  (a)      The Parties recognize that disputes as to certain
matters may from time to time arise during the term of this Agreement which
relate to either party's rights and/or obligations hereunder or thereunder. It
is the objective of the Parties to establish procedures to facilitate the
resolution of disputes arising under this Agreement in an expedient manner by
mutual cooperation and without resort to litigation. To accomplish this
objective, the Parties agree to follow the procedures set forth in this Section
8.9 if and when a dispute arises under this Agreement. In the event of disputes
between the Parties, a Party seeking to resolve such dispute will, by written
notice to the other Party, have such dispute referred to their respective
executive officers designated below or their successors, for attempted
resolution by good faith negotiations within fourteen (14) days after such
notice is received. Said designated officers are as follows:

                  For EyeTech:      Chief Executive Officer
                  For Gilead:       Chief Executive Officer

         In the event the designated executive officers are not able to resolve
such dispute, either party may at any time after the 14 day period invoke the
provisions of Section 8.9(b) hereinafter.

                  (b)      Following settlement efforts pursuant to Section
8.9(a), any dispute, controversy or claim arising out of or relating to the
validity, construction, enforceability or performance of this Agreement,
including disputes relating to alleged breach or to termination of this
Agreement under Section 4, other than disputes which are expressly prohibited
herein from

                                      28.
<PAGE>

being resolved by this mechanism, shall be settled by binding Alternative
Dispute Resolution ("ADR") in the manner described below:

                           (i)      If a party intends to begin an ADR to
resolve a dispute, such party shall provide written notice (the "ADR Request")
to counsel for the other party informing such other party of such intention and
the issues to be resolved. From the date of the ADR Request and until such time
as any matter has been finally settled by ADR, the running of the time periods
contained in Section 4.3 as to which party must cure a breach of this Agreement
shall be suspended as to the subject matter of the dispute.

                           (ii)     Within ten (10) business days after the
receipt of the ADR Request, the other party may, by written notice to the
counsel for the party initiating ADR, add additional issues to be resolved.

                           (iii)    Disputes regarding the scope, validity and
enforceability of Patents shall not be subject to this Section 8.9, except for
Section 8.9(a), and shall be submitted to a court of competent jurisdiction.

                  (c)      The ADR shall be conducted pursuant to Comprehensive
Rules for Commercial, Real Estate and Construction Disputes then in effect,
except that notwithstanding those rules, the following provisions shall apply to
the ADR hereunder:

                           (i)      The arbitration shall be conducted by a
panel of three arbitrators (the "Panel"). The Panel shall be selected from a
pool of retired independent federal judges to be presented to the Parties by
JAMS.

                           (ii)     The time periods set forth in the JAMS rules
shall be followed, unless a party can demonstrate to the Panel that the
complexity of the issues or other reasons warrant the extension of one or more
of the time tables. In such case, the Panel may extend such time tables, but in
no event shall the time tables being extended so that the ADR proceeding extends
more than 18 months from its beginning to the Award. In regard to such time
tables, the Parties (i) acknowledge that the issues that may arise in any
dispute involving this Agreement may involve a number of complex matters and
(ii) confirm their intention that each party will have the opportunity to
conduct complete discovery with respect to all material issues involved in a
dispute within the framework provided above. Within such time frames, each party
shall have the right to conduct discovery in accordance with the Federal Rules
of Civil Procedure. The Panel shall not award punitive damages to either party
and the Parties shall be deemed to have waived any right to such damages. The
Panel shall, in rendering its decision, apply the substantive law of the State
of California, without regard to its conflict of laws provisions, except that
the interpretation of and enforcement of this Section 8.9(c)(ii) shall be
governed by the Federal Arbitration Act. The Panel shall apply the Federal Rules
of Evidence to the hearing. The proceeding shall take place in San Francisco,
San Mateo or Santa Clara Counties, California. The fees of the Panels and JAMS
shall be paid by the losing Party which shall be designated by the Panel. If the
Panel is unable to designate a losing party, it shall so state and the fees
shall be split equally between the Parties.

                                      29.
<PAGE>

                           (iii)    The Panel is empowered to award any remedy
allowed by law, including money damages, multiple damages, prejudgment interest
and attorneys' fee, and to grant final, complete, interim, or interlocutory
relief, including injunctive relief but excluding punitive damages.

                           (iv)     Except as set forth in Section 8.9(c)(ii),
above, each party shall bear its own legal fees. The Panel shall assess its
costs, fees and expenses against the party losing the ADR unless it believes
that neither party is the clear loser, in which case the Panel shall divide such
fees, costs and expenses according to the Panel's sole discretion.

                           (v)      The ADR proceeding shall be confidential and
the Panel shall issue appropriate protective orders to safeguard each party's
Proprietary Information. Except as required by law, no party shall make (or
instruct the Panel to make) any public announcement with respect to the
proceedings or decision of the Panel without prior written consent of each other
party. The existence of any dispute submitted to ADR, and the award, shall be
kept in confidence by the Parties and the Panel, except as required in
connection with the enforcement of such award or as otherwise required by
applicable law.

                  (d)      The Parties agree that judgment on any arbitral award
issued pursuant to this Section 8.9 shall be entered in the United States
District Court for the Northern District of California or, in the event such
court does not have subject matter jurisdiction over the dispute in question,
such judgment shall be entered in the Superior Court of the State of California,
in the County of San Mateo, and each Party agrees to the co-exclusive personal
jurisdiction of such courts for the purpose of entry of such a judgment.

         8.10     Captions. All section titles or captions contained in this
Agreement, in any Exhibit referred to herein and the table of contents, if any,
to this Agreement are for convenience only, shall not be deemed a part of this
Agreement and shall not affect the meaning or interpretation of this Agreement.

         8.11     No Third Party Rights or Obligations. Except as expressly
provided in Section 7, no provision of this Agreement shall be deemed or
construed in any way to result in the creation of any rights or obligation in
any Person not a Party to this Agreement.

         8.12     Severability. If any provision of this Agreement is found or
declared to be invalid or unenforceable by any court or other competent
authority having jurisdiction, such finding or declaration shall not invalidate
any other provision hereof, and this Agreement shall thereafter continue in full
force and effect. In the event any such provision is so declared invalid or
unenforceable, the Parties shall negotiate an alternative provision that closely
approximates the Parties' intent, to the extent allowable under law.

         8.13     Attachments. All Exhibits and other attachments to this
Agreement are by this reference incorporated herein and made a part of this
Agreement.

         8.14     Disclaimer of Agency. This Agreement shall not constitute any
Party the legal representative or agent of another, nor shall any Party have the
right or authority to assume, create, or incur any Third Party liability or
obligation of any kind, express or implied, against or in the name of or on
behalf of another except as expressly set forth in this Agreement.

                                      30.
<PAGE>

         8.15     Interpretation. This Agreement has been jointly prepared by
the Parties and their respective legal counsel and shall not be strictly
construed against either Party.

         8.16     Force Majeure. Each of the Parties hereto shall be excused
from the performance of its obligations hereunder (except the payment of money)
in the event such performance is prevented by force majeure, provided that the
non-performing Party promptly provides notice of the prevention to the other
Party. Such excuse shall be continued so long as the condition constituting
force majeure continues and the non-performing Party makes and continues to make
reasonable efforts to remove or overcome the condition. For the purposes of this
Agreement, force majeure shall mean any act of God, fire, casualty, flood, war,
earthquake, strike, failure of public utilities, any act, exercise, assertion or
requirement of governmental authority, accident, epidemic, destruction of
facilities, or such other similar occurrences beyond the control of the Party
whose performance is affected.

         8.17     Limitation of Liability. IN NO EVENT SHALL EITHER PARTY OR ITS
RESPECTIVE AFFILIATES AND PERMITTED SUBLICENSEES BE LIABLE FOR SPECIAL,
EXEMPLARY, CONSEQUENTIAL OR PUNITIVE DAMAGES, WHETHER IN CONTRACT, WARRANTY,
TORT, STRICT LIABILITY OR OTHERWISE, EXCEPT TO THE EXTENT SUCH PARTY MAY BE
REQUIRED TO INDEMNIFY THE OTHER PARTY FROM SUCH DAMAGES CLAIMED BY THIRD PARTIES
UNDER SECTION 7.

         8.18     No Assumption of Obligations. Except as expressly provided in
this Agreement: (i) neither Party is assuming any of the other Party's
responsibilities, duties (including, without limitation, compliance with all
applicable laws and regulations), obligations (including payment obligations),
claims, Damages, liabilities, burdens and problems of any nature whatsoever
(collectively, "Obligations"), whether by operation of law or otherwise, and
(ii) without limiting the foregoing, EyeTech is not assuming any of Gilead's
Obligations with respect to Transferred Assets.

                                      31.
<PAGE>

         IN WITNESS WHEREOF, the Parties have caused this Agreement to be duly
executed and delivered as of the day and year first above written.

GILEAD SCIENCES, INC.                        EYETECH PHARMACEUTICALS, INC.

By: /s/Mark L. Perry                         By: /s/David Guyer
    ---------------------------------            -------------------------------
    Mark L. Perry                                David Guyer
    Senior Vice President, Operations            Chief Executive Officer

NEXSTAR PHARMACEUTICALS, INC.

By: /s/Mark L. Perry
    ---------------------------------
    Mark L. Perry
    Chief Financial Officer

                                      32.
<PAGE>

                                    EXHIBIT A

                                     NX1838

         The compound NX1838, is [**]

                                      A-1.
<PAGE>

                                    EXHIBIT B

                    PRODUCT DATA PACKAGE INFORMATION AND DATA

           Regulatory
               IND
               Pre-IND submissions
               IND correspondence
               IND supplements

           Clinical
               Case Report Forms by site
               1838 Project Files
               Investigator Files by Site

           Manufacturing (API)
               Synthesis Batch Records
               Accompanying Analytical Data
               Records of Failed Lots

           Manufacturing (DP)
               Master Production Records
               Bills of Materials
               Assay methods
               Finished Product Specifications

                                      B-1.
<PAGE>

                                    EXHIBIT C

                                PRODUCT INVENTORY

NX1838 PHYSICAL COUNT SHEET

                                              DATE: 03/23/00
                                               COUNTED BY: Felicia Yu, Judy Liou

<TABLE>
<CAPTION>
                                                                     Expiration Date     Physical Count
                                                                     ---------------     --------------
<S>                                                                  <C>                 <C>
NX1838 Lots
     LOT# 131901E  3MGS IN 100 MICROLITERS                               2/29/00                 16
     LOT# 141901E  4MGS IN 100 MICROLITERS                              04/13/99                 50
     LOT# 251901E  3MGS IN 200 MICROLITERS                               7/14/99                149

Ingredients
     1106510911    NX 1838 APTAMER           LOT# 97000690              10/14/99              792.8
     1106510911    NX 1838 APTAMER           LOT# 98000122              10/28/99               5441
     1100500911    SODIUM PHOSP MONOBASIC    LOT# 97000299                7/3/02            11527.1
     1100600911    SODIUM PHOSP DIBASIC      LOT# 97000649              12/18/02              11435
     1200110911    SODIUMCHLORIDI            0.9% INJECTION              5/31/00                 20
     1645080911    SYRINGES                  1 ML W/NEEDLE                 03/01               1100

Other clinical batches
     101804E       1/2 MG DOSE EXPIRE 10/99                                10/99                 12
     111803E       1 MG DOSE EXPIRE 10/99                                  10/99                 12
     201901E       1.5 MG PER SYRINGES EXPIRE 07/00                         7/00                 21
     211901E       2.5 MG PER SYRINGES EXPIRE 06/00                         6/00                 25
     151805E       91599400000 EXPIRE 03/99                                 3/99                  3
     121802E       91299400000 EXPIRE 05/99                                 5/99                  2
</TABLE>

                                      C-1.
<PAGE>

                                    EXHIBIT D

                                LICENSED PATENTS

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


                                      D-1.
<PAGE>
                   "[AMENDMENT NO. 1]" TO LICENSING AGREEMENT

     THIS AMENDMENT NO. 1 (the "Amendment") is entered into as of the 9th day
of May, 2000, by and among GILEAD SCIENCES, INC., a Delaware corporation,
NEXSTAR PHARMACEUTICALS, INC., a Delaware corporation (these two parties
collectively referred to herein as "Gilead") and EYETECH PHARMACEUTICALS, INC.,
a Delaware corporation (hereinafter "EyeTech"), to amend the Licensing
Agreement made effective as of March 31, 2000 (the "Agreement") by and among
Gilead and EyeTech, whereby Gilead licensed EyeTech to further clinically
develop and commercialize Gilead's proprietary compound NX 1838. Capitalized
terms used and not otherwise defined herein shall have the meanings given them
in the Agreement.

                                    RECITALS

     WHEREAS, the Parties desire to amend the Agreement to define the term
"Proprietary Information" which was employed but not defined in the Licensing
Agreement, and to set the term of survival for the confidentiality,
nondisclosure and nonuse obligations pertaining to such Proprietary Information.

     NOW, THEREFORE, in consideration of the foregoing and the covenants and
promises contained in this Amendment, and the Parties hereby amend the
Agreement as follows:

1. Section 1.1 is hereby amended to insert the following defined term and
definition immediately following the definition for Product Inventory:

          "Proprietary Information" shall mean, subject to Section 6.3 of the
     Agreement, any Know-How, patent applications or other confidential
     information of a Party disclosed by such Party to another Party in the
     course of negotiating or performing under this Agreement or any other
     written agreement between the Parties entered into on or prior to May 9,
     2000. Proprietary Information shall be deemed to include the terms of this
     Agreement and the terms of any other written agreement between the Parties
     entered into on or prior to May 9, 2000.

2. Section 6.3 is hereby amended to add the following new paragraph to the end
of such section:

          The obligations of confidentiality, nondisclosure and nonuse contained
     in this Section 6.3 shall survive any expiration or termination of this
     Agreement for a period of five (5) years.

3. The Agreement, as amended by this Amendment, shall remain in full force and
effect according to its terms.

4. This Amendment may be executed in any number of counterparts, each of which
shall be deemed an original, and all of which taken together shall constitute
one and the same instrument.

5. This Amendment shall be effective as of the date first written above.

     IN WITNESS WHEREOF, the parties hereto have duly executed this Amendment
effective as of the date first written above.


GILEAD SCIENCES, INC.                  EYETECH PHARMACEUTICALS, INC.

By:  /s/ Mark L. Perry                 By:  /s/ David Guyer
   ---------------------------------      ----------------------------------

Name:  Mark L. Perry                   Name:  David Guyer

Title: Senior Vice President,          Title: Chief Executive Officer
       Operations


NEXSTAR PHARMACEUTICALS, INC.

By:  /s/ Mark L. Perry
   ---------------------------------

Name:  Mark L. Perry

Title: Chief Financial Officer


<PAGE>

                   "[AMENDMENT NO. 2]" TO LICENSING AGREEMENT

     THIS AMENDMENT NO. 2 ("the Second Amendment") is entered into as of
December 4, 2001, by and between EyeTech Pharmaceuticals, Inc. a Delaware
corporation ("EyeTech") and Gilead Sciences, Inc., a Delaware corporation
("Gilead"), to amend that certain Licensing Agreement dated as of March 31,
2000, as amended by Amendment No. 1 to Licensing Agreement dated as of May 9,
2000 (the "Agreement") by and between EyeTech and Gilead (as successor in
interest to NeXstar Pharmaceuticals, Inc.). Capitalized terms used and not
otherwise defined herein shall have the meanings given them in the Agreement.

     WHEREAS, EyeTech desires to obtain access to notebooks of Gilead relating
or potentially relating to the compound NX1838;

     WHEREAS, Gilead is willing to provide such access to EyeTech personnel if
the information in such notebooks is kept confidential by EyeTech and its
personnel under the terms of the Agreement;

     WHEREAS, in support of EyeTech's activities under the Agreement, Gilead
would like to provide to EyeTech, and EyeTech would like to receive from
Gilead, certain of Gilead's inventory of VEGF aptamer and potentially a
reference standard possessed by Gilead, as determine by Gilead ("Materials").

     NOW, THEREFOR, in consideration of the foregoing and the covenants
herein, EyeTech and Gilead hereby agree, and the Agreement is hereby amended,
as follows:

1. All information learned, received, extracted or copied by EyeTech from
notebooks or other documents or records of Gilead, or excerpts thereof, that
Gilead provides or makes available to EyeTech after the date hereof shall be
deemed to be Proprietary Information of Gilead and subject to provisions in the
Agreement pertaining to Proprietary Information of Gilead.

2. Nothing in this Second Amendment shall be construed as creating any
obligation of Gilead to provide or make available to EyeTech any notebooks or
other documents or records of Gilead, or excerpts thereof, beyond any such
obligation of Gilead currently existing under the Agreement.

3. Gilead will deliver the materials to EyeTech within fifteen (15) days after
the date hereof.

4. EyeTech shall not and shall not permit any person or entity to (a) administer
any Materials to humans under any circumstances; or (b) administer any Materials
to animals except in compliance with U.S. National Institutes of Health
guidelines and all other applicable laws, rules, and regulations.

5. Nothing in this Amendment shall be construed to grant either Party any right
or license beyond those set forth in the Agreement.

6. GILEAD PROVIDES THE MATERIALS "AS IS", WITH NO WARRANTY, EXPRESS, IMPLIED OR
STATUTORY, INCLUDING WITHOUT LIMITATION WARRANTIES OF MERCHANTABILITY, TITLE,
NON-INFRINGEMENT, EXCLUSIVITY, OR FITNESS FOR A PARTICULAR PURPOSE.

7. Solely for purposes of Section 7.1(b) of the Agreement, the Materials will
deemed to included within NX1838.

8. The Agreement, as amended by this Second Amendment, shall remain in full
force and effect according to its terms.

9. This Second Amendment may be executed in any number of counterparts, each of
which shall be deemed an original, and all of which taken together shall
constitute one and the same instrument.

10. This Second Amendment shall be effective as of the date first written above.

     IN WITNESS WHEREOF, the parties hereto have duty executed this Second
Amendment effective as of the date first written above.


EYETECH PHARMACEUTICALS, INC.                GILEAD SCIENCES, INC.

By:    /s/  Harsha Murthy                    By:    /s/  Nicole Onetto
       ----------------------                       -------------------------

Name:  Harsha Murthy                         Name:  Nicole Onetto

Title: V.P. - Business Development &         Title: SVP Medical Affairs
       General Counsel

1

<PAGE>

                     AMENDMENT NO. 3 TO LICENSING AGREEMENT

         This Amendment No. 3 to Licensing Agreement (the "Third Amendment")
amends, effective August, 2002, the LICENSING AGREEMENT, itself effective
as of March 30, 2002 and previously amended first as of May 9, 2000 and second
as of December 4, 2001 (as so twice amended, the "Agreement") originally by and
among GILEAD SCIENCES, INC., a Delaware corporation with its principal office
located at 333 Lakeside Drive, Foster City, CA 94404 ("Gilead"), and its
wholly-owned subsidiary, NEXSTAR PHARMACEUTICALS, INC., a Delaware corporation,
on the one hand, and EYETECH PHARMACEUTICALS, INC., a Delaware corporation with
its principal office as of the date hereof located at 500 Seventh Avenue, 18th
Floor, New York, New York 10018 ("EyeTech"), on the other hand, and currently
between Gilead and EyeTech. All capitalized terms used herein and not otherwise
defined shall have the meanings given in the Agreement. All references to
"Sections" and "Articles" are to sections and articles of the Agreement unless
otherwise specified below.

         The Parties hereby amend the Agreement as follows:

     1.  The definition of Net Sales is deleted in its entirety and replaced
with the following:

"`Net Sales' shall mean, with respect to the Product, the gross amount billed or
invoiced by EyeTech, its Affiliates or sublicensees to Third Parties for
Products and Combination Products (defined below), less the following deductions
to the extent included in such billed or invoiced or credited amounts:

               (a)  trade, quantity and cash discounts allowed, but expressly
excluding discounts or allowances offered as part of a package of products that
includes a Product sold by EyeTech, its Affiliates or sublicensees;

               (b)  refunds, chargebacks and any other allowances which
effectively reduce the net selling price;

               (c)  actual product returns, credits and allowances allowed to
customers;

               (d)  rebates actually paid or credited to any governmental agency
(or branch thereof) or to any Third Party payor, administrator or contractee;

               (e)  discounts mandated by, or granted to meet the requirements
of, applicable state, provincial or federal law, wholesaler, including required
chargebacks and retroactive price reductions;

               (f)  transportation, freight, postage charges and other charges
such as insurance, relating thereto, in each case included as a specific line
item on an invoice to such Third Parties; and

               (g)  taxes, excises or other governmental charges upon or
measured by the production, sale, transportation, delivery or use of goods, in
each case included as a specific line item on an invoice to such Third Parties.

                                       2.
<PAGE>

If any such sales to Third Parties are made in transactions that are not at
arm's length between the buyer and the seller, then the gross amount to be
included in the calculation of Net Sales shall be the amount that would have
been invoiced had the transaction been conducted at arm's length. Such amount
that would have been invoiced shall be determined, wherever possible, by
reference to the average selling price of the relevant Product in arm's-length
transactions in the relevant country.

If EyeTech, its Affiliate or sublicensee sells a Product in unfinished form to a
Third Party for resale, then the gross amount to be included in the calculation
of Net Sales arising from such sale shall be the amount invoiced by the Third
Party upon resale, in lieu of the amount invoiced by EyeTech, its Affiliates or
sublicensee when selling the Product in unfinished form. Otherwise, where
EyeTech, its Affiliate or sublicensee sells a Product in finished form to a
Third Party that does not require a sublicense under the Licensed Patents for
further resale (a distributor) (each such Third Party hereinafter a
"Distributor"), the amount to be included in the calculation of Net Sales shall
be the price invoiced from EyeTech or its Affiliate or sublicensee to the Third
Party, not the amount invoiced by the Third Party upon resale.

If, in addition to or in lieu of a transfer price paid for quantities of Product
supplied, any Distributor provides consideration to EyeTech, its Affiliate or
sublicensee in connection with any Product or the Distributor's rights or
relationship with EyeTech, its Affiliate or sublicensee in relation thereto,
then such consideration shall be included in the calculation of Net Sales in the
calendar quarter in which it becomes due to EyeTech or its Affiliate or
sublicensee (as applicable).

Notwithstanding the foregoing, amounts received by EyeTech, or its Affiliates or
sublicensees, for the sale of Products among EyeTech and its Affiliates or
sublicensees for resale shall not be included in the computation of Net Sales
hereunder.

Net Sales shall be determined from books and records maintained in accordance
with GAAP, consistently applied throughout the organization and across all
products of the entity whose sales of Product are giving rise to Net Sales.

If any Product (i) contains or is sold with a therapeutically active ingredient
other than NX1838 (such therapeutically active ingredient an "Other Active"),
regardless of whether they are coformulated or physically packaged together, or
(ii) is sold with a mechanical or pharmacological delivery system for the
delivery of such Product (such system, a "Delivery System), (such a Product
including and together with the Other Active or Delivery System, a "Combination
Product") then Net Sales from the Combination Product shall be determined by
multiplying the Net Sales of the Combination Product (as determined without
reference to the calculations of this paragraph) by the fraction A/(A+B), where
A is the average sale price of a Product of the same formulation and dosage when
not sold as part of a Combination Product, and B is the average sale price of
the Other Active or Delivery System when sold separately, or, only if the value
of B cannot be determined, where A+B is the average sales price of the
Combination Product. If A and B can be determined, in no event will the sales
price of the Combination Product be less than the sum of A and B. If both A and
B, and A+B, cannot be determined, then C/(C+D) shall be substituted for A/(A+B)
in such calculation, where C is EyeTech's cost of goods of the Product and D is
EyeTech's cost of goods for the Other Active or Delivery System, determined in
accordance with the method of accounting normally employed by EyeTech in
computing cost of goods sold (which must be in accordance with GAAP consistently
applied throughout EyeTech), provided, however, that the minimum value of

                                       3.
<PAGE>

such fraction as used in the calculation of Net Sales shall be 0.9. All average
prices, for purposes of this paragraph, shall be determined on a
country-by-country and product-by-product basis.

For clarity and without limiting the generality of the foregoing, the inclusion
of PEG (polyethylene gylcol) in a Product, because PEG is not a therapeutically
active molecule, will not in itself be deemed to result in a Combination Product
for purposes of the foregoing paragraph."

     2.   The phrase "with a right to sublicense to its Affiliates or (subject
          to Section 2.4) to any other Person" in Section 2.1 is deleted and
          replaced with the following: "with a right (subject to Section 2.4) to
          sublicense to its Affiliates or to any other Person."

     3.   In Section 2.5, the phrase "EyeTech Know-How and EyeTech Patents" in
          the nineteenth (19th) line is deleted and replaced with the following:
          "EyeTech Rights."

     4.   The following words are included in the sentence that is the text of
          Section 2.3, at the end of the sentence: "within the scope of the
          license granted EyeTech in Section 2.1."

     5.   Section 3.3(b) is deleted in its entirety and replaced with the
          following:

     "Offset. Notwithstanding the foregoing, on a country-by-country and
     Product-by-Product basis, EyeTech may credit against Royalties otherwise
     due hereunder on Net Sales of such Product in such country [**] percent in
     any calendar quarter ([**]%) of any royalties it must pay to any Third
     Party on sales of such Product in such country in such calendar quarter:
     (1) pursuant to any licenses necessary to practice the License; or (2)
     resulting from any litigation (including settlement thereof) under Section
     6.16; provided, however, for purposes of this Section 3.3(b) that the
     applicable royalty rates used for calculation of Royalties payable to
     Gilead shall not be reduced to less than [**]percent ([**]%) of the royalty
     rate(s) otherwise applicable pursuant to Section 3.3(a)."

     6.   The following is inserted between the first and second sentences of
          Section 3.7: "EyeTech shall promptly remit any amounts so withheld to
          the appropriate governmental authority and provide Gilead with written
          evidence of such payment."

     7.   Section 4.6 is deleted in its entirety and replaced with the
          following:

     "Accrued Rights and Obligations; Survival. Termination or expiration of
     this Agreement for any reason shall be without prejudice to any rights
     which shall have accrued to the benefit of either Party prior to such
     termination or expiration, including damages arising from any breach
     hereunder. The following provisions of this Agreement shall survive any
     expiration or termination of this Agreement: Sections 2.3, 3.6, 4.2, 4.6,
     5, 6.3, 6.4, 6.5, 6.9, 6.11(a), 6.12, 6.18, 7, and 8. In addition, the
     following provisions of this Agreement shall survive the expiration of this
     Agreement to the extent that the license granted to EyeTech pursuant to
     Section 4.2 is in effect: Sections 3.4 through 3.9, 4.3, 4.5, 6.2,
     6.7(c)-(e), 6.8, 6.9, 6.11(b), 6.11(c), 6.11(d), 6.13, 6.16 and 6.17(a)."

     8.   The last sentence of Section 6.13 is deleted in its entirety and
          changed to read as follows: "Except as otherwise permitted by this
          Agreement or required by law, Gilead shall refrain from granting any
          right to any Third Party relating to NX1838, the Licensed Patents or
          the

                                       4.
<PAGE>

          Transferred Assets that would, in any manner, violate the terms of or
          conflict with the rights granted to EyeTech pursuant to this
          Agreement.

     9.   The phrase "distribution," is inserted immediately prior to
          "administration" in the second (2nd) line of Section 7.1(b)(3).

     10.  Section 8.2, "Notices" is changed to show EyeTech's address as
          follows: EyeTech Pharmaceuticals, Inc., 500 Seventh Avenue, 18th
          Floor, New York, New York 10018, Facsimile: 212-997-9251, attn: Chief
          Executive Officer.

     11.  The Agreement, as amended by this Third Amendment, remains in full
          force and effect according to its terms.

     12.  Article 18 shall apply to this Third Amendment as if set forth herein
          in its entirety.

          IN WITNESS WHEREOF, the Parties have caused this Third Amendment to be
duly executed and delivered as of the day and year first above written.

GILEAD SCIENCES, INC.                        EYETECH PHARMACEUTICALS, INC.

By: /s/Gregg Alton                           By: /s/David Guyer
   ---------------------------------------      --------------------------------

Name: Gregg Alton                               David Guyer

Title: Vice President and General Counsel       Chief Executive Officer

NEXSTAR PHARMACEUTICALS, INC.

By: ___________________________________

Name: _________________________________

Title: ________________________________

                                       5.