8-K

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                                    FORM 8-K

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



                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported) September 12, 2003



                          ALEXION PHARMACEUTICALS, INC.
- --------------------------------------------------------------------------------
             (Exact Name of Registrant as Specified in its Charter)



         Delaware                      0-27756                     13-3648318
  ------------------------      -----------------------      -------------------
(State or Other Jurisdiction          (Commission              (IRS Employer
of Incorporation)                     File Number)           Identification No.)


   352 Knotter Drive, Cheshire, CT                                  06410
- ---------------------------------------                           ---------
(Address of Principal Executive Offices)                          (Zip Code)



Registrant's telephone number, including area code:    (203) 272-2596
                                                     -------------------


                                 Not Applicable
- --------------------------------------------------------------------------------
          (Former Name or Former Address, if Changed Since Last Report)




Item 5.  Other Events

         On September 12, 2003, the Company entered into an agreement to sell an
aggregate of 3,600,000 shares of its common stock, $.0001 par value per share,
to a syndicate led by Bear, Stearns & Co. Inc. and issued the press release
filed herewith as Exhibit 99.1. The sale is made under the Company's
shelf-registration statement (Registration No. 333-47594 filed October 6, 2000)
relating to the possible sale from time to time of the Company's securities.
This Form 8-K is filed to incorporate the exhibits hereto into that registration
statement.

Item 7.  Financial Statements, Pro Forma Financial Information and Exhibits.

         (c)  Exhibits.

         1.   Underwriting Agreement, dated September 12, 2003, between Alexion
Pharmaceuticals, Inc. and Bear, Stearns & Co. Inc. as Representative of the
several underwriters named in therein.

         99.1  Press Release dated September 12, 2003.


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                                   SIGNATURES

         Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                            ALEXION PHARMACEUTICALS, INC.

Date: September 12, 2003                    By:  /s/ LEONARD BELL, M.D.
                                                --------------------------------
                                            Name:  Leonard Bell, M.D.
                                            Title: Chief Executive Officer,
                                                   Secretary and Treasurer

                                       3

EX-1

                                                                       Exhibit 1


                        3,600,000 Shares of Common Stock


                          ALEXION PHARMACEUTICALS, INC.

                             UNDERWRITING AGREEMENT

                                                              September 12, 2003

BEAR, STEARNS & CO.  INC.
     As Representative of the
     several Underwriters named in
     Schedule I attached hereto (the "Representative")

c/o Bear, Stearns & Co. Inc.
383 Madison Avenue
New York, New York 10179

Ladies and Gentlemen:

         Alexion Pharmaceuticals, Inc., a corporation organized and existing
under the laws of the state of Delaware (the "Company"), proposes, subject to
the terms and conditions stated herein, to issue and sell to the several
underwriters named in Schedule I attached hereto (the "Underwriters") an
aggregate of 3,600,000 shares (the "Shares") of its common stock, par value
$.0001 per share (the "Common Stock"). The Shares are more fully described in
the Registration Statement and Prospectus referred to below.

         1. Representations and Warranties of the Company. The Company
represents and warrants to, and agrees with, the Underwriters that:

         (a) The Company has filed with the Securities and Exchange Commission
(the "Commission") a registration statement on Form S-3 (No. 333-47594,
including a prospectus, for the registration under the Securities Act of 1933,
as amended (the "Securities Act"), of the Shares and the offering from time to
time in accordance with Rule 415 under the Act, which registration statement, as
so amended (including post-effective amendments, if any), has been declared
effective by the Commission and copies of which have heretofore been delivered
to the Underwriters. The registration statement, as amended at the time it
became effective, including the prospectus, financial statements, schedules,
exhibits and other information (if any) deemed to be part of such registration
statement at the time of effectiveness pursuant to Rule 430A or 434(d) under the
Securities Act, is hereinafter referred to as the "Registration Statement." No
other document with respect to the Registration Statement has heretofore been
filed with the Commission, other than the prospectus supplements filed with the
Commission pursuant to Rule 424(b)(5) on October 30, 2000 and October 31, 2000.
All of the Shares have been registered under the Securities Act pursuant to the
Registration Statement. No stop order suspending the effectiveness of either the
Registration Statement has been issued and


                                       1



no proceeding for that purpose has been initiated or threatened by the
Commission. The Company, if required by the Securities Act and the rules and
regulations of the Commission (the "Rules and Regulations"), proposes to file
with the Commission pursuant to Rule 424(b) under the Securities Act ("Rule
424(b)") a supplement to the form of prospectus included in the Registration
Statement. Such supplemented prospectus, in the form in which it is to be filed
with the Commission pursuant to Rule 424(b), and the prospectus included as part
of the Registration Statement at the time the Registration Statement became
effective, are hereinafter collectively referred to as the "Prospectus," except
that if any revised prospectus or prospectus supplement shall be provided to the
Underwriters by the Company for use in connection with the Offering which
differs from the Prospectus (whether or not such revised prospectus or
prospectus supplement is required to be filed by the Company pursuant to Rule
424(b)), the term "Prospectus" shall also refer to such revised prospectus or
prospectus supplement, as the case may be, from and after the time it is first
provided to the Underwriters for such use. Any reference herein to the
Registration Statement or the Prospectus shall be deemed to refer to and include
the documents incorporated by reference therein pursuant to Item 12 of Form S-3
which were filed under the Exchange Act (as defined below) on or before the
effective date of the Registration Statement or the date of the Prospectus, as
the case may be, and any reference herein to the terms "amend", "amendment" or
"supplement" with respect to the Registration Statement or the Prospectus shall
be deemed to refer to and include (i) the filing of any document under the
Exchange Act after the effective date of the Registration Statement or the date
of the Prospectus, as the case may be, which is incorporated therein by
reference and (ii) any such document so filed. All references in this Agreement
to the Registration Statement and the Prospectus, or any amendments or
supplements to any of the foregoing shall be deemed to include any copy thereof
filed with the Commission pursuant to its Electronic Data Gathering, Analysis
and Retrieval System ("EDGAR").

         (b) At the time of the effectiveness of the Registration Statement or
the effectiveness of any post-effective amendment to the Registration Statement,
when the Prospectus is first filed with the Commission pursuant to Rule 424(b)
or Rule 434 under the Securities Act ("Rule 434"), when any supplement to or
amendment of the Prospectus is filed with the Commission, when any document
filed under the Exchange Act was or is filed and at the Closing Date (as
hereinafter defined), the Registration Statement and the Prospectus and any
amendments thereof and supplements thereto complied or will comply in all
material respects with the applicable provisions of the Securities Act, the
Exchange Act and the Rules and Regulations and did not and will not contain an
untrue statement of a material fact and did not and will not omit to state any
material fact required to be stated therein or necessary in order to make the
statements therein (i) in the case of the Registration Statement, not misleading
and (ii) in the case of the Prospectus in light of the circumstances under which
they were made, not misleading. If Rule 434 is used, the Company will comply
with the requirements of Rule 434 and the Prospectus shall not be "materially
different," as such term is used in Rule 434, from the Prospectus included in
the Registration Statement at the time it became effective. No representation
and warranty is made in this subsection (b), however, with respect to any
information contained in or omitted from the Registration Statement or the
Prospectus or any amendment thereof or supplement thereto in reliance upon and
in conformity with information furnished in writing to the Company by or on
behalf of any Underwriter through the Representative specifically for use
therein. The parties acknowledge and agree that such information provided by or
on behalf of any Underwriter through the Representative consists


                                       2



solely of the material included in paragraphs 2, 9, 10 and 11 under the caption
"Underwriting" in the Prospectus.

         (c) PricewaterhouseCoopers LLP, who have certified the financial
statements and supporting schedules and information of the Company and its
subsidiaries that are included or incorporated by reference in the Registration
Statement, are independent public accountants as required by the Securities Act,
the Securities Exchange Act of 1934, as amended (the "Exchange Act") and the
Rules and Regulations.

         (d) Subsequent to the respective dates as of which information is given
in the Registration Statement and the Prospectus, except as disclosed in the
Registration Statement and the Prospectus, the Company has not declared, paid or
made any dividends or other distributions of any kind on or in respect of its
capital stock and there has been no material adverse change or any development
involving a prospective material adverse change, whether or not arising from
transactions in the ordinary course of business, in or affecting (i) the
business, condition (financial or otherwise), results of operations,
stockholders' equity, properties or prospects of the Company and each subsidiary
of the Company listed on Exhibit A hereto (the "Subsidiaries"), taken as a
whole; (ii) the long-term debt or capital stock of the Company and its
Subsidiaries taken as a whole; or (iii) the Offering or consummation of any of
the other transactions contemplated by this Agreement, the Registration
Statement or the Prospectus (a "Material Adverse Change"). Since the date of the
latest balance sheet presented, or incorporated by reference, in the
Registration Statement and the Prospectus, neither the Company nor any
Subsidiary has incurred or undertaken any liabilities or obligations, whether
direct or indirect, liquidated or contingent, matured or unmatured, or entered
into any transactions, including any acquisition or disposition of any business
or asset, which are material to the Company and the Subsidiaries individually or
taken as a whole, except for liabilities, obligations and transactions which are
disclosed in the Registration Statement and the Prospectus.

         (e) The authorized, issued and outstanding capital stock of the Company
is as set forth in the Registration Statement and Prospectus. All of the issued
and outstanding shares of capital stock of the Company are fully paid and
non-assessable and have been duly and validly authorized and issued, in
compliance with all applicable state, federal and foreign securities laws and
not in violation of or subject to any preemptive or similar right that does or
will entitle any person, upon the issuance or sale of any security, to acquire
from the Company or any Subsidiary any Common Stock or other security of the
Company or any Subsidiary or any security convertible into, or exercisable or
exchangeable for, Common Stock or any other such security (any "Relevant
Security"), except for such rights as may have been fully satisfied or waived
prior to the effectiveness of the Registration Statement.

         (f) The Shares have been duly and validly authorized and, when
delivered in accordance with this Agreement, will be duly and validly issued,
fully paid and non-assessable, will have been issued in compliance with all
applicable state, federal and foreign securities laws and will not have been
issued in violation of or subject to any preemptive or similar right that does
or will entitle any person to acquire any Relevant Security from the Company or
any Subsidiary upon issuance or sale of Shares in the Offering. The Common Stock
and the Shares conform to the descriptions thereof contained in the Registration
Statement and the Prospectus. Except as disclosed in the Registration Statement
and the Prospectus, neither the Company nor


                                       3



any Subsidiary has outstanding warrants, options to purchase, or any preemptive
rights or other rights to subscribe for or to purchase, or any contracts or
commitments to issue or sell, any Relevant Security.

         (g) The Subsidiaries are the only subsidiaries of the Company within
the meaning of Rule 405 under the Securities Act. Except for the Subsidiaries
and as otherwise disclosed in the Registration Statement and the Prospectus, the
Company holds no ownership or other interest, nominal or beneficial, direct or
indirect, in any corporation, partnership, joint venture or other business
entity. Except as disclosed in the Registration Statement and the Prospectus,
all of the issued shares of capital stock of or other ownership interests in
each Subsidiary have been duly and validly authorized and issued and are fully
paid and non-assessable and are owned directly or indirectly by the Company free
and clear of any lien, charge, mortgage, pledge, security interest, claim,
equity, trust or other encumbrance, preferential arrangement, defect or
restriction of any kind whatsoever (any "Lien").

         (h) Each of the Company and the Subsidiaries has been duly organized
and validly exists as a corporation, partnership or limited liability company in
good standing under the laws of its jurisdiction of organization. Each of the
Company and the Subsidiaries has all requisite corporate power and authority to
carry on its business as it is currently being conducted and as described in the
Prospectus, and to own, lease and operate its respective properties. Each of the
Company and the Subsidiaries is duly qualified to do business and is in good
standing as a foreign corporation, partnership or limited liability company in
each jurisdiction in which the character or location of its properties (owned,
leased or licensed) or the nature or conduct of its business makes such
qualification necessary, except for those failures to be so qualified or in good
standing which, individually and in the aggregate, could not reasonably be
expected to have a material adverse effect on (i) the business, condition
(financial or otherwise), results of operations, stockholders' equity,
properties or prospects of the Company and the Subsidiaries, individually or
taken as a whole; (ii) the long-term debt or capital stock of the Company or any
Subsidiary; or (iii) the Offering or consummation of any of the other
transactions contemplated by this Agreement, the Registration Statement or the
Prospectus (any such effect being a "Material Adverse Effect").

         (i) Except as set forth in the Registration Statement and Prospectus,
each of the Company and the Subsidiaries has all necessary consents, approvals,
authorizations, orders, certifications, registrations, easements,
qualifications, licenses, grants, franchises, filings and permits of, with and
from all judicial, regulatory and other legal or governmental agencies and
bodies and all third parties, foreign and domestic (including those of the U.S.
Food and Drug Administration, the U.S. Nuclear Regulatory Commission and any
federal, state or foreign agencies engaged in the regulation of pharmaceuticals
or biohazardous substances) (collectively, the "Consents"), to own, lease and
operate its properties and conduct its business as it is now being conducted as
disclosed in the Registration Statement and the Prospectus, and each such
Consent is valid and in full force and effect, and neither the Company nor any
Subsidiary has received notice of any investigation or proceedings which results
in or, if decided adversely to the Company or any Subsidiary, could reasonably
be expected to result in, the revocation of, or imposition of a materially
burdensome restriction on, any Consent. Each of the Company and the Subsidiaries
is in compliance with all applicable laws, rules, regulations, ordinances,
directives, judgments, decrees and orders, foreign and domestic, except where
failure to be in


                                       4



compliance could not reasonably be expected to have a Material Adverse Effect.
No Consent contains a materially burdensome restriction not adequately disclosed
in the Registration Statement and the Prospectus.

         (j) The Company has full right, power and authority to execute and
deliver this Agreement, to perform its obligations hereunder and to consummate
the transactions contemplated by this Agreement, the Registration Statement and
the Prospectus. This Agreement and the transactions contemplated by this
Agreement, the Registration Statement and the Prospectus have been duly and
validly authorized by the Company. This Agreement has been duly and validly
executed and delivered by the Company and constitutes the legal, valid and
binding obligation of the Company, enforceable in accordance with its terms,
except as enforceability may be limited by applicable bankruptcy, insolvency,
reorganization, moratorium or similar laws affecting creditors' rights generally
and except as enforceability may be subject to general principles of equity
(regardless of whether such enforceability is considered in a proceeding in
equity or at law).

         (k) The execution, delivery, and performance of this Agreement and
consummation of the transactions contemplated by this Agreement, the
Registration Statement and the Prospectus do not and will not (i) conflict with,
require consent under or result in a breach of any of the terms and provisions
of, or constitute a default (or an event which with notice or lapse of time, or
both, would constitute a default) under, or result in the creation or imposition
of any lien, charge or encumbrance upon any property or assets of the Company or
any Subsidiary pursuant to, any indenture, mortgage, deed of trust, loan
agreement or other agreement, instrument, franchise, license or permit to which
the Company or any Subsidiary is a party or by which the Company or any
Subsidiary or their respective properties, operations or assets may be bound or
(ii) violate or conflict with any provision of the certificate or articles of
incorporation, by-laws, certificate of formation, limited liability company
agreement, partnership agreement or other organizational documents of the
Company or any Subsidiary, or (iii) violate or conflict with any law, rule,
regulation, ordinance, directive, judgment, decree or order of any judicial,
regulatory or other legal or governmental agency or body, domestic or foreign,
except (in the case of clauses (i) and (iii) above) as could not reasonably be
expected to have a Material Adverse Effect.

         (l) No Consent of, with or from any judicial, regulatory or other legal
or governmental agency or body or any third party, foreign or domestic, is
required for the execution, delivery and performance of this Agreement or
consummation of the transactions contemplated by this Agreement, the
Registration Statement and the Prospectus, including the issuance, sale and
delivery of the Shares to be issued, sold and delivered hereunder, except the
registration under the Securities Act of the Shares, which has become effective,
and such Consents as may be required under state securities or blue sky laws or
the by-laws and rules of the National Association of Securities Dealers, Inc.
(the "NASD") or NASD Regulation, Inc. ("NASDR") in connection with the purchase
and distribution of the Shares by the Underwriters, each of which has been
obtained and is in full force and effect, other than, as of the date of this
Agreement, the approval of the NASDAQ Notification Form: Listing of Additional
Shares by NASDAQ.


                                       5



         (m) Except as disclosed in the Registration Statement and the
Prospectus, there is no judicial, regulatory, arbitral or other legal or
governmental proceeding or other litigation or arbitration, domestic or foreign,
pending to which the Company or any Subsidiary is a party or of which any
property, operations or assets of the Company or any Subsidiary is the subject
which, individually or in the aggregate, if determined adversely to the Company
or any Subsidiary, could reasonably be expected to have a Material Adverse
Effect; to the best of the Company's knowledge, no such proceeding, litigation
or arbitration is threatened or contemplated; and the defense of all such
proceedings, litigation and arbitration against or involving the Company or any
Subsidiary could not reasonably be expected to have a Material Adverse Effect.

         (n) The financial statements, including the notes thereto, and the
supporting schedules included or incorporated by reference in the Registration
Statement and the Prospectus present fairly the financial position as of the
dates indicated and the cash flows and results of operations for the periods
specified of the Company and its consolidated subsidiaries and the other
entities for which financial statements are included or incorporated by
reference in the Registration Statement and the Prospectus; except as otherwise
stated in the Registration Statement and the Prospectus, said financial
statements have been prepared in conformity with United States generally
accepted accounting principles applied on a consistent basis throughout the
periods involved; and the supporting schedules included or incorporated by
reference in the Registration Statement and the Prospectus present fairly the
information required to be stated therein. No other financial statements or
supporting schedules are required to be included in the Registration Statement.
The other financial and statistical information included or incorporated by
reference in the Registration Statement and the Prospectus present fairly the
information included therein and have been prepared on a basis consistent with
that of the financial statements that are included or incorporated by reference
in the Registration Statement and the Prospectus and the books and records of
the respective entities presented therein.

         (o) There are no pro forma or as adjusted financial statements which
are required to be included or incorporated by reference in the Registration
Statement and the Prospectus in accordance with Regulation S-X which have not
been included as so required.

         (p) The statistical, industry-related and market-related data included
in the Registration Statement and the Prospectus are based on or derived from
sources which the Company reasonably and in good faith believes are reliable and
accurate, and such data agree with the sources from which they are derived.

         (q) The Company is subject to the reporting requirements of Section 13
or 15(d) of the Exchange Act and files reports with the Commission on the EDGAR
System. The Common Stock is registered pursuant to Section 12(b) of the Exchange
Act and the outstanding shares of Common Stock (other than the Shares) are
listed on NASDAQ (as defined in Section 9(b) below) and the Company has taken no
action designed to, or likely to have the effect of, terminating the
registration of the Common Stock under the Exchange Act or de-listing the Common
Stock from NASDAQ, nor has the Company received any notification that the
Commission or NASDAQ is contemplating terminating such registration or listing.

         (r) The Company and the Subsidiaries maintain a system of internal
accounting and other controls sufficient to provide reasonable assurances that
(i) transactions are


                                       6



executed in accordance with management's general or specific authorizations,
(ii) transactions are recorded as necessary to permit preparation of financial
statements in conformity with United States generally accepted accounting
principles and to maintain accountability for assets, (iii) access to assets is
permitted only in accordance with management's general or specific
authorization, and (iv) the recorded accounting for assets is compared with
existing assets at reasonable intervals and appropriate action is taken with
respect to any differences.

         (s) Neither the Company nor any of its affiliates (within the meaning
of Rule 144 under the Securities Act) has taken, directly or indirectly, any
action which constitutes or is designed to cause or result in, or which could
reasonably be expected to constitute, cause or result in, the stabilization or
manipulation of the price of any security to facilitate the sale or resale of
the Shares.

         (t) Neither Company nor any of its affiliates has, prior to the date
hereof, made any offer or sale of any securities which could be "integrated" for
purposes of the Securities Act or the Rules and Regulations with the offer and
sale of the Shares pursuant to the Registration Statement. Except as disclosed
in the Registration Statement and the Prospectus, neither Company nor any of its
affiliates has sold or issued any Relevant Security during the six-month period
preceding the date of the Prospectus, including but not limited to any sales
pursuant to Rule 144A or Regulation D or S under the Securities Act, other than
shares of Common Stock issued pursuant to employee benefit plans, qualified
stock option plans or the employee compensation plans or pursuant to outstanding
options, rights or warrants as described in the Registration Statement and the
Prospectus.

         (u) Except as disclosed in the Registration Statement and the
Prospectus, no holder of any Relevant Security has any rights to require
registration of any Relevant Security as part or on account of, or otherwise in
connection with, the offer and sale of the Shares contemplated hereby, and any
such rights so disclosed have either been fully complied with by the Company or
effectively waived by the holders thereof, and any such waivers remain in full
force and effect.

         (v) The conditions for use of Form S-3 to register the Offering under
the Securities Act, as set forth in the General Instructions to such Form, have
been satisfied.

         (w) The documents incorporated or deemed to be incorporated by
reference in the Prospectus, at the time they were or hereafter are filed with
the Commission, complied and will comply in all material respects with the
requirements of the Securities Act, the Exchange Act and the Rules and
Regulations, and, when read together with the other information in the
Prospectus, do not contain an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein, in the light of the circumstances under which they were
made, not misleading.

         (x) The Company is not and, at all times up to and including
consummation of the transactions contemplated by this Agreement, the
Registration Statement and the Prospectus, and after giving effect to
application of the net proceeds of the Offering, will not be, subject to
registration as an "investment company "under the Investment Company Act of
1940, as


                                       7



amended, and is not and will not be an entity "controlled" by an "investment
company" within the meaning of such act.

         (y) There are no contracts or other documents (including, without
limitation, any voting agreement), which are required to be described in the
Registration Statement and the Prospectus or filed as exhibits to the
Registration Statement by the Securities Act, the Exchange Act or the Rules and
Regulations and which have not been so described or filed.

         (z) No relationship, direct or indirect, exists between or among any of
the Company or any affiliate of the Company, on the one hand, and any director,
officer, stockholder, customer or supplier of the Company or any affiliate of
the Company, on the other hand, which is required by the Securities Act, the
Exchange Act or the Rules and Regulations to be described in the Registration
Statement or the Prospectus which is not so described as required. There are no
outstanding loans, advances (except normal advances for business expenses in the
ordinary course of business) or guarantees of indebtedness by the Company to or
for the benefit of any of the officers or directors of the Company or any of
their respective family members, except as disclosed in the Registration
Statement and the Prospectus. The Company has not, in violation of the
Sarbanes-Oxley Act, directly or indirectly, including through a Subsidiary,
extended or maintained credit, arranged for the extension of credit, or renewed
an extension of credit, in the form of a personal loan to or for any director or
executive officer of the Company.

         (aa) Except as disclosed in the Registration Statement and the
Prospectus, there are no contracts, agreements or understandings between the
Company and any person that would give rise to a valid claim against the Company
or the Underwriters for a brokerage commission, finder's fee or other like
payment in connection with the transactions contemplated by this Agreement, the
Registration Statement and the Prospectus or, to the Company's knowledge, any
arrangements, agreements, understandings, payments or issuance with respect to
the Company or any of its officers, directors, shareholders, partners,
employees, Subsidiaries or affiliates that may affect the Underwriters'
compensation as determined by the NASD.

         (bb) Except as set forth in the Registration Statement and the
Prospectus and except as could not reasonably be expected to have a Material
Adverse Effect, the Company and each Subsidiary (i) owns or possesses the right
to use all patents, patent applications, trademarks, service marks, trade names,
trademark registrations, service mark registrations, copyrights, licenses,
formulae, customer lists, and know-how and other intellectual property
(including trade secrets and other unpatented and/or unpatentable proprietary or
confidential information, systems or procedures, "Intellectual Property")
necessary to conduct their respective businesses as described in the
Registration Statement and Prospectus and (ii) have no reason to believe that
any activities of their respective businesses does or will conflict with, and
have not received any notice of any claim of conflict with, any such right of
others. Except as set forth in the Registration Statement and the Prospectus and
except as could not reasonably be expected to have a Material Adverse Effect, no
name which the Company or any of its subsidiaries uses and no other aspect or
activity of the business of the Company or any of its subsidiaries as conducted
on the date hereof involves or gives rise to any infringement of, or requires a
license or similar fees for rights to any Intellectual Property of others and
neither the Company nor any of its subsidiaries has received any notice alleging
any infringement or is aware of any allegations of


                                       8



infringement. The Company has duly filed or caused to be filed with the U.S.
Patent and Trademark Office (the "PTO") and applicable foreign and international
patent authorities all patent applications described in the Registration
Statement and the Prospectus and owned by the Company (the "Patent
Applications"). In connection with the filing of the Patent Applications at the
PTO and in other patent offices around the world, the Company has conducted
reasonable investigations of the published literature and patent references
relating to the inventions claimed in the Patent Applications and; to the best
of the Company's knowledge, the Company has complied with the PTO's duty of
candor and disclosure regarding prosecution of the Patent Applications and made
no misrepresentation in the Patent Applications; Except as set forth in the
Registration Statement and the Prospectus and except as could not reasonably be
expected to have a Material Adverse Effect, the Company is not aware of any
facts material to a determination of patentability regarding the Patent
Applications not called to the attention of the PTO that would preclude the
grant of a patent for the Patent Applications; and the Company has secured with
appropriate legal instruments clear title to the Patent Applications and has no
knowledge of any facts which would adversely affect the Patent Applications.

         (cc) The Company and the Subsidiaries maintain insurance in such
amounts and covering such risks as the Company reasonably considers adequate for
the conduct of its business and the value of its properties, all of which
insurance is in full force and effect, except where the failure to maintain such
insurance could not reasonably be expected to have a Material Adverse Effect.
There are no material claims by the Company or any Subsidiary under any such
policy or instrument as to which any insurance company is denying liability or
defending under a reservation of rights clause. The Company reasonably believes
that it will be able to renew its existing insurance as and when such coverage
expires or will be able to obtain replacement insurance adequate for the conduct
of the business and the value of its properties at a cost that could not
reasonably be expected to have a Material Adverse Effect.

         (dd) The Company has in effect insurance covering the Company, its
directors, and officers for liabilities or losses arising in connection with
this Offering, including, without limitation, liabilities or losses arising
under the Securities Act, the Exchange Act, the Rules and Regulations and
applicable foreign securities laws.

         (ee) Each of the Company and the Subsidiaries has accurately prepared
and timely filed all federal, state, foreign, franchise and other tax returns
that are required to be filed by it and has paid or made provision for the
payment of all taxes, assessments, governmental or other similar charges,
including without limitation, all sales and use taxes and all taxes which the
Company or any Subsidiary is obligated to withhold from amounts owing to
employees, creditors and third parties, with respect to the periods covered by
such tax returns (whether or not such amounts are shown as due on any tax
return), except in such case where such failure to file or pay or withhold could
not reasonably be expected to have a Material Adverse Effect. No deficiency
assessment with respect to a proposed adjustment of the Company's or any
Subsidiary' federal, state, local, foreign or franchise taxes is pending or, to
the best of the Company's knowledge, threatened. The accruals and reserves on
the books and records of the Company and the Subsidiaries in respect of tax
liabilities for any taxable period not finally determined are adequate to meet
any assessments and related liabilities for any such period and, since July 31,
2002, the Company and the Subsidiaries have not incurred any liability for taxes
other than in the ordinary course of its business. There is no tax lien, whether
imposed by any


                                       9



federal, state, foreign, franchise or other taxing authority, outstanding
against the assets, properties or business of the Company or any Subsidiary.

         (ff) No labor disturbance by the employees of the Company or any
Subsidiary exists or, to the best of the Company's knowledge, is imminent.

         (gg) No "prohibited transaction" (as defined in either Section 406 of
the Employee Retirement Income Security Act of 1974, as amended, including the
regulations and published interpretations thereunder ("ERISA") or Section 4975
of the Internal Revenue Code of 1986, as amended from time to time (the
"Code")), "accumulated funding deficiency" (as defined in Section 302 of ERISA)
or other event of the kind described in Section 4043(b) of ERISA (other than
events with respect to which the 30-day notice requirement under Section 4043 of
ERISA has been waived) has occurred with respect to any employee benefit plan
for which the Company or any Subsidiary would have any liability which could,
individually or in the aggregate, reasonably be expected to have a Material
Adverse Effect; each employee benefit plan for which the Company or any
Subsidiary would have any liability is in compliance in all material respects
with applicable law, including (without limitation) ERISA and the Code; the
Company has not incurred and does not expect to incur material liability under
Title IV of ERISA with respect to the termination of, or withdrawal from any
"pension plan"; and each plan for which the Company would have any liability
that is intended to be qualified under Section 401(a) of the Code is so
qualified and nothing has occurred, whether by action or by failure to act,
which could cause the loss of such qualification.

         (hh) There has been no storage, generation, transportation, handling,
treatment, disposal, discharge, emission or other release of any kind of toxic
or other wastes or other hazardous substances by the Company or any Subsidiary
(or, to the Company's knowledge, any other entity for whose acts or omissions
the Company is or may be liable) upon any other property now or previously owned
or leased by the Company or any Subsidiary, or upon any other property, which
would be a violation of or give rise to any liability under any applicable law,
rule, regulation, order, judgment, decree or permit relating to pollution or
protection of human health and the environment ("Environmental Law"), except for
violations and liabilities which, individually or in the aggregate, could not
reasonably be expected to have a Material Adverse Effect. There has been no
disposal discharge, emission or other release of any kind onto such property or
into the environment surrounding such property of any toxic or other wastes or
other hazardous substances with respect to which the Company or any Subsidiary
has knowledge, except as could not, individually or in the aggregate, reasonably
be expected to have a Material Adverse Effect. Neither the Company nor any
Subsidiary has agreed to assume, undertake or provide indemnification for any
liability of any other person under any Environmental Law, including any
obligation for cleanup or remedial action, except as could not, individually or
in the aggregate, reasonably be expected to have a Material Adverse Effect.
There is no pending or, to the best of the Company's knowledge, threatened
administrative, regulatory or judicial action, claim or notice of noncompliance
or violation, investigation or proceedings relating to any Environmental Law
against the Company or any Subsidiary.

         (ii) Neither the Company, any Subsidiary nor, to the Company's
knowledge, any of its officers or agents has at any time during the last five
years (i) made any unlawful contribution to any candidate for foreign office, or
failed to disclose fully any contribution in


                                       10



violation of law, or (ii) made any payment to any federal or state governmental
officer or official, or other person charged with similar public or quasi-public
duties, other than payments required or permitted by the laws of the United
States of any jurisdiction thereof.

         (jj) Neither the Company nor any Subsidiary (i) is in violation of its
certificate or articles of incorporation, by-laws, certificate of formation,
limited liability company agreement, partnership agreement or other
organizational documents, (ii) is in default under, and no event has occurred
which, with notice or lapse of time or both, would constitute a default under or
result in the creation or imposition of any lien, charge or encumbrance upon any
of its property or assets pursuant to, any indenture, mortgage, deed of trust,
loan agreement or other agreement or instrument to which it is a party or by
which it is bound or to which any of its property or assets is subject or (iii)
is in violation in any respect of any law, rule, regulation, ordinance,
directive, judgment, decree or order of any judicial, regulatory or other legal
or governmental agency or body, foreign or domestic, except (in the case of
clauses (ii) and (iii) above) violations or defaults that could not,
individually or in the aggregate, reasonably be expected to have a Material
Adverse Effect on the Company and its Subsidiaries taken as a whole and except
(in the case of clause (ii) alone) for any lien, charge or encumbrance disclosed
in the Registration Statement and the Prospectus.

         (kk) Except as described in the Prospectus, as of the date hereof, each
of the Company and its Subsidiaries has enforceable leases for all of the
properties and assets, real or personal, described in the Registration Statement
and Prospectus as leased by them, in each case free and clear of any security
interests, mortgages, pledges, liens, encumbrances or charges of any kind, other
than those described in the Prospectus and those that could not, individually or
in the aggregate, reasonably be expected to have a Material Adverse Effect.

         (ll) The Company is in compliance with applicable provisions of the
Sarbanes-Oxley Act that are effective and is actively taking steps to ensure
that it will be in compliance with other applicable provisions of the
Sarbanes-Oxley Act upon the effectiveness of such provisions.

         (mm) The Company has established and maintains "disclosure controls and
procedures" (as defined in Rules 13a-14(c) and 15d-14(c) of the Exchange Act);
the Company's "disclosure controls and procedures" are reasonably designed to
ensure that all information (both financial and non-financial) required to be
disclosed by the Company in the reports that it files or submits under the
Exchange Act is recorded, processed, summarized and reported within the time
periods specified in the Rules and Regulations, and that all such information is
accumulated and communicated to the Company's management as appropriate to allow
timely decisions regarding required disclosure and to make the certifications of
the Chief Executive Officer and Chief Financial Officer of the Company required
under the Exchange Act with respect to such reports.

         (nn) Since the date of the filing of the Company's Annual Report on
Form 10-K for the year ended July 31, 2002, the Company's auditors and the audit
committee of the board of directors of the Company (or persons fulfilling the
equivalent function) have not been advised of (i) any significant deficiencies
in the design or operation of internal controls which could adversely affect the
Company's ability to record, process, summarize and report financial data


                                       11



nor any material weaknesses in internal controls; (ii) any fraud, whether or not
material, that involves management or other employees who have a significant
role in the Company's internal controls.

         (oo) Since the date of the filing of the Company's Annual Report on
Form 10-K for the year ended July 31, 2002, there have been no significant
changes in internal controls or in other factors that could significantly affect
internal controls, including any corrective actions with regard to significant
deficiencies and material weaknesses.

         (pp) The Company's board of directors, senior management and audit
committee have reviewed and agreed with the selection, application and
disclosure of critical accounting policies and have consulted with their legal
advisers and independent accountants with regard to such disclosure.

         (qq) Except as disclosed in the Registration and the Prospectus, there
are no outstanding guarantees or other contingent obligations of the Company or
any Subsidiary that could reasonably be expected to have a Material Adverse
Effect.

         (rr) The Company and the Subsidiaries are not presently doing business
with the government of Cuba.

         Any certificate signed by or on behalf of the Company and delivered to
the Underwriters or to counsel for the Underwriters shall be deemed to be a
representation and warranty by the Company to the Underwriters as to the matters
covered thereby.

         2. Purchase, Sale and Delivery of the Shares.

            (a) On the basis of the representations, warranties, covenants and
agreements herein contained, but subject to the terms and conditions herein set
forth, the Company agrees to sell to each Underwriters and each Underwriter,
severally and not jointly, agrees to purchase from the Company, at a purchase
price per share of $12.22, the number of Shares set forth opposite such
Underwriter's name on Schedule I attached hereto, together with any additional
number of Shares which such Underwriter may become obligated to purchase
pursuant to the provisions of Section 9 hereof.

            (b) Payment of the purchase price for, and delivery of certificates
representing, the Shares shall be made at the office of Morrison & Foerster LLP,
1290 Avenue of the Americas, New York, New York, 10104 ("Underwriters'
Counsel"), or at such other place as shall be agreed upon by the Representative
and the Company, at 10:00 A.M., New York City time, on September 17, 2003 or
such other time not later than 5 business days after such date as shall be
agreed upon by the Representative and the Company (such time and date of payment
and delivery being herein called the "Closing Date").

         Payment of the purchase price for the Shares shall be made by wire
transfer in same day funds to or as directed by the Company upon delivery of
certificates for the Shares to the Underwriters through the facilities of The
Depository Trust Company for the respective accounts of the several
Underwriters. Certificates for the Shares shall be registered in such name or
names and shall be in such denominations as the Representative may request at
least two


                                       12



business days before the Closing Date. The Company will permit the
Representative to examine and package such certificates for delivery at least
one full business day prior to the Closing Date.

         3. Offering. Upon authorization of the release of the Shares by the
Representative, the Underwriters propose to offer the Shares for sale to the
public upon the terms and conditions set forth in the Prospectus.

         4. Covenants of the Company. The Company covenants and agrees with the
Underwriters that:

            (a) The Registration Statement and any amendments thereto have been
declared effective, and if Rule 430A is used or the filing of the Prospectus
otherwise is required under Rule 424(b) or Rule 434, the Company will file the
Prospectus (properly completed if Rule 430A has been used) pursuant to Rule
424(b) within the prescribed time period and will provide evidence satisfactory
to the Representative of such timely filing. If the Company elects to rely on
Rule 434, the Company will prepare and file a term sheet that complies with the
requirements of Rule 434, and the Prospectus shall not be "materially different"
(as such term is used in Rule 434) from the Prospectus included in the
Registration Statement at the time it became effective.

         The Company will notify you immediately (and, if requested by the
Representative, will confirm such notice in writing) (i) of any request by the
Commission for any amendment of or supplement to the Registration Statement or
the Prospectus or for any additional information, (ii) of the Company's
intention to file or prepare any supplement or amendment to the Registration
Statement or the Prospectus, (iii) of the mailing or the delivery to the
Commission for filing of any amendment of or supplement to the Registration
Statement or the Prospectus, (iv) of the issuance by the Commission of any stop
order suspending the effectiveness of the Registration Statement or any
post-effective amendment thereto or of the initiation, or the threatening, of
any proceedings therefor, it being understood that the Company shall make every
effort to avoid the issuance of any such stop order, (v) of the receipt of any
comments from the Commission, and (vi) of the receipt by the Company of any
notification with respect to the suspension of the qualification of the Shares
for sale in any jurisdiction or the initiation or threatening of any proceeding
for that purpose. If the Commission shall propose or enter a stop order at any
time, the Company will make every reasonable effort to prevent the issuance of
any such stop order and, if issued, to obtain the lifting of such order as soon
as possible. The Company will not file any amendment to the Registration
Statement or any amendment of or supplement to the Prospectus (including the
prospectus required to be filed pursuant to Rule 424(b) or Rule 434) that
differs from the prospectus on file at the time of the effectiveness of the
Registration Statement or file any document under the Exchange Act if such
document would be deemed to be incorporated by reference into the Prospectus to
which the Representative shall object in writing after being timely furnished in
advance a copy thereof. The Company will provide the Representative with copies
of all such amendments, filings and other documents a sufficient time prior to
any filing or other publication thereof to permit the Representative a
reasonable opportunity to review and comment thereon.

            (b) The Company shall comply with the Securities Act and the
Exchange Act to permit completion of the distribution as contemplated in this
Agreement, the Registration Statement and the Prospectus. If at any time when a
prospectus relating to the Shares is required


                                       13



to be delivered under the Securities Act or the Exchange Act in connection with
the sales of Shares, any event shall have occurred as a result of which the
Prospectus as then amended or supplemented would, in the judgment of the
Representative or the Company, include an untrue statement of a material fact or
omit to state any material fact required to be stated therein or necessary to
make the statements therein, in the light of the circumstances existing at the
time of delivery to the purchaser, not misleading, or if to comply with the
Securities Act, the Exchange Act or the Rules and Regulations it shall be
necessary at any time to amend or supplement the Prospectus or Registration
Statement, or to file any document incorporated by reference in the Registration
Statement or the Prospectus or in any amendment thereof or supplement thereto,
the Company will notify you promptly and prepare and file with the Commission,
subject to Section 4(a) hereof, an appropriate amendment or supplement (in form
and substance satisfactory to the Representative) which will correct such
statement or omission or which will effect such compliance and will use its best
efforts to have any amendment to the Registration Statement declared effective
as soon as possible.

            (c) Prior to 10:00 A.M., New York time, on the business day next
succeeding the date of this Agreement and from time to time thereafter, the
Company will furnish the Underwriters with copies of the Prospectus in New York
City in such quantities as you may reasonably request.

            (d) The Company will use its best efforts, in cooperation with the
Representative, to qualify the Shares for offering and sale under the securities
laws relating to the offering or sale of the Shares of such jurisdictions,
domestic or foreign, as the Representative may designate and to maintain such
qualification in effect for so long as required for the distribution thereof;
except that in no event shall the Company be obligated in connection therewith
to qualify as a foreign corporation or to execute a general consent to service
of process.

            (e) The Company will make generally available to its security
holders and to the Underwriters as soon as practicable an earnings statement of
the Company and the Subsidiaries (which need not be audited) complying with
Section 11(a) of the Securities Act and the Rules and Regulations (including, at
the option of the Company, Rule 158).

            (f) During the period of 90 days from the date of the Prospectus,
without the prior written consent of the Representative, the Company (i) will
not, directly or indirectly, issue, offer, sell, agree to issue, offer or sell,
solicit offers to purchase, grant any call option, warrant or other right to
purchase, purchase any put option or other right to sell, pledge, borrow or
otherwise dispose of any Relevant Security, or make any announcement of any of
the foregoing, (ii) will not establish or increase any "put equivalent position"
or liquidate or decrease any "call equivalent position" (in each case within the
meaning of Section 16 of the Exchange Act and the rules and regulations
promulgated thereunder) with respect to any Relevant Security, and (iii) will
not otherwise enter into any swap, derivative or other transaction or
arrangement that transfers to another, in whole or in part, any economic
consequence of ownership of a Relevant Security, whether or not such transaction
is to be settled by delivery of Relevant Securities, other securities, cash or
other consideration; and the Company will obtain an undertaking in substantially
the form of Annex III hereto of each of its executive officers and directors not
to engage in any of the aforementioned transactions on their own behalf, other
than the sale of Shares as contemplated by this Agreement and the Company's
issuance of Common Stock upon


                                       14



(i) the conversion or exchange of convertible or exchangeable securities
outstanding on the date hereof; (ii) the exercise of currently outstanding
options; (iii) the exercise of currently outstanding warrants; and (iv) the
grant and exercise of options under, or the issuance and sale of shares pursuant
to, employee stock option plans in effect on the date hereof, each as described
in the Registration Statement and the Prospectus. The Company will not file a
registration statement under the Securities Act in connection with any
transaction by the Company or any person that is prohibited pursuant to the
foregoing, except for registration statements on Form S-8 relating to employee
benefit plans or Form S-4 relating to corporate reorganizations or other
transactions under Rule 145.

            (g) During the period of two years from the date of this Agreement,
the Company will furnish to you copies of all reports or other communications
(financial or other) furnished to securityholders or from time to time published
or publicly disseminated by the Company, and will deliver to you (i) as soon as
they are available, copies of any reports, financial statements and proxy or
information statements furnished to or filed with the Commission or any national
securities exchange on which any class of securities of the Company is listed;
and (ii) such additional information concerning the business and financial
condition of the Company as you may from time to time reasonably request (such
financial information to be on a consolidated basis to the extent the accounts
of the Company and the Subsidiaries are consolidated in reports furnished to its
security holders generally or to the Commission).

            (h) The Company will apply the net proceeds from the sale of the
Shares asset forth under the caption "Use of Proceeds" in the Prospectus.

            (i) The Company will use its best efforts to list the Shares on
NASDAQ and maintain the listing of the Shares on NASDAQ.

            (j) The Company, during the period when the Prospectus is required
to be delivered under the Securities Act or the Exchange Act, will file all
documents required to be filed with the Commission pursuant to the Securities
Act the Exchange Act and the Rules and Regulations within the time periods
required thereby.

            (k) The Company will use its best efforts to do and perform all
things required to be done or performed under this Agreement by the Company
prior to the Closing Date, as the case may be, and to satisfy all conditions
precedent to the delivery of the Shares.

            (l) The Company will not take, and will cause its affiliates (within
the meaning of Rule 144 under the Securities Act) not to take, directly or
indirectly, any action which constitutes or is designed to cause or result in,
or which could reasonably be expected to constitute, cause or result in, the
stabilization or manipulation of the price of any security to facilitate the
sale or resale of the Shares.

         5. Payment of Expenses. Whether or not the transactions contemplated by
this Agreement, the Registration Statement and the Prospectus are consummated or
this Agreement is terminated, the Company hereby agrees to pay all costs and
expenses incident to the performance of its obligations hereunder, including the
following: (i) all expenses in connection with the preparation, printing and
filing of the Registration Statement and the Prospectus and any and all


                                       15



amendments and supplements thereto and the mailing and delivering of copies
thereof to the Underwriters and dealers; (ii) the fees, disbursements and
expenses of the Company's counsel and accountants in connection with the
registration of the Shares under the Securities Act and the Offering; (iii) the
cost of producing this Agreement and any agreement among Underwriters, blue sky
survey, closing documents and other instruments, agreements or documents
(including any compilations thereof) in connection with the Offering; (iv) all
expenses in connection with the qualification of the Shares for offering and
sale under state or foreign securities or blue sky laws as provided in Section
4(d) hereof, including the fees and disbursements of counsel for the
Underwriters in connection with such qualification and in connection with any
blue sky survey; (v) the filing fees incident to, and the fees and disbursements
of counsel for the Underwriters in connection with, securing any required review
by the NASD of the terms of the Offering; (vi) all fees and expenses in
connection with listing the Shares on NASDAQ; (vii) all travel expenses of the
Company's officers and employees and any other expense of the Company incurred
in connection with attending or hosting meetings with prospective purchasers of
the Shares; and (viii) any stock transfer taxes incurred in connection with this
Agreement or the Offering. The Company also will pay or cause to be paid: (x)
the cost of preparing stock certificates representing the Shares; (y) the cost
and charges of any transfer agent or registrar for the Shares; and (z) all other
costs and expenses incident to the performance of its obligations hereunder
which are not otherwise specifically provided for in this Section 5. It is
understood, however, that except as provided in this Section, and Sections 7, 8
and 11 hereof, the Underwriters will pay all of their own costs and expenses,
including the fees of their counsel and stock transfer taxes on resale of any of
the Shares by them. Notwithstanding anything to the contrary in this Section 5,
in the event that this Agreement is terminated pursuant to Section 6 or 11(b)
hereof, or subsequent to a Material Adverse Change, the Company will pay all
out-of pocket expenses of the Underwriters (including but not limited to fees
and disbursements of counsel to the Underwriters) incurred in connection
herewith.

         6. Conditions of Underwriters' Obligations. The obligations of the
Underwriters to purchase and pay for the Shares, as provided herein, shall be
subject to the accuracy of the representations and warranties of the Company
herein contained, as of the date hereof and as of the Closing Date, to the
absence from any certificates, opinions, written statements or letters furnished
to you or to Underwriters' Counsel pursuant to this Section 6 of any
misstatement or omission, to the performance by the Company of its obligations
hereunder, and to each of the following additional conditions:

            (a) The Prospectus shall have been filed with the Commission in a
timely fashion in accordance with Section 4(a) hereof and a form of the
Prospectus containing information relating to the description of the Shares and
the method of distribution and similar matters shall have been filed with the
Commission pursuant to Rule 424(b) within the applicable time period; and, at or
prior to the Closing Date no stop order suspending the effectiveness of the
Registration Statement or any post-effective amendment thereof shall have been
issued and no proceedings therefor shall have been initiated or threatened by
the Commission.

            (b) At the Closing Date you shall have received:


                                       16



                (i)  An opinion, dated the Closing Date, of Fulbright & Jaworski
                L.L.P., counsel for the Company, substantially in the form set
                forth in Annex I attached hereto.

                (ii) An opinion, dated the Closing Date of Mark Farber,
                intellectual property counsel for the Company, substantially in
                the form set forth in Annex II attached hereto.

            (c) All proceedings taken in connection with the sale of the Shares
as herein contemplated shall be satisfactory in form and substance to the
Representative and to Underwriters' Counsel, and the Underwriters shall have
received from Underwriters' Counsel a favorable written opinion, dated as of the
Closing Date, with respect to the issuance and sale of the Shares, the
Registration Statement and the Prospectus and such other related matters as the
Underwriters may require, and the Company shall have furnished to Underwriters'
Counsel such documents as they may reasonably request for the purpose of
enabling them to pass upon such matters.

            (d) At the Closing Date you shall have received a certificate of the
Chief Executive Officer and Chief Financial Officer of the Company, dated the
Closing Date to the effect that (i) the condition set forth in subsection (a) of
this Section 6 has been satisfied, (ii) as of the date hereof and as of the
Closing Date, the representations and warranties of the Company set forth in
Section 1 hereof are accurate, (iii) as of the Closing Date all agreements,
conditions and obligations of the Company to be performed or complied with
hereunder on or prior thereto have been duly performed or complied with, (iv)
the Company and the Subsidiaries have not sustained any material loss or
interference with their respective businesses or properties from fire, flood,
hurricane, accident or other calamity, whether or not covered by insurance, or
from any labor dispute or any legal or governmental proceeding, (v) no stop
order suspending the effectiveness of the Registration Statement or any
post-effective amendment thereof has been issued and no proceedings therefor
have been initiated or threatened by the Commission, (vi) there are no pro forma
or as adjusted financial statements that are required to be included in the
Registration Statement and the Prospectus pursuant to the Rules and Regulations
that have not been included as required and (vii) subsequent to the respective
dates as of which information is given in the Registration Statement and the
Prospectus there has not been any material adverse change or any development
involving a prospective Material Adverse Change, whether or not arising from
transactions in the ordinary course of business, in or affecting (x) the
business, condition (financial or otherwise), results of operations,
stockholders' equity, properties or prospects of the Company and the
Subsidiaries taken as a whole; (y) the long-term debt or capital stock of the
Company and its Subsidiaries taken as a whole; or (z) the Offering or
consummation of any of the other transactions contemplated by this Agreement,
the Registration Statement and the Prospectus.

            (e) At the time this Agreement is executed and at the Closing Date,
you shall have received a comfort letter, from PricewaterhouseCoopers L.L.P.,
independent public accountants for the Company, dated respectively, as of the
date of this Agreement and as of the Closing Date addressed to the Underwriters
and in form and substance satisfactory to the Representative and Underwriters'
Counsel.


                                       17



            (f) Subsequent to the execution and delivery of this Agreement or,
if earlier, the dates as of which information is given in the Registration
Statement (exclusive of any amendment thereof) and the Prospectus (exclusive of
any supplement thereto), there shall not have been any change in the capital
stock or long-term debt of the Company and its Subsidiaries taken as a whole or
any change or development involving a change, whether or not arising from
transactions in the ordinary course of business, in the business, condition
(financial or otherwise), results of operations, stockholders' equity,
properties or prospects of the Company and the Subsidiaries, individually or
taken as a whole, including but not limited to the occurrence of any fire,
flood, storm, explosion, accident or other calamity at any of the properties
owned or leased by the Company or any of its Subsidiaries, the effect of which,
in any such case described above, is, in the judgment of the Representative, so
material and adverse as to make it impracticable or inadvisable to proceed with
the Offering on the terms and in the manner contemplated in the Prospectus
(exclusive of any supplement).

            (g) No downgrading shall have occurred in the Company's corporate
credit rating or the rating accorded the Company's debt securities or preferred
stock by any "nationally recognized statistical rating organization" (as defined
for purposes of Rule 436(g) under the Securities Act) and no such organization
shall have publicly announced that it has under surveillance or review, with
possible negative implications, its rating of any of the Company's debt
securities.

            (h) You shall have received a duly executed lock-up agreement from
each person who is a director or executive officer of the Company, in each case
substantially in the form attached hereto as Annex III.

            (i) At the Closing Date, the Shares shall have been approved for
listing on NASDAQ.

            (j) No action shall have been taken and no statute, rule, regulation
or order shall have been enacted, adopted or issued by any federal, state or
foreign governmental or regulatory authority that would, as of the Closing Date,
prevent the issuance or sale of the Shares; and no injunction or order of any
federal, state or foreign court shall have been issued that would, as of the
Closing Date, prevent the issuance or sale of the Shares.

            (k) The Company shall have furnished the Underwriters and
Underwriters' Counsel with such other certificates, opinions or other documents
as they may have reasonably requested.

         If any of the conditions specified in this Section 6 shall not have
been fulfilled when and as required by this Agreement, or if any of the
certificates, opinions, written statements or letters furnished to you or to
Underwriters' Counsel pursuant to this Section 6 shall not be satisfactory in
form and substance to the Representative and to Underwriters' Counsel, all
obligations of the Underwriters hereunder may be cancelled by the Representative
at, or at any time prior to, the Closing Date. Notice of such cancellation shall
be given to the Company in writing, or by telephone. Any such telephone notice
shall be confirmed promptly thereafter in writing.

         7. Indemnification.


                                       18



            (a) The Company shall indemnify and hold harmless each Underwriter
and each person, if any, who controls any Underwriter within the meaning of
Section 15 of the Securities Act or Section 20 of the Exchange Act, against any
and all losses, liabilities, claims, damages and expenses whatsoever as incurred
(including but not limited to attorneys' fees and any and all expenses
whatsoever incurred in investigating, preparing or defending against any
litigation, commenced or threatened, or any claim whatsoever, and any and all
amounts paid in settlement of any claim or litigation), joint or several, to
which they or any of them may become subject under the Securities Act, the
Exchange Act or otherwise, insofar as such losses, liabilities, claims, damages
or expenses (or actions in respect thereof) arise out of or are based upon (i)
any untrue statement or alleged untrue statement of a material fact contained in
the Registration Statement, as originally filed or any amendment thereof or the
Prospectus, or in any supplement thereto or amendment thereof, or (ii) the
omission or alleged omission to state in the Registration Statement, as
originally filed or any amendment thereof or the Prospectus, or in any
supplement thereto or amendment thereof, a material fact required to be stated
therein or necessary to make the statements therein not misleading; provided,
however, that the Company will not be liable in any such case to the extent but
only to the extent that any such loss, liability, claim, damage or expense
arises out of or is based upon any untrue statement or alleged untrue statement
or omission or alleged omission made in the Registration Statement, as
originally filed or any amendment thereof or the Prospectus, or in any
supplement thereto or amendment thereof, in reliance upon and in conformity with
written information furnished to the Company by or on behalf of any Underwriter
through the Representative expressly for use therein. The parties agree that
such information provided by or on behalf of any Underwriter through the
Representative consists solely of the material referred to in the last sentence
of Section 1(b) hereof. This indemnity agreement will be in addition to any
liability which the Company may otherwise have, including but not limited to
other liability under this Agreement.

            (b) Each Underwriter, severally and not jointly, shall indemnify and
hold harmless the Company, each of the directors of the Company, each of the
officers of the Company who shall have signed the Registration Statement, and
each other person, if any, who controls the Company within the meaning of
Section 15 of the Securities Act or Section 20 of the Exchange Act, against any
losses, liabilities, claims, damages and expenses whatsoever as incurred
(including but not limited to attorneys' fees and any and all expenses
whatsoever incurred in investigating, preparing or defending against any
litigation, commenced or threatened, or any claim whatsoever, and any and all
amounts paid in settlement of any claim or litigation), joint or several, to
which they or any of them may become subject under the Securities Act, the
Exchange Act or otherwise, insofar as such losses, liabilities, claims, damages
or expenses (or actions in respect thereof) arise out of or are based upon any
untrue statement or alleged untrue statement of a material fact contained in the
Registration Statement, as originally filed or any amendment thereof or the
Prospectus, or in any amendment thereof or supplement thereto, or arise out of
or are based upon the omission or alleged omission to state therein a material
fact required to be stated therein or necessary to make the statements therein
not misleading, in each case to the extent, but only to the extent, that any
such loss, liability, claim, damage or expense arises out of or is based upon
any such untrue statement or alleged untrue statement or omission or alleged
omission made therein in reliance upon and in conformity with information
furnished in writing to the Company by or on behalf of any Underwriter through
the Representative specifically for use therein; provided, however, that in no
case shall any Underwriter be liable or responsible for any amount in excess of
the underwriting discount


                                       19



applicable to the Shares to be purchased by such Underwriter hereunder. The
parties agree that such information provided by or on behalf of any Underwriter
through the Representative consists solely of the material referred to in the
last sentence of Section 1(b) hereof. This indemnity will be in addition to any
liability which any Underwriter may otherwise have, including but not limited to
other liability under this Agreement.

            (c) Promptly after receipt by an indemnified party under subsection
(a) or (b) above of notice of any claims or the commencement of any action, such
indemnified party shall, if a claim in respect thereof is to be made against the
indemnifying party under such subsection, notify each party against whom
indemnification is to be sought in writing of the claim or the commencement
thereof (but the failure so to notify an indemnifying party shall not relieve
the indemnifying party from any liability which it may have under this Section 7
to the extent that it is not materially prejudiced as a result thereof and in
any event shall not relieve it from any liability that such indemnifying party
may have otherwise than on account of the indemnity agreement hereunder). In
case any such claim or action is brought against any indemnified party, and it
notifies an indemnifying party of the commencement thereof, the indemnifying
party will be entitled to participate, at its own expense in the defense of such
action, and to the extent it may elect by written notice delivered to the
indemnified party promptly after receiving the aforesaid notice from such
indemnified party, to assume the defense thereof with counsel satisfactory to
such indemnified party; provided however, that counsel to the indemnifying party
shall not (except with the written consent of the indemnified party) also be
counsel to the indemnified party. Notwithstanding the foregoing, the indemnified
party or parties shall have the right to employ its or their own counsel in any
such case, but the fees and expenses of such counsel shall be at the expense of
such indemnified party or parties unless (i) the employment of such counsel
shall have been authorized in writing by one of the indemnifying parties in
connection with the defense of such action, (ii) the indemnifying parties shall
not have employed counsel to have charge of the defense of such action within a
reasonable time after notice of commencement of the action, (iii) the
indemnifying party does not diligently defend the action after assumption of the
defense, or (iv) such indemnified party or parties shall have reasonably
concluded that there may be defenses available to it or them which are different
from or additional to those available to one or all of the indemnifying parties
(in which case the indemnifying parties shall not have the right to direct the
defense of such action on behalf of the indemnified party or parties), in any of
which events such fees and expenses shall be borne by the indemnifying parties.
No indemnifying party shall, without the prior written consent of the
indemnified parties, effect any settlement or compromise of, or consent to the
entry of judgment with respect to, any pending or threatened claim,
investigation, action or proceeding in respect of which indemnity or
contribution may be or could have been sought by an indemnified party under this
Section 7 or Section 8 hereof (whether or not the indemnified party is an actual
or potential party thereto), unless (x) such settlement, compromise or judgment
(i) includes an unconditional release of the indemnified party from all
liability arising out of such claim, investigation, action or proceeding and
(ii) does not include a statement as to or an admission of fault, culpability or
any failure to act, by or on behalf of the indemnified party, and (y) the
indemnifying party confirms in writing its indemnification obligations hereunder
with respect to such settlement, compromise or judgment.

         8. Contribution. In order to provide for contribution in circumstances
in which the indemnification provided for in Section 7 hereof is for any reason
held to be unavailable from


                                       20



any indemnifying party or is insufficient to hold harmless a party indemnified
thereunder, the Company and the Underwriters shall contribute to the aggregate
losses, claims, damages, liabilities and expenses of the nature contemplated by
such indemnification provision (including any investigation, legal and other
expenses incurred in connection with, and any amount paid in settlement of, any
action, suit or proceeding or any claims asserted, but after deducting in the
case of losses, claims, damages, liabilities and expenses suffered by the
Company, any contribution received by the Company from persons, other than the
Underwriters, who may also be liable for contribution, including persons who
control the Company within the meaning of Section 15 of the Securities Act or
Section 20 of the Exchange Act, officers of the Company who signed the
Registration Statement and directors of the Company) as incurred to which the
Company and one or more of the Underwriters may be subject, in such proportions
as is appropriate to reflect the relative benefits received by the Company and
the Underwriters from the Offering or, if such allocation is not permitted by
applicable law, in such proportions as are appropriate to reflect not only the
relative benefits referred to above but also the relative fault of the Company
and the Underwriters in connection with the statements or omissions which
resulted in such losses, claims, damages, liabilities or expenses, as well as
any other relevant equitable considerations. The relative benefits received by
the Company and the Underwriters shall be deemed to be in the same proportion as
(x) the total proceeds from the Offering (net of underwriting discounts and
commissions but before deducting expenses) received by the Company bears to (y)
the underwriting discount or commissions received by the Underwriters, in each
case as set forth in the table on the cover page of the Prospectus. The relative
fault of each of the Company and of the Underwriters shall be determined by
reference to, among other things, whether the untrue or alleged untrue statement
of a material fact or the omission or alleged omission to state a material fact
relates to information supplied by the Company or the Underwriters and the
parties' relative intent, knowledge, access to information and opportunity to
correct or prevent such statement or omission. The Company and the Underwriters
further agree that it would not be just and equitable if contribution pursuant
to this Section 8 were determined by pro rata allocation (even if the
Underwriters were treated as one entity for such purpose) or by any other method
of allocation which does not take account of the equitable considerations
referred to above in this Section. The aggregate amount of losses, liabilities,
claims, damages and expenses incurred by an indemnified party and referred to
above in this Section 8 shall be deemed to include any legal or other expenses
reasonably incurred by such indemnified party in investigating, preparing or
defending against any litigation, or any investigation or proceeding by any
judicial, regulatory or other legal or governmental agency or body, commenced or
threatened, or any claim whatsoever based upon any such untrue or alleged untrue
statement or omission or alleged omission. Notwithstanding the provisions of
this Section 8, (i) no Underwriter shall be required to contribute any amount in
excess of the amount by which the discounts and commissions applicable to the
Shares underwritten by it and distributed to the public exceeds the amount of
any damages which such Underwriter has otherwise been required to pay by reason
of such untrue or alleged untrue statement or omission or alleged omission and
(ii) no person guilty of fraudulent misrepresentation (within the meaning of
Section 10(f) of the Securities Act) shall be entitled to contribution from any
person who was not guilty of such fraudulent misrepresentation. For purposes of
this Section 8, each person, if any, who controls an Underwriter within the
meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act
shall have the same rights to contribution as such Underwriter, and each person,
if any, who controls the Company within the meaning of Section 15 of the
Securities Act


                                       21



or Section 20 of the Exchange Act, each officer of the Company who shall have
signed the Registration Statement and each director of the Company shall have
the same rights to contribution as the Company, subject in each case to clauses
(i) and (ii) of the immediately preceding sentence. Any party entitled to
contribution will, promptly after receipt of notice of commencement of any
action, suit or proceeding against such party in respect of which a claim for
contribution may be made against another party or parties, notify each party or
parties from whom contribution may be sought, but the omission to so notify such
party or parties shall not relieve the party or parties from whom contribution
may be sought from any obligation it or they may have under this Section 8 or
otherwise. The obligations of the Underwriters to contribute pursuant to this
Section 8 are several in proportion to the respective number of Shares to be
purchased by each of the Underwriters hereunder and not joint.

         9. Underwriter Default.

            (a) If any Underwriter or Underwriters shall default in its or their
obligation to purchase Shares hereunder, and if the Shares with respect to which
such default relates (the "Default Shares") do not (after giving effect to
arrangements, if any, made by the Representative pursuant to subsection (b)
below) exceed in the aggregate 10% of the number of Shares, each non-defaulting
Underwriter, acting severally and not jointly, agrees to purchase from the
Company that number of Default Shares that bears the same proportion of the
total number of Default Shares then being purchased as the number of Shares set
forth opposite the name of such Underwriter in Schedule I hereto bears to the
aggregate number of Shares set forth opposite the names of the non-defaulting
Underwriters, subject, however, to such adjustments to eliminate fractional
shares as the Representative in its sole discretion shall make.

            (b) In the event that the aggregate number of Default Shares exceeds
10% of the number of Shares, the Representative may in its discretion arrange
for itself or for another party or parties (including any non-defaulting
Underwriter or Underwriters who so agree) to purchase the Default Shares on the
terms contained herein. In the event that within five calendar days after such a
default the Representative does not arrange for the purchase of the Default
Shares as provided in this Section 9, this Agreement shall thereupon terminate,
without liability on the part of the Company with respect thereto (except in
each case as provided in Sections 5, 7, 8, 10 and 11(d)) or the Underwriters,
but nothing in this Agreement shall relieve a defaulting Underwriter or
Underwriters of its or their liability, if any, to the other Underwriters and
the Company for damages occasioned by its or their default hereunder.

            (c) In the event that any Default Shares are to be purchased by the
non-defaulting Underwriters, or are to be purchased by another party or parties
as aforesaid, the Representative or the Company shall have the right to postpone
the Closing Date, as the case may be for a period, not exceeding five business
days, in order to effect whatever changes may thereby be made necessary in the
Registration Statement or the Prospectus or in any other documents and
arrangements, and the Company agrees to file promptly any amendment or
supplement to the Registration Statement or the Prospectus which, in the opinion
of Underwriters' Counsel, may thereby be made necessary or advisable. The term
"Underwriter" as used in this Agreement shall include any party substituted
under this Section 9 with like effect as if it had originally been a party to
this Agreement with respect to such Shares.


                                       22



         10. Survival of Representations and Agreements. All representations and
warranties, covenants and agreements of the Underwriters and the Company
contained in this Agreement or in certificates of officers of the Company or any
Subsidiary submitted pursuant hereto, including the agreements contained in
Section 5, the indemnity agreements contained in Section 7 and the contribution
agreements contained in Section 8, shall remain operative and in full force and
effect regardless of any investigation made by or on behalf of any Underwriter
or any controlling person thereof or by or on behalf of the Company, any of its
officers and directors or any controlling person thereof, and shall survive
delivery of and payment for the Shares to and by the Underwriters. The
representations contained in Section 1 and the agreements contained in Sections
5, 7, 8, 10 and 111 hereof shall survive any termination of this Agreement,
including termination pursuant to Section 9 or 11 hereof.

         11. Effective Date of Agreement; Termination.

             (a) This Agreement shall become effective upon the execution of
this Agreement. Notwithstanding any termination of this Agreement, the
provisions of this Section 11 and of Sections 1, 5, 7, 8 and 12 through 17
inclusive, shall remain in full force and effect at all times after the
execution hereof.

             (b) The Representative shall have the right to terminate this
Agreement at any time prior to the Closing Date if (i) any domestic or
international event or act or occurrence has materially disrupted, or in the
opinion of the Representative will in the immediate future materially disrupt,
the market for the Company's securities or securities in general; or (ii)
trading on The New York Stock Exchange ("the NYSE") or The NASDAQ National
Market ("NASDAQ") shall have been suspended or been made subject to material
limitations, or minimum or maximum prices for trading shall have been fixed, or
maximum ranges for prices for securities shall have been required, on the NYSE
or NASDAQ or by order of the Commission or any other governmental authority
having jurisdiction; or (iii) a banking moratorium has been declared by any
state or federal authority or if any material disruption in commercial banking
or securities settlement or clearance services shall have occurred; (iv) any
downgrading shall have occurred in the Company's corporate credit rating or the
rating accorded the Company's debt securities by any "nationally recognized
statistical rating organization" as that term is defined by the Commission for
purposes of Rule 436(g)(2) under the Securities Act or if any such organization
shall have publicly announced that it has under surveillance or review, with
possible negative implications, its rating of any of the Company's debt
securities; or (v) if there has been since the time of the execution of this
Agreement or since the respective dates as of which information is given in the
Prospectus (excluding any supplement thereto), any Material Adverse Effect, or
(vi) (A) there shall have occurred any outbreak or escalation of hostilities or
acts of terrorism involving the United States or there is a declaration of a
national emergency or war by the United States or (B) there shall have been any
other calamity or crisis or any change in political, financial or economic
conditions if the effect of any such event in (A) or (B), in the judgment of the
Representative, makes it impracticable or inadvisable to proceed with the
offering, sale and delivery of the Shares, as the case maybe, on the terms and
in the manner contemplated by the Prospectus.

             (c) Any notice of termination pursuant to this Section 11 shall be
in writing.


                                       23



             (d) If this Agreement shall be terminated pursuant to any of the
provisions hereof (other than pursuant to (i) notification by the Representative
as provided in Section 10(b) hereof or (ii) Section 9(b) hereof), or if the sale
of the Shares provided for herein is not consummated because any condition to
the obligations of the Underwriters set forth herein is not satisfied or because
of any refusal, inability or failure on the part of the Company to perform any
agreement herein or comply with any provision hereof, the Company will, subject
to demand by the Representative, reimburse the Underwriters for all
out-of-pocket expenses (including the fees and expenses of their counsel),
incurred by the Underwriters in connection herewith.

         12. Notices. All communications hereunder, except as may be otherwise
specifically provided herein, shall be in writing, and:

            (a) if sent to any Underwriter, shall be mailed, delivered, or faxed
and confirmed in writing, to such Underwriter c/o Bear, Stearns & Co. Inc., 383
Madison Avenue, New York, New York 10179, Attention: Stephen Parish, Senior
Managing Director, Equity Capital Markets, with a copy to Underwriters' Counsel
at Morrison & Foerster LLP, 1290 Avenue of the Americas, New York, New York,
10104, Attention: James R. Tanenbaum, Esq.;

            (b) if sent to the Company, shall be mailed, delivered, or faxed and
confirmed in writing to the Company and its counsel at the addresses set forth
in the Registration Statement; provided, however, that any notice to an
Underwriter pursuant to Section 7 shall be delivered or sent by mail or
facsimile transmission to such Underwriter at its address set forth in its
acceptance facsimile to the Representative, which address will be supplied to
any other party hereto by the Representative upon request. Any such notices and
other communications shall take effect at the time of receipt thereof.

         13. Parties. This Agreement shall inure solely to the benefit of, and
shall be binding upon, the Underwriters, the Company and the controlling
persons, directors, officers, employees and agents referred to in Sections 7 and
8 hereof, and their respective successors and assigns, and no other person shall
have or be construed to have any legal or equitable right, remedy or claim under
or in respect of or by virtue of this Agreement or any provision herein
contained. This Agreement and all conditions and provisions hereof are intended
to be for the sole and exclusive benefit of the parties hereto and said
controlling persons and their respective successors, officers, directors, heirs
and legal representative, and it is not for the benefit of any other person,
firm or corporation. The term "successors and assigns" shall not include a
purchaser, in its capacity as such, of Shares from any of the Underwriters.

         14. Governing Law and Jurisdiction; Waiver of Jury Trial. This
Agreement shall be governed by and construed in accordance with the laws of the
State of New York. The Company irrevocably (a) submits to the jurisdiction of
any court of the State of New York or the United State District Court for the
Southern District of the State of New York for the purpose of any suit, action,
or other proceeding arising out of this Agreement, or any of the agreements or
transactions contemplated by this Agreement, the Registration Statement and the
Prospectus (each, a "Proceeding"), (b) agrees that all claims in respect of any
Proceeding may be heard and determined in any such court, (c) waives, to the
fullest extent permitted by law, any immunity from jurisdiction of any such
court or from any legal process therein, (d) agrees not to commence any
Proceeding other than in such courts, and (e) waives, to the fullest extent
permitted by law,


                                       24



any claim that such Proceeding is brought in an inconvenient forum. THE COMPANY
(ON BEHALF OF ITSELF AND, TO THE FULLEST EXTENT PERMITTED BYLAW, ON BEHALF OF
ITS RESPECTIVE EQUITY HOLDERS AND CREDITORS) HEREBY WAIVES ANY RIGHT IT MAY HAVE
TO A TRIAL BY JURY IN RESPECT OF ANY CLAIM BASED UPON, ARISING OUT OF OR IN
CONNECTION WITH THIS AGREEMENT AND THE TRANSACTIONS CONTEMPLATED BY THIS
AGREEMENT, THE REGISTRATION STATEMENT AND THE PROSPECTUS.

         15. Counterparts. This Agreement may be executed in any number of
counterparts, each of which shall be deemed to be an original, but all such
counterparts shall together constitute one and the same instrument. Delivery of
a signed counterpart of this Agreement by facsimile transmission shall
constitute valid and sufficient delivery thereof.

         16. Headings. The headings herein are inserted for convenience of
reference only and are not intended to be part of, or to affect the meaning or
interpretation of, this Agreement.

         17. Time is of the Essence. Time shall be of the essence of this
Agreement. As used herein, the term "business day" shall mean any day when the
Commission's office in Washington, D.C. is open for business.

                            [signature page follows]






                                       25



         If the foregoing correctly sets forth your understanding, please so
indicate in the space provided below for that purpose, whereupon this letter
shall constitute a binding agreement among us. Very truly yours,

                                            ALEXION PHARMACEUTICALS, INC.


                                            By: /s/ Leonard Bell
                                                --------------------------------
                                                Name:  Leonard Bell
                                                Title: Chief Executive Officer


         Accepted as of the date first above written

         BEAR, STEARNS & CO. INC.



         By: /s/ Stephen Parish
             ---------------------------------
             Name:  Stephen Parish
             Title:  Senior Managing Director






                                       26




                                   SCHEDULE I

Underwriter                                                         Shares
- -----------                                                         ------
Bear, Stearns & Co., Inc.                                        3,060,000
SG Cowen Securities Corporation                                    540,000
                                                                 =========

Total:                                                           3,600,000







                                    EXHIBIT A

                                  Subsidiaries

Alexion Antibody Technologies

Columbus Farming Corporation




                                     ANNEX I

                       Form of Opinion of Company Counsel

         1. Each of the Company and Columbus Farming Corporation ("CFC") has
been duly organized and validly exists as a corporation in good standing under
the laws of its jurisdiction of incorporation or organization, with full
corporate power and authority to own its properties and conduct its business as
described in the Registration Statement and the Prospectus.

         2. The Company has an authorized capitalization as set forth in the
Registration Statement and the Prospectus. All of the issued shares of capital
stock of the Company have been duly and validly authorized and issued, are fully
paid and non-assessable and were not issued in violation of or subject to any
preemptive or, to such counsel's knowledge, similar rights that entitle or will
entitle any person to acquire any shares from the Company upon issuance or sale
thereof. The Shares have been duly and validly authorized and, when delivered in
accordance with the Underwriting Agreement, will be duly and validly issued,
fully paid and non-assessable and will not have been issued in violation of or
subject to preemptive or, to the best of such counsel's knowledge, similar
rights that entitle or will entitle any person to acquire any Shares from the
Company upon issuance or sale thereof. To such counsel's knowledge, neither the
offering or nor the sale of the Shares as contemplated by the Underwriting
Agreement gives rise to any rights for or relating to the registration of any
shares of Common Stock or other securities of the Company, except those rights
which have been waived. All of the issued shares of capital stock of CFC have
been duly and validly authorized and issued and are fully paid and
non-assessable and are owned directly or indirectly by the Company, free and
clear of all Liens except as disclosed in the Registration Statement or the
Prospectus. The Common Stock and the Shares conform to the descriptions thereof
contained in the Registration Statement and the Prospectus.

         3. The Common Stock currently outstanding is included, and the Shares
are duly authorized for inclusion on the Nasdaq National Market.

         4. The Underwriting Agreement has been duly and validly authorized,
executed and delivered by the Company and constitutes the legal, valid and
binding obligation of the Company, enforceable in accordance with its terms,
except as enforceability may be limited by applicable bankruptcy, insolvency,
reorganization, moratorium or similar laws affecting creditors' rights generally
and except as enforceability may be subject to general principles of equity
(regardless of whether such enforceability is considered in a proceeding
inequity or at law).

         5. To such counsel's knowledge and other than as set forth in the
Prospectus, there are no judicial, regulatory or other legal or governmental
proceedings pending to which the Company or any of its Subsidiaries is a party
or of which any property of the Company or any of its Subsidiaries is the
subject which, if determined adversely to the Company or any of its
Subsidiaries, would individually or in the aggregate have a Material Adverse
Effect; and, to such counsel's knowledge, no such proceedings are threatened or
contemplated.


                                       1



         6. The execution, delivery, and performance of the Underwriting
Agreement and consummation of the transactions contemplated by Underwriting
Agreement do not and will not (A) conflict with or result in a breach of any of
the terms and provisions of, or constitute a default (or an event which with
notice or lapse of time, or both, would constitute a default) under, or result
in the creation or imposition of any lien, charge or encumbrance upon any
property or assets of the Company or any of its Subsidiaries pursuant to, any
indenture, mortgage, deed of trust, loan agreement or any other agreement or
instrument to which the Company or any of its Subsidiaries is a party or by
which any of the Company or any of its Subsidiaries or their respective
properties or assets may be bound and which is listed as an exhibit to the
Registration Statement and the documents incorporated therein by reference or
(B) violate or conflict with any provision of the certificate of incorporation
or by-laws of the Company or CFC, or, to the knowledge of such counsel, any
judgment, decree, order, statute, rule or regulation of any court or any
judicial, regulatory or other legal or governmental agency or body applicable to
the Company and CFC.

         7. No consent, approval, authorization, order, registration, filing,
qualification, license or permit of or with any court or any judicial,
regulatory or other legal or governmental agency or body is required for the
execution, delivery and performance of the Underwriting Agreement or
consummation of the transactions contemplated by the Underwriting Agreement,
except for (A) such as may be required under state securities or blue sky laws
in connection with the purchase and distribution of the Shares by the
Underwriters (as to which such counsel need express no opinion), (B) such as
have been made or obtained under the Securities Act and (C) such as are required
by the NASD.

         8. The Registration Statement and any amendments thereof and the
Prospectus and the supplements thereto (other than the financial statements and
schedules and other financial data included or incorporated by reference
therein, as to which no opinion need be rendered) comply as to form in all
material respects with the requirements of the Securities Act and the Rules and
Regulations. The documents filed under the Exchange Act and incorporated by
reference in the Registration Statement and the Prospectus or any amendment
thereof or supplement thereto (other than the financial statements and schedules
and other financial data included or incorporated by reference therein, as to
which no opinion need be rendered) when they were filed with the Commission,
complied as to form in all material respects with the Exchange Act and the Rules
and Regulations.

         9. The descriptions in the Registration Statement and in the
Prospectus, insofar as such statements constitute a summary of statutes, legal
matters, contracts, documents or proceedings referred to therein, fairly present
in all material respects the information required to be shown with respect to
such statutes, legal matters, contracts, documents and proceedings, and such
counsel does not know of any statutes or legal or governmental proceedings
required to be described in the Prospectus that are not described as required,
or of any contracts or documents of a character required to be described in the
Registration Statement or the Prospectus or included as exhibits to the
Registration Statement that are not described or included as required.

         10. The Company is not and, after giving effect to the offering and
sale of the Shares and the application of the proceeds thereof as described in
the Registration Statement and the


                                       2



Prospectus, will not be, an "investment company" as such term is defined in the
Investment Company Act of 1940, as amended.

         11. The Registration Statement is effective under the Securities Act,
and, to the knowledge of such counsel, no stop order suspending the
effectiveness of the Registration Statement or any post-effective amendment
thereof has been issued and no proceedings therefor have been initiated or
threatened by the Commission and all filings required by Rule 424(b) and Rule
430A under the Securities Act have been made.

         12. The Company has full right, power and authority to execute and
deliver the Underwriting Agreement and to perform its obligations thereunder,
and all corporate action required to be taken for the due and proper
authorization, execution and delivery of the Underwriting Agreement and the
Shares and consummation of the transactions contemplated by the Underwriting
Agreement, the Registration Statement and the Prospectus and as described in the
Registration Statement and the Prospectus have been duly and validly taken.

In addition, such opinion shall also contain a statement that such counsel has
participated in conferences with officers and representatives of the Company,
representatives of the independent public accountants for the Company and the
Underwriters at which the contents and the Prospectus and related matters were
discussed (and that such counsel has reviewed but did not take part in the
preparation of the documents incorporated by reference), and at which such
counsel inquired of the representatives of the Company as to the materiality of
the facts disclosed to such counsel and, although such counsel does not pass
upon, and does not assume any responsibility for, the accuracy, completeness or
fairness of any statement contained in the Registration Statement or the
Prospectus and such counsel has made no independent check or verification
thereof, based in part upon the foregoing (relying as to materiality to a large
extent upon the officers and representatives of the Company) no facts have come
to such counsel's attention that have led such counsel to believe that the
Registration Statement (except as to the financial statements and notes thereto
and other financial and statistical data included therein as to which such
counsel need not express any opinion or belief), as of the date of
effectiveness, contained an untrue statement of material fact or omitted to
state any material fact required to be stated therein or necessary in order to
make the statements therein not misleading or that the Prospectus (except as to
the financial statements and the notes thereto and other financial and
statistical data included therein or excluded therefrom as to which such counsel
need not express any opinion or belief), as of its date or as of the date of its
opinion, contained or contains an untrue statement of material fact or omitted
or omits to state a material fact necessary in order to make the statements
therein, in light of the circumstances under which they were made, not
misleading.


                                       3




                                    ANNEX II

                  Form of Intellectual Property Counsel Opinion

         1. Such counsel represents the Company in certain matters relating to
intellectual property, including patents, and is familiar with the technology
used by the Company in its business and the manner of its use and has read the
portions of the Registration Statement and the Prospectus that pertain such
technology and its use in its business by the Company and any risks relating
thereto (the "Patent Language");

         2. The Patent Language contain accurate descriptions of the Company's
Patents, Patent Applications and patents licensed to the Company and the
statements in the Patent Language therein insofar as such statements constitute
summaries of the legal matters, documents or proceedings referred to therein,
fairly present the information called for with respect to such legal matters,
documents and proceedings and fairly summarizes the matters referred to therein;

         3. such counsel has reviewed the Company's Patent Applications filed in
the United States and outside the United States and in the opinion of such
counsel, the Company's Patent Applications have been properly prepared and filed
on behalf of the Company, and are being diligently pursued by the Company; the
inventions described in the Company's Patent Applications are assigned or
licensed to the Company; to such counsel's knowledge, no other entity or
individual has any right or claim in any Company inventions or Company's Patent
Applications made solely by the Company, or any patent to be issued therefrom,
and in such counsel's opinion each of the Company's Patent Applications
discloses patentable subject matter; to such counsel's knowledge, there are no
legal or governmental proceedings pending (other than those relating to the
Patent Applications) relating to the Company, the claimed inventions of the
Company's Patents or the Company's Intellectual Property, and to such counsel's
knowledge, no such material proceedings are threatened or contemplated by
governmental authorities or others;

         4. such counsel has no knowledge of any facts which would preclude the
Company from having valid license rights or clear title to the Company's
Patents, and based on representations by the Company that no interests have been
conveyed to third parties which have not been recorded in the PTO, the Company
has clear record title to the Company's Patents free and clear of any liens or
encumbrances that have been recorded with the PTO;

         5. to the best of such counsel's knowledge, the Company has complied
with the PTO duty of candor and disclosure for each of the Company's patents,
and such counsel has no knowledge that the Company lacks or will be unable to
obtain any rights or licenses to use all Intellectual Property necessary for the
conduct of its business as now proposed to be conducted by the Company as
described in the Prospectus;

         6. except as disclosed in the Prospectus, such counsel has no knowledge
of any facts material to a determination of patentability regarding the
Company's Patent Applications not called to the attention of the PTO, and is
unaware of any facts not called to the attention of the PTO which would preclude
the grant of a patent for the Company's Patent Applications;


                                       1



         7. except as disclosed in the Prospectus, such counsel is not aware of
any basis for a finding of unenforceability or invalidity of any Company
Intellectual Property, and to the best of such counsel's knowledge, the Company
has not received any notice of infringement of or conflict with rights or claims
of others with respect to any Intellectual Property owned or used by the
Company;

         8. based on a review of the third party rights made known to counsel
and discussion with Company scientific personnel, (except as disclosed in the
Prospectus) such counsel has no knowledge of any patent rights of others which
are or would be infringed by specific products or processes referred to in the
Prospectus, which infringement, singly or in the aggregate, if the subject of an
unfavorable decision, ruling or finding, would result in any material adverse
effect on the condition, financial or otherwise, or in the earnings, business or
operations of the Company; and

         9. such counsel (A) has no reason to believe that the Patent Language
contained in the Registration Statement and the Prospectus included therein at
the time the Registration Statement became effective contained any untrue
statement of a material fact or omitted to state a material fact required to be
stated therein or necessary to make the statements therein not misleading and
(B) has no reason to believe that the Patent Language contained in the
Prospectus contains any untrue statement of a material fact or omits to state a
material fact necessary in order to make the statements therein, in light of the
circumstances under which they were made, not misleading.


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                                    ANNEX III

                            Form of Lock-Up Agreement

                                                              September __, 2003

Bear, Stearns & Co. Inc.
383 Madison Avenue
New York, New York 10179
Attention:  Equity Capital Markets

               Alexion Pharmaceuticals, Inc. Lock-Up Agreement

Ladies and Gentlemen:

         In consideration of the agreement of Bear, Stearns & Co. Inc., as
representative of the several underwriters listed on Schedule I attached thereto
(the "Representative") to purchase from Alexion Pharmaceuticals (the "Company")
up to _______ shares of common stock of the Company ("Common Stock"), as
contemplated by a Prospectus Supplement relating to the Common Stock (the
"Prospectus Supplement"), the undersigned hereby agrees that, for a period of 90
days after the date of the Prospectus Supplement (the "Lock-Up Period"), the
undersigned will not offer, sell, contract to sell, pledge or otherwise dispose
of, directly or indirectly, (a) any shares of Common Stock or any other capital
stock of the Company or (b) any other securities which are convertible into, or
exercisable or exchangeable for, Common Stock or other capital stock of the
Company, or publicly disclose the intention to make any such offer, sale, pledge
or disposition, in any such case without the prior written consent of the
Representative. Such agreement will not prevent (i) the exercise of options to
purchase shares of Common Stock pursuant to employee stock option plans existing
on the date of the Prospectus Supplement, (ii) as the exercise or conversion of
securities that are outstanding on the date of the Prospectus Supplement and
(iii) bona fide gifts of shares of Common Stock so long as the transferee of
such shares of Common Stock agrees with the Underwriters (as evidenced by a
signed letter to the Representative) not to sell or otherwise dispose of such
shares of Common Stock during the period of 90 days after the date of the
Prospectus Supplement.

         The undersigned hereby authorizes the Company during the Lock-Up Period
to cause any transfer agent for the Relevant Securities to decline to transfer,
and to note stop transfer restrictions on the stock register and other records
relating to, Relevant Securities for which the undersigned is the record holder
and, in the case of Relevant Securities for which the undersigned is the
beneficial but not the record holder, agrees during the Lock-Up Period to cause
the record holder to cause the relevant transfer agent to decline to transfer,
and to note stop transfer restrictions on the stock register and other records
relating to, such Relevant Securities. The undersigned hereby further agrees
that, without the prior written consent of the Representative, during the
Lock-up Period the undersigned (x) will not file or participate in the filing
with the Securities and Exchange Commission of any registration statement, or
circulate or participate in the circulation of any preliminary or final
prospectus or other disclosure document with respect to any proposed offering or
sale of a Relevant Security and (y) will not exercise any


                                       1



rights the undersigned may have to require registration with the Securities and
Exchange Commission of any proposed offering or sale of a Relevant Security.

         The undersigned hereby represents and warrants that the undersigned has
full power and authority to enter into this Agreement. Upon request, the
undersigned will execute any additional documents necessary in connection with
enforcement hereof. Any obligations of the undersigned shall be binding upon the
successors and assigns of the undersigned from the date first above written.

         This Agreement shall be governed by and construed in accordance with
the laws of the State of New York. Delivery of a signed copy of this letter by
facsimile transmission shall be effective as delivery of the original hereof.

                                            Very truly yours,

                                            By:
                                                --------------------------------

                                            Print Name:
                                                        ------------------------

                                       2

EX-99.1

                                                                    Exhibit 99.1

Alexion Pharmaceuticals Raises Approximately $44 Million in Sale of Common Stock

http://www.alexionpharm.com/http://www.alexionpharm.com/
- --------------------------------------------------------

    CHESHIRE, Conn., Sept. 12 /PRNewswire-FirstCall/ -- Alexion
Pharmaceuticals, Inc. (Nasdaq: ALXN) announced today a public offering of
                               ----
3.6 million shares of its common stock at $13 per share.  Subject to normal
closing conditions, Alexion will receive proceeds of approximately
$44 million, net of fees and other expenses related to the transaction.

    Alexion expects to use the net proceeds of the sale of the common stock to
fund working capital and other general corporate purposes, including
additional clinical trials of pexelizumab and eculizumab, as well as other
research and product development activities.  Bear, Stearns & Co. Inc. acted
as lead manager in the offering.

    Copies of the prospectus relating to the offering may be obtained from
Bear, Stearns & Co. Inc.

    The shelf registration statement relating to these securities has been
declared effective by the U.S. Securities and Exchange Commission. This press
release shall not constitute an offer to sell or the solicitation of an offer to
buy nor shall there be any sale of the securities in any state in which such
offer, solicitation or sale would be unlawful prior to registration or
qualification under the securities laws of any such state.

    Alexion is engaged in the discovery and development of therapeutic products
aimed at treating patients with a wide array of severe disease states, including
cardiovascular and autoimmune disorders, inflammation and cancer. Alexion's two
lead product candidates, pexelizumab and eculizumab, are currently undergoing
evaluation in several clinical development programs. Alexion is developing
pexelizumab, an antibody fragment, in collaboration with Procter & Gamble
Pharmaceuticals. Together the firms have completed a Phase III clinical study
with pexelizumab in coronary artery bypass graft surgery patients undergoing
cardiopulmonary bypass, and two large Phase II studies with pexelizumab in acute
myocardial infarction patients. In addition, eculizumab is currently in Phase II
clinical trials in rheumatoid arthritis and membranous nephritis, and has been
evaluated in pilot programs for the treatment of paroxysmal nocturnal
hemoglobinuria and dermatomyositis. Alexion is engaged in discovering and
developing a pipeline of additional antibody therapeutics targeting severe unmet
medical needs, through its wholly owned subsidiary, Alexion Antibody
Technologies, Inc. This press release and further information about Alexion
Pharmaceuticals, Inc. can be found on the World Wide Web at:
http://www.alexionpharm.com.
- ----------------------------

    This news release contains forward-looking statements. Such statements are
subject to factors that may cause Alexion's results and plans to differ from
those expected, including the results of pre-clinical or clinical studies


                                       1



(including termination or delay in clinical programs), the need for additional
research and testing, delays in arranging satisfactory manufacturing capability,
inability to acquire funding on timely and satisfactory terms, delays in
developing or adverse changes in commercial relationships, the possibility that
results of earlier clinical trials are not predictive of safety and efficacy
results in later clinical trials, dependence on Procter & Gamble Pharmaceuticals
for development and commercialization of pexelizumab, the risk that third
parties won't agree to license any necessary intellectual property to us on
reasonable terms, and a variety of other risks set forth from time to time in
Alexion's filings with the Securities and Exchange Commission, including but not
limited to the risks discussed in Alexion's Annual Report on Form 10-K for the
year ended July 31, 2002 and Quarterly Report on Form 10-Q for the quarter ended
October 31, 2002. Alexion does not intend to update any of these forward-looking
statements to reflect events or circumstances after the date hereof, except when
a duty arises under law.

     Contacts:

     Alexion Pharmaceuticals, Inc.        Euro RSCG Life NRP
     Leonard Bell, M.D.                   Ernie Knewitz (Media)
     Chief Executive Officer              (212) 845-4253
     (203) 272-2596

     Rx Communications

     Rhonda Chiger (Investor)

     (917) 322-2569

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