ALEXION PHARMACEUTICALS INC
S-3, 2000-10-06
PHARMACEUTICAL PREPARATIONS
Previous: ALEXION PHARMACEUTICALS INC, 10-K, EX-99.1, 2000-10-06
Next: ALEXION PHARMACEUTICALS INC, S-3, EX-12.1, 2000-10-06



<PAGE>
    AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 6, 2000

                                                      REGISTRATION NO. 333-
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                         WASHINGTON, D.C. 20549
                             ---------------------
                                    FORM S-3
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                             ---------------------
                         ALEXION PHARMACEUTICALS, INC.
             (Exact Name of Registrant as Specified in Its Charter)

<TABLE>
<S>                                                       <C>
                        DELAWARE                                                 13-3648318
    (State or Other Jurisdiction of Incorporation or              (I.R.S. Employer Identification Number)
                     Organization)
</TABLE>

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

                                25 SCIENCE PARK
                              NEW HAVEN, CT 06511
                                 (203) 776-1790
  (Address, Including Zip Code, and Telephone Number, Including Area Code, of
                   Registrant's Principal Executive Offices)
                         ------------------------------

                               LEONARD BELL, M.D.
                         ALEXION PHARMACEUTICALS, INC.
                                25 SCIENCE PARK
                              NEW HAVEN, CT 06511
                                 (203) 776-1790
 (Name, Address, Including Zip Code, and Telephone Number, Including Area Code,
                             of Agent for Service)
                         ------------------------------

Copies of all communications, including all communications sent to the agent for
                          service, should be sent to:
                            MERRILL M. KRAINES, ESQ.
                           LAWRENCE A. SPECTOR, ESQ.
                          FULBRIGHT & JAWORSKI L.L.P.
                                666 FIFTH AVENUE
                            NEW YORK, NEW YORK 10103
                         ------------------------------

    APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: From time
to time after the effective date of this Registration Statement. If the only
securities being registered on this Form are being offered pursuant to dividend
or interest reinvestment plan, please check the following box: / /

    If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, as amended, other than securities offered only in connection with dividend
or interest reinvestment plans, check the following box. /X/

    If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. / /

    If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. / /

    If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box. /X/

                        CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
                                                                                   PROPOSED MAXIMUM
         TITLE OF EACH CLASS               AMOUNT TO BE       PROPOSED MAXIMUM         AGGREGATE            AMOUNT OF
            OF SECURITIES                   REGISTERED         PRICE PER UNIT     OFFERING PRICE (A)    REGISTRATION FEE
<S>                                     <C>                  <C>                  <C>                  <C>
Common Stock, $.0001 par value per         $300,000,000             100%             $300,000,000            $79,200
  share
Debt Securities(b)
Warrants(b)
</TABLE>

(a) Estimated solely for purposes of calculating the registration fee pursuant
    to Rule 457(o).

(b) In addition to any Debt Securities or Warrants that may be issued directly
    under this Registration Statement, there are being registered hereunder an
    indeterminate number of shares of Common Stock as may be issued upon
    conversion or exchange of the Debt Securities or conversion of the Warrants,
    as the case may be. No separate consideration will be received for any
    shares of Common Stock so issued upon conversion or exchange.
                         ------------------------------

    The registrant hereby amends this registration statement on such date or
dates as may be necessary to delay its effective date until the registrant shall
file a further amendment which specifically states that this registration
statement shall thereafter become effective in accordance with Section 8(a) of
the Securities Act of 1933 or until the registration statement shall become
effective on such date as the Commission, acting pursuant to said Section 8(a),
may determine.

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
<PAGE>
THE INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. WE MAY
NOT SELL THESE SECURITIES UNTIL THE SECURITIES AND EXCHANGE COMMISSION DECLARES
OUR REGISTRATION STATEMENT EFFECTIVE. THIS PROSPECTUS IS NOT AN OFFER TO SELL
THESE SECURITIES AND IS NOT SOLICITING AN OFFER TO BY THESE SECURITIES IN ANY
STATE WHERE THE OFFER OR SALE IS NOT PERMITTED.
<PAGE>
                  SUBJECT TO COMPLETION, DATED OCTOBER 6, 2000

$300,000,000

                                                                          [LOGO]

DEBT SECURITIES
COMMON STOCK
WARRANTS
----------------------------------------------------------------------

<TABLE>
<S>                                            <C>
- ALEXION PHARMACEUTICALS, INC. IS OFFERING    - CLOSING PRICE OF OUR COMMON STOCK ON
  SECURITIES UP TO AN AGGREGATE OF               OCTOBER 5, 2000: $104.5625 PER SHARE
  $300,000,000

- TRADING SYMBOL: NASDAQ NATIONAL MARKET --
  ALXN
</TABLE>

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

This prospectus will allow us to issue securities over time. This means:

    - we will provide a prospectus supplement each time we issue securities;

    - the prospectus supplement will inform you about the specific terms of that
      offering and may also add, update or change information contained in this
      document;

    - you should read this document and any prospectus supplement carefully
      before you invest; and

    - we may sell the securities through underwriters, through dealers, directly
      to one or more institutional purchasers or through agents.

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

THE SECURITIES AND EXCHANGE COMMISSION AND STATE SECURITIES REGULATORS HAVE NOT
APPROVED OR DISAPPROVED OF THESE SECURITIES, OR DETERMINED IF THIS PROSPECTUS
   IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO
                                  THE CONTRARY IS A CRIMINAL OFFENSE.

           INVESTING IN THESE SECURITIES INVOLVES A HIGH DEGREE OF RISK.

                    SEE "RISK FACTORS" BEGINNING ON PAGE 4.

                  The date of this prospectus is October   , 2000.
<PAGE>
                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                PAGE
                                                              --------
<S>                                                           <C>
Summary.....................................................      1
  BUSINESS OF ALEXION.......................................      1
  RECENT DEVELOPMENTS.......................................      2
  THE SECURITIES WE MAY OFFER...............................      2
  RATIO OF EARNINGS TO FIXED CHARGES........................      3
Risk Factors................................................      4
Special Note Regarding Forward-Looking Statements...........     11
Use of Proceeds.............................................     11
Description of Debt Securities..............................     12
Description of Common Stock.................................     13
Description of Warrants.....................................     13
Plan of Distribution........................................     15
Legal Matters...............................................     15
Experts.....................................................     16
Where You Can Find More Information.........................     16
</TABLE>

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

    YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS PROSPECTUS AND THE
DOCUMENTS INCORPORATED BY REFERENCE. WE HAVE NOT AUTHORIZED ANYONE TO PROVIDE
YOU WITH INFORMATION DIFFERENT FROM THAT CONTAINED IN THIS PROSPECTUS. THE
INFORMATION CONTAINED IN THIS PROSPECTUS IS ACCURATE ONLY AS OF THE DATE OF THIS
PROSPECTUS, REGARDLESS OF THE TIME OF DELIVERY OF THIS PROSPECTUS OR OF ANY SALE
OF NOTES OR COMMON STOCK. OUR BUSINESS, FINANCIAL CONDITION, RESULTS OF
OPERATIONS AND PROSPECTS MAY CHANGE AFTER THAT DATE.

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

                                       i
<PAGE>
                                    SUMMARY

    THIS SUMMARY PROVIDES AN OVERVIEW OF SELECTED INFORMATION AND DOES NOT
CONTAIN ALL THE INFORMATION YOU SHOULD CONSIDER. YOU SHOULD READ THE ENTIRE
PROSPECTUS, INCLUDING THE SECTION ENTITLED "RISK FACTORS," CAREFULLY BEFORE
MAKING AN INVESTMENT DECISION.

BUSINESS OF ALEXION

    We are a biopharmaceutical company developing treatments for diseases in
humans. Our program for developing genetically altered antibodies for the
treatment of disease is our most extensive and advanced product development
program.

    Antibodies are proteins that bind to specific targets and are used by the
immune system to protect the body. We have proprietary rights to genetically
altered antibodies that can potentially be used in treatments for heart disease,
diseases of the immune system, inflammation and cancer. In September 2000, we
augmented our antibody product development program through the acquisition of
Prolifaron, Inc. Prolifaron was a biopharmaceutical company with rights to a
portfolio of potential antibody product candidates and with know-how and
proprietary technology for developing antibodies.

    Two of our antibody product candidates are undergoing clinical trials that
test for safety, dosing and effectiveness in humans. These antibodies target
specific diseases that arise when the human immune system induces undesired
inflammation. These antibodies are designed to block the components of the human
immune system that cause the undesired inflammation while allowing beneficial
components of the immune system to remain functional. The specific component of
the human immune system which these two product candidates are designed to block
is called "complement."

    We call one of the antibodies in clinical trials 5G1.1-SC. 5G1.1-SC is being
tested for the treatment of acute inflammation in the human body caused by the
trauma of heart and lung bypass procedures during open heart surgery in
Phase IIb clinical trials, and caused by heart attacks in Phase II clinical
clinical trials. We call the second antibody product candidate in clinical
trials 5G1.1. 5G1.1 is in Phase II trials for the treatment of rheumatoid
arthritis, a chronic autoimmune disease, and membranous nephritis, a kidney
disease. We are also testing 5G.1.1 in Phase Ib clinical trials in patients for
the treatment of psoriasis, a skin disorder, dermatomyositis, a muscle disorder,
and pemphigoid, a severe inflammatory skin disorder.

    We have retained all of our rights to 5G1.1. We have a collaboration
agreement with Procter & Gamble Pharmaceuticals with respect to the development
and commercialization of 5G1.1-SC. The initial subject of the collaboration is
to study the use of 5G1.1-SC for the treatment of inflammation caused by heart
and lung bypass procedures during open heart surgery, heart attacks and
angioplasty procedures for un-blocking clogged arteries.

    In addition to our program for developing products that inhibit the
inflammatory effects of complement and our technology programs focusing on human
antibody discovery and development, we are developing another type of
anti-inflammatory drug known as Apogens. Apogens are designed to block
disease-causing T-cells, another component of the human immune system. We are
currently completing preclinical studies of our first Apogen, targeting the
treatment of patients with multiple sclerosis.

    We are also developing methods of blocking the human immune system to permit
the use of cells and organs from non-human species in the treatment of diseases
in humans. This product development program is initially targeting the treatment
of patients with Parkinson's disease and patients with spinal cord injury with
genetically altered pig cells.

    We were incorporated in Delaware in January 1992. Our principal executive
offices are located at 25 Science Park, New Haven, Connecticut 06511, and our
telephone number is (203) 776-1790.

                                       1
<PAGE>
RECENT DEVELOPMENTS

CLINICAL STUDIES

    In August 2000, we announced that we had completed enrollment in a Phase II
clinical trial testing the safety and efficacy of 5G1.1 in approximately 200
patients with rheumatoid arthritis. We expect that these patients will receive
treatment with either 5G1.1 or placebo for a three month period. Additionally,
in August 2000 we also announced that we had commenced enrollment in an
open-label trial of 5G1.1 in rheumatoid arthritis patients which is designed to
test safety over a twelve month treatment period.

    In September 2000, we announced that we had completed enrollment in a Phase
IIb clinical trial testing the safety and efficacy of 5G1.1-SC in approximately
1,000 patients undergoing heart and lung bypass procedures during open heart
surgery. In September 2000, we also announced that the FDA designated 5G1.1-SC
for the treatment of patients undergoing heart and lung bypass procedures during
open heart surgery as a "fast track" product eligible for expedited development
and FDA review.

    In October 2000, we announced that the FDA granted Orphan Drug status to
5G1.1 for the treatment of patients with dermatomyositis, a severe inflammatory
muscle disorder. We are currently enrolling patients in a Phase Ib pilot
clinical trial that is designed to gather data regarding the safety and
biological and clinical effects of 5G1.1 in this patient population. The Orphan
Drug designation provides us with market exclusivity for seven years from the
drug's approval date.

PROLIFARON ACQUISITION

    On September 22, 2000, we acquired Prolifaron, a privately-held
biopharmaceutical company located in San Diego, California. Prolifaron was
developing therapeutic antibodies addressing multiple diseases, including
cancer.

    The acquisition was in the form of a merger between our new wholly owned
subsidiary, Alexion Antibody Technologies, Inc., and Prolifaron. In the merger,
we are obligated to issue up to issued 400,000 shares of our common stock, with
a value of approximately $41 million, to the stockholders of Prolifaron. We
agreed to register the possible resale of those shares of common stock by the
Prolifaron stockholders. We are required to file a registration statement with
the SEC covering the resale of 200,000 shares within 15 days after the
publication of consolidated financial statements for our fiscal quarter ending
October 31, 2000. We are required to file a registration statement with the SEC
covering the resale of the remaining 200,000 shares on or before April 30, 2001.

THE SECURITIES WE MAY OFFER

    This prospectus is part of a registration statement (No. 333-   ) that we
filed with the SEC utilizing a "shelf" registration process. Under this shelf
process, we may offer from time to time up to $300,000,000.00 of any of the
following securities, either separately or in units: Debt Securities, Common
Stock and Warrants. This prospectus provides you with a general description of
the securities we may offer. Each time we offer securities, we will provide you
with a prospectus supplement that will describe the specific amounts, prices and
terms of the securities being offered. The prospectus supplement may also add,
update or change information contained in this prospectus.

DEBT SECURITIES

    We may offer unsecured general obligations of our company, which may be
senior or subordinate. The senior debt securities and the subordinated debt
securities are together referred to in this prospectus as the "debt securities."

                                       2
<PAGE>
    Any debt securities offered will be issued under an indenture between us and
a trustee which we will name in the prospectus supplement. If we offer and sell
any debt securities, we will file the indenture as a post-effective amendment to
the registration statement of which this prospectus is a part and the indenture
will be described in the prospectus supplement.

COMMON STOCK

    We may issue our common stock, par value $0.0001 per share.

WARRANTS

    We may issue warrants for the purchase of debt securities or common stock.
We may issue warrants independently or together with other securities.

RATIO OF EARNINGS TO FIXED CHARGES

    Our deficiency in earnings to cover fixed charges for each of the periods
indicated is as follows (in thousands):

<TABLE>
<CAPTION>
                                                       YEAR ENDED JULY 31,
                                                       -------------------
                                         2000       1999       1998       1997       1996
                                       --------   --------   --------   --------   --------
<S>                                    <C>        <C>        <C>        <C>        <C>
                                       $(20,280)  $(6,426)   $(7,893)   $(7,278)   $(5,459)
</TABLE>

    The ratio of earnings to fixed charges is computed by dividing (a) income
before interest expense, income taxes and other fixed charges by (b) fixed
charges including interest expense, amortization of debt issuance costs and the
portion of rent expense which represents interest. For each of the periods
indicated above, earnings were insufficient to cover fixed charges by the
amounts noted above. The deficiency in earnings to cover fixed charges is
computed by adding net loss to the portion of rent expense which represents
interest for all periods presented.

                                       3
<PAGE>
                                  RISK FACTORS

    YOU SHOULD CAREFULLY CONSIDER THE FOLLOWING RISK FACTORS BEFORE YOU DECIDE
TO INVEST IN THE SECURITIES. YOU SHOULD ALSO CONSIDER THE OTHER INFORMATION IN
THIS PROSPECTUS AND INFORMATION INCORPORATED BY REFERENCE IN THIS PROSPECTUS.
THE RISKS AND UNCERTAINTIES BELOW ARE NOT THE ONLY ONES FACING ALEXION BECAUSE
WE ARE ALSO SUBJECT TO ADDITIONAL RISKS AND UNCERTAINTIES NOT PRESENTLY KNOWN TO
US. IF ANY OF THESE RISKS ACTUALLY OCCURS, OUR BUSINESS, FINANCIAL CONDITION,
OPERATING RESULTS OR CASH FLOWS COULD BE HARMED.

    IF WE CONTINUE TO INCUR OPERATING LOSSES, WE MAY BE UNABLE TO CONTINUE OUR
OPERATIONS.

    We have incurred losses since we started our company in January 1992. As of
July 31, 2000, we had an accumulated deficit of approximately $67.2 million. If
we continue to incur operating losses and fail to become a profitable company,
we may be unable to continue our operations. Since we began our business, we
have focused on research and development of product candidates. We have no
products that are available for sale. We expect to continue to operate at a net
loss for at least the next several years as we continue our research and
development efforts, continue to conduct clinical trials and develop
manufacturing, sales, marketing and distribution capabilities. Our future
profitability depends on our receiving regulatory approval of our product
candidates and our ability to successfully manufacture and market approved
drugs. The extent of our future losses and the timing of our profitability are
highly uncertain.

    IF WE DO NOT OBTAIN REGULATORY APPROVAL FOR OUR DRUG PRODUCTS WE WILL NOT BE
ABLE TO SELL OUR DRUG PRODUCTS.

    We cannot sell or market our drugs without regulatory approval. If we cannot
obtain regulatory approval for our products, the value of our company and our
results of operations will be harmed. In the United States, we must obtain
approval from the U.S. Food and Drug Administration, or FDA, for each drug that
we intend to sell. Obtaining FDA approval is typically a lengthy and expensive
process, and approval is highly uncertain. Foreign governments also regulate
drugs distributed outside the United States. None of our product candidates has
received regulatory approval to be marketed and sold in the United States or any
other country. We do not anticipate receiving regulatory approval of any of our
product candidates for at least the next several years.

    IF OUR DRUG TRIALS ARE DELAYED OR ACHIEVE UNFAVORABLE RESULTS, WE WILL NOT
BE ABLE TO OBTAIN REGULATORY APPROVAL FOR OUR PRODUCTS.

    We must conduct extensive testing of our product candidates before we can
obtain regulatory approval for our products. We need to conduct both preclinical
animal testing and clinical human trials. These tests and trials may not achieve
favorable results. We would need to reevaluate any drug that did not test
favorably and either alter the drug or the dose, or abandon the drug development
project. As a result, we would not be able to obtain regulatory approval on a
timely basis, if ever.

    There are other reasons why drug testing could be delayed. For human trials,
patients must be recruited and each product candidate must be tested for each
clinical indication, at various doses and formulations. Also to ensure safety
and effectiveness, the effect of drugs often must be studied over a long period
of time, especially for the chronic diseases that we are studying. Unfavorable
results or insufficient patient enrollment in our clinical trials could delay or
cause us to abandon a product development program.

    Additional factors that can cause delay or termination of our clinical
trials include:

    - slow patient enrollment;

    - long treatment time required to demonstrate effectiveness;

    - lack of sufficient supplies of the product candidate;

                                       4
<PAGE>
    - adverse medical events or side effects in treated patients;

    - lack of effectiveness of the product candidate being tested; and

    - lack of sufficient funds.

    IF WE FAIL TO OBTAIN THE CAPITAL NECESSARY TO FUND OUR OPERATIONS, WE WILL
BE UNABLE TO CONTINUE OR COMPLETE OUR PRODUCT DEVELOPMENT.

    In the future, we will need to raise substantial additional capital to fund
operations and complete our product development. We may not get funding when we
need it or on favorable terms. If we cannot raise adequate funds to satisfy our
capital requirements, we may have to delay, scale-back or eliminate our research
and development activities or future operations. We might have to license our
technology to others. This could result in sharing revenues which we might
otherwise retain for ourselves. Any of these actions may harm our business.

    The amount of capital we may need depends on many factors, including:

    - the progress, timing and scope of our research and development programs;

    - the progress, timing and scope of our preclinical studies and clinical
      trials;

    - the time and cost necessary to obtain regulatory approvals;

    - the time and cost necessary to further develop manufacturing processes,
      arrange for contract manufacturing or build manufacturing facilities and
      obtain the necessary regulatory approvals for those facilities;

    - the time and cost necessary to develop sales, marketing and distribution
      capabilities; and

    - any new collaborative, licensing and other commercial relationships that
      we may establish.

    IF OUR COLLABORATION WITH PROCTER & GAMBLE IS TERMINATED, WE MAY BE UNABLE
TO COMMERCIALIZE 5G1.1-SC IN THE TIME EXPECTED, IF AT ALL, AND OUR BUSINESS
WOULD BE HARMED.

    We rely exclusively on Procter & Gamble to provide funding and additional
resources for the development and commercialization of 5G1.1-SC. These include
funds and resources for:

    - clinical development and manufacturing;

    - obtaining regulatory approvals; and

    - sales, marketing and distribution efforts worldwide.

    We cannot guarantee that Procter & Gamble will devote the resources
necessary to successfully develop and commercialize 5G1.1-SC. Either party may
terminate our collaboration agreement for specified reasons, including a
material breach or the occurrence of a change of control.

    Termination of our agreement with Procter & Gamble would cause significant
delays in the development of 5G1.1-SC and result in additional development
costs. We would need to fund the development and commercialization of 5G1.1-SC
on our own or identify a new development partner. We might also have to repeat
testing already completed with Procter & Gamble.

    IF WE ARE UNABLE TO ENGAGE AND RETAIN THIRD-PARTY COLLABORATORS, OUR
RESEARCH AND DEVELOPMENT EFFORTS MAY BE DELAYED.

    We depend upon third-party collaborators to assist us in the development of
our product candidates. If any of our existing collaborators breaches or
terminates its agreement with us or does not perform its development work under
the agreement, we would experience significant delays in the development or
commercialization of our product candidates. We would also experience
significant

                                       5
<PAGE>
delays if we cannot engage additional collaborators when required. In either
event, we would be required to devote additional funds or other resources to
these activities or to terminate them.

    We cannot assure you that:

    - we will be able to negotiate acceptable collaborative agreements to
      develop or commercialize our products;

    - any arrangements with third parties will be successful; or

    - current or potential collaborators will not pursue treatments for other
      diseases or seek other ways of developing treatments for our disease
      targets.

    IF WE CANNOT PROTECT THE CONFIDENTIALITY AND PROPRIETARY NATURE OF OUR TRADE
SECRETS, OUR BUSINESS AND COMPETITIVE POSITION WILL BE HARMED.

    Our business requires using sensitive technology, techniques and proprietary
compounds which we protect as trade secrets. However, since we are a small
company, we also rely heavily on collaboration with suppliers, outside
scientists and other drug companies. Collaboration presents a strong risk of
exposing our trade secrets. If our trade secrets were exposed, it would help our
competitors and adversely affect our business prospects.

    In order to more effectively protect our drugs and technology, we need to
obtain patents covering the drugs and technologies we develop. Our drugs are
expensive and time-consuming to test and develop. Without patent protection,
competitors may copy our methods, or the chemical structure or other aspects of
our drug. Even if we obtain patents, the patents may not be broad enough to
protect our drugs from copy-cat products.

    IF WE ARE FOUND TO BE INFRINGING ON PATENTS OWNED BY OTHERS, WE MAY BE
FORCED TO OBTAIN A LICENSE TO CONTINUE THE SALE OR DEVELOPMENT OF OUR DRUGS AND
PAY DAMAGES.

    Parts of our technology, techniques and proprietary compounds and potential
drug candidates may conflict with patents owned by or granted to others. If we
cannot resolve these conflicts, we may be liable for damages or be required to
obtain costly licenses. For example, we are aware of broad patents owned by
others relating to the manufacture, use and sale of recombinant humanized
antibodies, recombinant humanized single chain antibodies, recombinant human
antibodies, recombinant human single chain antibodies, and genetically
engineered animals. Many of our products are genetically engineered antibodies,
including recombinant humanized antibodies, recombinant humanized single chain
antibodies, recombinant human antibodies, recombinant human single chain
antibodies, and other products are tissues from animals.

    We have received notices from the owners of some of these patents claiming
that their patents may be relevant to the development of some of our drug
candidates. In response to some of these notices, we have obtained licenses.
However, with regard to other patents, we have either determined in our judgment
that:

    - our products do not infringe the patents;

    - we do not believe the patents are valid; or

    - we have identified and are testing various modifications which we believe
      should not infringe the patents and which should permit commercialization
      of our product candidates.

    Any patent holders could sue us for damages and seek to prevent us from
selling or developing our drugs. Legal disputes can be costly and time consuming
to defend. If any of these actions are successful, we could be required to pay
damages or to obtain a license to sell or develop our drugs. A required license
may not be available on acceptable terms, if at all.

                                       6
<PAGE>
    IF THE TESTING OR USE OF OUR PRODUCTS HARMS PEOPLE, WE COULD BE SUBJECT TO
COSTLY AND DAMAGING PRODUCT LIABILITY CLAIMS.

    The testing, manufacturing, marketing and sale of drugs for use in humans
exposes us to product liability risks. Side effects and other problems from
using our products could give rise to product liability claims against us. We
might have to recall our products, if any, from the marketplace. Some of these
risks are unknown at this time. For example, little is known about the potential
long-term health risks of transplanting pig tissue into humans, a goal of our
UniGraft product development program.

    In addition, we may be sued by people who participate in our clinical
trials. A number of patients who participate in such trials are already
critically ill when they enter a study. Any waivers we may obtain from people
who sign up for our trials may not protect us from liability or litigation. Our
product liability insurance may not cover all potential liabilities. Moreover,
we may not be able to maintain our insurance on acceptable terms. As a result of
these factors, a product liability claim, even if successfully defended, could
have a material adverse effect on our business, financial condition and results
of operations.

    IF WE CANNOT MANUFACTURE OUR DRUG CANDIDATES IN SUFFICIENT AMOUNTS AT
ACCEPTABLE COSTS AND ON A TIMELY BASIS, WE MAY BE UNABLE TO MEET THE NEED FOR
MATERIALS FOR PRODUCT TESTING AND LATER, FOR POTENTIAL SALE IN THE MARKET.
EITHER EVENT WOULD HARM OUR BUSINESS.

    For our drug trials, we need to produce sufficient amounts of product for
testing. We do not have the capacity to produce more than one product candidate
at a time. In addition, our small manufacturing plant cannot manufacture enough
of our product candidates for later stage clinical development. We depend on a
few outside suppliers for manufacturing. If we experience interruptions in the
manufacture of our products for testing, our drug development efforts will be
delayed. If any of our outside manufacturers stops manufacturing our products or
reduces the amount manufactured, we will need to find other alternatives. If we
are unable to find an acceptable outside manufacturer on reasonable terms, we
will have to divert our own resources to manufacturing. As a result, our ability
to conduct testing would be materially adversely affected. Submission of
products and new development programs for regulatory approval would be delayed.
Our competitive position and our prospects for achieving profitability could be
materially and adversely affected.

    We have no experience or capacity for manufacturing drug products in volumes
that will be necessary to support commercial sales. If we are unable to
establish and maintain commercial scale manufacturing within our planned time
and cost parameters, sales of our products and our financial performance will be
adversely affected.

    We may encounter problems in any of the following areas as we attempt to
increase the scale, process or size of manufacturing:

    - design, construction and qualification of manufacturing facilities that
      meet regulatory requirements;

    - production yields from the manufacturing process;

    - purity of our drug products;

    - quality control and assurance;

    - shortages of qualified personnel; and

    - compliance with FDA regulations.

                                       7
<PAGE>
    IF OUR BUSINESS AND PRODUCTS, EVEN AFTER REGULATORY APPROVAL IS OBTAINED,
FAIL TO COMPLY WITH REGULATORY REQUIREMENTS, OUR ABILITY TO SELL PRODUCTS AND
CONDUCT BUSINESS WILL BE HARMED.

    Even if we receive regulatory approval for any product, our business will
always be subject to substantial regulation by the FDA or a comparable foreign
regulatory agency. The discovery of previously unknown problems with a product
or its manufacture may result in restrictions on the product or manufacturer,
including withdrawal of the product from the market. The consequences for
failure to comply with applicable regulatory requirements can be serious,
resulting in:

    - warning letters;

    - fines and other civil penalties;

    - suspended regulatory approvals;

    - refusal to approve pending applications or supplements to approved
      applications;

    - refusal to permit exports from the United States;

    - product recalls;

    - seizure of products;

    - injunctions;

    - operating restrictions;

    - total or partial suspension of production; and/or

    - criminal prosecutions.

    Any of these consequences could result in withdrawal of approval, or require
reformulation of the drug, additional preclinical testing or clinical trials,
changes in labeling of the product, and/or additional marketing applications. We
would be required to expend time and resources in correcting the problem,
including any adverse publicity associated with the problem, in order to put the
product back on the market. These delays and uses of resources would hurt our
business, profitability and reputation.

    IF WE ARE UNABLE TO ESTABLISH SALES, MARKETING AND DISTRIBUTION
CAPABILITIES, OR TO ENTER INTO AGREEMENTS WITH THIRD PARTIES TO DO SO, WE WILL
BE UNABLE TO SUCCESSFULLY MARKET AND SELL FUTURE DRUG PRODUCTS.

    We have no sales, marketing or distribution personnel or capabilities. If we
are unable to establish those capabilities, either by developing our own
capabilities or entering into agreements with others, we will not be able to
successfully sell our products. In that event, we will not be able to generate
significant revenues. We cannot guarantee that we will be able to hire the
qualified sales and marketing personnel we need. We may not be able to enter
into any marketing or distribution agreements on acceptable terms, if at all. We
are relying on Procter & Gamble for sales, marketing and distribution, of
5G.1-SC. Procter & Gamble, or any future collaborators, may not succeed at
selling any of our future drug products.

    IF WE ARE UNABLE TO OBTAIN REIMBURSEMENT FROM GOVERNMENT HEALTH
ADMINISTRATION AUTHORITIES, PRIVATE HEALTH INSURERS AND OTHER ORGANIZATIONS FOR
OUR FUTURE PRODUCTS, OUR PRODUCTS MAY BE TOO COSTLY FOR REGULAR USE AND OUR
ABILITY TO GENERATE REVENUES WOULD BE HARMED.

    Our future revenues and profitability will be affected by the continuing
efforts of governmental and private third-party payors to contain or reduce the
costs of health care through various means. If these entities refuse to provide
reimbursement with respect to our products or determine to provide a low level
of reimbursement, our products may be too costly for general use. Any limitation
on the use of our products will have a material adverse effect on our ability to
generate revenues and achieve profitability. We expect a number of federal,
state and foreign proposals to control the cost of drugs

                                       8
<PAGE>
through government regulation. We are unsure of the form that any health care
reform legislation may take or what actions any of these authorities and private
payors may take in response to the proposed reforms. Therefore, we cannot
precisely predict the effect of any reform on our business.

    EVEN IF WE SUCCESSFULLY DEVELOP OUR PRODUCTS FOR TRANSPLANTING ANIMAL CELLS
INTO HUMANS, THIS TECHNOLOGY MAY NOT BE ACCEPTED BY THE MARKET DUE TO MEDICAL
CONCERNS OR UNANTICIPATED REGULATION.

    Our program for the development of animal cells for transplantation into
humans may never result in any therapeutic products. This technology is subject
to extensive clinical testing and we are not aware of any such technology that
has been approved for sale by the FDA or comparable foreign regulatory
authorities. Even if we succeed in developing these products, our products may
not be widely accepted by the medical community or third-party payors until more
facts are established and ethical consensus is reached regarding the use of
animal cells. In addition, concerns relating to the risk of introducing new
animal viruses to infect the human species through the transplantation process
may also create additional regulatory hurdles for FDA approval. If accepted, the
degree of acceptance may limit the size of the market for our products.
Moreover, due to the controversial nature of transplantation of animal cells
into humans generally, market prices for our securities may be subject to
increased volatility.

    IF OUR COMPETITORS GET TO THE MARKETPLACE BEFORE WE DO WITH BETTER OR
CHEAPER DRUGS, OUR DRUGS MAY NOT BE PROFITABLE TO SELL OR TO CONTINUE TO
DEVELOP.

    Each of Avant Immunotherapeutics, Inc, Leukosite Inc., a subsidiary of
Millenium Pharmaceuticals, Inc., Tanox, Inc., Abbott Laboratories,
Gliatech Inc. and Biocryst Pharmaceuticals have publicly announced their
intentions to develop drugs which target the inflammatory effects of complement
in the immune system. We are also aware that Pfizer, Inc., SmithKline Beecham
Plc and Merck & Co., Inc. are also attempting to develop complement inhibitor
therapies. Each of Cambridge Antibody Technology, PLC, MorphoSys AG and Dyax
Corporation have publicly announced intentions to develop therapeutic human
antibodies from libraries of human antibody genes. Additionally, each of
Abgenix Inc. and Medarex, Inc. have publicly announced intentions to develop
therapeutic human antibodies from mice that have been bred to include some human
antibody genes. These and other large pharmaceutical companies with
significantly greater resources than ours, may develop, manufacture and market
better or cheaper drugs than our product candidates. They may establish
themselves in the marketplace before we are able to even finish our clinical
trials. Larger pharmaceutical companies also compete with us to attract academic
research institutions as drug development partners, including for licensing
these institutions' proprietary technology. If our competitors successfully
enter into such arrangements with academic institutions, we will be precluded
from pursuing those specific unique opportunities and may not be able to find
equivalent opportunities elsewhere.

    IF WE FAIL TO RECRUIT AND RETAIN PERSONNEL, OUR RESEARCH AND PRODUCT
DEVELOPMENT PROGRAMS MAY BE DELAYED.

    We are highly dependent upon the efforts of our senior management and
scientific personnel. There is intense competition for qualified scientific and
technical personnel. Since our business is very science-oriented and
specialized, we need to continue to attract and retain such people. We may not
be able to continue to attract and retain the qualified personnel necessary for
developing our business. If we lose the services of, or fail to recruit, key
scientific and technical personnel, our research and product development
programs would be significantly and detrimentally affected.

    In particular, we highly value the services of Dr. Leonard Bell, our
President and Chief Executive Officer. The loss of his services could materially
and adversely affect our ability to achieve our development objectives.

                                       9
<PAGE>
    THE RIGHTS THAT HAVE BEEN AND MAY IN THE FUTURE BE GRANTED TO OUR
STOCKHOLDERS MAY FRUSTRATE ATTEMPTS BY OTHERS TO TAKE OVER OUR COMPANY.

    We have in place a shareholder rights plan, or "poison pill," which enables
our board of directors to issue rights to purchase preferred stock when someone
acquires 20% or more of the outstanding shares of our common stock. As a result
of the plan, anyone wishing to take over the company would most likely be forced
to negotiate a transaction with the company in order not to trigger the pill. If
we refused to negotiate, or negotiations were unsuccessful, a proposed takeover
could be frustrated. This would prevent our stockholders from participating in a
takeover or tender offer which might be of substantial value to them.

    In addition, under our certificate of incorporation, our board of directors
is authorized to issue one or more series of preferred stock with rights and
preferences determined by the board. The preferences and rights of any preferred
stock may be superior to those of the holders of our common stock. By issuing
preferred stock with superior right to the common stock, the board could
frustrate a person who wishes to take over the company through a tender offer
for the outstanding common stock. These provisions are also intended to
encourage any person interested in acquiring us to negotiate with and obtain the
approval of our board of directors. These provisions could also delay, deter or
frustrate a merger or change in control.

                                       10
<PAGE>
               SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

    This prospectus contains some "forward-looking statements" as defined in the
Private Securities Litigation Reform Act of 1995 and information relating to us
that are based on the beliefs of our management, as well as assumptions made by
and the information currently available to our management. When used in this
prospectus, the words "estimate," "project," "believe," "anticipate," "intend,"
"expect" and similar expressions are intended to identify forward-looking
statements. These statements reflect our current views with respect to future
events and are subject to risks and uncertainties that could cause actual
results to differ materially from those contemplated in these forward-looking
statements, including those risks discussed in this prospectus.

    You are cautioned not to place undue reliance on these forward-looking
statements, which speak only as of the date of this prospectus. Except for
special circumstances in which a duty to update arises when prior disclosure
becomes materially misleading in light of subsequent events, we do not intend to
update any of these forward-looking statements to reflect events or
circumstances after the date of this prospectus or to reflect the occurrence of
unanticipated events.

                                USE OF PROCEEDS

    Unless we otherwise specify in the applicable prospectus supplement, we
intend to use the net proceeds from the sale of the securities to fund research
and clinical development activities, manufacturing development, manufacturing
and commercialization of our product candidates, drug discovery, as well as for
working capital and general corporate purposes, including for potential
acquisitions of additional technologies and compounds. Our management will have
broad discretion in the allocation of the net proceeds of the offering. Pending
such uses, we intend to invest the net proceeds in short-term, investment grade,
interest-bearing securities.

                                       11
<PAGE>
                         DESCRIPTION OF DEBT SECURITIES

    The debt securities may be issued in one or more separate series of senior
debt securities and/or subordinated debt securities. The prospectus supplement
relating to the particular series of debt securities being offered will specify
the particular amounts, prices and terms of those debt securities. These terms
may include:

    - the title of the debt securities;

    - any limit upon the aggregate principal amount of the debt securities;

    - the maturity date or dates, or the method of determining the maturity
      dates;

    - the interest rate or rates, or the method of determining those rates;

    - the interest payment dates and, for debt securities in registered form,

    - the regular record dates;

    - the places where payments may be made;

    - any mandatory or optional redemption provisions;

    - any sinking fund or analogous provisions;

    - any conversion or exchange provisions;

    - any terms for the attachment to the debt securities of warrants, options
      or other rights to purchase or sell our securities;

    - the portion of principal amount of the debt security payable upon
      acceleration of maturity if other than the full principal amount;

    - any deletions of, or changes or additions to, the events of default or
      covenants;

    - if other than U.S. dollars, the currency or currencies, including the euro
      and other composite currencies, in which payments on the debt securities
      will be payable and whether the holder may elect payment to be made in a
      different currency;

    - the method of determining the amount of any payments on the debt
      securities which are linked to an index;

    - whether the debt securities will be issued in fully registered form
      without coupons or in bearer form, with or without coupons, or any
      combination of these, and whether they will be issued in the form of one
      or more global securities in temporary or definitive form;

    - any terms relating to the delivery of the debt securities if they are to
      be issued upon the exercise of warrants;

    - whether and on what terms we will pay additional amounts to holders of the
      debt securities that are not U.S. persons for any tax, assessment or
      governmental charge withheld or deducted and, if so, whether and on what
      terms we will have the option to redeem the debt securities rather than
      pay the additional amounts; and

    - any other specific terms of the debt securities.

                                       12
<PAGE>
                          DESCRIPTION OF COMMON STOCK

    As of the date of this prospectus, we are authorized to issue up to
25,000,000 shares of common stock, $.0001 par value per share. As of October 5,
2000, 15,494,671 shares of common stock were outstanding.

DIVIDENDS

    Holders of common stock are entitled to receive dividends, in cash,
securities, or property, as may from time to time be declared by our Board of
Directors, subject to the rights of the holders of the preferred stock.

VOTING

    Each holder of common stock is entitled to one vote per share on all matters
requiring a vote of the stockholders.

RIGHTS UPON LIQUIDATION

    In the event of our voluntary or involuntary liquidation, dissolution, or
winding up, the holders of common stock will be entitled to share equally in our
assets available for distribution after payment in full of all debts and after
the holders of preferred stock have received their liquidation preferences in
full.

MISCELLANEOUS

    Shares of common stock are not redeemable and have no subscription,
conversion or preemptive rights.

                            DESCRIPTION OF WARRANTS

    We may issue warrants for the purchase of debt securities or common stock.
Warrants may be issued independently or together with our debt securities or
common stock and may be attached to or separate from any offered securities.
Each series of warrants will be issued under a separate warrant agreement to be
entered into between us and a bank or trust company, as warrant agent. The
warrant agent will act solely as our agent in connection with the warrants and
will not have any obligation or relationship of agency or trust for or with any
holders or beneficial owners of warrants. A copy of the warrant agreement will
be filed with the SEC in connection with the offering of warrants.

DEBT WARRANTS

    The prospectus supplement relating to a particular issue of warrants to
issue debt securities will describe the terms of those warrants, including the
following:

    - the title of the warrants;

    - the offering price for the warrants, if any;

    - the aggregate number of the warrants;

    - the designation and terms of the debt securities purchasable upon exercise
      of the warrants;

    - if applicable, the designation and terms of the debt securities that the
      warrants are issued with and the number of warrants issued with each debt
      security;

    - if applicable, the date from and after which the warrants and any debt
      securities issued with them will be separately transferable;

                                       13
<PAGE>
    - the principal amount of debt securities that may be purchased upon
      exercise of a warrant and the price at which the debt securities may be
      purchased upon exercise;

    - the dates on which the right to exercise the warrants will commence and
      expire;

    - if applicable, the minimum or maximum amount of the warrants that may be
      exercised at any one time;

    - whether the warrants represented by the warrant certificates or debt
      securities that may be issued upon exercise of the warrants will be issued
      in registered or bearer form;

    - information relating to book-entry procedures, if any;

    - the currency or currency units in which the offering price, if any, and
      the exercise price are payable;

    - if applicable, a discussion of material United States federal income tax
      considerations;

    - anti-dilution provisions of the warrants, if any;

    - redemption or call provisions, if any, applicable to the warrants; and

    - any additional terms of the warrants, including terms, procedures and
      limitations relating to the exchange and exercise of the warrants.

STOCK WARRANTS

    The prospectus supplement relating to a particular issue of warrants to
issue common stock will describe the terms of the warrants, including the
following:

    - the title of the warrants;

    - the offering price for the warrants, if any;

    - the aggregate number of the warrants;

    - the designation and terms of the common stock that may be purchased upon
      exercise of the warrants;

    - if applicable, the designation and terms of the securities that the
      warrants are issued with and the number of warrants issued with each
      security;

    - if applicable, the date from and after which the warrants and any
      securities issued with the warrants will be separately transferable;

    - the number of shares of common stock that may be purchased upon exercise
      of a warrant and the price at which the shares may be purchased upon
      exercise;

    - the dates on which the right to exercise the warrants commence and expire;

    - if applicable, the minimum or maximum amount of the warrants that may be
      exercised at any one time;

    - the currency or currency units in which the offering price, if any, and
      the exercise price are payable;

    - if applicable, a discussion of material United States federal income tax
      considerations;

    - anti-dilution provisions of the warrants, if any;

    - redemption or call provisions, if any, applicable to the warrants;

    - any additional terms of the warrants, including terms, procedures and
      limitations relating to the exchange and exercise of the warrants; and

    - any other information we think is important about the warrants.

                                       14
<PAGE>
                              PLAN OF DISTRIBUTION

    We may sell the securities:

    - through underwriters;

    - through agents; or

    - directly to purchasers.

    We will describe in a prospectus supplement, the particular terms of the
offering of the securities, including the following:

    - the names of any underwriters;

    - the purchase price and the proceeds we will receive from the sale;

    - any underwriting discounts and other items constituting underwriters'
      compensation;

    - any initial public offering price and any discounts or concessions allowed
      or reallowed or paid to dealers;

    - any securities exchanges on which the securities of the series may be
      listed; and

    - any other information we think is important.

    If we use underwriters in the sale, the securities will be acquired by the
underwriters for their own account and may be resold from time to time in one or
more transactions, including negotiated transactions, either at a fixed public
offering price, or at varying prices determined at the time of sale.

    The securities may be either offered to the public through underwriting
syndicates represented by managing underwriters or by underwriters without a
syndicate. The obligations of the underwriters to purchase securities will be
subject to conditions precedent, and the underwriters will be obligated to
purchase all the securities of a series if any are purchased. Any initial public
offering price and any discounts or concessions allowed or reallowed or paid to
dealers may be changed from time to time.

    Securities may be sold directly by us or through agents designated by us
from time to time. Any agent involved in the offer or sale of the securities for
which this prospectus is delivered will be named, and any commissions payable by
us to that agent will be set forth, in the prospectus supplement. Unless
otherwise indicated in the prospectus supplement, any agent will be acting on a
best efforts basis for the period of its appointment.

    We may authorize agents or underwriters to solicit offers by certain types
of institutions to purchase securities from us at the public offering price set
forth in the prospectus supplement pursuant to delayed delivery contracts. These
contracts will provide for payment and delivery on a specified date in the
future. The conditions to these contracts and the commissions payable for
solicitation of such contracts will be set forth in the applicable prospectus
supplement.

    Agents and underwriters may be entitled to indemnification by us against
civil liabilities arising out of this prospectus, including liabilities under
the Securities Act of 1933, or to contribution for payments which the agents or
underwriters may be required to make relating to those liabilities. Agents and
underwriters may be customers of, engage in transactions with, or perform
services for, us in the ordinary course of business.

    Any series of securities may be a new issue of securities with no
established trading market. Any underwriter may make a market in the securities,
but won't be obligated to do so, and may discontinue any market making at any
time without notice. We can't and won't give any assurances as to the liquidity
of the trading market for any of our securities.

                                 LEGAL MATTERS

    Fulbright & Jaworski L.L.P., New York, New York, will pass upon the validity
of the securities offered hereby and some other legal matters on behalf of
Alexion.

                                       15
<PAGE>
                                    EXPERTS

    The audited consolidated financial statements, incorporated by reference in
this prospectus and elsewhere in the registration statement have been audited by
Arthur Andersen LLP, independent public accountants, as indicated in their
report with respect thereto, and are included herein in reliance upon the
authority of said firm as experts in accounting and auditing in giving said
report.

                      WHERE YOU CAN FIND MORE INFORMATION

    We file annual, quarterly and special reports, proxy statements and other
information with the Securities and Exchange Commission. You may read and copy
any reports, statements or other information filed by us at the Commission's
public reference room at Room 1024, Judiciary Plaza, 450 Fifth Street, N.W.,
Washington, D.C. 20549 and the regional offices of the Commission located at
Seven World Trade Center, 13th Floor, New York, New York 10048, and 500 West
Madison Street, Chicago, Illinois 60661. Copies of such material can be also
obtained from the Public Reference Section of the Commission at 450 Fifth
Street, N.W., Washington, D.C. 20549, and its public reference rooms in New
York, New York and Chicago, Illinois, at prescribed rates. Please call the
Commission at 1-800-SEC-0330 for further information on the public reference
rooms. Copies of such information may also be inspected at the reading room of
the library of the National Association of Securities Dealers, Inc., 1735 K
Street, N.W., Washington, D.C. 20006. Our filings with the Commission are also
available to the public from commercial document retrieval services and at the
Commission's web site at "http://www.sec.gov."

    We "incorporate by reference" the information we file with the Commission
(File No. 0-27756), which means that we can disclose important information to
you by referring you to another document we filed with the Commission. The
information incorporated by reference is an important part of this prospectus,
and information that we file later with the Commission will automatically update
and supersede this information. We incorporate by reference the documents listed
below and any filings made with the Commission under Sections 13(a), 13(c), 14
or 15(d) of the Securities Exchange Act of 1934, as amended, after the date of
this prospectus but before the end of any offering made under this prospectus:

    - our current reports on Form 8-K, filed on September 25, 2000 and
      October 3, 2000;

    - our annual report on Form 10-K for the fiscal year ended July 31, 2000,
      filed on October 6, 2000;

    - our registration statement on Form 8-A, filed on February 21, 1997, as
      amended on October 6, 2000; and

    - our registration statement on Form 8-A, filed on February 12, 1996.

    You should read the information relating to us in this prospectus together
with the information in the documents incorporated by reference.

    Any statement contained in a document incorporated by reference herein,
unless otherwise indicated therein, speaks as of the date of the document.
Statements contained in this prospectus may modify or replace statements
contained in the documents incorporated by reference.

    We will furnish without charge to you, upon written or oral request, a copy
of any or all of the documents described above, except for exhibits to such
documents, unless such exhibits are specifically incorporated by reference into
such documents. Requests should be addressed to: Alexion Pharmaceuticals, Inc.,
25 Science Park, New Haven, Connecticut 06511, (203) 776-1790, Attention: David
W. Keiser, Executive Vice President and Chief Operating Officer.

                                       16
<PAGE>
                                     [LOGO]

                                  $300,000,000
                                DEBT SECURITIES
                                  COMMON STOCK
                                    WARRANTS

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

                                   PROSPECTUS

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

                                October   , 2000
<PAGE>
                                    PART II

ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

    The following table sets forth Alexion Pharmaceuticals, Inc. (the "Company")
estimates (other than the SEC registration fee) of the expenses in connection
with the issuance and distribution of the securities being registered. None of
the following expenses are being paid by the selling stockholders.

<TABLE>
<S>                                                           <C>
SEC registration fee........................................  $ 79,200.00
Legal fees and expenses.....................................  $100,000.00
Accounting fees and expenses................................  $ 65,000.00
Miscellaneous expenses......................................  $155,800.00
                                                              -----------
    Total:                                                    $400,000.00
                                                              ===========
</TABLE>

ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

    Section 145 of the Delaware General Corporation Law (the "DGCL") empowers a
Delaware corporation to indemnify any person who was or is a party or is
threatened to be made a party to any threatened, pending or completed action,
suit or proceeding, whether civil, criminal, administrative or investigative
(other than an action by or in the right of such corporation) by reason of the
fact that such person is or was a director, officer, employee or agent of such
corporation, or is or was serving at the request of such corporation as a
director, officer, employee or agent of another corporation or enterprise. A
corporation may, in advance of the final disposition of any civil, criminal,
administrative or investigative action, suit or proceeding, pay the expenses
(including attorneys' fees) incurred by any officer, director, employee or agent
in defending such action, provided that the director or officer undertakes to
repay such amount if it shall ultimately be determined that he is not entitled
to be indemnified by the corporation. A corporation may indemnify such person
against expenses (including attorneys' fees), judgments, fines and amounts paid
in settlement actually and reasonably incurred by such person in connection with
such action, suit or proceeding if he acted in good faith and in a manner he
reasonably believed to be in or not opposed to the best interests of the
corporation, and, with respect to any criminal action or proceeding, had no
reasonable cause to believe his conduct was unlawful.

    A Delaware corporation may indemnify officers and directors in an action by
or in the right of the corporation to procure a judgment in its favor under the
same conditions, except that no indemnification is permitted without judicial
approval if the officer or director is adjudged to be liable to the corporation.
Where an officer or director is successful on the merits or otherwise in the
defense of any action referred to above, the corporation must indemnify him
against the expenses (including attorneys fees) which he actually and reasonably
incurred in connection therewith. The indemnification provided is not deemed to
be exclusive of any other rights to which an officer or director may be entitled
under any corporation's by-law, agreement, vote or otherwise.

    In accordance with Section 145 of the DGCL, Section EIGHTH of the Company's
Certificate of Incorporation, as amended (the "Certificate") provides that the
Company shall indemnify each person who is or was a director, officer, employee
or agent of the Company (including the heirs, executors, administrators or
estate of such person) or is or was serving at the request of the Company as a
director, officer, employee or agent of another corporation, partnership, joint
venture, trust or other enterprise, to the fullest extent permitted. The
indemnification provided by the Certificate shall not be deemed exclusive of any
other rights to which any of those seeking indemnification or advancement of
expenses may be entitled under any by-law, agreement, vote of shareholders or
disinterested directors or otherwise, both as to action in his official capacity
and as to action in another capacity while holding such office, and shall
continue as to a person who has ceased to be a director, officer, employee or

                                      II-1
<PAGE>
agent and shall inure to the benefit of the heirs, executors and administrators
of such a person. Expenses (including attorneys' fees) incurred in defending a
civil, criminal, administrative or investigative action, suit or proceeding
shall be paid by the Company in advance of the final disposition of such action,
suit or proceeding upon receipt of an undertaking by or on behalf of the
indemnified person to repay such amount if it shall ultimately be determined
that he is not entitled to be indemnified by the Company. Section NINTH of the
Certificate provides that a director of the Company shall not be personally
liable to the Company or its stockholders for monetary damages for breach of
fiduciary duty as a director, except for liability (i) for any breach of the
director's duty of loyalty to the Company or its stockholders, (ii) for acts or
omissions not in good faith or which involve intentional misconduct or a knowing
violation of law, (iii) under Section 174 of the DGCL, or (iv) for any
transaction from which the director derived an improper personal benefit.

ITEM 16. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.

    (a) Exhibits.

<TABLE>
<C>                     <S>
5.1.........            Opinion of Fulbright & Jaworski L.L.P. regarding legality.*
12.1........            Statement of Computation of Ratios.+
23.1........            Consent of Fulbright & Jaworski L.L.P. (included in Exhibit
                        5.1).*
23.2........            Consent of Arthur Andersen LLP.+
24.1........            Power of Attorney (included on signature page).
</TABLE>

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

*   To be filed by amendment.

+   Filed herewith.

    (b) Financial Statement Schedules.

    None.

ITEM 17. UNDERTAKINGS.

    (a) The undersigned Registrant hereby undertakes:

        (1) To file, during any period in which offers or sales are being made,
    a post-effective amendment of this registration statement;

           (i) To include any prospectus required by Section 10(a)(3) of the
       Securities Act of 1933;

           (ii) To reflect in the prospectus any facts or events arising after
       the effective date of the registration statement (or the most recent
       post-effective amendment thereof) which, individually or in the
       aggregate, represent a fundamental change in the information set forth in
       the registration statement; and

           (iii) To include any material information with respect to the plan of
       distribution not previously disclosed in the registration statement of
       any material change to such information in the registration statement.

    Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if
the information required to be included in a post-effective amendment by those
paragraphs is contained in periodic reports filed by the registrant pursuant to
Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are
incorporated by reference in the registration statement.

        (2) That, for the purpose of determining any liability under the
    Securities Act of 1933, each such post-effective amendment shall be deemed
    to be a new registration statement relating to the

                                      II-2
<PAGE>
    securities offered therein, and the offering of such securities at that time
    shall be deemed to be the initial BONA FIDE offering thereof.

        (3) To remove from registration by means of a post-effective amendment
    any of the securities being registered which remain unsold at the
    termination of the offering.

        (4) To deliver or cause to be delivered with the prospectus, to each
    person to whom the prospectus is sent or given, the latest annual report, to
    security holders that is incorporated by reference in the prospectus and
    furnished pursuant to and meeting the requirements of Rule 14a-3 or
    Rule 14c-3 under the Securities Exchange Act of 1934; and, where interim
    financial information required to be presented by Article 3 of
    Regulation S-X is not set forth in the prospectus, to deliver, or cause to
    be delivered to each person to whom the prospectus is sent or given, the
    latest quarterly report that is specifically incorporated by reference in
    the prospectus to provide such interim financial information.

        (5) That, for purposes of determining any liability under the Securities
    Act of 1933, each filing of the registrant's annual report pursuant to
    Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 that
    is incorporated by reference in the registration statement shall be deemed
    to be a new registration statement relating to the securities offered
    therein, and the offering of such securities at that time shall be deemed to
    be the initial BONA FIDE offering thereof.

        (6) Insofar as indemnification for liabilities arising under the
    Securities Act of 1933 may be permitted to directors, officers and
    controlling persons of the registrant pursuant to the provisions described
    under Item 15 above, or otherwise, the registrant has been advised that in
    the opinion of the Securities and Exchange Commission such indemnification
    is against public policy expressed in the Act and is, therefore,
    unenforceable. In the event that a claim for indemnification against such
    liabilities (other than the payment by the registrant of expenses incurred
    or paid by a director, officer or controlling person of the registrant in
    the successful defense of any action, suit or proceeding) is asserted by
    such director, officer or controlling person in connection with the
    securities being registered, the registrant will, unless in the opinion of
    its counsel the matter has been settled by controlling precedent, submit to
    a court of appropriate jurisdiction the question whether such
    indemnification by it is against public policy as expressed in the Act and
    will be governed by the final adjudication of such issue.

                                      II-3
<PAGE>
                                   SIGNATURES

    Pursuant to the requirements of the Securities Act of 1933, as amended, the
registrant has duly caused this registration statement to be signed on its
behalf by the undersigned, thereunto duly authorized, in the City of New Haven
and State of Connecticut on the 5th day of October, 2000.

<TABLE>
<S>                                                    <C>  <C>
                                                       ALEXION PHARMACEUTICALS, INC.

                                                       By:               /s/ LEONARD BELL
                                                            -----------------------------------------
                                                                        Leonard Bell, M.D.
                                                               PRESIDENT, CHIEF EXECUTIVE OFFICER,
                                                                     SECRETARY AND TREASURER
</TABLE>

                               POWER OF ATTORNEY

    KNOW ALL MEN BY THESE PRESENTS, that each individual whose signature appears
below constitutes and appoints LEONARD BELL, M.D. and DAVID W. KEISER, or either
of them, his true and lawful attorney-in-fact and agent with full power of
substitution and resubstitution, for him and in his name, place and stead, in
any and all capacities, to sign any and all amendments (including post-effective
amendments) to this Registration Statement, and to file the same with all
exhibits thereto, and all documents in connection therewith, with the Securities
and Exchange Commission, granting said attorney-in-fact and agent, and each of
them, full power and authority to do and perform each and every act and thing
requisite and necessary to be done in and about the premises, as fully to all
intents and purposes as he or she might or could do in person, hereby ratifying
and confirming all that said attorney-in-fact and agent or any of them, or their
or his substitute or substitutes, may lawfully do or cause to be done by virtue
hereof.

    Pursuant to the requirements of the Securities Act of 1933, as amended, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated:

<TABLE>
<CAPTION>
                        NAME                                      TITLE                    DATE
                        ----                                      -----                    ----
<C>                                                    <S>                          <C>
                                                       President, Chief Executive
                  /s/ LEONARD BELL                       Officer, Secretary,
     -------------------------------------------         Treasurer and Director      October 5, 2000
                 Leonard Bell, M.D.                      (principal executive
                                                         officer)

                                                       Executive Vice President
                 /s/ DAVID W. KEISER                     and Chief Operating
     -------------------------------------------         Officer                     October 5, 2000
                   David W. Keiser                       (principal financial
                                                         officer)

                                                       Vice President of Finance
                  /s/ BARRY P. LUKE                      and Administration
     -------------------------------------------         (principal accounting       October 5, 2000
                    Barry P. Luke                        officer)

                  /s/ JOHN H. FRIED
     -------------------------------------------       Chairman of the Board of      October 5, 2000
                 John H. Fried Ph.D.                     Directors
</TABLE>

                                      II-4
<PAGE>

<TABLE>
<CAPTION>
                        NAME                                      TITLE                    DATE
                        ----                                      -----                    ----
<C>                                                    <S>                          <C>
                /s/ JERRY T. JACKSON
     -------------------------------------------       Director                      October 5, 2000
                  Jerry T. Jackson

                    /s/ MAX LINK
     -------------------------------------------       Director                      October 5, 2000
                   Max Link, Ph.D.

                 /s/ JOSEPH A. MADRI
     -------------------------------------------       Director                      October 5, 2000
            Joseph A. Madri, Ph.D., M.D.

                  /s/ LEONARD MARKS
     -------------------------------------------       Director                      October 5, 2000
              Leonard Marks, Jr., Ph.D.

                /s/ R. DOUGLAS NORBY
     -------------------------------------------       Director                      October 5, 2000
                  R. Douglas Norby

                 /s/ ALVIN S. PARVEN
     -------------------------------------------       Director                      October 5, 2000
                   Alvin S. Parven
</TABLE>

                                      II-5
<PAGE>
                                 EXHIBIT INDEX

<TABLE>
<CAPTION>
       EXHIBIT
       NUMBER           EXHIBIT
       -------          -------
<C>                     <S>
         5.1            Opinion of Fulbright & Jaworski L.L.P. regarding legality.*
        12.1            Statement of Computation of Ratios.+
        23.1            Consent of Fulbright & Jaworski L.L.P. (included in Exhibit
                        5.1).*
        23.2            Consent of Arthur Andersen LLP.+
        24.1            Power of Attorney (included on signature page).
</TABLE>

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

*   To be filed by amendment.

+   Filed herewith.


© 2022 IncJournal is not affiliated with or endorsed by the U.S. Securities and Exchange Commission