SECURITIES AND EXCHANGE COMMISSION
                               Washington, D.C. 20549


                                    SCHEDULE 13G

                      Under the Securities Exchange Act of 1934


                                  (Amendment No. )*



                           Alexion Pharmaceuticals, Inc.

                                  (Name of Issuer)

                                    Common Stock

                           (Title of Class of Securities)

                                     015351109

                                   (CUSIP Number)

                                 December 29, 2000

              (Date of Event Which Requires Filing of This Statement)


     Check the appropriate box to designate the rule pursuant to which this
     Schedule is filed:
     [X] Rule 13d-1(b)
     [ ] Rule 13d-1(c)
     [ ] Rule 13d-1(d)


     *The remainder of this cover page shall be filled out for a reporting
     person's initial filing on this form with respect to the subject class of
     securities, and for any subsequent amendment containing information which
     would alter the disclosures provided in a prior cover page.

     The information required in the remainder of this cover page shall not be
     deemed to be "filed" for the purpose of Section 18 of the Securities
     Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of
     that section of the Act but shall be subject to all other provisions of the
     Act (however, see the Notes).














     







      1   NAMES OF REPORTING PERSONS
          I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
          Capital Research and Management Company
          95-1411037

      2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE
          INSTRUCTIONS)                                                 (a)

                                                                         (b)

      3   SEC USE ONLY




      4   CITIZENSHIP OR PLACE OF ORGANIZATION

          Delaware


                   5   SOLE VOTING POWER

                       NONE


                   6   SHARED VOTING POWER
      NUMBER OF
        SHARES
                       NONE
     BENEFICIALL
      Y OWNED BY
                   7   SOLE DISPOSITIVE POWER
         EACH
      REPORTING
                       920,000
        PERSON
        WITH:

                   8   SHARED DISPOSITIVE POWER

                       NONE


      9   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

          920,000   Beneficial ownership disclaimed pursuant to Rule 13d-4


      10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
          (SEE INSTRUCTIONS)



      11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

          5.1%


      12  TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

          IA







     







      1   NAMES OF REPORTING PERSONS
          I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
          The Growth Fund of America, Inc.
          52-0792143

      2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE
          INSTRUCTIONS)                                                 (a)

                                                                         (b)

      3   SEC USE ONLY




      4   CITIZENSHIP OR PLACE OF ORGANIZATION

          Maryland


                   5   SOLE VOTING POWER

                       920,000


                   6   SHARED VOTING POWER
      NUMBER OF
        SHARES
                       NONE
     BENEFICIALL
      Y OWNED BY
                   7   SOLE DISPOSITIVE POWER
         EACH
      REPORTING
                       NONE
        PERSON
        WITH:

                   8   SHARED DISPOSITIVE POWER

                       NONE


      9   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

          920,000


      10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
          (SEE INSTRUCTIONS)



      11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

          5.1%


      12  TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

          IV







     


                         SECURITIES AND EXCHANGE COMMISSION
                                Washington, DC 20549

                                    Schedule 13G
                      Under the Securities Exchange Act of 1934


     Amendment No.

     Item 1(a)   Name of issuer:
            Alexion Pharmaceuticals, Inc.

     Item 1(b)   Address of issuer's principal executive offices:
            352 Knotter Drive
            Cheshire, CT 06410

     Item 2(a)   Name of person(s) filing:
            Capital Research and Management Company and The Growth Fund of
            America, Inc.

     Item 2(b)   Address or principal business office or, if none, residence:
            333 South Hope Street
            Los Angeles, CA  90071

     Item 2(c)   Citizenship:   N/A

     Item 2(d)   Title of class of securities:
            Common Stock

     Item 2(e)   CUSIP No.:
            015351109

     Item 3   If this statement is filed pursuant to sections 240.13d-1(b) or
            240.13d-2(b) or (c), check whether the person filings is a:
            (d)   [X]   Investment Company registered under section 8 of the
                 Investment Company Act of 1940 (15 U.S.C. 80a-8).
            (e)    [X]   An investment adviser in accordance with section
                 240.13d-1(b)(1)(ii)(E).

     Item 4   Ownership

            Provide the following information regarding the aggregate number
            and percentage of the class of securities of the issuer identified
            in Item 1.

            See pages 2 and 3

            (a)    Amount beneficially owned:
            (b)    Percent of class:
            (c)    Number of shares as to which the person has:
            (i)    Sole power to vote or to direct the vote:
            (ii)   Shared power to vote or to direct the vote:
            (iii)  Sole power to dispose or to direct the disposition of:
            (iv)   Shared power to dispose or to direct the disposition of:








     






            Capital Research and Management Company, an investment adviser
            registered under Section 203 of the Investment Advisers Act of 1940
            is deemed to be the beneficial owner of 920,000 shares or 5.1% of
            the 18,016,000 shares of Common Stock believed to be outstanding as
            a result of acting as investment adviser to various investment
            companies registered under Section 8 of the Investment Company Act
            of 1940.

            The Growth Fund of America, Inc., an investment company registered
            under the Investment Company Act of 1940, which is advised by
            Capital Research and Management Company, is the beneficial owner of
            920,000 shares or 5.1% of the 18,016,000 shares of Common Stock
            believed to be outstanding.

     Item 5   Ownership of 5 percent or Less of a Class.  If this statement is
            being filed to report the fact that as of the date hereof the
            reporting person has ceased to be the beneficial owner of more than
            5 percent of the class of securities, check the following: [ ]

     Item 6   Ownership of More than 5% on Behalf of Another Person: N/A

     Item 7   Identification and Classification of the Subsidiary Which Acquired
            the Security Being Reported on By the Parent Holding Company or
            Control Person.: N/A

     Item 8   Identification and Classification of Members of the Group:  N/A

     Item 9   Notice of Dissolution of Group:  N/A

     Item 10   Certification

            By signing below, I certify that, to the best of my knowledge and
            belief, the securities referred to above were acquired and are held
            in the ordinary course of business and were not acquired and are
            not held for the purpose of or with the effect of changing or
            influencing the control of the issuer of the securities and were
            not acquired and are not held in connection with or as a
            participant in any transaction having that purpose or effect.

        Signature

            After reasonable inquiry and to the best of my knowledge and
            belief, I certify that the information set forth in this statement
            is true, complete and correct.



             Date:          February 9, 2001


             Signature:     *Paul G. Haaga, Jr.

             Name/Title:    Paul G. Haaga, Jr., Executive Vice
                            President

                            Capital Research and Management Company



     CUSIP: 015351109                                                Page 5 of 7








             Date:          February 9, 2001


             Signature:     *Paul G. Haaga, Jr.

             Name/Title:    Paul G. Haaga, Jr., Senior Vice President

                            The Growth Fund of America, Inc.




             *By

                    James P. Ryan
                    Attorney-in-fact

                    Signed pursuant to a Power of Attorney dated December 19,
                    2000 included as an Exhibit to Schedule 13G filed with the
                    Securities and Exchange Commission by Capital Research and
                    Management Company on February 9, 2001 with respect to 3COM
                    Corporation.





































     CUSIP: 015351109                                                Page 6 of 7


                                      AGREEMENT

                                   Los Angeles, CA
                                  February 9, 2001


       Capital Research and Management Company ("CRMC") and The Growth Fund of
     America, Inc. ("GFA") hereby agree to file a joint statement on Schedule
     13G under the Securities Exchange Act of 1934 (the "Act") in connection
     with their beneficial ownership of Common Stock issued by Alexion
     Pharmaceuticals, Inc.

       CRMC and GFA state that they are each entitled to individually use
     Schedule 13G pursuant to Rule 13d-1(c) of the Act.

       CRMC and GFA are each responsible for the timely filing of the statement
     and any amendments thereto, and for the completeness and accuracy of the
     information concerning each of them contained therein but are not
     responsible for the completeness or accuracy of the information concerning
     the others.



                      CAPITAL RESEARCH AND MANAGEMENT COMPANY

                      BY:              *Paul G. Haaga, Jr.

                                        Paul G. Haaga, Jr., Executive
                                        Vice President
                                        Capital Research and Management
                                        Company


                      THE GROWTH FUND OF AMERICA, INC.

                      BY:              *Paul G. Haaga, Jr.

                                        Paul G. Haaga, Jr., Senior Vice
                                        President
                                        The Growth Fund of America,
                                        Inc.


     *By

          James P. Ryan
          Attorney-in-fact

          Signed pursuant to a Power of Attorney dated December 19, 2000
          included as an Exhibit to Schedule 13G filed with the Securities and
          Exchange Commission by Capital Research and Management Company on
          February 9, 2001 with respect to 3COM Corporation.