SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

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

                                  SCHEDULE 13G
                                 (Rule 13d-102)

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

    INFORMATION TO BE INCLUDED IN STATEMENTS PURSUANT TO RULES 13d-1(b), (c)
          AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO 13d-2 UNDER
                       THE SECURITIES EXCHANGE ACT OF 1934

                          ALEXION PHARMACEUTICALS, INC.
                                (Name of Issuer)

                         COMMON STOCK, PAR VALUE $0.0001
                         (Title of Class of Securities)

                                    015351109
                                 (CUSIP Number)

                                 March 19, 2007
             (Date of Event Which Requires Filing of this Statement)

     Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:

     [ ] Rule 13d-1(b)

     [X] 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 (the "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).







Schedule 13G
CUSIP No. 015351109                                                Page 2 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Davidson Kempner Partners
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY

--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       New York
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 134,915

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 134,915
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 134,915
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                0.4%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                PN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                                Page 3 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Davidson Kempner Institutional Partners, L.P.
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       Delaware
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 226,517

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 226,517
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 226,517
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                0.6%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                PN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                                Page 4 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      M. H. Davidson  & Co.
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       New York
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 22,304

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 22,304
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 22,304
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                0.1%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                PN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                                Page 5 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Davidson Kempner International, Ltd.
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       British Virgin Islands
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 345,525

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 345,525
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 345,525
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                1.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                CO
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                                Page 6 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Serena Limited
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       Cayman Islands
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 9,930

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 9,930
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 9,930
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                0.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                CO
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                                Page 7 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Davidson Kempner Healthcare Fund LP
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       Delware
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 465,022

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 465,022
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 465,022
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                1.3%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                PN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                                Page 8 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Davidson Kempner Healthcare International Ltd.
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       Cayman Islands
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 599,933

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 599,933
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 599,933
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                1.7%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                CO
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                                Page 9 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      MHD Management Co.
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       New York
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 134,915

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 134,915
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 134,915
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                0.4%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                PN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                               Page 10 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Davidson Kempner Advisers Inc.
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       New York
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 226,517

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 226,517
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 226,517
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                0.6%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                IA
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                               Page 11 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Davidson Kempner International Advisors, L.L.C.
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       Delaware
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 355,455

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 355,455
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 355,455
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                1.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                OO
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                               Page 12 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      DK Group LLC
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       Delaware
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 465,022

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 465,022
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 465,022
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                1.3%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                OO
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                               Page 13 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      DK Management Partners LP
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       Delaware
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 599,933

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 599,933
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 599,933
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                1.7%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                PN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                               Page 14 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      DK Stillwater GP LLC
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       Delaware
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 599,933

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 599,933
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 599,933
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                1.7%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                OO
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                               Page 15 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Thomas L. Kempner, Jr.
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       United States
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 1,804,146

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 1,804,146
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 1,804,146
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                5.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                IN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                               Page 16 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Marvin H. Davidson
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       United States
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 1,804,146

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 1,804,146
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 1,804,146
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                5.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                IN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                               Page 17 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Stephen M. Dowicz
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       United States
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 1,804,146

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 1,804,146
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 1,804,146
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                5.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                IN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                               Page 18 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Scott Davidson
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       United States
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 1,804,146

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 1,804,146
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 1,804,146
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                5.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                IN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                               Page 19 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Michael J. Leffell
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       United States
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 1,804,146

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 1,804,146
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 1,804,146
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                5.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                IN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                               Page 20 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Timothy I. Levart
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       United Kingdom & United States
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 1,804,146

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 1,804,146
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 1,804,146
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                5.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                IN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                              Page 21 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Robert J. Brivio, Jr.
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       United States
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 1,804,146

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 1,804,146
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 1,804,146
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                5.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                IN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                              Page 22 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Eric P. Epstein
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       United States
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 1,804,146

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 1,804,146
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 1,804,146
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                5.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                IN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                              Page 23 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Anthony A. Yoseloff
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       United States
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 1,804,146

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 1,804,146
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 1,804,146
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                5.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                IN
--------------------------------------------------------------------------------





Schedule 13G
CUSIP No. 015351109                                              Page 24 of 42

--------------------------------------------------------------------------------
(1)   NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
      Avram Z. Friedman
--------------------------------------------------------------------------------
(2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                 (a) [ ]
                                                                 (b) [X]
--------------------------------------------------------------------------------
(3)   SEC USE ONLY
--------------------------------------------------------------------------------
(4)   CITIZENSHIP OR PLACE OF ORGANIZATION
                       United States
--------------------------------------------------------------------------------

NUMBER OF         (5)  SOLE VOTING POWER
                                 0

SHARES            --------------------------------------------------------------

BENEFICIALLY      (6)  SHARED VOTING POWER
                                 1,804,146

OWNED BY          --------------------------------------------------------------

EACH              (7)  SOLE DISPOSITIVE POWER
                                 0

REPORTING         --------------------------------------------------------------

PERSON WITH       (8)  SHARED DISPOSITIVE POWER
                                 1,804,146
--------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
                                 1,804,146
--------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES                       [ ]
--------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
                                5.0%
--------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON
                                IN
--------------------------------------------------------------------------------




Schedule 13G
CUSIP No. 015351109                                              Page 25 of 42


ITEM 1(a).   NAME OF ISSUER:

             Alexion Pharmaceuticals, Inc. (the "Company")

ITEM 1(b).   ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES:

             352 Knotter Drive
             Cheshire, CT 06410

ITEM 2(a).   NAME OF PERSON FILING:

      This Statement is filed by each of the entities and persons listed
below, all of whom together are referred to herein as the "Reporting Persons":

             (i)      Davidson Kempner Partners, a New York limited
                      partnership ("DKP");

             (ii)     Davidson Kempner Institutional Partners, L.P., a
                      Delaware limited partnership ("DKIP");

             (iii)    M. H. Davidson & Co., a New York limited partnership
                      ("CO");

             (iv)     Davidson Kempner International, Ltd., a British
                      Virgin Islands corporation ("DKIL");

             (v)      Serena Limited, a Cayman Islands corporation
                      ("Serena");

             (vi)     Davidson Kempner Healthcare Fund LP, a Delaware
                      limited partnership ("DKHF");

             (vii)    Davidson Kempner Healthcare International Ltd., a
                      Cayman Islands corporation ("DKHI");

             (viii)   MHD Management Co., a New York limited partnership
                      and the general partner of DKP ("MHD");

             (ix)     Davidson Kempner Advisers Inc., a New York
                      corporation and the general partner of DKIP ("DKAI"),
                      which is registered as an investment adviser with the
                      U.S. Securities and Exchange Commission;

             (x)      Davidson Kempner International Advisors, L.L.C., a
                      Delaware limited liability company and the manager of
                      DKIL and Serena ("DKIA");

             (xi)     DK Group LLC, a Delaware limited liability company
                      and the general partner of DKHF ("DKG");




Schedule 13G
CUSIP No. 015351109                                              Page 26 of 42


             (xii)    DK Management Partners LP, a Delaware limited
                      partnership and the investment manager of DKHI
                      ("DKMP");

             (xiii)   DK Stillwater GP LLC, a Delaware limited liability
                      company and the general partner of DKMP ("DKS"); and

             (xiv)    Messrs. Thomas L. Kempner, Jr., Marvin H. Davidson,
                      Stephen M. Dowicz, Scott E. Davidson, Michael J. Leffell,
                      Timothy I. Levart, Robert J. Brivio, Jr., Anthony A.
                      Yoseloff, Eric P. Epstein and Avram Z. Friedman
                      (collectively, the "Principals"), who are the general
                      partners of CO and MHD, the sole managing members of DKIA
                      and DKG and the sole stockholders of DKAI. Messrs. Thomas
                      L. Kempner, Jr. and Timothy I. Levart are Executive
                      Managing Member and Deputy Executive Managing Member,
                      respectively, of DKS. Each of Messrs. Kempner and Levart,
                      together with Messrs. Marvin H. Davidson, Stephen M.
                      Dowicz, Scott E. Davidson, Michael J. Leffell, Robert J.
                      Brivio, Jr., Anthony A. Yoseloff, Eric P. Epstein and
                      Avram Z. Friedman are limited partners of DKMP.

ITEM 2(b).   ADDRESS OF PRINCIPAL BUSINESS OFFICE:

      The address of the principal business office of each of the Reporting
Persons is c/o Davidson Kempner Partners, 65 East 55th Street, 19th Floor, New
York, New York 10022.

ITEM 2(c).   CITIZENSHIP:

             (i)     DKP - a New York limited partnership

             (ii)    DKIP - a Delaware limited partnership

             (iii)   CO - a New York limited partnership

             (iv)    DKIL - a British Virgin Islands corporation

             (v)     Serena - a Cayman Islands corporation

             (vi)    DKHF - a Delaware limited partnership

             (vii)   DKHI - a Cayman Islands corporation

             (viii)  MHD - a New York limited partnership

             (ix)    DKAI - a New York corporation

             (x)     DKIA - a Delaware limited liability company

             (xi)    DKG - a Delaware limited liability company

             (xii)   DKMP - a Delaware limited partnership

             (xiii)  DKS - a Delaware limited liability company




Schedule 13G
CUSIP No. 015351109                                              Page 27 of 42

             (xiv)   Thomas L. Kempner, Jr. - United States

             (xv)    Marvin H. Davidson - United States

             (xvi)   Stephen M. Dowicz - United States

             (xvii)  Scott E. Davidson -United States

             (xviii) Michael J. Leffell - United States

             (xix)   Timothy I. Levart - United Kingdom & United States

             (xx)    Robert J. Brivio, Jr. - United States

             (xxi)   Eric P. Epstein - United States

             (xxii)  Anthony A. Yoseloff - United States

             (xxiii) Avram Z. Friedman - United States

ITEM 2(d).   TITLE OF CLASS OF SECURITIES:

      COMMON STOCK, PAR VALUE $0.0001

ITEM 2(e).   CUSIP NUMBER:

      015351109

ITEM 3.  IF THIS STATEMENT IS FILED PURSUANT TO 13d-1(b) OR 13d-2(b) OR (c),
CHECK WHETHER THE PERSON FILING IS A:

             (a) [ ]   Broker or dealer registered under Section 15
                       of the Act;

             (b) [ ]   Bank as defined in Section 3(a)(6) of the
                       Act;

             (c) [ ]   Insurance Company as defined in Section
                       3(a)(19) of the Act;

             (d) [ ]   Investment Company registered under Section 8
                       of the Investment Company Act of 1940;

             (e) [ ]   Investment Adviser registered under Section 203 of the
                       Investment Advisers Act of 1940: see Rule
                       13d-1(b)(1)(ii)(E);

             (f) [ ]   Employee Benefit Plan, Pension Fund which is
                       subject to the provisions of the Employee
                       Retirement Income Security Act of 1974 or
                       Endowment Fund; see Rule 13d-1(b)(1)(ii)(F);

             (g) [ ]   Parent Holding Company, in accordance with
                       Rule 13d-1(b)(ii)(G);

             (h) [ ]   Savings Associations as defined in Section 3(b)
                       of the Federal Deposit Insurance Act;



Schedule 13G
CUSIP No. 015351109                                              Page 28 of 42

             (i) [ ]   Church Plan that is excluded from the definition
                       of an investment company under Section 3(c)(14)
                       of the Investment Company Act of 1940;

             (j) [ ]   Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

ITEM 4.   OWNERSHIP.

      The Principals may be deemed to beneficially own an aggregate of
1,804,146 shares as a result of their voting and dispositive power over the
1,804,146 shares beneficially owned by DKP, DKIP, DKIL, Serena, CO, DKHF and
DKHI.

      DKIA may be deemed to beneficially own the 345,525 shares beneficially
owned by DKIL and the 9,930 shares beneficially owned by Serena as a result of
its voting and dispositive power over those shares. DKAI may be deemed to
beneficially own the 226,517 shares beneficially owned by DKIP as a result of
its voting and dispositive power over those shares. MHD may be deemed to
beneficially own the 134,915 shares beneficially owned by DKP as a result of its
voting and dispositive power over those shares. DKG may be deemed to
beneficially own the 465,022 shares beneficially owned by DKHF as a result of
its voting and dispositive power over those shares. DKMP and DKS may be deemed
to beneficially own the 599,933 shares beneficially owned by DKHI as a result of
their voting and dispositive power over those shares.

      A. DKP

         (a) Amount beneficially owned: 134,915

         (b) Percent of class: 0.4%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 134,915

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     134,915

      B. DKIP

         (a) Amount beneficially owned: 226,517

         (b) Percent of class: 0.6%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 226,517




Schedule 13G
CUSIP No. 015351109                                              Page 29 of 42

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     226,517

      C. CO

         (a) Amount beneficially owned: 22,304

         (b) Percent of class: 0.1%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 22,304

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     22,304

      D. DKIL

         (a) Amount beneficially owned: 345,525

         (b) Percent of class: 1.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 345,525

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     345,525

      E. Serena

         (a) Amount beneficially owned: 9,930

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 9,930

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     9,930


Schedule 13G
CUSIP No. 015351109                                              Page 30 of 42

      F. DKHF

         (a) Amount beneficially owned: 465,022

         (b) Percent of class: 1.3%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 465,022

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     465,022

      G. DKHI

         (a) Amount beneficially owned: 599,933

         (b) Percent of class: 1.7%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 599,933

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     599,933

      H. MHD

         (a) Amount beneficially owned: 134,915

         (b) Percent of class: 0.4%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 134,915

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     134,915



Schedule 13G
CUSIP No. 015351109                                              Page 31 of 42

      I. DKAI

         (a) Amount beneficially owned: 226,517

         (b) Percent of class: 0.6%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 226,517

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     226,517

      J. DKIA

         (a) Amount beneficially owned: 355,455

         (b) Percent of class: 1.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 355,455

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     355,455

      K. DKG

         (a) Amount beneficially owned: 465,022

         (b) Percent of class: 1.3%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 465,022

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     465,022



Schedule 13G
CUSIP No. 015351109                                              Page 32 of 42

      L. DKMP

         (a) Amount beneficially owned: 599,933

         (b) Percent of class: 1.7%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 599,933

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     599,933

      M. DKS

         (a) Amount beneficially owned: 599,933

         (b) Percent of class: 1.7%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 599,933

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     599,933

      N. Thomas L. Kempner, Jr.

         (a) Amount beneficially owned: 1,804,146

         (b) Percent of class: 5.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 1,804,146

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     1,804,146



Schedule 13G
CUSIP No. 015351109                                              Page 33 of 42

      O. Marvin H. Davidson

         (a) Amount beneficially owned: 1,804,146

         (b) Percent of class: 5.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 1,804,146

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     1,804,146

      P. Stephen M. Dowicz

         (a) Amount beneficially owned: 1,804,146

         (b) Percent of class: 5.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 1,804,146

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     1,804,146

      Q. Scott E. Davidson

         (a) Amount beneficially owned: 1,804,146

         (b) Percent of class: 5.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 1,804,146

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     1,804,146



Schedule 13G
CUSIP No. 015351109                                              Page 34 of 42

      R. Michael J. Leffell

         (a) Amount beneficially owned: 1,804,146

         (b) Percent of class: 5.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 1,804,146

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     1,804,146

      S. Timothy I. Levart

         (a) Amount beneficially owned: 1,804,146

         (b) Percent of class: 5.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 1,804,146

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     1,804,146

      T. Robert J. Brivio, Jr.

         (a) Amount beneficially owned: 1,804,146

         (b) Percent of class: 5.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 1,804,146

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     1,804,146



Schedule 13G
CUSIP No. 015351109                                              Page 35 of 42

      U. Eric P. Epstein

         (a) Amount beneficially owned: 1,804,146

         (b) Percent of class: 5.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 1,804,146

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     1,804,146

      V. Anthony A. Yoseloff

         (a) Amount beneficially owned: 1,804,146

         (b) Percent of class: 5.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 1,804,146

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     1,804,146

      W. Avram Z. Friedman

         (a) Amount beneficially owned: 1,804,146

         (b) Percent of class: 5.0%

         (c) Number of shares as to which such person has:

             (i)   sole power to vote or to direct the vote: 0

             (ii)  shared power to vote or to direct the vote: 1,804,146

             (iii) sole power to dispose or to direct the disposition: 0

             (iv)  shared power to dispose or to direct the disposition:
                     1,804,146



Schedule 13G
CUSIP No. 015351109                                              Page 36 of 42



ITEM 5.      OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.

             Not applicable.

ITEM 6.      OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.

      The partners, members or stockholders of each of the Reporting Persons,
including the Principals, have the right to participate in the receipt of
dividends from, or proceeds from the sale of, the securities held for the
account of such Reporting Person in accordance with their ownership interests in
such Reporting Person. The Reporting Persons disclaim all beneficial ownership
as affiliates of a registered investment adviser, and, in any case, disclaim
beneficial ownership except as to the extent of their pecuniary interest in the
shares. The Reporting Persons have elected to file Schedule 13G although such
filing may not be required under the Act.

ITEM 7.      IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH
             ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT
             HOLDING COMPANY.

             Not applicable.

ITEM 8.      IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.

             See Item 4.

ITEM 9.      NOTICE OF DISSOLUTION OF GROUP.

             Not applicable.

ITEM 10.     CERTIFICATION.  (if filing pursuant to Rule 13d-1(c))

       Each of the Reporting Persons hereby makes the following certification:

       By signing below we certify that, to the best of our knowledge and
belief, the securities referred to above 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.






Schedule 13G
CUSIP No. 015351109                                              Page 37 of 42


                                   SIGNATURES

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

DATED:  March 28, 2007           DAVIDSON KEMPNER PARTNERS
                                 By: MHD Management Co.,
                                 its General Partner

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Managing Partner

                                 DAVIDSON KEMPNER INSTITUTIONAL
                                 PARTNERS, L.P.
                                 By: Davidson Kempner Advisers Inc.,
                                 its General Partner

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: President

                                 M.H. DAVIDSON & CO.

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Managing Partner

                                 DAVIDSON KEMPNER INTERNATIONAL,
                                 LTD.
                                 By: Davidson Kempner International Advisors,
                                 L.L.C.,
                                 its Investment Manager

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member

                                 SERENA LIMITED
                                 By: Davidson Kempner International Advisors,
                                 L.L.C.,
                                 its Investment Manager

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member



Schedule 13G
CUSIP No. 015351109                                              Page 38 of 42


                                 DAVIDSON KEMPNER HEALTHCARE
                                 FUND LP
                                 By:  DK Group LLC,
                                 its General Partner

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member

                                 DAVIDSON KEMPNER HEALTHCARE
                                 INTERNATIONAL LTD.
                                 By:  DK Management Partners LP,
                                 its Investment Manager
                                 By:  DK Stillwater GP LLC, its general partner

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member

                                 MHD MANAGEMENT CO.

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Managing Partner

                                 DAVIDSON KEMPNER ADVISERS INC.

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: President

                                 DAVIDSON KEMPNER INTERNATIONAL
                                 ADVISORS, L.L.C.

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member

                                 DK GROUP LLC

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member




Schedule 13G
CUSIP No. 015351109                                              Page 39 of 42


                                 DK MANAGEMENT PARTNERS LP
                                 By:  DK Stillwater GP LLC, its general partner

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member

                                 DK STILLWATER GP LLC

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Thomas L. Kempner, Jr.

                                 /s/ Marvin H. Davidson
                                 --------------------------------
                                 Marvin H. Davidson

                                 /s/ Stephen M. Dowicz
                                 --------------------------------
                                 Stephen M. Dowicz

                                 /s/ Scott E. Davidson
                                 --------------------------------
                                 Scott E. Davidson

                                 /s/ Michael J. Leffell
                                 --------------------------------
                                 Michael J. Leffell

                                 /s/ Timothy I. Levart
                                 --------------------------------
                                 Timothy I. Levart

                                 /s/ Robert J. Brivio, Jr.
                                 --------------------------------
                                 Robert J. Brivio, Jr.

                                 /s/ Eric P. Epstein
                                 --------------------------------
                                 Eric P. Epstein

                                 /s/ Anthony A. Yoseloff
                                 --------------------------------
                                 Anthony A. Yoseloff

                                 /s/ Avram Z. Friedman
                                 --------------------------------
                                 Avram Z. Friedman





Schedule 13G
CUSIP No. 015351109                                              Page 40 of 42



                                    EXHIBIT 1

                           JOINT ACQUISITION STATEMENT

                            PURSUANT TO RULE 13d-1(k)

      The undersigned acknowledge and agree that the foregoing statement on
Schedule 13G is filed on behalf of each of the undersigned and that all
subsequent amendments to this statement on Schedule 13G, shall be filed on
behalf of each of the undersigned without the necessity of filing additional
joint acquisition statements. The undersigned acknowledge that each shall be
responsible for the timely filing of such amendments, and for the completeness
and accuracy of the information concerning him or it contained therein, but
shall not be responsible for the completeness and accuracy of the information
concerning the others, except to the extent that he or it knows or has reason to
believe that such information is inaccurate.

DATED:  March 28, 2007           DAVIDSON KEMPNER PARTNERS
                                 By: MHD Management Co.,
                                 its General Partner

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Managing Partner

                                 DAVIDSON KEMPNER INSTITUTIONAL
                                 PARTNERS, L.P.
                                 By: Davidson Kempner Advisers Inc.,
                                 its General Partner

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: President

                                 M.H. DAVIDSON & CO.

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Managing Partner

                                 DAVIDSON KEMPNER INTERNATIONAL,
                                 LTD.
                                 By: Davidson Kempner International Advisors,
                                 L.L.C.,
                                 its Investment Manager

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member




Schedule 13G
CUSIP No. 015351109                                              Page 41 of 42


                                 SERENA LIMITED
                                 By: Davidson Kempner International Advisors,
                                 L.L.C.,
                                 its Investment Manager

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member


                                 DAVIDSON KEMPNER HEALTHCARE
                                 FUND LP
                                 By:  DK Group LLC,
                                 its General Partner

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member

                                 DAVIDSON KEMPNER HEALTHCARE
                                 INTERNATIONAL LTD.
                                 By:  DK Management Partners LP,
                                 its Investment Manager
                                 By:  DK Stillwater GP LLC, its general partner

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member

                                 MHD MANAGEMENT CO.

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Managing Partner

                                 DAVIDSON KEMPNER ADVISERS INC.

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: President

                                 DAVIDSON KEMPNER INTERNATIONAL
                                 ADVISORS, L.L.C.

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member




Schedule 13G
CUSIP No. 015351109                                              Page 42 of 42


                                 DK GROUP LLC

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member


                                 DK MANAGEMENT PARTNERS LP
                                 By:  DK Stillwater GP LLC, its general partner

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member

                                 DK STILLWATER GP LLC

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Name:  Thomas L. Kempner, Jr.
                                 Title: Executive Managing Member

                                 /s/ Thomas L. Kempner, Jr.
                                 --------------------------------
                                 Thomas L. Kempner, Jr.

                                 /s/ Marvin H. Davidson
                                 --------------------------------
                                 Marvin H. Davidson

                                 /s/ Stephen M. Dowicz
                                 --------------------------------
                                 Stephen M. Dowicz

                                 /s/ Scott E. Davidson
                                 --------------------------------
                                 Scott E. Davidson

                                 /s/ Michael J. Leffell
                                 --------------------------------
                                 Michael J. Leffell

                                 /s/ Timothy I. Levart
                                 --------------------------------
                                 Timothy I. Levart

                                 /s/ Robert J. Brivio, Jr.
                                 --------------------------------
                                 Robert J. Brivio, Jr.

                                 /s/ Eric P. Epstein
                                 --------------------------------
                                 Eric P. Epstein

                                 /s/ Anthony A. Yoseloff
                                 --------------------------------
                                 Anthony A. Yoseloff

                                 /s/ Avram Z. Friedman
                                 --------------------------------
                                 Avram Z. Friedman