SEC Filing | Alexion Pharmaceuticals, Inc.

View:

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