Item 8.01 Other Events.
On November 8, 2012, Alexion Pharmaceuticals, Inc. issued a press release announcing that its Board of Directors authorized the repurchase of up to $400 million of Alexion's common stock. A copy of the press release is attached as Exhibit 99.1 to this Form 8-K and incorporated herein by reference.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits 99.1 Press Release issued by Alexion Pharmaceuticals, Inc. on November 8, 2012. -------------------------------------------------------------------------------- Signature

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

Date: November 8, 2012 ALEXION PHARMACEUTICALS, INC.

By: /s/ Michael V. Greco
Name: Michael V. Greco
Title: Associate General Counsel and Corporate Secretary