Exhibit 1.1
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JOINT FILING AGREEMENT
The undersigned hereby agree that the Statement on this Schedule 13G/A, dated
May 1, 2003, (the "Schedule 13G/A"), with respect to the Common Stock, par value
$0.0001 per share, of Alexion Pharmaceuticals, Inc. is filed on behalf of each
of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under
the Securities and Exchange Act of 1934, as amended, and that this Agreement
shall be included as an Exhibit to this Schedule 13G/A. Each of the undersigned
agrees to be responsible for the timely filing of the Schedule 13G/A, and for
the completeness and accuracy of the information concerning itself contained
therein. This Agreement may be executed in any number of counterparts, all of
which taken together shall constitute one and the same instrument.
IN WITNESS WHEREOF, the undersigned have executed this Agreement as of
the 1st day of May, 2003.
OrbiMed Advisors LLC
By: /s/ Xxxxxx X. Xxxxx
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Name: Xxxxxx X. Xxxxx
Title: Managing Member
OrbiMed Capital LLC
By: /s/ Xxxxxx X. Xxxxx
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Name: Xxxxxx X. Xxxxx
Title: Managing Member
By: /s/ Xxxxxx X. Xxxxx
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Name: Xxxxxx X. Xxxxx
