Confidential Treatment Requested As To Certain
                  Information Contained In This Exhibit

February 13, 2001

Mr. Chip Catlin
Avant Immunotherapeutics, Inc.
119 Fourth Avenue
Needham, MA  02494

RE: Amendment to the License and Royalty Agreement between Avant
Immunotherapeutics, Inc. ("Avant"), Megan Health, Inc. ("Megan") and Pfizer Inc
and its Affiliates ("Pfizer"), executed on December 1, 2000 ("Agreement")

Dear Mr. Catlin,

In accordance with recent discussions between Avant, Megan and Pfizer, we hereby
propose that, effective as of the date of your acceptance below, the License and
Royalty  Agreement  between  Megan,  Avant and  Pfizer be  amended as follows to
reflect the parties' intent regarding payments to be made under the Agreement.

SECTION 3.1: FIRST SENTENCE: "Megan" shall be replaced with "Avant" such that
the sentence reads, "Pfizer shall pay Avant a royalty based on the Net Sales of
each Product".

SECTION 3.4: FIRST SENTENCE: "Megan" shall be replaced with "Avant" such that
the sentence reads, "The Net Sales used for computing the royalties payable to
Avant by Pfizer shall be computed and paid in U.S. dollars by wire transfer."

SECTION 3.6: FIRST SENTENCE: "Megan" shall be replaced with "Avant" such that
the sentence reads, "Pfizer shall pay Avant, within sixty (60) days of the
completion of each respective event set forth below ("Event"), the payment
listed opposite that Event."

SECTION 4.1: SECOND TO LAST SENTENCE: "Megan" shall be replaced with "Avant"
such that the sentence reads, "However, *** Confidential Treatment Requested as
to this information *** of any such sums received by Pfizer, after deduction of
all costs and expenses related to such suit or settlement, including attorney's
fees paid, shall be paid to Avant."



In all other respects, the Agreement shall be in full force and effect for the
term of the Agreement. If you are in agreement, please have authorized
signatories of both Megan and Avant execute this letter below. Each party may
keep one copy for their records.

Thank you for your attention to this matter.


                                            Regards,


                                            Pfizer Inc

                                            By:
                                                --------------------------------
                                                Barrie Hesp, Vice President
                                                Strategic Alliances


ACCEPTED:

Avant Immunotherapeutics, Inc.

By:
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Title:
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Date:
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Megan Health, Inc.

By:
    ---------------------------

Title:
       ------------------------

Date:
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