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Exhibit 10.72

SECOND AMENDMENT TO LEASE

        THIS SECOND AMENDMENT TO LEASE (this "Amendment") dated as of
November 7, 2001, is entered into by and between ABGENIX, INC., a Delaware
corporation ("Tenant"), and ARDENWOOD CORPORATE PARK ASSOCIATES, a California
limited partnership ("Landlord").

RECITALS

        A.    Landlord and Tenant have entered into that certain Lease Between
Abgenix, Inc. and Ardenwood Corporate Park Associates (Kaiser Drive
Build-to-Suit) dated as of May 19, 2000, as amended by the First Amendment to
Lease dated as of August 31, 2001 (as so amended, the "Lease"), pursuant to
which Tenant leases from Landlord certain premises located at 6755 Kaiser Drive,
Fremont, California and commonly known as "Building 3" (as more particularly
described in the Lease, the "Premises"). Initially capitalized terms not
otherwise defined herein shall have the meanings given to such terms in the
Lease.

        B.    Tenant has elected to exercise its right to order the Building
Shell Modifications described in Section 5(A) of the Lease.

        C.    Pursuant to Section 4(C) of the Lease, Tenant has heretofore
deposited with Landlord a letter of credit (the "Letter of Credit") in the
amount of $2,000,000. In consideration of certain modifications requested by
Tenant with respect to the Building Shell, Tenant has agreed to increase the
amount of the Letter of Credit by $500,000 upon the terms and conditions set
forth below.

        NOW THEREFORE, in consideration of the mutual promises contained herein
and for other good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, Landlord and Tenant hereby agree as follows:

        1.    Building Shell Modifications.    Landlord and Tenant hereby agree
that Landlord shall perform the Building Shell Modifications described in
Section 5(A) of the Lease, subject to Tenant's approval of the plans and
specifications with respect thereto in accordance with the Lease.

        2.    Letter of Credit.    As of the date of this Amendment, the amount
of the Letter of Credit pursuant to Section 4(C) of the Lease shall be amended
to be $2,500,000. On or before December 2, 2001, Tenant shall deliver to
Landlord an amendment to the Letter of Credit increasing the amount of the
Letter of Credit to $2,500,000 (the "LC Amendment"). From and after the date
hereof, all references in the Lease to the Letter of Credit shall mean and refer
to the Letter of Credit as amended by the LC Amendment.

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        3.    Shell Modification Payment.    Landlord hereby acknowledges that
on or prior to the date hereof, Tenant has paid to Landlord, pursuant to
Section 5(A) of the Lease, the entire cost of the Building Shell Modifications
in the amount of $290,770 (the "Payment Amount"). Landlord agrees that the
Payment Amount represents payment in full by Tenant for the Building Shell
Modifications and that Tenant shall not be responsible for any costs or expenses
incurred by Landlord with respect to the Building Shell Modifications in excess
of the Payment Amount.

        4.    No Other Changes.    Except as modified by this Amendment, all of
the terms and provisions of the Lease shall remain in full force and effect and
unmodified with respect to the Premises.

        5.    Counterparts.    This Amendment may be executed in any number of
counterparts, each of which shall be deemed an original, but all of which taken
together shall constitute one and the same instrument.

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        IN WITNESS WHEREOF, the parties have executed this Amendment as of the
date first above written.

    TENANT:
 
 
ABGENIX, INC.,
a Delaware corporation
 
 
By:
 
/s/  KURT LEUTZINGER      

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    Its:   Chief Financial Officer

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LANDLORD:
 
 
ARDENWOOD CORPORATE PARK ASSOCIATES,
a California limited partnership
 
 
By:
 
/s/  JOHN MICHAEL SOBRATO      

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    Its:   General Partner

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Exhibit 10.72

RECITALS