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:                                                                  
| |  | Its:                                                                 
| |  |                                                                      
| |  | LANDLORD:                                                            
| |  | ARDENWOOD CORPORATE PARK ASSOCIATES,
a California limited partnership
| |  | By:                                                                  
| |  | Its:                                                                 

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