Exhibit 10.71

FIRST AMENDMENT TO LEASE
(6755 Kaiser Drive)

This First Amendment to Lease ("First Amendment") is made as of the 31st day of August, 2001 by and between Ardenwood Corporate Park Associates, a California
Limited Partnership, having an address at 10600 N. De Anza Blvd., Suite 200, Cupertino, California 95014 ("Landlord") and Abgenix, Inc., a Delaware corporation, whose address 7601 Dumbarton Circle,
Fremont California, 94555 ("Tenant").

WITNESSETH

WHEREAS,Landlord and Tenant entered into a lease dated May 19, 2000 ("Lease") for a building of approximately
100,000 rentable square feet ("Building") to be constructed at 6755 Kaiser Drive in Fremont, California ("Premises"), adjacent to a building at 6701 Kaiser Drive ("6701 Premises") currently leased by
Tenant from Landlord pursuant to a lease between the parties dated February 24, 2000 ("6701 Premises Lease");

WHEREAS,effective the date of this First Amendment, Landlord and Tenant wish to modify the Lease to: (i) provide for construction of a
2-story building link totaling 15,522 rentable square feet ("Link Structure") to connect the 6701 Premises and the Premises; (ii) specify the terms and conditions under which Tenant shall lease the
Link Structure; and (iii) provide for Tenant's granting to Landlord of real estate financing for the Premises and Link Structure in the amount of $16,750,000.00 ("Loan") evidenced by a promissory
note, deed of trust, assignment of leases, assignment of contracts, loan agreement and other loan documents (collectively "Loan Documents") between the parties;

WHEREAS,Landlord and CPTFNC Funding, LLC (the "First Lender") and Tenant have agreed to enter into an Intercreditor Agreement dated as of
the date hereof (the "Intercreditor Agreement") and Landlord, Tenant and First Lender have agreed to enter into a subordination, nondisturbance and attornment agreement dated as of August 31, 2001
(the "SNDA") with respect to the Lease;

WHEREAS,simultaneously herewith, the parties have agreed to enter into a Standstill Agreement with respect to the Lease and the Loan
Documents (the "Standstill Agreement").

NOW, THEREFORE,in order to effect the intent of the parties as set forth above and for good and valuable consideration exchanged between
the parties, the Lease is amended as follows:

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IN WITNESS WHEREOF,the parties hereto have set their hands to this First Amendment as of the day and date first above written.

|LandlordArdenwood Corporate Park Associates,
a California Limited Partnership |  | TenantAbgenix, Inc.,
a Delaware Corporation
|----------------------------------------------------------------------------- |  | -------------------------------------------
|By:                                                                           |  | /s/JOHN MICHAEL SOBRATO                    
|                                                                              |  | Its:                                       

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Exhibit A
Link Shell Plans and Specifications

Ardenwood Phase III Link
6753 Kaiser Drive.
Fremont, California

|Drawing List:  |  |                                                     
|-------------- |  | ----------------------------------------------------
|Architectural: |  |                                                     
|Cover Sheet    |  |                                                     
|A0.1           |  | Project Information and Drawing Index               
|A1.0           |  | Site Plan                                           
|A2.0           |  | First Level Plan                                    
|A2.1           |  | Second Level Plan                                   
|A2.2           |  | Roof Plan                                           
|A2.3           |  | Entry Plans and Elevations                          
|A3.0           |  | Exterior Elevations                                 
|A4.0           |  | Building Sections                                   
|A4.1           |  | Building Wall Sections                              
|A7.0           |  | Door Schedule                                       
|A8.0           |  | Details                                             
|A8.1           |  | Details                                             
|A8.2           |  | Details                                             
|A8.3           |  | Details                                             
|A10.0          |  | Specifications                                      
|A10.1          |  | Title 24, Non Residential Accessibility Requirements
|A10.2          |  | Title 24, Energy Compliance Requirements            
|A10.3          |  | Title 24, Energy Compliance Requirements            
|Civil          |  |                                                     
|C-1            |  | Topographic                                         
|C-2            |  | Demolition Plan                                     
|C-3            |  | Grading and Drainage Plan                           
|C-4            |  | Utility Plan                                        
|C-5            |  | Erosion Control Plan                                
|C-6            |  | Horizontal Control Plan                             
|C-7            |  | Details                                             
|ENV-1          |  | Building Envelope Compliance                        
|Landscape      |  |                                                     
|L-1.0          |  | Notes and Legends                                   
|L-2.1          |  | Layout and Grading Plan                             
|L-2.2          |  | Planting Plan                                       
|L-3.0          |  | Irrigation Notes & Details                          
|L-3.1          |  | Irrigation Plan                                     
|L-4.1          |  | Construction Details                                
|L-4.2          |  | Construction Details                                

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|Structural Continued |  |                                    
|-------------------- |  | -----------------------------------
|S-0.1                |  | General Notes                      
|S-1.0                |  | Foundation Plan                    
|S-2.0                |  | Second Floor Framing Plan          
|S-3.0                |  | Roof Framing Plan                  
|S-4.0                |  | Moment Frame Elevations & Schedules
|S-5.0                |  | Floor Framing Details              
|S-5.1                |  | Floor Framing Details              
|S-6.0                |  | Framing Details                    
|S-6.1                |  | Framing Details                    
|S-6.2                |  | Framing Details                    
|S-6.3                |  | Framing Details                    

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Exhibit B
Link Tenant Improvement Plans and Specifications

|DRAWING INDEX
|-------------
|ARCHITECTURAL
|A0           
|A0.1         
|A0.2         
|A1.0         
|A2.0D        
|A2.1         
|A2.1F        
|A2.1Q        
|A2.1R        
|A2.2         
|A2.2F        
|A2.2R        
|A2.3         
|A3.1         
|A3.2         
|A3.3         
|A4.1         
|A5.1         
|A6.1         
|A7.1         
|A8.1         
|A8.2         
|A8.3         
|A8.4         
|A8.5         

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Exhibit C
PROFORMA

SCHEDULE C
LEGAL DESCRIPTION

All that certain real property situate in the City of Fremont, County of Alameda, State of California, described as follows:

PARCEL
ONE:

All
that portion of land designated and delineated as "Merged Lot A" in the Declaration of Merger filed for record in the office of the Recorder of the County of Alameda on
                        under Recorder's Serials
No.             Official Records and being more particularly described as follows;

Being
all of Lot 9 and Lot 10-Lot Line Adjustment 2000-10, as said lots are described in the Grant Deed recorded January 25, 2001, as instrument
number 01-027935, Alameda County Records, more particularly described as follows:

Beginning
at the easterly corner of said Lot 10, said corner being a point in the northwesterly right of way line of Kaiser Drive, 100 feet in width, as said drive is shown
on Parcel Map 4118, filed March 30, 1984 in Book 143 of Maps, at pages 44 through 48, Alameda County Records,

Thence
along the southeasterly lien of said Lot 10, and along the southwesterly line of said Lot 9, said lines being also the northwesterly right of way lien of Kaiser
Drive, the following three courses:

Thence
along the southwesterly line of said Lot 9, North 21°53'25" West, 600.09 feet to the westerly corner of said Lot 9;

Thence
along the northwesterly line of said Lot 9 and along the northwesterly line of said Lot 10, North 65°05'35" East, 689.97 feet to the northerly
corner of said Lot 10;

Thence
along the northeasterly line of said Lot 10, South 26°00'00" East, 625.86 feet to the point of beginning.

PARCEL
TWO:

A
non-exclusive easement for Ingress and Egress over the following described property;

Being
a portion of Lot 11, as said Lot is shown upon that certain Parcel map 4118, filed in Book 143 of Maps at pages 44-48, inclusive, Alameda County
Records;

Being
a strip of land 22.50 feet in width, the westerly line of said strip described as follows:

Beginning
at the southwest corner of said Lot 11, said point also being on the northerly right of way line of Kaiser Drive, (108 feet wide), as shown upon said map; thence
departing said right of way line, and along the westerly line of said Lot 11, North 26°02'11" West, 72.00 feet to the terminus of said westerly line being described.

ARB
No: -0-
APN No: 543-0439-047-01; 543-0439-048-02

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Schedule 1

|Project   |  | Ardenwood Link Building        |  | Date: August 28, 2001
|--------- |  | ------------------------------ |  | ---------------------
|Location: |  | 6753 Kaiser Drive, Fremont, CA |  |                      
|Size:     |  | 15522 square feet              |  |                      
|Job #30L  |  |                                |  |                      

BUDGETLINK SHELL HARD COSTS

|                                               |  | DESCRIPTION                                                                     |  | SOBRATO |                       | Comments
|---------------------------------------------- |  | ------------------------------------------------------------------------------- |  | ------- | --------------------- | --------
|1                                              |  | Surveying and Staking                                                           |  |         | 10,000                |         
|2                                              |  | Grading and Paving                                                              |  |         | 54,153                |         
|3                                              |  | Striping                                                                        |  |         | 800                   |         
|4                                              |  | Site Utilities
Asphalt Patching
Allowance to use 2nd Bidder                     |  |         | 100,320
10,000
10,000 |         
|5                                              |  | Fountain Mechanical                                                             |  |         | 54,985                |         
|6                                              |  | Site Concrete                                                                   |  |         | 83,800                |         
|7                                              |  | Building Concrete                                                               |  |         | 141,953               |         
|8                                              |  | GFRC                                                                            |  |         | 40,950                |         
|9                                              |  | Steel/Misc. Metals                                                              |  |         | 546,495               |         
|10                                             |  | Metal Deck                                                                      |  |         | 36,374                |         
|11                                             |  | Expansion Joint                                                                 |  |         | 48,659                |         
|12                                             |  | Insulation                                                                      |  |         | 5,500                 |         
|13                                             |  | Built-up Roof and Waterproofing                                                 |  |         | 31,135                |         
|14                                             |  | Arch, Sheet Metal                                                               |  |         | 8,344                 |         
|15                                             |  | Sealants and Caulking                                                           |  |         | 2,500                 |         
|16                                             |  | Glass, Glazing, Aluminum Rod                                                    |  |         | 328,852               |         
|17                                             |  | Studs and Some Framing/Rough Carp.                                              |  |         | 45,860                |         
|18                                             |  | Painting (Exterior)
Paint Touch-up                                              |  |         | 6,875
1,000           |         
|19                                             |  | Fire Sprinklers                                                                 |  |         | 20,440                |         
|20                                             |  | Plumbing                                                                        |  |         | 29,484                |         
|21                                             |  | Site Lighting and Electrical                                                    |  |         | 1,020                 |         
|                                               |  | SUBTOTAL                                                                        |  | $       | 1,628,717             |         
|                                               |  | CONTINGENCY (5%)                                                                |  | $       | 81,336                |         
|                                               |  | Subtotal                                                                        |  | $       | 1,708,053             |         
|                                               |  | FEE AND GC: (5.5%)                                                              |  | $       | 83,843                |         
|                                               |  | PROJECT TOTAL COST                                                              |  |         | 1,801,996             |         
|Project SummaryGuaranteed Maximum Price (GMP) |  |                                                                                 |  |         |                      
|                                               |  | Sobrato pays last                                                               |  | $       | 776,000               |         
|                                               |  | Abgenix pays next                                                               |  | $       | 1,025,996             |         
|                                               |  | Sobrato pays anything over the GMP of                                           |  | $       | 1,801,898             |         
|                                               |  | In addition, beyond the first $778K, Sobrato pays for all Link Shelf Soft Costs

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