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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:

1.The definition of the Premises as set forth in Lease paragraph 2 is amended to
include the Link Structure.

2.Concurrently with execution of this First Amendment, the parties have executed
the Loan Documents which provides for Tenant's commitment to fund the Loan to
Landlord for the purposes of financing the Premises and the Link Structure. The
effectiveness of this First Amendment is subject to and conditioned upon (a)
Landlord and Tenant executing the Loan Documents and the Standstill Agreement;
(b) Landlord, Tenant and First Lender executing the Intercreditor Agreement and
the SNDA; (c) First Lender consenting in writing to this First Amendment; (d)
Landlord and Tenant executing a First Amendment to the 6701 Premises Lease in
form acceptable to Landlord and Tenant (the "6701 Lease Amendment"); and (e)
First Lender consenting in writing to the 6701 Lease Amendment.

3.The shell of the Link Structure ("Link Shell") shall be Landlord's
responsibility and shall be constructed by independent contractors employed by
and under the supervision of General Contractor in accordance with plans and
specifications prepared by Arc-Tec Associates dated March 7, 2001 ("Link Shell
Plans and Specifications"), attached by reference as Exhibit "A". Subject to
Force Majeure events, Landlord shall complete construction of the Link Shell by
March 31, 2002. The cost of construction of the Link Shell pursuant to the Link
Shell Plans and Specifications are itemized on the budget attached hereto as
Schedule 1 and are referred to herein as the "Link Shell Hard Costs." Tenant's
obligation for payment of the Link Shell Hard Costs shall

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not exceed the "Maximum Link Shell Hard Costs" set forth on Schedule 1. In
addition to Landlord's obligation to pay to Tenant the Link Structure Allowance
(as defined in paragraph 5 below), Landlord shall be responsible for any Link
Shell Hard Costs in excess of the Maximum Link Shell Hard Costs ("Landlord
Excess Hard Costs"). Notwithstanding anything in the Lease to the contrary, the
parties agree that to the extent reasonably possible, the same contractors with
which General Contractor has already committed to construct the Building and
Premises shall also be hired to construct the Link Shell. The parties
acknowledge that Tenant may elect to have construction of the Link Tenant
Improvements (as defined in Section 4 below) completed at a later date than the
Link Shell. The parties acknowledge that Tenant has requested and Landlord has
agreed to defer Landlord's completion of slurry, striping and signage in
associated parking lot areas and landscape pertaining to the Building and the
Link Shell ("Deferred Landlord's Work"). Landlord agrees to complete the
Deferred Landlord's Work by December 1, 2002 or such later date as Tenant may
direct in writing.

4.Tenant, at Tenant's sole cost and expense, has retained Dowler Gruman
Architects which has prepared the plans and outline specifications attached as
Exhibit B ("Link Tenant Improvement Plans and Specifications") with respect to
Tenant's construction of improvements to the Link Structure ("Link Tenant
Improvements") necessary for Tenant's use and occupancy. Landlord has reviewed
and approved the Link Tenant Improvement Plans and Specifications. The Link
Tenant Improvement Plans and Specifications provide for a minimum build-out in
all areas of the Link Structure consisting of: (i) fire sprinklers, (ii) floor
coverings, (iii) t-bar suspended ceiling (iv) distribution of the HVAC system,
(v) adequate lighting, and (vi) any other work necessary to obtain an
unconditional certificate of occupancy from the city of Fremont. Tenant's
Contractor shall use union labor. Tenant shall contract directly with and shall
cause Tenant's Contractor to construct the Link Tenant Improvements
substantially in accordance with all Link Tenant Improvement Plans and
Specifications. Landlord agrees to permit Tenant's Contractor access to the Link
Structure as soon as reasonably practicable in order to commence construction of
the Link Tenant Improvements provided such access does not unreasonably
interfere with General Contractor's construction of the Link Shell. Tenant shall
use commercially reasonable efforts to obtain a building permit from the City of
Fremont as soon as reasonably practicable and thereafter diligently supervise
the construction of Link Tenant Improvements until they are substantially
complete as hereinafter defined. The Link Tenant Improvements shall be deemed
substantially complete ("Substantially Complete" or "Substantial Completion")
when the Link Tenant Improvements have been substantially completed other than
for minor punchlist items in accordance with the Link Tenant Improvement Plans
and Specifications, as evidenced by the completion of a final inspection or the
issuance of a certificate of occupancy or its equivalent by the appropriate
governmental authority, whichever is applicable. Installation of Tenant's data
and phone cabling or furniture shall not be required in order to deem the Link
Tenant Improvements Substantially Complete. Once complete, the Link Tenant
Improvements shall be considered Tenant Improvements and subject to all
applicable provisions in the Lease regarding Tenant Improvements.

5.All design and architectural costs, permit fees, and other costs imposed by
governmental authorities related to the Link Shell ("Link Shell Soft Costs")
shall be paid by Landlord. In addition, Landlord shall also pay to Tenant
$776,000.00 ("Link Structure Allowance") towards the Link Shell Hard Costs
payable by Tenant. Upon Landlord's completion of the Link Shell (other than the
Deferred Landlord's Work), Landlord shall deliver to Tenant an invoice
("Invoice") for the amount of the actual Link Shell Hard Costs including the
General Contractor's Fee defined in paragraph 6 hereof (not to exceed the
Maximum Link Shell Hard Costs) ("Invoiced Amount"). Within ten (10) days
following receipt of the Invoice, Tenant shall pay to Landlord the Invoiced
Amount. Concurrently therewith, Landlord shall pay the Link Structure Allowance
to Tenant or,

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alternatively, if Landlord and Tenant mutually agree, Tenant may offset the
amount of the Link Structure Allowance from the Invoiced Amount paid by Tenant
to Landlord.

6.Other than the Link Shell Soft Costs and Link Structure Allowance paid by
Landlord pursuant to paragraph 5 above, and any Landlord Excess Hard Costs for
which Landlord is responsible pursuant to paragraph 3 above, Tenant shall pay
all costs associated with construction of the Link Structure including, but not
limited to the following: (i) Link Shell Hard Costs up to the Maximum Link Shell
Hard Costs; (ii) construction costs of the Link Tenant Improvements, (iii) all
permit fees, construction taxes or other costs imposed by governmental
authorities related to the Link Tenant Improvements, and (iv) a fee equal to
5.5% of the Link Shell Hard Costs (up to the Maximum Link Shell Hard Costs) to
be paid to General Contractor to cover all of the following: construction
supervision and administration, temporary on-site facilities, home office
administration, supervision, and coordination and construction profit ("General
Contractor's Fee").

7.In order to facilitate construction and financing of the Premises, Tenant
consents to the merging of the two parcels on which the Premises and the 6701
Premises are situated (APN 543-439-048-01 and 543-439-047-02 respectively) into
one parcel totaling 10.082 acres, as shown on the attached Exhibit "C".
Landlord, at its sole cost and expense, shall cause the merger of the two
parcels to occur prior to the Initial Disbursement of the Loan.

8.Base Monthly Rent for the Link Structure shall at all times be at the same
rate as the Building as set forth in Section 4.A. of the Lease; provided,
however, that Base Monthly Rent for the Link Structure portion of the Premises
shall not commence until Landlord's Substantial Completion of the Link
Structure. With respect to the rent commencement date for the Building, the
parties acknowledge that construction of the Link Structure will delay
Landlord's completion of the Building and Premises. Such delay does not affect
the Lease and the parties acknowledge that the Lease has commenced and that the
rent commencement date was April 1, 2001.

9.The following sentence shall be added to the end of Section 14B of the Lease.

Notwithstanding the foregoing, in the event that damage or destruction occurs in
the last eighteen (18) months of the Lease Term but prior to the date which is
twelve (12) months prior to the expiration of the Lease Term and in the event
Landlord elects to terminate this Lease pursuant to clause (iv) above, Tenant
may void Landlord's termination notice by exercising in writing any next
immediately succeeding Option to extend the Term of the Lease and the Term of
the 6701 Premises Lease pursuant to Section 18 of this Lease, provided Tenant
notifies Landlord of its exercise of said Option(s) within ten (10) days
following receipt of Landlord's termination notice. In the event Tenant timely
exercises its next succeeding Option to extend the Term of this Lease and the
Term of the 6701 Premises Lease, then Landlord's termination notice shall be
void and Landlord shall complete the repair or restoration of the Premises in
accordance with the terms of this Lease.

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10.A new Section 18 E shall be added to the Lease as follows:

E.Exercise of Option to Extend Tenant's Lease for 6701 Kaiser Drive, Fremont

Tenant leases from Landlord the building adjacent to the Premises, which
building is located at 6701 Kaiser Drive (the "6701 Premises") pursuant to a
lease between Landlord and Tenant dated February 24, 2000 ("6701 Premises
Leases"). The 6701 Premises are connected to the Premises by the portion of the
Premises referred to as the Link Structure. Accordingly, it shall be a further
condition to Tenant's exercise of its Option(s) to extend the Term of this Lease
pursuant to this Section 18, that Tenant simultaneously exercise its Option(s)
to extend the Term of the 6701 Premises Lease in accordance with the provisions
of Section 18 of the 6701 Premises Lease. (All terms and conditions of
Section 18 of the 6701 Premises Lease shall apply to Tenant's exercise of its
Option(s) to extend the Term of the 6701 Premises Lease.)

11.Tenant's breach of its obligations under Section 6.2 of the Standstill
Agreement shall constitute a default under the Lease. Accordingly, the following
clause (viii) is added to the end of the first paragraph of Section 13 of the
Lease:

or (viii) Tenant's breach of its obligations under Section 6.2 of that certain
Standstill Agreement executed by Landlord as Borrower and Tenant as Lender dated
as of August 31, 2001.

12.All defined terms shall have the same meanings as in the Lease, except as
otherwise stated in this First Amendment.

13.Except as hereby amended, the Lease and all of the terms, covenants and
conditions thereof shall remain unmodified and in full force and effect. In the
event of conflict or inconsistency between the terms and provisions of this
First Amendment and the terms and provisions of the Lease, the terms and
provisions of this First Amendment shall prevail.

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

Landlord
Ardenwood Corporate Park Associates,
a California Limited Partnership   Tenant
Abgenix, Inc.,
a Delaware Corporation
By:
 
/s/  JOHN MICHAEL SOBRATO      

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By:
 
/s/ KURT LEUTZINGER

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    Its: General Partner       Its: CFO

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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
 
 
 
Delta 3—5/1/01 A0.1   Project Information and Drawing Index   Delta 3—5/1/01
A1.0   Site Plan   Delta 3—5/1/01 A2.0   First Level Plan   Delta 3—5/1/01 A2.1
  Second Level Plan   Delta 3—5/1/01 A2.2   Roof Plan   Delta 1—3/14/01 A2.3  
Entry Plans and Elevations   Delta 2—4/6/01 A3.0   Exterior Elevations   Delta
2—4/6/01 A4.0   Building Sections   Delta 2—4/6/01 A4.1   Building Wall Sections
  Delta 3—5/1/01 A7.0   Door Schedule   Delta 2—4/6/01 A8.0   Details   Delta
3—5/1/01 A8.1   Details   Delta 2—4/6/01 A8.2   Details   Delta 3—5/1/01 A8.3  
Details   Delta 1—3/14/01 A10.0   Specifications   3/7/01 A10.1   Title 24, Non
Residential Accessibility Requirements   3/7/01 A10.2   Title 24, Energy
Compliance Requirements   3/7/01 A10.3   Title 24, Energy Compliance
Requirements   3/7/01
Civil
 
 
 
 
C-1
 
Topographic
 
Delta 3—5/1/01 C-2   Demolition Plan   Delta 3—5/1/01 C-3   Grading and Drainage
Plan   Delta 3—5/1/01 C-4   Utility Plan   Delta 3—5/1/01 C-5   Erosion Control
Plan   Delta 3—5/1/01 C-6   Horizontal Control Plan   Delta 3—5/1/01 C-7  
Details   Delta 3—5/1/01
ENV-1
 
Building Envelope Compliance
 
10/2/01
Landscape
 
 
L-1.0
 
Notes and Legends
 
Delta 3—5/1/01 L-2.1   Layout and Grading Plan   Delta 3—5/1/01 L-2.2   Planting
Plan   Delta 3—5/1/01 L-3.0   Irrigation Notes & Details   Delta 3—5/1/01 L-3.1
  Irrigation Plan   Delta 3—5/1/01 L-4.1   Construction Details   Delta 3—5/1/01
L-4.2   Construction Details   Delta 3—5/1/01

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Structural Continued
 
 
S-0.1
 
General Notes
 
Delta 3—5/1/01 S-1.0   Foundation Plan   Delta 3—5/1/01 S-2.0   Second Floor
Framing Plan   Delta 3—5/1/01 S-3.0   Roof Framing Plan   Delta 3—5/1/01 S-4.0  
Moment Frame Elevations & Schedules   Delta 3—5/1/01 S-5.0   Floor Framing
Details   Delta 3—5/1/01 S-5.1   Floor Framing Details   Delta 3—5/1/01 S-6.0  
Framing Details   Delta 3—5/1/01 S-6.1   Framing Details   Delta 3—5/1/01 S-6.2
  Framing Details   Delta 3—5/1/01 S-6.3   Framing Details   Delta 3—5/1/01

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Exhibit B
Link Tenant Improvement Plans and Specifications

DRAWING INDEX
ARCHITECTURAL
A0
 
DRAWING INDEX, PROJECT DATA, ABBREVIATIONS A0.1   OVERALL CODE COMPLIANCE
PLANS—LEVEL 1 A0.2   OVERALL CODE COMPLIANCE PLANS—LEVEL 2 A1.0   OVERALL SITE
PLAN; PARKING CALCULATION AND NOTES A2.0D   DEMOLITION FLOOR AND CEILING
PLANS—LEVELS 1 & 2 A2.1   FLOOR PLAN—LEVEL 1 A2.1F   FINISH PLAN—LEVEL 1 A2.1Q  
EQUIPMENT PLAN—LEVEL 1 A2.1R   REFLECTED CEILING PLAN—LEVEL 1 A2.2   FLOOR
PLAN—LEVEL 2 A2.2F   FINISH PLAN—LEVEL 2 A2.2R   REFLECTED CEILING PLAN—LEVEL 2
A2.3   HORIZONTAL EXIT FLOOR PLANS, SECTION AND DETAILS A3.1   DOOR, FRAME AND
WINDOW SCHEDULES; WALL TYPES A3.2   ENLARGED PLANS & ELEVATIONS; TOILET ROOMS &
SHOWERS; MOUNTING HGHT. SCHEDULE A3.3   ENLARGED PLANS, DETAILS & SECTION:
STAIRS & WH/CHRLIFT A4.1   BUILDING SECTIONS A5.1   EXTERIOR ELEVATIONS A6.1  
ROOF PLAN AND TYPICAL EXTERIOR & PENETRATION DETAILS A7.1   INTERIOR ELEVATIONS
A8.1   INTERIOR DETAILS A8.2   INTERIOR DETAILS A8.3   INTERIOR DETAILS A8.4  
INTERIOR DETAILS A8.5   INTERIOR DETAILS

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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:

1.South 64°00'00" West, 120.97 feet;

2.Southwesterly along the arc of a 946.00 foot radius, tangent curve to the
right, through a central angle of 4°00'00", an arc distance of 66.04 feet; and

3.South 68°00'00" West, 547.23 feet to the southerly corner of said Lot 9;

        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

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  SOBRATO

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  Comments

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1   Surveying and Staking     10,000   Allowance 2   Grading and Paving    
54,153   Includes costs for Lime Treatment and for Courtyard grading 3  
Striping     800     4   Site Utilities
Asphalt Patching
Allowance to use 2nd Bidder     100,320
10,000
10,000    
Allowance
Allowance 5   Fountain Mechanical     54,985   Bid - value engineer will
design/build sub for possible savings 6   Site Concrete     83,800   Obtain
additional bid 7   Building Concrete     141,953     8   GFRC     40,950     9  
Steel/Misc. Metals     546,495   Cost includes $88,000 for Courtyard Metal and
320,000 for 83 mods 10   Metal Deck     36,374     11   Expansion Joint    
48,659   Obtain additional bid 12   Insulation     5,500   Allowance 13  
Built-up Roof and Waterproofing     31,135     14   Arch, Sheet Metal     8,344
  Obtain additional bid 15   Sealants and Caulking     2,500   Allowance 16  
Glass, Glazing, Aluminum Rod     328,852   Review $50,392 alternate to modify 82
window system at 2nd floor 17   Studs and Some Framing/Rough Carp.     45,860  
  18   Painting (Exterior)
Paint Touch-up     6,875
1,000     
Allowance 19   Fire Sprinklers     20,440     20   Plumbing     29,484   Abgenix
and Dome to consider installation of sewer gut line under T 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   (Link Structure Allowance)     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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*Maximum Link Shell Hard Costs

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Exhibit 10.71