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REDACTED VERSION

SUBLEASE AGREEMENT

This Sublease Agreement ("Sublease") dated as of July 24, 2000, is made between F5 Networks, Inc., a Washington corporation ("Sublandlord"), and
NeoRx Corporation Inc., a Washington corporation ("Subtenant").

RECITALS

A.  Pursuant to the Amended and Restated Office Lease Agreement dated April 3, 2000 between 401 Elliott West, LLC, a Washington limited
liability corporation, as lessor ("Landlord") and Sublandlord as lessee (together with all modifications, amendments, riders and exhibits thereto, the "Master Lease"), a copy of which is attached
hereto as Exhibit A, Landlord leased to Sublandlord approximately 110,111 rentable square feet of space in Building 3 located at 401 Elliott Avenue West in Seattle, Washington (the "Building").

B.  Sublandlord
wishes to sublease to Subtenant 28,854 rentable square feet of the Building located on the second floor of the Building shown cross-hatched on
Exhibit B attached hereto (the "Subleased Premises").

NOW,
THEREFORE, in consideration of the mutual covenants contained in this Sublease, and for other good and valuable consideration, the receipt and sufficiency of which is hereby
acknowledged by the parties, Sublandlord and Subtenant hereby agree as follows:

AGREEMENT

1.Sublease

Sublandlord
hereby subleases to Subtenant and Subtenant hereby subleases from Sublandlord, for the Term, at the rental, and upon all of the conditions set forth herein, the Subleased
Premises, together with the right to use, in common with others entitled thereto, the hallways, stairways and elevators necessary for access to the Subleased Premises and the lavatories nearest to the
Subleased Premises.

2.Term and Possession



The
term of this Sublease ("Term") shall commence on November 1, 2000 ("Commencement Date"). The Term shall expire on October 31, 2003 ("Expiration Date"). Effective at
the end of the initial 24 months of the Sublease term, Sublandlord and Subtenant shall have the right to cancel the Sublease with nine months prior notice.



Sublandlord
shall deliver to Subtenant possession of the Subleased Premises on the Commencement Date in a turnkey condition ("Possession") pursuant to Sublandlord's construction
documents. If for any reason Sublandlord does not deliver Possession to Subtenant on the Commencement Date, Base Rent, as defined in Section 3.1, shall abate until delivery of Possession.
Attached is a plan that shows the "scope and nature" of improvements that will be provided.

3.Base Rent and Operating Expenses



Subtenant
shall pay to Sublandlord Base Rent on or before the first day of each calendar month during the Term. The monthly installments of Base Rent shall be prorated on a per diem
basis for the

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first or last month of the Term if the Commencement Date or Expiration Date is not the first day or last day of a calendar month.

Period

Monthly

AnnualNovember 1, 2000 to October 31, 2001

[*]

[*]November 1, 2001 to October 31, 2002

[*]

[*]November 1, 2002 to October 31, 2003

[*]

[*]




Subtenant
agrees to pay as Additional Rent its proportionate share of all expenses, as defined in Section 4 of the Master Lease, attributable to its lease of the Sublease
Premises, including all increases in said expenses over the term of the lease. Subtenant's percentage of the building area of Building Three is 26.20%.

4.Tenant Improvements

Sublandlord
shall provide scale floor plans for floor 2 including dimensions of private offices, conference rooms, kitchen or break rooms, cubicles, etc. Subtenant may make
modifications to the
attached plan, and will restore the Subleased Premises to its original condition at the end of the Sublease term at Subtenant's expense.

5.Parking

Subtenant
shall have the right to 1.9 stalls per 1,000 square feet of space leased throughout the term of the Sublease on an unreserved basis in the Building parking garage. The cost
for the stalls shall be at market rate.

6.Early Access

Subtenant
and Subtenant's contractors shall have early access to the Subleased Premises one month prior to occupancy by Subtenant, for Subtenant's installation of furniture,
equipment, telephone lines, data network wiring and security.

7.Security Deposit

Contemporaneously
with the execution hereof, Subtenant shall deposit with Sublandlord the sum of the first month's rent and the last three months' due (which equates to
[*]) as security for Subtenant's faithful performance of Sublandlord's obligations hereunder ("Security Deposit"). The Security Deposit shall be applied to Subtenant's last
month's rent due; provided, however, if Subtenant fails to pay rent or other charges when due under this Sublease, or fails to perform any of its obligations hereunder, Sublandlord may use or apply
all or any portion of the Security Deposit for the payment of any rent or other amount then due hereunder and unpaid, for the payment of any other sum for which Sublandlord may become obligated by
reason of Subtenant's default or breach, or for any loss or damage sustained by Sublandlord as a result of Subtenant's default or breach.

8.Use of Subleased Premises

The
Subleased Premises shall be used and occupied only for general office purposes and for any other purpose permitted under the Master Lease.

9.Assignment and Sublease

Subtenant
shall be permitted to sublease individual offices to any subagents and/or clients without obtaining Sublandlord's consent. Subtenant shall be permitted to sublease or assign
all or portion of the Subleased Premises subject to Sublandlord's and Landlord's consent per the terms and conditions of the Master Lease.

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10.Incorporation by Reference



This
Sublease is subject to all of the terms and condition of the Master Lease by and between Sublandlord and Landlord. Subtenant shall obtain insurance for the Subleased Premises and
name Sublandlord as an additional insured in the policy.



The
terms, conditions and respective obligations of Sublandlord and Subtenant to each other under this Sublease shall be the terms and conditions of the Master Lease except for those
provisions of the Master Lease which are directly contradicted by this Sublease, in which event the terms of this Sublease shall control over the Master Lease. Therefore, for the purposes of this
Sublease, wherever in the Master Lease the word "Lessor" is used it shall be deemed to mean the Sublandlord herein and wherever in the Master Lease the word "Lessee" is used it shall be deemed to mean
the Subtenant herein.

11.Sublandlord's Representations and Warranties

Sublandlord
represents and warrants to Subtenant as follows:



12.Covenants Regarding Lease



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13.Indemnification



Subtenant
shall indemnify, defend and hold harmless Sublandlord from and against all losses, costs, damages, expenses and liabilities, including, without limitation, reasonable
attorneys' fees and disbursements, which Sublandlord may incur or pay out (including, without limitation, to Landlord) by reason of (a) any accidents, damages or injuries to persons or property
occurring in, on or about the Subleased Premises (unless the same shall have been caused by Sublandlord's negligence or wrongful act or the negligence or wrongful act of Landlord), (b) any
breach or default hereunder on Subtenant's part, (c) the successful enforcement of Sublandlord's rights under this Section or any other Section of this Sublease, (d) any work done after
the date hereof in or to the Subleased Premises except if done by Sublandlord or Landlord, or (e) any act, omission or negligence on the part of Subtenant and/or its officers, partners,
employees, agents, customers and/or invitees, or any person claiming through or under Subtenant.



Sublandlord
shall indemnify, defend and hold harmless Subtenant from and against all losses, costs, damages, expenses and liabilities, including, without limitation, reasonable
attorneys' fees and disbursements, which Subtenant may incur or pay out (including, without limitation, to Landlord) by reason of (a) any accidents, damages or injuries to persons or property
occurring in, on or about any portion of the Master Premises other than the Subleased Premises (unless the same shall have been caused by Subtenant's negligence or wrongful act), (b) any breach
or default hereunder or under the Master Lease on Sublandlord's part, (c) the successful enforcement of Subtenant's rights under this Section or any other Section of this Sublease, or
(d) any act, omission or negligence on the part of Sublandlord and/or its officers, partners, employees, agents, customers and/or invitees, or any person claiming through or under Sublandlord.

14.Notices

All
notices and demands that may or are to be required or permitted are to be given by either party on the other hereunder shall be in writing. All notices and demands by Sublandlord
to Subtenant shall be personally delivered or sent by a nationally recognized private carrier of overnight mail (e.g. FedEx) or by United States Certified Mail, return receipt requested and postage
prepaid, to the parties

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at the addresses listed below or at such other addresses as the parties may designate by notice from time to time.

To Sublandlord:

F5 Networks, Inc
401 Elliott Ave West
Seattle, Washington 98119
Attention: Joann Reiter, General CounselTo Subtenant:

NeoRx Corporation
410 West Harrison Street
Seattle, Washington 98119
Attention: Paul Abrams, CEO


15.Quiet Enjoyment

Provided
that Subtenant is not in default of any term or provision of the Master Lease or this Sublease, Subtenant shall have peaceful and quiet enjoyment of the Subleased Premises
without interference from Sublandlord or any person or entity claiming by, through or under Sublandlord.

15.Attorney's Fees

If
Sublandlord or Subtenant shall commence an action against the other arising out of or in connection with this Sublease, the prevailing party shall be entitled to recover its costs
of suit and reasonable attorney's fees.

16.Entire Agreement

This
Sublease, the Exhibits attached hereto and the Master Lease, which is incorporated herein by reference, constitute the entire agreement between Sublandlord and Subtenant with
respect to the Subleased Premises and may not be amended or altered except by written agreement executed by both parties.

17.Binding on Successors

This
Sublease shall bind the parties' heirs, successors, representatives and permitted assigns.

IN
WITNESS WHEREOF, the parties hereto hereby execute this Sublease as of the day and year first above written.

|SUBLANDLORD:F5 Networks, Inc. |  | SUBTENANT:NeoRx Corporation Inc.
|----------------------------- |  | --------------------------------
|By                            |  | /s/ Robert J. Chamberlain       
|Name                          |  | Robert J. Chamberlain           
|Title                         |  | CFO                             
|                              |  |                                 

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|STATE OF WASHINGTON |  | )     |  | 
|------------------- |  | ----- |  | 
|                    |  | ) ss. |  | 
|COUNTY OF KING      |  | )     |  | 

On
this 24th day of July, 2000, before me, the undersigned, a Notary Public in and for the State of Washington, duly commissioned and sworn, personally appeared Robert J. Chamberlain,
to me known to be the person who signed as CFO of F5 NETWORKS, INC., the corporation that executed the within and foregoing instrument, and acknowledged said instrument to be the free and
voluntary act and deed of said corporation for the uses and purposes therein mentioned, and on oath stated that he was duly elected, qualified and acting as said officer of the corporation, that he
was authorized to execute said instrument and that the seal affixed, if any, is the corporate seal of said corporation.

IN
WITNESS WHEREOF I have hereunto set my hand and official seal the day and year first above written.

| |  | (Not Legible) G. GilbertSignature                                                                             
| |  | --------------------------------------------------------------------------------------------------------------
| |  | NOTARY PUBLIC in and for the State of Washington, residing at Snohomish County.
My appointment expires: 6/1/02

STATE
OF WASHINGTON

COUNTY
OF KING

On
this 14 day of July, 2000, before me, the undersigned, a Notary Public in and for the State of Washington, duly commissioned and sworn, personally appeared Paul G. Abrams,
to me known to be the person who signed as CEO of NEORX CORPORATION INC., the corporation that executed the within and foregoing instrument, and acknowledged said instrument to be the free and
voluntary act
and deed of said corporation for the uses and purposes therein mentioned, and on oath stated that he was duly elected, qualified and acting as said officer of the corporation, that he was authorized
to execute said instrument and that the seal affixed, if any, is the corporate seal of said corporation.

IN
WITNESS WHEREOF I have hereunto set my hand and official seal the day and year first above written.

| |  | /s/ T. H. CravenSignature
| |  | -------------------------

NOTARY PUBLIC in and for the State
of Washington, residing at Redmond, WA.
My appointment expires: 9/4/2003

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