**Exhibit 10.1****FOURTH AMENDMENT TO LEASE**     THIS FOURTH AMENDMENT TO LEASE (the “**Fourth Amendment**”), is made as of November 15, 2005 (the“**Effective Date**”), by and between ARE-METROPOLITAN GROVE I, LLC, a Delaware limited liabilitycompany (“**Landlord**”), and DIGENE CORPORATION, a Delaware corporation (“**Tenant**”).**RECITALS**     A. Pursuant to that certain Lease dated as of March 2, 1998, by and between Landlord andTenant, as amended by that certain First Amendment to Lease and Work Letter, dated June 30, 1998,as further amended by that certain Second Amendment to Lease and Work Letter, dated as of July 7,1999, and as further amended by that certain Third Amendment to Lease Agreement (the “**ThirdAmendment**”), dated October 31, 2001 (as amended, the “**Lease**”), Landlord leased to Tenant thatcertain premises (the “**Original Demised Premises**”) located within the building (the “**Building**”) at1201 Clopper Road, Gaithersburg, Maryland (with the Land, as defined in the Lease, the “**Property**”)and more particularly described in the Lease. The Property is part of the “**Project**” known asAlexandria Technology Center—Gaithersburg I, more particularly described in the Lease.Capitalized terms used but not defined herein shall have the meanings ascribed to them in theLease.     B. The Original Demised Premises initially comprised 92,990 rentable square feet, but has beenexpanded to increase its size by 17,435 rentable square feet (the “**First Expansion**”), for a totalof 110,425 rentable square feet, but Annual Base Rent under the Lease is calculated as if theOriginal Demised Premises comprised 120,100 rentable square feet. As used in this FourthAmendment, the Original Demised Premises shall be deemed to include the First Expansion.     C. Tenant desires to expand the Original Demised Premises by constructing two additions to theBuilding which will comprise, in the aggregate, approximately 33,160 additional rentable squarefeet. The first addition shall be located at the north end of the Building and will contain twostories of approximately 22,570 rentable square feet, in the aggregate, (the “**North Expansion**”),and the second addition shall be located at the east end of the Building and shall contain twostories of approximately 10,590 rentable square feet, in the aggregate (the “**East Expansion**”) (theNorth Expansion and the East Expansion collectively, the “**Expansion Space**”).     D. Landlord and Tenant desire to amend the Lease to, among other things, permit Tenant toconstruct the Expansion Space, and to add the Expansion Space to the Original Demised Premisesdemised under the Lease.**AGREEMENT**     Now, therefore, the parties hereto agree that the Lease is amended as follows:     1. **Demising of Expansion Space**. As of the Effective Date, Landlord hereby leases toTenant and Tenant hereby leases from Landlord the Expansion Space, and the Original
 

 
Demised Premises shall be deemed modified to include the Expansion Space. The Expansion Spaceis more fully described on **Exhibit A** attached hereto and incorporated herein. The OriginalDemised Premises, as expanded to include the Expansion Space, shall for purposes of the Lease bedeemed to mean the “**Demised Premises**”. The Expansion Space comprises 33,160 rentable square feet,and Annual Base Rent for the Expansion Space, the Shell Allowance, and the Additional TI Allowanceshall be calculated as if the Expansion Space comprised 33,160 rentable square feet, subject to aone time remeasurement of the Expansion Space as set forth below in this Section 1. As of theEffective Date, the Demised Premises shall be deemed to comprise 143,585 rentable square feet(calculated as 92,990 rentable square feet originally demised, plus 17,435 rentable square from theFirst Expansion, plus 33,160 rentable square feet of the Expansion Space). Upon SubstantialCompletion of the Expansion Space, Landlord shall cause the TI Architect (as defined in theExpansion Space Work Letter, attached hereto) to remeasure the Expansion Space in accordance withcurrent BOMA standards for single tenant properties (the “**Remeasurement**”). The cost of theRemeasurement shall be paid from the TI Fund, as defined in Section 6 of the Expansion Space WorkLetter attached hereto. The results of the remeasurement by the TI Architect shall be conclusivebetween the parties, and if necessary, the calculation of Annual Base Rent, Tenant’s Pro Rata Shareof Project Operating Expenses, the Shell Allowance, and the Additional TI Allowance shall berecalculated on the basis of the actual size of the Expansion Space, and the parties shall confirmsuch calculations in writing.     Notwithstanding anything herein to the contrary, Tenant’s continuing right to lease andconstruct the Expansion Space is subject to the condition that on or before May 1, 2006,Commencement of Construction (as defined below) of the Expansion Space shall have occurred, and ifas of such date, Commencement of Construction has not occurred, then Landlord shall have the right,in Landlord’s sole discretion, exercisable by delivering written notice to Tenant, to terminateTenant’s right to lease and construct the Expansion Space. Upon delivery of such notice, all ofthe terms of this Fourth Amendment shall be null and void, including without limitation Landlord’sobligation hereunder to provide the Expansion Space TI Allowance and the Additional Expansion SpaceTI Allowance, Landlord’s obligation to provide parking for the Expansion Space as set forth inSection 8 hereof, and Landlord’s obligation to make the Lot Line Adjustment (although in suchevent, nothing herein shall be deemed to prevent Landlord from making the Lot Line Adjustment, ifLandlord so determines in its sole discretion). In the event Landlord exercises its right toterminate Tenant’s right to lease and construct the Expansion Space as set forth in this Section 1of this Fourth Amendment, then as of the date of Landlord’s notice, the rentable area of theDemised Premises shall be reduced by 23,485 rentable square feet, and shall thereafter be deemed tobe 120,100 rentable square feet.     Thereafter, Tenant shall have no further right to lease or construct the Expansion Space. Forpurposes of this Section 1, “**Commencement of Construction**” shall mean that Tenant shall havecommenced in a material way the actual on-site work of construction of the Tenant Improvements (asdefined in the Expansion Space Work Letter), that the TI Contractor (as defined in the ExpansionSpace Work Letter) shall be on-site and proceeding without material interruption to complete thework of the Tenant Improvements, that Tenant shall have funded the Excess TI Costs, and that Tenantshall have made actual expenditure of at least 10% of the costs set forth in the Budget.
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     2. **Construction of Expansion Space**. Landlord and Tenant agree that the ExpansionSpace shall be constructed by Tenant in accordance with the terms and conditions set forth in theWork Letter attached hereto as **Exhibit B** and incorporated herein by reference (the“**Expansion Space Work Letter**”).     3. **Expansion Space Tenant Improvement Allowance**.          (a) Landlord shall provide to Tenant a tenant improvement allowance in an amount equal to$75.00 per rentable square foot of the Expansion Space, up to a maximum amount of $2,487,000.00(“**Shell Allowance**”), which may be used by Tenant pay the costs to construct the shell building ofthe Expansion Space, as more specifically set out in the Expansion Space Work Letter. The ShellAllowance is calculated at the rate of $75.00 per rentable square foot multiplied by 33,160rentable square feet, and is subject to change upon the Remeasurement as set forth in Section 1.          (b) In addition, Landlord shall provide Tenant, at Tenant’s election, an additional tenantimprovement allowance (the “**Additional TI Allowance**”) in an amount up to $100.00 per rentablesquare foot of the Expansion Space, up to a maximum amount of $3,316,000.00 in the aggregate, forTenant’s use in connection with the construction and installation of the remainder of the ExpansionSpace, as more specifically set out in the Expansion Space Work Letter. Any portion of theAdditional TI Allowance used by Tenant shall be repaid to Landlord as Expansion Improvement Rent(as defined below). The Additional TI Allowance is calculated at the rate of $100.00 per rentablesquare foot multiplied by 33,160 rentable square feet, and is subject to change upon theRemeasurement as set forth in Section 1.          (c) The Shell Allowance and Additional TI Allowance shall be administered, disbursed and usedin accordance with the terms and conditions of the Expansion Space Work Letter. In no event shallTenant use any portion of the Shell Allowance or the Additional TI Allowance to further improve,alter or otherwise renovate any part of the Original Demised Premises, other than as designated inthe TI Design Drawings and the TI Construction Drawings, prepared by the TI Architect as more fullyset forth in the Expansion Space Work Letter.     4. **Term**. The Term of the Lease (for both the Original Demised Premises and theExpansion Space) shall be extended continuously for a period of ten (10) years (the “**ExtensionTerm**”) commencing on Expansion Space Rent Commencement Date (defined below) and expiring on thetenth anniversary of the last day of the month in which the Expansion Space Rent Commencement Dateoccurs (the “**Extension Term Expiration Date**”). For purposes of the Lease, the “**Term**” of the Leaseis modified to mean the period from the Term Commencement Date through the Extension TermExpiration Date, subject to termination or extension as otherwise provided in the Lease.     5. **Annual Base Rent**.          (a) Commencing on the earlier to occur of (i) Substantial Completion (as defined in theExpansion Space Work Letter) of the Expansion Space or (ii) September 20, 2006, (the “**ExpansionSpace Rent Commencement Date**”), Tenant shall pay Annual Base Rent with respect to the ExpansionSpace, in Monthly Rental Installments of $42,831.67 per month,
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computed on the basis of $15.50 per annum per rentable square foot of the Expansion Spacemultiplied by 33,160 rentable square feet (subject to adjustment upon the Remeasurement).          (b) On each Adjustment Date during the Extension Term, Annual Base Rent on the Expansion Spaceshall be increased by 2.5%, provided that on the first Adjustment Date following the ExpansionSpace Rent Commencement Date, Annual Base Rent on the Expansion Space shall be increased by thatnumber resulting from multiplying 2.5% by a fraction, the numerator of which is the actual numberof days between the Expansion Rent Commencement Date and the first Adjustment Date and thedenominator of which is 365.          (c) Commencing on the Expansion Space Rent Commencement Date, Tenant’s Pro Rata Share ofProject Operating Expenses shall be increased to 40.53% (based on 143,585 rentable square feet inthe Demised Premises, and 354,258 rentable square feet in the Project).          (d) Annual Base Rent on the Original Demised Premises shall continue to be payable accordingto the rent schedule attached as Exhibit A to the Third Amendment through December 31, 2009. OnJanuary 1, 2010, and on each Adjustment Date thereafter during the Extension Term, Annual Base Renton the Original Demised Premises shall be increased by 2.5%.          (e) “**Adjustment Date**” shall mean January 1 of any year during the Extension Term.     6. **Improvement Rent**. In the event Tenant elects to receive the Additional TIAllowance, Tenant agrees to pay to Landlord, as Additional Rent, Expansion Space Improvement Rentas set forth in this Section 6. As of the Expansion Space Rent Commencement Date, the amount ofthe Additional TI Allowance actually disbursed shall be amortized over the Extension Term with ninepercent (9%) annual interest. “**Expansion Space Improvement Rent**” shall mean the monthly amortizedamount of such amortization, which shall be due and payable monthly by Tenant in the same manner asset forth in the Lease for the payment of Annual Base Rent. Expansion Space Improvement Rent shallnot be subject to annual adjustment on any Adjustment Date. For purposes of the Lease, the term“**Improvement Rent**” shall hereinafter include the Expansion Space Improvement Rent. In the event ofa termination of the Lease prior to the Extension Term Expiration Date, the full unamortized amountof the Additional TI Allowance shall be automatically due and payable as Additional Rent by Tenant.In addition, the Shell Allowance shall be amortized in the same manner as the Additional TIAllowance, but the monthly amount of such amortization shall not be payable by Tenant. If theLease is terminated prior to the Extension Term Expiration Date, then the full unamortized amountof the Shell Allowance shall be automatically due and payable as Additional Rent.     7. **Density**. The parties acknowledge that the Expansion Space will increase the floorarea ratio density for the Property beyond that which is permitted by applicable law. The partiesfurther acknowledge that Landlord’s affiliate, ARE-30 West Watkins, LLC, a Delaware limitedliability company (“**Landlord’s Affiliate**”) is the owner of real property which is part of theProject and adjacent to the Property, at an address commonly known as 30 West Watkins
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Mill Road (the “**Adjacent Property**”). Landlord, Landlord’s Affiliate and Tenant shallcooperate to adjust the location of the property line between the Adjacent Property and theProperty (the “**Lot Line Adjustment**”) in order to increase the floor area ratio density of theProperty to permit the construction of the Expansion Space. All costs of the Lot Line Adjustmentshall be paid by Tenant, when due and payable from time to time, as Additional Rent under the Leaseto include, but not limited to, Landlord’s and Landlord’s Affiliate’s legal fees and lender reviewfees, map recordation fees, easement preparation and recordation fees, and all governmentprocessing fees. The parties acknowledge that Landlord intends to grant Landlord’s Affiliate, asthe owner of the Adjacent Property, an easement to use that portion of the Adjacent Property whichis transferred to Landlord by the Lot Line Adjustment, so that Tenant shall have no right to theuse of any portion of the Adjacent Property which is the subject of the Lot Line Adjustment.Landlord’s Affiliate has joined this Fourth Amendment for the limited purpose of confirming itsagreement to the terms of this Section 7.     8. **Additional Parking**. Landlord agrees to provide Tenant, at Landlord’s sole cost andexpense, parking for the Expansion Space, in a location shown on the parking map attached to thisFourth Amendment as **Exhibit D**.     9. **Governmental Permits and Approvals**. Tenant shall be responsible, at its sole costand expense, for applying for and obtaining all state and/or local government permits and approvalsrequired in connection with the construction and occupancy of the Expansion Space, includingwithout limitation all permits or approvals necessary to permit the construction of the ExpansionSpace, including the Lot Line Adjustment. Landlord shall, at no cost or expense to Landlord,cooperate with Tenant as may be reasonably required in connection with Tenant’s obtaining suchpermits and approvals.     10. **Termination Option**.          (a) Section 3.3 of the Lease is hereby deleted and replaced in its entirety as follows:“Notwithstanding anything to the contrary contained herein, Tenant shall have theright, in its sole and absolute discretion, to terminate this Lease, whichtermination shall be effective at the end of the fifth year after the ExpansionSpace Rent Commencement Date, upon not less than twelve (12) months prior writtennotice to Landlord, which notice, as a condition to its effectiveness and theeffectiveness of any termination, shall be accompanied by the payment of theTermination Amount. Upon the effective date of such termination made pursuant tothis paragraph, this Lease shall terminate and all of the rights and obligations ofthe parties hereunder shall thereafter cease and terminate, except pursuant to anyprovision which expressly survives the termination hereof, including withoutlimitation, Tenant’s indemnification obligations set forth in Article 38 of thisLease and Tenant’s obligations and liabilities which accrue or arise prior to thetermination date of this Lease, including, without limitation, Tenant’s obligationto pay any and all Rent which accrued prior to such termination date.”
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          (b) Section 41.28 of the Lease is hereby deleted and is replaced in its entirety as follows:     “**Termination Amount**” shall mean an amount equal to the present value of the sum ofAnnual Base Rent, Improvement Rent and Additional Rent anticipated to become due during theperiod from the fifth anniversary of the Expansion Space Rent Commencement Date through theExtension Term Expiration Date (had the Lease not been terminated) discounted at a discountrate of 8%.”     11. **Expansion Space Rent Commencement Date and Extension Term Expiration Date**. Tenantshall execute and deliver a written acknowledgment of the Expansion Space Rent Commencement Dateand the Extension Term Expiration Date in the form attached hereto as **Exhibit C**; providedhowever, Tenant’s failure to execute and deliver such acknowledgment shall not affect Landlord’srights hereunder.     12. **Miscellaneous**.          (a) This Fourth Amendment is the entire agreement between the parties with respect to thesubject matter hereof and supersedes all prior and contemporaneous oral and written agreements anddiscussions. This Fourth Amendment may be amended only by an agreement in writing, signed by theparties hereto.          (b) This Fourth Amendment is binding upon and shall inure to the benefit of the partieshereto, their respective agents, employees, representatives, officers, directors, divisions,subsidiaries, affiliates, assigns, heirs, successors in interest and shareholders.          (c) This Fourth Amendment may be executed in any number of counterparts, each of which shallbe deemed an original, but all of which when taken together shall constitute one and the sameinstrument. The signature page of any counterpart may be detached therefrom without impairing thelegal effect of the signature(s) thereon provided such signature page is attached to any othercounterpart identical thereto except having additional signature pages executed by other parties tothis Fourth Amendment attached thereto.          (d) Landlord and Tenant each represent and warrant that it has not dealt with any broker,agent or other person in connection with this transaction, and that no broker brought about thistransaction. Landlord and Tenant each hereby agree to indemnify and hold the other harmless fromand against any claims by any broker claiming a commission or other form of compensation by virtueof having dealt with Tenant or Landlord, as applicable, with regard to this transaction.          (e) Except as amended and/or modified by this Fourth Amendment, the Lease is hereby ratifiedand confirmed and all other terms of the Lease shall remain in full force and effect, unaltered andunchanged by this Fourth Amendment. In the event of any conflict between the provisions of thisFourth Amendment and the provisions of the Lease, the provisions of this Fourth Amendment shallprevail. Whether or not specifically amended by this Fourth Amendment, all of the terms andprovisions of the Lease are hereby amended to the extent necessary to give effect to the purposeand intent of this Fourth Amendment.
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     IN WITNESS WHEREOF, the parties hereto have executed this Fourth Amendment as of the day andyear first above written.                        **TENANT:**                   DIGENE CORPORATION,    a Delaware corporation               By: /s/ Charles M. Fleischman               Name: Charles M. Fleischman    Title: President and Chief Operating Officer             **LANDLORD:**                   ARE-METROPOLITAN GROVE I, LLC,  a Delaware limited liability company             By: ALEXANDRIA REAL ESTATE EQUITIES, L.P.,    a Delaware limited partnership,      managing member                 By: ARE-QRS CORP.,        a Maryland corporation        its general partner                   By: /s/ Jennifer Pappas                     Name: Jennifer Pappas                     Title: V.P. & Assistant Secretary             
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**JOINDER BY LANDLORD’S AFFILIATE**:The undersigned hereby joins this Fourth Amendment for the limited purpose of confirming theprovisions of Section 7 of this Fourth Amendment:           ARE-30 WEST WATKINS, LLC,  a Delaware limited liability company           By: ALEXANDRIA REAL ESTATE EQUITIES, L.P.,      a Delaware limited partnership,      managing member              By: ARE-QRS CORP.,        a Maryland corporation,        general partner                 By: /s/ Jennifer Pappas                 Name: Jennifer Pappas                 Title: V.P. & Assistant Secretary           
 

 
**EXHIBIT A****DEMISED PREMISES**EXHIBIT A
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**EXHIBIT B****EXPANSION SPACE WORK LETTER**     THIS EXPANSION SPACE WORK LETTER dated as of November 15, 2005 (this “**Work Letter**”) is madeand entered into by and between ARE-METROPOLITAN GROVE I, LLC, a Delaware limited liability company(“**Landlord**”), and DIGENE CORPORATION, a Delaware corporation (“**Tenant**”), and is attached to andmade a part of the Fourth Amendment to Lease dated as of even date herewith (the “**FourthAmendment**”), by and between Landlord and Tenant. Any initially capitalized terms used but notdefined herein shall have the meanings given them in the Fourth Amendment.     1. **General Requirements**          (a) **Tenant’s Authorized Representative**. Tenant designates Charles Fleishman and Larry Wellman(either such individual acting alone, “**Tenant’s Representative**”) as the only persons authorized toact for Tenant pursuant to this Work Letter. Landlord shall not be obligated to respond to or actupon any request, approval, inquiry or other communication (“**Communication**”) from or on behalf ofTenant in connection with this Work Letter unless such Communication is in writing from Tenant’sRepresentative. Tenant may change either Tenant’s Representative at any time upon not less than 5business days advance written notice to Landlord. No period set forth herein for any approval ofany matter by Tenant’s Representative shall be extended by reason of any change in Tenant’sRepresentative. Whenever this Work Letter requires that Tenant’s Representative notify eitherLandlord or Landlord’s Representative in writing, such notice may be made by a facsimiletransmission and/or electronic (e-mail) notification.          (b) **Landlord’s Authorized Representative**. Landlord designates Larry Diamond and Vin Ciruzzi(either such individual acting alone, “**Landlord’s Representative**”) as the only persons authorizedto act for Landlord pursuant to this Work Letter. Tenant shall not be obligated to respond to oract upon any request, approval, inquiry or other Communication from or on behalf of Landlord inconnection with this Work Letter unless such Communication is in writing from Landlord’sRepresentative. Landlord may change Landlord’s Representative at any time upon not less than 5business days advance written notice to Tenant. No period set forth herein for any approval of anymatter by Landlord’s Representative shall be extended reason of any change in Landlord’sRepresentative. Whenever this Work Letter requires that Landlord’s Representative notify eitherTenant or Tenant’s Representative in writing, such notice may be made by a facsimile transmissionand/or electronic (e-mail) notification.          (c) **Architects, Consultants and Contractors**. Landlord and Tenant hereby acknowledge andagree that DNC Architects has been mutually approved as the architect (the “**TI Architect**”) for theTenant Improvements (as defined below), and the Whiting-Turner Contracting Company has beenmutually approved as the general contractor (the “**TI Contractor**”). Any subcontractors for theTenant Improvements shall be selected by Tenant, subject to Landlord’s approval, which approvalshall not be unreasonably withheld, conditioned or delayed.EXHIBIT B
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          (d) **Development Schedule**. The Tenant Improvements may be completed in one or more phases, andthe schedule for design and development of each phase of the Tenant Improvements, including withoutlimitation the time periods for delivery of construction documents and performance, shall be insubstantially the form attached hereto as Schedule A (each development schedule is hereina “**Development Schedule**”). For each phase of the Tenant Improvements, Tenant shall prepare anddeliver to Landlord a Development Schedule, which shall be subject to Landlord’s reasonableapproval. Tenant shall use commercially reasonable efforts to complete that portion of the TenantImprovements in accordance with any approved Development Schedule.     2. **Tenant Improvements**          (a) **Tenant Improvements Defined**. As used herein, “**Tenant Improvements**” shall mean allimprovements to the Expansion Space, desired by Tenant of a fixed and permanent nature. Other thanfunding the TI Allowances (as defined below) as provided herein, Landlord shall not have anyobligation whatsoever with respect to the finishing of the Expansion Space.          (b) **Tenant’s Space Plans**. Tenant has previously delivered to Landlord schematic drawings andoutline specifications (the “**TI Design Drawings**”) detailing Tenant’s requirements for the TenantImprovements. Landlord shall promptly upon execution and delivery of the Lease deliver to Tenantthe written objections, questions or comments of Landlord and the TI Architect with regard to theTI Design Drawings. Tenant shall cause such TI Design Drawings to be revised to address Landlord’swritten comments and shall resubmit said drawings to Landlord for approval within 10 business daysthereafter. Such process shall be repeated until Landlord has approved the TI Design Drawings.          (c) **Working Drawings**. On or before the date shown in the Development Schedule, Tenant shallcause the TI Architect to prepare and deliver to Landlord for review and comment constructionplans, specifications and drawings for the Tenant Improvements (“**TI Construction Drawings**”), whichTI Construction Drawings shall be prepared substantially in accordance with the TI Design Drawings.Tenant shall be solely responsible for ensuring that the TI Construction Drawings reflect Tenant’srequirements for the Tenant Improvements. Landlord shall deliver its written comments on the TIConstruction Drawings to Tenant not later than 10 business days after Landlord’s receipt of thesame; provided, however, that Landlord may not disapprove any matter that is consistent with the TIDesign Drawings. Tenant and the TI Architect shall consider all such comments in good faith andshall, within 10 business days after receipt, notify Landlord how Tenant proposes to respond tosuch comments. Any disputes in connection with such comments shall be resolved in accordance withSection 2(d) hereof. Provided that the design reflected in the TI Construction Drawings isconsistent with the TI Design Drawings, Landlord shall approve the TI Construction Drawingssubmitted by Tenant. Once approved by Landlord, subject to the provisions of Section 2(d) below,Tenant shall not materially modify the TI Construction Drawings except as may be reasonablyrequired in connection with the issuance of the TI Permit (as defined in Section 4(b) below).EXHIBIT B
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          (d) **Approval and Completion**. Upon any dispute regarding the design of the TenantImprovements, which is not settled within 10 business days after notice of such dispute isdelivered by one party to the other, Tenant shall make the final decision regarding the design ofthe Tenant Improvements, provided that (i) Landlord shall make the final decision regarding thedesign of the shell of the Building, (ii) Tenant and Landlord act reasonably and such finaldecisions are either consistent with or a compromise between Landlord’s and Tenant’s positionswith respect to such dispute, and (iii) all costs and expenses resulting from any such decision byTenant shall be payable out of the TI Fund, as defined in Section 5(d) below. Any changes to theTI Construction Drawings following Landlord’s and Tenant’s approval of same requested by Tenantshall be processed as provided in Section 4 hereof (regarding Changes).     3. **Performance of Tenant Improvements.**          (a) **Commencement and Permitting of Tenant Improvements**. Tenant shall commence construction ofeach phase of the Tenant Improvements upon obtaining and delivering a building permit (the “**TIPermit**”) authorizing the construction of the applicable phase of the Tenant Improvements consistentwith the TI Construction Drawings approved by Landlord. The cost of obtaining the TI Permit shallbe payable from the TI Fund. Consistent with its obligations under this Work Letter and to theextent not detrimental to Landlord’s interests, Landlord shall assist Tenant in obtaining the TIPermit.          (b) **Selection of Materials, Etc.**Where more than one type of material or structure isindicated on the TI Construction Drawings approved by Tenant and Landlord, the option will bewithin Tenant’s reasonable discretion regarding the Tenant Improvements, provided that Landlordshall make any such decision regarding the shell of the Building.          (c) **Completion of Tenant Improvements**. The Tenant Improvements shall be deemed substantiallycomplete when the Tenant Improvements are completed in a good and workmanlike manner in accordancewith the TI Permit, subject only to Minor Variations and normal “punch list” items of anon-material nature which do not interfere with the use of the Premises (“**Substantial Completion**”).For purposes of this Work Letter, “**Minor Variations**” shall mean any modifications reasonablyrequired: (i) to comply with all applicable Legal Requirements and/or to obtain or to comply withany required permit; (ii) to comport with good design, engineering, and construction practiceswhich are not material; or (iii) to make reasonable adjustments for field deviations or conditionsencountered during the construction of the Tenant Improvements.     4. **Changes**. Any changes requested by Tenant to the Tenant Improvements after the delivery andapproval by Landlord of the TI Design Drawings, shall be requested and instituted in accordancewith the provisions of this Section 4.          (a) **Tenant’s Right to Request Changes**. If Tenant shall request changes (“**Changes**”), Tenantshall request such Changes by notifying Landlord in writing in substantially the same form as theAIA standard change order form (a “**Change Request**”), which Change Request shall detail the natureand extent of any such Change. Such Change Request must be signed by Tenant’s Representative.Landlord shall review and approve or disapprove such Change Request within 10 business daysthereafter, provided that (i) Landlord’s approval shallEXHIBIT B
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not be unreasonably withheld, conditioned or delayed for any Change Request which does notrelate to the shell of the Building, and (ii) Landlord’s approval may be given or withheld inLandlord’s sole discretion for any Change Request which relates to the shell of the Building.          (b) **Implementation of Changes**. If Landlord approves such Change Request and Tenant depositswith Landlord any Excess TI Costs (as defined in Section 5(d) below) required in connection withsuch Change, Tenant may cause the approved Change to be instituted.     5. **Costs**          (a) **Budget For The Tenant Improvements**. Before the commencement of construction of the TenantImprovements, Tenant shall obtain and deliver to Landlord a detailed breakdown, by trade, of thecosts incurred or which will be incurred, in connection with the design and construction of theTenant Improvements (the “**Budget**”). The Budget shall be based upon the TI Construction Drawingsapproved by Landlord and shall include a payment to Landlord of administrative rent(“**Administrative Rent**”) equal to 3.0% of the hard construction related costs of the TenantImprovements for monitoring and inspecting the construction of Tenant Improvements, which sum shallbe payable from the TI Fund. If the Budget is greater than the TI Allowances, Tenant shall depositwith Landlord the difference, in cash, prior to the commencement of construction of the applicableportion of the Tenant Improvements, for disbursement by Landlord as described in Section 5(d).          (b) **TI Allowances**. Landlord shall provide to Tenant certain improvement allowances(collectively, the “**TI Allowances**”) as follows (and as set forth in Section 3 of the FourthAmendment):               (i) a tenant improvement allowance in the maximum amount of $75.00 per rentable square foot inthe Expansion Space, or $2,487,000 in the aggregate, which is to be applied to the costs ofconstructing the shell of the Expansion Space, and is included in the Annual Base Rent for theExpansion Space set forth in the Fourth Amendment (the “**Shell Allowance**”); and               (ii) an additional tenant improvement allowance in the maximum amount of $100.00 per rentablesquare foot in the Expansion Space, or $3,316,000 in the aggregate (the “**Additional TI Allowance**”),which shall, to the extent used, shall be repaid as Expansion Space Improvement Rent in accordancewith the terms of Section 6 of the Fourth Amendment.     Prior to the commencement of construction of the Tenant Improvements, Tenant shall notifyLandlord of how much of the TI Allowances Tenant has elected to receive from Landlord, and how muchof the TI Allowances Tenant has elected to use towards any portion of the Tenant Improvements.Such election shall be final and binding on Tenant, and may not thereafter be modified withoutLandlord’s consent, which may be granted or withheld in Landlord’s sole and absolute discretion.The TI Allowances shall be disbursed in accordance with this Work Letter. Tenant may not use anyportion of any of the TI Allowances after the first anniversary of the Expansion Term CommencementDate. Tenant may not use more than $1,692,750 of the ShellEXHIBIT B
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Allowance for the construction of the shell for the North Expansion, and not more than $794,250 ofthe Shell Allowance for the construction of the shell for the East Expansion. Tenant may not usemore than $2,257,000 of the Additional TI Allowance for the construction of the Tenant Improvementsfor the North Expansion, and not more than $1,059,000 of the Additional TI Allowance for theconstruction of the Tenant Improvements for the East Expansion.          (c) **Costs Includable in TI Fund**. The TI Fund shall be used solely for the payment of designand construction costs of the Tenant Improvements, including, without limitation, the cost ofpreparing the TI Design Drawings and the TI Construction Drawings, all costs set forth in theBudget, including Landlord’s Administrative Rent, and the cost of Changes (collectively, “**TICosts**”). Notwithstanding anything to the contrary contained herein, the TI Fund shall not be usedto purchase any furniture, personal property, Tenant’s voice or data cabling, or other non-BuildingSystem materials or equipment not incorporated into the Improvements.          (d) **Excess TI Costs**. Landlord is under no obligation to bear any portion of the cost of theTenant Improvements except to the extent of the TI Allowances. Before the commencement ofconstruction of the Tenant Improvements, if at any time the remaining TI Costs under the Budgetexceed the unexpended TI Allowances which Tenant has elected to receive, Tenant shall deposit withLandlord, as a condition precedent to Landlord’s obligation to fund the TI Allowances, 100% of thethen current TI Cost in excess of the remaining TI Allowances (“**Excess TI Costs**”). If Tenant failsto deposit, or is late in depositing the Excess TI Costs with Landlord, Landlord shall have all ofthe rights and remedies set forth in the Lease for nonpayment of Rent (including, but not limitedto, the right to interest at the Default Rate and the right to assess a late charge), and forpurposes of any litigation instituted with regard to such amounts the same will be considered Rent.Such deposit of Excess TI Costs, together with the TI Allowances, is herein referred to as the “**TIFund**”. Funds so deposited by Tenant shall be the first disbursed to pay TI Costs before thedisbursement of any portion of the TI Allowances. Tenant shall be fully and solely liable for TICosts and the cost of Minor Variations in excess of the TI Allowances. If upon SubstantialCompletion of the Tenant Improvements and the payment of all sums due in connection therewith thereremains any undisbursed portion of the TI Fund, Tenant shall be entitled to such undisbursed TIFund solely to the extent of any Excess TI Costs deposit Tenant has actually made with Landlord.          (e) **Payment for TI Costs**. Commencing December 1, 2005, and subject to the condition precedentthat Tenant shall have met all of its obligations hereunder (including without limitation itsobligation to deliver to Landlord the Budget and deposit the full amount of Excess TI Costs),Landlord shall pay TI Costs once a month against a draw request in Landlord’s standard form,containing such certifications, lien waivers, inspection reports and other matters as Landlordcustomarily obtains, to the extent of Landlord’s approval thereof for payment, no later than 30days following receipt of such draw request. Notwithstanding the foregoing provision, Landlord maydisburse portions of the Excess TI Costs deposited by Tenant prior to December 1, 2005 to pay TICosts. Upon completion of each phase of the Tenant Improvements, Tenant shall deliver to Landlord:(i) sworn statements setting forth the names of all contractors and subcontractors who did the workand final lien waivers from all such contractors and subcontractors; and (ii) “as built” plans inboth print and electronic (CAD) format for such portion of the Tenant Improvements. Landlord willpay TI Costs directly to the TI Contractor.EXHIBIT B
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6. **Miscellaneous**          (a) **Consents**. Whenever consent or approval of either party is required under this WorkLetter, that party shall not unreasonably withhold, condition or delay such consent or approval,except as may be expressly set forth herein to the contrary.          (b) **Modification**. No modification, waiver or amendment of this Work Letter or of any of itsconditions or provisions shall be binding upon Landlord or Tenant unless in writing signed byLandlord and Tenant.          (c) **Counterparts**. This Work Letter may be executed in any number of counterparts but allcounterparts taken together shall constitute a single document.          (d) **Governing Law**. This Work Letter shall be governed by, construed and enforced inaccordance with the internal laws of the state in which the Demised Premises are located, withoutregard to choice of law principles of such State.          (e) **Time of the Essence**. Time is of the essence of this Work Letter and of each and allprovisions thereof.          (f) **Default**. Notwithstanding anything set forth herein or in the Lease to the contrary,Landlord shall not have any obligation to perform any work hereunder or to fund any portion of theTI Fund during any period Tenant is in Default under the Lease.          (g) **Severability**. If any term or provision of this Work Letter is declared invalid orunenforceable, the remainder of this Work Letter shall not be affected by such determination andshall continue to be valid and enforceable. To the extent any term or provision of this WorkLetter is declared invalid or unenforceable, Tenant and Landlord shall, using good faith efforts,revise this Work Letter to address the invalid or unenforceable term or provision in a manner (tothe extent possible) which will nevertheless provide Tenant and/or Landlord with the benefits orimpose the obligations intended to be provided or imposed by the invalid or unenforceable term orprovision.          (h) **Merger**. All understandings and agreements, oral or written, heretofore made between theparties hereto and relating to Tenant Improvements are merged in this Work Letter, which alone (butinclusive of provisions of the Lease incorporated herein and the final approved constructionsdrawings and specifications prepared pursuant hereto) fully and completely expresses the agreementbetween Landlord and Tenant with regard to the matters set forth in this Work Letter.          (i) **Entire Agreement**. This Work Letter is made as a part of the Fourth Amendment, andtogether with the Lease, constitutes the entire agreement of the parties with respect to thesubject matter hereof. This Work Letter is subject to all of the terms and limitation set forth inthe Lease, and neither party shall have any rights or remedies under this Work Letter separate andapart from their respective remedies pursuant to the Lease.EXHIBIT B
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     IN WITNESS WHEREOF, Landlord and Tenant have executed this Work Letter to be effective on thedate first above written.           **TENANT:**               **DIGENE CORPORATION**,    a Delaware corporation             By: /s/ Charles M. Fleischman           Name: Charles M. Fleischman    Title: President and Chief Operating Officer           **LANDLORD:**             **ARE-METROPOLITAN GROVE I, LLC**,    a Delaware limited liability company             By: **ALEXANDRIA REAL ESTATE EQUITIES,**    **L.P.**, a Delaware limited partnership,    managing member             By: ARE-QRS CORP.,      a Maryland corporation      its general partner             By: /s/ Jennifer Pappas             Name: Jennifer Pappas               Title: V.P. & Assistant Secretary       EXHIBIT B
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**SCHEDULE A TO WORK LETTER****Development Schedule**   Event  DateDeliveryof space plans for TI Design Drawings pursuant to Section 2(b) of the Work Letter done   Delivery of TI Construction Drawings pursuant to December 2, 2005Section 2(c) of the Work Letter    Delivery of Building Permit By January 1, 2006   Commence construction of phase Tenant Improvements By May 1, 2006   Substantial Completion of phase Tenant Improvements By September 20, 2006   Recordation of Lot Line Adjustment September 20, 2006   Issuance of Temporary Certificate of Occupancy for September 20, 2006phase of Tenant Improvements  SCHEDULE A TO