Document:

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                                                                 Exhibit 10.27

                               TENANCY AGREEMENT

                DRAWN UP AND SIGNED IN JERUSALEM ON DEC. 21, 2000

BETWEEN:     RMPA PROPERTIES LTD.
             Company number 51-1808008 (represented by __________, ID no.
             ________, ID no. _________, authorized to sign on its behalf)
             whose address is RMPA House, Har Hotzvim, Jerusalem (hereinafter
             "THE LESSOR") PARTY OF THE FIRST PART
AND:         KERYX ISRAEL LTD.
             Company number 51-2850959
             (represented by Mr. Ira Weinstein, ID no. 015476542, authorized to
             sign on its behalf)
             Qiryat Mada St. 5, Jerusalem
             (hereinafter "THE LESSEE")                PARTY OF THE SECOND PART
Whereas      The lessor is entitled to be registered as leaseholder from the
             Israel Lands Administration of lot number 18 according to detailed
             plan number 3760 (hereinafter "THE LOT") in parcel 95, block 30241,
             in Har Hotzvim, Jerusalem, on which a Building is being erected
             that is currently in the final stages of construction (hereinafter
             "THE Building"); and
Whereas      The lessee wishes to lease from the lessor the second and third
             floors (above the ground floor) in the Building, as marked on the
             plans attached to this agreement as Appendix A (hereinafter "THE
             LEASED PREMISES"), whose gross area (including the proportional
             share of common {public may imply use by outsiders, too} areas in
             the Building) is 2142 square meters (the third floor is a partial
             floor only), and the lessor wishes to lease to the lessee the
             Leased Premises as unprotected tenancy (hereinafter "THE TENANCY"),
             for a period of time, consideration, and purpose, and subject to
             the stipulations and provisions detailed in this contract below;

NOW THEREFORE, AND IN CONSIDERATION OF THE MUTUAL UNDERTAKINGS BY THE PARTIES
UNDER THE PRESENT CONTRACT, THE PARTIES AGREE AND STIPULATE AS FOLLOWS:

1.      PREAMBLE, APPENDICES, AND HEADINGS

        1.1    The preamble to this contract is an integral part thereof.

        1.2    The appendices to this contract are an integral part thereof.

        1.3    The section headings in this contract are included for ease of
               reading only. They are not part of the contract and shall not be
               used to interpret it.

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2.      THE TENANCY

        2.1    The lessee declares that it is aware that the according to the
               City Building Plan the area is earmarked for industry and that it
               has seen and inspected the Building and the Leased Premises, the
               access routes to them, and their surroundings, the City Building
               Plans that apply to them, and everything else it may have found
               it appropriate to inspect and found all of them to be suitable to
               its objectives, and, subject to the correctness of the lessor's
               statements as above, hereby waives any claim concerning
               unsuitability and any other alternative claim with regard to the
               Building and/ or with regard to the Leased Premises and/ or with
               regard to the possibility of using the Leased Premises for its
               purposes. The lessor affirms that it is not aware of any defect
               whatsoever in the Leased Premises and/ or in the possibility of
               using the Leased Premises for high- tech industry that it has not
               disclosed to the lessee.

        2.2    The lessee declares that based on its inspection it is leasing
               the premises as is. The lessor undertakes to carry out work on
               the Building as enumerated in the specifications attached to the
               present agreement, at the time stated in the present agreement.
               Subject to the performance of the aforesaid work, the lessee
               hereby waives any claim of any type whatsoever with regard to the
               Leased Premises, their condition, and the possibility of using
               them.

        2.3    The lessor undertakes that by the date of the completion of the
               Leased Premises as stated in section 5 below and its actual
               tenanting for the purpose of the Tenancy, as defined below,
               construction of the common areas on the floors on which the
               Leased Premises are located and of the Building lobby will be
               completed, (at least) one elevator will be operating in a regular
               and proper fashion, development work will have been carried out
               at the entrance to the Building in a manner that permits
               pedestrian access from street level to the Building entrance, and
               the lessor will be in possession of Form 4 for the Building and/
               or a tenanting certificate applying to the Leased Premises,
               including a temporary certificate.

3.      NON-APPLICATION OF TENANT PROTECTION LAWS

        3.1    The lessee hereby declares, undertakes, and affirms that it is
               aware that the Leased Premises are a property in a new Building
               whose construction was completed after August 20, 1968; that on
               August 20, 1968, it was not a tenant entitled to occupy the
               Leased Premises; and that sections 9 and 14 of the Tenant
               Protection Law (Consolidated Version) 5732-1972, which exempt the
               Tenancy from the provisions of the tenant protection laws, apply
               to the Tenancy under the present agreement.

        3.2    The lessee hereby declares that it was not asked to and did not
               pay key money or payments that might be construed as key money;
               and that all work, modifications, renovations, and improvements
               that may be carried out on the Leased Premises, should such be
               carried out, are not and will not be fundamental modifications;
               and that at the time of vacation of the

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               Leased Premises the lessee will not be entitled to any payment
               whatsoever, neither as key money nor in any other fashion
               whatsoever.

        3.3    The Tenancy, the lessee, and the Leased Premises are not
               protected under the provisions of the Tenant Protection Law
               (consolidated version) 5732-1972 nor by the provisions of any
               other law that protects a lessee or tenant in any form
               whatsoever, and the stated laws and amendments to them and
               regulations that have been or may be promulgated pursuant to them
               do not apply and shall not apply to the Tenancy, the lessee, the
               Leased Premises, or the contract.

4.      PURPOSE OF THE TENANCY

        The lessee hereby leases the Leased Premises in order to use them for
        high- tech industry (including a biopharmaceutical laboratory) and for
        no other purpose whatsoever (hereinafter "PURPOSE OF THE TENANCY") and
        hereby undertakes not to use the Leased Premises or any part thereof for
        any other purpose whatsoever.

5.      FINISHING WORK ON THE LEASED PREMISES

        5.1    The lessee, itself or by the agency of someone acting on its
               behalf, will carry out modifications and Finishing Work
               (hereinafter "THE FINISHING WORK") on the Leased Premises. Before
               the Finishing Work is carried out, the lessee will submit for the
               lessor's approval detailed plans for the Finishing Work,
               including, and without derogating from the generality of the
               aforesaid, air- conditioning and electrical plans and any other
               and/ or additional plan that alters the systems of the Leased
               Premises or its appearance or its structural engineering, as well
               as specifications. The lessor will examine the aforesaid plans
               and approve them or make comments within five days of receiving
               the stated plans. The lessee will amend the plans in accordance
               with the lessor's comments. Without derogating from the
               aforesaid, the lessee shall not be entitled to carry out
               Finishing Work on the Leased Premises that modifies the
               structural engineering of the Building and/ or its systems and/
               or its appearance and/ or Finishing Work that requires a Building
               permit for its performance.

               The lessee undertakes that the contractor who carries out the
               Finishing Work will be a contractor whose identity has been
               approved and agreed to in advance by the lessor, which shall be
               entitled to withhold or grant its consent, at its own reasonable
               discretion.

               In all cases the contractors proposed as stated shall be
               contractors registered in the appropriate classification for the
               type of Finishing Work to be done and who have carried out
               similar work at Har Hotzvim or the Malha Technological Park or
               some other high- tech park in Tel Aviv, such as Kiryat Atidim,
               and who have experience in work of the type of the Finishing
               Work.

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               The lessee shall notify the lessor of the starting date of the
               Finishing Work and the planned completion date. The lessor
               [translated as written] undertakes to complete the work according
               to the specifications within 90 days of the starting date of the
               Finishing Work, in accordance with the lessee's notification.

               Should the lessor fail to complete the work in accordance with
               the specifications by the aforesaid date or within 14 additional
               days, the lessor shall pay the lessee on account of the period
               from the date on which it was to have completed the work in
               accordance with the specifications until the date of their actual
               completion an amount equal to the Rent (including index- linkage
               differentials) for the aforesaid time period. The aforesaid
               payment is stipulated and agreed to as fixed damages agreed to in
               advance, which the parties have set by an assessment calculated
               in advance.

        5.2    The lessee is responsible and undertakes that throughout the
               period of the Finishing Work the lessee will carry liability
               insurance appropriate to the type of Finishing Work, under which
               the lessor shall be covered as an additional insured party.

        5.3    The lessee will pay the lessor the sum of _________ New Israeli
               Sheqels ($32,000 according to the representative exchange rate
               set on the actual date of payment) (plus value added tax) as a
               fee for supervising the Finishing Work. This payment will be made
               upon completion of the Finishing Work but no later than the start
               of the use of the Leased Premises. At the time of the signing of
               the present contract and as an integral part thereof, the lessee
               will sign a writ of obligation worded as in APPENDIX E to the
               present contract, whereby the lessee accords a right of refusal
               to Kir Hed Construction and Development Co., Ltd., a company
               affiliated with the lessor, to carry out the Finishing Work for
               it. Should the lessee entrust the Finishing Work to Kir Hed,
               Ltd., the lessee will be exempt from payment of the supervision
               fee as in section 5.3 above.

        5.4    Until the completion date of the Finishing Work the lessor shall
               complete construction of those parts of the Building necessary
               for the lessee to make reasonable use of the Leased Premises. The
               lessee affirms that is aware that gardening work and development
               work around the Building (including preparation of parking lots)
               will continue until the date of the completion of the Finishing
               Work. A delay of up to 60 days in completion of the gardening and
               development work shall not be considered to be a delay.

6.      TERM OF THE LEASE

        6.1    The lessor hereby leases to the lessee and the lessee hereby
               leases from the lessor the Leased Premises for a period beginning
               on the date when the Leased Premises are made available to the
               lessee to carry out the Finishing Work (hereinafter "THE DAY OF
               HANDOVER OF POSSESSION") and concluding on December 31, 2005
               (hereinafter "THE TERM OF THE LEASE"). The lessee shall be
               entitled to enter the Leased Premises to carry out

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               Finishing Work from the date of the signing of the present
               contract and pursuant to compliance with all of the conditions
               stated in section 5 above, on condition that the Rent for the
               first period of the Tenancy has been paid and a bank Guarantee
               conveyed as stated in section 7.5 below.

        6.2    The term of the present contract shall be extended for an
               additional five years, to begin immediately after the end of the
               Term of the Lease (hereinafter "THE TERM OF EXTENSION OF THE
               LEASE"), unless the lessee notifies the lessor in writing at
               least six months before the end of the Term of the Lease that it
               desires not to extend the Term of the Lease.

               Should the Tenancy be extended as stated in the present
               subsection above, all of the provisions of the present contract
               shall apply to the Term of Extension of the Lease as well, except
               for the lessee's right to extend the lease for another period,
               such that in no case shall the Tenancy extend beyond December 31,
               2010 (10 years).

        6.3    The lessee undertakes to appear at the Leased Premises on the Day
               of Handover of Possession and to take possession of the Leased
               Premises. Starting on the Day of Handover of Possession the
               lessee shall be able to use the parking facility of the Building
               (for payment) and shall have access to and from the Leased
               Premises. The lessor shall be entitled to postpone completion of
               work on the parking facility as required to permit parking in it
               to no later than the day of the completion of the Finishing Work.

        6.4    Subject to what is stated in section 9.1 below, the lessee shall
               not be entitled to terminate the Tenancy under the present
               contract before the end of the Term of the Lease or, as may be
               applicable, before the end of the Term of Extension of the Lease.
               Should the lessee stop using the Leased Premises or vacate them
               before the end of the Term of the Lease or, as may be applicable,
               before the End of the Term of Extension of the Lease, this shall
               not release the lessee from fulfilling its obligations under the
               present contract, in whole or in part.

        6.5    A "tenancy year" for the purposes of the present contract means a
               period of twelve Gregorian months beginning on January 1 of any
               calendar year and concluding on December 31st of the calendar
               year following it.

7.      RENT

        7.1    In consideration of the Tenancy, the lessee undertakes to pay the
               lessor Rent as stated in the present section 7 (hereinafter "THE
               RENT").

        7.2    The Rent for each month of Tenancy shall be the amount of NIS
               106,676 plus value added tax (one hundred six thousand six
               hundred seventy- six New Israeli Sheqels) [$21,420 U.S. plus
               $4,500 U.S. for 50 parking spaces] according to the
               representative U.S. dollar exchange rate known on November 12,
               2000, for each of the months of Tenancy. This Rent shall be
               linked to the index pursuant to the terms of section 7.3 below.
               The aforesaid notwithstanding, it is agreed that the lessee shall
               not be

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               liable for Rent on account of the period from the day of the
               signing of the present contract until January 1, 2001. The Rent
               shall be raised in real terms by 7.5% every 30 months of Tenancy.
               (Thus, for example, the Rent for the month beginning on June 1,
               2003, will be the sum of 114,677 sheqels, with this sum linked to
               the index pursuant to the terms of section 7.3 below.

        7.3    The Rent will be linked to the index according to the following
               linkage terms:

               If, on the date of payment of any sum whatsoever on account of
               the Rent, it transpires that the New Index last published before
               that payment (hereinafter "THE NEW INDEX") rose above the index
               published on October 15, 2000, which is 106.1 points (hereinafter
               "THE BASE INDEX"), the lessee shall pay the lessor that sum,
               augmented proportionally to the rise of the New Index over the
               Base Index. Should the New Index decline from the Base Index, the
               Rent will be computed according to the Base Index, such that in
               no case shall the lessee pay a Rent less than the Rent computed
               on the basis of the Base Index.

               For the purpose of the present contract, "the index" means the
               Consumer Price Index (cost of living index) including fruits and
               vegetables published by the Central Bureau of Statistics and
               Economic Research, and including that index even should it be
               published by some other official body or institution and
               including any official index that may replace it, whether based
               on the same data or not. Should a New Index published by a body
               or institution as stated be introduced and that body or
               institution fail to stipulate the ratio between it and the
               replaced index, the accounting firm __________ shall determine
               the computation of the rise in the index for the purposes of the
               present section, taking account of the aforesaid changes.

               The Rent due from the lessee in accordance with the present
               section 7, as well as the management fees stated in section 8.6
               below, shall be paid by the lessee to the lessor every three
               months of Tenancy in advance on the first of each calendar month
               on account of the three months of Tenancy beginning on that date,
               starting on January 1, 2001.

               The aforesaid notwithstanding, the Rent for the period from
               January 1, 2001, through March 31, 2001, shall be paid to the
               lessor at the time of the signing of the present contract.

               Should the first of the month be a holiday or Saturday, the Rent
               shall be paid on the first weekday following it. The lessor shall
               not be required to receive any payment whatsoever on account of
               the Rent before the specified due date.

        7.4    To all Rent payments and all other payments owed by the lessee
               pursuant to the present contract the lessee shall add value added
               tax at the rate applicable at that time and shall pay it to the
               lessor on the date of each payment as stated. A tax invoice on
               account of each payment as stated

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               shall be conveyed to the lessee within 14 days of the date of
               each payment as stated.

        7.5    To Guarantee payment of the Rent and fulfillment of all other
               undertakings by the lessee under the present contract, including
               to Guarantee vacation of the Leased Premises by the lessee on the
               date stipulated by the present contract, the lessee shall convey
               to the lessor at the time of the signing of the present contract
               an unconditional index- linked bank Guarantee in the amount of
               NIS 903,560, with this sum linked to the index according to the
               terms of section 7.3 above, and worded as in Appendix B
               (hereinafter "THE GUARANTEE") [an amount equal to the Rent for 6
               months of Tenancy plus management fees and value added tax]. The
               Guarantee shall be valid for twelve months and shall be extended
               from time to time no later than 30 days before its expiration for
               twelve additional months, in such manner that it shall be in
               force throughout the Term of the Lease (and as relevant, the Term
               of the Extension of the Lease) and for 60 days thereafter. The
               lessor shall be entitled to seek to invoke the Guarantee if the
               Guarantee is not extended on the dates stated, without derogating
               from the right of the lessor to seek to invoke the Guarantee in
               the case of a breach of any of the lessee's undertakings under
               the present contract. The lessor shall convey to the lessee
               written notification 7 days before acting to invoke the Guarantee
               as stated. The lessee undertakes that on the dates when the Rent
               is updated as stated in section 7.2 above it will increase the
               amount of the Guarantee as may be required, so that the Guarantee
               shall also be in an amount equal to six months' Rent plus
               management fees and value added tax.

        7.6    The parties agree that for the purposes of the present contract
               the gross area of the Leased Premises (including the proportional
               share of the common areas in the Building) shall be considered to
               be 2,142 square meters.

8.      OTHER PAYMENTS

        8.1    All municipal and central government Taxes, fees, rates, and
               compulsory levies (hereinafter "TAXES") (except for property tax
               and compensation fund) that may be levied on the tenant of the
               Leased Premises and on account of the parking spaces as stated in
               section 15.1 before, directly or indirectly, for the Term of the
               Lease shall be borne by the lessee and paid by it on the dates
               specified by law for their payment to the authorities. All
               compulsory payments incumbent upon the owners of a property (and
               not on the tenant) shall be borne by the lessor and shall be paid
               by it. To eliminate doubt it is agreed that the lessee shall not
               be required to pay development and improvement levies on account
               of the Building (nor shall it bear them through the Building
               management company).

        8.2    The lessee undertakes to be responsible throughout the Term of
               the Lease for all payments and expenses on account of
               electricity, water, and any other utility that may be supplied to
               the Leased Premises (including expenses for electrical power for
               the air conditioning system for the Leased Premises). The lessee
               undertakes that a water meter and electric

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               meter will be installed before the date of its entry to the
               Leased Premises and undertakes to sign contracts for the supply
               of electricity and water as stated. The cost of installation of
               the aforesaid meters shall be borne by the lessee. In the event
               that separate meters are not installed for the aforesaid
               utilities, the lessee shall pay the lessor and/ or pursuant to
               its directives its share in the payments for the aforesaid
               utilities according to a ratio to be set by the lessor and/ or by
               the management company stated in section 8.6 below.

               It is hereby clarified that use of the air- conditioning systems
               in the Leased Premises is limited to the proportional share of
               the Leased Premises in the Building. Should the lessee require
               enlargement of the air conditioning system in the Leased
               Premises, it will be the lessee's responsibility to do so itself
               and at its own expense.

        8.3    All Taxes and payments that may be owed to the municipality and/
               or the central government and/ or any other body on account of
               the conduct of the lessee's business in the Leased Premises,
               including business tax, sign tax, fees, and licenses, shall be
               the responsibility of the lessee alone and shall be paid by it.

        8.4    The lessor shall be entitled but not required to make any payment
               that according to the provisions of the present contract are the
               responsibility of the lessee, after it has provided written
               warning to the lessee to pay it and the lessee has failed to do
               so. In this case the lessee shall reimburse the lessor for any
               sum paid by it as stated, immediately upon the lessor's first
               request, plus linkage differentials and interest, or, at the
               lessor's option, plus delinquent interest computed according to
               section 10.1 below.

        8.5    During the Term of the Lease the lessee shall be responsible for
               its relative share of the routine maintenance expenses of the
               Leased Premises, including insurance on the structure of the
               Leased Premises, and for a proportional share of expenses for the
               regular upkeep and maintenance of the common areas of the
               Building, including, and without derogating from the generality
               of the aforesaid, its share of the expenses for management,
               operation, repair, upkeep, refurbishing, maintenance (including a
               depreciation fund), cleaning, lighting, security, gardening, and
               insurance for the common areas of the Building and for the
               technical installations in the Building such as elevators, air
               conditioning installations, electricity, entrance floors,
               stairwells, plumbing, water, sanitation, and other actions that
               the management company may choose to manage, implement, or
               handle, such as the expenses for an information, reception, and
               security desk; security center; central power room; fire
               detection and extinguishing equipment; and the like (hereinafter
               "THE SERVICES"). To eliminate doubt it is stated that the
               aforesaid shall apply, mutatis mutandis, to parking spaces as
               well.

               The "proportional share" means the ratio of the area of the
               Leased Premises (including the parking spaces) to the area of all
               parts of the Building intended for rental or sale.

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               For the purpose of dividing electric bills on account of the
               central air conditioning systems, the proportional share of the
               lessee shall be computed on the basis of the actual use
               proportional to all actual users of the system, as determined by
               the lessor.

        8.6    The lessee affirms that it is aware that the lessor intends to
               manage the Building or any part thereof on its own or through the
               agency of a management company (hereinafter "THE MANAGEMENT
               COMPANY"), or in any other way, at the exclusive discretion of
               the lessor. Should a Management Company manage the Building, the
               lessee shall pay its share in the expenses of the Management
               Company on a basis of cost plus 15%; that is, the tenants of the
               Building will cover all the expenses of the Management Company
               (including, but without derogating from the generality of the
               aforesaid, overhead and financing costs plus a profit of 15%.

               It is made clear that financing costs on account of delinquency
               in payments by a tenant of the Building to the Management Company
               shall be borne by that tenant.

               It is clarified that in consideration of the aforesaid amount the
               Services enumerated in the Principles of Management appendix
               attached to this contract as an integral part thereof and labeled
               APPENDIX C shall be provided.

               The lessee undertakes to cooperate with the Management Company
               and to comply with its instructions and the instructions of
               anyone acting on its behalf.

        8.7    At the lessor's request the lessee will sign a management
               agreement with the lessor or with the Management Company that
               manages the Building, worded in accordance with the Principles of
               Management appendix, Appendix C.

        8.8    The lessor pledges that the Management Company will act
               efficiently and faithfully to the benefit of the tenants and
               owners of areas in the Building.

9.      OCCUPANCY OF THE LEASED PREMISES DURING THE TERM OF THE LEASE

        9.1    The lessee hereby undertakes not to transfer its rights under the
               present contract or any part thereof to some other party or
               parties in any fashion whatsoever, directly or indirectly; and
               not to deliver or transfer the Leased Premises or any part
               thereof to another party or parties in any fashion whatsoever;
               and not to permit use of the Leased Premises or any part thereof
               for any period whatsoever and in any manner to any other party or
               parties; and not to include another party or parties in the
               occupancy of the Leased Premises or any part thereof; and not to
               include any other party or parties in occupancy of the Leased
               Premises or any part thereof and not to grant to anyone
               whatsoever any right in the Leased Premises as licensee, for
               consideration or not for consideration, other than in the manner
               and in

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               accordance with the terms enumerated in the continuation of this
               subsection below.

               The aforesaid notwithstanding, it is agreed that the lessee shall
               be entitled to sublet a portion of the Leased Premises subject to
               compliance with the totality of the terms below.

               (i)    The identity and business of the subtenant have been
                      approved in advance by the lessor in writing.

               (ii)   The subtenant accepts all of the obligations under the
                      present contract that relate to maintenance and use of the
                      Leased Premises.

               (iii)  Keryx Israel, Ltd., remains responsible for all
                      undertakings of the lessee under the present contract.

               Should the entire Leased Premises be sublet as stated, the option
               stated in section 6.2 shall be void.

        9.2    The lessee undertakes to maintain the Leased Premises and its
               systems (including plumbing, electricity, lighting, and air-
               conditioning [not including the central air conditioning system
               on the roof of the Building, which will be maintained by the
               Management Company]) in sound working order, to perform regular
               upkeep and maintenance work, to refrain from causing damage or
               harm to them or to any of their installations, and to be
               responsible for and to repair immediately and at its own expense
               any damage that may be caused to the Leased Premises and its
               systems by it and/ or by its visitors and/ or by its customers
               and/ or by its employees and/ or by anyone who may enter the
               Leased Premises.

        9.3    The lessee undertakes not to make any interior and/ or exterior
               modifications to the Leased Premises and not to make any addition
               to or to destroy any part of the Leased Premises and/ or any of
               its installations without prior written consent from the lessor;
               the lessor shall be entitled to prevent the commission of any
               such act and to remove any modification or addition made in
               contravention of the present section. The lessor shall not turn
               down a request by the lessee to make an interior modification as
               stated other than for reasonable cause. Breach of this section by
               the lessee shall entitle the lessor, in addition to any remedy
               that may be available to it by law, to cancel the contract; and
               in this case the lessor shall be entitled, should it choose this
               right, to have all additions, repairs, and modifications made in
               breach of the contract belong to the lessor without being
               obligated to pay for them.

        9.4    Should the lessor agree in writing to a request by the lessee to
               make modifications to the Leased Premises, the lessee, at the end
               of the Term of the Lease, shall restore the Leased Premises to
               the condition in which it was on the day of completion of the
               Finishing Work, subject to reasonable wear and tear, unless the
               lessor notifies the lessee of its desire that the modifications
               or some of them remain in place, and the lessee shall not be able
               to demand and/ or to receive any compensation or payment for
               them.

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               The aforesaid notwithstanding, the lessee shall be entitled, at
               the conclusion of the Term of the Lease, to remove the air-
               conditioning units (fan- coolers in rooms and additional external
               units [if installed]) that it may have installed in the Leased
               Premises. The lessee undertakes to restore the status quo ante,
               including drop ceilings, electrical wires and conduits, touch-up
               painting, waterproofing and insulation repairs, and the like, in
               accordance with the lessor's instructions, after the removal of
               the air- conditioning units.

        9.5    The installation and operation of electrical equipment,
               telephones, and communications equipment in the Leased Premises
               and the passage of electrical wiring for the operation of the
               aforementioned equipment that may cause induction and/ or
               emissions is contingent upon prior written consent by the lessor
               and subject to instructions that may be issued by the lessor and
               also, if required, upon receipt of approval from the Ministry of
               Communications and/ or Bezeq, Ltd., for the equipment and its
               installation.

        9.6    To eliminate doubt it is stated that the lessee is not entitled
               to install any equipment whatsoever outside the Leased Premises.
               The aforesaid notwithstanding, with regard to equipment or
               systems that are essential for the lessee's use of the Leased
               Premises the lessee shall be entitled to request that the lessor
               permit their installation at its the lessee's own expense,
               providing full details of the components of the system, and the
               lessor shall be entitled to approve the installation of such
               equipment and systems as well as their location or to disallow
               their installation, as relevant, and to set the payment due it
               for making the space available for the installation of the
               aforesaid system.

        9.7    It is agreed that the lessor shall be entitled to instruct the
               lessee to change the location in the Building of any system as
               stated to some other location in the Building and/ or the lot if
               and when the system creates any interference whatsoever to any
               tenant of the Building. Should this instruction result from the
               lessor's desire to build on or use the area on which the system
               is located for its own purposes, then the change of location
               shall be carried out by the lessor and at its own expense after
               provision of five days' advance notice and after having
               coordinated the method and time of transfer with the lessee. The
               lessee shall have no grounds for a claim on account of this. The
               lessee shall not use flammable gas, open flames, or method that
               gives off cooking odors in any part of the Leased Premises,
               including in a kitchenette, should there be such in the Leased
               Premises. The aforesaid notwithstanding, the lessee shall be
               entitled to use flammable gas or some other gas in the laboratory
               for laboratory purposes (but not for cooking), subject to advance
               written approval by the lessor concerning the type of gas, the
               quantity stored in the Building, and the mode of installation.
               The lessor and/ or its representative shall be entitled to enter
               the Leased Premises at any reasonable time and with advance
               coordination with the lessee to inspect the Leased Premises as
               well as to carry out repairs and work for other parts of the
               Building. The lessor shall coordinate with the lessee entry to

<PAGE>

               the Leased Premises as stated above, except in urgent cases.
               Nothing in the aforesaid shall impose any obligation whatsoever
               on the lessor to perform anything mentioned above.

               When carrying out actions as stated above, the lessor shall do
               its utmost so that any damage caused to the lessee, if damage be
               caused, shall be as minimal as possible; so that the duration of
               the work shall be as brief as possible; and so that upon
               completion of the work the lessor shall restore the Leased
               Premises to the status quo ante.

        9.8    The lessee undertakes not store any materials, tools, equipment,
               or other movable objects in the entrance or outside the Leased
               Premises, including in the elevator corridor on each story, to be
               meticulous about keeping the area around the Leased Premises
               clean, and to conduct its business exclusively within the Leased
               Premises.

        9.9    The lessee shall not be entitled to hang any signs or notices
               whatsoever on the facade of the Leased Premises or in the
               elevator corridor, including the elevator corridor on each floor,
               or on any external wall of the Leased Premises or any external or
               other part of the Building, or to install mailboxes, without the
               consent of the lessor. The lessee shall bear a proportional share
               of the cost of signs and the general mailbox unit, and the
               expense of installing signs in the lobby or on the floors on
               which the Leased Premises are located. In any signs installed in
               the Building by the lessor, the lessee shall have a share that
               reflects its share of the Building or of the relevant floors. The
               lessee shall request the lessor's consent for everything
               associated with the installation and placement in the Leased
               Premises of equipment and furnishings whose weight and/ or size
               is liable to exceed the permissible limit. The lessor shall be
               entitled to require the lessee to obtain approval from the
               Building architect or from some other engineer, as it determines.

        9.10   The lessee undertakes to fulfill and carry out any provision of
               law, regulation, order, or municipal bylaw that relates to the
               Leased Premises or to its Tenancy or use thereof, and not to do
               and not to permit to be done in the Leased Premises or in
               association with it anything that is liable to constitute a
               hazard or nuisance or to cause damage or inconvenience to the
               lessor or to the Building or to other lessees or users or to
               visitors to the Building.

        9.11   The lessee undertakes to compensate and indemnify the lessor for
               any damage or expense that may be caused the lessor on account of
               a suit brought against the lessor, whether criminal or civil, and
               on account of the need to defend itself against such a suit--to
               the extent that the stated suit stems from the lessee's failure
               to fulfill or breach of its undertakings in the present contract.
               The lessor shall notify the lessee of any suit that may be
               brought against it as stated above and shall include it in the
               direction of the defense against such a suit.

        9.12   Whereas the lessee is leasing the Leased Premises in order to use
               them for its business, including a pharmaceutical laboratory, it
               is agreed that

<PAGE>

               without derogating from anything else stated in the present
               contract, if so stated, the lessee shall be responsible for
               obtaining and undertakes to obtain all of the approvals and
               licenses required from any authority whatsoever in association
               with its activity as stated, including in association with the
               storage and use of hazardous materials, the removal of solid and
               liquid wastes, and everything else associated with its business.
               The lessee further undertakes not to keep and not to make any use
               whatsoever of laboratory animals except on rare occasions and in
               a temporary manner.

        9.13   To eliminate doubt it is stated that the Tenancy under the
               present contract does not include the balconies.

10.     DELINQUENCY IN PAYMENT

        10.1   Should the lessee be delinquent in the payment of any sum
               whatsoever that it is bound to pay the lessor pursuant to the
               present contract, the lessee shall pay the lessor, in addition to
               the delinquent amount, index- linkage differentials and interest
               at the rate then in effect at Bank Le'umi le-Israel, Ltd., for
               index- linked loans, plus 10 percent per annum, computed from the
               date on which the lessee was to have paid the delinquent sum
               until the day when it actually paid or, at the lessor's option,
               the lessee shall pay the lessor, in addition to the delinquent
               sum, interest at the maximum rate of interest in effect at Bank
               Le'umi le-Israel, Ltd., for overdrafts that exceed the approved
               credit limit in revolving debitory accounts, compounded monthly
               (hereinafter "Delinquent Interest"). The Delinquent Interest
               shall be computed for the period from the day on which the lessee
               was to have paid the delinquent sum until the date when it was
               actually paid.

        10.2   Nothing in the payment of linkage differentials and interest or
               the payment of Delinquent Interest pursuant to section 10.1 above
               shall derogate from the lessor's right to any other remedy that
               is stipulated in the present contract or in law on the grounds of
               breach of contract by delinquency in payment. Receipt of the
               stated interest shall not be construed as a waiver on the part of
               the lessor or the Management Company of any other remedy as
               stated.

        10.3   A delay in payment that does not exceed seven days shall not be
               considered to be a breach of the present contract and shall not
               entitle the lessor to interest as stated above. A delay as stated
               that exceeds seven days shall be considered to be a breach of
               contract and shall entitle the lessor, in addition to all
               remedies available to it pursuant to the present contract and
               under any law, to interest from the first day of the delinquency.

11.     LICENSING AND PERMITS

        11.1   The lessee is responsible for obtaining all licenses and permits
               required to conduct its business in the Leased Premises. A
               failure by the lessee to

<PAGE>

               obtain the stated licenses or some of them shall not serve as
               justification or grounds for the lessee to cancel the present
               contract.

               Without derogating from the aforesaid, the lessee shall be
               responsible for and undertakes to see to obtaining all approvals
               required with regard to its activity in the Leased Premises from
               the Ministry of the Environment, the Ministry of Health, the
               Jerusalem municipality, and any additional and/ or other agency
               whose approval is required for the lessee's activity in the
               Leased Premises, and to comply with any request and directive as
               stated, including in connection with the removal of liquid waste,
               the removal and disposal of solid waste, water pollution, and
               possession and storage of flammable materials, chemicals, and the
               like.

        11.2   The lessee hereby declares that before it signed the present
               contract it was given the opportunity to verify and did in fact
               verify the suitability of the Leased Premises for the purpose of
               the Tenancy and the possibility of obtaining a license to operate
               the Leased Premises for the purpose of the Tenancy.

12.     OBLIGATIONS OF THE LESSEE

        12.1   The lessee undertakes to maintain the Leased Premises throughout
               the Term of the Lease in sound and orderly condition, to avoid
               causing damage or harm to the Building or the Leased Premises or
               any of its installations, and to repair immediately and at its
               own expense any damage that may be caused to the Leased Premises.
               The lessor shall repair at its own expense any damage that may be
               caused to the Leased Premises and/ or to the Building during the
               first year of the lease as a result of faulty workmanship or use
               of defective materials. Throughout the Term of the Lease the
               lessor shall be responsible for repairing and shall repair at its
               own expense any damage to the shell of the Building that was not
               caused by acts of commission or omission on the part of the
               lessee or someone acting on its behalf and that prevents
               reasonable use of the Leased Premises.

        12.2   The lessee shall be responsible for all damages of any type and
               kind whatsoever that may be caused to the Leased Premises and/ or
               to the Building and/ or to the lessor and/ or to any third party
               that may be present in the Leased Premises and/ or in the
               Building and that stem from the lessee's acts of commission and/
               or omission, including acts of commission and/ or omission by its
               employees, guests, customers, and persons acting on its behalf
               and/ or from the conduct of its business in the Leased Premises.

        12.3   The lessor shall bear no responsibility whatsoever and no
               liability whatsoever with regard to any bodily damage and/ or
               property loss and/ or damage of any kind whatsoever that may be
               caused to the lessee and/ or to its employees and/ or to its
               customers and/ or to its visitors and/ or to any person acting on
               its behalf who may be present in the Leased Premises or en route
               to or from the Leased Premises, and the lessee assumes full
               responsibility for any damage of this sort and undertakes to
               compensate

<PAGE>

               and indemnify the lessor for any damage or loss for which it may
               be held accountable and for any expense that the lessor may have
               in connection with this.

13.     INSURANCE

        13.1   Without derogating from the lessee's responsibility as stated in
               section 12 above, the lessee undertakes to insure at its own
               expense the contents of the Leased Premises and its business and
               the additions and improvements that have been made or may be made
               to the structure of the Leased Premises and its facilities, its
               activity in the Leased Premises, at their full value on a
               replacement basis, with the amount of the insurance updated from
               time to time as necessary and against all possible, recognized,
               expected, and customary risks, with a licensed and reputable
               insurance company. Without derogating from the generality of the
               aforesaid, the lessee hereby undertakes to insure the contents of
               the Leased Premises against damage from fire, break-in, theft,
               forcible entry, or normal loss; broken glass, flood, mechanical
               failure, and water damage of any kind, all at full replacement
               value.

        13.2   The lessee also undertakes to insure at its own expense its
               activity in the Leased Premises as follows:

               13.2.1  Liability insurance on the Leased Premises and the
                       business conducted in them and on the lessee's activity,
                       to cover the liability of the lessor, the Management
                       Company, and the lessee with regard to any person on
                       account of bodily injury or monetary or property damage
                       that may have taken place in connection with the Leased
                       Premises and/ or the activity conducted in the Leased
                       Premises or in the Building and associated with the
                       lessee's business. The limits of liability of the third-
                       party insurance shall not be less than the following
                       amounts:

                      $500,000 for a single claimant in a single incident for
                      bodily damage and $2 million for multiple claimants in a
                      single incident

                      $2 million for property damage per incident and period

                      $5 million in employer's liability insurance

               13.2.2  To cover loss of profits and any consequential damages on
                       account of damage caused to the Leased Premises or their
                       contents.

        13.3   The lessee hereby undertakes to add the lessor's name (and that
               of the Management Company) as additional insured parties in the
               policies mentioned in sections 13.1 and 13.2 above. The lessee
               undertakes to deliver to the lessor, no later than two weeks
               before the start of the Term of the Lease, a certificate of
               insurance signed by the insurer on a form modeled after that in
               APPENDIX D to the present contract.

<PAGE>

        13.4   The lessee undertakes to comply with all the terms of the
               policies mentioned above in the present section, to pay the
               premiums on time, and to see to it that the policies are renewed
               and are in full force throughout the Term of the Lease.

        13.5   It is hereby agreed and stated explicitly that no responsibility
               whatsoever of any type or kind shall be borne by the lessor and
               the Management Company vis-a-vis the lessee on account of any
               damage that may be caused to the Leased Premises or to its
               content or to a third party for any reason whatsoever, whether
               the cause of the damage or malfunction is known or unknown, and
               the lessee shall see to it that an explicit clause is added to
               the insurance policy whereby the insurer explicitly waives any
               right of subrogation or any other right in law to have recourse
               to the lessor and/ or to the Management Company in a claim for
               subrogation or refund or indemnification on account of direct or
               indirect damage that may be incurred on account of the lessor,
               should such damage be incurred.

        13.6   The lessor's right of inspection and its exercise or non-exercise
               of its right to see the policies and demand updates, riders, or
               modifications shall not impose upon it any responsibility
               whatsoever with regard to the policies, their nature, and their
               validity, or with regard to absence thereof.

        13.7   The lessor shall take out, on its own or through the Management
               Company, insurance on the Leased Premises along with the other
               areas of the Building in its ownership, including the common
               areas of the Building, comprehensive insurance (structure only,
               not including modifications or any other changes that may be made
               to the Leased Premises), and third- party insurance against
               property damage and/ or bodily damage, under the terms and with
               the restrictions as may be stipulated by the lessor from time to
               time. The lessee shall pay the lessor and/ or the Management
               Company, as relevant, its proportional share of the cost of the
               insurance, proportional to the area of the Leased Premises,
               including parking spaces, in the total areas covered by the
               aforesaid insurance.

               To eliminate doubt it is explicitly agreed that the taking out of
               the aforesaid insurance policies shall not detract or derogate
               from the lessee's responsibility for the integrity of the Leased
               Premises and from its undertaking to return it to the lessor at
               the end of the Term of the Lease free of injury or damage; the
               lessee undertakes to pay any amount that may be required to
               repair the structure of the Leased Premises and that is not paid
               by the insurers for any reason whatsoever.

        13.8   The lessee hereby undertakes not to perform or allow any other
               party to perform any act of commission or omission that is liable
               to increase in any fashion whatsoever the lessor's insurance
               costs for the Building. Should the lessor or the Management
               Company be required to pay additional premiums in excess of the
               norm and as a direct result of an act of commission or omission
               on the part of the lessee and/ or by virtue of the nature of its
               activity in the Leased Premises, the lessee shall pay the lessor
               or the Management Company, as relevant, the stated increment

<PAGE>

               immediately upon the first request made by the lessor or by the
               Management Company. It is hereby agreed that for this purpose the
               presence of a biopharmaceutical laboratory in the Leased Premises
               shall not be considered to increase the insurance premiums. With
               regard to laboratory animals, the insurance on the structure will
               include no coverage for any damage that may be caused on account
               of laboratory animals and the lessee shall bear full
               responsibility for this.

14.     MODIFICATIONS OR ADDITIONS BY THE LESSOR

        14.1   The lessor shall be entitled at any time, on its own initiative
               and at its own discretion, to make changes to the Building and to
               initiate a change in the City Building Plan relating to the
               Building and to request concessions and a permit for another or
               exceptional use for any part thereof, including, but without
               derogating from the generality of the aforesaid, in connection
               with the use and construction of the balconies of the Building,
               provided that such a modification does not include a modification
               of the Leased Premises themselves. The lessee undertakes not to
               oppose any such change or request.

        14.2   The lessor is entitled, without requiring any consent whatsoever
               on the part of the lessee, to make any modification or addition
               to the Building, all at the sole discretion of the lessor and as
               it may see fit from time to time, provided that nothing in the
               execution of the change or addition shall constitute unreasonable
               interference with the use of the Leased Premises.

        14.3   Without derogating from the generality of what is stated in
               sections 14.1 and 14.2 above, or in any other section of the
               present contract, it is hereby explicitly stated by the lessee
               that the lessor is entitled at any time to add and/ or to
               construct an additional story on the Building and/ or to carry
               out any construction work and/ or modifications and/ or additions
               to the Building; and to make any use of the additional area or
               parts thereof that may be constructed, without any restriction
               and with no need to obtain any consent whatsoever on the part of
               the lessee, all at the sole discretion of the lessor; including
               leasing, selling, and the like; and the lessee undertakes to
               permit the lessor to do so and not to interfere with it in any
               form or manner. The lessor shall carry out the aforesaid
               activities in such a manner that nothing in these activities
               shall constitute continuing and unreasonable interference, in the
               circumstances that apply, with the lessee's normal conduct of the
               business in the Leased Premises. The aforesaid shall apply to a
               Building addition using light construction only. Should the
               lessor wish to add a story or stories to the Building using
               conventional construction methods, the lessor shall not carry out
               the stated construction without written consent from the lessee,
               which shall not withhold it for other than reasonable cause.

15.     PARKING FACILITY

        15.1   The lessee declares that it is aware that the Building includes a
               parking facility intended for use by the tenants of the Building
               and by the public,

<PAGE>

               but the parking facility will not be included in the common areas
               of the Building. The lessee leases from the lessor 50 parking
               spaces in the parking facility in consideration of the Rent
               stipulated in section 7.2 above. The aforesaid and section 7
               notwithstanding, the lessee shall not owe Rent for the parking
               spaces for the period before the start of the actual use of all
               or some of the parking spaces, or for three months beginning on
               November 12, 2000 (Memorandum of Understanding), whichever is
               earlier. Should actual use be made of only some of the parking
               spaces, payment shall be made only for the pro rata share of the
               payment on account of them.

        15.2   To eliminate doubt it is hereby stated that the right shall be to
               park a specific vehicle and to a specific fixed parking space (to
               be determined by the lessor and/ or the Management Company). The
               hours of operation of the parking facility and the other terms of
               use of the parking facility shall be determined from time to time
               by the operator of the parking facility, and the lessee
               undertakes to use its parking spaces subject to the aforesaid
               terms. In addition to any other payment under the present
               agreement, the lessee undertakes to leave a deposit with the
               lessor for the remote- control devices that will be provided to
               it in connection with use of the parking facility.

        15.3   Use of the parking facility is on the exclusive responsibility of
               the lessee. The lessor and/ or the Management Company and/ or any
               person acting on their behalf shall bear no responsibility
               whatsoever for any loss or damage to the vehicles that enter the
               parking facility or to objects inside them. The lessee undertakes
               to indemnify the lessor and the Management Company and any person
               acting on their behalf for any damage or expense that may be
               caused them should they be sued to compensate any person
               whatsoever for loss or damage as stated. The lessee undertakes
               that its employees' vehicles that will be parked in the parking
               facility will be insured for their full value.

16.     VACATING THE PREMISES

        16.1   At the end of the Term of the Lease or the end of any extension
               of the Term of the Lease, should there be such, or with the
               abrogation of the present contract for any cause whatsoever, the
               lessee undertakes to vacate the Leased Premises and to hand over
               possession of it to the lessor, with the Leased Premises free of
               any person or object belonging to the lessee, in clean and
               orderly condition, and in the condition that the Leased Premises
               were in after the completion of the Finishing Work, except for
               reasonable depreciation and wear and tear and except for those
               changes and additions that are to be left in the Leased Premises
               at the lessor's request, as stated in section 9.4 above.

        16.2   Should the lessee fail to vacate the Leased Premises on the date
               stated in section 16.1 above, then, in addition to the lessor's
               right to bring suit for vacation of the Leased Premises and in
               addition to any other right that the lessor may have under the
               present contract or under any law, the lessee shall pay the
               lessor, on account of the period from the time when it was to

<PAGE>

               have vacated the Leased Premises until the date when it actually
               vacated the Leased Premises, a sum equal to three times the Rent
               (including linkage differentials) that would be paid under the
               present contract had the Tenancy been extended under the terms of
               the present contract. The stated payment is stipulated and agreed
               upon as an appropriate usage fee and/ or as damages fixed and
               agreed to in advance, which the parties have set by an assessment
               calculated in advance.

               Nothing stated in the present section above shall endow the
               lessee with a right to continue to occupy the Leased Premises
               against payment of the agreed upon compensation.

17.     REMEDIES AVAILABLE TO THE LESSOR ON ACCOUNT OF BREACH OF CONTRACT

        17.1   Without derogating from what is stated below in the rest of
               section 17 and the specific remedies that appear in the present
               contract, the provisions of the Contracts Law (Remedies for
               Breach of Contract) 5731-1970 shall apply to a breach of the
               present contract.

        17.2   Should the lessee fail to maintain the Leased Premises in sound
               condition and/ or fail to repair what requires repair in the
               Leased Premises and/ or fail to return the Leased Premises to the
               lessor at the end of the Term of the Lease in sound condition as
               stated in the contract and/ or should any damage whatsoever be
               caused to the Leased Premises during the Term of the Lease and
               not have been repaired by the lessee, then in addition to any
               other right that the lessor may have in such a case pursuant to
               the provisions of the present contract and/ or in accordance with
               any legal provision, the lessor shall be entitled to carry out,
               after having warned the lessee and having specified in the
               warning a reasonable time for repair and after the lessee has
               nevertheless not repaired what requires repair within the time
               specified above, to carry out, at the lessee's expense, any
               repair and/ or to take any action whatsoever that it may deem
               appropriate for repairing the damage and/ or for restoring the
               status quo ante, and the lessee undertakes to pay the lessor,
               immediately upon demand, all sums that the lessor has expended on
               actions it took in accordance with the present section above.

        17.3   Should the lessee breach its obligations or any part thereof
               vis-a-vis the Management Company and/ or under the management
               agreement, this shall be deemed to be a breach of the present
               contract.

        17.4   Any omission, delay, or waiver by a party in exercising any of
               its rights under the provisions of the present contract shall not
               be considered to be a waiver, debarment, consent, or
               acknowledgement on its part and it shall be able to use its
               rights under the present contract at any time it wishes without
               being debarred from doing so.

        17.5   Should the lessee breach the contract in its entirety or any of
               its sections and fail to amend the breach within a reasonable
               time, despite having been warned in writing in a warning that
               specifies a reasonable time for amending the breach; and in any
               case in which the lessee fails to pay the

<PAGE>

               Rent and/or any sums and/or other payments or any part thereof
               owed by it under the present contract on time, nor within seven
               days of the date of the written demand that it amend the
               breach--the lessor shall be entitled, without derogating from all
               other rights granted it by law and/ or under the present
               contract, to cancel the contract and/ or to specify a date for
               vacation of the Leased Premises, as it sees fit, and/ or to act
               to vacate the Leased Premises, and in this case the contract will
               be annulled as of the date specified by the lessor and the lessee
               shall vacate the Leased Premises no later than this date. Should
               the lessee fail to do so, the lessor shall be entitled to act at
               its discretion to vacate the Leased Premises, including removing
               objects from the Leased Premises and placing them in storage and
               changing the locks on the Leased Premises.

        17.6   In any case of the abrogation of the present contract as a result
               of its breach by the lessee, the lessor shall be entitled to all
               additional remedies available to it by law on account of breach
               of contract, including the remedy of monetary compensation, a
               prohibitory injunction, and a mandatory injunction. Everything
               stated in the present contract and in addition thereto
               notwithstanding, in the case of a breach of contract by the
               lessee on account of which the lessee has been evicted from the
               Leased Premises before the end of the Term of the Lease, the
               lessee shall pay the lessor reasonable monetary compensation for
               the period from the date of eviction until the end of the Term of
               the Lease, in an amount equal to the Rent lost by the lessor on
               account of the abrogation, whether for the entire balance of the
               Term of the Lease (or the balance of the Term of Extension of the
               Lease, as relevant) or for a period until the Leased Premises are
               let to another lessee, and after that until the end of the Term
               of the Lease or to the end of any term of Extension of the Lease,
               as relevant, on account of the loss of Rent, if any, or on
               account of a lower Rent paid by the other lessee, but not less
               than three months' Rent, plus value added tax. This sum is set by
               the parties as damages fixed and assessed in advance with no need
               to prove damage, after the parties have made a cautious and
               deliberate assessment of the damage that may be caused to the
               lessor on account of a breach by the lessee as stated.

18.     MISCELLANEOUS

        18.1   Any equipment that may be installed on the roof of the Building
               shall be equipped with shock absorbers of reasonable size for the
               equipment installed.

        18.2   The lessor pledges that access to the roof on the third floor
               shall not be through the Leased Premises.

        18.3   The lessee declares that it is aware that work on the first floor
               of the Building has begun and it undertakes to complete any work
               planned to be carried out on the floor of the second floor and
               the ceiling of the first floor no later than 30 days from the
               signing of the present contract. The lessee declares that it is
               aware that after this date it will not be permitted to carry out
               work on the ceiling of the first floor and that any damage and/
               or delay in the completion of the Finishing Work that may delay
               completion of the

<PAGE>

               work for the lessee of the first floor of the Building shall be
               borne by the lessee.

        18.4   The lessee declares that it is aware that for the purpose of a
               tenanting certificate it may be required to complete the
               sprinkler system in the Leased Premises, and it undertakes to do
               so no later than 14 days from receipt of a request from the
               lessor and to submit certification from the Standards Institution
               of Israel that affirms the soundness of the system for
               presentation to the authorities by the lessor.

        18.5   All payments that the lessee is required to make to the lessor
               under the present contract shall be made by the lessee to the
               lessor by a standing order or by a bank transfer to the lessor's
               account or in any other way as the lessor may instruct the lessee
               from time to time.

        18.6   The lessor is entitled to sign over and/ or to pledge its rights
               in the Building and/ or in the Leased Premises, in whole or in
               part, to transfer a partial or full leasehold, at its sole
               discretion, without requiring the consent of the lessee;
               similarly, the lessor shall be entitled to pledge the present
               contract in whole or in part, to sign over its rights in it to
               other parties, to transfer it in whole or part, in whatever
               fashion and manner the lessor may deem to be appropriate from
               time to time, whether in order to obtain financing or for any
               other purpose, all at the sole discretion of the lessor; the
               lessee hereby explicitly agrees to assume and to comply with all
               provisions of this contract vis-a-vis any other entity, if any,
               that may come in place of the lessor. Such a mortgage, lien,
               endorsement, or transfer shall have no power to derogate from the
               rights of the lessee under the present contract or to add to its
               obligations according to it and any transferee to which the
               lessor may transfer its rights as stated above shall replace the
               lessor in everything associated with the present contract.

        18.7   The lessor shall be entitled to build a blocking wall at the
               boundary between the lot and the lot located southeast of the
               lot, and the lessee shall have no right to file a claim on these
               grounds.

        18.8   Subject to any explicit contravening provision in the present
               contract, the parties hereby agree that the present contract is
               personal and cannot be transferred by the lessee in any fashion
               whatsoever.

        18.9   The terms of the present contract reflect what has been
               stipulated between the parties in full and annul any prior
               contractual agreements, promises, representations, and
               undertakings made by the parties before the signing of the
               present contract, if any, whether written or oral. Any amendment
               of the present contract and any supplement to it must be executed
               in writing and signed by the parties.

        18.10  The lessee declares that it is aware that the name of the
               Building is Beit Hadarim and that the lessor is entitled to
               change the name of the Building as it may see fit, at its sole
               discretion.

19.     ADDRESSES AND NOTICES

<PAGE>

        19.1  The cost of stamping the present contract shall be borne and paid
              by the lessee.

        19.2  The addresses of the parties for the purpose of the contract are
              as follows:

              Lessor:RMPA Har Hotzvim, Ltd., House

              Lessee:The Leased Premises

        19.3  Any notice that may be sent by one party to the other pursuant to
              the present contract shall be sent by registered mail or by fax
              or shall be delivered by hand and shall be considered to have
              been delivered in the reasonable time in which the stated notice
              should have reached the addressee.

IN WITNESS WHEREOF THE PARTIES HAVE AFFIXED THEIR SIGNATURES AT THE PLACE AND ON
THE DATE SPECIFIED AT THE START OF THE CONTRACT.

/s/ Amos Hadar                                        /s/ Morris Laster
-----------------------                               ------------------------
Lessor                                                Lessee

<PAGE>

                                  BEIT HADARIM:
                 TECHNICAL SPECIFICATION FOR THE BUILDING SHELL

1.      Polished stone facing plus windows and curtain walls according to the
        architect's plans and what currently exists on the site

2.      Floors

        a.     Smoothed concrete floor

        b.     Concrete and/ or prefab ceilings

3.      Elevators with a rated capacity of one ton each

4.      Aluminum windows and curtain walls made of various profiles in natural
        matte silk finish as currently exists in the Building and in accordance
        with the decision of the lessor's consultants, blue anti-sun glazing as
        exists at the site

5.      Infrastructure for electrical connection by the electric company.
        Request (of the electric company) for electrical hook-up and cost of
        installation of meters if any. Capacity of the connection for each
        floor: 3 x 63 amperes.

6.      Complete public electrical system, including:

        a.     Lighting in public areas, lobbies, and parking facilities, and
               exterior lighting

        b.     Electric power to operate the Building systems (elevators,
               electric gates, pumps, switchboards, and the like)

        c.     Power feed for the central air conditioning system

7.      Air conditioning: central air conditioning system with two 90- ton
        chillers and auxiliary systems including fresh air ducts and water pipes
        for each floor

8.      Telephony infrastructure satisfying the requirements of Bezeq, Ltd.

        Infrastructure on each story connected to the main communications room

9.      One lavatory will be built in the public area for use by the guard or
        custodian.

10.     Water hook-up: a water hook-up will be installed in the utility cabinet
        on each floor. Infrastructure will be installed on each story for a
        sprinkler system. This infrastructure will be connected to the main
        system of the Building.

11.     Sanitation hook-up: sanitary plumbing infrastructure at many points in
        the Building as currently exists.

<PAGE>

                                   APPENDIX C
                     PRINCIPLES OF THE MANAGEMENT AGREEMENT

1.      DEFINITIONS

"The Management Company"          The lessor and/ or a company acting on its
                                  behalf and/ or in its name

"Management and                   All sums that the lessee is required to pay to
Maintenance Fees"                 the Management Company (hereinafter "the
                                  Management Agreement")

"Public Areas"                    This means all areas within the boundaries of
                                  the lot, including, and without derogating
                                  from the generality of the aforesaid, all
                                  structures, additions, or improvements that
                                  may be made from time to time, the outside
                                  and/ or underground parking facilities,
                                  gardens, roofs, passageways, stairwells,
                                  entrances and exits, basements, internal
                                  streets, sidewalks, utility rooms, lavatories,
                                  air- conditioning, loading and unloading
                                  facilities, elevators, stairs, stairwells,
                                  escalators, and any other area within the
                                  boundaries of the lot on which the project has
                                  been erected that is accessible to the general
                                  public and/ or that will be made accessible to
                                  it and/ or those areas that serve and/ or will
                                  serve all the tenants in the project or most
                                  of them, such as transformer rooms, garbage
                                  compactors, loading and/ or unloading and/ or
                                  storage cellars, the offices of the Management
                                  Company, and shelters, all except for those
                                  parts of the Building and the lot intended for
                                  sale and/ or rental.

2.      OBLIGATIONS OF THE MANAGEMENT COMPANY

        a.     The Management Company undertakes to manage, maintain, and
               operate the Building.

               The lessee undertakes not to carry out itself and/ or through the
               agency of another party acting on its behalf the services and
               other activities entrusted to the Management Company under the
               Management Agreement and agrees that these services and
               activities will be carried out exclusively by the Management
               Company.

        b.     Without derogating from the generality of the aforesaid, the
               Management Company shall be entitled to deal, inter alia, with
               the following matters that are included in the management,
               maintenance, and operation of the Building and the lot:
<PAGE>

               (1)    Cleaning and lighting of the public areas and a
                      receptionist in the lobby 24 hours a day

               (2)    Air-conditioning of those public areas in which air-
                      conditioning is possible and appropriate

               (3)    Gardening work on the lawns and plantings in the public
                      areas

               (4)    Installation of equipment and objects that will serve
                      visitors to the lot

               (5)    Maintenance and upkeep of the public areas and of the
                      equipment and objects that serve the Building and/ or the
                      tenants and/ or those with rights in the Building, all or
                      some of them, to the extent that this relates to equipment
                      that is not owned by and/ or the responsibility of any of
                      the tenants, including, inter alia, generators, gas and
                      fuel tanks, the sanitary, plumbing, electrical, drainage,
                      and lighting systems, and the elevators and escalators in
                      the public areas of the Building

3.      RIGHTS OF THE MANAGEMENT COMPANY

        a.     In order to carry out its obligations under the Management
               Agreement, the Management Company is entitled, inter alia, at its
               sole and absolute discretion, and in such conditions as it may
               deem appropriate:

               To maintain offices in the Building and/ or in any other place
               and to employ managers, clerks, accountants, bookkeepers,
               lawyers, laborers, artisans, professionals, consultants,
               engineers, architects, contractors, subcontractors, and other
               workers, all as it may deem essential and at its sole discretion.
               Such employment shall be exclusively with reference to the needs
               of the tenants and owners of areas in the Building.

        b.     To take out insurance on the physical structure of the project
               against physical loss or damage on account of fire, lightning,
               explosion, earthquake, riots, terrorism, strikes and wanton
               damage, flood and water damage, electricity, and other natural
               disasters, as well as against any other risk that the Management
               Company may deem necessary, in amounts or with no cap on the
               amount, as may be determined by the Management Company. The
               insurance as stated shall include a clause waving the right of
               subrogation vis-a-vis the tenants on account of damage caused by
               them unintentionally to the structure of the Building.

        c.     To take out third- party liability insurance covering the
               liability of the lessor, the Management Company, and the lessee
               against any third party whatsoever in amounts or with no cap on
               the amount, as the Management Company may deem warranted from
               time to time, in the public areas that are not part of the Leased
               Premises.

               The policy shall include a cross- liability clause.
<PAGE>

        d.     To take out employers' liability insurance that covers the
               liability of the Management Company and the lessor vis-a-vis
               their employees in accordance with the Torts Ordinance (New
               Version) and/ or in accordance with any other law, on account of
               death and/ or on account of any bodily injury (including
               emotional or mental injury) for every employee as a result of an
               accident or illness during and on account of his or her
               employment.

        e.     To take out insurance against loss of Rent and/ or loss of
               management fees and/ or consequential loss of profits to the
               lessor and/ or to the Management Company as a result of a
               physical loss or damage to the project and/ or to the Leased
               Premises, and any other insurance that the Management Company
               deems essential and is related to physical loss and/ or damage
               and/ or financial loss and/ or liability related to the project,
               its management, and its operation.

        f.     To handle payments for water, electricity, and energy for the
               public areas, payment of municipal and central government Taxes
               that apply to the public areas, payment of all other sums of any
               type or kind whatsoever that do not apply to specific areas, and
               payment of all other sums on account of services and Building
               maintenance and on account of the operations of the Management
               Company, as stated in this agreement.

4.      WORK TO BE CARRIED OUT BY THE MANAGEMENT COMPANY

        The Management Company is entitled to enter the Leased Premises at any
        time, with advance coordination with the lessee (except in urgent
        cases), and to carry out there any action that it believes to be
        necessary in order to exercise its rights under the present agreement.
        Without derogating from the generality of the aforesaid, the Management
        Company shall be entitled, inter alia, to open walls, floors, ceilings,
        and other parts of the Leased Premises and to replace and repair pipes
        and plumbing and make connections to them and to carry out any
        electrical work whatsoever.

        The Management Company undertakes to act to the best of its ability to
        minimize any disturbance to the lessee and to restore the status quo
        ante as soon as possible.

        The lessee undertakes to do whatever may be required to assist the
        Management Company in carrying out the work on the Leased Premises and
        to permit the Management Company to minimize any disturbance to the
        operation of the Leased Premises.

5.      MANAGEMENT AND MAINTENANCE FEES

        In consideration of the management and maintenance services that the
        Management Company will provide as stated in the management agreement,
        the lessee undertakes to pay the Management Company management and
        maintenance fees as follows:

<PAGE>

        a.     The lessee's proportional share (as stated in the Tenancy
               Agreement) of the costs associated with the operation,
               management, and maintenance of the Building by the Management
               Company and the fulfillment of the Management Company's
               obligations as enumerated in the Management Agreement (including
               financing costs and expenses on account of depreciation of
               equipment at the rate fixed by law, which shall be paid to the
               lessor for the installation and/ or replacement of equipment to
               serve the public and/ or the tenants of the Building or some of
               them) (hereinafter "Operating and Maintenance Expenses").

        b.     Payment of all expenses or of the lessee's proportional share in
               the expenses that, at the sole discretion of the Management
               Company, should be borne by the lessee and/ or by the lessee
               together with other specific lessees because the expense stems
               from the conduct of the specific business of the lessee and/ or
               the businesses of a number of lessees.

        c.     Expenses that may be caused by specific lessees shall be borne by
               those lessees (such as electricity for air conditioning).

        d.     In addition to payments on account of operating and maintenance
               expenses and expenditures as stated above, the lessee shall pay
               the Management Company a management fee equal to 15% (fifteen
               percent) of the total payment charged the lessee as stated above
               (that is, the actual payment will be cost plus 15%), plus value
               added tax according to law on the total sum of the payment.

        e.     The lessee may examine the management expenditures ledgers at any
               reasonable time with prior coordination with the manager of the
               Management Company and in the company offices.

6.      TERM OF THE MANAGEMENT AGREEMENT

        At the end of the Term of the Lease or the term of an option, should
        such apply, whichever is later, or upon cancellation of the Tenancy
        Agreement pursuant to the stipulations of the Tenancy Agreement, the
        present agreement shall lapse and a final reckoning shall be drawn up
        between the lessee and the Management Company concerning their credit
        and debit balances, pursuant to the terms of the Management Agreement,
        all of this subject to compliance with all conditions in the Tenancy
        Agreement for carrying out the reckoning.

7.      USE OF THE UPPER ROOF AND/ OR BALCONIES

        It is hereby agreed that the lessee shall have no right to use the upper
        roof above the Leased Premises or any other external roof without
        explicit written consent from the lessor.

8.      PARKING FACILITY

        It is hereby agreed that the parking facility will be managed by the
        lessor or by someone acting on its behalf, and the lessee undertakes to
        comply with their instructions.

<PAGE>

APPENDIX E

                                                                  Dec. 21, 2000

Kir Hed, Ltd.
RMPA House
Har Hotzvim
Jerusalem

Dear Sir or Madam:
                       Re: FINISHING WORK IN BEIT HADARIM

Pursuant to the Tenancy Agreement (hereinafter "THE TENANCY AGREEMENT") signed
on Dec. 21, 2000, between us and RMPA Properties, Ltd. (hereinafter "THE
LESSOR") concerning space in Beit Hadarim in Har Hotzvim in Jerusalem
(hereinafter "THE LEASED PREMISES");

And whereas it has been agreed between us and the Lessor that we will carry out
the Finishing Work in the Leased Premises (hereinafter "THE FINISHING WORK") by
means of a contractor to be selected by us for this purpose who has experience
in carrying out similar work in the Har Hotzvim industrial zone, the Malha
Technological Park, or some other high- tech park in Tel Aviv, and that you will
be given the right of first refusal to carry out the Finishing Work;

Accordingly we make the following commitment to you:

        1.     We shall provide you with a copy of the detailed plans and
               specifications for the Finishing Work, including all the working
               blueprints and specifications and any other and/ or additional
               plans as soon as they are ready.

        2.     As soon as we have received contractors' bids on the Finishing
               Work, we shall transmit all the proposals received to you and
               notify you as to which is our preferred proposal.

        3.     You shall be entitled to inform us, within seven days of
               receiving our notification and the contractors' proposals as
               stated in section 5 of the Tenancy Agreement, that you are
               interested in carrying out the Finishing Work yourselves, at the
               price and under the terms offered to us by the contractor whose
               proposal we preferred, as stated above.

        4.     Should you notify us that you are interested in carrying out the
               Finishing Work under the aforesaid conditions, we undertake to
               entrust the Finishing Work to you.

Sincerely yours,
Keryx Israel, Ltd.

CC: RMPA Properties, Ltd.

<PAGE>

                                   Appendix B
                                 BANK GUARANTEE
 To:
 RMPA PROPERTIES LTD.                                        DATE: __________
 --------------------

 Dear Sir:

                           Re: Bank guarantee no. ____________________________

 Pursuant to a request by Keryx Israel, Ltd. (hereinafter "the Guaranteed") we
 hereby guarantee the payment to you of any amount up to the amount of NIS
 __________ (_____________ New Israeli Sheqels), index- linked, in accordance
 with the indexation conditions enumerated below (hereinafter "the Amount of the
 Guarantee") that are or may be due you from the guaranteed.

For the purposes of the present guarantee

The "Base Index" means--

The index published on _____________ (date) for _________________ (month and
year), namely, ______________ points.

The "New Index" means--

The last index published before the actual payment of any amount pursuant to the
present guarantee.

If, on the date when we pay you any sum whatsoever in accordance with the
present guarantee, it transpires that the New Index has risen with respect to
the Base Index, we shall pay you that amount multiplied by the ratio of the New
Index to the Base Index.

We shall pay you from time to time, and in any case within ten days of receipt
of your initial written demand, any amount within the limit of the guarantee,
without your having to justify your demand or make a previous demand for payment
by the debtor, on condition that the entire sum we must pay in response to all
your demands taken together does not exceed the amount of the guarantee.

This guarantee will remain in force until _________________ (date), inclusive,
and any demand pursuant to it must be sent in writing to the branch indicated
below no later than the aforesaid date.

 This guarantee is irrevocable.

         Sincerely yours,

                                                             ---------------
                                                                      Bank
RMPA Properties Ltd. [rubber stamp, signature]

<PAGE>

To
RMPA PROPERTIES, LTD.  (hereinafter "the company")
P.O.B. 45079, RMPA House, Har Hotzvim
Jerusalem
Dear Sir,

Re: Confirmation of Insurance Coverage in Force from _______________
through ______________

We hereby confirm that we have issued the insurance policies enumerated below on
the content of the Leased Premises leased by the lessee whose name is stated
below, located in your Building in Har Hotzvim (Beit Hadarim), Jerusalem, and
for the lessee's business and activities in the Building.
1. EXPANDED FIRE INSURANCE
          Insured party _________________________ (hereinafter "the lessee")
          Property covered: The contents of the Leased Premises, and without
          derogating from the generality of the aforesaid, including any
          modifications, improvements, and additions to the Leased Premises,
          performed by and/ or on behalf of the lessee, as well as furnishings,
          equipment, and inventory of every sort.
          Amount of coverage: ________________
          Risks covered: The standard risks covered by expanded fire insurance,
          and without derogating from the generality of the aforesaid, including
          fire, explosion, earthquake, riots, strikes and malicious damage,
          flooding, water damage, and burglary Special stipulation: The policy
          includes a clause waiving subrogation vis-a-vis the company and/ or
          vis-a-vis all the other lessees and/ or tenants in the building,
          including all those who come on behalf of those enumerated above.
2. THIRD-PARTY LIABILITY INSURANCE
          Insured party _________________________ (hereinafter "the lessee")
          Limits of liability: ____________ per incident; ____________ total
          Nullification of limits: fire, explosion, panic, motor vehicle
          lifting, loading, and unloading equipment, poisoning and foreign
          substances in any food or beverage, and National Insurance
<PAGE>

         Special stipulations:
         (1) The policy includes a cross-liability clause among the units of the
         insured party.
         (2) The policy is expanded to indemnify the company on account of their
         liability as owners and managers of the leased premises and on account
         of their vicarious liability for acts of commission and/ or omission on
         the part of the lessee.
3. EMPLOYER'S LIABILITY INSURANCE
         Insured party _________________________ (hereinafter "the lessee")
         Special stipulation: The policy is expanded to indemnify the company on
         account of its liability as owners and managers of the Leased Premises
         and on account of its vicarious liability for acts of commission and/
         or omission on the part of the lessee.

The aforesaid policies may not be cancelled without prior notification sent
         to the company by registered mail 60 days in advance.
         Sincerely yours,
         The Insurer

         ----------------

RMPA Properties Ltd. [rubber stamp, signature]
Keryx (Israel) Ltd. [rubber stamp, signature]<PAGE>

                                                                 EXHIBIT 10.28
                                    AMENDMENT

This amendment (the "Amendment"), dated March 29, 2001, is being made between
KERYX BIOPHARMACEUTICALS, INC., a corporation organized under the laws of the
State of Delaware, with offices at Kiryat Mada 5, Jerusalem 91236 Israel
("Keryx"), and CHILDREN'S MEDICAL CENTER CORPORATION, 300 Longwood Avenue,
Boston, Massachusetts 02155 United States of America ("CMCC").

WHEREAS the parties executed a License Agreement, dated November 12, 1999,
pursuant to which, among other things, meet certain development milestones (the
"License Agreement"); and

WHEREAS the parties have determined that the proper development and funding of
the technology that is the subject of the License Agreement justifies amendments
to the clauses addressing the development milestones and Keryx's reporting
requirements;

IT IS HEREBY AGREED by and between the parties:

    1. Article III.B.1 of the License Agreement shall be deleted in its entirety
       and replaced with the following language:

       B. Licensee shall accomplish development of Licensed Products and/or
Licensed Processes according to the following timetable:

            1. file an Initial New Drug Application ("IND") for a Licensed
               Product with United States Food and Drug Administration ("FDA")
               or its foreign equivalent in a country with reasonably comparable
               requirements within forty two (42) months from the identification
               of the first lead compound; and

    2. This Amendment shall not be deemed to alter in any manner any rights
       and/or obligations of either party except as specifically set forth
       above.

IN WITNESS WHEREOF, the parties hereto have executed this Amendment, by proper
persons duly authorized.

KERYX BIOPHARMACEUTICALS, INC.            CHILDRENS MEDICAL CENTER
                                          CORPORATION

By: /s/ Morris Laster                     By: /s/ Willliam New
   -----------------------------             -------------------------

Name: Morris Laster, M.D.                 Name: William New

Title: Chief Executive Officer            Title:

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