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                                                                   EXHIBIT 10.19


                               TENANCY AGREEMENT

                                                   [ref. heh het - shin kaf B-6]

              Drafted and signed in Jerusalem on 13 December 1999

Between:      HAR HOTZVIM PROPERTIES LTD. (51-168405-2)
              27 Hamered St., Tel Aviv
              (hereinafter "the lessor")

And:          BRT BIOPHARMACEUTICALS LTD. (51-285095-9)
              216 Jaffa Road, 94383 Jerusalem
              (hereinafter "THE LESSEE")

Whereas       The lessor is the owner of rights in land known as parcel 110 in
              block 30241, on Qiryat Hamada Street, Har Hotzvim, Jerusalem;

And whereas   An existing building is located on this land and other buildings
              are in the process of planning or construction and development;

And whereas   The lessee is interested in leasing from the lessor a unit located
              in Building B on the land, all as stipulated in this agreement;

And whereas   The lessor agrees to lease to the lessee a unit in Building B on
              the property, as stipulated in this Agreement;

And whereas   The parties have agreed on the principles for adapting the leased
              property to the requirements of the lessee and have agreed on all
              other conditions of the transaction;

NOW THEREFORE BE IT AGREED, STIPULATED, AND DECLARED AS FOLLOWS:

1.       INTRODUCTION

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

         1.2      DEFINITIONS

                  In this agreement, the following terms shall be interpreted as
indicated:

                  1.2.1    "THE PROPERTY" - Parcel 110 in block 3241, on Qiryat
                           Hamada Street, Har Hotzvim, Jerusalem, including
                           everything built thereon and everything that may be
                           built and developed thereon. The boundaries of the
                           property are indicated on the sketch attached to this
                           agreement as an integral part thereof, and marked
                           "Appendix A-1."
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                  1.2.2    "THE PROJECT" - The Ramot Meir project, under
                           construction on the property, which includes and will
                           include multipurpose structures, car parks, and open
                           areas.

                           The Project is intended to comprise three main
                           buildings and a tower (Building A, Building B,
                           Building C, and Building D). The term "project"
                           includes of these buildings and all other structures,
                           facilities, areas, lawns, paths, and everything
                           located on the property.

                           The project will be erected in stages at the
                           discretion of the lessor.

                  1.2.3    "BUILDING A" - An exiting structure in the Project
                           whose boundaries are marked in the sketch in Appendix
                           A-1, which consists of several stories.

                           "BUILDING B" - A building currently being planned and
                           erected, whose boundaries are marked in the sketch in
                           Appendix A-1, and which will include a multistory
                           parking garage and multipurpose floors.

                           "BUILDING C" - A building currently being planned,
                           whose boundaries are marked in the sketch in Appendix
                           A-1, and which will include a multistory parking
                           garage and multipurpose floors.

                           "BUILDING D" - a building currently being planned,
                           intended as a tower to be erected, if approval is
                           forthcoming, above a portion of Building C.

                  1.2.4    "THE LEASED PREMISES" - An area on the third-floor
                           (level 722) of Building B. The boundaries of the
                           leased premises are marked in blue on the sketch
                           attached to this agreement as an integral part
                           thereof and designated APPENDIX A-2. For the purposes
                           of this agreement the leased premises are considered
                           to cover 400 square meters gross. The leased premises
                           are designated as Unit B/3/101 in the Project. It is
                           stipulated that the leased premises include an area
                           of approximately 283 square meters intended for the
                           offices of the lessee, marked on the sketch with the
                           word "offices," and an area of approximately 117
                           square meters intended for the laboratories of the
                           lessee, marked on the sketch with a work
                           "laboratories." The border between the office area
                           and the laboratory area is marked in red on the
                           sketch in APPENDIX A-2. For the purposes of this
                           agreement the total area of the leased premises is
                           approximately 400 square meters gross, as stated
                           above. It is stipulated that the office area will
                           include all the work, systems, and utility supplies
                           in accordance with Appendix B to this agreement
                           (Technical Specification) that are included in the
                           term "the leased premises," whereas the laboratory
                           area will be handed over to the lessee by the lessor
                           as a shell only and all interior, finishing, and
                           infrastructure work for the laboratory area for the
                           needs of the lessee will be done by the latter, at
                           the sole expense and responsibility of the lessee.

                   1.2.5   "MONTH" - A month according to the Gregorian
                           calendar, beginning on the first day of that month
                           and concluding on the least day of that month, in
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                           accordance with the number of days in that month in
                           that year according to the Gregorian calendar.

                  1.2.6    "MANAGEMENT COMPANY" - A firm designated by the
                           lessor to provide management and maintenance services
                           for the project, whether this company is that of the
                           lessor or any other company selected by the lessor.

         1.3      The appendices to this agreement are an integral part thereof.
                  The appendices are as follows:

         Appendix A-1:     Sketch of the property

         Appendix A-2:     Sketch of the leased premises

         Appendix B:       Technical specification and work to be performed by
                           the lessor in the offices of the lessee

         Appendix C:       Interior work in the laboratory area of the leased
                           premises to be implemented by the lessee (to be
                           added at a later date)

         Appendix D:       Sample promissory note

         Appendix E:       Insurance appendix (with two subsidiary appendices)

         Appendix F:       Sample bank guarantee

         1.4      The headings of the sections and provisions of this agreement
                  and its appendices have been inserted to facilitate the
                  reading of the agreement and its appendices. They are not part
                  of the agreement and the agreement shall not be interpreted
                  according to them.

2.       UNDERTAKING TO LEASE

         The lessee hereby undertakes to lease the leased premises from the
         lessor and the lessor hereby undertakes to lease the leased premises to
         the lessee, all in accordance with all conditions and provisions of
         this agreement.

         In addition, the lessee hereby undertakes to conclude a management
         contract with the management company designated in this agreement and
         to comply with all provisions and conditions of the management contract
         as part of this obligations vis-a-vis the lessor according to this
         agreement.

3.       TERM OF THE LEASE

         3.1      The term of the tenancy of the leased premises is hereby set
                  at 8 years, beginning on 1 March 2000 (hereinafter "the
                  starting day of the lease") and concluding on 29 February 2008
                  (this period shall be designated in this agreement "the term
                  of the lease").
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                  The lessee reserves the right to shorten the term of the lease
                  in accordance with and subject to the provisions and
                  conditions of section 24 below.

         3.2      It is hereby agreed and stipulated that the starting day of
                  the lease may be postponed by the lessor, and this in the case
                  stipulated in section 23 below, as well as in the case that
                  the lessor finds that the work on the project and/or the
                  building in which the leased premises are located do not
                  permit the start of tenancy.

                  Should the lessor give notice of a postponement of the
                  starting day of the lease, then the term of the lease shall
                  begin on the new date stated by the lessor and shall last for
                  8 years, starting on the new date set by the lessor as the
                  "starting day of the lease." In such case, all dates
                  stipulated in this agreement shall be modified
                  correspondingly.

4.       CONVEYANCE OF THE LEASED PREMISES

         4.1      The lessee undertakes to take possession of the leased
                  premises on the starting day of the lease.

         4.2      Until the date of the handover of possession of the leased
                  premises to the lessee, the lessor shall complete the work in
                  the office area of the leased premises, all in accordance with
                  the Technical Specification attached to this agreement as an
                  integral part thereof, and designated APPENDIX B.

                  By way of sound practice, it is hereby clarified that both the
                  lessor and other lessees in the building and the project are
                  entitled, even after the conveyance of possession of the
                  leased premises to the lessee, to continue to carry out
                  construction and finishing work in the project (and in every
                  part thereof), in the building in which the leased premises
                  are located as well as in other leased areas of this building.

                  The lessor shall make every effort to ensure that work as
                  stated in the preceding paragraph will be conducted with
                  minimal disturbance to the lessee.

         4.3      The lessee confirms that it has seen and carefully examined
                  the plans for the leased premises and the technical
                  specification and that subject to their implementation the
                  leased premises are fully satisfactory to it.

         4.4      In everything that has to do with the interior work in the
                  laboratory area of the leased premises that will be performed
                  by the lessee, there shall apply the provisions of section 14
                  below and the provisions of the document concerning "interior
                  work by the lessee," attached to this agreement as part
                  thereof and designated APPENDIX C.

         4.5      The lessor undertakes to perform the interior work in the
                  office area of the leased premises, enumerated in the
                  technical specifications (Appendix B to the agreement) within
                  80 days after the lessee conveys to the lessor the lessee"
                  final plans for the internal division of the leased premises.
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                  The lessee undertakes to convey to the lessor, by20 December
                  1999, the lessee's plans in their final form and adapted to
                  the internal division of the office area in the leased
                  premises. Should the delivery of the lessee's plans to the
                  lessor be delayed until after the aforesaid date the transfer
                  of the leased premises will be postponed correspondingly and
                  similarly all the dated enumerated in this agreement will be
                  delayed correspondingly, but in any case the starting date of
                  the lease shall not fall after 1 April 2000.

         4.6      Should the lessor delay the date of the transfer of possession
                  of the leased premises beyond the lapse of 80 days from the
                  date of delivery of the lessee's plans, in their final and
                  appropriate form, the lessor shall pay the lessee as agreed
                  and prepossessed damages a sum equal to the monthly rental for
                  the period during which the conveyance of possession of the
                  leased premises was delayed, prorated, and shall also
                  reimburse the lessee for the rent paid to it at the time of
                  the signing of this agreement for that same period, pro rata.

5.       RENT

         5.1      The monthly rent for each month during the term of the lease
                  between 1 March 2000 and 29 February 2004 is hereby set at the
                  amount of NIS 20,778 (twenty-thousand seven hundred
                  seventy-eight New Israeli Sheqels), plus indexation
                  differentials (hereinafter "the monthly rent").

                  The amount of the monthly rent for each month of the term of
                  the lease from 1 March 2004 until 29 February 2008 is hereby
                  set at the amount of NIS 22,855 (twenty-two thousand eight
                  hundred fifty-five New Israel Sheqels), plus indexation
                  differentials (hereinafter "the monthly rent").

         5.2      In addition to the monthly rent the lessee shall add and pay
                  to the lessor Value Added Tax at the legal rate at the time of
                  payment. The rent shall not be reduced below the amounts
                  stipulated in section 5.1 above.

         5.3      The monthly rent as stipulated above shall be linked to the
                  index and shall be paid with the addition of indexation
                  differentials, using the following indexation base:

                  5.3.1    It is agreed that the "determining index" according
                           to which the monthly rental payments will be
                           calculated is the index published on November 15,
                           1999 (106.8 points).

                  5.3.2    It is agreed that the "known index" is the last known
                           index on the day on which the monthly rent payment is
                           actually made.

                  5.3.3    "The index" means the index known as the "Consumer
                           Price Index" (including fruits and vegetables),
                           published by the Central Bureau of Statistics and
                           Economic Research. Should the publication of this
                           index be discontinued, it shall be replaced by
                           whatever index is stipulated by the Central Bureau of
                           Statistics as the index that replaces it; if none is
                           so designated, it shall be replaced by the index
                           accepted by the Bank of Israel as the index that
                           replaces
<PAGE>

                           it, whether or not said indices are based on the same
                           data as the aforementioned index.

6.       PAYMENT OF RENT

         6.1      The lessee undertakes to pay the lessor monthly rent as
                  follows:

                  6.1.1    Monthly rental payments for the entire term of the
                           lease, plus Value Added Tax, shall be paid by the
                           lessee to the lessor in quarterly payments (each in
                           the amount of the monthly rent for three months, plus
                           indexation differentials plus Value Added Tax), paid
                           for every three-month period in advance, no later
                           than the first day of the first month in each
                           quarter.

                           The rental payments in accordance with this
                           subsection shall be paid in every year that the lease
                           is in effect on the first day of each of the
                           following months: April, July, October, January.

                  6.1.2    It is agreed that, notwithstanding the provisions of
                           section 5.1 and section 6.1.1 above, the lessee shall
                           pay the lessor by check, on the day of the signing of
                           this agreement, the sum of NIS 139,253 (one hundred
                           thirty-nine thousand two hundred fifty-three New
                           Israel Sheqels), plus Value Added Tax, on account of
                           the monthly rent and on account of the monthly
                           parking fees for four parking spaces as stated in
                           section 26 below, for the period running from1 March
                           2000 through 30 September 2000.

                           It is agreed that all other monthly rental payments,
                           starting with the period that begins on 1 October
                           2000, shall be paid in the amounts and on the dates
                           stipulated in section 6.1.1 above. The last rental
                           payment shall relate to the period between the first
                           day of the month of January of the last year of the
                           lease and the 29th day of the month of February of
                           the last year of the lease.


                  6.1.3    The monthly rental payments shall be made with in
                           addition of indexation linkage differentials computed
                           according to the ratio between the base index and the
                           known index.

                  6.1.4    The lessee shall not be entitled to prepay the
                           monthly rent except with the prior written consent of
                           the lessor, if given.

         6.2      At the time of the signing of this agreement the lessee
                  delivers to the lessor 14 index-linked promissory notes
                  phrased as stipulated in APPENDIX D to this agreement. The
                  amounts of the promissory notes and their dates of maturity
                  shall correspond to the sums and dates stipulated in sections
                  5.1 and 6.1.1 above (for the period beginning on 1 March 2000
                  and concluding on 29 February 2004). Except for the first
                  payment, which relates to the period from 1 March 2000 through
                  30 September 2000, which is paid by check as stated, and
                  except for the last promissory note, which relates to the
                  period from 1 January of the last year of the lease through 29
                  February of the last year of the lease, as stated, the amount
                  of each promissory note shall be the sum of the monthly rent
                  and the monthly parking fees for four parking spaces, as
                  stated, for three months, plus Value Added Tax (base index:
                  106.8 points).

                  The lessee undertakes to present to the lessor, on the dates
                  stipulated in section 24 below, 16 indexed promissory notes
                  phrased as stipulated in APPENDIX D to this
<PAGE>

                  agreement. The amounts of the promissory notes and their dates
                  of maturity shall correspond to the sums and dates stipulated
                  in sections 5.1 and 6.1.1 above (for the period beginning on 1
                  March 2004 and concluding on 29 February 2008). The amount of
                  each promissory note shall be the sum of the monthly rent for
                  three months, plus Value Added Tax (base index: 106.8 points).

         6.3      The aforementioned promissory notes will be payable to the
                  order of the lessor, with the right of endorsement to the
                  lessor's bank for collection only. The promissory notes shall
                  be signed by the lessee.

                  The aforesaid promissory notes shall be given to guarantee
                  payment of the rent and to facilitate collection thereof.

                  Only the actual and timely redemption of each promissory note
                  shall be considered to constitute appropriate payment of the
                  rent covered by that note.

         6.4      The lessee hereby conveys to the lessor a certified copy of an
                  irrevocable order given to Bank Leumi Le-Israel, Ltd., Mahane
                  Yehuda Branch (No. 913) to pay the aforesaid promissory notes
                  from the lessee's account with this bank (account number
                  121600/19) and undertakes to cause the promissory notes to be
                  honored by this bank in timely and complete fashion.

         6.5      Each of the above subsidiary provisions of the present section
                  6 constitutes a principal condition of this agreement, the
                  violation of which constitutes a fundamental breach of the
                  agreement to which are applicable also the provisions of
                  section 18 below.

         6.6      By way of sound practice it is hereby stated that each of the
                  promissory notes in accordance with section 6.2 above is
                  deemed to be a note with a face value in the amount written
                  (in words and in digits) on the note, plus an amount whose
                  rate is the same as the rate of the Value Added Tax stipulated
                  by law on the date set for payment of the note. The amount of
                  Value Added Tax shall be computed also with regard to
                  indexation differentials. The lessee undertakes to pay the
                  amount of the note (plus indexation differentials), including
                  Value Added Tax as stated, on the date set for payment.
                  Computation of the Value Added Tax shall be based on the rate
                  of Value Added Tax that applies to rental transactions (should
                  there be a distinction among different types of transactions).
                  The lessee undertakes not to claim that the note is
                  conditional or not for the face amount.

7.       OBJECTIVE OF THE TENANCY

         7.1      The lessee is leasing the leased premises and every part
                  thereof for the purpose of offices and laboratories for
                  research and development in the field of medicine and
                  para-medicine only, and undertakes to conduct on the leased
                  premises a use for this objective throughout the term of the
                  lease.

         7.2      The lessee alone and at its expense is responsible for
                  obtaining business permits for the use of the leased premises.
<PAGE>

         7.3      The lessee affirms that it is considering submitting a request
                  to receive the status of "approved enterprise" and/or to
                  conduct "an approved project" (in the sense of these terms in
                  the Encouragement of Capital Investment Laws), and this within
                  18 months of the starting date of the lease in accordance with
                  this agreement. The lessee affirms that to the best of its
                  knowledge it meets the criteria stipulated and required to
                  receive the status of approved enterprise and/or to conduct an
                  approved project as stated.

         7.4      The provision of section 7.1 is a principal condition of this
                  agreement, the violation of which constitutes a fundamental
                  breach of the agreement to which are applicable also the
                  provisions of section 18 below.

8.       IDENTITY OF THE USERS OF THE LEASED PREMISES

         8.1      The leased premises are leased to the lessee alone; the lessee
                  may not transfer the leased premises or any part thereof to
                  another party, nor may the lessee grant any right whatsoever
                  in the leased premises or in any part thereof to other parties
                  without the prior written consent of the lessor, when the
                  alternative lessee is to the full satisfaction of the lessor.

                  Notwithstanding what is stated above, the lessor may reject a
                  subtenant or substitute lessee for reasonable cause only. It
                  is made clear that the purpose of the tenancy of the
                  substitute lessee shall not be limited to the objective of the
                  lease in accordance with section 7.1 above. It is made clear
                  that the rejection of a proposed substitute lessee by the
                  lessor because of the objective of the tenancy of the proposed
                  substitute lessee is inappropriate to the nature of the entire
                  project is reasonable. If the lessor has approved a subtenant
                  as stated, the lessee shall continue to bear responsibility
                  for all its undertakings in accordance with this agreement.

         8.2      Given that the lessee is a limited liability corporation, it
                  is agreed that any change in the control of the company shall
                  be considered to be a transfer of rights that is not allowed
                  under section 8.1 of above (and accordingly requires the
                  consent of the lessor in the conditions stated above); the
                  lessor shall not reject a request by the lessee other than for
                  reasonable cause. Should the lessor reject a request by the
                  lessee for other than reasonable cause, the lessee shall be
                  entitled to shorten the term of the lease in accordance with
                  the provisions and conditions of this agreement, subject to
                  finding a substitute lessee to the full and exclusive
                  satisfaction of the lessor. The lessee declares that the
                  stockholders as of the date of the signing of this agreement
                  are Lakaro Biopharmaceuticals Inc. (99%) and Morris Last (1%),
                  and that the lessee company is controlled by these alone.

         8.3      Each of the provisions of section 8 is a principal condition
                  of this agreement, the violation of which constitutes a
                  fundamental breach of the agreement to which are applicable
                  also the provisions of section 18 below.
<PAGE>

9.       TAXES AND OTHER COMPULSORY PAYMENTS ON ACCOUNT OF THE LEASED PREMISES

         The parties agree that all taxes, levies, fees, and other compulsory
         payments that may be imposed with relation to the leased premises and
         any part thereof and that are incumbent upon the party in possession of
         the property shall all and with no exception devolve on the lessee.
         Without detracting from the generality of the aforesaid and from other
         sections of this agreement, it is hereby made plain that the lessee
         shall pay the municipal rates due on account of the leased premises.

         Property tax and other taxes imposed exclusively upon the owner of the
         property and on the owner alone, including sewage, road construction,
         drainage, and similar levies or fees, shall be paid by the lessor.

10.      EXPENDITURES FOR USE AND MAINTENANCE OF THE LEASED PREMISES AND
         RESPONSIBILITY FOR DAMAGES

         10.1     The expenditures and payments required for use of the leased
                  premises and as a result of the use of the leased premises, of
                  any type whatsoever, including electricity, water, telephone,
                  telecommunications, heating, air-conditioning, and gas, shall
                  devolve exclusively on the lessee.

         10.2     Should no water meter be installed in the leased premises, in
                  accordance with a decision of the lessor, payments for water
                  usage shall be made by the lessee to the lessor (plus Value
                  Added Tax) directly or through the management company. The
                  lessee's share of the outlay for water usage shall be computed
                  by the lessor according to the relative share of the leased
                  premises in the building in which the leased premises are
                  located. The payment for water shall be made within two weeks
                  of the day on which the lessor submits a bill for this to the
                  lessee.

                  Should the water usage of the building in which the leased
                  premise are located be marginal or negligible, the lessor
                  shall be entitled to determine that the total water usage of
                  the building will be included as part of the "actual
                  expenditures' of the management company on account of which
                  the lessee pays it "contributory share" in the "expenditures
                  of the company," as stipulated in the management agreement.

         10.3     The lessee alone is responsible for maintaining the leased
                  premises and its systems in working order and for repairing
                  any damage or malfunction that may be caused or that may arise
                  in the leased premises during the term of the lease. The
                  lessee shall not bear responsibility for repairing any damage
                  or malfunction that occurs beyond the outside walls of the
                  leased premises or in the structure of the concrete ceiling of
                  the leased premises or in the building systems outside the
                  leased premises that are not systems of the leased premises,
                  except for damage or malfunction that results from an act of
                  commission or omission on the part of the lessee. The lessee
                  shall bear responsibility for all damage to windows of the
                  leased premises. The lessor shall bear responsibility for
                  repairing any damage or malfunction that results from faulty
                  construction and/or the use of defective building materials,
                  unless these damages
<PAGE>

                  result from an act of commission or omission on the part of
                  the lessee, in which case the lessee shall bear responsibility
                  for these damages.

         10.4     The lessee alone and at its expense shall be responsible for
                  any damage that may be caused to the leased premises, to
                  property, and to any human being therein.

                  In addition to the aforesaid, it is agreed that the lessee
                  shall bear responsibility for damages of any type whatsoever
                  that may be caused to the lessor and/or to the management
                  company and/or to any third party whatsoever by a negligent
                  and malicious act of commission or omission on the part of the
                  lessee, including, and without detracting from the stated
                  generality, any damage to the body or property of any person
                  who may be found at any time whatsoever in the area of the
                  project. The lessee hereby releases the lessor and/or the
                  management company from any liability under law with relation
                  to any such damage and undertakes to compensate or indemnify
                  them in any amount of damage that may be caused to the lessor
                  and/or to the management company and on account any amount
                  that the lessor and/or the management company may be required
                  to pay in relation to any damage and outlay and/or loss and/or
                  fine that may be caused as stated. The compensation and
                  indemnification shall include any legal expenses that the
                  lessor and/or the management company may incur in connection
                  with the aforesaid and shall be paid to the lessor and/or to
                  the management company immediately upon the first request,
                  provided that the lessee has been given a reasonable
                  opportunity to defend itself against any claim that may be
                  submitted in this regard.

                  It is hereby stated and agreed that the lessee and all those
                  acting on its behalf explicitly waive any right of action
                  against the lessor and/or against the management company and
                  all those acting on their behalf as well as against other
                  tenants of the project whose tenancy and/or management
                  agreements include a parallel section concerning a waiver of
                  the right to lodge an action against the lessee on account of
                  damage for which it is entitled to indemnification under the
                  insurance policies that it undertook to take out in the
                  management contract, in the tenancy agreement, or in any
                  appendix that is a part thereof. The waiver of the right lodge
                  an action shall apply also to damage for which the tenant is
                  not entitled to indemnification because of a deductible clause
                  in the insurance policy. The waiver of the entitlement to
                  indemnification shall not apply vis-a-vis a party that has
                  caused damage with malicious intent.

11.      INSURANCE

         The lessee undertakes to carry insurance as specified in APPENDIX E to
         the agreement and undertakes to fulfill each of the obligations imposed
         on the lessee in APPENDIX E to the agreement.

         Each of the lessee's obligations under the present section 11 and
         Appendix E to the agreement (and its subsidiary appendices) is a
         principal condition of this agreement, the violation of which
         constitutes a fundamental breach of the agreement to which are
         applicable also the provisions of section 18 below.
<PAGE>

12.      NONAPPLICATION OF TENANT PROTECTION

         The lessee declares that it is aware of and agrees to the following:

         12.1     The lessee is not and shall not be a protected tenant under
                  the Tenant Protection Law (consolidated version) 5732-1972.

         12.2     The tenancy is an unprotected tenancy. Neither it nor the
                  parties to the agreement are subject to the aforesaid Tenant
                  Protection Law or to any other law or judgment that relates to
                  the protection of tenants or control of rent and that may
                  replace or supplement the aforesaid law.

         12.3     The lessee has not paid and it is agreed that it shall not
                  make any payment nor grant to the lessor any right whatsoever
                  that may be deemed to be key money. It is agreed that any
                  payment, consideration, right, or benefit that the lessor may
                  derive from the lease, the leased premises, and the lessee
                  shall also be deemed to be part of the rent in every respect,
                  and this in addition to the rent stipulated in this agreement.

         12.4     The lessee declares that it is aware that the leased premises
                  are part of a structure erected after 1 April 1954 (in
                  practice after 20 August 1968) and leased for the first time
                  after 31 March 1955 (and in practice after 20 August 1968) and
                  that the leased premises are free of any tenant on the date of
                  the signing of this agreement.

         12.5     The lessee declares that the leased premises are free of any
                  lessee and of any person with the rights to occupy it (except
                  for the lessor).

         12.6     At the time of the vacation of the leased premises by the
                  lessor, the lessor shall not be entitled to any payment of
                  right of any kind whatsoever from the lessor and/or from any
                  substitute tenant or from any other party, including on
                  account of improvements or repairs to the leased premises.

13.      PLANNING AND CONSTRUCTION OF THE PROJECT

         13.1     The lessee confirms that it is aware that the programming,
                  planning, infrastructure development, and construction work on
                  the project (each and all of the above, hereinafter "the
                  construction of the project") have not yet been completed,
                  except for the existing building (Building A), to which
                  modifications and additions will also be made. The
                  construction of the project (and every part thereof) includes,
                  in part, the erection of buildings, development and finishing
                  work, as well as interior work in some of the completed
                  structures. The work will be performed in stages and in
                  accordance with schedules, with no time limit and on the basis
                  of existing plans or plans that may be drafted in the future
                  or plans that may be modified in the future, all at the
                  discretion of the lessor.

         13.2     It is agreed that the lessee shall submit no claims or actions
                  against the lessor and against any third party whatsoever on
                  account of any disturbance or damage that may be caused to it,
                  if such is caused, on account of construction of the project
                  (and any portion thereof) or on account of the completion
                  thereof. It is further agreed that the
<PAGE>

                  lessee shall not take any action or institute any proceeding
                  that may constitute any infringement whatsoever of the
                  lessor's freedom to plan the project or hinder construction
                  works on the project by or on behalf of the lessor, or any
                  part thereof.

14.      INTERIOR WORK IN THE LEASED PREMISES BY THE LESSEE

         14.1     It is agreed that the lessee will obtain possession of the
                  leased premises in the engineering condition as is and in
                  which or in relation to which are included all of the
                  installations and components enumerated in Appendix B to the
                  agreement (Technical Specifications).

         14.2     It is agreed that except for what is incumbent upon lessor in
                  accordance with Appendix B to the agreement with regard to the
                  office area of the leased premises and this area alone, all
                  work to adapt the leased premises, including the laboratory
                  area in the leased premises, to the purpose of the tenancy and
                  the use of the lessee, including any construction, insulation,
                  and assembly whatsoever in the leased premises, including
                  various systems and utility supplies (each of these
                  hereinafter "interior work"), shall be performed by the lessee
                  alone, at its responsibility and expense.

                  No work or utility supply in the leased premises or to the
                  leased premises, except for those enumerated in Appendix B to
                  the agreement (Technical Specifications) is or shall be
                  incumbent upon the lessor.

         14.3     It is hereby agreed that the lessee may not perform any
                  interior work on the leased premises except in accordance with
                  and subject to the provisions of Appendix C to the agreement,
                  which is an integral part thereof. It is the responsibility of
                  the lessee to receive any permit or license required bylaw for
                  the performance of interior work.

                  The lessee shall begin the interior work in the laboratory
                  area of the leased premises no later than 1 March 2002, on
                  condition that the lessee's plans (including plans for
                  systems) have been approved in advance and in writing by the
                  lessor. The lessee undertakes to complete the interior work in
                  the laboratory area of the leased premises within three months
                  of the start of the aforesaid work.

                  The lessor shall not refrain from approving the lessee's plans
                  for interior work in the laboratory area of the leased
                  premises other than on engineering grounds and/or reasonable
                  cause.

         14.4     After the completion of the interior work in the laboratory
                  area of the leased premises by the lessee, the lessee shall be
                  forbidden to make any modification to the entire leased
                  premises and its systems; nor shall it be allowed to make any
                  addition to the leased premises (including any fixed
                  installation or system) except with the prior written consent
                  of the lessor, which will be weighed by the lessor at its
                  exclusive discretion.

         14.5     In order to avoid any misunderstandings it is hereby stated
                  that if water is supplied to the leased premises directly from
                  the local authority, the lessee shall sign a contract
<PAGE>

            with the Jerusalem municipality for the supply of water to the
            leased premises by 1 March 2000 and see to it that a water meter is
            installed for the leased premises by this date, at its own expense.
            It is further agreed that the lessee shall sign a contract with the
            Electric Company for the supply of electricity by the starting day
            of the lease and see to it that an electric meter is installed for
            the leased premises by this date, at its own expense.

      14.6  In no case whatsoever may the lessee carry out any work or
            installation or use or modification that may require a quantity of
            electricity or air-conditioning that exceeds the quantities and
            scope stated in Appendix B (Technical Specifications).

      14.7  Each of the provisions of the present section 14 is a principal
            condition of this agreement, the violation of which constitutes a
            fundamental breach of the agreement to which are applicable also the
            provisions of section 18 below.

15.   RETURN OF THE LEASED PREMISES TO THE LESSOR

      15.1  At the conclusion of the term of the lease and at any date prior to
            then, should be tenancy end or expire before the end of the term,
            the lessee shall be obligated to return the leased premises to the
            lessor free of every human being and object, with the leased
            premises in the condition stipulated in section 15.2 below.

      15.2  The lessee undertakes to return the leased premises to the lessor
            with the leased premises in a sound and fit condition as received,
            except for reasonable wear, in addition to all the interior work,
            including all improvements, renovations, work, additions,
            modifications, and systems that may be carried out or erected in the
            leased premises, whether by the lessor or by the lessee.

            If the lessor does not ask the lessee to remove all work, additions,
            installations, or systems whatsoever (including in accordance with
            Appendix C to the agreement), all of these shall belong to the
            lessor, and the lessee shall not be entitled to any payment,
            indemnification, or consideration for them from the lessor.

      15.3  Shortly before the end of the lease the lessor shall draw up a list
            of the work, defects, and repairs (each of these, hereinafter "the
            repairs") that the lessee shall carry out before returning the
            leased premises to the lessor.

      15.4  The list according to section 15.3 shall also include the prices of
            the cost of the repairs; in the event that the lessee does not carry
            out the repairs by the end of the term of the lease lessor shall be
            entitled to perform them in its stead and the lessee shall be
            obligated to pay the lessor by the end of the lease the value of the
            cost of the repairs even if they have not yet been carried out or
            will not be carried out by the lessor. Nothing stated here is
            intended to detract from the right of the lessor vis-a-vis the
            lessee to receive compensation or any remedy on account of the
            nonperformance of the repairs in timely fashion by the lessee in
            accordance with provisions of this agreement (including compensation
            for a delay in leasing the premises to other parties).
<PAGE>

            Should the lessee disagree as to the need to carry out repairs
            and/or about the prices set with regard to the cost of the repairs,
            the disagreement shall be resolved, no later than two weeks before
            the end of the term of the lease, by an engineer agreed upon by the
            two parties. Should the parties fail to reach agreement concerning
            the identity of the engineer, then the identity of this engineer
            shall be determined by the secretary (or chair) of the Jerusalem
            district of the AAAI association (after request of either party), on
            condition that his or her appointment and decision be rendered
            within two weeks from the day that the lessee announces its
            disagreement with the prices.

      15.5  No later than two weeks before the end of the term of the lease the
            lessee shall deliver to the lessor certification by the
            municipality, the electric company, and Bezeq that the lessee has
            made all payments incumbent upon it for the period until the end of
            the lease, including those for water, electricity, municipal rates,
            and telecommunications.

      15.6  Each of the provisions of the present section 15 is a principal
            condition of this agreement, the violation of which constitutes a
            fundamental breach of the agreement to which are applicable also the
            provisions of section 18 below.

16.   MAINTENANCE OF THE BUILDING AND OF SERVICES AND FACILITIES IN THE BUILDING
      THAT SERVE THE LEASED PREMISES AND THOSE VISITING THE LESSEE

      16.1  The lessor undertakes to install a management company whose function
            will be to manage and operate the project and also to maintain the
            project, its access routes (including paved surfaces, open space,
            and plazas that are within the area of the project) and the
            passageway and stairways within it, the project systems, and the
            outside portions of each building in the project.
      16.2  The lessor undertakes to install a management company whose function
            will be to operate the systems and facilities that service the
            project and to see to the cleanliness of the project.

      16.3  The services of the management company shall relate only to those
            portions of the project that have been completed.

      16.4  The lessor makes known that it has designated Park Meir Management
            Company, Ltd., as the management company; this shall be the
            management company as long as the lessor has not stipulated
            otherwise.

      16.5  The lessee undertakes to sign a contract with the management company
            at the time of the signing of this agreement. A breach of contract
            with the management company shall be deemed to be a breach of this
            agreement. In addition, the failure of the lessee to conclude the
            stated contract with the management company shall be considered to
            be a breach of a principal condition of this agreement.

      16.6  The management company shall take out various insurance policies as
            enumerated in the management contract. It shall also be entitled to
            add or subtract various policies.
<PAGE>

            However, nothing in the maintenance of these policies by the
            management company shall detract from the liability of the lessee or
            detract from the insurance obligations of the lessee.

      16.7  The lessee undertakes to make payments to the management company
            starting with the period that begins on 1 March 2000 and until the
            end of the term of the lease and the return of possession of the
            leased premises to the lessor in accordance with the provisions of
            this agreement.

      16.8  It is agreed that notwithstanding what is stated in the management
            contract, with regard to the period that begins on 1 March 2000 and
            concludes on 31 December 2000, the lessee's payments to the
            management company for its monthly contributory share shall be in
            the amount of NIS 12.70 for each square meter of the leased premises
            (that is, the sum of NIS 5080 for the entire leased premises), plus
            Value Added Tax, with this sum linked to the index (base index:
            106.8 points, published on 15 November 1999). These payments by the
            lessee to the management company shall be made every three months in
            advance, starting on 1 July 1999 and concluding on 31 December 2000.
            The first payment shall be made on 1 March 2000 for the period
            between 1 March 2000 and 30 June 2000. As of 1 January 2001 the
            monthly contributory share and terms of payment shall be as detailed
            and stipulated in the contract with the management company.

17.   DELINQUENCY IN PAYMENT

      Without detracting from any right that the lessor may have in accordance
      with this agreement and any legal provision on account of breach of the
      agreement, it is agreed that any case in which the lessee is delinquent in
      payment of any sum that it owes the lessor under this agreement, the
      lessee shall pay to the lessor that amount, linked to the index, as
      stipulated in this agreement (and if there is no base index with regard to
      the sum, the "base index" for this amount shall be the known index on the
      day when the lessee was supposed to have paid the amount), plus arrears
      interest at a rate that is twice the interest rate (including fees and
      expenses) charged by Bank Hapoalim, Ltd., (main Tel Aviv branch) on
      authorized overdraft (hahad) accounts for nonpreferred customers, with
      this arrears interest being computed by the method and manner whereby Bank
      Hapoalim, Ltd., computes during the period of delinquency (including
      compound interest).

18.   DAMAGES, REFUNDS, AND REMEDIES

      18.1  It is agreed that the payments and amounts owed by the lessee and
            the dates for their payment, as well as the provision of full and
            timely guarantees, are a principal condition of this agreement. This
            provision is in addition to any other provision in this agreement
            and its appendices in which various provisions are stated to be
            principal conditions of the agreement.

      18.2  Should the lessee violate any principal condition of this agreement
            and fail to remedy this within fourteen days from the day when it
            received written warning thereof, and in the case where the lessee
            violates any other condition and does not
<PAGE>

            remedy it within 30 days from the day when it receives written
            warning thereof, this shall be deemed to be a fundamental breach of
            the agreement and the lessor shall be entitled to nullify the
            agreement. The nullification shall be executed in the form of a
            written notice delivered to the lessee or sent to it by registered
            mail.

      18.3  Should the agreement be nullified by the lessor, as stated, the
            lessee shall be required to vacate the leased premises within two
            weeks of the day of nullification, and the provisions of section 15
            above shall apply to the vacation of the premises.

      18.4  In addition to any remedy to which the lessor is entitled, in
            accordance with the agreement or any legal provision, on account of
            a violation of this agreement by the lessee, the lessor shall be
            entitled to compensation from the lessee for all damages, losses,
            and diminution of revenues that it may be caused by a breach
            committed by the lessee or by virtue of recourse to any remedy to
            which the lessor is entitled.

            Without detracting from any other right, compensation, or remedy to
            which the lessor is entitled, it is agreed that the lessee shall be
            liable to pay to the lessor daily usage fees for every day of
            delinquency in restoring the leased premises to the lessor in
            accordance with the provisions of section 15 above, in an amount
            equal to one-fifteenth of the monthly rent. The lessor's entitlement
            to the usage fees and the lessee's obligation to pay them shall not
            in any way constitute a grant of any entitlement whatsoever to the
            lessee.

            It is agreed that the lessor shall be entitled to compensation
            agreed upon in advance in the event of the breach of any principal
            condition by the lessee, in an amount equal to the rent due to the
            lessor for six months of tenancy. The amount of this compensation
            has been set by the parties after being assessed by them as
            appropriate, taking account of the length of the term of the lease
            and the special rent conditions set by the lessor in this agreement
            and in consideration of other special conditions agreed to by the
            lessor. The lessor shall be entitled to the agreed upon compensation
            in addition to any compensation, usage fee, entitlement, and remedy
            that may be available to the lessor under this agreement and any
            legal provision.

      18.5  Any sum of any type whatsoever that a party to the agreement may
            have paid instead of the second party shall be refunded by the
            second party to the first party within seven days of a demand by the
            first party, plus linkage differentials to be computed from the day
            of payment until the end of that week; it is however hereby
            explicitly agreed that the lessee shall not be entitled to offset
            any debt that the lessor may owe it under this section and in
            general from any payment that the lessee may owe the lessor.

      18.6  The lessor is entitled to cash in the securities and guarantees
            provided by the lessee under section 19 below, and this in addition
            to any remedy or compensation to which the lessor is entitled under
            this agreement and any provision of law, on the sole condition that
            it has given the lessee written warning of its intention to do so at
            least 14 days in advance.
<PAGE>

19.   GUARANTEES

      19.1  As additional security for the fulfillment of its obligations the
            lessee hereby delivers to the lessor an independent bank guarantee
            in the amount of NIS 122,000 (one hundred twenty-two thousand New
            Israeli Sheqels) (index lined), worded on the model of the document
            that is attached to his agreement as integral part thereof and
            designated Appendix F. The amount of the bank guarantee as of the
            date of the signing of the agreement is equal to the monthly rent
            for five months, plus Value Added Tax.

            The base index for the bank guarantee shall be 106.8 points.

            The bank guarantee shall be payable to the benefit of the lessor and
            shall be valid for one year and three months from the date of the
            signing of this agreement. The lessee undertakes to extend its
            validity as long as the lease remains in force, for an additional
            year; such that the lessor shall always be the beneficiary of a bank
            guarantee as stated and such that the bank guarantee will be in
            force until three months after the expiration of the lease.

            The validity of the bank guarantee shall be extended no later than
            two weeks before its expiration. Should the lessee fail to extend
            its validity the lessor shall be entitled to cash it in.

      19.2  It is agreed that the lessor shall be entitled to cash in the bank
            guarantee in the event that the lessee fails to take possession of
            the leased premises on the date specified in this agreement, or if
            by that date the lessee shall not have met every financial liability
            or has not covered all obligations and debts owed by the lessee
            (both to the lessor and to the management company), or has not
            covered any damage caused it by the lessee, as well as in any case
            of a violation of a principal condition of the agreement by the
            lessee (and this in addition to any remedy to which the lessor is
            entitled under any legal provision and under the agreement), on the
            sole condition that the lessee has received written warning of the
            intention to do so at least 14 days in advance.

            The cashing in of the bank guarantee shall not of itself be
            tantamount to cancellation of the agreement and the lessee shall be
            obligated, immediately after the cashing of the guarantee, to
            deliver to the lessor a new bank guarantee phrased in accordance
            with Appendix F to the agreement, in the amount stated above, and
            which will be in force, all in accordance with the provisions of
            section 19.2 above.

      19.3  The lessor shall return to the lessee the bank guarantee (or any
            balance remaining after it has been cashed) no later than three
            months after the end of the term of the lease, on the sole condition
            that the lessee does not owe any debt or amount whatsoever to the
            lessor as of that date.

      19.4  In order to collect and recover any debt owed by the lessee and to
            guarantee the fulfillment of every obligation incumbent upon the
            lessee (including any debt or obligation of the lessee vis-a-vis the
            management company), the lessor shall be
<PAGE>

            entitled to cash in any security and any guarantee, individually or
            all of them or any portion thereof, and the lessee and any guarantor
            shall have no right to prevent the lessor from so doing. The bank
            guarantees under this agreement are autonomous and not dependent on
            this agreement and in general neither the lessee nor any party that
            led to the taking out of the bank guarantee shall have any right to
            hinder the cashing of the bank guarantee for any cause whatsoever.

      19.5  Any delay in the delivery of the securities under section 19 shall
            entitle the lessor to delay the transfer of possession of the leased
            premises to the lessee, but the term of the lease shall be computed
            from the starting date of the lease as stipulated by the lessor and
            the lessee shall owe rent (and payment to the management company)
            and any liability imposed under it under this agreement as of the
            starting day of the lease or the date stipulated in the agreement,
            even if it has not received possession of the leased premises as
            stated.

      19.6  Each provision of the present section 19 is a principal condition of
            this agreement, the violation of which constitutes a fundamental
            breach of the agreement to which are applicable also the provisions
            of section 18 above.

20.   MISCELLANEOUS

      20.1  The lessee shall pay to the lessor, in connection with and along
            with every payment made to the lessor, Value Added Tax at the rate
            that may be stipulated by law at the time of payment. The lessor
            shall provide the lessee with a tax invoice within the period
            stipulated by law after the payment.

      20.2  The lessee shall bear all expenses of tax stamps on the promissory
            notes. The lessee shall convey to the lessor the amount of the stamp
            tax so that the lessor can have the notes stamped for itself as
            well.

      20.3  The lessee shall be permitted to mount a nameplate in the building
            where the leased premises are located. The size of the nameplate,
            its basic design, and location must receive prior written approval
            from the lessor, and this in addition to any permit that may be
            required under law, all at the responsibility and expense of the
            lessee.

      20.4  The lessee undertakes to abide as appropriate, throughout the term
            of the lease, the provisions of any law that may be in force during
            the term of the lease, with regard to the leased premises, the use
            thereof, the business conducted therein, and any activities there.

            The lessee shall be liable for any damage or expense that the lessor
            may incur as a result of the lessee's failure to meet these
            obligations and the lessee shall be required to indemnify the
            lessor, immediately upon demand, on account of any damage, fine,
            loss, or expense incurred by the lessor.

      20.5  It is agreed that only the actual payment of any amount that the
            lessee may owe the lessor or the actual redemption of a promissory
            note, including rent payments, shall be considered to be an
            appropriate payment. The mere delivery of promissory notes
<PAGE>

            to the lessor, under the provisions of this agreement, or their
            endorsement shall not constitute any form of payment whatsoever.

      20.6  The lessee affirms that it has examined with the planning and
            construction authorities the plans for the project and the leased
            premises and its ability to use the leased premises for the purpose
            of the tenancy; and it has and will make no claims of any kind
            whatsoever with regard to its ability or inability to receive a
            business permit under the law.

            A failure to receive a permit under the law or the voiding of the
            permit shall not entitle the lessee to cancel the lease. It is
            hereby agreed explicitly that the lessor makes no undertaking and
            bears no responsibility vis-a-vis the lessee in anything associated
            with the permit required by the lessee and related to the ability of
            the lessee to make use of the leased premises.

            All outlays, taxes, and mandatory payments required for obtaining
            and extending the permit shall devolve upon the lessee alone. Should
            the lessor incur any costs whatsoever on account of the need for a
            permit, obtaining the permit, or extending he permit, the lessee
            shall be required to refund them to the lessor within seven days of
            the day upon which it is requested to do so by the lessor.

            The lessee's use of the leased premises shall be exclusively for the
            purpose of the tenancy and in accordance with all legal provisions.

      20.7  It is agreed by the parties that only this agreement reflects what
            has been stipulated, what is binding, and what is agreed to by the
            parties. There is not and shall not be any validity to any
            information, document, agreement, or notification that may have been
            given to the lessee by the lessor or on its behalf, if given, before
            the signing of this agreement.

            There shall be no validity to any obligation, condition, waiver, or
            amendment to the agreement unless made in advance and in writing.
            The failure to have recourse to any remedy whatsoever or any
            guarantee whatsoever shall not be considered to be a waiver.

      20.8  The lessor shall be entitled to transfer or pledge its rights under
            the present agreement to some other party or parties, on exclusive
            condition that the rights of the lessee under this agreement not be
            impaired. The lessor shall notify the lessee of this.

      20.9  It is agreed that any payment that the lessee may be required to
            make to the lessor shall be paid by the lessee in the offices of the
            lessor, unless otherwise stipulated in this agreement.

      20.10 It is agreed that the lessee shall be entitled to make use of the
            leased premises in the evening and night as well as on Saturday
            night after the conclusion of the Sabbath, and the lessor affirms
            that it is not opposed to this; however, the hours of activity shall
            be in accordance with all legal provisions. In everything related to
            the operation of project systems at such times or on Saturday night
            the lessee shall coordinate the
<PAGE>

            matter with the management company and the operation of the systems
            and services of the management company (including air-conditioning)
            shall be in return for payment and in accordance with the conditions
            that may be set by the management company. The lessee takes note of
            the fact that for operation of the leased premises and operation of
            the systems and provision of services by the management company at
            times that are not regular working hours and on Saturday night it
            will have to make special payments to the management company
            according to conditions to be set by the management company.

      20.11 By way of sound practice it is hereby emphasized that the project
            will not be operated on Fridays, festival eves, Saturdays,
            festivals, and legal holidays. The lessee takes note of the fact the
            project will be closed at such times and emergency entry to it will
            be possible only through an entry to be determined by the management
            company.

      20.12 Given that the lessee is a limited liability company, it is agreed
            that the lessor shall be entitled to cancel this agreement in the
            event that a receivership order (including a temporary order) or
            liquidation order (including a temporary order) is issued against
            the lessee, and this if the orders have not been annulled within 60
            days of their issuance.

      20.13 It is agreed that judicial jurisdiction in any legal proceedings
            between the parties shall be held exclusively by a sitting in the
            city of Jerusalem.

21.   SPECIAL PROVISIONS

      21.1  The lessee undertakes that the leased premises will always have a
            neat and clean appearance, both in the interior of the leased
            premises and its exterior. The lessee undertakes to keep the leased
            premises clean on a continual basis.

      21.2  The lessee shall not place any furniture, accessories, packages,
            crates, materials, equipment, trash, or objects outside the leased
            premises. The lessee shall make no use of any section of the
            building and project other than for the purpose of access to and
            from the leased premises.

      21.3  The lessee undertakes not to receive deliveries to the leased
            premises other than at the times and by the routes to be determined
            by the management company as stated in the contract with the
            management company.

      21.4  The lessee undertakes not to discard trash, waste, or packages from
            the leased premises other than at the times and by the routes to be
            determined by the management company.

            The lessee undertakes to store all waste, trash, and packages in a
            concealed area inside the leased premises until such time as it is
            entitled to remove them as stated above.
<PAGE>

      21.5  The lessee undertakes not to take any action or make any use of the
            leased premises that may create noise, odors, vibration, smoke,
            contamination, or nuisance.

22.   NOTIFICATIONS

      Any notice from one party to the other delivered to the addresses listed
      below or sent there be registered mail shall be considered to have reached
      its address within 72 hours of its conveyance for delivery by registered
      mail (and in the case of hand delivery, within twelve hours of
      conveyance).

      The lessee shall not convey or dispatch a notice such that the time
      computed for its arrival or delivery falls on Friday or the eve of a
      festival or Saturday or a festival day or the intermediate days of
      Passover and Tabernacles.

      THE ADDRESSES OF THE PARTIES FOR THE PURPOSE OF THIS AGREEMENT ARE AS
      FOLLOWS:

Lessor:     27 Hamered St., Tel Aviv (c/o Isras), or any other address in Tel
            Aviv of which the lessor may provide written notification to the
            lessee.

Lessee:     At the leased premises or 216 Jaffa Road, 94383 Jerusalem (at one of
            these two addresses and each of them). The lessee's address at the
            leased premises will not change.

23.   POSTPONEMENTS

      It is hereby agreed that should the lessor be delayed in completing the
      work and utility supplies in accordance with section 4.2 above and in the
      building beyond 1 March 2000, the date of the transfer of possession to
      the lessee and the starting day of the lease will be postponed until a
      date on which the lessor knows [thus in original; probably should be
      "provides notice"] that it has completed the work and utility supplies.

      Should there occur a delay in the date of the conveyance of possession as
      stated, the lessee shall be liable to pay the rent under this agreement
      only from the new date set by the lessor as the starting date of the
      lease.

24.   EARLY TERMINATION OF THE LEASE

      24.1  It is agreed that on each of the dates listed below the lessee shall
            be entitled to notify the lessor in writing of the early termination
            of its tenancy, in such fashion that the tenancy will conclude on
            the last day of the month of February immediately following the day
            on which the lessor receives written notice from the lessee.

            The following are the dates on which the lessee may submit such a
            notice of early termination of the lease:

            24.1.1      Until 31 August 2003 (for the period after 29 February
                        2004)

            24.1.2      Until 31 August 2006 (for the period after 29 February
                        2007)
<PAGE>

      24.2  Should the lessee submit notice in accordance with section 24.1
            above (hereinafter "early termination notice"), the term of tenancy
            under this agreement shall terminate on the date stipulated in
            section 24.1 above (namely, on the last day of the month of February
            following the early termination notice), all this on condition that
            the early termination notice was submitted in due and timely
            fashion. An early termination notice will be valid only if actually
            delivered to the lessor by 31 of August (on one of the dates
            specified in section 24.1 above).

            Should no early termination notice be delivered by the date stated
            above the term of the lease shall continue automatically.

            Should an early termination notice be delivered to the lessor on a
            date as stipulated above, the tenancy shall be seen as if it had
            been originally arranged for the term ending on the last day of the
            month of February immediately following the delivery of the early
            termination notice, and all provisions of this agreement that apply
            to the end of the term of tenancy shall apply.

      24.3  Should the lessee not submit an early termination notice as stated
            above the following provisions shall also apply:

            24.3.1      The lessee undertakes that no later than 1 September
                        2003 it will convey to the lessor seven promissory notes
                        in accordance with the provisions of sections 6.2, 6.3,
                        and 6.4 above, relating to the period between 1 March
                        2004 and 28 February 2006, with the first promissory
                        note relating to the period from 1 March 2004 until 30
                        June 2004 and the last promissory note relating to the
                        period from 1 January 2006 until 28 February 2006.

            24.3.2      The lessee undertakes that no later than 1 September
                        2006 it will convey to the lessor seven promissory notes
                        in accordance with the provisions of sections 6.2, 6.3,
                        and 6.4 above, relating to the period between 1 March
                        2006 and 29 February 2008, with the first promissory
                        note relating to the period from 1 March 2006 until 30
                        June 2006, and the last promissory note relating to the
                        period from 1 January 2008 until 29 February 2008.

      24.4  Each of the provisions of section 24.3 above is a principal
            condition of this agreement, the violation of which constitutes a
            fundamental breach of the agreement to which are applicable also the
            provisions of section 18 above.

      24.5  In order to avoid any misunderstanding it is hereby agreed, in
            addition to what is stated in section 24.4 above, that should the
            lessee fail to convey to the lessor promissory notes in the amount
            and on the date as stated in section 24.3 above, the lessor shall be
            entitled (in addition to any other right and remedy under the
            agreement and according to law) to inform the lessee in writing that
            the term of the lease will conclude on 19 February immediately
            following the latest date on which the lessee was to have conveyed
            the promissory notes to the lessor.
<PAGE>

            Should the lessor make such notification the term of the lease shall
            be viewed as terminating on the aforesaid date and all provisions of
            the agreement that apply to the end of the term of tenancy shall
            apply to this date.

      24.6  Should the lessee submit an early termination notice in accordance
            with section 24.1, it shall also be entitled to inform the lessor,
            as a separate section in the early termination notice, that the
            tenancy will be terminated not necessarily on the last day of
            February following the date of delivery of the early termination
            notice stated but three months later, that is, on 30 June; on
            condition that along with the early termination notice the lessee
            convey a promissory note (in accordance with the provisions of
            sections 6.2, 6.3, and 6.4, that includes the monthly rent for this
            period, plus Value Added Tax; base index 106.1 points).

            Should the lessee make such notification and convey a promissory
            note as stated, the tenancy shall be considered as if it had
            originally arranged for the period concluding on 30 June following
            the delivery of the early termination notice, and all provisions of
            this agreement that apply to the end of the term of tenancy shall
            apply.

25.   Whereas in order to construct the project and as part of the financing
      thereof by Bank Hapoalim the lessor has pledged its rights in the project
      and the leased premises, it is accordingly agreed that the lessor pledges
      and assigns to Bank Hapoalim, in the form of a lien, all its rights
      vis-a-vis the lessee and hereby gives the lessee an irrevocable order to
      pay the rent and all other payments that are due and may be due it from
      the lessee, under this tenancy agreement, into the lessor's account No.
      696653 at the Kikar Rabin Tel Aviv branch (No. 609) of Bank Hapoalim. The
      lessee's signature on this tenancy agreement constitutes an undertaking on
      its part vis-a-vis the bank to act as stated. The promissory notes
      conveyed by the lessee to the lessor will be deposited by the lessor in
      the aforesaid bank account.

26.   PARKING PRIVILEGES IN THE PARKING FACILITIES OF THE PROJECT

      The lessor confirms that 4 parking spaces (whose numbers are _____ through
      ____, inclusive, two parking spaces in the parking facility in Building B
      and _____ through _____, inclusive, and two parking spaces in the parking
      garage in Building C) will be allocated to the lessee in the parking
      facilities of the project, and this for the term of tenancy, on sole
      condition that the lessee concludes a separate parking agreement with the
      operator of the parking facility, pay the parking fees in accordance with
      the parking agreement, and meet all other conditions of the parking
      agreement.

      It is agreed that the monthly parking fee for each parking space shall be
      NIS 317 (three hundred seventeen New Israeli Sheqels) (plus Value Added
      Tax), linked to the index (base index: 106.8 points), and that this is
      included in the rent stipulated in section 5.1 above.

      At the time of the signing of the present agreement the lessee and lessor
      are also signing a Parking Agreement, but the lessee confirms that the
      "parking facility operator" in accordance with the Parking Agreement will
      be designated by the lessor after the signing
<PAGE>

      of the Parking Agreement, and that any right or obligation of the "parking
      facility operator" shall adhere to the stated "parking facility operator"
      in place of the lessor.

      When the "parking facility operator" replaces the lessor, the lessor shall
      have no obligation with regard to parking and the parking facility, except
      for its confirmation that the lessee is entitled (in the conditions
      enumerated above) to the stated parking spaces and to the usage fees as
      stated.

      In everything related to parking, the provisions of the Parking Agreement
      only shall apply; nevertheless, to the extent that the parking facility or
      any part thereof may be operated commercially, the parking facility
      operator shall bear a proportional share of the maintenance expenses for
      the parking facility, including taxes and municipal rates, in accordance
      with the number of parking spaces commercially available as a share of all
      the parking spaces in the parking facility.

IN WITNESS WHEREOF THE PARTIES HAVE AFFIXED THEIR SIGNATURES

Today, 13 December 1999, in Jerusalem

[company stamp:                     [company stamp:
Har Hotzvim Properties, Ltd.]       BRT Biopharmaceuticals Ltd.]
[signatures: ?? & ??]               [signatures: Moshe Laster & Ira Weinstein]

      HAR HOTZVIM PROPERTIES, LTD.        BRT BIOPHARMACEUTICALS LTD.
            LESSOR                                    LESSEE


[ref. heh het - shin kaf B-6]