Document:

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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
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                           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]<PAGE>

                                                                   EXHIBIT 10.20

                               MANAGEMENT CONTRACT

               Drafted and signed in Jerusalem on 13 December 1999

Between:  PARK MEIR MANAGEMENT COMPANY LTD.
          27 Hamered St., Tel Aviv (in the offices of Isras)
          (hereinafter "THE COMPANY")

And:      BRT BIOPHARMACEUTICALS LTD.
          216 Jaffa Road, Jerusalem
          (hereinafter "THE TENANT")

Whereas   The Tenant has leased unit B/3/101 in Building B in the Ramot Meir
          project, Har Hotzvim, Jerusalem, in accordance with a tenancy
          agreement dated 13 December 1999 with "the Owner" (as this is defined
          below);

And whereas  The Company has been designated by the Owner as the management and
          maintenance company of the Project (as this is defined below) and
          accepts responsibility for providing the Project with management and
          maintenance services as specified in this contract;

And whereas  The Tenant agrees that the management and maintenance services for
          the Project specified in this contract will be provided by the
          Company;

And whereas  This contract arranges the mutual obligations of the parties in
          everything concerning the provision and receipt of management and
          maintenance services in the Project and everything concerning the
          Tenant's participation in the management and maintenance costs;

And whereas  The parties have agreed on all conditions and undertakings with
          regard to the management and maintenance of the Project;

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  The headings and names given to the sections of this contract have
          been inserted to facilitate reading the agreement and are not part of
          the contract and will not be used to interpret the contract.

2.   INTERPRETATION AND DEFINITIONS

     In this contract, the following terms shall be given the meanings listed
     alongside them, as follows:
<PAGE>

THE OWNER             Har Hotzvim Properties Ltd.

TENANCY AGREEMENT     The tenancy agreement dated 13 December 1999 between the
                      Tenant and the Owner

THE PROJECT           The Ramot Meir project, being erected on the land known as
                      parcel 110 in block 3241, in the Har Hotzvim Industrial
                      Zone, Jerusalem, including everything built and existing
                      thereon, including all structures, buildings, wings, car
                      parks, and open areas, and every area, installation, and
                      system on the property whether existing on the day of the
                      signing of this contract or such as may exist in the
                      future. A sketch of the project is attached to this
                      contract as an integral part thereof and designated
                      Appendix A. Marked on the sketch are Building A (existing
                      building), Building B (currently under construction),
                      Building C (currently in an advanced stage of planning),
                      and Building D, planned to be erected in the future.

THE UNIT, THE UNITS   Each one of the units in the project in each one of the
                      buildings A, B, C, and D, according to the division that
                      has been made or will be made by the Owner, and that are
                      intended to be leased or assigned by the Owner. The Units
                      shall not include: the covered parking facilities in the
                      Project, as well as "the Management Company areas" and
                      "Public Areas," even if restricted usage rights to them
                      have been conveyed (such as kiosks for the sale of various
                      items).

PUBLIC AREAS          All of the areas (built up or otherwise) in the Project
                      and every building that is part of it (and every part
                      thereof) that are not "the Units" and are not "Management
                      Company areas" and are not the covered parking facilities
                      in the project. The definition of "public areas" Inter
                      will include, inter alia, the outside walls and roofs of
                      every building and structure in the project, all the
                      corridors, stairwells, elevators, open passageways and
                      corridors, open space, plazas and gardens, unroofed
                      parking spaces (if any); public services, shelters, paths,
                      and any system of the "project systems."

"MANAGEMENT COMPANY   Surfaces, spaces, meeting halls, rooms structures, and
AREAS"                parts of structures that are intended for the use of the
                      Company in the context of its provision of management and
                      maintenance services to the Project, including store
                      rooms, offices, cubicles, transformer, water, and
                      electricity rooms, and every other part of the project
                      used only by the Company.

"PROJECT SYSTEMS"     All of the systems and installations in the project that
                      are not specifically attached exclusively to a particular
                      unit or particular
<PAGE>

                      units (in part of a building), including main
                      air-conditioning systems and installations, electrical
                      systems, telecommunications, water, electromechanical
                      systems, control/monitoring systems, elevators, lighting
                      systems, and sewage and drainage systems.

"TENANT'S UNIT"       Unit No. _____ in Building B in the Project, which has
                      been leased to the Tenant by the Owner. It is agreed that
                      the area of the Tenant's Unit for the purposes of this
                      contract is 400 square meters.

"MANAGEMENT AND       Each of the mandatory services, optional services, and
MAINTENANCE SERVICES" special services enumerated in section 3 of the contract
                      and the other sections of the contract and every part
                      thereof.

3.   MANAGEMENT AND MAINTENANCE SERVICES

     3.1  The Company shall be responsible for performing, on its own or by
          means of outside contractors, each one of the following services
          (hereinafter "mandatory services"):

          3.1.1   Management and maintenance services, the operation, regular
                  upkeep, maintenance, management, restoration, and repair of
                  the public areas and project systems.

          3.1.2   Cleaning public areas, removing trash from main facilities,
                  gardening and irrigation, lighting, services to improve the
                  appearance of the public areas, operation of public facilities
                  (lavatories).

          3.1.3   Activation and deactivation of systems (Project systems) in
                  accordance with the seasons of the year or hours and days, as
                  set by the Company.

          3.1.4   Insurance, as specified in section 10 below, and the payment
                  of deductibles on account thereof.

          3.1.5   The maintenance of a central office (including a telephone
                  line to it) where all topics of management and maintenance
                  services for the project will be coordinated. The office hours
                  shall be the working hours designated by the Company.

          3.1.6   The provision of each one of the above services and activities
                  in the Management Company areas.

     3.2  The company is entitled to provide, on its own or through outside
          contractors, each of the following services (hereinafter "optional
          services"):

          3.2.1   Security and monitoring services of the public areas, the
                  Management Company areas, and the project systems, including
                  surveillance of all traffic entering and leaving the Project.
<PAGE>

          3.2.2   Services and actions that are generally provided by the house
                  committee of a condominium, including the maintenance of order
                  in the Project and the drafting of bylaws for the Project.

          3.2.3   Central or distributed information services for the Project.
                  Surveillance of control/monitoring systems, public address and
                  alarm services, the locating of malfunctions, the locating of
                  fires and break-ins, etc.

          3.2.4   The erection of directional signs and main signs providing
                  directions to the various buildings and parts of the project,
                  as well as directional signs and identifying signs on the
                  buildings of the project, and the hanging of other signs,
                  including determination of the design, size, and location of
                  signs belonging to the various tenants of the project, as well
                  as maintenance and restoration of the signs in the project.

          3.2.5   Cleaning of the outside of the windows of the project.

          3.2.6   Operation, regular upkeep, preventive maintenance,
                  restoration, repair, and insurance of systems and facilities
                  that are shared by several units in the project.

          3.2.7   Provision of advertising services and erection of signs for
                  the Tenant in the project.

          3.2.8   Services in a matter required by law (or at the demand of
                  legally constituted authorities) relating to the project and
                  relating to any part thereof (but not relating to the units
                  themselves).

          3.2.9   Any other service in the project and any part thereof, in the
                  Management Company areas, in the public areas, and in the
                  project systems that the Company may, at its exclusive
                  discretion, decide to operate as a service that is required or
                  as a service that is related to the services that the Company
                  must or may provide.

     3.3  The Company shall be entitled (but not required) to provide each of
          the optional services enumerated in section 3.2 above, or any part
          thereof, at its discretion and at times it may determine, and it is
          agreed that the Tenant shall not interfere in any manner whatsoever
          with the ability of the Company to decide and to provide each of the
          optional services or any part thereof.

     3.4  It is agreed that the Tenant shall not request and shall not receive
          any service whatsoever of the type of services enumerated in section
          3.1 and section 3.2 other than from the Company.

     3.5  It is hereby emphasized that except for the services enumerated in
          sections 3.1 and 3.2 above, the company will engage (as optional
          services) in the management of the Ramot Meir project and the
          promotion of its interests. It may also rely on the service of outside
          service providers with regard to the management and
<PAGE>

          maintenance of the project, including bookkeeping, accountants,
          attorneys, planners, designers, engineering consultants, and insurance
          consultants, and any other outside service. Each one of these services
          provided to the Company shall be considered to be an "optional
          service" of the Company that is provided to the project.

     3.6  If water meters are not installed for the various units in the
          building where the Tenant's unit is located, according to a decision
          by the Owner, the Management Company shall collect on behalf of the
          Owner usage fees for water, as set pro rata for each unit. The pro
          rata water usage shall be determined on the basis of the overall water
          usage as indicated by the water meter of the building (in which the
          Tenant's unit is located), with this usage being divided among the
          units in proportion to the area assigned to each unit in the building.

          The aforesaid notwithstanding, should it become apparent to the Owner
          that the water usage by the units of the building is negligible and
          limited, the Owner shall be entitled to determine that the water
          supply to the units in the building will be computed as part of the
          mandatory services provided by the Company; and in this case the
          payments required for water usage by each of the units shall be deemed
          to be part of the "actual expenses," in accordance with section 6.1
          below, and will be included in the contributory share of the
          "expenditures of the Company" that the Tenant must pay under this
          contract.

4.   MANNER OF PROVISION OF THE SERVICES

     In order to implement the services that the Company is required or may
     provide, it shall operate as follows:

     4.1  The Company undertakes to staff its main office in the Project during
          working hours, which will be determined by it, in order to deal with
          requests by tenants.

     4.2  The Company undertakes to employ a person who will serve as service
          manager for the Project.

     4.3  The Company undertakes to set up, for the purpose of providing
          services under this agreement, teams of employees and/or teams of
          contractors and/or outside service providers who are professionals in
          each of the domain in which it is required to provide services.

     4.4  The Company shall organize an apparatus of employees and contractors
          in order to organize its services, including bookkeepers, clerical
          workers, supervisors, consultants, maintenance managers, and so on.

     4.5  The Company shall establish contractual relations with providers of
          repair services in everything connected with Project systems or some
          part thereof in order to receive periodic maintenance services.

     4.6  The Company, at its discretion, shall see to the maintenance of an
          inventory of spare parts for the Project systems that can be replaced
          with relative ease.
<PAGE>

     4.7  The Company (with the approval of the Owner) is entitled to draw up
          "project bylaws" that will set general rules for maintaining order and
          sound management of the Project. The "project bylaws" shall apply to
          all tenants in the project. The Company shall be entitled to amend and
          modify the project bylaws from time to time. In the context of the
          project bylaws the Company shall be entitled also to stipulate hours
          and times for the removal of trash, instructions concerning the design
          and location of signs, the appearance of building facades, modes of
          assuring order and cleanliness, and so on.

     4.8  The regular maintenance services, cleaning services, and other
          services shall be provided by the Company during regular working
          hours, with a frequency and rate set at the discretion of the Company
          or the Owner, while scrupulously maintaining the clean and attractive
          appearance of the public areas.

     4.9  The Company or the Owner is entitled to specify hours and days for the
          operation of the central air-conditioning systems in the public areas
          and other central air-conditioning systems.

     4.10 The lighting systems in the public areas inside the buildings and the
          project will be operated such that these will be illuminated in
          reasonable fashion during daytime and nighttime hours to an extent to
          be determined by the Company. The outside lighting systems will be
          operated during nighttime hours in a scope to be determined by the
          Company.

     4.11 Maintenance work, repairs, replacement of parts, and engineering work
          shall be performed within a reasonable lapse of time and during
          regular working hours, but in exceptional cases these will be
          performed during hours when there is no activity in the Project that
          might be disturbed as a result of the work.

     4.12 The wages, conditions, and remuneration that the Company will extend
          to its employees, contractors, and outside service providers shall be
          reasonable and in accordance with the normal practice.

     4.13 The Company shall be entitled to remove any sign, advertisement, or
          installation of the Tenant's that was erected or designed without the
          Company's agreement.

     4.14 It is hereby made clear that even if the Company provides (itself or
          by means of outside contractors) security and surveillance services,
          it shall not be considered to be the "watchman" of the Tenant's unit
          or the units in the project (and their content) or of the project for
          the purposes of the Watchmen's Law 5727-1967, and the Company shall
          not bear the responsibility under this law. The purpose of the
          surveillance and supervision shall be in the domain of maintaining
          order in the project. Any tenant or unit that requires security
          services will have to see to them on its own.

     4.15 It is hereby made clear that at the discretion of the Company and its
          determination, various systems of the Project systems and various
          services of the management and maintenance services will not be
          provided and will not be performed in hours that
<PAGE>

          are not regular working hours (8 A.M. to 6 P.M.) on weekdays and 8
          A.M. to 1 P.M. on Fridays and festival eves). Should the Tenant
          request the operation of some of these systems or to receive a Company
          service during hours that are not the aforesaid hours, then, if the
          Company is willing to comply with the Tenant's request, the Tenant
          shall be required to make a special payment to the Company for such,
          in accordance with a tariff that the Company may set from time to
          time. Such service and the operation of systems as stated shall be
          considered to be a special service to the Tenant.

     4.16 The Tenant takes note of the fact that is possible that from time to
          time, intentionally or unintentionally, as a result of the services of
          the Management Company or as a result of some other factor, there may
          be the suspensions, disruptions, delays, and malfunctions in anything
          associated with the supply of electricity, water, generators,
          elevators, air-conditioning, maintenance services, security, and
          anything else associated with the Company's services. The Tenant
          undertakes not to demand any compensation or indemnification from the
          Company (and/or from the Owner) on account of such and shall not
          demand any restitution or compensation on their account. The Company
          affirms that it will act to the best of its ability to take all
          reasonable steps that may be required, to the extent possible, to
          prevent and limit malfunctions as stated.

5.   OBLIGATIONS OF THE TENANT

     The Tenant hereby commits itself vis-a-vis the Company, in addition to all
     other obligations under the contract, as follows:

     5.1  Not to commission services enumerated in this contract from any party
          other than the Company and not to receive the services enumerated in
          this contract from any party other than the Company; and this both in
          everything associated with the area of the units as well as in
          everything associated with the other areas of the project and
          everything associated with any of the system in the Tenant's unit and
          Project systems; all in accordance with the provisions of sections 3.4
          and 3.5 above.

     5.2  To refrain from any act of commission or omission that is likely to
          interfere with the Company's ability to meet its obligations under
          this contract or under management contracts signed with other parties,
          and to refrain from any act of commission or omission that is likely
          to interfere with the Company's ability to provide any service of the
          services under this contract. The Tenant further undertakes to abide
          by the provisions of the project bylaws that may be determined by the
          Company (and as they may be amended from time to time); the Tenant
          undertakes not to place installations, equipment, trash, crates, or
          any other object outside the area of the Tenant's unit and not to put
          up any signs whatsoever that have not been approved by the Company;
          the Tenant further undertakes to cooperate with the Company and its
          representatives in every matter associated with the services of the
          Company and to comply with their requests.
<PAGE>

     5.3  To permit the Company and anyone referred by it enter the Tenant's
          unit during working hours (or at other times if so agreed by the
          parties) in order to provide any of the services under this agreement
          (and this both with regard to services that the management company
          must provide to the Tenant or some other tenant in the project as well
          as with regard to services that related to the Project and public
          areas, including roofs and outside walls).

     5.4  To pay to the Company its "contributory share" in the "expenditures of
          the Company" on the dates and in the amounts stipulated in section 6
          below and anywhere else in the contract. It is agreed that this
          obligation of the Tenant's is absolute and unaffected if it does not
          actually occupy the "tenant's unit" or does not use it or the public
          areas or the Project systems or any part thereof or if it does not
          benefit from the services of the Company or does not receive them for
          any reason whatsoever.

     5.5  To deposit with the Company a bank guarantee as security for payment
          of the contributory share by the Tenant, in accordance with section
          6.6 below.

     5.6  The Tenant undertakes to pay to the Company the remuneration to which
          it is entitled under this contract with regard to any service that the
          Company may provide to the Tenant or with relation to its unit. The
          remuneration shall be paid to the Company at a time to be determined
          by the Company.

     5.7  To pay to the Company Value Added Tax in addition to any payment that
          it must make to the Company under the agreement.

     5.8  The Tenant confirms and agrees that the Company (or someone designated
          by it) shall constitute the "house committee" if the project or some
          part thereof is registered as a condominium.

6.   CONTRIBUTORY SHARE IN THE EXPENDITURES OF THE COMPANY

     6.1  In the present section and in the present contract the following terms
          shall have the meaning as indicated:

          "EXISTING UNITS" - All of the units (including the Tenant's unit) that
          already existed in the Project and in any part thereof at the time of
          the provision of management and maintenance services by the Company
          under the present contract, which are units in which all work has been
          completed and they are fit for operation for their intended purpose,
          even if they have not yet been occupied. This does not however include
          the parking facilities in the project and does not include the
          Management Company areas and public areas.

          By way of sound practice it is hereby made plain and agreed that an
          "existing unit" that has not yet been leased out by the Owner as well
          as an "existing unit" that has been vacated by its lessee or tenant
          (other than the Owner) shall not be considered to be an "existing
          unit" or one of the "existing units," and no contributory share shall
          be paid on account of such a unit and the "proportional share" as
          stipulated below shall
<PAGE>

          be computed without this unit. However, if as a result of the
          nonleasing by the Owner or as the result of the vacating of the unit
          or units by their tenants or occupiers (other than the Owner) the area
          of "existing units" falls below 75% of the total area of the units
          that were fit to be included as "existing units" were it not for the
          nonleasing or vacating thereof, the Owner shall pay the contributory
          share in the expenditures of the company (as stipulated below) on
          account of areas to make up the 75% (seventy-five percent) stated
          above. The Owner shall not be responsible for any contributory share
          in the event that the area of the "existing units" (without units that
          have not yet been leased or have been vacated as stated) exceeds 75%
          of the area of the units that are fit to be included as existing
          units.

          "ACTUAL EXPENDITURES" - All expenditures without exception made by the
          Company, including those associated with the provision of mandatory
          services and optional services, whether fixed or variable, as well as
          all expenditures made by the Company on account of the areas of the
          covered parking facilities in the project (Buildings B and C) and on
          account of their operation; without detracting from the stated
          provisions, it is agreed that "actual expenditures" shall be also and
          include the salaries of its employees who are associated with the
          provision of the services (and including social benefits and ancillary
          conditions), payments to contractors and subcontractors, outlays for
          the purchase of materials, equipment, facilities, and media (including
          the overhaul and/or replacement of equipment, facilities, and
          accessories as needed), all as may be required in order to provide
          management and maintenance services as well as outlays to lease and
          maintain the Company's office and storerooms in the Project, financing
          costs (including on account of the services, on account of the
          equipment, and on account of fixed assets), depreciation and
          [translated as written] on equipment and facilities, motor vehicle
          maintenance, insurance, payments under deductible clauses, payment of
          taxes, municipal rates, and other mandatory payments that relate to
          the public areas, the covered parking facilities, the Management
          Company areas, and Company services (excluding taxes and mandatory
          payments on Company profits), as well as a closed reserve fund for the
          overhaul and/or replacement of equipment, facilities, and accessories,
          as well as the fees of the accountant and bookkeepers (who audit and
          maintain the Company's books and the accounts that will be submitted
          to the holders of the units), as well as general administrative
          expenditures and the like, legal expense, and fees to attorneys and
          other service providers. "Actual expenditures" shall also include
          future obligations of the Company related to any matter enumerated
          above.

          "PROPORTIONAL SHARE" - A share to be computed on the basis of the
          ratio between the area of the Tenant's unit and the overall area of
          all the "existing units" at that time in the project and every part
          thereof. The area of the Tenant's unit and the overall area of all the
          existing units are computed according to the key determined by the
          Owner and that will be displayed in the offices of the Management
          Company.

          "EXPENDITURES OF THE COMPANY"" - means the Actual Expenditures plus
          15% of the Actual Expenditures.
<PAGE>

     6.2  The Tenant undertakes to pay the Company its share of the
          "expenditures of the Company"; this shall be the proportional share
          (based on the "Tenant's unit") of the "expenditures of the Company"
          (above and hereinafter "the contributory share"). The Tenant
          undertakes to pay the Company its contributory share starting on 1
          March 2000 and to continue paying it until the day on which it
          actually restores possession of the Tenant's unit to the Owner, in the
          manner and method stipulated in the tenancy agreement between the
          Tenant and the Owner.

     6.3  The Tenant shall pay its contributory share in the "expenditures of
          the Company" in quarterly payments, every three months in advance. The
          Company shall determine from time to time a realistic and cautious
          estimate of the anticipated "expenditures of the Company" (hereinafter
          "the estimate"), and the quarterly payments will be set provisionally
          on the basis of this estimate.

          It is agreed that these payments shall be made each year on the first
          day of the months of January, April, July, and October.

     6.4  From time to time (but at least once a year) the Company will examine
          the actual expenditures really made vis-a-vis the estimate and draw up
          an "updated expenditure report" for the period of the estimate. Should
          it become clear that the estimate was lower than its real expenditures
          (as presented in the updated expenditures report), it will send the
          Tenant a bill to cover the difference; the Tenant undertakes to pay
          this bill to the Company on the first date thereafter stipulated for
          the payment of the quarterly contributory share.

          Should it become apparent from the updated expenditures report that
          the quarterly payments (under section 6.3) were greater than the
          amount that the Tenant should have paid, the Tenant's account with the
          Company will be credited as of the first day thereafter stipulated for
          the payment of the quarterly contributory share.

     6.5  To the differentials according to section 6.4 above will be added
          linkage differentials to the Consumer Price Index, to be computed with
          regard to each month in the period covered by the "updated
          expenditures report."

     6.6  To guarantee payment of the contributory share in the "expenditures of
          the Company," the Tenant conveys to the Company an independent bank
          guarantee in the amount of NIS 29,000 (twenty-nine thousand New
          Israeli Sheqels) (including 17% Value Added Tax). The guarantee shall
          be index-linked (base index 106.8 points, published on 15 November
          1999). The guarantee shall be phrased as in the sample in Appendix E
          to the Tenant's tenancy agreement with the Owner.

          The Tenant undertakes not to take any step whatsoever to hinder the
          ability of the Company to cash the bank guarantee.

          The Tenant undertakes that the Company will always be in possession of
          a bank guarantee of the stated type and in the event that the Company
          cashes the guarantee in its possession, or any part thereof, the
          Tenant undertakes to make up the amount of the guarantee or to provide
          a new bank guarantee as stated.
<PAGE>

     6.7  It is agreed that the Company alone shall be entitled to any income or
          any revenue that the Company may have other than in relation to the
          provision of mandatory services (section 3.1 above) and other than in
          relation to the optional services (section 3.2 above). Any revenue or
          income as stated shall not be offset against the Actual Expenditures.

     6.8  It is agreed that the provisions of the present contract in general
          and the provisions of the present section 6 in particular shall always
          be interpreted in such fashion that there will not be imposed on the
          Company any input or cost with relation to its services under the
          present contract and that all its expenditures plus 15% as stated will
          be covered by the tenants (including the Owner if it is in possession
          of an existing unit on account of which it is obligated to bear a
          "contributory share" as stated in section 6.1 (second paragraph of the
          definition of "existing units").

     6.9  In the event of any ambiguity or disagreement concerning the
          assignment of any service or expenditure, the service and expenditure
          shall be included as "actual expenditures."

7.   BOOKKEEPING

     7.1  The Company undertakes to maintain separate books of account relating
          to "actual expenditures," its services, and its activities in the
          project. The Company will also maintain a ledger card for each unit in
          the project. The books of account will be audited and approved by an
          accountant to be designated by the Company for this purpose.

     7.2  In accordance with arrangements to be determined by the Company, the
          Tenant will be entitled to receive from the Company and the accountant
          explanations about everything related to the books of account and
          documents that relate to the "actual expenditures."

8.   DELINQUENCY AND LINKAGE

     8.1  Without detracting from any right that the Company may have under this
          contract and any legal provision on account of breach of the contract,
          it is agreed that any case in which the Tenant is delinquent in
          payment of any sum that it owes to the Company under the present
          contract, the Tenant shall pay to the Company that amount linked to
          the index, as stipulated in the present contract (and if with regard
          to the sum there is no base index, the "base index" for this amount
          shall be the known index on the day when the Tenant was supposed to
          have paid the amount), plus arrears index 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 the arrears (including compound interest).
<PAGE>

     8.2  The Company reserves the right to stipulate that the amount in arrears
          will be paid plus linkage differentials and 12% annual interest (it
          too index linked), instead of the interest stipulated in section 8.1
          above.

     8.3  In the present contract, "indexation" means linkage to the Consumer
          Price Index published by the Central Bureau of Statistics and Economic
          Research. The computation of linkage according to the present contract
          shall be made according to the "known index."

     8.4  Revenues from arrears interest or linkage (sections 8.1 and 8.2 above)
          shall not be offset against the amount of the "actual expenditures."

9.   MISCELLANEOUS

     9.1  A Tenant who has rights of possession (lessee or sublessee) in a unit
          in the "buildings" shall not be entitled to transfer its rights in the
          unit unless it has paid all its debts on account of the contributory
          share in the "expenditures of the Company" and on condition that the
          party that receives its rights conclude a management contract with the
          Company. The management contract, in this case, will be recorded in
          the land registry office as a condition of the lease.

     9.2  The Tenant affirms that in the event that it violates terms of the
          present contract it will be considered to have violated its agreement
          with the Owner and gives an irrevocable instruction to the Owner to
          act according to the provisions of that agreement that deal with
          breach of the agreement (including cashing of guarantees and
          cancellation of the agreement).

     9.3  With the signing of this management contract the Owner is seen to have
          carried out all of its obligations vis-a-vis the Tenant in everything
          associated with management and maintenance of the Project. It is
          further agreed that in everything connected with management,
          maintenance, and the provision of services under the tenancy agreement
          only the provisions of the present contract shall apply and only with
          regard to the Tenant and the Company.

     9.4  The Company is entitled to transfer its liabilities and rights under
          this management contract to another party to be determined by the
          Owner and is entitled to meet its obligations (in a whole or in part)
          by means of contractors and by means of outside service providers.

     9.5  Deposits and funds belonging to the Tenant that may be held by the
          Company, if any, shall not be included in the system of accounts under
          section 7.1 above. Income and expenditures related to such deposits
          and funds shall be at the responsibility or to the credit of the
          company along.

     9.6  It is agreed that the Company is entitled to require the Tenant to
          make any repair in the Tenant's unit and any repair of a system or
          installation associated with its unit or associated with particular
          units including the Tenant's unit; the Company is further entitled to
          determine that it will perform the required repairs as stated at its
          own
<PAGE>

          initiative and without the separate consent of the Tenant. Every
          service of this sort by the Company shall be deemed vis-a-vis the
          Tenant to be a service provided to it on a private basis and at its
          commission, and the Tenant shall be obligated to pay the Company on
          demand the rate (or price) of the repair.

     9.7  With the approval of the Owner, the Company is entitled to determine
          that the costs and expenditures related to the covered parking
          facilities, in whole or in part, will not be included in the "actual
          expenditures." The Tenant shall not, however, be entitled to impose
          this upon the Company in any fashion whatsoever.

10.  INSURANCE

     The Company undertakes to take out insurance as stated in section 3.1.4 and
     to take out each one of the policies listed below and in accordance with
     the following provisions:

     10.1 The Company will take out the "Company insurance" as detailed in
          section 11 (and in Appendix E) to the tenancy agreement.

          To avoid any doubt it is made plain that the Tenant will take out the
          insurance required of it in section 11 of the tenancy agreement.

     10.2 To take out additional insurance at the discretion of the Company and
          to reduce such insurance or a portion thereof at the discretion of the
          Company.

     10.3 Insurance premiums and every other outlay that the Company and Owner
          may have in connection with the "Company insurance" (under Appendix E
          to the tenancy agreement) and in connection with other insurance taken
          out by the Company and/or by the Owner shall be considered to be
          "actual expenditures" for the purposes of section 6 above.

11.  ADDRESSES AND NOTIFICATIONS

     The Company's address for any matter related to this management contract is
     the management office in the project.

     The Tenant's address is the Tenant's unit.

     Any notice from one party to the other sent by registered mail shall be
     considered to have reached its address within 72 hours of its conveyance
     for delivery by registered mail, and a written notice delivered by hand
     shall be considered to have reached its destination 24 hours after its
     delivery.

12.  SPECIAL REMEDY IN THE EVENT OF A BREACH OF AGREEMENT BY THE TENANT

     In addition to every right available to the Owner and the Company, it is
     agreed that in the event of a breach of contract by the Tenant the Company
     shall be entitled to suspend the provision of its services to the Tenant,
     in a whole or in part, without thereby detracting from the obligation of
     the Tenant to continue to pay its contributory share in the
<PAGE>

     expenditures of the Company. In the context of this suspension of service
     the Company will be entitled to deny the Tenant use of portions of the
     public areas, including elevators, stairwells, air-conditioning, lighting,
     and more.

13.  TERM OF THE AGREEMENT

     The present contract takes effect on the date of its signing by the parties
     and shall remain in effect as long as the Tenant is a lessee or sublessee
     of its unit. In the case that the Tenant is leasing the unit from the
     Owner, the present contract shall remain in effect as long as the Tenant
     retains possession of the Tenant's unit or as long as the lease remains in
     effect (which ever is later).

     The Company shall return to the Tenant the bank guarantees or any sum that
     may remain in the hands of Company after it has been cashed only after the
     Tenant has paid off all debts to the Company, including its debts until the
     end of the contract term that may be discovered later with the
     determination of its real actual expenditures (according to the first
     paragraph of section 6.4 above).

14.  Notwithstanding what may be stated anywhere in the contract or the tenancy
     agreement, the Tenant shall not be entitled to offset any obligation that
     it may have vis-a-vis the Company or vis-a-vis the Owner against any
     obligation or debt that the Company or the Owner may have vis-a-vis the
     Tenant under the contract and/or under any contract or other obligation in
     general and under the tenancy agreement in particular. The Tenant's
     obligation under this management contract is independent and absolute and
     the Tenant shall be obligated to satisfy them unconditionally, and there
     shall be no reduction thereof for any cause whatsoever even if the Tenant
     has financial or other rights vis-a-vis the Owner or vis-a-vis the Company
     or vis-a-vis other parties on account of any matter including on account of
     the contract, on account of the tenancy agreement, on account of the
     project, or anything related thereto.

15.  The Company affirms that it has read the tenancy agreement and agrees with
     its provisions.

IN WITNESS WHEREOF THE PARTIES HAVE AFFIXED THEIR SIGNATURES, TODAY, 13 DECEMBER
1999, IN JERUSALEM.

[company stamp:                      [company stamp:
Park Meir Management Company Ltd.]   BRT Biopharmaceuticals Ltd.]
[signatures:  ?? & ??]               [signatures:  Moshe Laster & Ira Weinstein]

           THE COMPANY                            THE TENANT

[Writ of guarantee crossed out and not translated]
<PAGE>

Name:  BRT
Address:

[added by hand] copy

To:
Bank Leumi le-Israel Ltd.
Branch:  Mahane Yehuda

                                                                  Date: 15/12/99

[stamp:  Bank Leumi Le-Israel Ltd.
Business Branch - Mahane Yehuda, Jerusalem
15-12-1999
913 RECEIVED 913]
                        Re: REQUEST TO ISSUE A GUARANTEE

Please issue a guarantee/obligation (hereinafter "the guarantee") in accordance
with the following form and details:

1.   Name of beneficiary: Har Hotzvim Properties Ltd. (indicate the name of the
     person or corporation that will be the beneficiary of the guarantee)

2.   Address of the beneficiary

3.   Amount of the guarantee:  29,000--

4.   Name of maker: BRT Biopharmaceuticals Ltd. (indicate the name of the person
     or corporation on whose behalf the guarantee will be issued)

5.   With reference to:  compliance with a management contract

6.   Validity of the guarantee: 31/3/2001 (indicate the date to be inscribed on
     the guarantee as the last date for reception of the demand by the bank)

7.   Indexation terms:  Consumer Price Index 10/99

8.   Remarks:

The commission for the guarantee shall be at the rate of 2.6% per annum of the
amount of the guarantee (including interest, indexation differentials, or
exchange-rate differentials, if any) but in no case less than the sum of
NIS___*.

Please debit thereupon our account with your number 121600/19.

In addition, we are aware that we will be charged a commission for drafting
documents in the amount of NIS 100.

What is stated in the obligation we have signed for you with relation to the
issuance of the guarantee and/or indemnity by you shall also apply to the above
the guarantee (and to extensions of its validity if any).

*minimum commission as this appears in the list of commissions.

[company stamp:  Park Meir Management Co. Ltd.]   [signature] IRA WEINSTEIN
                                                  [company stamp:  BRT
                                                     Biopharmaceuticals Ltd.}

                                                          Customer's Signature

--------------------------------------------------------------------------------
For use by the branch

Guarantee No.              File No. _____

Total obligo in guarantees _______  Approval by branch management ________

Securities offered ________         Approval by district management, dated _____

Remember that the customer must sign (on the copy of the guarantee that remains
in the branch) the guarantee document.
<PAGE>

 [Protocol of a Meeting of the Board of Directors - in English, not translated]
<PAGE>

             SPECIAL APPENDIX TO THE TENANCY AGREEMENT/REMEASUREMENT

LEASED PREMISES:  UNIT NO. _____

LESSOR:           HAR HOTZVIM PROPERTIES LTD.

LESSEE:           BRT BIOPHARMACEUTICALS LTD.

1.   In everything related to the area of the leased premises, as stated in
     section 1.2.4 of the tenancy agreement signed by the parties, the parties
     agree that after conveyance of possession of the leased premises the lessor
     will perform a measurement of the net area of the leased premises.

2.   The "net area of the leased premises" means: the area of the leased
     premises including the entire area of the leased premises enclosed by the
     outside walls of the eased premises, including the area of the
     cross-section of the outside walls of the building and including the area
     of the cross section of the outside wall of the leased premises located in
     the interior of the building; but an outside wall shared with other leased
     premises (and only other leased premises) shall be computed at one-half of
     the area of its cross section. (The term "cross section" refers to a
     horizontal cross section at the level of the floor.)

     The "net area of the leased premises" shall be the basis for the
     computation of the agreed area of the leased premises for the purpose of
     the tenancy agreement and for the purpose of section 1.2.4 of the tenancy
     agreement.

     It is agreed that the "gross area of the leased premises"--namely, the area
     that will be computed as the agreed area of the leased premises for the
     purpose of the tenancy agreement, shall be that area such that subtracting
     18% from it yields an area equal to the "net area of the leased premises."

     For example: if the "net area of the leased premises" is 1,230 square
     meters, then the "gross area of the leased premises" is 1,500 square
     meters.

3.   "The gross area of the leased premises" obtained through the computation in
     this special appendix shall be the agreed-upon area that shall be
     considered to be included in section 1.2.4 of the tenancy agreement; and
     this in-place of the area currently stated in the tenancy agreement.

4.   The amounts of the monthly rent as well as the amounts of the promissory
     notes in the tenancy agreement shall be modified in accordance with the
     change in the "gross area of the leased premises" and in proportional
     fashion.

5.   The lessee undertakes to convey to the lessor new promissory notes
     according to the principles of the tenancy agreement, in their new value,
     should it become apparent that there is a change in the "gross area of the
     leased premises" as stated above. This provision is a principal condition
     of the tenancy agreement.
<PAGE>

     Until the lessee conveys to the lessor new promissory notes as stated, the
     lessor shall present for payment the promissory notes in its possession at
     that time and the lessee shall have no right to protest.

6.   Following the measurement and modification of the "gross area of the leased
     premises" as stated, if there is one, the lessor shall issue written
     notification to the lessee concerning the amendment of the relevant
     sections in the tenancy agreement, and this notice by the lessor shall bind
     the parties and shall be an integral and binding part of the tenancy
     agreement.

7.   The lessee reserves the right to challenge, within one month, a
     notification by the lessor under section 6 above, in the form of the
     submission of a competing measurement of the "net area of the leased
     premises" performed (at the lessee's expense) by a qualified surveyor. The
     dispute shall be resolved by the surveyor on behalf of the lessor and the
     surveyor on behalf of the lessee (each party shall bear the costs and fee
     of its surveyor); and in accordance with the ruling on the disagreement a
     new notification (according to section 6) shall be issued by the lessor. As
     long as the dispute has not been resolved, the original notice by the
     lessor under section 6 above shall continue to apply.

8.   This special appendix is an integral part of the tenancy agreement.

IN WITNESS WHEREOF THE PARTIES HAVE AFFIXED THEIR SIGNATURES

TODAY, 13 DECEMBER 1999, IN JERUSALEM

[company stamp:                            [signature:]
Har Hotzvim Properties, Ltd.]
[signatures:  ?? & ??]

            LESSOR                                    LESSEE
<PAGE>

                                  APPENDIX A-1

[captions]

Building A                   Building C                     Building D

                             Building B

Boundary                                                          Boundary
of the lot                                                        of the lot
<PAGE>

                          APPENDIX A-2 [ADDED BY HAND]

[captions]

                   Area 368 sq. m.           Area 353 sq. m.

                   Area 400.2 sq. m.         Area 406 sq. m.
<PAGE>

                                                             Our reference: 2050
                                                                      Appendix B

                                  TENANT AREAS

1.   FLOOR:

     o    Finish:  smooth concrete

     o    Height of industrial story about 4.60 meters (from concrete floor to
          concrete ceiling). Not relevant for Emultek

     o    Height of office story about 3.60 meters (from concrete floor to
          concrete ceiling)

     o    Maximum load capacity of floor - 630 kg/square meter

2.   SHELL WALLS:

     o    Outside walls of concrete block and/or curtain walls, ready for
          plastering by lessee

     o    Outside walls finished in dressed stone and/or aluminum, depending on
          architect's plans

3.   CENTRAL AIR-CONDITIONING UNIT:

     o    air-conditioning system for entire building based on chilled water
          unit with air condenser

     o    Chilled water supplied to coilpipe bellows units and air treatment
          units

     o    Boiler room--heating energy center will provide hot water to heat the
          system

     o    Four-pipe air-conditioning system--two pipes for cold water and two
          pipes for hot water

     o    All air-conditioning installations in the leased premises (planning
          and implementation) will be handled by the Tenant and will include
          connection to the cold and hot water lines located in the public
          central shaft.

     o    The plans must be approved by the lessor before the start of work.

     o    The lessee will have the air-conditioning work done by Calorit Ltd.

     o    Clean air for the coilpipe bellows units will be provided to the
          Tenant from the existing conduit in the floor shaft.

     o    Exhaust from lavatories--the Tenant will hook up to the existing
          ventilation conduit in the central shaft.
<PAGE>

4.   PLUMBING AND SPRINKLER SYSTEM:

     o    All sanitary systems will rely on gravity flow except for the floor of
          the lower basement.

     o    Infrastructure for vertical wastewater pipes exists alongside some of
          the pillars in the leased premises areas on each floor, as marked in
          the blueprints.

     o    There are also sumps (at locations marked on the sketch) for
          air-conditioning drainage.

     o    The water supply system is based on the municipal system.

     o    There are water lines on each floor in the public shafts. The lessee
          will hook up to these lines.

     o    There are water reservoirs in the central shafts for the sprinklers
          and hydrants only--hook-up by the lessee.

     o    The main water lines are alongside the central shafts with
          infrastructure for water meters--hook-up by the lessee.

     o    The lessee will be responsible for having the plumbing and sprinkler
          system work done by Calorit Ltd.

     o    Sprinklers--the main line for the sprinklers is in the central shaft;
          the lessee will hook up to this line.

5.   ELECTRICITY:

     o    The electrical system is based on the Electric Company's network of
          distribution cables throughout the building. On each floor, in the
          central core, there is a cabinet of the appropriate size for
          installing electric meters for the tenants. Hook-up by the lessee.

     o    Every lessee will have its own hook-up to the Electric Company and
          will sign a contract with the Electric Company and have a meter
          installed.

     o    The capacity of the hook-up allocated to the lessee is 0.25 amperes
          per square meter; if the lessee wishes to increase this it must bear
          the added expense.

     o    The lessee will have the electrical work in the leased premises
          performed by Sharon Ltd. The work for which the lessee is responsible
          will include, inter alia, the connection as far as the meter that will
          be installed in the central shaft.

6.   MISCELLANEOUS:

     a.   All plans must be approved by the lessor before the start of work.

     b.   The facades of leased premises that face public areas must be approved
          by the architect.

     c.   Plans for the internal division of space drawn up by the lessee must
          meet the demands of standards, including safety standards.
<PAGE>

                                          Appendix B (continued) [added by hand]

       Work to be performed by the lessor in the office area of the lessee
                                [added by hand]

                  TECHNICAL SPECIFICATION FOR THE TENANT'S AREA

We shall make the following modifications to the leased premises.

a.   Floor:  fire-resistant carpeting at a base price of $12 per square meter

b.   Rando Fisher 6 x 60 acoustic ceiling--base price, $4 per square meter

c.   Plaster walls including 2" insulation

d.   Decorel doors with honeycomb fill and Fournir veneer--up to 20 units

e.   Walls--Superacril white paint

f.   Lavatories--minimum standard

g.   Kitchenette--three meters long, with marble countertop and sink

h.   Installation of sprinkler system

i.   Electricity - 2 x 36 W parabolic lighting fixtures
     3 x 160A main electric panel
     50 electric outlets and infrastructure for 25 computer/telephone outlets

j.   air-conditioning--hook up to central system in accordance with plans as
     provided by the air-conditioning consultant for the building
<PAGE>

                                          Appendix B (continued) [added by hand]

              TECHNICAL SPECIFICATION FOR BUILDING B - PUBLIC AREAS

1.   STAIRWELLS:

     o    Marble flooring

     o    Stone and plaster walls

2.   FOYER ON FLOOR:

     o    Marble flooring and wall paneling

     o    Metal and/or wood cabinets

     o    Mineral and/or metal acoustic ceilings, including recesses, and
          fluorescent lighting

3.   FLOOR DIMENSIONS:

     o    Terrazzo tile flooring

     o    Walls and ceiling--Tambourtex and/or Polycid paint

4.   CENTRAL SHAFTS:

     o    Intended to carry systems (air-conditioning, sprinkler system,
          plumbing, electricity, and telecommunications). The lessee will lay
          the systems of the leased premises as far as the shaft. The work will
          be planned and carried out in coordination with and after approval by
          the lessor.

5.   ROOFS AND BALCONIES:

     o    Waterproofing including thermal insulation

     o    Balconies with stone and/or marble paving

6.   OUTSIDE SHELL:

     o    Combination of concrete walls including dressed stone facing and
          thermal insulation with a total thickness of about 30 cm and glass and
          aluminum curtain walls according to architect's plans

7.   PARKING FACILITIES:

     o    Smooth concrete floor

     o    Full parking facility illumination

     o    Fire extinguisher and hydrant system in accordance with safety
          requirements
<PAGE>

8.   DEVELOPMENT:

     o    Asphalt pavement combined with another material such as tiled stones

     o    Central trash facility

     o    Outside lighting in accordance with specifications of electrical
          consultant

     o    Loading and unloading bays on first and second stories (Building B
          only)

9.   CENTRAL ENERGY SYSTEMS:

     o    There is infrastructure in shafts for the lessee to hook up to the
          public systems (hook up to main sprinkler system, air-conditioning and
          heating lines)

     o    Central air-conditioning system (chillers) on roof of structure

     o    Emergency generator to backup public grid

     o    Central monitoring system to control public facilities

10.  ELEVATORS:

     o    Two elevators in each core--passenger elevator and dual use
          (passenger/freight) elevator

     o    Elevator cabin finished as determined by architect
<PAGE>

                   SPECIMEN [superimposed on document by hand]

                                                      Appendix D [added by hand]
                                                     Promissory note No. _______

                          INDEX-LINKED PROMISSORY NOTE

             Executed on the _____day of the month of _____, 199__.

1.   On the 01 day of the month of July, in the year 2000, we promise to pay to
     the order of Har Hotzvim Properties Ltd. (hereinafter "Har Hotzvim
     Properties"), corporation No. 51-168405-2, of 27 Hamered St. Tel Aviv, the
     sum of 64,449 new sheqels (sixty-four thousand four hundred forty-nine
     sheqels), linked (hereinafter together--"the amount"), as detailed below:

2.   The amount shall be linked to the Consumer Price Index (including fruits
     and vegetables) published from time to time by the Central Bureau of
     Statistics and Economic Research. The "base index" for this note is 106.8
     index for 10/99 and the "determining index" is the index that will be known
     on the actual day of payment of the note.

3.   If on the day of payment of this note the (new) determining index is higher
     than the base index, we shall pay Har Hotzvim Properties the amount of the
     note augmented proportionally to the rise in the "new" determining index as
     against the base index (hereinafter "linkage differentials"). To avoid all
     doubt it is hereby made clear that in any case the amount will not be
     reduced in the event that the "new" determining index is lower than the
     base index.

4.   If on the day of payment of this note there exists an obligation to pay
     Value Added Tax at its legal rate, the amount as defined in section I of
     this note above shall be supplemented by an additional amount on account of
     the Value Added Tax, plus linkage differentials on its account as well. In
     order to avoid all doubt we agree and affirm that the amount of Value Added
     Tax will be levied on the amount including the supplement on account of
     linkage differentials.

5.   We exempt the holder(s) of this note from any obligation of presentation
     and/or dispatch of and warnings or notices whatsoever.

                                Place of payment:

Bank:  10 Leumi                           Branch:  913 Mahane Yehuda
account 121600/19

                      Signatures of Executors of the Note:

Name:  BRT Biopharmaceuticals Ltd.        Name:
ID number:  51-285095-9                   ID number:
Address:  216 Jaffa Road, Jerusalem       Address:
             name and place address                 name and place address
Workplace:                                Workplace:
X Signature                               X Signature

We the undersigned guarantee, individually and collectively, the payment of this
note by the signatories. This guarantee shall not be affected adversely by the
grant of an extension or discounts to the signatories and/or to any guarantor
and/or to any endorser of this note. We individually and collectively hereby
waive any right to assert a claim of expiration or any other claim in connection
with this note, inter alia under the provisions of the Notes Ordinance and in
addition we hereby exempt the holder(s) of this note from any need to present
and/or send any warnings or notices whatsoever.

                            Signatures of Guarantors:

Name:                                     Name:
ID number:                                ID number:
Address:                                  Address:
             name and place address                 name and place address
Workplace:                                Workplace:
X Signature                               X Signature
<PAGE>

Name:  BRT
Address:

                        [stamp: Bank Leumi Le-Israel Ltd.
                   Business Branch - Mahane Yehuda, Jerusalem
                                   15-12-1999
                                913 RECEIVED 913]

To:
Bank Leumi le-Israel Ltd.
Branch:  Mahane Yehuda

                                                                   Date 15/12/99

                        Re: REQUEST TO ISSUE A GUARANTEE

Please issue a guarantee/obligation (hereinafter "the guarantee") in accordance
with the following form and details:

1.   Name of beneficiary: Har Hotzvim Properties Ltd. (indicate the name of the
     person or corporation that will be the beneficiary of the guarantee)

2.   Address of the beneficiary

3.   Amount of the guarantee:  122,000--

4.   Name of maker: BRT Biopharmaceuticals Ltd. (indicate the name of the person
     or corporation on whose behalf the guarantee will be issued)

5.   With reference to:  compliance with a tenancy contract

6.   Validity of the guarantee: 31/3/2001 (indicate the date to be inscribed on
     the guarantee as the last date for reception of the demand by the bank)

7.   Indexation terms:  Consumer Price Index 10/99

8.   Remarks:

The commission for the guarantee shall be at the rate of 2.6% per annum of the
amount of the guarantee (including interest, indexation differentials, or
exchange-rate differentials, if any) but in no case less than the sum of NIS
___*.

Please debit thereupon our account with you number 121600/19.

In addition, we are aware that we will be charged a commission for drafting
documents in the amount of NIS 350.

What is stated in the obligation we have signed for you with relation to the
issuance of the guarantee and/or indemnity by you shall also apply to the above
the guarantee (and to extensions of its validity if any).

*minimum commission as this appears in the list of commissions.

[company stamp:  Har Hotzvim Properties, Ltd.]    [signature} IRA WEINSTEIN
                                                  [company stamp:  BRT
                                                      Biopharmaceuticals Ltd.]

                                                         Customer's Signature

--------------------------------------------------------------------------------
For use by the branch

Guarantee No.     File No. _____

Total obligo in guarantees _______  Approval by branch management ________

Securities offered ________         Approval by district management, dated _____

Remember that the customer must sign (on the copy of the guarantee that remains
in the branch) the guarantee document.
<PAGE>

                          BRT BIOPHARMACEUTICALS, LTD.
               216 JAFFA ROAD, SHA'AREI HA'IR - JERUSALEM - 94383
                    Phone: 972-2-5374997 - Fax: 972-2-5375098

[stamp:  Bank Leumi Le-Israel Ltd.
Business Branch - Mahane Yehuda, Jerusalem
15-12-1999
913 RECEIVED 913]

14 December 1999

To:
Bank Leumi
Mahane Yehuda Branch
Jerusalem

Dear Sirs and Mesdames,
               Re:  promissory notes to the order of Har Hotzvim Properties Ltd.

Enclosed please find a list of the promissory notes that we have conveyed to the
Har Hotzvim Co., Ltd., on account of a tenancy agreement. We hereby give you an
irrevocable instruction to honor these notes on the date fixed for their payment
and to pay them from our account number 121600/19 maintained at your branch.

Sincerely,

[signature] Ira Weinstein
[signature] Moshe Laster
<PAGE>

                          BRT BIOPHARMACEUTICALS, LTD.
               216 JAFFA ROAD, SHA'AREI HA'IR - JERUSALEM - 94383
                    Phone: 972-2-5374997 - Fax: 972-2-5375098

Promissory notes to be honored:

NUMBER             DATE                          AMOUNT (INDEX LINKED)
1                  1 October 2000                     NIS 66,141
2                  1 January 2001                     NIS 66,141
3                  1 April 2001                       NIS 66,141
4                  1 July 2001                        NIS 66,141
5                  1 October 2001                     NIS 66,141
6                  1 January 2002                     NIS 66,141
7                  1 April 2002                       NIS 66,141
8                  1 July 2002                        NIS 66,141
9                  1 October 2002                     NIS 66,141
10                 1 January 2003                     NIS 66,141
11                 1 April 2003                       NIS 66,141
12                 1 July 2003                        NIS 66,141
13                 1 October 2003                     NIS 66,141
14                 1 January 2004                     NIS 44,094
<PAGE>

                         APPENDIX E TO TENANCY AGREEMENT

Between: Har Hotzvim Properties Ltd. ("the lessor")

And:     BRT Biopharmaceuticals Ltd. ("the lessee")

                                    INSURANCE

1.   This appendix constitutes an integral part of the tenancy agreement between
     the lessor and the lessee that was signed with regard to the leased
     premises that are unit No. B/3/101 in Building B in the Ramot Meir project,
     Har Hotzvim, Jerusalem.

2.   The lessee undertakes to take out and maintain the insurance detailed in
     the provisions of this appendix and undertakes to abide by all of the
     obligations imposed on it by the various provisions of this appendix, and
     as follows:

     2.1  Before the date of the handover of possession of the leased premises
          and/or before the date of the granting of permission and as a
          condition for receiving permission to carry out work in the leased
          premises and/or before the starting date of any work whatsoever in the
          leased premises by the lessee and/or on its behalf and/or for its
          benefit--whichever of these three may be earliest--the lessee
          undertakes to take out and maintain "construction work insurance" as
          enumerated in Appendix E-1 (attached to the present Appendix E as part
          thereof) at its own expense with a legally certified insurance company
          that has a reputation in Israel, concerning all work to be performed
          by it and/or on its behalf and/or for its benefit in the leased
          premises, including equipment, systems, and machines that will be used
          for the lessee's business as well as repairs, renovations,
          improvements, modifications, and additions that may be made to the
          leased premises.

     2.2  Without a need for any request or application by the lessor and/or the
          management company, the lessee undertakes to convey to the lessor no
          later than the date of the handover of possession of the leased
          premises or the date of the start of any work whatsoever in the leased
          premises, whichever of these two may be earlier, confirmation that it
          has taken out construction insurance, on the model of the
          "construction insurance certification" attached to the present
          appendix and labeled Appendix E-1, signed in due legal form by the
          insurer. The lessee and the lessor and/or the management company shall
          be entitled to prevent the lessee from carrying out work in the leased
          premises and/or handling over possession of the leased premises in the
          event that the said confirmation has not been presented before the
          said date.

     2.3  Without detracting from the liability and obligations of the lessee
          under this tenancy agreement and the present Appendix E and under the
          management contract and/or according to law, from the date of the
          introduction of any property and/or belongings whatsoever to the
          leased premises or from the date of the start of the term of the
<PAGE>

          lease and/or from the date of the handover of possession of the leased
          premises (whichever is earliest), the lessee undertakes to purchase at
          its own expense and to maintain throughout the entire period of the
          lease the insurance detailed in the "certification of tenant
          insurance" attached to the present Appendix E as part thereof and
          designated Appendix E-2 (hereinafter "tenant insurance").

     2.4  The lessee undertakes to update the amount of the coverage on account
          of the insurance stated in the "certification of tenant insurance"
          from time to time so that it always reflects the full value, at
          replacement value, of the property insured thereunder.

     2.5  Without a need for any request or application by the lessor and/or the
          management company, the lessee undertakes to convey to the lessor
          and/or the management company, no later than the date of the start of
          the lease or the date of the introduction of any property whatsoever
          to the leased premises, whichever of these two may be earlier,
          confirmation that it has taken out insurance on the leased premises on
          the model of the "certification of tenant insurance" attached to the
          present appendix and labeled Appendix E-2, signed in due legal form by
          the insurer. The lessee states that it is aware that presentation of
          the said "certification of tenant insurance" is a necessary and
          prerequisite condition for the start of any activity by the lessee in
          the leased premises and/or the introduction of any property whatsoever
          to the leased premises as stated above, and the lessor and/or the
          management company shall be entitled to prevent the lessee from
          conducting any activity in the leased premises and/or introducing any
          property as stated in the case that the said certification is not
          submitted to it before the date stipulated above.

     2.6  To avoid any misunderstanding it is made clear that the failure to
          present the above certifications of insurance and insurance policies
          on the date stated above shall not detract from the obligations of the
          lessee under the tenancy agreement, including, and without detracting
          from the generality of what is stated, the execution of any payment
          that devolves on the lessee, and the lessee undertakes to meet all of
          its obligations under the tenancy agreement and management contract
          even if it is prevented from carrying out work and/or receiving
          possession of the leased premises and/or introducing property to the
          leased premises and/or opening its business in the leased premises,
          because of the failure to present the certifications on time.

     2.7  In this context it is made clear that nothing in the taking out of the
          above insurance by the lessee can limit or detract in any fashion
          whatsoever from the lessee's obligation under the tenancy agreement
          and management contract and shall not release it from its obligation
          to compensate the lessor and/or the management company or any person
          whatsoever on account of any damage for which the lessee is liable
          under the tenancy agreement and under the management contract and/or
          by law.

     2.8  The payment of any insurance benefits whatsoever shall have no force
          other than reduce the amount of indemnification or compensation to
          which the lessor and/or the management company may be entitled on
          account of damage or loss.
<PAGE>

     2.9  No later than 14 days before the expiration of the term of the tenant
          insurance, the lessee undertakes to deposit with the lessor and/or the
          management company certification of tenant insurance as stated in
          section 2.5 above on account of the extension of its validity for
          another year.

     2.10 The lessor and/or the management company shall be entitled to examine
          the insurance certificates presented by the lessee as stated above and
          the lessee undertakes to make any change or modification that may be
          required in order to make them compatible with its obligations. The
          lessee declares and undertakes that the rights of the lessor and/or
          the management company to conduct this examination and demand changes
          as stated about do not impose upon the lessor and/or the management
          company or anyone on their behalf any duty or any responsibility
          whatsoever concerning the stated insurance certificates, their nature,
          their scope, and their term of validity, or concerning their absence,
          and nothing in them can detract from any obligation imposed on the
          lessee under the tenancy agreement and the management contract, and
          this whether or not they so requested and whether or not they so
          examined.

     2.11 The lessee undertakes to abide by all conditions of the policies
          mentioned above in the present appendix, to pay the premiums in full
          and on time, and to see to it and to verify that the leased premises
          and tenant insurance policies are renewed from time to time, as
          required, and remain in force throughout the term of the lease.

          Should the lessee fail to meet its obligations under this entire
          appendix, the lessor and/or the management company shall be entitled,
          but not required, to take out the insurance or some portion thereof in
          the place of the lessee and at its expense and/or to pay in its place
          any sum whatsoever, and this without detracting from the right of the
          lessor and/or the management company to any other remedy.

     2.12 The lessee undertakes not to perform and/or allow anyone acting on its
          behalf to commit any act of commission or omission that may tend to
          increase the insurance outlays of the lessor and or the management
          company and/or other lessees on account of insurance of the structure
          or its leased premises.

          The lessee undertakes that to the extent that the lessor and/or the
          management company may be required to make other insurance payments
          beyond the norm on account of activity by the lessee, the lessee shall
          pay to the lessor and/or to the management company, as appropriate,
          the stated supplement immediately upon receipt of the first request to
          do so.

3.   The lessor and/or the management company shall take out the following
     insurance (hereinafter "Company insurance"):

     3.1  Extended fire insurance for the structures of the project. For the
          purposes of this section, the "structures of the project" do not
          include the contents of the tenant's unit and/or any addition, repair,
          modification, renovation, or expansion made to the tenant's unit by
          the lessee or someone acting on its behalf. This insurance shall
<PAGE>

          include a waiver of the right of subrogation vis-a-vis the lessee,
          except in the case of damage caused by the lessee or by anyone acting
          on its behalf with malicious intent ("the tenant's unit" means "the
          leased premises").

     3.2  Insurance against the loss of rent at its full value on account of
          damage that may be caused to the leased premises and/or the project as
          a result of risks that are covered by the property insurance
          enumerated in section 3.1 above. This insurance shall include a waiver
          of the right of subrogation vis-a-vis the lessee, except in the case
          of damage caused by the lessee or by anyone acting on its behalf with
          malicious intent.

     3.3  Third-party liability insurance against bodily damage and/or property
          damage that may be caused outside the area of the units and leased
          premises and that is related to the operation, maintenance, and
          management of the public areas of the project. The insurance shall be
          extended to indemnify the lessee in the event that it is adjudged to
          be responsible for the acts of commission and/or omission of the
          lessor or management company and shall include a cross-liability
          clause.

          This insurance does not cover the separate and unique liability of the
          lessee for damages associated with the leased premises themselves
          and/or associated with the lessee and/or the content of the leased
          premises.

     3.4  Employers' liability insurance to cover liability of the lessor and/or
          the management company vis-a-vis their employees under any law. This
          insurance shall be extended to indemnify the lessee in the event that
          it is adjudged to be the employer of any of the employees of the
          management company and/or the lessor.

     3.5  Additional insurance at the discretion of the lessor and/or at the
          discretion of the management company.

Copies of the "company insurance" policies shall be on file in the offices of
the management company and available for examination by tenants during regular
working hours.

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]

              LESSOR                                       LESSEE
<PAGE>

                                  APPENDIX E-1
          (SUBSIDIARY APPENDIX TO APPENDIX E TO THE TENANCY AGREEMENT)

Between: Har Hotzvim Properties Ltd. ("the lessor")

And:     BRT Biopharmaceuticals Ltd. ("the lessee")

                     Certification of Construction Insurance

To:
Har Hotzvim properties Ltd. (hereinafter "the lessor")
____________________(hereinafter "the management company")
____________________

Dear Sirs or Mesdames

        Re: CERTIFICATION OF THE ISSUANCE OF CONSTRUCTION WORK INSURANCE

We hereby certify that starting on 1 January 2000 and continuing until 31 March
2000 we have drawn up on behalf of BRT Biopharmaceuticals Ltd. (hereinafter "the
lessee") and in its name the insurance listed below and in accordance with what
is stated in section 11 and Appendix E of the tenancy agreement between you
(unit ____ in Building ___ in the Ramot Meir project, Har Hotzvim, Jerusalem),
as follows:

1.   CONSTRUCTION INSURANCE--policy to insure work by contractors--all risks
     [added by hand:]
            not including break-ins

CHAPTER 1 - PROPERTY INSURANCE

The policy covers the work, including materials, equipment, installations, and
everything else that may be brought to carry out the work of any type whatsoever
on the property leased under the aforesaid tenancy agreement.

This insurance includes the lessor and the management company and their
employees and or executives and all the contractors and subcontractors as
additional beneficiaries.

Total value of the work:  $120,000

This policy includes the following extensions:   Removal of rubble in the amount
                                                 of $12,000

                                                 Adjacent property and property
                                                 being worked on in the amount
                                                 of $250,000
<PAGE>

CHAPTER 2 - THIRD-PARTY LIABILITY INSURANCE

This policy will cover liability of the insured vis-a-vis any third party on
account of any injury whatsoever, loss, or damage to body and/or property as a
result of the work specified in chapter 1 above. This insurance shall include
the lessor and the management company and their executives and their employees
and all contractors and subcontractors as additional insured parties.

The liability limits of this policy are NIS 500,000 per incident and for the
entire term.

The policy includes the following extensions:    Cross-liability clause

                                                 Property belonging to the
                                                 lessor and/or the management
                                                 company shall be considered to
                                                 be third party

                                                 Any person who is not included
                                                 in the wage lists of the
                                                 insured party shall be
                                                 considered to be a third party.

                                                 Damage to third-party property
                                                 as a result of the use of motor
                                                 vehicles, excluding liability
                                                 that is indemnifiable under the
                                                 Law for Compensation of Traffic
                                                 Accident Victims and liability
                                                 covered by a standard
                                                 motor-vehicle insurance policy.
                                                 The liability beyond the above
                                                 is within the limits of
                                                 liability specified above.

CHAPTER 3 - EMPLOYERS' LIABILITY INSURANCE

This policy will cover the liability under the law of each of those insured
vis-a-vis its employees, representatives, and any other person found in its
service and subject to its authority, including subcontractors, their employees,
their representatives, and any other person in their service and/or subject to
their authority, on account of bodily, mental, or emotional damage or death that
may be caused to each of those enumerated above in connection with his or her
work.

[added by hand:] $1,500,000 per employee and per incident.

The liability limits of this insurance are $5,000,000 (five million United
States dollars) per claimant and for the entire term.

This policy includes the lessor and the management company and all contractors
and subcontractors as additional insured parties.

In addition, this policy is not subject to any restriction with regard to
working hours, contractors, subcontractors, their employees, their
representatives, or any other person found in their service and/or subject to
their authority, work on heights or in depths, lures and poisons, as well as the
employment of youth.
<PAGE>

2.   MISCELLANEOUS

     2.1  We affirm that the aforesaid policy (or policies), chapters 1, 2, and
          3, that are enumerated above, include an explicit clause with regard
          to the waiver of the right of subrogation vis-a-vis the lessor, the
          management company, their executives and/or employees, any person in
          their service, and vis-a-vis other lessees in the aforesaid project
          and/or their employees and executives of all of the above and all
          those acting on their behalf.

     2.2  We hereby undertake not to cancel and not to modify and not to reduce
          the above insurance policies or any of them without providing previous
          written notice by registered mail of at least 30 days to the lessor
          and/or to the management company.

     2.3  We affirm that the lessor and/or the management company shall not be
          liable for payment of premiums for the policies mentioned above and
          for fulfilling all of the obligations imposed upon the insured under
          the terms of the policy.

     2.4  The insurance under the above policy (or policies) (chapters 1, 2, and
          3 above) is primary insurance and takes precedence over any other
          insurance taken out by the lessor and/or by the management company.

[company stamp] Zion Insurance Company      [signature]
                seal of the insurer                   Signature of the insured
[signature]                                 underwriter
                Name of signatory                     position of the signatory
Ben Yehuda 1, Jerusalem
              Address of the insurer
02 623 4341
           telephone number of the insurer

               SIGNATURES FOR THE PURPOSE OF THE TENANCY AGREEMENT

--------------------------------------------------------------------------------
                                   [company stamp:  BRT Biopharmaceuticals Ltd.]
                                   [Signatures:  Moshe Laster & Ira Weinstein]
--------------------------------------------------------------------------------
         "The Lessor"                              "The Lessee"
--------------------------------------------------------------------------------
<PAGE>

                                  APPENDIX E-2
          (SUBSIDIARY APPENDIX TO APPENDIX E TO THE TENANCY AGREEMENT)

Between: HAR HOTZVIM PROPERTIES LTD. ("THE LESSOR")

And:     BRT BIOPHARMACEUTICALS LTD. ("THE LESSEE")

                        CERTIFICATION OF TENANT INSURANCE

To:
Har Hotzvim properties Ltd. (hereinafter "the lessor")
____________________(hereinafter "the management company")
____________________

Dear Sirs or Mesdames

  Re: CERTIFICATION OF THE ISSUANCE OF EMPLOYERS' LIABILITY INSURANCE, THIRD-
      PARTY LIABILITY INSURANCE, PROPERTY INSURANCE, AND LOSS OF PROFIT
      INSURANCE

We hereby certify that we have issued the policies enumerated below, as stated
in section 11 and Appendix E of the tenancy agreement between the lessor and BRT
Biopharmaceuticals Ltd. (hereinafter "the lessee") on account of the property
leased by the lessee in the Ramot Meir project, Building B, unit ____, Har
Hotzvim, Jerusalem, and this for the period beginning on 31 January 2000 and
concluding on 31 December 2000.

1.   THE INSURANCE

Chapter 1.  Coverage of the lessee's liability vis-a-vis its workers and/or all
            those employed by it or on its behalf under the Torts Ordinance (new
            version) and/or the Defective Products Liability Law 5740-1980, on
            account of death and/or bodily damage to any worker as a result of
            accident or illness during the course of or as a result account of
            his or her employment, with a liability limit in the amount of
            5,000,000 (five million United States dollars) and the total for the
            entire period of the annual insurance. [added by hand:] per incident
            and worker $1,500,000.

            This policy has been extended to indemnify the lessor and/or the
            management company to the extent that they may be adjudged to be the
            employers of the workers of the lessee and its employees or any of
            them.

Chapter 2.  Third-party liability insurance--coverage of the lessee's liability
            vis-a-vis the lessor and/or vis-a-vis the management company and/or
            vis-a-vis any third party, under the laws of the State of Israel
            with a limit of liability that is not less than a sum in sheqels
            equal to NIS 500,000 for a single case and the total for the entire
            period of the annual insurance.

            The said policy is not subject to any limitation with regard to
            liability that may stem from fire, panic, explosion, lifting
            equipment, loading and unloading,
<PAGE>

            poisoning, any harmful item in food and drink, defective sanitary
            installations, strike and lockout, or claims on behalf of the
            National Insurance Institute.

Chapter 3a. Property insurance--Coverage for the content of the leased premises
            and any other property in the ownership and/or responsibility of the
            lessee including any repair, modification, improvement, renovation,
            or addition to the leased premises that has been performed and/or
            may be performed by the lessee and/or those acting on its behalf at
            the replacement value, against the risks of fire, smoke, lightning,
            explosion, earthquake, storm, tempest, flood, damage by liquids,
            impact by aircraft, sonic boom, collision, strikes, riots, malicious
            damage, and break-in.

            The name of the insured party includes also the lessor and the
            management company.

Chapter 3b. Insurance against loss of profits by the lessee has result of damage
            caused to the leased premises and/or to its contents as a result of
            the risks insured as stated above, for a period of indemnification
            that is not less than 12 months.

2.   MISCELLANEOUS

     2.1  We affirm that the aforesaid policy (or policies), chapters 1, 2, 3a,
          and 3b, that are enumerated above, include an explicit clause with
          regard to the waiver of the right of subrogation vis-a-vis the lessor,
          the management company, their executives and/or employees, any person
          in their service, and vis-a-vis other lessees in the aforesaid project
          and/or their employees and executives of all of the above and all
          those acting on their behalf.

     2.2  We hereby undertake not to cancel and not to modify and not to reduce
          the above insurance policies or any of them without providing previous
          written notice by registered mail of at least 30 days to the lessor
          and/or to the management company.

     2.3  We affirm that the lessor and/or the management company shall not be
          liable for payment or premiums for the policies mentioned above and
          for fulfilling all of the obligations imposed upon the insured under
          the terms of the policy.

     2.4  The insurance under the above policy (or policies) (chapters 1, 2, and
          3a and 3b above) is primary insurance and takes precedence over any
          other insurance taken out by the lessor and/or by the management
          company.

[company stamp] Zion Insurance Company           [signature]
                seal of the insurer                    Signature of the insured
[signature]                                      underwriter
                Name of signatory                      position of the signatory
Ben Yehuda 1, Jerusalem
            Address of the insurer
02 623 4341
         telephone number of the insurer
<PAGE>

               Signatures for the Purpose of the Tenancy Agreement
--------------------------------------------------------------------------------
                                  [company stamp:  BRT Biopharmaceuticals Ltd.]
                                  [Signatures:  Moshe Laster & Ira Weinstein]
--------------------------------------------------------------------------------
            "The Lessor"                       "The Lessee"
--------------------------------------------------------------------------------

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