Sublease

Sublease


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                                                                  EXHIBIT 10.2




                                    SUBLEASE

         THIS SUBLEASE is made as of this 2nd day of August, 1995, by and
between ONCOGENE SCIENCE, INC., a Delaware corporation (successor to Applied
bioTechnology Inc., formerly named AbT Acquisition Corp.) having an office at
80 Rogers Street, Cambridge, Massachusetts 02142 ("Sublessor"), and
CALBIOCHEM-NOVABIOCHEM CORPORATION, a California corporation having an office
at 10394 Pacific Center Court, San Diego, California 92121 ("Sublessee").

                              W I T N E S S E T H:

         WHEREAS, by lease, dated as of October 1991, between the Trustees of
the East Cambridge Trust ("Landlord"), as landlord, and AbT Acquisition Corp.,
predecessor in interest to Sublessor, as tenant (said lease, as the same has
been amended by First Amendment dated as of April 2, 1993 and by Second
Amendment executed in connection with the execution and delivery of this
Sublease, and as the same may be hereafter amended from time to time, being
referred to herein as the "Lease"), Landlord leased to Sublessor the buildings
known as 80 Rogers Street and 129 Binney Street and a portion of the building
known as 84 Rogers Street, Cambridge, Massachusetts (the "Leased Premises");
and

         WHEREAS, Sublessor desires to sublet to Sublessee and Sublessee
desires to sublet and hire from Sublessor that portion of the Leased Premises
located at 80 and 84 Rogers Street more particularly shown on the floor plan
attached hereto and made a part hereof as Exhibit A (the "Sublet Premises") and
all of Sublessor's right, title and interest therein and/or appurtenant
thereto, all on the terms, covenants and conditions set forth herein;

         NOW, THEREFORE, the Sublessor and Sublessee hereby agree to the
foregoing and as follows:

         1.        Term.

                   a.        Sublessor hereby leases to Sublessee and Sublessee
hereby leases and hires from Sublessor the Sublet Premises upon and subject to
all of
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the terms, covenants and conditions provided for in this Sublease.  The term of
this Sublease shall commence on the date hereof (the "Commencement Date"), and,
subject to Section 1(b) below, shall expire on the date which is one day prior
to the third anniversary of the Commencement Date (the "Expiration Date"),
unless such term shall expire, be cancelled or terminate on an earlier date
pursuant to the terms of this Sublease or the Lease, in which event such
earlier date shall be deemed to be the Expiration Date.  The period from and
including the Commencement Date to and including the Expiration Date is herein
called the "Term."

                   b.        Sublessee shall have the option to extend the Term
of this Sublease for one year from the scheduled Expiration Date, and
thereafter to further extend the Term of this Sublease for additional periods
of one year each (except that in no event shall any such extension period
extend beyond the day before the expiration of the term of the Lease), provided
that in connection with each such extension: (i) Sublessee shall have given
Sublessor not less than nine (9) months' prior written notice thereof; (ii)
this Sublease shall not have been previously terminated; and (iii) at the time
of its giving of such notice and on the Expiration Date of the then current
Term, no default under this Sublease by Sublessee shall have occurred and be
continuing beyond all applicable notice and cure periods.  Any renewal option
may be exercised with respect to the entire Sublet Premises only.

         2.        Rent.

                   a.        Sublessee shall pay to Sublessor annual rent
(hereinafter "Fixed Rent") in amounts equal to 50% of the aggregate Annual
Fixed Rent described in Section 1 of the Lease (including, without limitation,
the CPI increases described therein).

                   b.        All Fixed Rent shall be paid in lawful money of 
the United





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States at the office of Sublessor set forth above, or at such other place as
Sublessor may designate in writing, without any notice, demand, set-off or
deduction whatsoever, and shall be payable in advance on the first day of each
and every month during the Term.  Sublessee shall pay the first monthly
installment of Fixed Rent in full upon the execution hereof.

                   c.        If the Commencement Date is on other than the
first day of a calendar month, the second installment of Fixed Rent shall be
adjusted appropriately to reflect payment of Fixed Rent for the number of days
then remaining in said first month from and including the Commencement Date.

                   d.        In addition to Fixed Rent, Sublessee shall pay to
Sublessor as additional rent, Sublessee's Proportionate Share (as defined
herein) of the amounts payable by Sublessor in respect of "Real Estate Taxes"
and "Operating Expenses" pursuant to Section 6.2 of the Lease on account of
periods occurring during the Term.  "Sublessee's Proportionate Share" shall
mean fifty (50%) percent or, if the Leased Premises are increased or decreased,
the percentage equal to a fraction, the numerator of which is 50% of the
rentable square feet of the Leased Premises as the same are presently
constituted and the denominator of which is the then number of square feet of
rentable area of the Leased Premises as the same may be constituted following
such increase or decrease.

                   e.        Upon receipt by Sublessor of any refund,
adjustment or credit attributable to escalations under Section 6.2 of the
Lease, Sublessee shall be entitled to receive from Sublessor Sublessee's
Proportionate Share of such refund, adjustment or credit, based on the portion
of, and in no event to exceed, such escalations attributable to any payment
made by Sublessee under this Article, but net of Sublessor's reasonable,
out-of-pocket expenses, if any, incurred in obtaining the same.

                   f.        Sublessee shall pay to Sublessor 50% of the 
expenses





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incurred by Sublessor with respect to the following items relating to the
Leased Premises: (i) property management; (ii) electricity; (iii) gas; (iv)
facility maintenance; (v) trash removal; (vi) office cleaning and laundry;
(vii) water and sewer charges; (viii) security/fire system; (ix) pest control;
(x) building permits; and (xi) amortization of leasehold improvements;
provided, however, that with respect to each such item, such 50% shall be
subject to periodic review and equitable adjustment based on the then current
utilization of such item by each of the parties.  Each party shall have the
right to install, at its own cost and expense, one or more meters to segregate
the measurement of that party's utilities usage and pay the charges incurred in
connection therewith directly to the utility provider and remove the cost
thereof from the list of shared expenses set forth above.  It is understood and
agreed that Sublessor has no control over the supply of electrical energy or
the quality, quantity or character of electrical energy supplied to the Sublet
Premises.  Unless caused by the negligence or willful misconduct of Sublessor
(or any party for whom Sublessor is legally responsible), Sublessor shall not
be liable or responsible to Sublessee for any loss, damage or expense that
Sublessee may sustain or incur due to any diminution or abatement in the
quantity of electrical energy or any change in the quality or character of such
electrical energy or if such service is no longer available or suitable for
Sublessee's requirements.

                   g.        All sums payable under Sections 2(d) and (f)
hereof shall be hereinafter referred to collectively as "Additional Rent".  All
payments of Additional Rent under the terms of this Sublease shall be paid by
Sublessee in lawful money of the United States at the office of Sublessor set
forth above, or at such other place as Sublessor may designate in writing,
without any notice, demand, setoff or deduction whatsoever.  Sublessor shall
provide Sublessee, from time to time, with statements specifying the amount and
payment





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dates for the installments of Additional Rent due hereunder, accompanied by
copies of any related statements delivered to Sublessor by Landlord under the
Lease and such other evidence of such expenses as Sublessee may reasonably
request, and Sublessee shall pay such Additional Rent in the amounts and on the
dates so specified.  Sublessor's failure to render such statement with respect
to any Additional Rent shall not prejudice Sublessor's right to thereafter
render such statement with respect to such Additional Rent or with respect to
any subsequent Additional Rent.

                   h.        If any item of Fixed Rent or Additional Rent is
not paid within five (5) days of the due date of such payment, Sublessee shall
pay to Sublessor a late charge of a sum equal to two (2%) percent per annum
above the then current prime rate charged by Citibank, N.A. or its successor of
the amount unpaid computed from and including the date such payment was due up
to but not including the date of payment.  Such late charge shall be paid as
liquidated damages and not as interest or a penalty payment.  In addition, such
charge shall be construed as Additional Rent and shall be due and payable with
the next monthly installment of Fixed Rent.  The payment of such charge on the
part of the Sublessee or the acceptance thereof by Sublessor shall not be
deemed a waiver of any other remedies available to Sublessor in connection
therewith under the provisions of this Sublease.

                   i.        All amounts payable by Sublessee to Sublessor
pursuant to this Sublease, including, without limitation, Fixed Rent and
Additional Rent, shall be deemed to be and shall constitute rent for all
purposes hereunder and, in the event of any non-payment thereof, Sublessor
shall have all of the rights and remedies provided herein, at law or in equity
for non-payment of rent.

                   j.        The provisions of this Article 2 shall survive the
expiration or earlier termination of this Sublease, but only to the extent that





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such provisions apply to the period beginning on the Commencement Date and
ending on the date of such expiration or earlier termination.

                   k.        The parties shall prepare and deliver to Landlord
at the end of each year of Sublessee's occupancy pursuant to this Sublease a
statement setting forth in line item detail all amounts paid by Sublessee to
Sublessor pursuant to this Sublease.  The purpose of such statements shall be
to enable Landlord to determine if Landlord is entitled to receive any portion
of such payments pursuant to Section 8.9 of the Lease.  By consenting to this
Sublease, Landlord has acknowledged that payments of Sublessor's amortization
of leasehold improvements pursuant to Section 2(f) (xi) hereof do not
constitute profit to Sublessor.

         3.        Subordination

                   a.        A true and correct copy of the Lease is attached
hereto and made a part hereof as Exhibit B.  Sublessee acknowledges that this
Sublease is subject and subordinate to, and Sublessee accepts this Sublease
subject to all of the terms, covenants and provisions of, the Lease and, to the
extent that the Lease is also subject and subordinate to such instruments, this
Sublease shall be subject and subordinate to all ground and underlying leases
and all mortgages which might now or hereafter affect such leases, the
leasehold estate or estates thereby created or the real property of which the
Sublet Premises forms a part, and to any and all renewals, modifications,
consolidations, replacements and extensions of the Lease and such ground or
underlying leases and mortgages.  The provisions of this Section shall be
self-operative and no further instrument of subordination shall be required to
effect such subordination.  Sublessor's execution of any certificate or other
instrument of subordination which may be requested to confirm or further effect
such subordination shall also be sufficient to confirm the same subordination
of this Sublease.  Notwithstanding





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the foregoing, Sublessee shall promptly execute any certificate or other
instrument of subordination which may be requested to confirm or further effect
such subordination.

                   b.        It is hereby agreed that Sublessor leases the
Sublet Premises to Sublessee upon all of the terms and conditions of the Lease
with respect to the Sublet Premises.  Sublessee acknowledges that prior to
executing this Sublease it has received a copy of and read the Lease and is
familiar with the contents thereof.  Sublessee covenants and agrees (i) to
perform and observe all of the terms, covenants, agreements and conditions of
the Lease on the part of the tenant thereunder to be performed and observed
with respect to the Sublet Premises to the extent the same are not modified or
amended by this Sublease, (ii) that Sublessee will not do or cause to be done
or suffer or permit any act or thing to be done which is not permitted
hereunder and would or might cause the Lease or the rights of Sublessor, as
tenant thereunder, to be cancelled, terminated or forfeited or which would make
Sublessor liable for any damages, claim or penalty and (iii) to indemnify and
hold Sublessor harmless from and against any and all actions, claims, demands,
damages, liabilities and expenses (including, without limitation, reasonable
attorneys' fees and disbursements and expenses of defense) asserted against,
imposed upon or incurred by Sublessor by reason of (a) any violation caused,
suffered or permitted by Sublessee, its agents, servants, employees or
invitees, of any of the terms, covenants and conditions of the Lease or this
Sublease or (b) any damage or injury to persons or property occurring upon or
in connection with Sublessee's use or occupancy of the Sublet Premises and/or
the buildings in which the Leased Premises are located (the "Buildings"),
except to the extent any of the same may be caused by any act or omission of
Sublessor, its agents or representatives.

                   c.        All of the terms, covenants, conditions and 
agreements of





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the Lease are incorporated herein as if Sublessor were the "Landlord"
thereunder (except that where applicable, such references shall also be deemed
include a reference to Landlord), Sublessee were the "Tenant" thereunder and
the Sublet Premises were the "Premises" thereunder, except to the extent the
terms of the Lease are inconsistent herewith or are otherwise inapplicable and
except that the following provisions of the Sublease shall not be binding on
Sublessor and Sublessee: Article 1 (Reference Data) (except to the extent the
same describes "Permitted Uses"), Section 2.1 (Premises), Section 3.1
(Condition and Delivery of the Premises), Section 3.4 (regarding CPI Increases,
as described in the First Amendment) [by this deletion it is intended only that
the Fixed Rent payable by Sublessee pursuant to Section 2(a) hereof (which
includes a calculation incorporating the CPI Increase) shall not be further
increased by the CPI Increase], Section 6.1 (Annual Fixed Rent), Section 6.4
(Security Deposit), Section 7.1 (Landlord's Duties), Section 7.3 (Tenant to Pay
for All Utilities), Section 8.9 (Assignment and Subletting), Section 8.12
(Tenant's Financial Statements), the first sentence of Section 10.1 (Repair and
Restoration of Casualty Loss), the second sentence of Section 10.3 (Termination
for Major Damage or if Damage at End of Term), the second sentence of Section
10.4 (Eminent Domain), Section 14.1 (Notices), Section 14.3 (Limitation of
Landlord's Liability), Section 14.8 (No Broker), Sections 14.12 and 14.13
(regarding Therion Biologics Corporation), Exhibit 1 (Premises), Exhibit 3
(Tenant's Work) and Exhibit 4 (Tenant's Property), Exhibit A to the First
Amendment (Premises) and Exhibit B to the First Amendment (Tenant's Work).  In
addition, the following provisions of the Sublease shall be changed as follows:
Section 6.2 (Additional Rent; Taxes and Operating Expenses) shall be modified
as described in Article 2 hereof; the second sentence in Section 10.1 shall
only apply to improvements made by Sublessee; references in Article 10 to
Landlord's





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obligation to repair or restore the Premises shall be deemed only to refer to
Landlord, and not to Sublessor; Sublessor shall have no obligation to pay for
any of Sublessee's moving expenses pursuant to Sections 14.15 or 14.16; rather,
Sublessee shall only be entitled to receive Sublessee's Proportionate Share of
any such amounts received by Sublessor from Landlord.  Any lengths of time set
forth in the Lease for the doing of acts (as opposed to the payment of any
monies) are changed for the purposes of this Sublease so that the time of
Sublessor is three (3) days more than the time of Landlord and the time of
Sublessee is three (3) days less than the time of Sublessor, as landlord and
tenant, respectively, under the Lease, but in no event shall any such time
period be shortened to less than three (3) days.

                   d.        Sublessee agrees that notwithstanding anything
contained in this Sublease to the contrary, except in connection with any
negligent or intentional act or omission by Sublessor or its agents or
representatives, Sublessor shall not be obligated to perform any service of any
nature whatsoever (including, without limitation, the furnishing of heat,
electrical energy, air conditioning, elevator service, cleaning, window washing
or rubbish removal services), nor shall Sublessor be obligated to make any
repairs, alterations or improvements in, on or about the Sublet Premises or to
comply with any violations of law with respect thereto, nor shall Sublessor be
required to restore the Sublet Premises following the occurrence of a fire or
other casualty, nor shall Sublessor be liable to Sublessee under any
representation or warranty made by the Landlord in the Lease, it being
understood, and Sublessee hereby so agrees, that subject to the provisions of
this Article 3, Sublessee shall look solely to the Landlord for the performance
of any and all such services, the making of all repairs, alterations or
improvements, the compliance with violations of law, the restoration of the
Sublet Premises





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following fire or other casualty, and compliance with all such representations
and warranties, subject in each case to the terms of the Lease and this
Sublease.

                   e.        Notwithstanding the provisions of Section 3(d)
above, if at any time during the Term the services or other obligations
required to be provided or performed by Landlord under the Lease are not
furnished or performed or are improperly furnished or performed, upon receipt
of written request from Sublessee specifying the service or obligation as to
which the Landlord is in default, Sublessor shall cooperate with Sublessee in
seeking Landlord's compliance with its obligations under the Lease with respect
to the Sublet Premises, provided that (i) the Landlord's failure to furnish the
service or to perform the obligation in question does not result from any act
of Sublessee or by reason of any other cause or event which, under the terms of
the Lease or this Sublease, would excuse the Landlord from the furnishing or
performance thereof, and (ii) Sublessor's cooperation with Sublessee will not
cause Sublessor to be in default under the Lease.  It is further agreed that
Sublessor shall not be responsible if said efforts of Sublessor shall be
unsuccessful unless Landlord's failure to comply with its obligations under the
Lease results from Sublessor's being in default under the Lease or from
Sublessor's negligence or willful misconduct.  Sublessee shall indemnify and
reimburse Sublessor for any and all reasonable out of pocket costs and
expenses, including without limitation reasonable attorneys' fees, incurred by
Sublessor in connection therewith.  If Landlord shall default in any of its
obligations to Landlord with respect to the Sublet Premises, Sublessee shall
also be entitled to enforce Sublessor's rights with respect thereto under the
Lease directly against Landlord.

                   f.        Whenever in the Lease it is provided that the 
consent of





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the landlord therein (Landlord herein) is required for any action on the part
of the tenant, for the purposes of this Sublease the consent of both Sublessor
and Landlord shall be required.  Sublessor's refusal to consent to or approve
anything hereunder shall not be deemed unreasonable if Landlord has refused and
is required to give a corresponding consent or approval under the Lease.

                   g.        Notwithstanding anything to the contrary contained
in this Sublease or in the Lease, (i) Sublessee shall not be deemed to have
assumed, and Sublessee shall not be obligated to perform, any of Sublessor's
obligations under the Lease which obligations are required to be performed
during any period before the Commencement Date or after the Expiration Date of
this Sublease or which are attributable to any period prior to the Commencement
Date or subsequent to the Expiration Date of this Sublease, (ii) except as
otherwise expressly provided in this Sublease, no representation or warranty
made by Sublessor as tenant under the Lease shall be deemed a representation or
warranty of Sublessee, and (iii) in no event shall Sublessee be liable for, or
be required to indemnify, defend or hold Sublessor harmless from or against any
claim, cost, expense, liability, loss or damage arising by reason of any event,
act or omission of any person other than Sublessee or any other party for whom
Sublessee is legally responsible, occurring before the Commencement Date or
after the Expiration Date of this Sublease.

                   h.        Sublessor hereby represents and warrants that (i)
it is not and, to the best of its knowledge, the Landlord is not, in default in
the performance of any of their respective obligations under the Lease; (ii)
except as reflected in Exhibit B attached hereto, the Lease has not been
amended or modified in any respect and is in full force and effect; (iii)
Sublessor has not received any notice from the Landlord of any default by
Sublessor of any of its obligations as tenant under the Lease or from any
person of a violation with





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respect to the Buildings or the Sublet Premises of any law or requirement of
any public authority except violations or defaults which have been cured; and
(iv) on or before the Commencement Date, Sublessor has complied with all
requirements of the Lease which are conditions precedent to this Sublease.

         4.        Condition of Premises; Alterations; Surrender.

                   a.        Sublessee agrees that it enters into this Sublease
without any representations or warranties, express or implied, by Sublessor,
its agents, representatives, employees, servants, brokers or any other person,
as to the present or future condition of the Sublet Premises or the
appurtenances thereto or any improvements therein or thereon.  In connection
therewith, Sublessee represents that it has made a thorough examination and
inspection of the Sublet Premises and is familiar with the conditions thereof
and accepts the Sublet Premises in its "as is" condition on the date hereof,
reasonable wear and tear excepted, and that Sublessor shall not be obligated to
make any repairs or alterations thereto in preparation for Sublessee's
occupancy.

                   b.        Sublessee shall make no installations, alterations
or improvements without the prior written consent of Sublessor and the Landlord
or any other party whose consent is required under the Lease.  Sublessor shall
not unreasonably withhold its consent thereto provided Landlord and any other
party whose consent is required shall have consented in writing to such
installation, alterations or improvements.  Sublessor shall use its best
efforts to obtain Landlord's consent to any alterations, installations and
improvements proposed by Sublessee with respect to the Sublet Premises that
have been approved by Sublessor.  All such installations, alterations or
improvements shall, at Sublessee's expense, be made in compliance with and
subject to Sections 4.1 and 7.6 of the Lease and shall be performed so as to
minimize interference with any other occupant of the balance of the Leased
Premises and the Buildings.





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                   c.        Upon the expiration or earlier termination of the
Term, Sublessee shall quit and surrender to Sublessor the Sublet Premises,
broom clean, in good order and condition, ordinary wear and tear excepted.  If
Sublessee shall not quit and surrender the Sublet Premises as required hereby
by the last date of the Term, then it shall indemnify and hold Sublessor
harmless from and against all claims, liabilities, damages and costs (including
without limitation reasonable attorneys' fees but not including consequential
damages) incurred by Sublessor by reason of such failure so to quit and
surrender the Sublet Premises.  In addition, Sublessee agrees that if
possession of the Sublet Premises is not surrendered to Sublessor within
twenty-four (24) hours after the date of the expiration or sooner termination
of the Term, then Sublessee shall pay to Sublessor as liquidated damages for
each month and for each portion of any month during which Sublessee holds over
in the Sublet Premises after the expiration or sooner termination of the Term,
a sum equal to 150% of the sum of (i) the Fixed Rent payable under this
Sublease during the last month of the Term and (ii) the average monthly
aggregate of Additional Rent which was payable under this Sublease during the
last six (6) months of the Term.  Sublessee's obligation to observe or perform
this covenant shall survive the expiration or earlier termination of the Term.

         5.        Insurance

                   a.        Sublessee shall provide at the Sublessee's sole
cost and expense, and keep in full force, at all times during the Term of this
Sublease, the insurance required under Article 9 of the Lease, naming
Sublessor, Sublessee and Landlord as insured parties, including without
limitation (i) personal liability insurance and (ii) casualty insurance, but
only with respect to the contents of the Subleased Premises.  Sublessee further
covenants and agrees, at its expense, to take out and maintain at all times all
necessary workmen's





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compensation insurance covering all persons employed by the Sublessee in and
about the Sublet Premises.

                   b.        Sublessor shall maintain all other insurance
required under the Lease, except that Sublessor shall not be responsible for
insuring Sublessee's personalty and shall name Sublessee as an additional
insured thereunder.

                   c.        Sublessor and Sublessee agree to use their best
efforts to obtain from their respective insurance companies insuring them
against damage by fire or other casualty to the Buildings and Sublet Premises,
as the case may be, and/or the contents thereof, appropriate endorsements on
their insurance policies pursuant to which the insurance companies waive their
rights of recovery by way of subrogation or agree that such policies shall not
be invalidated should the insured waive in writing, prior to a loss, any or all
right of recovery against any parties for losses covered by such policies, and
so long as such endorsements remain in effect on the respective insurance
policies and do not invalidate such insurance policies, Sublessor and Sublessee
hereby each waive any right of recovery against the other for any loss or
damage to its respective property or the property of others covered by such
insurance.  If such waivers of recovery by way of subrogation are not available
or are only available at an additional premium, then the party benefitting
therefrom may waive such requirement, or pay any such additional premium.

                   d.        The Sublessee shall deliver to the Sublessor upon
the execution of this Sublease, a copy of the policies of insurance required
pursuant to this Article, together with proof of payment of the annual premium
therefor.  Each policy maintained by Sublessor or Sublessee pursuant to the
terms hereof shall contain an agreement whereby the insurer agrees that such
policy may not be cancelled without at least ten (10) days' prior written
notice





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to Sublessee or Sublessor and Landlord, as appropriate.  Each party shall
deliver to the other certificates evidencing the renewal of such insurance
policies (or new policies) not less than ten (10) days prior to the expiration
date of each such policy.  All such insurance shall be maintained by Sublessor
or Sublessee with an insurer reasonably satisfactory to the other party.

         6.        Notices.

                   a.        All notices, demands, requests and other
communications (collectively "Notices") which either party may desire or be
required to give to the other hereunder shall be in writing and shall be served
personally, by overnight mail service, or mailed by registered or certified
mail, return receipt requested, postage prepaid, addressed as follows:

                                    To Sublessor at:


                                    Oncogene Science, Inc.
                                    80 Rogers Street
                                    Cambridge, Massachusetts 02412
                                    Attention: Steven Peltzman

                                    with copies to:

                                    Oncogene Science Inc.
                                    106 Charles Lindbergh Boulevard
                                    Uniondale, New York 11553
                                    Attention: Robert Van Nostrand

                                    and

                                    Squadron, Ellenoff, Plesent & Sheinfeld, LLP
                                    551 Fifth Avenue
                                    New York, New York 10176
                                    Attention: Joel I. Papernik, Esq.





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                                    and

                                    The Trustees of The Cambridge East Trust
                                    c/o Beal And Company Inc.
                                    177 Milk Street
                                    Boston, Massachusetts 02109
                                    Attention: Robert L. Beal

                                    To Sublessee at:

                                    Calbiochem-Novabiochem Corporation
                                    10394 Pacific Center Court
                                    San Diego, California  92121
                                    Attention: Stelios B. Papadopoulos

                                    with copies to:

                                    Willkie Farr & Gallagher
                                    One Citicorp Center
                                    153 East 53rd Street
                                    New York, New York 10022
                                    Attention: Peter H. Jakes, Esq.
                                    
                                    and

                                    The Trustees of The Cambridge East Trust
                                    c/o Beal And Company Inc.
                                    177 Milk Street
                                    Boston, Massachusetts 02109
                                    Attention: Robert L. Beal

                   Notices mailed as aforesaid shall be deemed received three
(3) days after being deposited in the United States mail.  Notices personally
delivered shall be deemed received upon such delivery.  Notices sent by
overnight mail service shall be deemed received the day after delivery to such
overnight mail service.  Either party may change its address for the receipt of
Notices by giving Notice to the other party in the manner aforesaid.  Each of
Sublessor and Sublessee shall, within two (2) days after receipt of any notice
served upon it by Landlord pursuant to the terms of the Lease, deliver a copy
of such notice to the other party.





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         7.        Assignment.

                   a.        Sublessee shall not have the right (i) to assign
or otherwise transfer this Sublease, (ii) to sublet the Sublet Premises or any
portion thereof whether by operation of law or otherwise, (iii) to mortgage,
pledge or encumber this Sublease or the Sublet Premises or any part thereof or
(iv) to advertise or authorize a broker or agent to advertise for a subtenant
or assignee without, in each instance, the prior written consent of Sublessor
(which may be withheld in the sole and absolute discretion of Sublessor) and of
Landlord.  Sublessee covenants and agrees that it shall not submit any request
for any such approval to Landlord without first having received Sublessor's
prior written consent.  Notwithstanding the fact that the terms and provisions
of Section 8.9 have not been incorporated into this Sublease, it is
acknowledged and agreed that each assignment or subletting under this Article
shall be subject to all of the terms, covenants, agreements and conditions of
this Sublease and the Lease.  The consent by Sublessor and Landlord to an
assignment or subletting shall not be construed to relieve Sublessee from
obtaining the express written consent of Sublessor and Landlord to any further
assignment or subletting.  No assignment or sublease shall release Sublessee
from primary liability under this Sublease.

                   b.        Sublessor shall not have the right to assign or
otherwise transfer the Lease, or to sublet any portion of the Leased Premises
in which the Sublessee shall have any rights at the time of such transaction
pursuant to that certain Shared Services Agreement or that certain Transitional
Services Agreement, each dated the date hereof and each being between Sublessor
and Sublessee, whether by operation of law or otherwise, without, in each
instance, the prior written consent of Sublessee as to the identity of such
assignee or subtenant (which shall not be unreasonably withheld or delayed, and
which





                                     - 17 -
   18


consent may not be withheld on the basis of the creditworthiness, net worth or
other similar factors in respect of such party) and, except as otherwise
expressly provided in the Lease, of Landlord.  The consent by Sublessee to such
an assignment or subletting shall not be construed to relieve Sublessor from
obtaining the express written consent of Sublessee to any further assignment or
subletting.

                   c.        Each of the parties hereby agrees that in the
event such party (the "Offeror") wants to assign the Lease (in the case of
Sublessor) or this Sublease (in the case of Sublessee), or to sublet all or any
portion of its space in the Buildings, the Offeror shall not so assign or
sublet, or offer to any person the right to so acquire or sublease, unless and
until the Offeror shall have made a "ROFO Offer" (as hereinafter defined) to
the other party (the "Offeree") and the Offeree shall have had the opportunity
to accept such ROFO Offer as set forth below.  A "ROFO Offer" is a written
offer given by the Offeror to the Offeree stating that the Offeror desires to
assign its Lease or Sublease or sublet all or a designated portion of its space
for a specified period of time.  An assignment of the Lease or the Sublease
pursuant to a ROFO Offer shall be for no consideration, and a sublease of any
space pursuant to a ROFO Offer shall be at the same rent and on the same terms
as those specified herein, pro rated as appropriate.  The Offeree shall then
have the right to accept the ROFO Offer by giving the Offeror written notice of
such acceptance within fifteen (15) days after its receipt of the ROFO Offer.
If the Offeree shall so accept the ROFO Offer, then the parties shall
diligently and in good faith document such transaction and seek to obtain such
consents as may be necessary.  If the Offeree rejects or fails to timely
respond to the ROFO Offer, then the Offeror shall have the right to seek to so
assign or sublet, subject in all respects to the provisions of Sections 7(a)
and (b) above.  If the





                                     - 18 -
   19


Offeror shall not complete such transaction within six (6) months from the date
of the Offeree's rejection, then the provisions of this Section shall again be
operable with respect to any such transaction.  The parties acknowledge that
any assignment or sublease to Sublesee pursuant to a ROFO Offer shall be
subject to Section 8.9 of the Lease.  By consenting to this Sublease, Landlord
has acknowledged that any assignment or sublease to Sublesor pursuant to a ROFO
Offer such that Sublessor is restored to possession of all or any portion of
the Sublet Premises shall not require Landlord's consent and shall not be
subject to Section 8.9 of the Lease.

         8.        No Waiver.

                   All rights and remedies of Sublessor and Sublessee
enumerated herein and in the Lease shall be cumulative, shall not exclude any
other right or remedy allowed at law or in equity, and said rights or remedies
may be exercised and enforced concurrently.  No waiver by Sublessor or
Sublessee of any breach or any agreement or provision herein contained shall be
deemed a waiver of any preceding or succeeding breach thereof or of any other
agreement or provision herein contained.  No extension by Sublessor of time for
performance of any obligations or acts shall be deemed an extension of time for
performance of any other obligations or acts.

         9.        Quiet Enjoyment.

                   If and so long as Sublessee is not in default beyond all
applicable notice and cure periods of any of its obligations of this Sublease
on its part to be performed, Sublessee shall quietly have and enjoy the Sublet
Premises during the Term of this Sublease without hindrance or molestation by
anyone claiming by, through or under Sublessor, subject, however, to the
exceptions, reservations and conditions hereof.  Sublessor covenants and agrees
that, at all times during the Term of this Sublease, Sublessor shall fully and





                                     - 19 -
   20


faithfully comply with and perform the terms and conditions of the Lease on its
part to be performed.  Sublessor further covenants and agrees that it shall not
do anything that would or could cause the Lease to be canceled, terminated,
forfeited, surrendered or modified so as to (a) adversely affect (i) the rights
or obligations of Sublessor thereunder or in and to the Leased Premises or (ii)
the rights or obligations of Sublessee under this Sublease or in and to the
Sublet Premises, or (b) cause an interruption in any of the services to be
provided by the Landlord pursuant to the Lease.  Sublessor covenants and agrees
to indemnify and hold Sublessee harmless from and against any and all actions,
claims, demands, damages, liabilities and expenses (including, without
limitation, reasonable attorneys' fees, disbursements and expenses of defense)
asserted against, imposed upon or incurred by Sublessee by reason of (a) any
violation caused, suffered or permitted by Sublessor, its agents, servants,
employees or invitees, of any of the terms, covenants and conditions of the
Lease or this Sublease or (b) any damage or injury to persons or property
occurring upon or in connection with Sublessor's use or occupancy of the Leased
Premises and/or the Buildings, except to the extent any of the same may be
caused by any act or omission of Sublessee, its agents or representatives.

         10.       Successors and Assigns.

                   The provisions of this Sublease shall be binding upon and
inure to the benefit of the parties hereto and, subject to the restrictions
above set forth in respect of Sublessee, their respective successors and
assigns.

         11.       Sublessor.

                   The term "Sublessor" used in this Sublease shall mean only
the tenant in possession of the Lease so that in the event of any assignment or
transfer of the Lease, the party so assigning or transferring the Lease shall,
provided that its immediate successor shall have a net worth at least equal to





                                     - 20 -
   21


the remaining obligations of the tenant under the Lease in respect of Annual
Fixed Rent less the remaining obligations of Sublessee in respect of Fixed Rent
hereunder, be and hereby is entirely freed and relieved of all covenants and
obligations of Sublessor hereunder thereafter occurring and it shall be deemed
and construed as a covenant running with the land without further agreement
between the parties and the assigns or transferees of the Lease, that said
assignee or transferee had assumed and agreed to perform any and all covenants
and obligations of Sublessor hereunder thereafter.

         12.       [INTENTIONALLY OMITTED]

         13.       Sublessor's Right to Cure.

                   a.        If Sublessee shall at any time fail to make any
payment or perform any act on its part required to be made or performed by the
terms hereof, or if Sublessor shall receive a notice of default from the
Landlord, which default arises out of or in connection with Sublessee's actions
or failure to act under this Sublease, then Sublessor, after five (5) days'
written notice to Sublessee and without waiving or releasing Sublessee from any
obligation of Sublessee contained in this Sublease, may (but shall be under no
obligation to) make any such payment or perform any such act on Sublessee's
part to be made or performed as in this Sublease provided or in order to cure
the default under the Lease and may enter upon the Sublet Premises for that
purpose and take all such other actions as may be necessary therefor.

                   b.        Any and all sums so paid by Sublessor and all
costs and expenses reasonably incurred by Sublessor in connection with the
performance of any such act, including without limitation reasonable attorneys'
fee, together with interest thereon at the rate of 2% per annum above the then
current prime rate charged by Citibank, N.A. or its successor from the
respective dates of Sublessor's making of each such payment or incurring of
each such cost and





                                     - 21 -
   22


expense shall constitute Additional Rent payable by Sublessee under this
Sublease and shall be paid by Sublessee to Sublessor within five (5) days after
rendition of a bill or statement to Sublessee therefor.

         14.       Leasehold Estate.

                   Sublessor cannot grant or convey any greater estate, rights
or interest by virtue of this Sublease than Sublessor has received under the
terms of the Lease, and Sublessee acknowledges that it has not received and
cannot receive any greater estate, rights or interest pursuant to this Sublease
than Sublessor has received under the Lease.

         15.       Broker.

                   a.        Each of Sublessor and Sublessee warrants and
represents to the other that it has not dealt with any broker or agent in
connection with this Sublease.  Each party agrees to indemnify and hold the
other harmless from and against any and all claims, costs, liabilities and
expenses (including without limitation reasonable attorneys' fees) which may be
imposed upon or incurred by or asserted against such other party by any broker
or agent alleging to have dealt with the party making such indemnification in
connection with this Sublease.  The provisions of this Article shall survive
the expiration or earlier termination of this Sublease.

         16.       Use of the Sublet Premises.

                   Sublessee shall use the Sublet Premises only in accordance
with the uses set forth in Article 1 of the Lease.  Sublessee shall obtain, at
its sole cost and expense, all permits, licenses, consents and approvals
required for the operation of its business at the Sublet Premises.

         17.       Certificates.

                   Each Party shall, within thirty (30) days after demand,
furnish to the other a certificate, duly acknowledged, certifying (a) that this
Sublease





                                     - 22 -
   23


is in full force and effect, (b) that it knows of no default hereunder on the
part of the other party or, if it has reason to believe that such a default
exists, the nature thereof in reasonable detail, (c) the amount of the Fixed
Rent and Additional Rent being paid, (d) that this Sublease has not been
modified or, if it has been modified, setting forth the terms and dates of such
modifications, (e) as to the form and content of this Sublease by annexing a
copy hereof to such certificate and (f) to such other matters as may be
reasonably requested by the other party.

         18.       Condemnation.

                   If the whole or substantially all of the Sublet Premises or
the access thereto shall be taken or condemned by any competent authority for
any public or quasi-public use this Sublease shall cease and terminate on the
date of taking of possession in such proceeding.  If the Lease is terminated
pursuant to Section 10.4 thereof, this Sublease shall cease and terminate on
the date the Lease terminates.  Upon a partial taking, unless this Sublease is
terminated as above provided, this Sublease shall continue in force as to the
remainder of the Sublet Premises, and the Fixed Rent and Additional Rent shall
be diminished by the same proportion which rental allocable to the Sublet
Premises under the terms of this Sublease shall abate under the Lease.

         19.       Damage or Destruction of the Sublet Premises.

                   If the Lease shall be terminated by either the Landlord or
Sublessor pursuant to Section 10.3 of the Lease, this Sublease shall cease and
terminate on the effective date of the termination of the Lease.  Sublessee
shall forthwith vacate and surrender the Sublet Premises on or before said date
and the Fixed Rent and Additional Rent (or the portion thereof, if any, not
abated from the date of the damage or destruction) shall be apportioned as of
said termination date.  Sublessee's right to an abatement or apportionment of





                                     - 23 -
   24


Fixed Rent and Additional Rent or to repairs shall be dependent upon whether or
not Sublessor is entitled to the same under Section 10.3 of the Lease.

         20.       Operating Agreement.

                   Sublessor hereby represents and warrants that no portion of
the Sublet Premises constitute any of the Shared Facilities as defined in that
certain Operating Agreement, dated as of October 4, 1991 (the "Operating
Agreement") between AbT Acquisition Corp. (Sublessor's predecessor in interest)
and Therion Biologics Corporation ("Therion"), and that Therion shall have no
rights whatsoever in respect of the Sublet Premises pursuant to such Agreement
or otherwise.  Notwithstanding the foregoing to the contrary, this Sublease is
subject and subordinate to the Operating Agreement.

         21.       Miscellaneous

                   a.        All provisions of this Sublease and any variations
thereof shall be deemed to refer to the masculine, feminine, neuter, singular
or plural, as the identity of the person or persons may require.

                   b.        If any of the terms and provisions of this
Sublease are in violation of or prohibited by any law, statute or ordinance, or
such terms or provisions are found to be unenforceable by any court of
competent jurisdiction, then such terms or provisions shall be of no force and
effect; provided, however, that all of the other terms and provisions of this
Sublease shall continue in full force and effect.

                   c.        The captions or headings of each Article hereof
are inserted only as a matter of convenience and for reference and shall in no
way define, limit or describe the scope of this Sublease or of any Article or
section hereof or the intent of any provision hereof.  The use of this Sublease
of such words as "hereof," "hereunder" "herein" and "hereby" are deemed to be
references to this Sublease as a whole.





                                     - 24 -
   25


                   d.        This Sublease contains the entire agreement
between the parties, and any agreement hereafter made shall be ineffective to
change, modify or discharge it in whole or in part unless such agreement is in
writing and signed by the party against whom enforcement of the change,
modification or discharge is sought.  This Sublease shall bind and inure to the
benefit of the parties hereto and their respective successors and, subject to
this Sublease, their respective assigns.

                   e.        This Sublease shall be governed by and construed
in accordance with the laws of the State of Massachusetts without regard to
conflicts of law principles.

                   f.        Sublessor and Sublessee hereby mutually waive, to
the extent permitted by law, the right to a jury trial in any action or legal
proceeding between the parties arising out of this Sublease or Sublessee's
occupancy of the Sublet Premises.

                   g.        Wherever in this Sublease Sublessor's consent or
approval is required, if Sublessor shall delay or refuse such consent or
approval, Sublessee in no event shall be entitled to make, nor shall Sublessee
make, any claim, and Sublessee hereby waives any claim, for money damages
(including, without limitation, by set-off, counterclaim or defense) based upon
any claim or assertion by Sublessee that Sublessor unreasonably withheld or
delayed its consent or approval.  Sublessee's sole remedy shall be an action or
proceeding to enforce any such provisions, for specific performance, injunction
or declaratory judgment.





                                     - 25 -
   26


         IN WITNESS WHEREOF, Sublessor and Sublessee have executed this
Sublease as of the date and year first above written.

                             SUBLESSOR:

                             ONCOGENE SCIENCE, INC.



                             By:
                                ------------------------------------
                                 Name:
                                 Title:



                             SUBLESSEE:

                             CALBIOCHEM-NOVABICHEM CORPORATION



                             By:
                                ------------------------------------
                                 Name:
                                 Title:





                                     - 26 -