Document:

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                           CALYPTE BIOMEDICAL CORPORATION

                             1995 DIRECTOR OPTION PLAN

                          AMENDED AS OF NOVEMBER 18, 1999

     1.   Purposes of the Plan.  The purposes of this Director Option Plan
are to attract and retain the best available personnel for service as Outside
Directors (as defined herein) of the Company, to provide additional incentive
to the Outside Directors of the Company to serve as Directors, and to
encourage their continued service on the Board.

     All options granted hereunder shall be "non-statutory stock options."

     2.   Definitions.  As used herein, the following definitions shall apply:

          (a)  "Board" means the Board of Directors of the Company.

          (b)  "Code" means the Internal Revenue Code of 1986, as amended.

          (c)  "Common Stock" means the Common Stock of the Company.

          (d)  "Company" means Calypte Biomedical Corporation, a Delaware
corporation.

          (e)  "Continuous Status as a Director" means the absence of any
interruption or termination of service as a Director.

          (f)  "Director" means a member of the Board.

          (g)  "Employee" means any person, including officers and Directors,
employed by the Company or any Parent or Subsidiary of the Company.  The payment
of a Director's fee by the Company shall not be sufficient in and of itself to
constitute "employment" by the Company.  Any person who is not employed by the
Company but who is engaged by the Company to render services as a consultant is
not considered an Employee under this Plan.

          (h)  "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

          (i)  "Fair Market Value" means, as of any date, the value of Common
Stock determined as follows:

               (i)   If the Common Stock is listed on any established stock
exchange or a national market system, including without limitation the National
Market System of the National Association of Securities Dealers, Inc. Automated
Quotation ("NASDAQ") System, the Fair Market Value of a Share of Common Stock
shall be the closing sales price for such stock (or the closing bid, if no sales
were reported) as quoted on such system or exchange (or the exchange with the
greatest volume of trading in Common Stock) on the date of grant, as reported in
The Wall Street Journal or such other source as the Board deems reliable;

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               (ii)  If the Common Stock is quoted on the NASDAQ System (but not
on the National Market System thereof) or regularly quoted by a recognized
securities dealer but selling prices are not reported, the Fair Market Value of
a Share of Common Stock shall be the mean between the bid and asked prices for
the Common Stock on the last market trading day prior to the day of
determination, as reported in The Wall Street Journal or such other source as
the Board deems reliable, or;

               (iii) In the absence of an established market for the Common
Stock, the Fair Market Value thereof shall be determined in good faith by the
Board.

          (j)  "Immediate Family Members" means the spouse, children or
grandchildren of the Optionee.

          (k)  "New Director" means any person elected to the Board to fill a
vacancy and/or at an annual meeting of the Company's stockholders who was not
serving as a Director immediately prior to such election.  In addition, the
Board shall determine whether a person who had previously been a Director but
was not a Director immediately prior to his or her election shall be considered
a New Director under the Plan.

          (l)  "Option" means a stock option granted pursuant to the Plan.

          (m)  "Optioned Stock" means the Common Stock subject to an Option.

          (n)  "Optionee" means an Outside Director who receives an Option.

          (o)  "Outside Director" means a Director who is not an Employee.

          (p)  "Parent" means a "parent corporation", whether now or hereafter
existing, as defined in Section 424(e) of the Code.

          (q)  "Plan" means this Director Option Plan.

          (r)  "Share" means a share of the Common Stock, as adjusted in
accordance with Section 10 of the Plan.

          (s)  "Subsidiary" means a "subsidiary corporation", whether now or
hereafter existing, as defined in Section 424(f) of the Internal Revenue Code of
1986.

          (t)  "Term of Office" means the period of time commencing with the
date of any annual meeting of the Company's stockholders at which Directors are
elected and the date of the next subsequent stockholders' meeting at which
Directors are elected.

     3.   Stock Subject to the Plan.  Subject to the provisions of Section 10 of
the Plan, the maximum aggregate number of Shares which may be optioned and sold
under the Plan is 350,000 Shares (the "Pool") of Common Stock.  The Shares may
be authorized but unissued, or reacquired Common Stock.

     If an Option should expire or become unexercisable for any reason without
having been exercised in full, the unpurchased Shares which were subject thereto
shall, unless the Plan shall have been terminated, become available for future
grant under the Plan.

     4.   Administration of and Grants of Options under the Plan.

                                        -2-

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          (a)  Procedure for Grants.  The provisions set forth in this
Section 4(a) shall not be amended more than once every six months, other than
to comport with changes in the Code, the Employee Retirement Income Security
Act of 1974, as amended, or the rules thereunder.  All grants of Options to
Outside Directors under this Plan shall be discretionary provided such grants
are made strictly in accordance with the following provisions:

               (i)   No person shall have any discretion to select which
Outside Directors shall be granted Options or to determine the number of
Shares to be covered by Options granted to Outside Directors.

               (ii)  The Board shall have discretionary authority to
determine the number of shares of Common Stock to be granted to Optionees on
the date on which each person first becomes a Director, provided that during
any given Term of Office the number of Options granted to each newly-elected
Director shall be equal.

               (iii) The Board shall have discretionary authority to determine
the number of Options to be granted to each re-elected Director, provided a)
that in any given Term of Office the number of Options granted will be the same
for each such re-elected Director, and b) that if such re-elected Director has
not served on the Board for at least six (6) months prior to the date of the
Company's Annual Meeting of Shareholders the Board may adjust the number of
Options granted to such Director.

          (b)  Option Grants.  Each Option granted hereunder will include the
following terms:

               (i)   The term of the Option will be ten (10) years.

               (ii)  The Option will be exercisable at any time during the term
of the Option to the extent that the Option has become vested, regardless of
whether the Optionee has terminated service as a member of the Board, provided
however that if an Optionee is removed from the Board, the Option will terminate
if it is not exercised within 90 days of the date of such removal, but in no
event later than the expiration of the ten (10) year term of the Option.

               (iii) The exercise price per Share will be 100% of the fair
market value per Share on the date of grant of the Option.

               (iv)  During the period that an Optionee serves as a Director,
the Option will vest monthly at a rate of 8.33% per month over the twelve (12)
month period commencing with the date of election of the Optionee as Director.
The Option will vest at such rate on the first day of each month subsequent to
such election, provided that such Option will become vested and fully
exercisable on the date of the next annual meeting of stockholders if such
meeting occurs less than twelve months after the date of the grant.

               (v)   In the event that any Option granted under the Plan would
cause the number of Shares subject to outstanding Options plus the number of
Shares previously purchased under Options to exceed the Pool, then the remaining
Shares available for Option grant shall be granted under Options to the Outside
Directors on a pro rata basis.  No further grants shall be made until such time,
if any, as additional Shares become available for grant under the Plan through
action of the Board to increase the number of Shares which may be issued under
the Plan; provided, further that such Options shall not be exercisable until
such time, if any, as the increased approved by the Board is approved by the
shareholders.

                                        -3-

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     5.   Eligibility.  Options may be granted only to Outside Directors.
All Options shall be granted in accordance with the terms set forth in
Section 4 hereof. An Outside Director who has been granted an Option may, if
he is otherwise eligible, be granted an additional Option or Options in
accordance with such provisions.

     The Plan shall not confer upon any Optionee any right with respect to
continuation of service as a Director or nomination to serve as a Director,
nor shall it interfere in any way with any rights which the Director or the
Company may have to terminate his or her directorship at any time.

     6.   Term of Plan.  The Plan shall become effective upon the earlier to
occur of its adoption by the Board or its approval by the shareholders of the
Company as described in Section 16 of the Plan.  It shall continue in effect
for a term of ten (10) years unless sooner terminated under Section 11 of the
Plan.

     7.   Form of Consideration.  The consideration to be paid for the Shares
to be issued upon exercise of an Option, including the method of payment,
shall consist of (i) cash, (ii) check, (iii) delivery of a properly executed
exercise notice together with such other documentation as the Company and the
broker, if applicable, shall require to effect an exercise of the Option and
delivery to the Company of the sale or loan proceeds required to pay the
exercise price, or (iv) any combination of the foregoing methods of payment.

     8.   Exercise of Option.

          (a)  Procedure for Exercise; Rights as a Shareholder.  Any Option
granted hereunder shall be exercisable at such times as are set forth in
Section 4 hereof, provided, however, that no Options shall be exercisable
until shareholder approval of the Plan in accordance with Section 16 hereof
has been obtained.  An Option may not be exercised for a fraction of a Share.

     An Option shall be deemed to be exercised when written notice of such
exercise has been given to the Company in accordance with the terms of the
Option by the person entitled to exercise the Option and full payment for the
Shares with respect to which the Option is exercised has been received by the
Company.  Full payment may consist of any consideration and method of payment
allowable under Section 7 of the Plan.  Until the issuance (as evidenced by
the appropriate entry on the books of the Company or of a duly authorized
transfer agent of the Company) of the stock certificate evidencing such
Shares, no right to vote or receive dividends or any other rights as a
shareholder shall exist with respect to the Optioned Stock, notwithstanding
the exercise of the Option. A share certificate for the number of Shares so
acquired shall be issued to the Optionee as soon as practicable after
exercise of the Option.  No adjustment will be made for a dividend or other
right for which the record date is prior to the date the stock certificate is
issued, except as provided in Section 10 of the Plan.

     Exercise of an Option in any manner shall result in a decrease in the
number of Shares which thereafter may be available, both for purposes of the
Plan and for sale under the Option, by the number of Shares as to which the
Option is exercised.

                                        -4-

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          (b)  Rule 16b-3.  Options granted to Outside Directors must comply
with the applicable provisions of Rule 16b-3 promulgated under the Exchange
Act or any successor thereto and shall contain such additional conditions or
restrictions as may be required thereunder to qualify for the maximum
exemption from Section 16 of the Exchange Act with respect to Plan
transactions.

          (c)  Termination of Continuous Status as a Director.  In the event
an Optionee's Continuous Status as a Director terminates, the Optionee's
vesting in his or her Options granted under this Plan will cease as of the
date of such termination.

          (d)  Death of Optionee.  In the event of an Optionee's death, the
Optionee's estate or a person who acquired the right to exercise the Option
by bequest or inheritance may exercise the Option to the extent that the
Optionee was entitled to exercise it at the date of death (but in no event
later than the expiration of its ten (10) year term).  To the extent that the
Optionee was not entitled to exercise an Option at the date of death, and to
the extent that the Optionee's estate or a person who acquired the right to
exercise such Option does not exercise such Option (to the extent otherwise
so entitled) within the time specified herein, the Option shall terminate.

     9.   Assignment or Transfer.

          (a)  All or any portion of any Option may be transferred by an
Optionee to (i) the Immediate Family Members of the Optionee, (ii) a
partnership in which such Immediate Family Members are the only partners, or
(iii) a trust or trusts for the exclusive benefit of such Immediate Family
Members, provided that (x) there may be no consideration for such transfer,
(y) the agreement pursuant to which such Options are transferred must be in a
form consistent with the Plan, and must expressly provide for transferability
in a manner consistent with this Section 9, and (z) subsequent transfers of
transferred Options shall be prohibited except those by will or the laws of
descent and distribution. Following transfer, any such Options shall continue
to be subject to the same terms and conditions as were applicable immediately
prior to transfer.  The effect of termination of the Optionee's service on
the Board of Directors shall continue to be applied with respect to the
original Optionee, following which the Options shall be exercisable by the
transferee only to the extent, and for the periods specified in the Plan on
the occurrence of such termination. Neither the Company nor the administrator
of the Plan shall have any obligation to provide the transferee with notice
of termination of an Optionee.

          (b)  Options shall be transferable only in accordance with Section
9(a) or by will or the laws of descent and distribution.

     10.  Adjustments Upon Changes in Capitalization, Dissolution, Merger, Asset
Sale or Change of Control.

                                        -5-

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          (a)  Changes in Capitalization.  Subject to any required action by
the shareholders of the Company, the number of  Shares covered by each
outstanding Option and the number of Shares which have been authorized for
issuance under the Plan but as to which no Options have yet been granted or
which have been returned to the Plan upon cancellation or expiration of an
Option, as well as the price per Share covered by each such outstanding
Option, shall be proportionately adjusted for any increase or decrease in the
number of issued Shares resulting from a stock split, reverse stock split,
stock dividend, combination or reclassification of the Common Stock, or any
other increase or decrease in the number of issued Shares effected without
receipt of consideration by the Company; provided, however, that conversion
of an convertible securities of the Company shall not be deemed to have been
"effected without receipt of consideration".  Except as expressly provided
herein, no issuance by the Company of shares of stock of any class, or
securities convertible into shares of stock of any class, shall affect, and
no adjustment by reason thereof shall be made with respect to, the number or
price of Shares subject to an Option.

          (b)  Dissolution or Liquidation.  In the event of the proposed
dissolution or liquidation of the Company, to the extent that an Option has
not been previously exercised, it will terminate immediately prior to the
consummation of such proposed action.

          (c)  Merger or Asset Sale.  In the event of a merger of the Company
with or into another corporation, or the sale of substantially all of the
assets of the Company, each outstanding Option shall be assumed or an
equivalent option shall be substituted by the successor corporation or a
Parent or Subsidiary of the successor corporation.  In the event that the
successor corporation does not agree to assume the Option or to substitute an
equivalent option, each outstanding Option shall become fully vested and
exercisable, including as to Shares as to which it would not otherwise be
exercisable, unless the Board, in its discretion, determines otherwise.  If
an Option becomes fully vested and exercisable in the event of a merger or
sale of assets, the Board shall notify the Optionee that the Option shall be
fully exercisable for a period of thirty (30) days from the date of such
notice, and the Option will terminate upon the expiration of such period.
For the purposes of this paragraph, the Option shall be considered assumed
if, following the merger or sale of assets, the option or right confers the
right to purchase, for each Share of Optioned Stock subject to the Option
immediately prior to the merger or sale of assets, the consideration (whether
stock, cash, or other securities or property) received in the merger or sale
of assets by holders of Common Stock for each Share held on the effective
date of the transaction (and if holders were offered a choice of
consideration, the type of consideration chosen by the holders of a majority
of the outstanding Shares).

     11.  Amendment and Termination of the Plan.

          (a)  Amendment and Termination.  Except as set forth in Section 4,
the Board may at any time amend, alter, suspend, or discontinue the Plan, but
no amendment, alteration, suspension, or discontinuation shall be made which
would impair the rights of any Optionee under any grant theretofore made,
without his or her consent.  In addition, to the extent necessary and
desirable to comply with Rule 16b-3 under the Exchange Act (or any other
applicable law or regulation), the Company shall obtain shareholder approval
of any Plan amendment in such a manner and to such a degree as required.

          (b)  Effect of Amendment or Termination.  Any such amendment or
termination of the Plan shall not affect Options already granted and such
Options shall remain in full force and effect as if this Plan had not been
amended or terminated.

                                        -6-

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     12.  Time of Granting Options.  The date of grant of an Option shall,
for all purposes, be the date determined in accordance with Section 4 hereof.
Notice of the determination shall be given to each Outside Director to whom
an Option is so granted within a reasonable time after the date of such grant.

     13.  Conditions Upon Issuance of Shares.  Shares shall not be issued
pursuant to the exercise of an Option unless the exercise of such Option and
the issuance and delivery of such Shares pursuant thereto shall comply with
all relevant provisions of law, including, without limitation, the Securities
Act of 1933, as amended, the Exchange Act, the rules and regulations
promulgated thereunder, state securities laws, and the requirements of any
stock exchange upon which the Shares may then be listed, and shall be further
subject to the approval of counsel for the Company with respect to such
compliance.

     As a condition to the exercise of an Option, the Company may require the
person exercising such Option to represent and warrant at the time of any
such exercise that the Shares are being purchased only for investment and
without any present intention to sell or distribute such Shares, if, in the
opinion of counsel for the Company, such a representation is required by any
of the aforementioned relevant provisions of law.

     Inability of the Company to obtain authority from any regulatory body
having jurisdiction, which authority is deemed by the Company's counsel to be
necessary to the lawful issuance and sale of any Shares hereunder, shall
relieve the Company of any liability in respect of the failure to issue or
sell such Shares as to which such requisite authority shall not have been
obtained.

     14.  Reservation of Shares.  The Company, during the term of this Plan,
will at all times reserve and keep available such number of Shares as shall
be sufficient to satisfy the requirements of the Plan.

     15.  Option Agreement.  Options shall be evidenced by written option
agreements in such form as the Board shall approve.

     16.  Shareholder Approval.  Continuance of the Plan shall be subject to
approval by the shareholders of the Company at or prior to the first annual
meeting of shareholders held subsequent to the granting of an Option
hereunder. Such shareholder approval shall be obtained in the degree and
manner required under applicable state and federal law.

                                        -7-

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                           CALYPTE BIOMEDICAL CORPORATION

                             DIRECTOR OPTION AGREEMENT

     Calypte Biomedical Corporation, a Delaware corporation (the "Company"), has
granted to _______________________ (the "Optionee"), an option to purchase a
total of [_________________________ (________)] shares of the Company's Common
Stock (the "Optioned Stock"), at the price determined as provided herein, and in
all respects subject to the terms, definitions and provisions of the Company's
Director Option Plan (the "Plan") adopted by the Company which is incorporated
herein by reference.  The terms defined in the Plan shall have the same defined
meanings herein.

     1.   Nature of the Option.  This Option is a nonstatutory option and is
not intended to qualify for any special tax benefits to the Optionee.

     2.   Exercise Price.  The exercise price is $ _______ for each share of
Common Stock.

     3.   Exercise of Option.  This Option shall be exercisable during its
term in accordance with the provisions of Sections 4 and 8 of the Plan as
follows:

          (i)   Right to Exercise.

     (a)  During the period that the Optionee serves as a Director of the
Company, this Option will vest monthly at a rate of 8.33% per month over the
twelve (12) month period commencing with the date of election or re-election
of the Optionee as Director on the first day of each month subsequent to such
election, provided that such Option will become vested and fully exercisable
on the date of the next annual meeting of stockholders if such meeting occurs
less than twelve months after the date of grant.

     (b)  This Option may not be exercised for a fraction of a share.

     (c)  In the event of Optionee's death, removal or other termination of
service as a Director, the exercisability of the Option is governed by
Sections 4 and 8 of the Plan.

          (ii)  Method of Exercise.  This Option shall be exercisable by
written notice which shall state the election to exercise the Option and the
number of Shares in respect of which the Option is being exercised.  Such
written notice, in the form attached hereto as Exhibit A, shall be signed by
the Optionee and shall be delivered in person or by certified mail to the
Secretary of the Company.  The written notice shall be accompanied by payment
of the exercise price.

     4.   Method of Payment.  Payment of the exercise price shall be by any
of the following, or a combination thereof, at the election of the Optionee:

          (i)   cash;

          (ii)  check; or

                                        -8-

<PAGE>

          (iii) surrender of other shares which (x) in the case of Shares
acquired upon exercise of an Option, have been owned by the Optionee for more
than six (6) months on the date of surrender, and (y) have a Fair Market
Value on the date of surrender equal to the aggregate exercise price of the
Shares as to which said Option shall be exercised; or

          (iv)  delivery of a properly executed exercise notice together with
such other documentation as the Company and the broker, if applicable, shall
require to effect an exercise of the Option and delivery to the Company of
the sale or loan proceeds required to pay the exercise price.

     5.   Restrictions on Exercise.  This Option may not be exercised if the
issuance of such Shares upon such exercise or the method of payment of
consideration for such shares would constitute a violation of any applicable
federal or state securities or other law or regulations, or if such issuance
would not comply with the requirements of any stock exchange upon which the
Shares may then be listed.  As a condition to the exercise of this Option,
the Company may require Optionee to make any representation and warranty to
the Company as may be required by any applicable law or regulation.

     6.   Assignment or Transfer of Option.  This Option may be transferred
to (i) the spouse, children or grandchildren of the Optionee ("Immediate
Family Members"), (ii) a partnership in which such Immediate Family Members
are the only partners, or (iii) a trust or trusts for the exclusive benefit
of such Immediate Family Members, provided that (x) there may be no
consideration for such transfer, (y) the agreement pursuant to which such
Options are transferred must be in a form consistent with the Plan, and (z)
subsequent transfers of transferred Options shall be prohibited except those
by will or the laws of descent and distribution.  Following transfer, any
such Options shall continue to be subject to the same terms and conditions as
were applicable immediately prior to transfer.  The effect of termination of
the Optionee's service on the Board of Directors shall continue to be applied
with respect to the original Optionee, following which the Options shall be
exercisable by the transferee only to the extent, and for the periods
specified in the Plan on the occurrence of such termination.  Neither the
Company nor the administrator of the Plan shall have any obligation to
provide the transferee with notice of termination of an Optionee.  The terms
of this Option shall be binding upon the transferees, executors,
administrators, heirs, successors and assigns of the Optionee.

     7.   Term of Option.  This Option may not be exercised more than ten
(10) years from the date of grant of this Option, and may be exercised during
such period only in accordance with the Plan and the terms of this Option.

                                        -9-

<PAGE>

     8.   Taxation Upon Exercise of Option.  Optionee understands that, upon
exercise of this Option, he or she will recognize income for tax purposes in
an amount equal to the excess of the then Fair Market Value of the Shares
purchased over the exercise price paid for such Shares.  Since the Optionee
is subject to Section 16(b) of the Securities Exchange Act of 1934, as
amended, under certain limited circumstances the measurement and timing of
such income (and the commencement of any capital gain holding period) may be
deferred, and the Optionee is advised to contact a tax advisor concerning the
application of Section 83 in general and the availability of a Section 83(b)
election in particular in connection with the exercise of the Option.  Upon a
resale of such Shares by the Optionee, any difference between the sale price
and the Fair Market Value of the Shares on the date of exercise of the
Option, to the extent not included in income as described above, will be
treated as capital gain or loss.

     DATE OF GRANT:

     CALYPTE BIOMEDICAL CORPORATION,

     a Delaware corporation

     By:

     Title:

     Optionee acknowledges receipt of a copy of the Plan, a copy of which is
attached hereto, and represents that he or she is familiar with the terms and
provisions thereof, and hereby accepts this Option subject to all of the
terms and provisions thereof Optionee hereby agrees to accept as binding,
conclusive and final all decisions or interpretations of the Board upon any
questions arising under the Plan.

     Dated:                   ____________________________
                              Optionee

                                        -10-<PAGE>

                                      LEASE

                                     between

                         AQUILA BIOPHARMACEUTICALS, INC.

                                    Landlord

                                       and

                             BIOMERIEUX VITEK, INC.

                                     Tenant

                             Dated: October 22, 1996

<PAGE>

                                TABLE OF CONTENTS

Section                                                                    Page
-------                                                                    ----

Table of Contents ...........................................................i
   1.  Introductory Provisions ..............................................1
       (a) Fundamental Lease Provisions .....................................1
       (b) References and Conflicts .........................................2
       (c) Exhibits..........................................................2
   2.  Premises .............................................................2
       (a) Leased Premises ..................................................2
       (b) The Property .....................................................2
       (c) Tenant's Proportionate Share......................................3
   3.  Term and Acceptance by Tenant ........................................3
       (a) Lease Term .......................................................3
       (b) Renewal Option ...................................................3
       (c) Acceptance of Leased Premises.....................................5
       (d) Permits...........................................................5
   4.  Rent  ................................................................5
       (a) Minimum Annual Rent ..............................................5
       (b) Additional Rent ..................................................5
              (i)    General ................................................5
             (ii)    Real Estate Taxes ......................................6
            (iii)    Insurance ..............................................7
             (iv)    Utility Expenses Not Separately Metered ................9
              (v)    Landlord's Enforcement Costs ...........................9
       (c) Payment of Rent ..................................................9
   5.  Use .................................................................10
       (a) Use .............................................................10
       (b) Compliance With Laws, Fire Insurance, Condition of
             Leased Premises ...............................................10
   6.  Common Areas ........................................................11
       (a) Common Areas Defined ............................................11
       (b) Landlord's Control ..............................................11
       (c) Parking Spaces ..................................................12
   7.  Rules and Regulations ...............................................12
   8.  Utilities ...........................................................12
   9.  Landlord's Right of Entry............................................12
  10.  Maintenance and Repair...............................................12
       (a) Tenant's Responsibility .........................................12
       (b) Landlord's Responsibility .......................................13
  11.  Alternations or Improvements by Tenant ..............................14
  12.  Surrender ...........................................................14
  13.  Tenant Holding Over .................................................15
  14.  Assignment and Subletting............................................15
       (a) Assignment by Tenant ............................................15
       (b) Assignment by Landlord ..........................................17
  15.  Bankruptcy  .........................................................17
  16.  Default .............................................................18
  17.  Landlord's Rights Upon Tenant's Default..............................18

                                      -i-
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18. Lender Requirements ....................................................20
       (a) Subordination ...................................................20
       (b) Attornment ......................................................20
       (c) Notice to Mortgagee Upon Landlord's Default .....................21
19. Estoppel Certificates ..................................................21
20. Damage by Fire or Other Casualty .......................................21
       (a) Restoration .....................................................21
       (b) Termination .....................................................22
       (c) Lender's Approval ...............................................23
21. Condemnation ...........................................................23
22. Landlord's Liability ...................................................24
23. Tenant's and Landlord's Liability ......................................24
24. Indemnity ..............................................................24
       (a) By Tenant .......................................................24
       (b) By Landlord .....................................................24
25. Tenant's Insurance......................................................25
       (a) Coverages .......................................................25
                (i)   Comprehensive Liability ..............................25
               (ii)   All-Risk Casualty ....................................25
              (iii)   Workers' Compensation ................................25
       (b) Policy Requirements..............................................25
       (c) No Limitation of Liability ......................................26
26. Waiver of Subrogation ..................................................26
27. No Liens Permitted; Discharged .........................................26
28. Signs, Awnings and Canopies ............................................27
29. Environmental Protection ...............................................27
30. Notices ................................................................28
31. Time  ..................................................................28
32. Postponement of Performance ............................................29
33. Brokers ................................................................28
34. No Waiver ..............................................................29
35. Amendments .............................................................29
36. Applicable Law .........................................................29
37. Transfer of the Property................................................29
38. Option to Purchase .....................................................30
39. Option on Additional Space .............................................31
40. Procedure to Require Purchase or Termination of Option .................31
41. Waiver of Counterclaim and Trail by Jury/Attorneys Fees.................31
42. Separability ...........................................................32
43. Corporate Authority ....................................................32
44. Interpretation .........................................................32
       (a)    Captions .....................................................32
       (b)    Gender .......................................................32
       (c)    Covenants ....................................................32
       (d)    Interpretation ...............................................32
45. Landlord's Agreement re: Contract of Sale of the
        Property ...........................................................32
46. Reasonableness of Expenses .............................................33
47. Limits of Landlord's Liability .........................................33
48. Binding Effect..........................................................33
49. Recording...............................................................33

                                      -ii-
<PAGE>

EXHIBITS
--------

EXHIBIT A    Description of Premises

                                     -iii-
<PAGE>

                                 LEASE AGREEMENT

         THIS LEASE is made as of this 22ND day of October, 1996, by and between
Aquila Biopharmaceuticals, Inc. (the "Landlord"), with a business and mailing
address of 365 Plantation Street, Worcester, Massachusetts 01605, and bioMerieux
Vitek, Inc., a Missouri Corporation, (the "Tenant"), with a business and mailing
address of 595 Anglum Drive, Hazelwood, Missouri 63242-2395.

                                   WITNESSETH:

         For and in consideration of the covenants herein contained and upon the
terms and conditions herein set forth, the parties agree as follows:

         1.       INTRODUCTORY PROVISIONS.

                  (a) FUNDAMENTAL LEASE PROVISIONS. Certain Fundamental Lease
provisions are presented in this Section in summary form solely to facilitate
convenient reference by the parties hereto:

                  (1)      LEASED PREMISES

                           3 1/2 Taft Court
                           1500 East Gude Drive
                           Rockville, Maryland

                  (2)      GROSS LEASABLE AREA
                           revised First Amendment

                           2,000 square feet at 3 1/2 Taft Court and
                           38,543 square feet at 1500 E. Gude Drive

                  (3)                              1500 E. GUDE       3 1/2 TAFT
                                                      DRIVE              COURT
                                                   ------------       ----------

                   A.  PROPORTIONATE SHARE -           85%                 8%
                   B.  R.E. PROPORTIONATE SHARE -      85%                34%
                   C.  INSURANCE PROPORTIONATE SHARE - 85%                34%

                  (4)      RENT COMMENCEMENT DATE       October 22, 1996

                  (5)      EXPIRATION DATE -            Tenth Anniversary of the
                                                        Rent Commencement Date

                  (6)      MINIMUM ANNUAL RENT

                           Lease Year 1-3    $466,244.50 per year
                           Lease Year 4-7    $506,787.50 per year
                           Lease Year 8-10   $547,330.50 per year

<PAGE>

                  (7) BASIC MONTHLY RENT

                  Lease Year 1-3                  $38,853.71 per month
                  Lease Year 4-7                  $42,232.29 per month
                  Lease Year 8-10                 $45,610.88 per month

                  (8) TENANT'S USE CLAUSE   -     Manufacturing; general
                                                  office, research and
                                                  development, and uses
                                                  incidental thereto

                  (b) REFERENCES AND CONFLICTS. Each reference in this Lease to
any of the fundamental Lease provisions contained in Section 1(a) shall be
construed to incorporate all of the terms provided for under such provisions,
and such provisions shall be read in conjunction with all other provisions of
this Lease applicable thereto. If there is any conflict between any of the
fundamental Lease provisions set forth in Section 1(a) and any other provisions
of the Lease, the latter shall control.

                  (c) EXHIBITS. The following drawings and special provisions
are attached hereto as exhibits and hereby made a part of this Lease:

         Exhibit A.  Description of Leased Premises

         2.       PREMISES.

                  (a) LEASED PREMISES. Landlord hereby leases to Tenant, and
Tenant hereby rents from Landlord, certain premises (the "Leased Premises")
situated at 1500 East Gude Drive and 3 1/2 Taft Court, Rockville, MD 20850 and
as more fully described on Exhibit A, and as set forth on the floor plan (or
site plan) attached hereto as Exhibit A-1, together with the non-exclusive right
to use the common areas of the Property as more fully described in Section 7
hereof. The Leased Premises shall consist of the agreed square footage of floor
space as specified in Section 1(a)(2).

                  (b) THE PROPERTY. The Leased Premises is (i) a part of
improved real property owned by Landlord which is more fully described as "Lot
5, Block A, in the Red Gate Industrial Park Subdivision as shown on a plat
thereof recorded in Plat Book 102, Plat 11503 among the Land Records of
Montgomery County, Maryland" ("Parcel 1"), and (ii) "Lot numbered Nine (9) in
Block lettered "B" in the subdivision known as "RED GATE INDUSTRIAL PARK" as per
Plat thereof recorded in Plat Book 114 at Plat 13548 among the Land Records of
Montgomery County, Maryland, more commonly known as 1500 East Gude Drive,
Rockville, Maryland 20850 ("Parcel 2"). (Parcel 1 and Parcel 2 are sometimes
collectively referred to herein as the "Property"). Landlord represents and
warrants to Tenant that it is the owner in fee simple of the Property, subject
to certain encumbrances, rights of way, easements, and other matters of record,
none of which interfere with or adversely

                                      -2-
<PAGE>

affect the continued use and occupancy of the Leased Premises as contemplated
herein. Located on Parcel 1 is a portion of the Leased Premises, and a building
known as 3 Taft Court, Rockville, Maryland currently leased to BTRL Contracts
and Services, Inc. pursuant to a lease dated June 30, 1992. The gross leasable
area of the Property is specified in Section 1(a)(3) ("Gross Leasable Area" or
"GLA"). The GLA of the Property shall be used hereinafter for purposes of
Tenant's ",Proportionate Share" (as hereinafter defined)of certain expenses
payable to Landlord as "Additional Rent" (as hereinafter defined). Landlord
reserves the right to modify the GLA of the Property, and shall modify the GLA
of the Property, from time to time during the Lease Term as a result of
construction of new leasable improvements or the demolition of existing leasable
improvements on the Property. Landlord's right to modify the GLA of the Property
shall not be construed to provide Landlord with any right to modify the floor
plan of the Leased Premises, or to deprive Tenant of the reasonable use of any
portion of the parking areas or other common areas allocated to it.

                  (c) TENANT'S PROPORTIONATE SHARE. Tenant's Proportionate Share
of certain expenses hereinafter made payable to Landlord as Additional Rent is
specified in Section 1 (a)(4). Said computation is based upon the ratio of the
total area of floor space in the Leased Premises to the GLA of the Property. The
Proportionate Share shall be modified during the Lease Term in the event that
the GLA of the Property is modified as described in Section 2 (b) above.

         3.       TERM AND ACCEPTANCE BY TENANT.

                  (a) LEASE TERM. The term of this Lease (sometimes herein
called the "Lease Term") shall begin as of the date specified in Section 1(a)(5)
("Rent Commencement Date") and, unless sooner terminated as herein provided,
continue thereafter through the date specified in Section 1(a)(6) ("Expiration
Date"). The period commencing with the Rent Commencement Date and ending on the
last day of the TWELFTH (12TH) FULL CALENDAR MONTH thereafter shall constitute
the first "LEASE YEAR" as such term is used herein. Each successive FULL twelve
(12) month period during the Lease Term shall constitute a "Lease Year".

                  (b) RENEWAL OPTION. Tenant may extend the original term of
this Lease for two (2) consecutive additional terms of ten (10) Lease Years each
by giving to Landlord notice of each such election at least one hundred eighty
(180) days prior to the expiration of the original term or then renewal term
hereof, as applicable; provided, however, that Tenant shall not have such right
to extend if it shall then be in default under the terms of this Lease (at the
time of election) or if this Lease shall have earlier expired or terminated, and
that there shall only be two (2) such renewal terms. The Minimum Annual Rent
payable during each renewal term shall be a sum equal to the fair rental value
(the "Fair Rental Value") of the Leased Premises on the date which

                                      -3-
<PAGE>

is one hundred eighty (180) days prior to the commencement date of said renewal
term (such Fair Rental Value being determined by agreement between Landlord and
Tenant), but in no event shall such minimum Annual Rent be less than the Minimum
Annual Rent payable by Tenant for the last Lease Year of the prior term or more
than one hundred twenty-five percent (125%) of the Minimum Annual Rent payable
by Tenant for the last Lease Year of the prior term.

                      If, at least five (5) months prior to the expiration of
the then current term of this Lease, Landlord and Tenant are unable to agree
upon said Fair Rental Value for the next renewal term, either party may serve a
written notice on the other party nominating and appointing an appraiser who
shall have at least five years experience in real estate in the Rockville,
Maryland area and in the case of the third appraiser shall not have acted in any
manner for either Landlord or Tenant within four years of the appointment, and
within fifteen (15) days thereafter the other party shall appoint an appraiser.
Upon the appointment of the two appraisers as hereinabove provided, said
appraisers shall forthwith, and within fifteen (15) days after the appointment
of the second appraiser, and before exchanging views to the question at issue,
appoint in writing a third appraiser and give written notice of such appointment
to each of the parties. In the event the two appraisers shall fail to appoint or
agree upon third appraiser within said fifteen (15) day period, a third
appraiser shall be selected by the parties themselves if they so agree upon such
third appraiser within a further period of ten (10) days. If any appraiser shall
not be appointed or agreed upon within the time herein provided, then either
party may apply to the appropriate Court of the State of Maryland having
jurisdiction for appointment of such appraiser. Said appraisers shall be sworn
faithfully and fairly to determine the Fair Rental value. The three appraisers
shall afford to the parties a hearing and the right to submit evidence, with the
privilege of cross-examination, on the question at issue and shall, with all
possible speed, make their determination in writing and shall give notice to the
parties of such determination. The concurring determination of any two of said
three appraisers shall be binding upon the parties, or, in case no two of the
three appraisers shall render a concurring determination, then the determination
of the third appraiser appointed shall be binding upon the parties. The fees and
expenses of the appraisers shall be divided equally between the parties.

                      If Tenant shall have exercised an option to extend the
term of this Lease within the time period herein provided, this Lease shall be
deemed extended upon all of the then executory terms, covenants and conditions
contained herein except that the Minimum Annual Rent payable during such
extended term shall be as set forth above in this paragraph. Time shall be of
the essence as to any notice which may be given by Tenant under this paragraph.

                                      -4-
<PAGE>

                  (c) ACCEPTANCE OF LEASED PREMISES. Tenant accepts possession
of the Leased Premises in "as is" condition, Tenant expressly acknowledges and
agrees that Landlord has made no representations or warranties with respect to
the Leased Premises, and that no promises to alter, repair or improve the Leased
Premises or the Property have been made by Landlord or its agents or employees,
unless specifically set forth herein. Notwithstanding the foregoing, Landlord
agrees that on the commencement date of the Lease the leaks in the roof and/or
surrounding areas of the buildings on the property situated at 1500 E. Gude
Drive and 3 1/2 (Taft Court shall be repaired, or that Landlord shall continue
to use diligent efforts to remove the cause of any continuing or new leaks.

                  (d) PERMITS. Tenant shall be responsible for obtaining any
permits or licenses necessary, because of any change in Tenant's use of the
Leased Premises from that use contemplated herein, for its lawful occupancy of
the Leased Premises. This requirement shall not relieve Tenant of its liability
for the payment of Minimum Annual Rent and Additional Rent, and the performance
of all other obligations contained herein, from and after the Rent Commencement
Date, in the event that all of said approvals, permits and licenses have not
been acquired prior thereto.

         4.       RENT.

                  (a) MINIMUM ANNUAL RENT. The Minimum Annual Rent reserved
hereunder in Section 1(a) (7) shall be payable by Tenant to Landlord during each
Lease Year of the Lease Term in equal monthly installments of Basic Monthly Rent
in the amounts set forth in Section 1(a) (8), due in advance, without notice or
demand, and without set-off, deduction, recoupment or abatement of any kind
except as otherwise set forth herein, on the Rent Commencement Date and the
first (1st) day of each and every calendar month thereafter during the Lease
Term. In the event that the Rent Commencement Date occurs on a day other than
the first day of a calendar month or the Lease Term ends on a day other than the
last day of a calendar month, then the Basic Monthly Rent or Additional Rent for
such partial month(s) shall be computed on a per diem basis by dividing the
Basic Monthly Rent or Additional Rent by thirty (30) and multiplying it by the
number of days in the partial calendar month. Rent shall be paid to landlord, or
to such other person(s), or at such other address as Landlord may designate to
Tenant from time to time.

                  (b) ADDITIONAL RENT.

                      (i) GENERAL. Whenever it is provided by the terms of this
Lease that Tenant is required to make any payment to Landlord other than a
payment of Minimum Annual Rent, such payment shall be deemed to be a payment of
additional rent ("Additional Rent"). Unless otherwise expressly specified
herein, Additional Rent shall be paid by Tenant with the next installment of
Basic

                                      -5-
<PAGE>

Monthly Rent thereafter falling due. Additional Rent shall include, but not be
limited to.

                      (ii) REAL ESTATE TAXES. Commencing upon the first day of
the first month of the Lease, and thereafter on the first day of each calendar
month throughout the Lease Term, Tenant shall pay to Landlord, without notice or
demand therefor (other than the annual notice of Landlord's estimate of Tenant's
R.E. proportionate Share of the Real Estate Taxes and a copy of the tax bills as
described in the following paragraph of this section), and without any deduction
whatsoever, one-twelfth (1/12) of its R.E. Proportionate Share of Landlord's
good faith estimate of the Real Estate Taxes to be incurred by Landlord on the
Property during that tax year (prorated, if necessary, if the remainder of the
Lease Term constitutes less than the full tax year). Tenant's obligation to pay
its R.E. Proportionate Share of the Real Estate Taxes incurred during the Lease
Term shall survive the expiration or other termination of the Lease.

         The term "Real Estate Taxes" shall mean all taxes and assessments,
general and special, ordinary and extraordinary, foreseen and unforeseen, now or
hereafter assessed, levied or imposed upon the Property, including both the land
and the improvements which are built thereon, including, without limitation,
front foot benefit charges and adequate public facility costs and assessments,
together with (i) any tax, assessment, or other imposition in the nature of a
real estate tax, (ii) any ad valorem tax on rent or any tax on income if imposed
in lieu of or in addition to real estate taxes and assessments, and (iii) any
taxes and assessments Which may hereafter be substituted for real estate taxes,
including by way of illustration only, any tax, assessment or other imposition
(whether a business rental or other tax) now or hereafter levied upon Landlord
for a tenant's use or occupancy of or conduct of business on the Property, or a
tenant's improvements to or furniture, fixtures or equipment on the Property.
Real Estate Taxes shall also included all reasonable costs incurred by Landlord
in contesting the validity or amount of any such taxes. Real Estate Taxes shall
not include transfer, inheritance, capital stock or income taxes or other
similar personal tax of Landlord, nor any late charges, penalties or interest,
incurred due to untimely payments by Landlord in connection with said tax.

         Within fifteen (15) days after Landlord's receipt from the taxing
authority of the Real Estate Tax bills for the fiscal 1997 tax year and for each
tax year thereafter during the Lease Term, Landlord shall deliver to Tenant a
copy of such tax bills, together with a statement showing Tenant's R.E.
Proportionate Share of the actual Real Estate Taxes due for said tax year and
the amount of payments made by Tenant based upon the estimate thereof. Tenant
shall pay Landlord, within thirty (30) days of Tenant's receipt of such
statement, Tenant's R.E. Proportionate Share of the excess, if any, of the Real
Estate Taxes for such tax Year over the estimated costs thereof. If the amount
paid by

                                      -6-
<PAGE>

Tenant as Tenant's R.E. Proportionate Share of the estimated Real Estate Taxes
for such tax year exceeded Tenant's R.E. proportionate Share of actual Real
Estate Taxes for such tax year, the excess shall be credited toward payment of
the next installment of Basic Monthly Rent to be paid by Tenant after Tenant
receives said statement from Landlord. If the amount paid by Tenant for the last
tax year of the Lease Term exceeds Tenant's R.E. Proportionate Share of actual
Real Estate Taxes for such tax year, Landlord shall pay Tenant the excess amount
within thirty (30) days after Landlord's submission to Tenant of the aforesaid
statement for such tax year.

         Upon Tenant's written request, Landlord will contest, at Tenant's
expense, the validity or amount of any such Real Estate Tax. Tenant shall be
entitled to its R.E. Proportionate Share of any refund or reduction.

         Tenant shall receive a credit for the amount of any expenses it paid
which resulted in a refund or reduction applicable to the rest of the Property.

         Landlord shall deposit and thereafter hold in escrow, until
disbursement, the funds received from Tenant pursuant to this section in an
interest bearing, federally insured account. All interest earned on said account
shall be credited to Tenant and shall be used in the adjustments to Tenant's
payments made hereunder from time to time during the lease Term so that Landlord
collects only such monies as are necessary to pay Tenant's R.E. Proportionate
Share of said Real Estate Taxes.

         In addition to Tenant's obligation for the payment of its R.E.
Proportionate Share of the Real Estate Taxes, Tenant shall be liable for, and
shall pay before delinquency, all taxes levied against any personal property or
trade fixtures placed by Tenant in or about the Leased Premises.

                      (iii) INSURANCE. Commencing upon the Rent Commencement
Date and thereafter throughout the Lease Term, Tenant shall pay to Landlord
without notice or demand therefor and without any deduction whatsoever, its
Insurance Proportionate Share of the premium cost of the casualty insurance,
liability insurance, rent loss insurance, and other reasonable and necessary
form of insurance carried by Landlord with respect to the Property ("Insurance
Cost") during any policy year; provided, however, that if the adjacent building
on Parcel 1 is demolished during the Lease Term, then commencing upon such
demolition and for so long as the Leased Premises constitutes one hundred
percent (100%) of the leasable improvements on the Property, Tenant shall be
obligated to pay one hundred percent (100%) of the Insurance Cost.

         Not less than ten (10) days before the Rent Commencement Date, Landlord
shall deliver to Tenant a written statement, with supportive documentation of
Landlord's estimate of the amount of the Insurance Cost for the then current
policy year, and Tenant's

                                      -7-
<PAGE>

Insurance Proportionate Share of such Insurance Cost. On the Rent commencement
Date, and on the first day of each month thereafter throughout the Lease Term,
Tenant shall pay one-twelfth (1/12) of Tenant's Insurance Proportionate Share of
Landlord's estimate, with supportive documentation of the Insurance Cost for the
then-current policy year, as shown on Landlord's estimate. Landlord shall submit
its estimate of the Insurance Cost for the forthcoming policy year and Tenant's
Insurance Proportionate Share thereof at the Commencement of each such policy
year, and Tenant's monthly payments made after its receipt of such estimate
shall be in the amount of one-twelfth (1/12) of the amount of Tenant's Insurance
Proportionate Share of Insurance Cost as shown on such estimate. Landlord may
revise its estimate of the Insurance Cost at any time during a policy year by
notice to Tenant, setting forth such revised estimate, with supportive
documentation and Tenant's Insurance Proportionate Share thereof. In such event,
all monthly payments made by Tenant after such notice shall be in an amount
calculated on the basis of such revised estimate. Tenant shall, in all cases,
continue to make monthly payments of Insurance Cost based on the last estimate
received from Landlord until it receives a revised or updated estimate.

         After the end of each policy year, Landlord will as soon as practicable
submit to Tenant a statement of the actual Insurance Cost for such policy year
and Tenant's Insurance Proportionate Share thereof. Landlord shall cause its
insurance carrier, whenever practical, to issue policies of insurance covering
the Leased Premises which are separate and apart from all other properties owned
by Landlord, in which event Tenant's Proportionate Share of Insurance Cost shall
be the full cost payable pursuant to said separate policy, where such separate
policies cannot be issued practically, Landlord shall cause its insurance
carrier to provide a written statement identifying the manner in which all
premiums paid by Landlord are allocated to reflect the portion thereof
attributable to the insurance carried on the Leased Premises and the portion
thereof attributable to the insurance carried on other properties owned by
Landlord. Tenant shall pay Landlord, within thirty (30 days of Tenant's receipt
of such statement, Tenant's Insurance Proportionate Share of the excess, if any,
of Insurance Cost for such policy year over the projected Insurance Cost. If the
amount paid by Tenant as Tenant's Insurance Proportionate Share of the estimated
Insurance Cost for such policy year exceeded Tenant's Insurance Proportionate
Share of actual Insurance Cost for such policy year, the excess shall be
credited toward payment of the next installment of Basic Monthly Rent to be paid
by Tenant after Tenant receives said statement from Landlord. If the amount paid
by Tenant for the last policy year of the Lease Term exceeds Tenant's Insurance
Proportionate Share of actual Insurance Cost for such year, Landlord shall pay
Tenant the excess amount within thirty (30) days after Landlord's submission to
Tenant of the aforesaid Insurance Cost statement for such policy year.

                                      -8-
<PAGE>

         Landlord Shall deposit and thereafter hold in escrow, until
disbursement, the funds received from Tenant pursuant to this section in an
interest bearing, federally insured account. All interest earned on said account
shall be credited to Tenant and shall be used in the adjustments to Tenant's
payments made hereunder from time to time during the Lease Term so that Landlord
collects only such monies an are necessary to pay Tenant's Insurance
Proportionate Share of said Insurance Cost.

         Landlord agrees that, at all times during the Lease Term, it shall
carry casualty insurance and liability insurance in such form and in such
amounts which are consistent with good business practice and generally
comparable to the coverage of casualty insurance policies and liability
insurance policies carried by landlord's owning commercial buildings located in
Montgomery County, Maryland that are similar to the Leased Premises.

                      (iv) UTILITY EXPENSES NOT SEPARATELY METERED.

                           (aa) Throughout Lease Term, Tenant agrees to pay to
Landlord, as Additional Rent, Tenant's Proportionate Share of all water usage
charges, exterior electric lighting charges, and any other utility charges
("Shared charges") not separately metered (and only for so long as each is not
separately metered) for each of the Leased Premises and the common areas of the
Property.

                           (bb) Upon receipt of each billing for Shared charges,
Landlord will as soon as practicable submit to Tenant a statement of Shared
Charges incurred for the preceding billing period. Tenant shall pay Landlord,
within thirty (30) days of Tenant's receipt of such statement, Tenant's
Proportionate Share of Shared Charges.

                      (v) LANDLORD'S ENFORCEMENT COSTS. Additional Rent shall
include any and all expenses incurred by Landlord, including reasonable
attorneys' fees, for the collection of monies due from Tenant and the
enforcement of Tenant's obligations under the provisions of this Lease. In the
event Minimum Annual Rent or Additional Rent is not paid within fifteen (15)
business days of its due date, Landlord, at its sole option, may assess a late
charge equal to two percent (2%) of the amount of the delinquent Basic Monthly
Rent and Additional Rent as compensation for the additional administrative costs
incurred by Landlord as a result of such late payment.

                      (c) PAYMENT OF RENT. Any Minimum Annual Rent or Additional
Rent which is not paid within ten (10) business days after the same is due shall
bear interest ("Penalty Rate") at one percentage (1%) point above the prime rate
of interest published in the Wall Street Journal or a successor or similar
financial publication existing from time to time and adjusted each day the prime
rate is redetermined to reflect the change in said prime rate of interest, from
the due data until the date received by

                                      -9-
<PAGE>

Landlord. Any payments of Minimum Annual Rent or Additional Rent by Tenant or
acceptance by Landlord of a lesser amount than shall be due from Tenant to
Landlord shall be treated as a payment on account. The acceptance by Landlord of
a check for a lesser amount with an endorsement or statement thereon, or upon
any letter accompanying such check, that such lesser amount is payment in full,
shall be given no affect, and Landlord may accept such check without prejudice
to any other rights or remedies which Landlord may have against Tenant. If
Landlord receives from Tenant two (2) returned or "bounced" checks in any one
Lease Year, Landlord may require all future Rent by cashier's or certified
check.

         5.       USE.

                  (a) USE. Tenant shall use the Leased Premises for the purposes
specified in Section 1(a) 9), and for no other purpose.

                  (b) COMPLIANCE WITH LAWS, FIRE INSURANCE, CONDITION OF
LEASED PREMISES. Tenant shall not do, or permit anything to be done in the
Leased Premises or on the Property, or bring or keep anything therein, which
will in any way invalidate or conflict with fire insurance policies on the
Property, including, but not limited to all improvements, the Property
fixtures and personal property kept therein, or obstruct or interfere with
the rights of the Landlord or of other tenants of the Property, or in any
other way injure or annoy Landlord or such other tenants, or subject Landlord
to any liability for injury to persons or damage to property, or interfere
with the good order of the Property as determined by Landlord in its
reasonable discretion. Tenant shall refrain or discontinue said use
immediately upon receipt of written notice from Landlord requiring such
action. Tenant, at its expense, shall comply with all present and future
laws, rules or regulations of any federal, state or municipal authority, or
the Maryland Fire Underwriters Rating Bureau, or with any notice from any
public officer pursuant to law pertaining to Tenant's occupancy or use of the
Leased Premises, whether such notice shall be served on Landlord or Tenant
provided Tenant shall have no obligation to make any structural changes to
the Leased Premises. Tenant agrees to indemnify, defend, and hold Landlord
harmless from any injury to persons or damage, to property occurring in or
around the Leased Premises, occasioned by any act or omission of invitees or
licensees. Tenant agrees that any increases of fire insurance premiums on the
Leased Premises or contents caused by the occupancy of Tenant and any
expenses or costs incurred in consequence of negligence or carelessness or
the willful action of Tenant, Tenant's employees, agents, contractors,
servants, invitees, or licensees shall be deemed Additional Rent and paid by
Tenant to Landlord as they accrue.

                                      -10-
<PAGE>

         6.       COMMON AREAS.

                  (a) COMMON AREAS DEFINED. In this Lease, "common areas" means
all areas, facilities and improvements provided, from time to time, on the
Property for the mutual convenience and use of all tenants or other occupants of
the Leased Premises and the adjacent building, their respective agents,
employees, and invitees, and Shall include, if provided, but are not limited to,
parking areas and facilities, access roads, driveways, retaining walls,
sidewalks, walkways, landscaped areas, and exterior lighting facilities.

                  (b) LANDLORD'S CONTROL. Landlord shall, as between Landlord
and Tenant, at all times during the Lease Term have the sole and exclusive
control, management and direction of the common areas, and may, at any time and
from time to time during the Lease Term, exclude and restrain any person from
use or occupancy thereof, excepting, however, Tenant and other tenants of
Landlord and bona fide invitees of either who make use of said areas in
accordance with the rules and regulations established by Landlord from time to
time with respect thereto. The rights of Tenant in and to the common areas shall
at all times be subject to the rights of others to use the same in common with
Tenant, and it shall be the duty of Tenant to keep all of said areas free and
clear of any obstructions created or permitted by Tenant or resulting from
Tenant's operation. Landlord may at any time and from time to time (i) close all
or any portion of the common areas to make repairs or changes, (ii) close all or
any portion of the common areas to such extent as may, in the opinion of
Landlord, be necessary to prevent a dedication thereof or the accrual of any
rights to any person or to the public therein, and (iii) do and perform such
other acts in and to said areas as, in the exercise of good business judgment,
Landlord shall determine to be advisable with a view to the improvement of the
convenience and use thereof by tenants, their employees, agents, and invitees,
provided Landlord shall do so with a minimum of interference with Tenant's use
and enjoyment thereof. Landlord shall at all times have the right and privilege
of determining the nature and extent of the common areas, and of making such
changes, rearrangements additions or reductions therein and thereto from time to
time which in its opinion are deemed to be desirable and for the best interest
of all persons using the common areas or which are as a result of, any federal,
state or local environmental protection or other law, rule, regulation,
guideline or order, provided Landlord shall do so with a minimum of interference
with Tenant's use and enjoyment thereof. The purpose of the site plans attached
hereto as Exhibit A is to show the approximate locational relationship of the
Leased Premises to the adjacent building and to the common areas as of the Rent
Commencement Date. Nothing described in Exhibit A shall limit or prevent
Landlord from affecting any change or alteration to the Property as described in
this paragraph, provided Landlord shall do so with a minimum of interference
with Tenant's use and enjoyment thereof. Nothing contained in this Section shall
give Landlord the right to impose

                                      -11-
<PAGE>

restrictions on the use and enjoyment of the common areas by Tenant, or to make
modifications to the common areas, in a way to cause Tenant to be unable no use
the Leased Premises and the common areas in a reasonable manner for the purposes
originally contemplated by this Lease.

                  (c) PARKING SPACES. During the Lease Term, Tenant shall have
the exclusive right to the use of [parking spaces] at no additional cost.

         7. RULES AND REGULATIONS. Tenant agrees to comply with and observe any
reasonable rules and regulations promulgated by Landlord, which may be
supplemented or amended from time to time by Landlord. Tenant's failure to keep
and observe said rules and regulations shall constitute a breach of the terms of
this Lease in the same manner as if the same were contained herein as covenants.

         8. UTILITIES. Tenant shall be solely responsible for and shall promptly
pay any and all utility charges including but not limited to electricity, water,
fuel, gas, and telephone (including equipment and installation charges) used in,
consumed at, or supplied to the Leased Premises. Tenant shall immediately
transfer all separately metered utility accounts for the Leased Premises into
its own name on the Rent Commencement Date. Tenant shall pay to Landlord, as
Additional Rent, its Proportionate Share of any and all bills for utility
charges which are not separately metered in the or described in Section 4
(b)(iv) hereof.

         9. LANDLORD'S RIGHT OF ENTRY. Landlord, and its agents, shall have the
right, upon prior notice to Tenant and during reasonable business hours during
the Lease Term (except in the case of an emergency involving damage to person or
property), to enter upon the Leased Premises to examine the same, or to make
such repairs, alterations or improvements, as Landlord may deem necessary or
proper, or to remove any alteration or improvement which is in violation of the
provisions of this Lease, provided, however, Landlord shall not adversely
interfere with Tenant's business operations in a material manner. Landlord
reserves the right to show the Leased Premises to prospective tenants or brokers
during the last ninety (90) days of the Lease Term, and to show the Leased
Premises to prospective purchasers and lenders at all reasonable times, provided
that reasonable prior verbal notice is given to Tenant in each case and that
Tenant's use and occupancy of the Leased Premises shall not be materially
inconvenienced by any such action of Landlord.

         10.      MAINTENANCE AND REPAIR.

                  (a) TENANT'S RESPONSIBILITY. Tenant shall maintain the Leased
Premises in substantially the same good order and condition as it is on the
commencement of the Lease Term and shall return the Leased Premises to Landlord
in such condition at the Expiration Date or at the earlier termination of this
Lease,

                                      -12-
<PAGE>

ordinary wear and tear excepted. Except as obligations to repair are expressly
delegated to Landlord as described in Section 10(b) below, Tenant shall be
responsible for the full cost of all maintenance and repairs of (i) the Leased
Premises, including but not limited to the doors, door jambs, windows, window
casings and sills, screens, floor coverings, walls (excluding load bearing
structures), and ceilings located in the Leased Premises and all pipes, gutters,
downspouts, wires, conduits and other equipment and fixtures located in the
Leased Premises. Tenant, at its expense, shall perform routine maintenance and
repair and replacement of the plumbing, electrical, heating, ventilating and
air-conditioning systems, and all other systems and equipment, serving the
Leased Premises. Tenant will throughout the Lease Term obtain and keep in force
a maintenance contract with a qualified service company to regularly inspect and
perform maintenance services to the heating, ventilating and air-conditioning
system serving the Leased Premises. Tenant, at its expense, shall furnish
Landlord with a copy of said maintenance contract, and of renewals or
replacements thereof, promptly after the effective date thereof. All repairs and
maintenance required to be performed by Tenant at the Leased Premises shall be
made or performed within a reasonable period of time upon the occurrence of the
necessity therefor, and shall be made or performed in a workmanlike or, using
first class materials, by a contractor duly licensed in the State of Maryland,
and shall be made or performed in accordance with (i) all applicable federal,
state and county governmental codes and regulations, and (ii) insurance
requirements. Tenant shall also be responsible for keeping all sidewalks and
parking areas on that portion of the Property situated at 1500 E. Gude Drive
free and clear of dirt, trash, debris, ice, snow, and any other obstructions;
provided, however, that Landlord shall upon request promptly reimburse Tenant
for the cost of any such services less Tenant's Proportionate Share of such
services. Tenant shall be responsible for Tenant's Proportionate Share of such
services as pertain to 3 1/2 Taft Court which shall be performed by the tenant
at 3 Taft Court. Tenant shall keep its trash and garbage in enclosed containers
in a trash holding area within the Leased Premises, and shall perform regular
trash removal from such trash holding area. Tenant shall also be responsible for
the performance of regular, periodic pest control services at the Leased
Premises. All glass, both exterior and interior, shall be maintained in the
Leased Premises at the sole risk of Tenant, and Tenant agrees to replace any
glass promptly at its sole expense in the event of breakage.

                  (b) LANDLORD'S RESPONSIBILITY. Except for any structural
alterations or improvements made by Tenant, Landlord shall maintain in good
order and repair the ROOF and the structural portions of the foundation, floors,
stairwells, exterior walls, columns and other load bearing elements of the
Leased Premises.

                                      -13-
<PAGE>

         11.      ALTERATIONS OR IMPROVEMENTS BY TENANT. Except for incidental
painting and decoration of the interior of the Leased Premises and other minor
alterations and improvements which do not affect the structure or utility
systems of the Leased Premises, Tenant shall not make any alterations,
additions, or improvements, structural or otherwise costing in excess of $50,000
(except Tenant may make non-structural alterations in Lease Year one costing up
to $150,000 without Landlord's consent) (collectively, "Alterations") in, on or
to the Leased Premises, without the prior written consent of Landlord, which
consent shall not be unreasonably withheld or delayed. In connection with
Landlord's review of such proposed alterations or improvements prior to giving
its consent thereto, Landlord shall have the right to require that Tenant supply
plans, specifications, working drawings and similar documents in reasonable
detail which show the scope of work to be performed within the Leased Premises.
Landlord's approval of the plans, specifications and working drawings for
Tenant's alterations and improvements shall create no liability on the part of
Landlord for their completeness, design sufficiency, or compliance with all
laws, rules, regulations or governmental agencies or authorities. Any
contractors employed by Tenant to perform Tenant's work (i) shall be qualified
to perform such work and licensed in the State of Maryland and (ii) shall
maintain any insurance which may be reasonably required by Landlord, and (iii)
shall be bonded or otherwise reasonably satisfactory to Landlord. Subject to
paragraph 5 (b)hereof, Tenant will defend, indemnify and hold Landlord harmless
from and against any and all expenses, liens, claims or damages, including
attorneys' fees, for injury to person or property which may or might arise,
directly or indirectly, by reason of the making of any Alterations. If any
Alterations are effected without the prior written consent of Landlord, Landlord
may remove or correct the same and Tenant shall be liable for any and all
expenses of this work. All rights given to Landlord herein shall be in addition
to any other right or remedy of Landlord contained in this Lease. Tenant shall
be obligated to make any and all Alterations and other improvements to the
Leased Premises required by applicable federal, state and local law, in
connection with the use of the Leased Premises by Tenant during the Leased Term.
Tenant hereby agrees that all Alterations made in, to, or on the Leased Premises
shall, unless otherwise provided by written agreement or by the provisions of
Section 12 below, be the property of Landlord and shall remain upon and be
surrendered with the Leased Premises on the Expiration Date or other termination
of this Lease.

         12.      SURRENDER. Upon the Expiration Date or other termination of
the Lease Terms, Tenant shall quit and surrender the Leased Premises to the
Landlord in good order and condition, ordinary wear and tear excepted, and
Tenant shall remove all of its personal property from the Leased Premises on
or before the Expiration Date or other termination of this Lese[sic].
Tenant's obligation to observe or perform the covenants described in this
Section 12 shall survive the expiration or other termination of this Lease.
If Tenant does not remove Tenant's furniture, trade fixtures and all other
items of personal property of every kind

                                      -14-
<PAGE>

and description from the Leased Premises as specified herein, then Landlord
shall be permitted to remove, dispose or otherwise discard such property without
further payment or credit by Landlord to Tenant. Notwithstanding anything to the
contrary contained in this Lease, Tenant shall have the right and the
obligation, at the end of the Lease Term, to remove all built-in desks,
cabinets, basins, emergency showers and other pieces of equipment which are
affixed to the Leased Premises by Tenant. In connection with the removal of said
equipment, Tenant shall be obligated to stub pipes; bundle and cap wires; close
ducts; repair and replace (as appropriate) flooring coverings, repair, replace,
finish and repaint (as appropriate) walls, and perform all other acts which are
necessary for the Leased Premises to be returned to Landlord in same good order
and Condition as exists of the Rent Commencement Date.

         13.      TENANT HOLDING OVER. If Tenant holds possession of the Leased
Premises after the Expiration Date or other termination of this Lease, Landlord
shall have the option, exercisable in writing within thirty (30) days after the
date if termination as aforesaid, to treat Tenant as a trespasser, or as a
tenant by the month. If the Landlord fails to made such election then the Tenant
shall be deemed a tenant by the month, commencing with the first day after the
termination of the Lease at one hundred fifty percent (150%) of the Basic
Monthly Rent paid during the last month of the Lease Term, and upon all the
other terms of this Lease, including the provisions of this Section. Said
holdover term shall terminate upon thirty (30) days notice from one party to the
other. Nothing contained herein shall be construed within said thirty (30) days
after the date of Lease termination as aforesaid as a consent by Landlord to the
occupancy or possession of the Leased Premises by Tenant after the termination
of the Lease, and Landlord, upon said termination, if Landlord elects to treat
Tenant as a trespasser, shall be entitled to the benefit of all general or
public laws relating to the speedy recovery of the possession of land and
tenements held over by Tenant, whether now or hereafter in force and effect. If
Tenant fails to surrender the Leased Premises upon the expiration or other
termination of this Lease despite demand to do so by Landlord, Tenant shall
indemnify, defend, and hold Landlord harmless from all injury, loss, claims,
expenses and liability including without limitation, any claim made by any
succeeding tenant and any attorneys' fees, founded on or resulting from such
failure to surrender.

         14.      ASSIGNMENT AND SUBLETTING.

                  (a) ASSIGNMENT BY TENANT. Tenant shall not assign, mortgage or
encumber this Lease, or any right hereunder, nor sublet the Leased Premises or
any part thereof, nor permit the Leased Premises to be used by others without
the prior written consent of Landlord, which consent shall not be unreasonably
withheld or delayed; provided that any such consent may be conditional upon
Tenant's agreement that, any monthly rent or

                                      -15-
<PAGE>

other payment accruing to Tenant as the result of any such assignment, transfer
or sublease, including any lump sum or periodic payment in any manner relating
to such assignment, transfer or sublease, which is in excess of the Minimum
Annual Rent and Additional Rent then payable by Tenant under the Lease shall be
paid by Tenant to Landlord monthly as Additional Rent, excluding any reasonable
expenses incurred by Tenant in connection with such assignment or subletting,
e.g. legal fees and brokers' commissions. Except as set forth herein, without
prior written consent of Landlord, this Lease and the interest of Tenant, or any
assignee of Tenant, shall not pass by operation of law, nor shall it be subject
to garnishment or sale under execution in any suit or proceeding which may be
brought against or by Tenant, or any assignee of Tenant. No assignment of this
Lease, sublease of all or any portion of the Leased Premises, or collection of
rent from an assignee or subtenant (whether or not permitted by Landlord) shall
relieve Tenant of its obligations hereunder. Any reasonable costs and expenses,
including reasonable attorneys' fees incurred by Landlord in connection with any
proposed or purported assignment, transfer or sublease shall be borne by Tenant
and shall be payable to Landlord as Additional Rent within five (5) days of
demand therefor.

                  Notwithstanding anything herein to the contrary, Tenant shall
have the right, without Landlord's prior written consent, to assign this Lease
or sublet the Leased Premises to any parent corporation of Tenant, or to any
subsidiary of any parent corporation of Tenant, subject to the following express
conditions:

                  (i)      No such assignment or sublease shall be deemed to
                           release Tenant from continuing liability for all of
                           Tenant's covenants and obligations under this Lease;
                           and

                  (ii)     Any assignee or subtenant must expressly assume in
                           writing all of the covenants and obligations of
                           Tenant under this Lease, joint and severally with
                           Tenant.

                  Further, the provisions of this Section shall not apply to an
assignment of this Lease (or to a sale or transfer of Tenant's stock) resulting
from a merger, consolidation, corporate reorganization (other than pursuant to
the bankruptcy laws), sale of the assets or other transfer of stock of Tenant:

                  Further, any issuance by Tenant of its capital stock in a
public offering which is effected in compliance with the registration
requirements of the Securities Act of 1933, as amended, and the rules and
regulations thereunder, shall not be deemed to be a change in control or an
assignment of this Lease requiring Landlord's consent.

                                      -16-
<PAGE>

                  (b) ASSIGNMENT BY LANDLORD. It is expressly understood and
agreed that this Lease and all rights of Landlord hereunder shall be fully and
freely assignable by Landlord without notice to, or consent of, Tenant. In the
event of the transfer and assignment by Landlord of its interest in this Lease,
Landlord shall thereby be released from any responsibility for the performance
of obligations thereafter accruing hereunder, and Tenant agrees to look solely
to such successor in interest of the Landlord for performance of such
obligations. Nothing contained herein shall prevent Tenant from looking to
Landlord for the performance of obligations of which Landlord has actual
knowledge and which predate the effective date of the transfer and assignment by
Landlord of its interest in this Lease. The term "Landlord" as used in this
Lease shall mean the owner of the Leased Premises, at the time in question. In
the event of a transfer (whether voluntary or involuntary) by such owner of its
interest in the Leased Premises, such owner shall thereupon be released and
discharged from all covenants and obligations of the Lease thereafter accruing,
but such covenants and obligations shall be binding during the Lease Term upon
each new owner for the duration of such Owner's ownership.

         15.      BANKRUPTCY.

                  (a) The following shall be Events of Bankruptcy under this
Lease: (1) Tenant becoming insolvent, as that term is defined in Title 11 of the
United States Code :(the "Bankruptcy Code"), or under the insolvency laws of any
state, district, commonwealth or territory of the United States (the "Insolvency
Laws"); (2) the appointment of a receiver or custodian for any or all of
Tenant's property or assets, or the institution of a foreclosure action upon any
of Tenant's real or personal property; (3) the filing of a voluntary petition
under the provisions of the Bankruptcy Code or Insolvency Laws by Tenant; (4)
the filing of an involuntary petition against Tenant as the subject debtor under
the Bankruptcy Code or Insolvency Laws, which either (A) is not dismissed within
one hundred twenty (120) days of the date of filing, or (B) results in the
issuance of an order for relief against the debtor; or (5) Tenant's making or
consenting to an assignment for the benefit of creditors or a common law
composition of creditors.

                  (b) Upon occurrence of an Event of Bankruptcy, Landlord shall
have all rights and remedies available to Landlord pursuant to Section 17;
provided, however, that while a case in which Tenant is the subject debtor under
the Bankruptcy Code is pending, Landlord shall not exercise its rights and
remedies pursuant to Section 19 so long as (1) the Bankruptcy Code prohibits the
exercise of such rights and remedies, and (2) Tenant or its Trustee in
Bankruptcy (hereinafter referred to as "Trustee") (I) cures all defaults under
this Lease, (ii) compensates Landlord for monetary damages incurred as a result
of such defaults, (iii) provides adequate assurance of future performance on the
part of Tenant as debtor in possession or on the part of the assignee

                                      -17-
<PAGE>

tenant, and (iv) complies with all other requirements of the Bankruptcy Code and
this Lease.

         16.      DEFAULT. Each of the following shall be deemed a default by
Tenant and a material breach of this Lease:

                  (a)      An Event of Bankruptcy as defined in Section 15;

                  (b)      An assignment or encumbrance of Tenant's interest in
                           this Lease or the Leased Premises or a subletting of
                           any part of the Leased Premises in violation of
                           Section 14;

                  (c)      A failure by Tenant to make any payment of Minimum
                           Annual Rent or Additional Rent within five (5) days
                           of receipt of written notice that such payment was
                           not received on its due date (provided that Landlord
                           shall not be obligated to provide Tenant with such
                           written notice more than twice during any twelve
                           month period during the lease Term, and after receipt
                           of such second notice, Tenant shall be deemed in
                           default, without further notice, if any such payment
                           is not received by Landlord on its due date);

                  (d)      Abandonment of the Leased Premises for more than
                           thirty (30) days; and

                  (e)      A failure by Tenant in the performance of any other
                           term, covenant, agreement or condition of this Lease
                           on the part of Tenant to be performed after thirty
                           (30) days notice, or if such default cannot
                           reasonably be cured within said thirty (30) days
                           period and Tenant does not commence to diligently
                           pursue the same within said thirty (30) day period ad
                           to continue to diligently pursue the same until
                           remedied.

Landlord agrees that it shall not exercise any rights or remedies, which are
available to it pursuant to the terms of Section 17, as a result of an event of
default described in Section 16(b) or (d) above, unless and until Landlord has
provided Tenant with a period of thirty (30) days after receipt of written
notice thereof within which to cure such default.

         17.      LANDLORD'S RIGHTS UPON TENANT'S DEFAULT. Upon default by
Tenant of any of the terms or covenants of this Lease, Landlord shall be
entitled to remedy such default as follows:

                  (a) Landlord shall have the right, immediately or at any time
after said default, without further notice to Tenant (unless otherwise provided
herein), to enter the Leased Premises, without terminating this Lease or being
guilty of trespass, and do any and all acts as Landlord may deem necessary,
proper or

                                      -18-
<PAGE>

convenient to cure such default, for the account and at the expense of Tenant,
and Tenant agrees to pay to Landlord as Additional Rent all damage and/or
expense incurred by Landlord in so doing, including interest at the Penalty Rate
from the due date until the date payment is received by Landlord. The making of
such payment or the taking of such action by Landlord shall not be deemed to
cure the default or to stop Landlord from the pursuit of any remedy to which
Landlord would otherwise be entitled.

                  (b) Landlord shall, following said default, have the right to
terminate this Lease and/or Tenant's right to possession of the Leased Premises
and remove Tenant, any occupant and any property therefrom, without being guilty
of trespass and without relinquishing any rights of Landlord against Tenant.
Landlord shall be entitled to recover damages from Tenant in an amount equal to
the amount herein covenanted to be paid as Minimum Annual Rent during the
remainder of the Lease Term, said Minimum Annual Rent for the full term then
remaining having been fully accelerated at the option of Landlord, together with
(i) all reasonable expenses of any proceedings (including, but not limited to,
legal expenses and attorney's fees) which may be necessary in order for Landlord
to recover possession of the Leased Premises, (ii) the reasonable expenses of
the re-renting of the Leased Premises (including, but not limited to, any
commissions paid to any real estate agent, advertising expense and the costs of
such alterations, repairs, replacements and decoration or re-decoration as
Landlord, in its sole judgment reasonably exercised, considers advisable and
necessary for the purpose of re-renting the Leased Premises), and (iii) interest
computed at the Penalty Rate from the due date until paid; provided, however,
that said damages shall be discounted to present value using a discount factor
of 5%, and further that there shall be credited against the amount of such
damages all amounts received by Landlord from such re-renting of the Leased
Premises and such amounts shall be refunded to Tenant. No act or thing done by
Landlord shall be deemed to be an acceptance of a surrender of the Leased
Premises, unless Landlord shall execute a written agreement of surrender with
Tenant. Tenant's liability hereunder shall not be terminated by the execution of
a new lease of the Leased Premises by Landlord. In the event Landlord does not
exercise its option to accelerate the payment of Minimum Annual Rent as provided
hereinabove, then Tenant agrees to pay to Landlord, upon demand, the amount of
damages herein provided after the amount of such damages for any month shall
have been ascertained; provided, however, that any expenses incurred by Landlord
shall be deemed to be a part of the damages for the month in which they were
incurred. Separate actions may be maintained each month or at other times by
Landlord against Tenant to recover the damages then due, without waiting until
the end of the term of this Lease to determine the aggregate amount of such
damages.

                                      -19-
<PAGE>

                  (c) Upon any default by Tenant to pay Minimum Annual Rent or
Additional Rent, Landlord shall have a lien upon the property of Tenant in the
Leased Premises for the amount of any unpaid Minimum Annual Rent or Additional
Rent.

                  (d) All rights and remedies provided to either Landlord or
Tenant herein as a result of a default by the other party shall be cumulative,
and none shall exclude any other right or remedy allowed by law. For the
purposes of any suit brought or based hereon, this Lease shall be construed to
be a divisible contract, to the end that successive actions may be maintained on
this Lease as successive periodic sums mature hereunder.

         18.      LENDER REQUIREMENTS.

                  (a) SUBORDINATION. Tenant agrees that this Lease (including
without limitation the option to purchase contained herein) is subject and
subordinate to the lien of any existing mortgage or deed of trust which is a
lien upon the Property or any part thereof on the Rent Commencement Date, and to
all renewals, modifications, consolidations, replacements and extensions
thereof, and to all advances made or hereafter to be made upon the security
thereof. Landlord agrees that it shall acquire from any such existing mortgagee
or holder of an existing deed of trust a non-disturbance agreement in such
lender's usual form for the benefit of Tenant. Tenant agrees that this Lease
(including without limitation the option to purchase contained herein) is and
shall be subject and subordinate to the lien of any future mortgages or deeds of
trust which at any time during the Lease Term may be made a lien upon the
Property or any part thereof, and to all advances made or hereafter to be made
upon the security thereof; provided that such subordination shall be effective
only upon the delivery to Tenant of a non-disturbance agreement in such lender's
usual form and reasonably satisfactory to Tenant for the benefit of Tenant by
such future mortgagee or holder of a deed of trust. These subordination
provisions shall be self-operative and no further instrument of subordination
shall be required. Tenant agrees to execute and deliver, upon request, such
further instrument or nstruments confirming this subordination as shall be
reasonably desired by Landlord or by any mortgagee or proposed mortgagee. Tenant
further agrees that, at the option of the holder of any mortgage or of the
trustee under any deed of trust, this Lease may be made superior to said
mortgage or deed of trust by the insertion therein of a declaration that this
Lease is superior thereto, and to all renewals, modifications, consolidations,
replacements and extensions thereof.

                  (b) ATTORNMENT. In the event any proceedings are brought for
the foreclosure of, or in the event of exercise of the power of sale under, any
deed to secure a debt given by Landlord and covering the Leased Premises, Tenant
shall execute such attornment agreement as shall be reasonably required by said
purchaser, pursuant to the terms of which Tenant recognizes such

                                      -20-
<PAGE>

purchaser as the owner and landlord under this Lease, and the purchaser
recognizes Tenant as the tenant under this Lease.

                  (c) NOTICE TO MORTGAGEE UPON LANDLORD DEFAULT. Tenant agrees
to give any mortgagee by certified mail, return receipt requested, a copy of any
notice of default served upon Landlord, provided that before such notice Tenant
has been notified in writing of the address of such mortgagee. Tenant further
agrees that if Landlord shall have failed to cure such default within the time
provided for in this Lease, then mortgagee shall have an additional fifteen (15)
days within which to cure such default; provided, however, that if such default
cannot be reasonably cured within that time, then such mortgagee shall have such
additional time as may be necessary to cure such default so long as mortgagee
has commenced and is diligently pursuing the remedies necessary to cure such
default (including, without limitation, the commencement of foreclosure
proceedings, if necessary), in which event this Lease shall not be terminated
while such remedies are being so diligently pursued. In the event of the sale of
the Property or the Leased Premises, by foreclosure or deed in lieu thereof, the
mortgagee or purchaser at such sale shall be responsible for the return of any
security deposit only to the extent that such mortgagee or purchaser actually
received the security deposit. In addition, Tenant shall not pay any rental
hereunder for more than one (1) month in advance.

         19.      ESTOPPEL CERTIFICATES. Landlord and Tenant agree, at any time
and from time to time, upon not less than five (5) business days prior notice by
the other, to execute, acknowledge and deliver to the other a statement in
writing (i) certifying that this Lease is unmodified and in full force and
effect (or if there have been modifications the nature of same), (ii) stating
the dates to which the Minimum Annual Rent and Additional Rent have been paid by
Tenant, (iii) stating whether or not to the best knowledge of either Landlord or
Tenant, the other is in default in the performance of any covenant, agreement or
condition contained in this Lease, and, if so, specifying each such default of
which either Landlord or Tenant may have knowledge, (iv) stating he address to
which notices to either Landlord or Tenant should be sent, and (v) certifying
such other materials as may be requested by Tenant or Landlord. Any such
statement delivered pursuant hereto may be relied upon by an owner of the
Property, any prospective purchaser of the Property or the Leasehold Interest,
any mortgagee or prospective mortgagee of the Property or the Leasehold
Interest, or of Landlord's or Tenant's interest therein, or any prospective
assignee of any such mortgage or the Leasehold Interest.

         20.      DAMAGE BY FIRE OR OTHER CASUALTY.

                  (a) RESTORATION. If the Leased Premises shall be damaged by
fire or other casualty but such damage does not render the Leased Premises
wholly unfit for Tenant's business operations as shall be determined by Landlord
and Tenant in their reasonable

                                      -21-
<PAGE>

business judgment, Landlord, at Landlord's expense, shall promptly restore the
Leased Premises, and Tenant, at Tenant's sole expense, shall promptly restore
all leasehold improvements installed in the Leased Premises by Tenant or at
Tenant's request and its own furniture, furnishings, trade fixtures and
equipment. No penalty shall accrue for reasonable delay which may arise by
reason of adjustment of insurance on the part of Landlord, or on account of
labor problems, or any other cause beyond Landlord's reasonable control. Minimum
Annual Rent and Additional Rent shall abate proportionately (based on the
proportion of the number of square feet rendered untenantable to the total
number of square feet of the Leased Premises), from the date of the damage or
destruction until the date the Landlord has substantially completed such
restoration. Notwithstanding anything stated to the contrary herein, in the
event that such damage shall occur during the last year of the Lease term,
Landlord shall not be required to restore the Leased Premises nor shall Tenant
be required to restore the Leasehold Improvements, furnishings, furniture,
fixtures or equipment.

                  (b) TERMINATION. If the Leased Premises are substantially
damaged or are rendered substantially untenantable by fire or other casualty
during the Lease Term to such an extent that it is rendered substantially
unusable by Tenant for the purposes originally contemplated by this Lease or
access is denied, Landlord shall restore or repair the same unless expressly not
required to do so under Section 20(c). If such damage occurs, however, at any
time during the Lease Term, and (i) Landlord's architect certifies that the
Leased Premises cannot be repaired within one hundred twenty (120) working days
of normal working hours, said period commencing on the casualty date, or (ii)
Landlord shall decide to demolish the Leased Premises or not to rebuild it, then
Landlord or Tenant may, within ninety (90) days after such fire or other
casualty, terminate this Lease by giving Tenant notice of such decision, and
thereupon the Lease Term shall expire by lapse of time upon the third day after
such notice is given, and Tenant shall thereupon vacate the Leased Premises and
surrender the same to Landlord. In the event that damage to the Leased Premises
is not repaired sufficiently within one hundred eighty (180) days after such
fire or other casualty so that Tenant can commence to refixture the Leased
Premises for the use thereof as originally contemplated by this Lease, then
Tenant shall have the right to terminate this Lease by giving Landlord written
notice thereof within thirty days of the end of such period, and thereupon the
Lease Term shall expire by lapse of time upon the thirty days after such notice
is given, and Tenant shall thereupon vacate the Leased Premises and surrender
the same to Landlord. Upon the termination of this Lease under the conditions
hereinbefore provided, Tenant's liability for Minimum Annual Rent 3 - and
Additional Rent shall cease as of the day following the casualty.

                                      -22-
<PAGE>

                  (c) LENDER'S APPROVAL. Notwithstanding anything to the
contrary in this Section or in any other provision of this Lease, any obligation
(under this Lease or otherwise) of Landlord to restore all or any portion of the
Leased Premises shall be subject to Landlord's receipt of approval of the same
by the mortgagee(s) of Landlord (and any other approvals required by applicable
laws), as well as receipt from any such mortgagee(s) of such fire and other
hazard insurance policy proceeds as may have been assigned to any such
mortgagee; it being agreed that if Landlord has not received such approval(s)
and proceeds within one hundred and eighty (180) days after any such casualty,
then Landlord shall have the option to terminate this Lease, at any time
thereafter, by notice to Tenant. Landlord shall diligently pursue the receipt of
all approvals and insurance policy proceeds which are described in this Section
20(c).

         21.      CONDEMNATION. In the event the whole or a "substantial part"
(as hereinafter defined) of the Leased Premises shall be taken for any public or
quasi-public purpose by any lawful power or authority by exercise of the right
of appropriation, condemnation or eminent domain, or sold to said authority to
prevent such taking (collectively referred to herein as a "taking"), this Lease
shall terminate effective as of the date possession is required to be
surrendered to said authority, and the Minimum Annual Rent and Additional Rent
shall be apportioned as of the date. For purposes of this Section, a
"substantial part" of the Leased Premises shall be considered to have been taken
if access to or fifty percent (50%) or more of the Leased Premises or any
material part which is necessary to continue manufacturing in accordance with
F.D.A. licensing requirements is taken or condemned. Tenant shall not assert any
claim against Landlord or the taking authority for any compensation arising out
of or related to such taking and Landlord shall be entitled to receive the
entire amount of any award without deduction for any estate or interest of
Tenant; provided, however, that nothing contained in this section shall be
deemed to give Landlord any interest in any award made to Tenant for the taking
of personal property and fixtures belonging to Tenant or for Tenant's moving
expenses, as long as such award is made in addition to and separately stated
from any award made to Landlord for the Leased Premises and the Property. If
less than fifty percent (50%) of the Leased Premises is so taken, the Lease
shall continue to be in full force and effect, and the Minimum Annual Rent and
Additional Rent shall be adjusted (based on the ratio that the number of square
feet of rentable area taken from the Leased Premises bears to the number of
rentable square feet in the Leased Premises immediately prior to such taking) as
of the date possession is required to be surrendered to said authority;
provided, however, Landlord shall have the right to determine that the Leased
Premises should be demolished and not rebuilt, in which event Landlord may,
within ninety (90) days after such decision, and thereupon the Lease Term shall
expire by lapse of time upon the third day after such notice is given, and
Tenant shall thereupon vacate the Leased Premises and surrender the same to
Landlord. In

                                      -23-
<PAGE>

the event that the Lease remains in full force and effect in accordance with the
terms described above, Landlord shall be obligated to repair and restore the
Leased Premises to usable condition by Tenant, and such repair shall be a
condition precedent to the continued effectiveness of this Lease. Landlord shall
have no obligation to contest any taking.

         22.      LANDLORD'S LIABILITY. Landlord, or its agents, shall not be
liable for any injury or damage to persons or property resulting from fire,
explosion, falling plaster, steam, gas, electricity, water, rain, or leaks from
any part of the Leased Premises, or from the pipes, conduits, appliances or
plumbing works, or by dampness or by any other cause of whatsoever nature,
unless caused by or due to the gross negligence of Landlord, its agents,
servants, or employees. All personal property and equipment located in the
Leased Premises shall be at the risk of Tenant.

         23.      TENANT'S AND LANDLORD'S LIABILITY. Tenant shall reimburse
Landlord for all expense, damage or fines, incurred or suffered by Landlord by
reason of any breach, violation or nonperformance by Tenant, or its agents,
servants, or employees, of any covenant or provision of this Lease or the Rules
and Regulations promulgated by Landlord hereunder from time to time, or by
reason of damage to persons or property caused by moving property of or for
Tenant in or out of the Property, or by the installation or removal of furniture
or other property of or for Tenant, or by reason of or arising out of the
carelessness, negligence or improper conduct of Tenant, or its agents, servants,
employees, invitees or licensees in the use or occupancy of the Leased Premises
or the common areas of the Property. Landlord shall reimburse Tenant for all
expenses, damages or fines, incurred or suffered by Tenant by reason of any
breach, violation or nonperformance by Landlord, or its agents, servants, or
employees, of any covenant or provision of this Lease, or by reason of or
arising out of the carelessness, negligence or improper conduct of Landlord, or
its agents, servants, employees, invitees or licensees.

         24.      INDEMNITY.

                  (a) BY TENANT. Tenant shall indemnify and defend Landlord and
its agents and employees and save them harmless from and against any and all
claims, actions, damages, liabilities and expense in connection with loss of
life, personal injury and/or damage to property arising from or out of, the
occupancy or use by Tenant of the Leased Premises or any part thereof, or
occasioned wholly or in part by any act or omission of the Tenant, its agents,
contractors, employees, servants, invitees or licensees, whether inside the
Leased Premises or elsewhere in the Property.

                  (b) BY LANDLORD. Landlord shall indemnify and defend Tenant
and its agents and employees to save them harmless from and against any and all
claims, actions, damages, liabilities and expense in connection with loss of
life, personal injury and/or

                                      -24-
<PAGE>

damage to property occasioned wholly or in part by any act or omission of the
Landlord, its agents, contractors, employees, servants, invitees or licensees,
whether inside the Leased Premises or elsewhere in the Property.

         25.      TENANT'S INSURANCE.

                  (a) COVERAGES. Tenant shall have issued, pay the premiums
therefor, and maintain in full force and effect during the Lease Term and any
option period:

                           (i)   COMPREHENSIVE LIABILITY. A commercial general
                                 liability insurance policy or policies in which
                                 the Landlord and Landlord's Mortgagee(s) (and
                                 such additional persons and/or entities as
                                 Landlord may request) and Tenant shall be the
                                 insured, protecting the Landlord and Landlord's
                                 mortgagee(s) (and such additional persons
                                 and/or entities as Landlord may request) and
                                 Tenant in the amount of at least Three Million
                                 and No/100 Dollars ($3,000,000.00) combined,
                                 single limit coverage for bodily injury,
                                 including death, or property damage, which
                                 amount may be increased from time to time by
                                 Landlord in its reasonable determination;

                           (ii)  ALL-RISK CASUALTY.  All-risk casualty
                                 insurance, naming Landlord (and such additional
                                 persons and/or entities as Landlord may
                                 request) and Tenant as insureds (as their
                                 interests may appear); written at replacement
                                 cost value and with replacement cost
                                 endorsement, covering all leasehold
                                 improvements installed in the Leased Premises
                                 by Tenant or at Tenant's request and all of
                                 Tenant's personal property in the Leased
                                 Premises (including, without limitation,
                                 inventory, trade fixtures, floor coverings,
                                 furniture and other property removable by
                                 Tenant under the provisions of this Lease).

                          (iii)  WORKERS' COMPENSATION. If and to the extent
                                 required by law, workers' compensation and
                                 employer's liability or similar insurance in
                                 form and amounts required by law.

                  (b) POLICY REQUIREMENTS. Tenant's failure to provide such
insurance or failure to pay the premiums when due, shall be deemed a default
hereunder. Any monies expended by Landlord to cure said default shall be deemed
Additional Rent and shall be due and owing with Tenant's next payment of Basic
Monthly Rent. All such policies shall contain only such reasonable deductible
amounts as may be provided in advance by Landlord and shall

                                      -25-
<PAGE>

contain a provision that Landlord shall receive not less than thirty (30) days
advance notice in writing from the insurance company of any intention of the
insurance company to cancel such policy or policies. Tenant shall provide
written evidence to Landlord of its acquisition of such policies prior to the
commencement of this Lease and prior to any renewal date of such policies. All
policies shall be carried with a reputable insurance company qualified to do
business in the State of Maryland and rated not lower than A-XII in the A.M.
Best Rating Guide.

                  (c) NO LIMITATION OF LIABILITY. Neither the issuance of any
insurance policy required under this Lease nor the minimum limits specified
herein shall be deemed to limit or restrict in any way Tenant's liability
arising under or out of this Lease.

         26.      WAIVER OF SUBROGATION. Landlord and Tenant mutually covenant
and agree that each party, in connection with insurance policies required to be
furnished in accordance with the terms and conditions of this Lease, or in
connection with insurance policies which they obtain insuring such insurable
interest as Landlord or Tenant may have in its own properties, whether personal
or real, shall expressly waive any right of subrogation on the part of the
insurer against the Landlord (and any mortgagee requested by Landlord) or Tenant
as the same may be applicable, which right to the extent not prohibited or
violative of any policy is hereby expressly waived, and Landlord and Tenant each
mutually waive all right of recovery against each other, their agents, or
employees for any loss, damage or injury of any nature whatsoever to property or
person for which either party carries insurance or is required by this Lease to
carry insurance.

         27.      NO LIENS PERMITTED; DISCHARGED. Tenant will not permit to be
created or to remain undischarged any lien, encumbrance or charge (arising out
of any work done or materials or supplies furnished, or claimed to have been
done or furnished, by any contractor, mechanic, laborer or materialman or any
mortgage, conditional sale, security agreement or chattel mortgage, or otherwise
by or for Tenant) which might be or become a lien or encumbrance or charge upon
the Property or any part thereof or the income therefrom. If any lien, or notice
of Lien on account of an alleged debt of Tenant or any notice of contract by a
party engaged by Tenant or Tenant's contractor to work on the Leased Premises
shall be filed against the Property or any part thereof, Tenant, within thirty
(30) days after notice of the filing thereof, will cause the same to be
discharged of record by payment, deposit, bond, order of a court of competent
jurisdiction or otherwise. If Tenant shall fail to cause such lien or notice of
lien to be discharged within the period aforesaid, then, in addition to any
other right or remedy, Landlord may, but shall not be obligated to, discharge
the same either by paying the amounts claimed to be due or by procuring the
discharge of such lien by deposit or by bonding proceedings and in any such
event Landlord shall be entitled, if Landlord so elects, to compel the

                                      -26-
<PAGE>

prosecution of an action for the foreclosure of such lien by the lienor and to
pay the amount of the judgment in favor of the lienor with interest, costs and
allowances. Any amount so paid by Landlord and all reasonable costs and
expenses, including attorneys' fees, incurred by Landlord in connection
therewith, shall constitute Additional Rent payable by Tenant under this Lease
and shall be paid by Tenant to Landlord on demand. Nothing herein contained
shall obligate Tenant to pay or discharge any lien created by Landlord.

         28.      SIGNS, AWNINGS AND CANOPIES. Tenant may place or suffer to be
placed or maintained on the exterior of the Leased Premises any sign, awning or
canopy, or other written matter of any kind, provided that any such sign,
awning, canopy or written matter is in compliance with the applicable federal,
state and/or country regulations. Tenant further agrees to maintain in good
condition and repair at all times such sign, awning, canopy, decoration,
lettering, or written mater as may be approved.

         29.      ENVIRONMENTAL PROTECTION. Tenant and Tenant's employees and
agents shall not dispose of any oil, petroleum or chemical liquids or solids,
liquid or gaseous products or any hazardous waste or hazardous substance
including, without limitation, asbestos (hereinafter collectively referred to as
"hazardous waste"), as those terms are used in the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980, or in any other federal,
state or local law governing hazardous substances, as such laws may be amended
from time to time (hereinafter collectively referred to as the "Act"), at, upon,
under or within the Leased Premises or the Property, or into the plumbing or
sewer or water system servicing the Leased Premises and/or the Property, nor
shall Tenant, its agents or employees cause or permit the discharge, spillage,
uncontrolled loss, seepage or filtration of any hazardous waste at, upon, under
or within the Leased Premises of the Property or into the plumbing or sewer or
water system servicing the same. Notwithstanding the foregoing, Landlord
acknowledges that the use which Tenant contemplates for the Leased Premises
involves the use, storage, and disposal of materials which are defined herein as
hazardous waste, and Tenant shall have the right to maintain such materials on
the Leased Premises so long as they are used, stored and disposed of in
accordance with the Act. Tenant shall comply in all respects with the
requirements of the Act and related regulations, and shall notify Landlord
immediately in the event of its discovery of any hazardous waste at, upon, under
or within the Leased Premises or the Property which has not been used, stored or
disposed of in accordance with the Act. Tenant shall advise Landlord, in
writing, of the identities of hazardous wastes being used and stored in the
Leased Premises promptly upon written request from Landlord, but in no event
less frequently than once every twelve (12) months. Tenant shall indemnify
Landlord against all costs, expenses, liabilities, losses, damages, injunctions,
suits, fines, penalties, claims, and demands, including reasonable attorneys'
fees, arising out of any violation of or default by

                                      -27-
<PAGE>

Tenant, and its employees and agents, in the covenants of this Section. The
provisions of this Section shall survive the expiration of the Lease Term.

         30.      NOTICES. All notices to be given under this Lease shall be in
writing and either (i) hand-delivered, (ii) sent by Federal Express (or other
nationally recognized, overnight mail courier service), (iii) or mailed by
United States Certified or Registered Mail, return receipt requested, postage
prepaid. Notices should be delivered as follows:

                  (a)      To Landlord to the attention of President at the
                           business and mailing address stated on page 1 of this
                           Lease.

                  (b)      To Tenant to the attention of President, at the
                           business and mailing address stated on page 1 of this
                           Lease.

                           With a copy to:  Donovan, Leisure, Newton & Irvine
                                            30 Rockefeller Plaza
                                            New York, NY 10112

                                            Attn: William J.T. Brown, Esq.

Any such notice shall be deemed to be received on the date it is hand-delivered
or delivered by Federal Express (or other nationally recognized, overnight mail
courier service), or on the third day after the date on which it is deposited in
the U.S. mails. Landlord and Tenant shall each have the right to change the
person and/or address to which notices shall be delivered upon notice thereof to
the other parties sent pursuant to the provisions of this paragraph.

         31.      TIME. Except as expressly set forth herein to the contrary,
Landlord and Tenant acknowledge that time is of the essence in the performance
of any and all obligations, terms, and provisions of this Lease.

         32.      POSTPONEMENT OF PERFORMANCE. In the event that either party
hereto shall be delayed or hindered in or prevented from the performance of any
act required hereunder by reason of strikes, labor troubles, inability to
procure labor or materials, failure of power, restrictive governmental laws or
regulations, riots, insurrection, war, acts of God, fire or other casualty or
other reason of a similar or dissimilar nature beyond the reasonable control of
the party delayed in performing work or doing acts required under the terms of
this Lease, then performance of such act shall be excused for the period of the
delay and the period for the performance of any such act shall be extended for a
period equivalent to the period of such delay; provided, however that nothing in
this section shall excuse any delay in the payment of Minimum Annual Rent or
Additional Rent; and provided, further, that delays or failures to perform
resulting from lack of funds

                                      -28-
<PAGE>

shall not be deemed delays beyond the reasonable control of a party. Nothing
contained herein shall be construed to limit the provisions concerning the
abatement of Minimum Annual Rent and Additional Rent resulting from fire and
casualty damage or from condemnation damage to the Leased Premises as more fully
described in Sections 20 and 21 hereof.

         33.      BROKERS. Landlord and Tenant represent and warrant each to the
other that neither has authorized any broker, agent or finder purporting to act
on either's behalf in respect to this Lease transaction, and each hereby agree
to indemnify and hold harmless one from the other from and against any cost,
expense, claims, liability or damage resulting from a breach of the
representation and warranty herein contained.

         34.      NO WAIVER. No waiver by Landlord or Tenant of any breach of
any of the terms, convenants, agreements, or conditions of this Lease shall be
deemed to constitute a waiver of any succeeding breach thereof, or a waiver of
any breach of any of the other terms, convenants, agreements, and conditions
herein contained. No provision of this Lease shall be deemed to have been waived
by Landlord or Tenant, unless such waiver be in writing signed by such party. No
employee of Landlord or of Landlord's agents shall have any authority to accept
the keys of the Leased Premises prior to termination of the Lease, and the
delivery of keys to any employee of Landlord or Landlord's agents shall not
operate as a termination of the Lease or a surrender of the Leased Premises. The
receipt by Landlord of any payment of the Minimum Annual Rent or Additional Rent
with knowledge of the breach of any covenant of the Lease shall not be deemed a
waiver of such breach. The failure of Landlord to enforce any of the Rules and
Regulations, hereafter adopted, against Tenant or any other tenant in the
Property shall not be deemed a waiver of any such Rules and Regulations.

         35.      AMENDMENTS. This Lease and the Exhibits attached hereto,
together with the terms and conditions of that certain Stock Purchase Agreement
between Landlord, Tenant and Cambridge Biotech Corporation, debtor, contain the
entire agreement between the parties pertaining to the subject matter hereof,
and any agreement hereafter made shall be ineffective to change, modify,
discharge or effect an abandonment in whole or in part unless such agreement is
in writing and signed by the party against whom enforcement of the change,
modification, discharge or abandonment is sought.

         36.      APPLICABLE LAW. The laws of the State of Maryland shall govern
the validity, performance and enforcement of this Lease.

         37.      TRANSFER OF THE PROPERTY. In the event of the sale or other
transfer of landlord's right, title and interest in the Leased Premises or the
Property, Landlord shall transfer and assign to such purchaser or transferee all
amounts of pre-paid Minimum Annual Rent and Additional Rent, and provided that
the

                                      -29-
<PAGE>

purchaser or transferee shall assume all of the surviving liabilities and
obligations of Landlord hereunder accruing after the consummation of such sale
or transfer, Landlord thereupon shall be released from all liability and
obligations hereunder derived from this Lease arising out of any act, occurrence
or omission relating to the Leased Premises or this Lease occurring after the
consummation of such sale or transfer. Tenant shall have no right to terminate
this Lease, to abate Minimum Annual Rent or Additional Rent, nor to deduct from,
nor set-off, nor counterclaim against Minimum Annual Rent or Additional Rent
because of any sale or transfer (including, without limitation, any
sale-leaseback) by Landlord or its successors or assigns.

         38.      OPTION TO PURCHASE. At any time during the term hereof,
provided that Tenant is not then in default hereof and provided further that
Tenant, or a permitted assignee (which is a related party to Tenant pursuant to
the provisions of Section 14 hereof) shall then occupy the Leased Premises,
Tenant shall have the option to purchase the Property (subject only to the
rights of the tenant under the BTRL Lease as to Parcel 1) at the then Fair
Market Value (the "FMV") as of the date of the exercise of the option (subject
to the provisions of the next succeeding paragraph). Tenant shall exercise this
option by giving written notice to Landlord, setting forth its determination of
the FMV. In the event Landlord does not agree with this determination, then the
FMV shall be determined by independent appraisal in the same manner as is set
forth in Section 3(b) hereof for determining Fair Rental Value, provided that
such appraisal shall take into account the remaining terms of any leases then
encumbering the Property, including this Lease, without regard to the effect, if
any, of any merger or termination thereof which may result from the exercise of
this Option.

         Landlord shall satisfy and discharge of record any mortgage on the
Property and deliver a warranty deed in the customary form, subject only to such
encumbrances as the Property is subject to on the date hereof as set forth on
Exhibit A, liens for taxes not yet due and payable and such additional
encumbrances (not including mortgage or liens) as do not materially interfere
with the use of the Property as contemplated by this Lease, and Tenant shall pay
the consideration no later than sixty (60) days from the receipt of the notice
of option, or, in the event the appraisal process is required, and within ten
(10) days of such determination Tenant confirms its intention to buy at the FMV
as so determined, within thirty (30) days from the date of determination of the
FMV. In the event the Property shall be encumbered by a mortgage(s) (the
"Mortgage") held by an institutional lender(s) which shall have a balance in
excess of the FMV (the "Excess Balance"), in order to exercise the option Tenant
shall pay in addition to the FMV an amount equal to the lesser of (i) Excess
Balance or (ii) the amount by which 80% of FMV determined as of the date the
Mortgage was granted exceeds FMV at the time the option is exercised; provided,
however, that if any mortgage encumbering the Property at the date hereof
continues to encumber the Property at the date

                                      -30-
<PAGE>

of exercise of this option the sum of FMV and any amount paid pursuant to
subsection (i) or (ii) above shall in no event be less then the amount necessary
to discharge such mortgage (without regard to any mortgage subsequently
attaching). There shall not be taken into account for the purposes of this
calculation a Mortgage which encumbers property in addition to the Property
unless Tenant shall have consented in writing to an allocation to the Property
of a portion of the Mortgage encumbering such additional property.

         39.      OPTION ON ADDITIONAL SPACE. Tenant shall have the option to
lease the additional space currently leased to BTRL contracts and Services, Inc.
pursuant to a lease dated June 30, 1992 (the "BTRL Lease") upon the expiration
or sooner termination of the BTRL Lease, provided that Tenant shall give written
notice to Landlord of its election to exercise such option no later than 180
days prior to the expiration date of the BTRL Lease or within sixty (60) days
after written notice of the sooner termination of the BTRL Lease, at a rental
rate equal to the then-prevailing square-foot rental rate under this Lease and
otherwise on the terms and conditions set forth herein. This Lease shall be
amended to add the space demised under the BTRL Lease upon the exercise of the
option.

         40.      PROCEDURE TO REQUIRE PURCHASE OR TERMINATION OF OPTION. If at
any time during the term of this Lease, Landlord shall receive a bona fide offer
to purchase the Property from a third party, which offer Landlord desires to
accept, Landlord shall promptly deliver to Tenant a copy of such offer. Tenant
may, within thirty (30) days after receipt of such offer, elect to purchase the
Property on the same terms and conditions as set forth in such offer by delivery
to Landlord of written notice of said exercise. In the event Tenant does not so
elect to purchase, Landlord shall be free to sell the Property to the third
party offeror on terms and conditions which are substantially the same as set
forth in the offer, in no material respect less favorable to the Landlord, and
subject to the terms of this Lease except that Tenant's Option to Purchase shall
be extinguished. In the event the third party sale is not consummated, the
Option to Purchase shall remain in effect.

         41.      WAIVER OF COUNTERCLAIM AND TRIAL BY JURY/ATTORNEYS FEES.
Landlord and Tenant waive their right to trial by jury in any action, proceeding
or counterclaim brought by either of the parties hereto against the other
(except for personal injury or property damage) on any matters whatsoever
arising out of or in any way connected with this Lease, the relationship of
Landlord and Tenant, Tenant's use of or occupancy of the Lease Premises, and any
emergency statutory or any other statutory remedy. Tenant shall not interpose
any counterclaim(s) or claim(s) for set-off, recoupment or deduction of Minimum
Annual Rent or Additional Rent in a summary proceeding for nonpayment of
Minimum Annual Rent or Additional Rent, unless such counterclaim is mandatory in
nature and must be interposed in such summary proceeding against the

                                      -31-
<PAGE>

other to enforce the terms and conditions of this Lease, the prevailing party
shall be entitled to recover all reasonable attorneys fees and costs incurred as
a result thereof.

         42.      SEPARABILITY. If any term or provision of this Lease or the
application thereof to any person or circumstances shall, to any extent, be
invalid or unenforceable, the remainder of this Lease or the application of such
term or provision to persons or circumstances other than those as to which it is
held invalid or unenforceable, shall not be affected thereby and each other term
and provision of this Lease shall be valid and enforceable to the fullest extent
permitted by law.

         43.      CORPORATE AUTHORITY. Concurrently with the execution of this
Lease, Tenant has delivered to Landlord a certified copy of a resolution of
Tenant's Board of Directors (or other evidence reasonably satisfactory to
Landlord) approving the leasing of the Leased Premises by Tenant pursuant to the
terms and conditions contained herein, stating that this Lease if fully binding
upon Tenant, and authorizing the execution of this Lease by each person signing
this Lease on behalf of Tenant.

         44.      INTERPRETATION.

                  (a) CAPTIONS. The captions; marginal references, General
Information sheet, and table of contents appearing in this Lease are inserted
only as a matter of convenience and in no way amplify, define, limit, construe,
or describe the scope or intent of this Lease nor in any way affect this Lease.

                  (b) GENDER. The Neuter, feminine or masculine pronoun when
used herein shall each include each of the other genders and the use of the
singular shall include the plural.

                  (c) COVENANTS. The parties hereto agree that all the
provisions of this Lease are to be construed as covenants and agreements as
though the words importing such covenants and agreements were used in each
separate provision hereof.

                  (d) INTERPRETATION. The provisions of this Lease although
initially drawn by Landlord were negotiated between the parties, and this Lease
shall not be construed for or against Landlord or Tenant, but this Lease shall
be interpreted in accordance with the general tenor of the language in an effort
to reach the intended result.

         45.      LANDLORD'S AGREEMENT RE: CONTRACT OF SALE OF THE PROPERTY.
Landlord agrees that, during the Lease Term and prior to its execution of any
contract for the sale of the Property to a prospective purchaser, it shall give
written notice of the existence of this Lease and Tenant's occupancy rights in
and to the Lease Premises (together with a copy of this Lease), to any such
prospective purchaser of the Property.

                                      -32-
<PAGE>

         46.      REASONABLENESS OF EXPENSES. Wherever it is required by the
terms of this Lease that one party reimburse the other party for costs and
expenses incurred in connection with the performance of an obligation or the
exercise of a right described herein, unless expressly stated otherwise, all
costs and expenses for which such reimbursement is sought shall be reasonable in
amount and nature, as determined in accordance with local standards of
commercial reasonableness in the District of Columbia metropolitan area.

         47.      LIMITS OF LANDLORD'S LIABILITY. In the event that any
mortgagee or holder of a deed of trust or other security interest in the
Property shall foreclose on the Property or accept a deed in lieu of foreclosure
as a result of the failure of Landlord to pay any debt secured by the Property,
then, thereafter, neither the owner of the Property, as Landlord, nor its
agents, employees or officers, whether disclosed or undisclosed, shall have any
personal liability under any provision of this Lease, and if such a subsequent
owner of the Property, as Landlord, defaults in the performance of any of its
obligations hereunder or otherwise, Tenant shall look solely to Landlord's
equity, interest and rights in the Property for satisfaction of Tenant's
remedies on account thereof.

         48.      BINDING EFFECT. This Agreement shall be binding upon and shall
inure to the benefit of the parties hereto, and the heirs, personal
representatives, successors and assigns of said parties.

         49.      RECORDING. Landlord and Tenant agree that, at the request of
either, each will execute a short form of this Lease in form satisfactory for
recording in the office of the Montgomery County Clerk.

                                      -33-
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have duly executed, sealed, and
delivered this lease, or have caused same to be executed, sealed and delivered
by their duly authorized attorney-in-fact, as of the day and year above written.

WITNESS/ATTEST:                        AQUILA BIOPHARMACEUTICALS, INC.

    /s/ WITNESS                        By:   /s/ AQUILA BIOPHARMACUETICALS, INC.
--------------------------------           -------------------------------------
                                            President

                                       Date of Execution: October 22, 1996
                                                          ----------------------

                                       BIOMERIEUX VITEK, INC.

                                       By:   /s/ BIOMERIEUX VITEK, INC.
                                           -------------------------------------
WITNESS/ATTEST:                             President

    /s/ WITNESS                        Date of Execution: October 22, 1996
--------------------------------                          ----------------------

                                      -34-
<PAGE>

                                    EXHIBIT A

                             DESCRIPTION OF PREMISES

1.     Property as described in a Confirmatory Deed from Biotech Research
Laboratories, Inc. to CBC recorded September 7, 1990 in Liber 9470 at folio 762
among the Land Records of Montgomery County, Maryland commonly known as 3 and 3
1/2 Taft Court.

       Subject to:

       a.     Ten (10) foot wide utility easement across the front of the lot as
shown on Plat recorded in Plat Book 102 at Plat 11503 among the Land Records of
Montgomery County, Maryland.

       b.     Portion of a Twenty (20) foot utility easement along the southwest
line of the property as shown on Plat recorded in Plat Book 102 at Plat 11503
among the Land Records of Montgomery County, Maryland.

       c.     Portion of a Ten (10) foot utility easement on the southeast line
of the property as shown on Plat recorded in Plat Book 102 at Plat 11503 among
the Land Records of Montgomery County, Maryland.

       d.     Portion of the "Fairway Easement", as shown along the
southeasterly line of the property as shown on Plat recorded in Plat Book 102 at
Plat 11503 among the Land Records of Montgomery County, Maryland.

       e.     Twenty (20) foot slope grading easement along the front of the
property to terminate on completion and acceptance of all public improvements by
the proper Governmental Authority, as dedicated by owner on Plat recorded in
Plat Book 102 at Plat 11503 among the Land Records of Montgomery County,
Maryland.

       f.     Right of Way to the Mayor and Council of Rockville, recorded in
Liber 6137 at Folio 845 among the Land Records of Montgomery County, Maryland.

       g.     Lease Agreement between Cambridge Biotech Corporation, a Delaware
corporation, Landlord, and BTRL Contracts and Services, Inc., a Massachusetts
corporation, Tenant, dated June 30, 1992, relating to building commonly known as
3 Taft Court.

2.     Property as described in a Confirmatory Deed from Biotech Research
Laboratories, Inc. to CBC recorded September 7, 1990 in Liber 9740 at Folio 758
among the Land Records of Montgomery County, Maryland commonly known as 1500
East Gude Drive.

                                    - A-1 -
<PAGE>

       Subject to:

       a.     Twenty-Five (25) foot access easement across Lot (9) to benefit
Lot (4) as shown on Plat recorded at Plat Book 114 at Plat No. 13548 among the
Land Records of Montgomery County, Maryland.

       b.     Thirty (30) foot Utility Easement as shown on Plat recorded at
Plat Book 114 at Plat No. 13548 among the Land Records of Montgomery County,
Maryland.

       c.     Right of Way to Chesapeake and Potomac Telephone Company recorded
in Liber 192 Folio 032.

       d.     Minimum Building Restriction Line per owner's dedication on
recorded plat.

       e.     Note on Plat, "The Access Easement for Lot 4 as recorded in Liber
5489 at folio 570 and the Public Service Drive and Utility Easement as recorded
in Plat Book 100 at Plat 11185 are abandoned by this plat, and the Easements
shown hereon are created by this Plat."

       f.     Effect of Note on Plat: "Upon dualization of Gude Drive, left
turns into this entrance will not be permitted."

       g.     Right of Way to Chesapeake and Potomac Telephone Company recorded
in Liber 248 Folio 054.

                                     - A-2 -
<PAGE>

                                   EXHIBIT A-1

                              Under Separate Cover

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