Document:

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                                                                     Exhibit 4.2

            THIS SECURITY (OR ITS PREDECESSOR) WAS ORIGINALLY ISSUED IN A
TRANSACTION EXEMPT FROM REGISTRATION UNDER THE UNITED STATES SECURITIES ACT OF
1933 (THE "SECURITIES ACT"), AND THIS SECURITY AND THE SHARES OF COMMON STOCK
ISSUABLE UPON CONVERSION HEREOF MAY NOT BE OFFERED, SOLD OR OTHERWISE
TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION
THEREFROM. EACH PURCHASER OF THIS SECURITY IS HEREBY NOTIFIED THAT THE SELLER OF
THIS SECURITY MAY BE RELYING ON THE EXEMPTION FROM THE PROVISIONS OF SECTION 5
OF THE SECURITIES ACT PROVIDED BY RULE 144A THEREUNDER.

            THE HOLDER OF THIS SECURITY AGREES FOR THE BENEFIT OF THE ISSUER
HEREOF THAT (A) THIS SECURITY AND THE SHARES OF COMMON STOCK ISSUABLE UPON
CONVERSION HEREOF MAY BE OFFERED, RESOLD, PLEDGED OR OTHERWISE TRANSFERRED, ONLY
(I) IN THE UNITED STATES TO A PERSON WHOM THE SELLER REASONABLY BELIEVES IS A
QUALIFIED INSTITUTIONAL BUYER (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT)
IN A TRANSACTION MEETING THE REQUIREMENTS OF RULE 144A, (II) PURSUANT TO AN
EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT PROVIDED BY RULE 144
THEREUNDER (IF AVAILABLE) OR (III) PURSUANT TO AN EFFECTIVE REGISTRATION
STATEMENT UNDER THE SECURITIES ACT, IN EACH OF CASES (I) THROUGH (III) IN
ACCORDANCE WITH ANY APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED
STATES, AND (B) THE HOLDER WILL, AND EACH SUBSEQUENT HOLDER IS REQUIRED TO,
NOTIFY ANY PURCHASER OF THIS SECURITY FROM IT OF THE RESALE RESTRICTIONS
REFERRED TO IN (A) ABOVE.

            THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE
INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITORY
OR A NOMINEE OF A DEPOSITORY OR A SUCCESSOR DEPOSITORY. THIS SECURITY IS NOT
EXCHANGEABLE FOR SECURITIES REGISTERED IN THE NAME OF A PERSON OTHER THAN THE
DEPOSITORY OR ITS NOMINEE EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE
INDENTURE, AND NO TRANSFER OF THIS SECURITY (OTHER THAN A TRANSFER OF THIS
SECURITY AS A WHOLE BY THE DEPOSITORY TO A NOMINEE OF THE DEPOSITORY OR BY A
NOMINEE OF THE DEPOSITORY TO THE DEPOSITORY OR ANOTHER NOMINEE OF THE
DEPOSITORY) MAY BE REGISTERED EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN
THE INDENTURE.

            UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE
OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE COMPANY
OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY
CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME
AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY

<PAGE>

PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN
AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR
VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED
OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS IN WHOLE, BUT
NOT IN PART, TO NOMINEES OF CEDE & CO. OR TO A SUCCESSOR THEREOF OR SUCH
SUCCESSORS NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL SECURITY SHALL BE
LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN
SECTION 2.16 OF THE INDENTURE.

<PAGE>

                                                           CUSIP No. 015351 AA 7
No. 001                                                             $110,550,000

                         ALEXION PHARMACEUTICALS, INC.

                 5 3/4% CONVERTIBLE SUBORDINATED NOTE DUE 2007

            ALEXION PHARMACEUTICALS, INC., a Delaware corporation (herein called
the "Company"), for value received, hereby promises to pay to Cede & Co. or
registered assigns, the principal sum of ONE HUNDRED AND TEN MILLION FIVE
HUNDRED AND FIFTY THOUSAND Dollars on March 15, 2007, and to pay interest
thereon as provided on the reverse hereof on the principal sum, until the
principal hereof and any unpaid and accrued interest is paid or duly provided
for. The right to payment of principal, premium, if any, and interest is
subordinated to the rights of Senior Indebtedness as set forth in the Indenture
referred to on the reverse side hereof.

            Interest Payment Dates: March 15 and September 15, with the first
payment to be made on September 15, 2000.

            Record Dates: March 1 and September 1.

<PAGE>

            IN WITNESS WHEREOF, ALEXION PHARMACEUTICALS, INC. has caused this
instrument to be duly signed.

                                        ALEXION PHARMACEUTICALS, INC.

                                        By: /s/ [ILLEGIBLE]
                                            ------------------------------------
                                            Name:
                                            Title:

                                        By: /s/ B.P. Luke
                                            ------------------------------------
                                            Name:
                                            Title

Dated: March 8, 2000

TRUSTEE'S CERTIFICATE OF
   AUTHENTICATION

This is one of the Securities referred
to in the within-mentioned Indenture.

THE CHASE MANHATTAN BANK, as Trustee

By: /s/ Kathleen Perry
    ----------------------------------
            Authorized Officer

<PAGE>

                         ALEXION PHARMACEUTICALS, INC.

                  5 3/4% CONVERTIBLE SUBORDINATED NOTE DUE 2007

            1. Interest. Alexion Pharmaceuticals, Inc., a Delaware corporation
(the "Company"), promises to pay interest on the principal amount of this
Security at the rate per annum shown above. The Company will pay interest
semi-annually in arrears on March 15 and September 15 of each year, with the
first payment to be made on September 15, 2000. Interest on the Securities will
accrue on the principal amount from the most recent date to which interest has
been paid or duly provided for or, if no interest has been paid, from March 8,
2000. Interest will be computed on the basis of a 360-day year of twelve 30-day
months.

            2. Maturity. The Securities will mature on March 15, 2007 unless
earlier convened, redeemed or repurchased pursuant to the terms hereof and the
Indenture.

            3. Method of Payment. The Company will pay interest on the
Securities (except defaulted interest) to the Persons who are registered Holders
of Securities at the close of business on the record date set forth on the face
of this Security next preceding the applicable interest payment date except that
(i) interest payable upon redemption or repurchase, unless the date of
redemption or repurchase is an interest payment date, will be payable to the
Person to whom the principal is payable and (ii) in the case of any Security or
portion of any Security that is converted into Common Stock during the period
from, but excluding, a record date for any interest payment date to, but
excluding, that interest payment date either (A) if the Security, or portion of
the Security, has been called for redemption on a redemption date that occurs
during that period, or is to be repurchased on a Repurchase Date that occurs
during that period, the Company will not be required to pay interest on that
interest payment date in respect of any Security, or portion of any Security,
that is so redeemed or repurchased; or (B) if otherwise, any Security or portion
of any Security that is not called for redemption but is submitted for
conversion during that period must be accompanied by funds equal to the interest
payable on that interest payment date on the principal amount so converted.
Holders must surrender Securities to a Paying Agent to collect the principal
payments. The Company will pay the principal, premium, if any, and interest in
money of the United States that at the time of payment is legal tender.
Principal and interest may, at the Company's option, be paid either (i) by check
mailed to the address of the Person entitled to the interest as it appears in
the register kept by the Registrar (provided (a) payments to the Depository will
be made by wire transfer of immediately available funds to the account of the
Depository or its nominee and (b) a Holder with an aggregate principal amount of
Securities in excess of $10 million will, at the written election of the Holder,
filed on or before the relevant record date with the Trustee, be paid by wire
transfer in immediately available funds); or (ii) by transfer to an account
maintained by that Person located in the U.S.

<PAGE>

            4. Paying Agent, Registrar, Conversion Agent. Initially, The Chase
Manhattan Bank (the "Trustee") will act as Paying Agent, Registrar and
Conversion Agent. The Company may change any Paying Agent, Registrar or
Conversion Agent without notice. The Company may act in any such capacity.

            5. Indenture. The Company issued the Securities under an Indenture
dated as of March 8, 2000 (the "Indenture") between the Company and the Trustee.
The terms of the Securities include those stated in the Indenture and those made
part of the Indenture by reference to the Trust Indenture Act of 1939 (15 U.S.
Code ss.ss. 77aaa-77bbbb) (the "Act") as in effect on the date of the Indenture.
The Securities are subject to all such terms, and Holders are referred to the
Indenture and the Act for a statement of such terms. The Securities are general
unsecured subordinated obligations of the Company limited to a maximum of
$120,000,000 aggregate principal amount (plus such additional amount (up to an
aggregate of $30,000,000) purchased by the Initial Purchasers pursuant to the
option described in Section 2.02), except as otherwise provided in the Indenture
(except for Securities issued in substitution for destroyed, mutilated, lost or
stolen Securities). Tens used herein which are defined in the Indenture have the
meanings assigned to them in the Indenture.

            6. Optional Redemption by the Company. At any time on or after March
20, 2003, the Company may redeem the Securities on at least 30 days' notice as a
whole or, from time to time, in part at the following prices, expressed as a
percentage of the principal amount, together with accrued interest to, but
excluding, the date fixed for redemption:

                                                                      Redemption
Period                                                                   Price
------                                                                ----------
Beginning March 20, 2003 and ending on March 14, 2004                  103.286%
Beginning March 15, 2004 and ending on March 14, 2005                  102.464%
Beginning March 15, 2005 and ending on March 14, 2006                  101.643%
Beginning March 15, 2006 and ending on March 14, 2007                  100.822%

and 100% on March 15, 2007. Any accrued interest becoming due on the date fixed
for redemption will be payable to the holders of record on the relevant record
date of the Securities being redeemed.

            7. Notice of Redemption. Notice of redemption pursuant to paragraph
6 will be mailed at least 30 days before the redemption date to each Holder of
Securities to be redeemed at its registered address. Securities in denominations
larger than $1,000 principal amount may be redeemed in part but only in whole
multiples of $1,000 principal amount. On and after the redemption date interest
ceases to accrue on Securities or portions of them called for redemption.

            8. Repurchase at Option of Holder. Pursuant to Section 3.07 of the
Indenture within 15 days after a Repurchase Event occurs, the Company is
required to give

<PAGE>

notice of the Repurchase Event to the Holders. Each Holder has he right, at its
option, to require the Company to repurchase all or any portion of the
Securities 40 days after the notice of repurchase event is mailed. The
Repurchase Price will be 105% of the principal amount of the Securities
submitted for repurchase, plus accrued and unpaid interest to, but excluding,
the Repurchase Date. If a Repurchase Date is an interest payment date, then the
interest payable on that date will be paid to the holder of record on the
relevant record date. Subject to the conditions of Section 3.07 of the
Indenture, the Company, at its option, instead of paying the Repurchase Price in
cash, may pay the Repurchase Price in Common Stock, valued at 95% of the average
of the Closing Prices for the five Trading Days immediately before and including
the third Trading Day preceding the Repurchase Date.

            9. Conversion. A Holder of a Security may convert the principal of
such Security into Common Stock at any time after the date of original issuance
of the Security to the close of business on the business day prior to March 15,
2007, or (x) if the Security is called for redemption by the Company, the Holder
may convert it at any time before the close of business on the date that is one
business day before the date fixed for such redemption, or (y) if the Security
is to be repurchased by the Company pursuant to paragraph 8 hereof, the Holder
may convert it at any time before the close of business on the date that is one
business day before the date fixed for such repurchase. The initial Conversion
Price is $106.425 per share of Common Stock, subject to adjustment in certain
circumstances as set forth in Section 10.06 of the Indenture. To determine the
number of shares issuable upon conversion of a Security, divide the principal
amount to be converted by the Conversion Price in effect on the conversion date
and round the result to the nearest 1/100th share. The Company is not required
to issue fractional shares of Common Stock upon conversion and, instead, will
pay a cash amount as provided in Section 10.03 of the Indenture. Except as
provided in Article Ten of the Indenture, no payment or adjustment for the
principal of, premium, if any, interest on or liquidated damages with respect
to, the Securities or for dividends on any Common Stock will be made. If a
Holder surrenders a Security for conversion between the record date for the
payment of interest and the next interest payment date, such Security, when
surrendered for conversion, must be accompanied by payment of an amount equal to
the interest thereon which the registered Holder on such record date is to
receive. A Security which the Holder has elected to be repurchased may be
converted only if the Holder withdraws its election to have such Security
repurchased in accordance with the terms of the Indenture before the close of
business on the business day prior to the Repurchase Date.

            To convert a Security a Holder must (1) complete and sign the
Conversion Notice, with appropriate signature guarantee, on the back of the
Security, (2) surrender the Security to a Conversion Agent, (3) furnish
appropriate endorsements and transfer documents if required by the Registrar or
Conversion Agent, (4) pay the amount of interest, if any, the Holder may be paid
as provided in the last sentence of the above paragraph and (5) pay any transfer
or similar tax if required. A Holder may convert a portion of a Security if the
portion is $1,000 principal amount or a whole multiple of $1,000 principal
amount.

<PAGE>

            Any shares issued upon conversion of a Security shall bear the
Private Placement Legend until after the second anniversary of the later of the
issue date for the Securities and the last date on which the Company or any
Affiliate of the Company was the owner of such shares or the Security (or any
predecessor security) from which such shares were converted (or such shorter
period of time as permitted by Rule 144(k) under the Securities Act or any
successor provision thereunder) (or such longer period of time as may be
required under the Securities Act or applicable state securities laws as set
forth in the Opinion of Counsel delivered to the Conversion Agent, unless
otherwise agreed by the Company and the Holder thereof).

            10. Subordination. The Securities are subordinated in right of
payment, in the manner and to the extent set forth in the Indenture, to the
prior payment in full of all Senior Indebtedness. Each Holder by accepting a
Security agrees to such subordination and authorizes the Trustee to give it
effect.

            11. Denominations, Transfer, Exchange. The Securities are in
registered form without coupons in denominations of $1,000 principal amount and
whole multiples of $1,000 principal amount. The transfer of Securities may be
registered and Securities may be exchanged as provided in the Indenture. The
Registrar may require a Holder, among other things, to furnish appropriate
endorsements and transfer documents. No service charge shall be made for any
such registration of transfer or exchange, but the Company may require payment
of a sum sufficient to cover any tax or other governmental charge payable in
connection therewith. The Registrar need not exchange or register the transfer
of any Security selected for redemption in whole or in part. Also, it need not
exchange or register the transfer of any Securities for a period of 15 days
before the mailing of a notice of redemption of the Securities selected to be
redeemed.

            12. Persons Deemed Owners. The registered Holder of a Security may
be treated as the owner of such Security for all purposes.

            13. Merger or Consolidation. The Company shall not consolidate with,
or merge into, or transfer or lease all or substantially all of its assets to,
any Person unless, among other things, the Person is organized under the laws of
the United States, any State thereof or the District of Columbia and such Person
assumes by supplemental indenture all the obligations of the Company under the
Securities, the Indenture and the Registration Rights Agreement and after giving
effect to the transaction no Default or Event of Default exists.

            Notwithstanding the foregoing, any subsidiary of the Company may
consolidate with, merge into or transfer all or part of its properties and
assets to the Company or any other subsidiary or subsidiaries of the Company.

            14. Amendments, Supplements and Waivers. Subject to certain
exceptions, the Indenture or the Securities may be amended or supplemented with
the consent of the Holders of at least a majority in aggregate principal amount
of the Securities then outstanding,

<PAGE>

and any existing Default or Event of Default may be waived with the consent of
the Holders outstanding. Without notice to or the consent of any Holder, the
Indenture or the Securities may be amended or supplemented to cure any
ambiguity, omission, defect or inconsistency, to provide for uncertificated
Securities in addition to certificated Securities, to comply with Sections 5.01
and 10.07 of the Indenture or to make any change that does not adversely affect
the rights of any Holder.

            15. Defaults and Remedies. An Event of Default includes the
occurrence of any or the following: default in payment of the principal of or
any premium on the Securities; default for 30 days in payment of interest;
failure by the Company for 90 days after notice to it to comply with any of its
other agreements in the Indenture or the Securities; and certain events of
bankruptcy or insolvency. If any Event of Default occurs and is continuing, the
Trustee or the Holders of at least 25% in aggregate principal amount of the
Securities then outstanding may declare all the Securities to be due and
payable. Holders may not enforce the Indenture or the Securities except as
provided in the Indenture. The Trustee may require indemnity satisfactory to it
before it enforces the Indenture or the Securities. Subject to certain
limitations, Holders of a majority in principal amount of the Securities then
outstanding may direct the Trustee in its exercise of any trust or power. The
Trustee may withhold from Holders notice of any continuing Default or Event of
Default (except a Default or Event of Default in payment of principal or
interest) if it determines that withholding notice is in their interests. The
Company must furnish an annual compliance certificate to the Trustee.

            16. Registration Rights. The Holders are entitled to shelf
registration rights as set forth in the Registration Rights Agreement. The
Holders shall be entitled to receive liquidated damages in certain
circumstances, all as set forth in the Registration Rights Agreement.

            17. Trustee Dealings with Company. The Trustee under the Indenture,
or any banking institution serving as successor Trustee thereunder, in its
individual or any other capacity, may make loans to, accept deposits from, and
perform services for the Company or its Affiliates, and may otherwise deal with
the Company or its Affiliates, as if it were not Trustee.

            18. No Recourse Against Others. No past, present or future director,
officer, employee or stockholder, as such, of the Company shall have any
liability for any obligations of the Company under the Securities or the
Indenture or for any claim based on, in respect of or by reason of such
obligations or their creation. Each Holder by accepting a Security waives and
releases all such liability. The waiver and release are part of the
consideration for the issue of the Securities.

            19. Authentication. This Security shall not be valid until
authenticated by the manual signature of the Trustee or an authenticating agent.
<PAGE>

            20. Abbreviations. Customary abbreviations may be used in the name
of a Holder or an assignee, such as: TEN COM (= tenants in common), TEN ENT (=
tenants by the entirety), JT TEN (= joint tenants with right of survivorship and
not as tenants in common), CUST (= Custodian), and U/G/M/A (Uniform Gifts to
Minors Act).

            THE COMPANY WILL FURNISH TO ANY SECURITYHOLDER UPON WRITTEN REQUEST
AND WITHOUT CHARGE A COPY OF THE INDENTURE. REQUESTS MAY BE MADE TO:

                      ALEXION PHARMACEUTICALS, INC.
                      25 SCIENCE PARK
                      NEW HAVEN, CONNECTICUT 06511
                      ATTENTION: PRESIDENT
<PAGE>

                              [FORM OF ASSIGNMENT]

I or we assign to

PLEASE INSERT SOCIAL SECURITY OR
OTHER IDENTIFYING NUMBER

_________________________________________________

________________________________________________________________________________
(please print or type name and address)

________________________________________________________________________________

________________________________________________________________________________
the within Security and all rights thereunder, and hereby irrevocably
constitutes and appoints

________________________________________________________________________________
attorney to transfer the Security on the books of the Company with full power
of substitution in the premises.

Dated:_____________________________     ________________________________________
                                        NOTICE: The signature on this assignment
                                        must correspond with the name as it
                                        appears upon the face of the within
                                        Security in every particular without
                                        alteration or enlargement or any change
                                        whatsoever and be guaranteed by the
                                        endorser's bank or broker.

Signature Guarantee:____________________________________________________________

            (Signatures must be guaranteed by an "eligible guarantor
institution" meeting the requirements of the Registrar, which requirements
include membership or participation in the Security Transfer Agent Medallion
Program ("STAMP") or such other "signature guarantee program" as may be
determined by the Registrar in addition to, or in substitution for, STAMP, all
in accordance with the Securities Exchange Act of 1934, as amended.)

            In connection with any transfer of this Security occurring prior to
the date which is the earlier of (i) the date of the declaration by the
Commission of the effectiveness of a registration statement under the Securities
Act of 1933, as amended (the "Securities Act") covering resales of this Security
(which effectiveness shall have been suspended or terminated at the date of the
transfer) and (ii) March 7, 2002 the undersigned confirms that
<PAGE>

it has not utilized any general solicitation or general advertising in
connection with transfer:

                                   [Check One]

(1) _____   to the Company or a subsidiary thereof; or

(2) _____   pursuant to and in compliance with Rule 144A under the Securities
            Act of 1933, as amended; or

(3) _____   to an institutional "accredited investor" (as defined in Rule
            501(a)(1), (2), (3) or (7) under the Securities Act of 1933, as
            amended) that has furnished to the Trustee a signed letter
            containing certain representations and agreements (the form of which
            letter can be obtained from the Trustee); or

(4) _____   outside the United States to a "foreign purchaser" in compliance
            with Rule 904 of Regulation S under the Securities Act of 1933, as
            amended; or

(5) _____   pursuant to the exemption from registration provided by Rule 144
            under the Securities Act of 1933, as amended; or

(6) _____   pursuant to an effective registration statement under the Securities
            Act of 1933, as amended; or

(7) _____   pursuant to another available exemption from the registration
            statement requirements of the Securities Act of 1933, as amended.

and unless the box below is checked, the undersigned confirms that such Security
is not being transferred to an "affiliate" of the Company as defined in Rule 144
under the Securities Act of 1933, as amended (an "Affiliate"):

            |_| The transferee is an Affiliate of the Company.

(If the Security is transferred to an Affiliate, the restrictive legend must
remain on the Security for two years following the date of the transfer).

            Unless one of the items is checked, the Trustee will refuse to
register any of the Securities evidenced by this certificate in the name of any
Person other than the registered Holder thereof; provided, however, that if item
(3),(4),(5) or (7) is checked, the Company or the Trustee may require, prior to
registering any such transfer of the Securities, in their sole discretion, such
written legal opinions, certifications (including an investment letter in the
case of box (3) or (4)) and other information as the Trustee or the Company have
reasonably requested to confirm that such transfer is being made pursuant to an
exemption from, or in a transaction not subject to, the registration
requirements of the Securities Act of 1933, as amended.
<PAGE>

            If none of the foregoing items are checked, the Trustee or Registrar
shall not be obligated to register this Security in the name of any Person other
than the Holder hereof unless and until the conditions to any such transfer of
registration set forth herein and in Section 2.16 of the Indenture shall have
been satisfied.

Dated: ___________________________      Signed:_________________________________
                                              (Sign exactly as name appears on
                                              the other side of this Security)

Signature Guarantee:____________________________________________________________

TO BE COMPLETED BY PURCHASER IF (2) ABOVE IS CHECKED

            The undersigned represents and warrants that it is purchasing this
Security for its own account or an account with respect to which it exercises
sole investment discretion and that it and any such account is a "qualified
institutional buyer" within the meaning of Rule 144A under the Securities Act of
1933, as amended, and is aware that the sale to it is being made in reliance on
Rule 144A and acknowledges that it has received such information regarding the
Company as the undersigned has requested pursuant to Rule 144A or has
determined transferor is relying upon the undersigned's foregoing
representations in order to claim the exemption from registration provided by
Rule 144A.

Dated: ____________________________     ________________________________________
                                        NOTICE: To be executed by an
                                                executive officer
<PAGE>

                                CONVERSION NOTICE

To convert this Security into Common Stock of the Company, check the box:

|_|

To convert only part of this Security, state the principal amount to be
converted (must be in multiples of $1,000):

$_______________________________________________________________________________

If you want the stock certificate made out in another person's name, fill in the
form below:

________________________________________________________________________________
(Insert other person's soc. sec. or tax I.D. no.)

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________
(Print or type other person's name, address and zip code)

________________________________________________________________________________

Date:______________ Signature(s): ___________________________________

                             ___________________________________________________
                             (Signatures must be guaranteed by an "eligible
                             guarantor institution" meeting the requirements of
                             the Registrar, which requirements include
                             membership or participation in the Security
                             Transfer Agent Medallion Program ("STAMP") or such
                             other "signature guarantee program" as may be
                             determined by the Registrar in addition to, or in
                             substitution for, STAMP, all in accordance with the
                             Securities Exchange Act of 1934, as amended.)
<PAGE>

Signature(s) guaranteed by: ____________________________________________________
                            (Signatures must be guaranteed by an "eligible
                            guarantor institution" meeting the requirements of
                            the Registrar, which requirements include membership
                            or participation in the Security Transfer Agent
                            Medallion Program ("STAMP") or such other "signature
                            guarantee program" as may be determined by the
                            Registrar in addition to, or in substitution for,
                            STAMP, all in accordance with the Securities
                            Exchange Act of 1934, as amended.)
<PAGE>

                    OPTION OF HOLDER TO ELECT PURCHASE NOTICE

            If you want to elect to have this Security purchased by the Company
pursuant to Section 3.07 of the Indenture, check the box: |_|

            If you want to elect to have only part of this Security purchased by
the Company pursuant to Section 3.07 of the Indenture, state the principal
amount:

                  $___________________________________________
                       (in an integral multiple of $1,000)

Date:____________________               Signature(s): __________________________

                                        ________________________________________
                                        (Sign exactly as your name(s) appear(s)
                                        on the other side of this Security)

Signature(s) guaranteed by:             ________________________________________
                                        (Signatures must be guaranteed by an
                                        "eligible guarantor institution" meeting
                                        the requirements of the Registrar, which
                                        requirements include membership or
                                        participation in the Security Transfer
                                        Agent Medallion Program ("STAMP") or
                                        such other "signature guarantee program"
                                        as may be determined by the Registrar in
                                        addition to, or in substitution for,
                                        STAMP, all in accordance with the
                                        Securities Exchange Act of 1934, as
                                        amended.)

<PAGE>

            THIS SECURITY (OR ITS PREDECESSOR) WAS 0RIGINALLY ISSUED IN A
TRANSACTION EXEMPT FROM REGISTRATION UNDER THE UNITED STATES SECURITIES ACT OF
1933 (THE "SECURITIES ACT"), AND THIS SECURITY AND THE SHARES OF COMMON STOCK
ISSUABLE UPON CONVERSION HEREOF MAY NOT BE OFFERED, SOLD OR OTHERWISE
TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION
THEREFROM. EACH PURCHASER OF THIS SECURITY IS HEREBY NOTIFIED THAT THE SELLER OF
THIS SECURITY MAY BE RELYING ON THE EXEMPTION FROM THE PROVISIONS OF SECTION 5
OF THE SECURITIES ACT PROVIDED BY RULE 144A THEREUNDER.

            THE HOLDER OF THIS SECURITY AGREES FOR THE BENEFIT OF THE ISSUER
HEREOF THAT (A) THIS SECURITY AND THE SHARES OF COMMON STOCK ISSUABLE UPON
CONVERSION HEREOF MAY BE OFFERED, RESOLD, PLEDGED OR OTHERWISE TRANSFERRED, ONLY
(I) IN THE UNITED STATES TO A PERSON WHOM THE SELLER REASONABLY BELIEVES IS A
QUALIFIED INSTITUTIONAL BUYER (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT)
IN A TRANSACTION MEETING THE REQUIREMENTS OF RULE 144A, (II) PURSUANT TO AN
EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT PROVIDED BY RULE 144
THEREUNDER (IF AVAILABLE) OR (III) PURSUANT TO AN EFFECTIVE REGISTRATION
STATEMENT UNDER THE SECURITIES ACT, IN EACH OF CASES (I) THROUGH (III) IN
ACCORDANCE WITH ANY APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED
STATES, AND (B) THE HOLDER WILL, AND EACH SUBSEQUENT HOLDER IS REQUIRED TO,
NOTIFY ANY PURCHASER OF THIS SECURITY FROM IT OF THE RESALE RESTRICTIONS
REFERRED TO IN (A) ABOVE.

            THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE
INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITORY
OR A NOMINEE OF A DEPOSITORY OR A SUCCESSOR DEPOSITORY. THIS SECURITY IS NOT
EXCHANGEABLE FOR SECURITIES REGISTERED IN THE NAME OF A PERSON OTHER THAN THE
DEPOSITORY OR ITS NOMINEE EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE
INDENTURE, AND NO TRANSFER OF THIS SECURITY (OTHER THAN A TRANSFER OF THIS
SECURITY AS A WHOLE BY THE DEPOSITORY TO A NOMINEE OF THE DEPOSITORY OR BY A
NOMINEE OF THE DEPOSITORY TO THE DEPOSITORY OR ANOTHER NOMINEE OF THE
DEPOSITORY) MAY BE REGISTERED EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN
THE INDENTURE.

            UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE
OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE COMPANY
OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY
CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME
AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY
<PAGE>

PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN
AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR
VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED
OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS IN WHOLE, BUT
NOT IN PART, TO NOMINEES OF CEDE & CO. OR TO A SUCCESSOR THEREOF OR SUCH
SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL SECURITY SHALL BE
LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN
SECTION 2.16 OF THE INDENTURE.
<PAGE>

                                                           CUSIP No. U01409 AA 6
No. 002                                                               $9,450,000

                          ALEXION PHARMACEUTICALS, INC.

                 5 3/4% CONVERTIBLE SUBORDINATED NOTE DUE 2007

            ALEXION PHARMACEUTICALS, INC., a Delaware corporation (herein called
the "Company"), for value received, hereby promises to pay to Cede & Co. or
registered assigns, the principal sum of NINE MILLION FOUR HUNDRED AND FIFTY
THOUSAND Dollars on March 15, 2007, and to pay interest thereon as provided on
the reverse hereof on the principal sum, until the principal hereof and any
unpaid and accrued interest is paid or duly provided for. The right to payment
of principal, premium, if any, and interest is subordinated to the rights of
Senior Indebtedness as set forth in the Indenture referred to on the reverse
side hereof.

            Interest Payment Dates: March 15 and September 15, with the first
payment to be made on September 15, 2000.

Record Dates: March 1 and September 1.
<PAGE>

            IN WITNESS WHEREOF, ALEXION PHARMACEUTICALS, INC. has caused this
instrument to be duly signed.

                                        ALEXION PHARMACEUTICALS

                                        By: /s/ David Keiser
                                           -------------------------------------
                                           Name:
                                           Title:

                                        By: /s/ B.P. Luke
                                           -------------------------------------
                                           Name:
                                           Title:

Dated:March 8, 2000

TRUSTEE'S CERTIFICATE OF
  AUTHENTICATION

This is one of the Securities referred
to in the within-mentioned Indenture.

THE CHASE MANHATTAN BANK, as Trustee

By: /s/ Kathleen Perry
   --------------------------------
         Authorized Office
<PAGE>

                          ALEXION PHARMACEUTICALS, INC.

                  5 3/4% CONVERTIBLE SUBORDINATED NOTE DUE 2007

            1. Interest. Alexion Pharmaceuticals, Inc., a Delaware corporation
(the "Company"), promises to pay interest on the principal amount of this
Security at the rate per annum shown above. The Company will pay interest
semi-annually in arrears on March 15 and September 15 of each year, with the
first payment to be made on September 15, 2000. Interest on the Securities will
accrue on the principal amount from the most recent date to which interest has
been paid or duly provided for or, if no interest has been paid, from March 8,
2000. Interest will be computed on the basis of a 360-day year of twelve 30-day
months.

            2. Maturity. The Securities will mature on March 15, 2007 unless
earlier convened, redeemed or repurchased pursuant to the terms hereof and the
Indenture.

            3. Method of Payment. The Company will pay interest on the
Securities (except defaulted interest) to the Persons who are registered Holders
of Securities at the close of business on the record date set forth on the face
of this Security next preceding the applicable interest payment date except that
(i) interest payable upon redemption or repurchase, unless the date of
redemption or repurchase is an interest payment date, will be payable to the
Person to whom the principal is payable and (ii) in the case of any Security or
portion of any Security that is convened into Common Stock during the period
from, but excluding, a record date for any interest payment date to, but
excluding, that interest payment date either (A) if the Security, or portion of
the Security, has been called for redemption on a redemption date that occurs
during that period, or is to be repurchased on a Repurchase Date that occurs
during that period, the Company will not be required to pay interest on that
interest payment date in respect of any Security, or portion of any Security,
that is so redeemed or repurchased; or (B) if otherwise, any Security or portion
of any Security that is not called for redemption but is submitted for
conversion during that period must be accompanied by finds equal to the interest
payable on that interest payment date on the principal amount so convened.
Holders must surrender Securities to a Paying Agent to collect the principal
payments. The Company will pay the principal, premium, if any, and interest in
money of the United States that at the time of payment is legal tender.
Principal and interest may, at the Company's option, be paid either (i) by check
mailed to the address of the Person entitled to the interest as it appears in
the register kept by the Registrar (provided (a) payments to the Depository will
be made by wire transfer of immediately available funds to the account of the
Depository or its nominee and (b) a Holder with an aggregate principal amount of
Securities in excess of $10 million will, at the written election of the Holder,
filed on or before the relevant record date with the Trustee, be paid by wire
transfer in immediately available funds); or (ii) by transfer to an account
maintained by that Person located in the U.S.

<PAGE>

            4. Paying Agent, Registrar, Conversion Agent. Initially, The Chase
Manhattan Bank (the "Trustee") will act as Paying Agent, Registrar and
Conversion Agent. The Company may change any Paying Agent, Registrar or
Conversion Agent without notice. The Company may act in any such capacity.

            5. Indenture. The Company issued the Securities under an Indenture
dated as of March 8, 2000 (the "Indenture") between the Company and the Trustee.
The terms of the Securities include those stated in the Indenture and those made
part of the Indenture by reference to the Trust Indenture Act of 1939 (15 U.S.
Code ss.ss. 77aaa-77bbbb) (the "Act") as in effect on the date of the Indenture.
The Securities are subject to all such terms, and Holders are referred to the
Indenture and the Act for a statement of such terms. The Securities are general
unsecured subordinated obligations of the Company limited to a maximum of
$120,000,000 aggregate principal amount (plus such additional amount (up to an
aggregate of $30,000,000) purchased by the Initial Purchasers pursuant to the
option described in Section 2.02), except as otherwise provided in the Indenture
(except for Securities issued in substitution for destroyed, mutilated, lost or
stolen Securities). Terms used herein which are defined in the Indenture have
the meanings assigned to them in the Indenture.

            6. Optional Redemption by the Company. At any time on or after March
20, 2003, the Company may redeem the Securities on at least 30 days' notice as a
whole or, from time to time, in part at the following prices, expressed as a
percentage of the principal amount, together with accrued interest to, but
excluding, the date fixed for redemption:

                                                                    Redemption
Period                                                                Price
------                                                              ----------

Beginning March 20, 2003 and ending on March 14, 2004                103.286%
Beginning March 15, 2004 and ending on March 14, 2005                102.464%
Beginning March 15, 2005 and ending on March 14, 2006                101.643%
Beginning March 15, 2006 and ending on March 14, 2007                100.822%

and 100% on March 15, 2007. Any accrued interest becoming due on the date fixed
for redemption will be payable to the holders of record on the relevant record
date of the Securities being redeemed.

            7. Notice of Redemption. Notice of redemption pursuant to paragraph
6 will be mailed at least 30 days before the redemption date to each Holder of
Securities to be redeemed at its registered address. Securities in denominations
larger than $1,000 principal amount may be redeemed in part but only in whole
multiples of $1,000 principal amount. On and after the redemption date interest
ceases to accrue on Securities or portions of them called for redemption.

            8. Repurchase at Option of Holder. Pursuant to Section 3.07 of the
Indenture within 15 days after a Repurchase Event occurs, the Company is
required to give
<PAGE>

notice of the Repurchase Event to the Holders. Each Holder has the right, at its
option, to require the Company to repurchase all or any portion of the
Securities 40 days after the notice of repurchase event is mailed. The
Repurchase Price will be 105% of the principal amount of the Securities
submitted for repurchase, plus accrued and unpaid interest to, but excluding,
the Repurchase Date. If a Repurchase Date is an interest payment date, then the
interest payable on that date will be paid to the holder of record on the
relevant record date. Subject to the conditions of Section 3.07 of the
Indenture, the Company, at its option, instead of paying the Repurchase Price in
cash, may pay the Repurchase Price in Common Stock, valued at 95% of the average
of the Closing Prices for the five Trading Days immediately before and including
the third Trading Day preceding the Repurchase Date.

            9. Conversion. A Holder of a Security may convert the principal of
such Security into Common Stock at any time after the date of original issuance
of the Security to the close of business on the business day prior to March 15,
2007, or (x) if the Security is called for redemption by the Company, the Holder
may convert it at any time before the close of business on the date that is one
business day before the date fixed for such redemption, or (y) if the Security
is to be repurchased by the Company pursuant to paragraph 8 hereof, the Holder
may convert it at any time before the close of business on the date that is one
business day before the date fixed for such repurchase. The initial Conversion
Price is $106.425 per share of Common Stock, subject to adjustment in certain
circumstances as set forth in Section 10.06 of the Indenture. To determine the
number of shares issuable upon conversion of a Security, divide the principal
amount to be converted by the Conversion Price in effect on the conversion date
and round the result to the nearest 1/100th share. The Company is not required
to issue fractional shares of Common Stock upon conversion and, instead, will
pay a cash amount as provided in Section 10.03 of the Indenture. Except as
provided in Article Ten of the Indenture, no payment or adjustment for the
principal of, premium, if any, interest on or liquidated damages with respect
to, the Securities or for dividends on any Common Stock will be made. If a
Holder surrenders a Security for conversion between the record date for the
payment of interest and the next interest payment date, such Security, when
surrendered for conversion, must be accompanied by payment of an amount equal to
the interest thereon which the registered Holder on such record date is to
receive. A Security which the Holder has elected to be repurchased may be
converted only if the Holder withdraws its election to have such Security
repurchased in accordance with the terms of the Indenture before the close of
business on the business day prior to the Repurchase Date.

            To convert a Security a Holder must (1) complete and sign the
Conversion Notice, with appropriate signature guarantee, on the back of the
Security, (2) surrender the Security to a Conversion Agent, (3) furnish
appropriate endorsements and transfer documents if required by the Registrar or
Conversion Agent, (4) pay the amount of interest, if any, the Holder may be paid
as provided in the last sentence of the above paragraph and (5) pay any transfer
or similar tax if required. A Holder may convert a portion of a Security if the
portion is $1,000 principal amount or a whole multiple of $ 1,000 principal
amount.
<PAGE>

            Any shares issued upon conversion of a Security shall bear the
Private Placement Legend until after the second anniversary of the later of the
issue date for the Securities and the last date on which the Company or any
Affiliate of the Company was the owner of such shares or the Security (or any
predecessor security) from which such shares were converted (or such shorter
period of time as permitted by Rule 144(k) under the Securities Act or any
successor provision thereunder) (or such longer period of time as may be
required under the Securities Act or applicable state securities laws as set
forth in the Opinion of Counsel delivered to the Conversion Agent, unless
otherwise agreed by the Company and the Holder thereof).

            10. Subordination. The Securities are subordinated in right of
payment, in the manner and to the extent set forth in the Indenture, to the
prior payment in full of all Senior Indebtedness. Each Holder by accepting a
Security agrees to such subordination and authorizes the Trustee to give it
effect.

            11. Denominations, Transfer, Exchange. The Securities are in
registered form without coupons in denominations of $1,000 principal amount and
whole multiples of $1,000 principal amount. The transfer of Securities may be
registered and Securities may be exchanged as provided in the Indenture. The
Registrar may require a Holder, among other things, to furnish appropriate
endorsements and transfer documents. No service charge shall be made for any
such registration of transfer or exchange, but the Company may require payment
of a sum sufficient to cover any tax or other governmental charge payable in
connection therewith. The Registrar need not exchange or register the transfer
of any Security selected for redemption in whole or in part. Also, it need not
exchange or register the transfer of any Securities for a period of 15 days
before the mailing of a notice of redemption of the Securities selected to be
redeemed.

            12. Persons Deemed Owners. The registered Holder of a Security may
be treated as the owner of such Security for all purposes.

            13. Merger or Consolidation. The Company shall not consolidate with,
or merge into, or transfer or lease all or substantially all of its assets to,
any Person unless, among other things, the Person is organized under the laws of
the United States, any State thereof or the District of Columbia and such Person
assumes by supplemental indenture all the obligations of the Company under the
Securities, the Indenture and the Registration Rights Agreement and after giving
effect to the transaction no Default or Event of Default exists.

            Notwithstanding the foregoing, any subsidiary of the Company may
consolidate with, merge into or transfer all or part of its properties and
assets to the Company or any other subsidiary or subsidiaries of the Company.

            14. Amendments, Supplements and Waivers. Subject to certain
exceptions, the Indenture or the Securities may be amended or supplemented with
the consent of the Holders of at least a majority in aggregate principal amount
of the Securities then outstanding,

<PAGE>

and any existing Default or Event of Default may be waived with the consent of
the Holders of a majority in aggregate principal amount of the Securities then
outstanding. Without notice to or the consent of any Holder, the Indenture or
the Securities may be amended or supplemented to cure any ambiguity, omission,
defect or inconsistency, to provide for uncertificated Securities in addition to
certificated Securities, to comply with Sections 5.01 and 10.07 of the Indenture
or to make any change that does not adversely affect the rights of any Holder.

            15. Defaults and Remedies. An Event of Default includes the
occurrence of any or the following: default in payment of the principal of or
any premium on the Securities; default for 30 days in payment of interest;
failure by the Company for 90 days after notice to it to comply with any of its
other agreements in the Indenture or the Securities; and certain events of
bankruptcy or insolvency. If any Event of Default occurs and is continuing, the
Trustee or the Holders of at least 25% in aggregate principal amount of the
Securities then outstanding may declare all the Securities to be due and
payable. Holders may not enforce the Indenture or the Securities except as
provided in the Indenture. The Trustee may require indemnity satisfactory to it
before it enforces the Indenture or the Securities. Subject to certain
limitations, Holders of a majority in principal amount of the Securities then
outstanding may direct the Trustee in its exercise of any trust or power. The
Trustee may withhold from Holders notice of any continuing Default or Event of
Default (except a Default or Event of Default in payment of principal or
interest) if it determines that withholding notice is in their interests. The
Company must furnish an annual compliance certificate to the Trustee.

            16. Registration Rights. The Holders are entitled to shelf
registration rights as set forth in the Registration Rights Agreement. The
Holders shall be entitled to receive liquidated damages in certain
circumstances, all as set forth in the Registration Rights Agreement.

            17. Trustee Dealings with Company. The Trustee under the Indenture,
or any banking institution serving as successor Trustee thereunder, in its
individual or any other capacity, may make loans to, accept deposits from, and
perform services for the Company or its Affiliates, and may otherwise deal with
the Company or its Affiliates, as if it were not Trustee.

            18. No Recourse Against Others. No past, present or future director,
officer, employee or stockholder, as such, of the Company shall have any
liability for any obligations of the Company under the Securities or the
Indenture or for any claim based on, in respect of or by reason of such
obligations or their creation. Each Holder by accepting a Security waives and
releases all such liability. The waiver and release are part of the
consideration for the issue of the Securities.

            19. Authentication. This Security shall not be valid until
authenticated by the manual signature of the Trustee or an authenticating agent.

<PAGE>

            20. Abbreviations. Customary abbreviations may be used in the name
of a Holder or an assignee, such as: TEN COM (= tenants in common), TEN ENT (=
tenants by the entirety), JT TEN (= joint tenants with right of survivorship and
not as tenants in common), CUST (= Custodian), and U/G/M/A (Uniform Gifts to
Minors Act).

            THE COMPANY WILL FURNISH TO ANY SECURITYHOLDER UPON WRITTEN REQUEST
AND WITHOUT CHARGE A COPY OF THE INDENTURE. REQUESTS MAY BE MADE TO:

                      ALEXION PHARMACEUTICALS, INC.
                      25 SCIENCE PARK
                      NEW HAVEN, CONNECTICUT 06511
                      ATTENTION: PRESIDENT
<PAGE>

                              [FORM OF ASSIGNMENT]

I or we assign to

PLEASE INSERT SOCIAL SECURITY OR
OTHER IDENTIFYING NUMBER

_________________________________________________

________________________________________________________________________________
(please print or type name and address)

________________________________________________________________________________

________________________________________________________________________________
the within Security and all rights thereunder, and hereby irrevocably
constitutes and appoints

________________________________________________________________________________
attorney to transfer the Security on the books of the Company with full power
of substitution in the premises.

Dated:_____________________________     ________________________________________
                                        NOTICE: The signature on this assignment
                                        must correspond with the name as it
                                        appears upon the face of the within
                                        Security in every particular without
                                        alteration or enlargement or any change
                                        whatsoever and be guaranteed by the
                                        endorser's bank or broker.

Signature Guarantee:____________________________________________________________

            (Signatures must be guaranteed by an "eligible guarantor
institution" meeting the requirements of the Registrar, which requirements
include membership or participation in the Security Transfer Agent Medallion
Program ("STAMP") or such other "signature guarantee program" as may be
determined by the Registrar in addition to, or in substitution for, STAMP, all
in accordance with the Securities Exchange Act of 1934, as amended.)

            In connection with any transfer of this Security occurring prior to
the date which is the earlier of (i) the date of the declaration by the
Commission of the effectiveness of a registration statement under the Securities
Act of 1933, as amended (the "Securities Act") covering resales of this Security
(which effectiveness shall have been suspended or terminated at the date of the
transfer) and (ii) March 7, 2002 the undersigned confirms that
<PAGE>

it has not utilized any general solicitation or general advertising in
connection with transfer:

                                   [Check One]

(1) _____   to the Company or a subsidiary thereof; or

(2) _____   pursuant to and in compliance with Rule 144A under the Securities
            Act of 1933, as amended; or

(3) _____   to an institutional "accredited investor" (as defined in Rule
            501(a)(1), (2), (3) or (7) under the Securities Act of 1933, as
            amended) that has furnished to the Trustee a signed letter
            containing certain representations and agreements (the form of which
            letter can be obtained from the Trustee); or

(4) _____   outside the United States to a "foreign purchaser" in compliance
            with Rule 904 of Regulation S under the Securities Act of 1933, as
            amended; or

(5) _____   pursuant to the exemption from registration provided by Rule 144
            under the Securities Act of 1933, as amended; or

(6) _____   pursuant to an effective registration statement under the Securities
            Act of 1933, as amended; or

(7) _____   pursuant to another available exemption from the registration
            statement requirements of the Securities Act of 1933, as amended.

and unless the box below is checked, the undersigned confirms that such Security
is not being transferred to an "affiliate" of the Company as defined in Rule 144
under the Securities Act of 1933, as amended (an "Affiliate"):

            |_| The transferee is an Affiliate of the Company.

(If the Security is transferred to an Affiliate, the restrictive legend must
remain on the Security for two years following the date of the transfer).

            Unless one of the items is checked, the Trustee will refuse to
register any of the Securities evidenced by this certificate in the name of any
Person other than the registered Holder thereof; provided, however, that if item
(3),(4),(5) or (7) is checked, the Company or the Trustee may require, prior to
registering any such transfer of the Securities, in their sole discretion, such
written legal opinions, certifications (including an investment letter in the
case of box (3) or (4)) and other information as the Trustee or the Company have
reasonably requested to confirm that such transfer is being made pursuant to an
exemption from, or in a transaction not subject to, the registration
requirements of the Securities Act of 1933, as amended.
<PAGE>

            If none of the foregoing items are checked, the Trustee or Registrar
shall not be obligated to register this Security in the name of any Person other
than the Holder hereof unless and until the conditions to any such transfer of
registration set forth herein and in Section 2.16 of the Indenture shall have
been satisfied.

Dated: ___________________________      Signed:_________________________________
                                              (Sign exactly as name appears on
                                              the other side of this Security)

Signature Guarantee:____________________________________________________________

TO BE COMPLETED BY PURCHASER IF (2) ABOVE IS CHECKED

            The undersigned represents and warrants that it is purchasing this
Security for its own account or an account with respect to which it exercises
sole investment discretion and that it and any such account is a "qualified
institutional buyer" within the meaning of Rule 144A under the Securities Act of
1933, as amended, and is aware that the sale to it is being made in reliance on
Rule 144A and acknowledges that it has received such information regarding the
Company as the undersigned has requested pursuant to Rule 144A or has
determined transferor is relying upon the undersigned's foregoing
representations in order to claim the exemption from registration provided by
Rule 144A.

Dated: ____________________________     ________________________________________
                                        NOTICE: To be executed by an
                                                executive officer
<PAGE>

                                CONVERSION NOTICE

To convert this Security into Common Stock of the Company, check the box:

|_|

To convert only part of this Security, state the principal amount to be
converted (must be in multiples of $1,000):

$_______________________________________________________________________________

If you want the stock certificate made out in another person's name, fill in the
form below:

________________________________________________________________________________
(Insert other person's soc. sec. or tax I.D. no.)

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________
(Print or type other person's name, address and zip code)

Date:______________ Signature(s): ___________________________________

                             ___________________________________________________
                             (Signatures must be guaranteed by an "eligible
                             guarantor institution" meeting the requirements of
                             the Registrar, which requirements include
                             membership or participation in the Security
                             Transfer Agent Medallion Program ("STAMP") or such
                             other "signature guarantee program" as may be
                             determined by the Registrar in addition to, or in
                             substitution for, STAMP, all in accordance with the
                             Securities Exchange Act of 1934, as amended.)
<PAGE>

Signature(s) guaranteed by: ____________________________________________________
                            (Signatures must be guaranteed by an "eligible
                            guarantor institution" meeting the requirements of
                            the Registrar, which requirements include membership
                            or participation in the Security Transfer Agent
                            Medallion Program ("STAMP") or such other "signature
                            guarantee program" as may be determined by the
                            Registrar in addition to, or in substitution for,
                            STAMP, all in accordance with the Securities
                            Exchange Act of 1934, as amended.)
<PAGE>

                    OPTION OF HOLDER TO ELECT PURCHASE NOTICE

            If you want to elect to have this Security purchased by the
Company pursuant to Section 3.07 of the Indenture, check the box: |_|

            If you want to elect to have only part of this Security purchased by
the Company pursuant to Section 3.07 of the Indenture, state the principal
amount:

                  $___________________________________________
                       (in an integral multiple of $1,000)

Date:____________________               Signature(s): __________________________

                                        ________________________________________
                                        (Sign exactly as your name(s) appear(s)
                                        on the other side of this Security)

Signature(s) guaranteed by:             ________________________________________
                                        (Signatures must be guaranteed by an
                                        "eligible guarantor institution" meeting
                                        the requirements of the Registrar, which
                                        requirements include membership or
                                        participation in the Security Transfer
                                        Agent Medallion Program ("STAMP") or
                                        such other "signature guarantee program"
                                        as may be determined by the Registrar in
                                        addition to, or in substitution for,
                                        STAMP, all in accordance with the
                                        Securities Exchange Act of 1934, as
                                        amended.)<PAGE>
                                                                    Exhibit 10.2

               =================================================

                                      LEASE

                               WE KNOTTER, L.L.C.
                                   (LANDLORD)

                                       AND

                          ALEXION PHARMACEUTICALS, INC.
                                    (TENANT)

                               DATED: MAY __, 2000

               =================================================
<PAGE>

                                     LEASE

      AGREEMENT OF LEASE dated as of the ___ day of May, 2000 between WE
KNOTTER, L.L.C., a Delaware limited liability company, with an office at c/o
Winstanley Enterprises, LLC, 150 Baker Street Extension, Suite 303, Concord
Massachusetts 01742 ("Landlord"), and ALEXION PHARMACEUTICALS, INC., a Delaware
corporation with offices at 25 Science Park, Suite 360, New Haven, Connecticut
06511 ("Tenant").

                                   WITNESSETH:

      Landlord and Tenant hereby covenant and agree as follows:

                              ARTICLE I DEFINITIONS

      For the purposes of this Lease, unless the context otherwise requires:

      1.1 "Governmental Authority" shall mean any federal, state, county,
municipal or local government and all departments, commissions, boards, bureaus
and offices thereof having or claiming jurisdiction over the "Premises" (as
defined below).

      1.2 "Land" shall mean the parcel of land situated in the County of New
Haven, State of Connecticut and Town of Cheshire, known as 350 Knotter Drive,
being more particularly described on Exhibit I attached hereto.

      1.3 "Lease Year" shall mean every period of twelve (12) consecutive months
during the term of this Lease commencing on January first (1st) and terminating
on December thirty-first (31st), except that the first Lease Year shall mean the
period from the Commencement Date through December 31st of such calendar year
and the last Lease year shall end on the Expiration Date (as such terms are
defined in the Lease).

      1.4 "Tenant's Property" shall mean all of Tenant's personal property and
all fixtures, improvements, additions, and other property installed at the sole
expense of Tenant with respect to which Tenant has not been granted any credit
or allowance by Landlord, whether any such replacement is made at Tenant's
expense or otherwise. Tenant's Property shall include personal property that can
easily be removed, including, without limitation, items described on Exhibit J
attached hereto (and including enhancements to and replacements of such items
which shall be identified by Tenant delivering to Landlord, on an annual basis,
an update of the list of items), but shall not include any other fixtures or
items of personal property which are permanently affixed to the Premises or the
Building systems.

      1.5 "Superior Mortgages" shall have the meaning given in Section 20.1.

                        ARTICLE 2 DEMISE; PREMISES; TERM

      2.1 Landlord hereby leases to Tenant, and Tenant hereby hires from
Landlord, the premises hereinafter described ("Premises"), consisting of
approximately 81,890 rentable square feet in the building situated at 350
Knotter Drive, Cheshire, Connecticut (the "Building"), as shown on the plan
attached hereto as Exhibit A (the "Plan"), together with the non-exclusive right
to use the common areas
<PAGE>

for their intended purposes, for the term hereinafter stated, for the rents
hereinafter reserved, and upon and subject to the terms, restrictions and
reservations hereinafter provided. The common areas of the Land and Building
include the portions thereof designated by Landlord for the common use of
tenants (including Tenant) and others, such as sidewalks, parking areas,
grounds, lobby areas, boiler and mechanical rooms and areas. Landlord shall
permit Tenant to have access to the common areas of the Building for installing
and maintaining specific services or utilities designated for and/or dedicated
to the specific use of Tenant (that is not with respect to shared services or
utilities) with Landlord's prior consent (which consent shall not be
unreasonably withheld). In the event and to the extent Landlord, Arch (as
defined below) or any other tenant requires or has been granted access and right
to use the common areas shown on Exhibit A as the boiler rooms, then such access
shall be by the use of the exterior doors, except in the event of an emergency,
when, if necessary to address the emergency, access may be had in the most
expedient manner. Tenant has advised Landlord that it has a training program in
place for persons requiring access to the Premises. Landlord covenants and
agrees that it will require its employees and property managers to attend such
program and it will cause other tenants at the Building moving into the Building
after the Commencement Date to have such of their employees as may require
access to Tenant's Premises to attend such training program. The Landlord has
notified Arch that Tenant has required that the ability of other to access its
Premises be conditioned upon such people attending Tenant's training program.
Arch has represented to the Landlord that it will cause such of its employees as
may require access to the Premises to attend such training program.

      2.2 The Premises are located in the Building, substantially as shown on
the floor plan(s) annexed as Exhibit A, and shall include all fixtures,
equipment, improvements and appurtenances which, at the commencement of the Term
or at any time during the Term, are attached thereto or installed therein, other
than Tenant's Property.

      2.3 The Premises are leased for a term ("Term") which shall commence on
the date that Arch Chemicals, Inc. ("Arch") shall vacate the Premises (including
removal by Arch of all of the property set forth on Exhibit K, as more
particularly set forth below) and Landlord delivers the Premises to Tenant free
of any right or claim of Arch or any other occupant (except as otherwise set
forth herein) (such date, the "Commencement Date"). It is anticipated that Arch
will vacate the Premises on or before August 14, 2000. Tenant acknowledges that
during the period prior to the Commencement Date (such period, the "Arch
Move-Out Period"), Arch will be relocating from the area of the Premises to the
area demised to it, as shown on the Plan. In the event the Commencement Date has
not occurred on or before October 1, 2000 then, for each day of delay after
October 1, 2000, Tenant will be granted one additional day of abatement of Fixed
Rent and Additional Rent beyond the dates specified in Exhibit B. The Term shall
expire on the last day of the 126th month of the Term ("Expiration Date") unless
the Term shall be extended or sooner terminated pursuant to any of the terms,
covenants or conditions of this Lease or pursuant to law. The parties will
promptly after the Commencement Date execute a notice of Commencement in the
form attached hereto as Exhibit F. Tenant will be granted access to the Premises
during the Arch Move-out Period provided that Tenant's presence doesn't
interfere with (x) Arch's build-out of and relocation to its premises, (y) the
day to day operations of Arch or (z) the performance by Landlord of Landlord's
Work (as defined below) Tenant's access to and use of the Premises will be
subject to the terms and conditions of this Lease (except that no rent or
additional Rent shall be payable), including without limitation, the provisions
of Article 17 and the obligation that Tenant deliver evidence of insurance as
required by Article 7. Tenant may present to Landlord, from time to time, work
plans (each of which shall include the scope, scheduling and method of work) for
Landlord's agreement that the work, if performed in accordance with the plan,
will not present an issue pursuant to any of clauses (x), (y) or (z) above. Arch
has advised Landlord that it anticipates vacating the area of Tenant's

                                       2
<PAGE>

proposed vivarium (as shown on Exhibit L attached hereto) on or about June 9,
2000. Landlord agrees that Tenant may, upon the vacating by Arch of such area,
in accordance with the terms of this Lease, have access to and use of such area.

      2.4 Tenant acknowledges that Arch shall, promptly after the Commencement
Date, continue to have access to an area shown on Exhibit A as the Less Than 90
Day Storage Facility to permit Arch to "close" the same in accordance with
applicable laws. Pursuant to the lease between Landlord and Arch dated March 15,
2000 (the "Arch Lease"), Arch has agreed upon substantial completion of a new
less than 90 Day hazardous waste storage facility which is being constructed by
Landlord (which construction is anticipated to be completed on or before August
14, 2000) to promptly vacate and proceed to closure in accordance of all
applicable law of the Less Than 90 Day Storage Facility referenced above. The
Arch Lease further provides that, to the extent feasible, and subject to any
applicable requirement of any Governmental Authority, from and after the
expiration of the Arch Move-Out Period, Arch will access the aforesaid Less Than
90 Day Storage Facility through the outside door. Arch's access to the Less than
90 Day Storage Facility and of other areas not demised to it under the Arch
Lease is governed by and subject to the terms and conditions of that certain
Agreement between Landlord and Arch dated March 15, 2000. Landlord will promptly
take all such action as may be necessary to cause Arch to comply fully with the
March 15, 2000 agreement and the Arch Lease, provided this undertaking as to the
Arch Lease applies only insofar as the Arch Lease relates to Arch's closure and
vacating of the existing Less Than 90 Day Storage Facility. At such time as the
closure of the Less Than 90 Day Storage Facility has been completed, Landlord
shall deliver or cause to be delivered to Tenant a certification or report to
evidence the same, which indicates that closure has been accomplished in full
and in accordance with all applicable laws.

      2.5 In connection with the performance of Landlord's Work and of Tenant's
Initial Alterations, as defined below, Landlord and Tenant shall coordinate the
preparation of plans and, to the extent feasible, the obtaining of necessary
permits and approvals from the applicable Governmental Authorities and from
F.I.P. Corporation, or its successor, as the declarant under those declarations
of record in the Town of Cheshire affecting the Premises, copies of which
declarations are attached hereto as Exhibit M.

              ARTICLE 3 OCCUPANCY OF THE PREMISES, LANDLORD'S WORK
                                AND TENANT'S WORK

      3.1 Tenant represents that Tenant has inspected and is familiar with the
Premises and the Building and is thoroughly acquainted with their condition and
takes the Premises "as is", except (i) that the Premises will be delivered
"broom clean" and (ii) for the completion of Landlord's Work, as defined herein,
and the taking of possession of the premises by Tenant shall be conclusive at
the time possession was taken by Tenant. Arch has covenanted that it will, in
vacating the Premises, remove only those items of personal property set forth on
Exhibit K attached hereto. All items other than those set forth on Exhibit K
present in the Premises as of that date of Tenant's inspection of the Premises,
that is, as of April 18, 2000, will be surrendered by Arch and, as set forth in
Section 2.2 above, be included in and constitute a part of the Premises. Except
as expressly set forth herein, neither Landlord nor Landlord's agents have made
any representations or promises with respect to the condition of the Building,
the Premises or the Land, and no rights easements or licenses are acquired by
Tenant by implication or otherwise except as expressly set forth in this Lease.

                                       3
<PAGE>

      3.2 Landlord shall, at Landlord's expense, and pursuant to the provisions
of Exhibit E, attached hereto, perform the Landlord's Work. Landlord's Work
shall be performed in a good and workmanlike manner, using materials of a
quality not less than those now present in the Building (but in any event of no
less than first quality unused material). Any of Landlord's Work not completed
during the Arch Move-Out Period will be performed in a manner so as to minimize
disruption of Tenant's business.

      3.3 The Tenant shall complete certain work (the "Initial Alterations")
subject to and in accordance with the provisions of the Work Letter attached
hereto as Exhibit D.

      3.4 To the extent Tenant draws upon the Allowance furnished by Landlord
(as set forth on Exhibit D), then the Allowance amount utilized by Tenant shall
be repaid by Tenant by amortizing the amount over the initial Term of the Lease
(commencing on the 1st day of the seventh month of the Term) with interest
thereon at the rate of 11% per annum and the amortized Allowance (including
interest) shall be added to Fixed Rent as identified and set forth in Section 4
and Exhibit B hereof. Alternatively, Tenant may elect to repay the amount of the
Allowance utilized in a lump sum, together with interest thereon from the
date(s) of disbursement through the date of repayment at 11% per annum provided
that the full repayment is made prior to the end of the sixth month of the first
Lease Year. In the event Tenant wishes to repay the Allowance in full at any
time after the end of the sixth month of the first Lease Year, Tenant may do so
provided that (i) as Landlord may, upon receipt of such funds, apply them to the
mortgage debt encumbering the Land and Building, the Mortgagee holding the
Superior Mortgage (as such terms are defined in Article 20) will accept a
prepayment and (ii) Tenant pays to Landlord, at the time of such repayment, the
amount of any fee or penalty imposed or assessed by the Mortgagee in connection
with such prepayment.

                                 ARTICLE 4 RENT

      4.1 Tenant shall pay to Landlord, without notice or demand, in lawful
money of the United States of America, at the office of Landlord or at such
other place as Landlord may designate, the following:

            (a) annual fixed rent ("Fixed Rent") at the rates and in the amounts
set forth on Exhibit B, together with the amortized Allowance amount (as set
forth in Section 3 above), as additional Fixed Rent. Annual Fixed Rent shall be
payable in equal monthly installments (in amounts as set forth on Exhibit B) in
advance on the first day of each and every calendar month commencing on the date
set forth on Exhibit B and continuing throughout the remainder of the Term.

            (b) additional rent ("Additional Rent") consisting of all other sums
of money as shall become due and payable by Tenant hereunder.

            (c) If Tenant shall fail to pay within ten (10) days of the date
when due any installment of Fixed Rent or any Additional Rent, Tenant shall pay
interest thereon at the annual rate of interest (the "Default Rate") equal to
the lesser of (i) four percentage points per annum above the so-called prime
rate as published in the Money Rates section of The Wall Street Journal (the
"Journal") (or if the Journal ceases to be published or to publish such rates,
then any successor reasonably designated by Landlord), or (ii) the then
prevailing maximum legal rate chargeable to Tenant, from the date when such
installation or payment shall have become due to the date of the payment
thereof, and such interest shall be deemed Additional Rent.

                                       4
<PAGE>

            (d) There shall be no abatement of, deduction from, counterclaim or
setoff against Fixed Rent or Additional Rent except as otherwise specifically
provided in this Lease.

            (e) If the Commencement Date is other than the first day of a month,
Fixed Rent for the first partial month of the Term shall be apportioned in that
percentage which the number of days from the Commencement Date to the end of
that month shall bear to the total number of days in the month in which such
Commencement Date occurs.

                                  ARTICLE 5 USE

      5.1 Tenant shall use and occupy the Premises for executive offices and as
a research and development facility to the extent now and hereafter permitted
under applicable laws, ordinances, codes, rules, regulations, order or other
lawful requirements of each Governmental Authority and for no other purpose
without first obtaining Landlord's written consent. Landlord represents that the
Building is in an I-2 (Industrial Zone) in the Town of Cheshire. Attached hereto
as Exhibit G is a list of uses permitted in the I-2 Zone.

      5.2 Tenant shall not use or occupy, suffer or permit the Premises or any
part thereof to be used in any manner, or anything to be done therein, or suffer
or permit anything to be brought into or kept therein, which would in any way,
(a) cause, or be likely to cause, physical damage to the Building or any part
thereof, (b) constitute a public or private nuisance, (c) discharge
objectionable fumes, vapors or odors in a manner as may unreasonably offend
other occupants, (d) cause substantial or objectionable noise, (e) impair or
interfere with any of the Building's services, including the furnishing of
electrical energy, or the proper and economic cleaning, air conditioning or
other servicing of the Building or the Premises or impair or interfere with the
use of any of the other areas of the Building, or occasion discomfort, annoyance
or inconvenience to Landlord or any of the other tenants or occupants of the
Building other than for such brief interruptions of services as may be
reasonably necessary for Tenant to perform Tenant's Initial Alterations and
permitted future Alterations and after Landlord shall have approved of the work
being performed and Tenant shall have coordinated the conduct of such work with
Landlord. Arch and other tenants at the Building or (f) cause Tenant to default
in any of its other obligations under this Lease.

      5.3 If any governmental license or permit shall be required for the proper
and lawful conduct of Tenant's business in the Premises or any part thereof,
then Tenant, at its expense, shall duly procure and thereafter maintain such
license or permit and submit the same to inspection by Landlord. Tenant shall at
all times comply with the terms and conditions of each such license or permit,
but in no event shall failure to procure and maintain same by Tenant affect
Tenant's obligations hereunder.

      5.4 Tenant shall not place a load upon any floor of the Premises that
exceeds the floor load per square foot that such floor was designed to carry and
which is allowed by certificate, rule, regulation, permit or law.

                           ARTICLE 6 ADDITIONAL RENTAL

      6.1 This Lease is intended by the parties hereto to be a so-called net
lease and the Fixed Rent shall be received by Landlord net of all costs and
expenses related to the Land, the Building and the premises, except as otherwise
set forth herein. Tenant shall pay to Landlord, in addition to Tenant's
obligations with respect to the payment of Tenant's Pro Rata Percentage of Real
Estate Taxes (as defined

                                       5
<PAGE>

below) and Operating Expenses (as defined below), Tenant shall pay all other
costs which are specifically set forth herein, to Landlord, upon demand as
Additional Rent, in the same manner as Fixed Rent, together with reasonable
attorney's fees incurred by the Landlord in connection with any amendments to,
consents under and subleases and assignments of this Lease requested by Tenant
and in connection with the enforcement of rights and pursuit of the remedies of
the Landlord under this Lease (whether during or after the expiration or
termination of the term of this Lease).

      As set forth above and commencing on the first day of the 4th month of the
Term, Tenant shall pay to Landlord, its Tenant's Pro Rata Percentage of the
aggregate of Operating Expenses (as hereinafter defined) and Real Estate Taxes
(as hereinafter defined) incurred by Landlord for or during each Lease Year
during the term of this Lease. Tenant's Pro Rata Percentage is set forth on
Exhibit B, provided that Tenant's Pro Rata Percentage may not be adjusted unless
(i) Landlord or another tenant constructs an addition to the Building or (ii)
Tenant consents in writing to an adjustment being made for any other reason
(which consent will not be unreasonably delayed, conditioned or withheld).

      "Operating Expenses" shall mean all reasonable expenses paid or incurred
by Landlord or on Landlord's behalf in respect of the proper management, repair,
operation and maintenance of the Building, including but not limited to (1)
properly allocated salaries, wages and benefits of employees of Landlord engaged
in the management, repair, operation and maintenance of the Building; (2)
payroll taxes, workmen's compensation, uniforms and related expenses for such
employees; (3) the cost of all charges for oil, gas, steam, oxygen, compressed
air, electricity, any alternate source of energy, heating, ventilation,
air-conditioning, water, sewers and other utilities furnished to the Building
(including the Common areas and leased areas thereof), together with any taxes
on such utilities; (4) the cost of painting non-tenant space; (5) the cost of
all charges for insurance carried by Landlord (with regard to the Land and the
Building and operations therein) including without limitation rent, casualty,
environmental, comprehensive general liability and fidelity insurance with
regard to the Building and the maintenance or operation thereof; (6) the cost of
all supplies (including cleaning supplies), materials and equipment, the rental
thereof and sales and other taxes thereon; (7) depreciation of hand tools and
other movable equipment regularly used in the repair, operation or maintenance
of the Building; (8) the cost of all charges for window and other cleaning and
janitorial services for the common areas only, snow and ice removal, and any
security services to patrol or monitor the common areas; (9) charges of
independent contractors, including, without limitation, the cost of a security
firm, in each case provided such are unaffiliated with Landlord (or if
affiliated provided such charges are competitive) and all such charges are
properly allocated to the Building; (10) repairs and replacements made by
Landlord at its expense (provided that if such cost would, under real estate
accounting principles, be required to be capitalized, then such costs shall be
reasonably amortized over the useful life, as determined in accordance with real
estate accounting principles, together with interest at 11% per annum (unless
the repairs are required by reason of Landlord's gross negligence or willful
misconduct); (11) exterior and interior landscaping; (12) alterations and
improvements to the Building made by reason of and to the extent required to
meet the minimum requirements of applicable law or regulation of any
Governmental Authority or the requirements of insurance bodies; (13) reasonable
management fees which shall not exceed the lesser of (i) those customarily
charged by third party managers for bio-tech buildings in New Haven County or,
(ii) 5% of the amount of gross rents payable under leases (including this Lease)
in place at the Building, provided that if no managing agent is employed by
Landlord, a sum in lieu thereof which is not in excess of the lesser of (y) the
then prevailing rates for management fees payable to third party managers of
other similar buildings located in New Haven County or (z) 5% of the amount of
gross rents payable under leases (including this Lease) in place at the
Building; (14) the cost of any capital improvements or additions to the Building
and of any machinery or equipment installed in the Building which improve the

                                       6
<PAGE>

safety, comfort or amenities available to tenants of the Building or which have
the effect of reducing the expenses which otherwise would be included in
Operating Expenses provided that such costs shall be reasonably amortized over
the useful life, as determined in accordance with real estate accounting
principles, together with interest at 11% per annum; (15) reasonable legal,
accounting and other professional fees incurred in connection with the
operation, maintenance and management of the Building; (16) all other charges
properly allocable to the repair, operation and maintenance of the Building in
accordance with generally accepted accounting principles. Landlord may, in the
event the Premises are less than 95% leased, adjust expenses for only the
following categories or items: snow plowing and landscaping. Landlord will pass
through the actual Operating Expenses and shall not markup or add-on to
Operating Expenses.

      Excluded from Operating Expenses shall be the following: (aa) depreciation
(except as provided above); (bb) interest on and amortization of debts; (cc)
leasehold improvements including redecorating made for tenants of the Building;
(dd) brokerage commissions and advertising expenses for procuring new tenants of
the Building; (ee) refinancing costs (including legal, accounting and other
professional costs in connection thereof); (ff) Real Estate Taxes; (gg) the cost
of any item included in Operating Expenses under clauses (1) - (16) to the
extent that such cost (y) is reimbursed by an insurance company or a condemnor
or a tenant (except as a reimbursement of Operating Expenses) or any other party
or (z) was reimbursable by an insurance company, condemnor, tenant (except as a
reimbursement of Operating Expenses) or other party but not reimbursed by reason
of Landlord's default; (hh) salaries of employees above the grade of building
manager or building superintendent; (ii) legal, accounting and professional fees
incurred by Landlord in negotiating or enforcing any lease of any other tenant
in the Building; and (jj) the cost of repairs made to the Building if the need
for such repair is due to the gross negligence or willful misconduct of
Landlord; and (kk) the cost of performance of Landlord's Work.

      Landlord agrees that prior to incurring any capital expenditure (which
would be of such a nature that it would be included in Operating Expenses) in
excess of $25,000.00, it will give notice to Tenant of the anticipated
expenditure. Tenant shall have 10 days within which to respond to such notice
and Tenant's failure to respond within such 10 day period shall be deemed to
constitute approval of the expenditure. If Tenant, within such 10 day period,
notifies Landlord that it objects to such expenditure, it shall specify the
reason(s) for such objection. Landlord and Tenant shall, in good faith, attempt
to resolve any such objection. If Tenant's objection is based, in whole or in
part, on the cost of the anticipated expenditure, Tenant may put the matter out
for bid to reputable contractors or suppliers and present such bids to Landlord
in connection with their attempts to resolve the objection. If the cost of the
anticipated expenditure is less than $50,000, and despite such good faith
efforts, Landlord and Tenant fail to reach agreement, Landlord, in its sole, but
reasonable, discretion, may elect to incur such expense and it shall, as
appropriate, be included in Operating Expenses. If the cost of the anticipated
expenditure is equal to or greater than $50,000, and despite such good faith
efforts, Landlord and Tenant fail to reach agreement, Landlord shall not incur
the expense.

      "Real Estate Taxes" shall mean and include: (i) all general and special
taxes, assessments, duties and levies, if any, of any kind which are assessed,
levied, charged, confirmed or imposed by any public authority upon the Building,
its operations or the rent provided for hereunder, which are payable (adjusted
after protest or litigation, if any) for any part of the term of this Lease,
including without limitation personal property taxes paid by Landlord with
respect to equipment used in connection with the operation of the Building,
exclusive of penalties or discounts; and (ii) the reasonable expenses of
contesting the amount or validity of any such taxes, charges or assessments,
such expense to be applicable to the period if the term is contested. Excluded
from Real Estate Taxes shall be any capital

                                       7
<PAGE>

levy, net income, estate, succession, inheritance, transfer sales and use, and
franchise taxes payable by Landlord.

      Landlord shall estimate the amount of Operating Expenses and Real Estate
Taxes which may be payable hereunder. Said estimates shall be based upon careful
and reasonable examination of all available economic data and projections. The
amounts of said estimates shall be divided into equal monthly payments which
shall be paid by Tenant in advance, along with Tenant's regular monthly payment
of Fixed Rent. Should the actual amount of Operating Expenses and Real Estates
Taxes provided for above be more or less than Landlord's estimate, then Tenant's
monthly payment as aforesaid shall be adjusted to more nearly reflect the same.

      Within thirty (30) days from the date Landlord presents each annual bill
to Tenant for payments of Operating Expenses and Real Estate Taxes, Tenant will
pay to Landlord in a lump sum that amount by which Tenant's actual pro rata
share exceeds the amount of Tenant's estimated payments theretofore. Should the
amount of Tenant's estimated payments exceed Tenant's Pro Rata Percentage, then
Landlord shall, at Landlord's option, either credit the amount of the
overpayment to the payment of Additional Rent next coming due or within said
thirty (30) day period refund such overpayment to Tenant. A certified bill (from
the Building Manager) for Operating Expenses and a real estate tax bill (or copy
thereof) submitted by Landlord to Tenant shall be sufficient evidence of the
amount of Operating Expenses and Real Estate Taxes with respect to the Land and
improvements thereon. Tenant's Pro Rata Percentage of any Operating Expenses and
Real Estate Taxes in such payments hereunder shall be adjusted in the first and
last years of the Lease to take into consideration the fact that Tenant may only
be in possession for a partial year.

      Tenant may, within 120 days after receiving Landlord's statement of
Operating Expenses, give Landlord written notice ("Review Notice") that Tenant
intends to review Landlord's records of the Operating Expenses for that Lease
Year. Within a reasonable time after receipt of the Review Notice (which period
shall not exceed 60 days), Landlord shall make all pertinent records available
for inspection that are reasonably necessary for Tenant to conduct its review.
Tenant may inspect the records at the office of Landlord or Landlord's property
manager. If Tenant retains an agent to review Landlord's records, the agent must
be with a licensed CPA firm. Tenant shall be solely responsible for all costs,
expenses and fees incurred for the audit. Within 60 days after the records are
made available to Tenant, Tenant shall have the right to give Landlord written
notice (an "Objection Notice") stating in reasonable detail any objection to
Landlord's statement of Operating Expenses for that Lease Year. If Tenant fails
to give Landlord an Objection Notice within the 60 day period or fails to
provide Landlord with a Review Notice within the 120 day period described above,
Tenant shall be deemed to have approved Landlord's statement of Operating
Expenses and shall barred from raising any claims regarding the Operating
Expenses for that Lease Year. If Tenant provides Landlord with a timely
Objection Notice, Landlord and Tenant shall work together in good faith to
resolve any issues raised in Tenant's Objection Notice. If Landlord and Tenant
determine that Operating Expenses for the Lease Year are less than reported,
Landlord shall provide Tenant at Landlord's option either a refund of the amount
of overpayment or with a credit against the next installment of Additional Rent
in the amount of any overpayment by Tenant. Likewise, if Landlord and Tenant
determine that Operating Expenses for the Lease Year are greater than reported,
Tenant shall pay Landlord the amount of any underpayment within 30 days. The
records obtained by Tenant shall be treated as confidential. In no event shall
Tenant be permitted to examine Landlord's records or to dispute any statement of
Operating Expenses unless Tenant has paid and continues to pay all Fixed Annual
Rent and Additional Rent when due.

                                       8
<PAGE>

      Tenant shall pay for all ad valorem taxes on Tenant's Property and its
personal property, if any, and on the value of leasehold improvements relating
to the Premises, to the extent that same are (i) separately assessed and taxed
and (ii) exceed standard building allowances.

      If Landlord shall receive a refund of Real Estate Taxes for any period
during the term of this Lease after the year during which the term of this Lease
shall commence, then Landlord shall pay over to Tenant the pro rata percentage
of Real Estate Taxes paid by Tenant as set forth above, to the extent Tenant
shall have borne any portion of such taxes so refunded, after deducting from any
such taxes so refunded the fees and expenses incurred by Landlord in obtaining
such refund.

      So long as Tenant is not in default of its obligations under this Lease
and Tenant continues to pay its Pro Rata Percentage of Landlord's estimate of
Real Estate Taxes pending a final determination of the amount of Real Estate
Taxes, and if Landlord is not contesting or reviewing the Real Estate Taxes,
Tenant or its designees shall have the right to contest or review all such Real
Estate Taxes by appropriate legal proceedings, (which, if instituted, Tenant or
its designees shall conduct properly and promptly at its own cost and expense,
and free of any expense to Landlord, and, if necessary, Landlord will cooperate
with Tenant and shall execute all documents necessary to accomplish the
foregoing).

      6.2 Any Additional Rent payable pursuant to Article 6 shall be collectable
by Landlord in the same manner as Fixed Rent and Landlord shall have the same
remedies for nonpayment thereof as Landlord has hereunder for non-payment of
Fixed Rent.

                               ARTICLE 7 INSURANCE

      7.1 Tenant, at Tenant's expense, shall comply with all rules, regulations
or requirements of the Connecticut Board of Fire Underwriters and the
Connecticut Fire Insurance Rating Organization or any similar body applicable to
the Premises. Tenant, at Tenant's expense, shall further comply with any and all
safety recommendations of Landlord's or Tenant's insurance companies. Landlord
shall comply with all rules, regulations or requirements of the Connecticut
Board of Fire Underwriters and the Connecticut Fire Insurance Rating
Organization or any similar body applicable to the common areas of the Bui]ding.
Landlord shall further comply with any and all safety recommendation or
Landlord's insurance companies with respect to the common areas of the Building.
Landlord's costs and expenses in connection with the foregoing shall be deemed
to be part of Operating Expenses payable under the provisions of this Lease.

      7.2 If by any reason of any act or omission of the part of Tenant, the
rate of fire insurance with extended coverage on the Building or equipment or
other property of Landlord located at the Building or on the Land or any other
tenant or occupant of the Building shall be higher than it otherwise would be,
Tenant shall reimburse Landlord, on demand, for that part of the premiums for
fire insurance and extended coverage paid by Landlord and such other tenants or
occupants because of such act or omission on the part of the Tenant. Landlord
will include a provision in the leases of other tenants in the Building
substantially similar to the provisions of this Section 7.2.

      7.3 (a) Tenant shall obtain and keep in full force and effect during the
Term, at its own cost and expense and in the following amounts or such greater
amounts as Landlord or the holder of the Superior Mortgages may reasonably
request for the benefit of and protecting Landlord, its property managers and
the holder of the Superior Mortgages (i) ISO Simplified Commercial General
Liability

                                       9
<PAGE>

insurance (with contractual liability rider) against claims for bodily death or
property damage occurring to, upon or about the Premises. The limits of
liability of such insurance shall be an amount of not less than Two Million and
00/100 Dollars ($2,000,000.00) per occurrence, Bodily Injury including death and
Two Million and 00/100 Dollars ($2,000,000.00) per occurrence, Property Damage
Liability or Two Million and 00/100 Dollars ($2,000,000.00) combined single
limit for Bodily Injury and Property Damage Liability; and (ii) insurance
against loss or damage by fire, and such other risks and hazards as are
insurable under present and future standard forms of fire and extended coverage
insurance policies, to Tenant's Property for the full insurable value thereof,
protecting Landlord, the holder of the Superior Mortgages, and Tenant as
insureds as their respective interests may appear.

            (b) Tenant shall obtain such other insurance in such amounts as may
from time to time be reasonably required by Landlord against other insurable
hazards which at the time are commonly and generally insured against by tenants
having similar uses to Tenant's use, with due regard being given to the type of
building, its location, construction, use and occupancy.

            (c) Said insurance is to be written in form and substance
satisfactory to Landlord by a good and solvent insurance company of recognized
standing, admitted to do business in the State of Connecticut, which shall be
reasonably satisfactory to Landlord and Superior Mortgagee. Tenant shall
procure, maintain and place such insurance and pay all premiums and charges
therefor and upon failure to do so Landlord may, but shall not be obligated to,
procure, maintain and place such insurance or make such payments, and in such
event Tenant agrees to pay the amount thereof, plus interest at the Default
Rate, to Landlord on demand and said sums shall be in each instance collectable
as Additional Rent on the first day of the month following the date of payment
by Landlord. Tenant shall cause to be included in all such insurance policies a
provision to the effect that the same will be non-cancelable or non-renewable
except upon thirty (30) days' prior written notice to Landlord. On the earlier
to occur of the date Tenant enters onto the Premises or the Commencement Date,
the original or certified duplicate insurance policies or appropriate
certificates shall be deposited with Landlord. An renewals, replacements, or
endorsements thereto shall also be deposited with Landlord prior to the
expiration of the policies to make certain that said insurance shall be in full
force and effect during the Term.

      7.4 The Landlord shall maintain (the cost of which shall be an Operating
Expense):

            (a) ISO Simplified Commercial General Liability Insurance. The
limits of liability of such insurance shall be an amount not less than Two
Million and 00/100 Dollars ($2,000,000.00) per occurrence, Bodily Injury
including death and Two Million and 00/100 Dollars ($2,000,000.00) per
occurrence, Property Damage Liability or Two Million and 00/100 Dollars
($2,000,000.00) combined single limit for Bodily Injury and Property Damage
Liability. Such policies shall name Tenant as additional insured with respect to
acts caused by or resulting from the negligence of the Landlord at the Building
and include Contractual Liability coverage;

            (b) Property insurance on the Building, the Premises and the Common
Areas insuring the full replacement value thereof, on a Special Causes of
Loss-Replacement Cost basis and shall include, but not be limited to, fire and
extended coverage perils. The property to be insured by the Landlord shall also
include all improvements made by Landlord to the Premises, but shall not include
improvements made by Tenant (unless the Tenant shall (x) give the Landlord
notice of the improvement(s) made by the Tenant together with evidence of the
cost thereof; (y) provide the Landlord and its insurer with the ability to
inspect the same; and (z) pay to the Landlord any increase in the insurance
premiums that may

                                       10
<PAGE>

result by reason of the Tenant having made such improvement(s) nor Tenant's
furniture and furnishings or any fixtures or equipment removable by the Tenant
under the provisions of this Lease; and

            (c) If applicable, Boiler and Machinery coverage in an amount that
is adequate for the exposure at risk.

      7.5 Each party agrees to use its best efforts to include in each of its
fire and extended coverage insurance policies (insuring the Building and
Landlord's property therein, in the case of Landlord, and insuring Tenant's
Property and business interest in the Premises, in the case of Tenant, against
loss, damage or destruction by fire or other casualty) a waiver of the insurer's
right of subrogation against the other party, provided such waiver shall be
obtainable without additional charge, unless the other party shall agree in
writing to pay the insurer's additional charge therefor. The policy of insurance
or certificate thereof delivered to Landlord shall include reference to the
waiver of subrogation referred to above.

                         ARTICLE 8 COMPLIANCE WITH LAWS

      8.1 The Tenant agrees that its obligations to make payment of the Basic
Rent, Additional Rent and all other charges on its part to be paid, and to
perform all of the covenants and agreements on its part to be performed during
the Term hereunder shall not, except as herein set forth in the event of
condemnation by public authority, be affected by any present or future law,
by-law, ordinance, code, rule, regulation, order or other lawful requirement
regulating or affecting the use which may be made of the Premises.

      8.2 Landlord shall comply with all present and future laws, ordinances,
requirements, orders, directives, rules and regulations of federal state, county
and city governments and of all other governmental authorities having or
claiming jurisdiction over the Land (excluding those relating to Tenant's
specific manner of use of the Premises) or appurtenances or any part thereof as
enforced by the applicable governmental authority. Without limiting the
generality of the foregoing, Landlord shall, in performing Landlord's Work,
comply with Americans with Disabilities Act Accessibility Guidelines for
Buildings and Facilities (the "ADAAG"). Except for the Landlord's Work to be
performed under Article 3 of this Lease, the expenses incurred by Landlord under
this Paragraph shall be deemed Operating Expenses under Paragraph 6 of the
Lease.

      8.3 During the Term the Tenant shall comply, at its own cost and expense,
with all applicable laws, by-laws, ordinances, codes, rules, regulations,
orders, and other lawful requirements (including, without limitation, the ADAAG)
of the governmental bodies having jurisdiction, which are applicable to, or by
reason of, the Tenant's particular manner of use of the Premises or the fixtures
and equipment therein and thereon; the orders, rules and regulations of the
National Board of Fire Underwriters, or any other body hereafter constituted
exercising similar functions, which may be applicable to the Premises, the
fixtures and equipment therein or thereon or the use thereof, and the
requirements of all policies of public liability, fire and all other types of
insurance at any time in force with respect to the Premises, the Building or the
Land and the fixtures and equipment therein and thereon (provided the Tenant has
been given notice of the requirements of such policies).

      8.4 In connection with the operation by Arch of its business, Arch has
advised Landlord that it is necessary that Arch conduct at least two emergency
evacuation drills in each calendar year. In connection with the operation by
Tenant of its business, Tenant has also advised Landlord that it is

                                       11
<PAGE>

necessary that Tenant conduct emergency evacuation drills. Landlord has agreed
with Arch and agrees with Tenant to coordinate and cooperate with Arch and
Tenant in the conduct of such drills, and to use reasonable efforts to cause
Arch, Tenant and any other tenants in the Building to conduct drills in
conjunction and cooperatively with each other. Tenant agrees that it shall
cooperate with Landlord and Arch in connection with the conduct of such drills.

      8.5 Tenant or its designees shall have the right, in good faith, to
contest or review the applicability or scope of the application of applicable
laws as they affect the Building (unless Landlord is contesting or reviewing the
same) or the Tenant's operations therein by appropriate legal proceedings,
(which, if instituted, Tenant or its designees shall conduct properly and
promptly at its own cost and expense, and free of any expense to Landlord, and,
if necessary, Landlord will cooperate with Tenant and shall execute all
documents necessary to accomplish the foregoing). Notwithstanding the foregoing,
Tenant shall promptly comply with any and all directives, orders, rulings, laws,
rules and regulations if at any time the Building or any part thereof shall then
be immediately subject to forfeiture, or if Landlord or Tenant shall be subject
to any civil criminal liability or penalty arising out of any non-compliance or
claimed non-compliance, or if failure to comply may result in a lien being
placed against the Premises, or if the holder of any Superior Mortgage shall
require compliance.

                       ARTICLE 9 ALTERATIONS; IMPROVEMENTS

      9.1 Tenant shall make no changes or alterations in or to the Premises of
any nature without Landlord's prior written consent, which consent shall not be
unreasonably withheld, delayed or conditioned (provided that Tenant may make
interior, non-structural alterations which do not affect the building systems
(including the heating, ventilating and air conditioning systems, plumbing,
electrical and mechanical systems) or the roof and which cost less than
$100,000.00 without the Landlord's consent), provided that (i) Tenant delivers
plans and specifications to Landlord for such alterations; (ii) Tenant otherwise
complies with the provisions of Section 9.2 below); (iii) Landlord's engineer
and/or architect reviews and approves all plans and specifications for and
inspects the construction of changes or alterations that affect the Building
systems (including the heating, ventilating and air conditioning systems,
plumbing, electrical and mechanical systems) or the roof; and (iv) the same are
conducted in accordance with the terms of Superior Mortgages. All fixtures,
partitions and items of personal property which are permanently affixed to the
Premises or the Building systems, railings and like installations, installed in
the Premises at any time, either by Tenant or by Landlord shall remain upon and
be surrendered with the Premises unless Landlord, by notice to Tenant given no
later than 60 days prior to the Expiration Date or upon the prior termination of
this Lease, elects to have them removed by Tenant, in which event, the same
shall be removed from the Premises by Tenant, at Tenant's expense. Landlord
agrees that Tenant may remove the Tenant's Property, including items described
on Exhibit J (and enhancements to and replacements of such items as shall be
identified by Tenant to Landlord) upon the expiration or termination of the
Lease and Tenant agrees that it shall remove the same if Landlord requests that
do so within 60 days prior to the Expiration Date. Nothing in this Section shall
be construed to prevent Tenant's removal of Tenant's Property, but upon removal
of any Tenant's Property from the Premises or upon removal of other
installations as may be required or permitted by Landlord, Tenant shall
immediately, and at its expense, repair and restore the Premises to the
condition existing prior to installation and repair any damage to the Premises
or the Building due to such removal. All property permitted or required by
Landlord to be removed from the Premises at the end of the Term remaining in the
Premises after Tenant's removal shall be deemed abandoned and may, at the
election of Landlord, either be retained as Landlord's property or may be
removed from the Premises by Landlord at Tenant's expense.

                                       12
<PAGE>

      9.2 Tenant shall, before making any alterations, additions, installations
or improvements, at its expense, obtain all permits, approvals and certificates
required by any governmental or quasi-governmental bodies and (upon completion)
certificates of final approval thereof and shall deliver promptly duplicates of
all such permits approvals and certificates to Landlord and Tenant agrees to
carry and will cause Tenant's contractors and subcontractors to carry such
workmen's compensation, general liability, personal and property damage
insurance as Landlord may reasonably require. Notwithstanding anything in this
Lease to the contrary Tenant shall, unless Landlord in the exercise of its sole
discretion otherwise permits Tenant to use its contractors, use Landlord's
contractors in connection with any work involving tie-ins to building systems or
roof penetrations. As permitted by law, Tenant agrees to obtain and deliver to
Landlord written and unconditional waivers or subordinations of mechanic's liens
upon the Land and Building for all work, labor and services to be performed and
all materials to be furnished in connection with such work and certificates of
full payment, signed by all contractors, sub-contractors materialmen and
laborers to become involved in such work. Notwithstanding the foregoing, if any
mechanic's lien is filed against the Premises, Land or Building for work claimed
to have been done for, or materials furnished to, Tenant, whether or not done
pursuant to this Article, the same shall be discharged by Tenant within thirty
(30) days thereafter, at Tenant's expense, by filing the bond required by law or
by paying the claim.

                               ARTICLE 10 REPAIRS

      10.1 Tenant shall take care of the Premises and, at Tenant's sole cost and
expense, shall (i) make all repairs and replacements, as and when needed to
preserve the Premises in good working order and condition, except that Tenant
shall not be required to make any structural repairs or structural replacements
to the Premises unless necessitated or occasioned by the acts, omissions or
negligence of Tenant, or any of its servants, employees, contractors, agents,
visitors, invitees, or licensees, or by the use or occupancy or manner of use or
occupancy of the Premises by Tenant or any such person; and (ii) provide for
customary rubbish removal service for the Premises and keep and maintain the
Premises, clean and free of debris.

      10.2 Landlord shall keep and maintain the Building and its fixtures,
appurtenances, systems and facilities serving the premises in good working
order, condition and repair and shall make all repairs, structural and
otherwise, interior and exterior, as and when needed in or about the Building,
the costs of which shall be included in the Operating Expenses, except for (i)
those repairs for which Tenant is responsible pursuant to any other provision,
including but not limited to Section 10.1 above, or (ii) repairs to Tenant's
Property provided, however, that Landlord shall have no obligation or liability
for repairs in the Premises until receipt of written notice from Tenant
specifying the repairs required.

      10.3 Tenant shall, at all times, designate a contact person(s) having
availability 24 hours a day, 7 days a week, to (i) provide Landlord with access
to the Premises in the event of an emergency; and (ii) respond to alarms.

                        ARTICLE 11 UTILITIES AND SERVICES

      11.1 Landlord shall furnish and distribute to the Premises through the
base Building system pre-conditioned outside air, at a temperature range of
between 53(degree) F and 58(degree) F (with a set point of 55(degree) F) in
reasonable volumes and velocities on a year round basis on Business Days from
6:00 A.M. to 6:00 P.M. Monday through Friday and Saturdays 6:00 A.M. to 12:00
noon. Landlord covenants that it will, as required, run both chillers in an
effort to maintain the temperature at or approximate to the 55(degree) F set

                                       13
<PAGE>

point. The term "Business Days" shall mean all days except Sundays and days
observed by the federal government as legal holidays. If Tenant shall require
such service at any other time ("after hours"). Landlord shall furnish after
hours service upon reasonable advance notice from Tenant, given between the
hours of 9:00 AM. and 1:00 P.M. of any week-day, Business Day, and Tenant shall
pay the actual charges therefor on Landlord's demand. If any of the other
tenants of the Building shall request and receive after hours service, pursuant
to Landlord's obligation to provide the same to them, at the same time as
Tenant, only that equitably prorated portion of the charge made by Landlord by
such service shall be allocated to Tenant. Tenant shall be responsible for and
pay costs associated with (i) the installation, maintenance, repair and
operation of any equipment necessary to provide humidification to the Premises;
and (ii) the installation of any additional equipment together with the
maintenance, repair and operation of all such additional equipment necessary to
re-heat the air. All of Tenant's work in connection with the installation of
such equipment shall be performed in accordance with the provisions of Article 9
hereof.

      11.2 (a) From and after the earlier to occur of (i) the date Tenant's
business is fully operational in the Premises (i.e. when Tenant's equipment has
been installed and personnel moved in) or (ii) the first day of the 7th month of
the Term (such date, the "Utility Commencement Date"), Tenant shall pay for all
electricity, gas, water and all other utilities used or consumed at the
premises, as Additional Rent.

            (b) Tenant shall pay to Landlord a Premises Electric Charge of,
initially, $5.00 per square foot per annum. The Premises Electric Charge shall
be payable in equal monthly installments, in advance, together with Tenant's
monthly payment of Fixed Rent. Landlord shall, at Landlord's expense, prior to
the end of the Arch Move-Out Period, install a submeter to measure Tenant's
consumption of electricity at the Premises. The cost of electricity shall be
determined on the basis of the rate charged for such load and usage in the
service classification in effect from time to time pursuant to which Landlord
then purchased electric current for the entire Building. The Premises Electrical
Charge shall be reconciled with the actual costs approximately every 6 months
during the first 12 month period following the Utility Commencement Date and not
less than annually thereafter. The Premises Electrical Charge shall be adjusted,
if necessary, from time to time, to appropriately reflect the cost of
electricity delivered to and consumed at the Premises.

            (c) Tenant's use of electrical service shall not exceed, either in
voltage, rated capacity, or overall load, that which Landlord deems to be
standard for the Building. The electric capacity of the Building expressed in
watts per square foot ("w/sf") is 40 w/sf for the entire Building, including
mechanical systems, and 20 w/sf for non-mechanical loads. Tenant shall be
permitted to utilize its pro rata share of such electrical service. If Tenant
requests permission to consume excess electrical service, Landlord may condition
consent upon conditions that Landlord reasonably elects (including, without
limitation, the installation of utility service upgrades, additional submeters,
air handlers or cooling units), and the additional usage, installation and
maintenance costs shall be paid by Tenant. Electrical service to the Premises
may be furnished by one or more companies providing electrical generation,
transmission and distribution services, and the cost of electricity may consist
of several different components or separate charges for such services, such as
generation, distribution and stranded cost charges. Landlord shall have the
exclusive right to select any company providing electrical service to the
Premises, to aggregate the electrical service for the Land and Premises with
other building, to purchase electricity through a broker and/or buyers group and
to change the providers and manner of purchasing electricity.

            (d) If either the quantity or character of utility service is
changed by the public utility corporation supplying such service to the Building
or the Premises is no longer available or suitable for

                                       14
<PAGE>

Tenant's requirements, no such change, unavailability or unsuitability shall
constitute an actual or constructive eviction, in whole or in part, or entitle
Tenant to any abatement or diminution of rent, or relieve Tenant from any of its
obligations under this Lease, or impose any liability upon Landlord or
Landlord's agents.

      11.3 (a) Landlord shall supply water from a 4" street main with a gallon
per minute ("gpm") flow of 250 gpm to a point or points in the Premises. Tenant
shall be permitted to utilize its pro rata share of such water service. Tenant
shall pay for all water consumed or utilized at the Premises. Landlord may, at
Landlord's cost, install a water meter or submeter and thereby measure Tenant's
consumption of water for all purposes. Tenant, at Tenant's sole cost and
expense, shall keep any such meter or submeter and any such installation
equipment in good working order and repair. Tenant shall pay for water consumed
as shown on said meter or submeter and sewer charges thereon, as and when bills
are rendered.

            (b) Tenant agrees that (i) all waste water discharged from the
Premises, including from laboratories, shall be free of all chemicals and
biological waste other than those Tenant is permitted to discharge pursuant to
applicable law and/or valid permits into the Building's collection facility and
into the sanitary sewer system; and (ii) it shall collect all chemicals and
biological waste into appropriate hazardous waste storage receptacles and
discard the same in accordance with applicable laws and shall not dispose of the
same through the Building's plumbing system, unless, and only to the extent,
Tenant is permitted to do so by law and/or valid permits.

      11.4 Landlord reserves the right to stop the service of the air
conditioning, elevator, plumbing, electrical, sanitary mechanical or other
service or utility systems of the Building when necessary by reason of accident
or emergency, or mechanical breakdown, or requirement of law or any cause beyond
Landlord's reasonable control or, after notice to Tenant, for repairs,
alterations, replacements or improvements, which in the judgement of Landlord,
are desirable or necessary. Except in the event of an emergency or systems
failure caused by an accident or other cause beyond Landlord's reasonable
control, Landlord shall use commercially reasonable efforts to give Tenant as
much prior notice as possible prior to the stoppage.

      11.5 The Landlord shall not be required to provide heat, air conditioning,
or ventilation to the Premises if any action of the Tenant, Act of God, or other
unforeseen circumstances makes it impossible for the Landlord reasonably to do
so. Further, Landlord shall not be liable for the interruption, curtailment,
stoppage or suspension of services and utilities when necessary by reason of
accident or emergency or suspension of utility services or when necessary for
repairs, alterations, replacements or improvements desirable or necessary in the
reasonable judgment of Landlord or for any cause beyond the reasonable control
of Landlord. Landlord shall use commercially reasonable efforts to restore
services after an interruption shall occur. In the event of any such
interruption, curtailment, stoppage or suspension, there shall be no diminution
or abatement of rent, additional rent or other charges due from Tenant to
Landlord hereunder, Tenant's obligations hereunder shall not be affected or
reduced, and Landlord shall have no responsibility or liability for any such
interruption, curtailment, stoppage or suspension. Notwithstanding anything to
the contrary contained in this section 11.5, in the event there shall be an
interruption, curtailment or a suspension of a building system ("Service
Interruption") and (i) if such Service Interruption shall continue for more than
5 consecutive Business Days; and (ii) such Service Interruption shall materially
impair the operation of Tenant's business in the Premises, rendering all or any
material part of the Premises inaccessible or untentantable and Tenant's
generator (if any) has not functioned in a manner that would permit Tenant to
continue to operate in all or a material portion of

                                       15
<PAGE>

the Premises and (iii) such Service Interruption has not been caused by the
public utility servicing or supplying the Building or by an act of Tenant or
Tenant's servants, employees or contractors, then as Tenant's sole remedy in
connection with such Service Interruption, Tenant shall be entitled to an
abatement of Fixed Rent and Additional Rent (based on the square footage of the
Premises subject to the Service Interruption) beginning on the sixth consecutive
Business Day of such Service Interruption and ending on the date such Service
Interruption ceases.

      11.6 Landlord shall provide a parking area contiguous or adjacent to the
Building. Tenant shall have the non-exclusive right to use its proportionate
share of the available parking spaces and the right together with the other
tenants and occupants of the Building, and its and their employees, agents, and
invitees, to use any driveways appurtenant thereto for the purposes of egress
and ingress, parking of vehicles for itself, its customers, and employees in
connection with and incidental to the business conducted by Tenant in the
Premises, all without additional charge.

      11.7 Landlord agrees to (a) provide building security to the Building,
which may be through the installation and maintenance of a card access system
(Tenant shall be able to access the Premises 24 hours a day, 7 days a week); (b)
maintain and repair the parking areas, flag poles, driveways, curbs and
sidewalks on the Land, (c) to keep the surface of the parking area, driveways
and sidewalks located on the Land reasonably free from snow, ice, dirt and
rubbish and (d) to insure, protect and maintain the common areas located on the
Land, whether or not sheltered, including the maintenance of shrubbery and grass
areas in and around the Building; (e) maintain a back-up generator to provide
power for emergency services to the Building; and (f) at all times designate a
contact person(s) having availability 24 hours a day 7 days a week to respond to
Tenant in the event of an emergency. Landlord shall use commercially reasonable
efforts, from time to time, as needed, to control the goose population that
inhabits the Common Areas, from time to time. Landlord's expense in performing
such obligations shall be part of the Operating Expenses described in Article 6.
Tenant shall, at Tenants sole election, cost and expense, install, maintain,
repair and operate any back-up generator necessary or desirable for the conduct
of its operations. If the generator would best be located in a common area,
Landlord shall, in accordance with the provisions of Section 2.1 hereof, give
Tenant permission to so locate the same. Tenant may also place and maintain a
flag on one of the flag poles on the Land.

               ARTICLE 12 DAMAGE TO OR DESTRUCTION OF THE PREMISES

      12.1 Except as provided below, in the event of partial or total
destruction of the Premises during the Term by fire or other casualty, the
Landlord shall, as promptly as practicable after receipt of any insurance
proceeds available as a result of such casualty, repair, reconstruct or replace
the portions of the Premises destroyed as nearly as possible to their condition
prior to such destruction, except that in no event shall the Landlord be
obligated to expend more for such repair, reconstruction or replacement than the
amounts of any such insurance proceeds actually received. Commencing on the date
of such casualty and during the period of such repair, reconstruction and
replacement there shall be an equitable abatement of Fixed Rent hereunder for up
to one (1) year from the date of such casualty in proportion to the loss of
usable floor area in the Premises.

      12.2 If (i) the Building is so extensively destroyed by fire or other
casualty that an independent engineer or architect certifies that the Premises
cannot reasonably be expected to be susceptible of repair, reconstruction or
replacement within a period of two hundred-ten (210) days from the Deemed Start
Date (as defined below) and if the damage shall materially and adversely
interfere with the conduct of Tenant's business; or (ii) any damage results from
causes or risks not required to be insured against by

                                       16
<PAGE>

the Landlord hereunder or (iii) any holder of a Superior Mortgage refuses to
promptly make such net proceeds available for such repair, reconstruction or
replacement; or (iv) a casualty occurs during the last 2 years of the Initial
Term or any Extended Term and an independent engineer or architect certifies
that the Premises cannot reasonably be expected to be susceptible to repair,
reconstruction or replacement within 90 days of the Deemed Start Date, the
Landlord or Tenant may terminate this Lease by giving written notice to the
other within sixty (60) days after the date of such destruction. Provided
further, that if, despite diligent efforts, the Landlord has been unable to
restore or, if an independent engineer or architect, after the passage of 180
days from the Deemed Start Date, determines (at Tenant's sole cost and expense),
that Landlord's progress is such that it is not likely that the Landlord will be
able to restore the Premises to their condition prior to such destruction within
two hundred-ten (210) days following the Deemed Start Date, then (y) Tenant may
terminate this Lease by giving Landlord thirty (30) days' prior written notice,
unless Landlord substantially completes the repair and restoration work within
said thirty (30) day period or performs a sufficient amount of work so that it
appears likely that Landlord will complete restoration within 210 days from the
Deemed Start Date, in which event the termination notice shall be null and void;
or (z) Landlord may terminate this Lease by written notice to the Tenant. In the
event of any such notice of termination, this Lease shall terminate as of, and
Fixed Rent and Additional Rent shall be appropriately apportioned through and
abated from and after, the date of such notice of termination. The "Deemed Start
Date" shall mean the earlier to occur of the (i) date work on rebuilding or
restoration actually commences; or (ii) date which is ninety days after the date
of the casualty, provided, however, if arson or another criminal investigation
concerning the origins of the casualty is pending, then the Deemed Start Date
shall mean the date work actually commences.

      12.3 Landlord shall not be liable for any inconvenience or annoyance to
Tenant or injury to the business of Tenant resulting in any way from such damage
by fire or other casualty or the repair thereof. Landlord will not carry
insurance of any kind on Tenant's Property, and Landlord shall not be obligated
to repair any damage thereto or replace the same.

                            ARTICLE 13 EMINENT DOMAIN

      13.1 If more than twenty percent (20%) of the usable floor area of the
Premises, or more than twenty percent (20%) of the parking area available for
use by the Tenant shall be taken by eminent domain or appropriated by public
authority or if the Tenant shall be deprived of suitable vehicular or pedestrian
access to the Premises or the Property by virtue of such a taking or
appropriation, the Landlord or the Tenant may terminate this Lease by giving
written notice to the other within thirty (30) days after such taking or
appropriation. In the event of such a termination, this Lease shall terminate as
of the date the Tenant must surrender possession or, if later, the date the
Tenant actually surrenders possession, and the Fixed Rent and Additional Rent
reserved shall be apportioned and paid to and as of such date.

      13.2 If all or any part of the Premises is taken or appropriated by public
authority as aforesaid and this Lease is not terminated as set forth above, the
Landlord shall, subject to the rights of any holder of any Superior Mortgagee,
as promptly as practicable, apply any such damages and compensation awarded (net
of the costs and expenses, including reasonable attorneys' fees, incurred by the
Landlord in obtaining the same) to secure and close so much of the Premises as
remain and shall restore the Building to an architectural whole and except that
in no event shall the Landlord be obligated to expend more for such replacement
than the net amount of any such damages, compensation or award which the
Landlord may have received as damages in respect of the Building and any other
improvements situated on the Property as they existed immediately prior to such
taking or appropriation; in such event there shall be an

                                       17
<PAGE>

equitable abatement of Fixed Rent in proportion to the loss of usable floor area
in the Premises after giving effect to such restoration, from and after the date
the Tenant must surrender possession or, if later, the date the Tenant actually
surrenders possession.

      13.3 In the event of any such acquisition or condemnation of all or any
part of the Building and/or Land, Landlord shall be entitled to receive the
entire award for any such acquisition or condemnation. Tenant shall have no
claim against Landlord or the condemning authority for the value of any
unexpired portion of the Term and Tenant hereby expressly assigns to Landlord
all of its right, title and interest in any to any such award, and also agrees
to execute any and all further documents that may be required in order to
facilitate the collection thereof by Landlord. Nothing contained in this Section
shall be deemed to prevent Tenant from making a separate claim in any
condemnation proceedings (but not against Landlord) for any moving expenses or
any other expenses, claims or damages to which Tenant may be entitled, provided
the award thereof does not diminish the award otherwise payable to Landlord and
for the value of any Tenant's Property which would be removable at the end of
the Term pursuant to the provisions of Article 9.

                       ARTICLE 14 CONDITIONS OF LIMITATION

      14.1 This Lease and the Term and estate hereby granted are subject to the
limitation that;

            (a) if Tenant shall file a voluntary petition in bankruptcy or
insolvency, or shall be adjudicated a bankrupt or insolvent, or shall file any
petition or answer seeking any reorganization, arrangement, composition,
readjustment, liquidation, dissolution or similar relief under the present or
any future federal bankruptcy act or any other present or future applicable
federal, state or other statute or law, or shall make an assignment for the
benefit of creditors or shall seek or consent to or acquiesce in the appointment
of any trustee, receiver or liquidator of Tenant or of all or any part of
Tenant's Property; or

            (b) if, within sixty (60) days after the commencement of any such
proceeding against Tenant, such proceeding shall not have been dismissed, or if,
within sixty (60) days after the appointment of any trustee, receiver or
liquidator of Tenant, or of all or any part of Tenant's property, without the
consent or acquiescence of Tenant, such appointment shall not have been vacated
or otherwise discharged, or if any execution or attachment shall be issued
against Tenant or any of Tenant's Property pursuant to which the Premises shall
be taken or occupied or attempted to be taken or occupied; or

            (c) if Tenant shall default in the payment when due of any
installment of Fixed Rent or in the payment when due of any Additional Rent
(provided that Landlord shall, not more than 2 times in any 12 consecutive month
period provide Tenant with ten (10) days' written notice and opportunity to cure
Tenant's failure to pay Fixed Rent or Additional Rent when due); or

            (d) if Tenant shall default in the observance or performance of any
term, covenant or condition of this Lease on Tenant's part to be observed or
performed (other than the covenants for the payment of Fixed Rent and Additional
Rent) and Tenant shall fail to remedy such default within thirty (30) days after
notice by Landlord to Tenant of such default, or if such default is of such a
nature that it cannot be completely remedied within said period of thirty (30)
days if Tenant shall not promptly commence to cure the same and thereafter
remedy the default within sixty (60) days after such notice of default; or

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<PAGE>

            (e) if any event shall occur or any contingency shall arise whereby
the estate hereby granted or the unexpired balance of the Term would, by
operation of law or otherwise, devolve upon or pass to any person, firm or
corporation other than Tenant except as is expressly permitted under Article 19;
or

            (f) if the Premises shall become deserted or abandoned for a period
of sixty (60) consecutive days;

then in any of said events Landlord may, to the extent permitted by law,
immediately or at any time thereafter, and without notice or demand, terminate
this Lease.

      14.2 Any monies received by Landlord from or on behalf of Tenant during
the pendency of any proceeding of the types referred to in said Subsections (a)
and (b) of Section 14.1 shall be deemed paid as compensation for the use and
occupation of the premises and the acceptance of any such compensation by
Landlord shall not be deemed an acceptance of rent or a waiver on the part of
Landlord of any rights under Section 14.1.

      14.3 In the event Tenant becomes the subject debtor in a case pending
under the Bankruptcy Code (11 U.S.C. Section 10 et. seq.), Landlord's right to
terminate this Lease shall be subject to the rights of the Trustee in bankruptcy
to assume or assign this Lease. To the extent permitted or allowed by law, the
Trustee shall not have the right to assume or assign this Lease until the
Trustee (a) promptly cures all defaults under this Lease, (b) promptly
compensates Landlord for monetary damages incurred as a result of such default,
and (c) provides "adequate assurance of future performance" which shall mean, in
addition to any other requirements of 11 U.S.C. Section 365(b)(3), that all of
the following have been satisfied: (i) in addition to rent payable under the
Lease, the Trustee shall establish with Landlord a security deposit equal to
three (3) months' Fixed Rent; (ii) maintain said security deposit in said amount
whenever it is drawn upon by Landlord; (iii) Trustee must agree that Tenant's
business shall be conducted in a first-class manner; and (iv) the use of the
Premises cannot change. If all the foregoing are not satisfied, Tenant shall be
deemed not to have provided Landlord with adequate assurance of future
performance of this Lease.

                    ARTICLE 15 RE-ENTRY BY LANDLORD; REMEDIES

      15.1 If this Lease and the Term shall terminate as provided in Article 14;

            (a) To the extent permitted by law, Landlord and Landlord's agents
may immediately, or at any time after such default or after the date upon which
this Lease shall terminate, re-enter the Premises or any part thereof, without
notice, either by summary proceeding or by any other applicable action or
proceeding, and may repossess the Premises and dispossess Tenant and any other
persons from the Premises and remove any and all of its or their property and
effects from the Premises and in no event shall re-entry be deemed an acceptance
of surrender of this Lease; and

            (b) Landlord, at Landlord's option, may relet the whole or any part
or parts of the Premises from time to time, either in the name of Landlord or
otherwise, to such tenant or tenants, for such term or terms ending before, on
or after the Expiration Date, at such rental or rentals and upon such other
conditions, which may include concessions and free rent periods, as Landlord, in
its reasonable discretion, may determine. Landlord shall use commercially
reasonable efforts to mitigate its damages, but Landlord shall in no event be
liable for failure to relet the Premises or any part thereof, or, in the

                                       19
<PAGE>
event of any such reletting, for failure to collect any rent due upon any such
reletting, and no failure shall operate to relieve Tenant of any liability under
this Lease or otherwise to affect any such liability. Landlord at Landlord's
option, may make such repairs, replacements, alterations, additions,
improvements, decorations and other physical changes in and to the Premises as
Landlord, in its sole, but commercially reasonable, discretion, considers
advisable or necessary in connection with any such reletting or proposed lease.
Tenant shall be liable for the amount of all expenses incurred by Landlord in
connection with such repairs, replacements, alterations additions, improvements,
decorations and other physical changes made by Landlord and the costs of such
reletting, including without limitation, brokerage and reasonable legal
expenses.

      15.2 Subject to applicable law, Tenant waives any rights to (a) redeem the
Premises, (b) re-enter or repossess the Premises, or (c) restore the operation
of this Lease, after Tenant shall have been dispossessed by a judgment or by
warrant of any court or judge, or after any re-entry by Landlord, or after any
expiration or termination of this lease and the Term, whether such dispossess,
reentry, expiration or termination shall be by operation of law or pursuant to
the provisions of this Lease. The words "re-enter", "re-entry" and "re-entered"
as used in this Lease shall not be deemed to be restricted to their technical
legal meanings.

      15.3 In the event of any breach (and, as to such threatened breach, if a
breach occurred there would be a reasonable likelihood of imminent danger to
person or property) or threatened breach by Tenant or any persons claiming
through or under Tenant of any of the agreements, terms, covenants or conditions
contained in this Lease, Landlord shall be entitled to enjoin such breach or
threatened breach and shall have the right to invoke any right and remedy
allowed at law or in equity or by statute or otherwise as if re-entry, summary
proceedings or other specific remedies were not provided for in this Lease.

      15.4 If this Lease and the Term shall terminate as provided in Article 14,
or by or under any summary proceeding or any other action or proceeding, or if
Landlord shall re-enter the Premises as provided in this Article, or by or under
any summary proceeding or any other action or proceeding then, in any of said
events:

            (a) Tenant shall pay to Landlord all Fixed Rent and Additional Rent
to the date upon which this Lease and the Term shall have terminated or to the
date of re-entry upon the Premises by Landlord, as the case may be;

            (b) Landlord shall be entitled to retain all monies, if any, paid by
Tenant to Landlord, whether as advance rent, security or otherwise, but such
monies shall be credited by Landlord against any Fixed Rent or Additional Rent
due at the time of such termination or re-entry, or at Landlord's option,
against any damages payable by Tenant;

            (c) Tenant shall be liable for and shall pay to Landlord any
deficiency between (i) the Fixed Rent or Additional Rent payable hereunder for
the period which otherwise would have constituted the unexpired portion of the
Term (conclusively presuming the Additional Rent to be the same as was payable
for the year immediately preceding such termination or re-entry) and (ii) the
net amount, if any, of rents ("Net Rent") collected under any reletting effected
pursuant to the provisions of Section 15.1(b) for any part of such period
(first deducting from the rents collected under any such reletting all of
Landlord's expenses in connection with the termination of this Lease or
Landlord's re-entry upon the Premises and in connection with such reletting
including but not limited to all repossession costs,

                                       20
<PAGE>

brokerage commissions, legal expenses, attorneys' fees, alteration costs and
other expenses for preparing the Premises for such reletting);

            (d) Any such deficiency shall be paid in monthly installments by
Tenant on the days specified in this Lease for the payment of installments of
Fixed Rent. Landlord shall be entitled to recover from Tenant each monthly
deficiency as the same shall arise and no suit to collect the amount of the
deficiency for any month shall prejudice Landlord's right to collect the
deficiency for any subsequent month by a similar proceeding. Alternatively, suit
or suits for the recovery of such deficiencies may be brought by Landlord from
time to time at its election;

            (e) Whether or not Landlord shall have collected any monthly
deficiencies as aforesaid, Landlord shall, at its sole option, be entitled to
recover from Tenant, and Tenant shall pay Landlord, on demand, as and for
liquidated and agreed final damages, a sum equal to the amount by which the
Fixed Rent and Additional Rent payable hereunder for the period which otherwise
would have constituted the unexpired portion of the Term (conclusively presuming
the Additional Rent to be the same as was payable for the year immediately
preceding such termination or re-entry) exceeds then fair and reasonable rental
value of the Premises for the same period, both discounted to present worth at
the rate of ten percent (10%) per annum. If, before presentation of proof of
such liquidated damages to any court, commission or tribunal, the premises, or
any part thereof, shall have been relet by Landlord for the period which
otherwise would have constituted the unexpired portion of the Term, or any part
thereof, the amount of rent upon such reletting, shall be deemed, prima facie,
to be the fair and reasonable rental value for the part or the whole of the
Premises so relet during the term of the reletting, provided said reletting is
on commercially reasonable terms. In no event shall Landlord recover double
damages from Tenant by pursuing alternative recoveries.

            (f) In no event (i) shall Tenant be entitled to receive any excess
of such Net Rent over the sums payable by Tenant to Landlord hereunder, or (ii)
shall Tenant be entitled in any suit for the collection of deficiencies or
damages pursuant to this Section to a credit in respect of any Net Rent from a
reletting except to the extent that such Net Rent is actually received by
Landlord prior to the commencement of such suit. If the Premises or any part
thereof should be relet in combination with other space, then proper
apportionment on a square foot area basis shall be made of the rent received
from such reletting and of the expenses of reletting.

      15.5 (a) If this Lease be terminated as provided in Article 14 or by or
under any summary proceeding or any other action or proceeding, or if Landlord
shall re-enter the Premises, Tenant covenants and agrees, notwithstanding
anything to the contrary contained in this Lease;

                  (i) That the Premises shall be, upon such earlier termination
or re-entry, in the same condition as that in which the Tenant has agreed to
surrender them to Landlord at the expiration of the Term hereof;

                  (ii) That Tenant, on or before the occurrence of any event of
default, shall have performed every covenant contained in this Lease for the
making of any improvement, alteration or betterment to the Premises, or for
restoring or rebuilding any part hereof; and

                  (iii) That, for the breach of either Subdivision (i) or (ii)
of this Subsection, or both, Landlord shall be entitled immediately, without
notice or other action by Landlord, to recover, and Tenant shall pay the then
cost of performing such covenant, plus interest thereon at the Default Rate for

                                       21
<PAGE>

the period between the occurrence of any event of default and the time when any
such work or act, the cost of which is computed, should have been performed
under the other provisions of this Lease had such event of default not occurred.

            (b) Each and every covenant contained in this Section shall be
deemed separate and independent, and not dependent on other provisions of this
Lease or the use and occupation of the Premises by Tenant, and the performance
of any such covenant shall not be considered to be rent or other payment for the
use of said Premises. It is understood that the consideration for the covenants
in this Section is the making of this Lease, and the damages for failure to
perform the same shall be deemed to be in addition to and separate and
independent of the damages accruing by reason of default in observing any other
covenant contained in this Lease.

      15.6 Nothing herein contained shall be construed as limiting or precluding
the recording by Landlord against Tenant of any sums or damages to which, in
addition to the damages particularly provided above, Landlord may lawfully be
entitled by reason of any default hereunder on the part of Tenant.

      15.7 Each right and remedy of Landlord provided for in this Lease shall be
cumulative and shall be in addition to every other right and remedy provided for
in this Lease, or now or hereafter existing at law or in equity or by statute or
otherwise, and the exercise or beginning of the exercise by Landlord of any one
or more of the rights or remedies provided for in this Lease, or now or
hereafter existing at law or in equity or by statute or otherwise, shall not
preclude the simultaneous or later exercise by Landlord of any or all other
rights or remedies provided for in this Lease or now or hereafter existing at
law or in equity by statute or otherwise.

              ARTICLE 16 CURING TENANT'S DEFAULT; FEES AND EXPENSES

      16.1 If Tenant shall default in the observance or performance of any term,
covenant, or condition of this Lease on Tenant's part to be observed or
performed, Landlord, without thereby waiving such default, may perform the same
for the account and at the expense of Tenant, without notice in a case of
emergency and in any other case if such default continues after thirty (30) days
from the date of the giving by Landlord to Tenant of notice of intention so to
do or such lesser period of notice in the event that a condition might
constitute a default under a Superior Mortgage. Landlord may enter the Premises
at any time to cure any default. Bills for any expense incurred by Landlord in
connection with any such performance by it for the account of Tenant, and bills
for all costs, expenses and disbursements of every kind and nature whatsoever,
including reasonable counsel fees, involved in collecting or endeavoring to
collect Fixed Rent or Additional Rent or other charge or any part thereof or
enforcing or endeavoring to enforce any rights against Tenant, under or in such
cost, expense and disbursement involved in instituting and prosecuting summary
proceedings, as well as bills for any property, material, labor or services
provided, furnished or rendered by Landlord to Tenant and any charges for
services provided under this Lease, may be sent by Landlord to Tenant monthly or
immediately, and shall be due and payable in accordance with the terms of said
bills and if not paid when due, the amounts thereof shall immediately become due
and payable as Additional Rent. Any such bill shall be payable with interest at
the Default Rate from the date Landlord incurs the charge or expense to the date
of payment by Tenant to Landlord. Tenant's obligations under this Section shall
survive the Expiration Date or sooner termination of the Term.

                  ARTICLE 17 NON-LIABILITY AND INDEMNIFICATION

                                       22
<PAGE>

      17.1 Except as provided in Section 17.3(b) below, neither Landlord nor any
agent or employee of Landlord, shall be liable to Tenant, its employees, agents,
contractors, invitees and licensees, and Tenant shall save Landlord and
Landlord's agents harmless of and from all loss, cost, liability, claim, damage
and expense including reasonable counsel fees, penalties and fines incurred in
connection with or arising from any injury to Tenant or for any damage to, or
loss (by theft or otherwise) of any of Tenant's Property, irrespective of the
cause of such injury, damage or loss (including the acts of negligence of
Tenant), but excluding Landlord's and Landlord's agents and employees,
negligence or willful misconduct. Any Building employees to whom any property
shall be entrusted by or on behalf of Tenant shall be deemed to be acting as
Tenant's agents with respect to such property and neither Landlord nor
Landlord's agents shall be liable for any loss of or damage to any such property
by theft or otherwise.

      17.2 Except as provided in Section 17.3(b), neither Landlord, nor any
agent or employee of Landlord, shall be liable for (a) any injury or damage to
any person or property resulting from fire, explosion, falling plaster, steam,
gas, electricity, dust, water or snow, or leaks from any part of the Building or
from the pipes, appliances or plumbing system, or from the roof, street or
subsurface or any other place or by dampness, or from any other cause
whatsoever, (b) any such damage caused by other occupants or persons in the
Building or by construction of any private, public or quasi-public work, or (c)
any latent defect in the Premises or the Building.

      17.3 (a) Tenant agrees to indemnify and save Landlord and Landlord's
agents and employees harmless of and from all losses, costs, liabilities,
claims, damages and expenses including reasonable counsel fees, penalties and
fines, incurred in connection with or arising from (a) any default by Tenant in
the observance or performance of any of the terms, covenants or conditions of
this Lease on Tenant's part to be observed or performed, or (b) the use or
occupancy or manner of use or occupancy of the Premises by Tenant or any person
claiming through or under Tenant, or (c) any acts, omissions or negligence of
Tenant or any such person, or the contractors, agents, servants, employees,
visitors or licensees of Tenant or any such person, in or about the Premises or
the Building either prior to, during, or after the expiration of, the Term
including any acts, omissions or negligence in the making or performing of any
improvements. If any action or proceeding shall be brought against Landlord or
Landlord's agents or employees based upon any such claim and if Tenant, upon
notice from Landlord, shall cause such action or proceeding to be defended at
Tenant's expense by counsel reasonably satisfactory to Landlord without any
disclaimer of liability by Tenant in connection with such claim, Tenant shall
not be required to indemnify Landlord and Landlord's agents or employees for
counsel fees in connection with such action or proceeding. The provisions of
this Section 17.3 shall survive the expiration or termination of this Lease.

            (b) Landlord agrees to indemnify and save Tenant and Tenant's agents
and employees harmless of and from all losses, cost, liabilities, claims,
damages and expenses including reasonable counsel fees, penalties and fines
incurred in connection with or arising from (i) any default by Landlord in the
observance of performance of any of the terms, covenants or conditions of this
Lease on Landlord's part to observed or performed; or (ii) any acts, omissions
or negligence of Landlord or any other person, or the contractors, agents,
servants or employees of Landlord or any such person in or about the Building
either prior to, during or after the expiration of the Term. If any action or
proceeding shall be brought against Tenant or Tenant's agents or employees based
upon such claim and if Landlord, upon notice from Tenant, shall cause such
action or proceeding to be defended at Landlord's expense by counsel reasonably
satisfactory to Tenant but without any disclaimer of liability by Landlord in
connection with such claim, Landlord shall not be required to indemnify Tenant
or Tenant's agents or

                                       23
<PAGE>

employees for counsel fees in connection with the proceeding or action. The
provisions of this Section 17.3(b) shall survive the expiration or termination
of this Lease.

                              ARTICLE 18 SURRENDER

      18.1 On the last day of the Term or upon any earlier termination of this
Lease, or upon any re-entry by Landlord upon the Premises, Tenant shall, at its
own expense, quit and surrender the Premises to Landlord, together with all
improvements which have been made upon the Premises (except as otherwise
provided for in this Lease, including but not limited to Article 9 above), in
broom clean, good order, condition and repair except (i) for ordinary wear and
tear; (ii) for damage by fire or other insured casualty and (iii) if, as of the
Commencement Date of this Lease, Tenant discovers that a component of the
Premises is not in good order, condition or repair and provided Tenant gives a
list to Landlord of such components within 180 days after the Commencement Date,
then Tenant will be required only to surrender such components in the condition
in which they were found at the Commencement Date and as they are described in
the list delivered to Landlord. Tenant shall remove from the Premises and the
Building all of all personal property and personal effects of all persons
claiming through or under Tenant and may remove items of Tenant's Property
including the items described on Exhibit J (and enhancements to and
replacements of such items as are identified to Landlord), and shall also remove
at Landlord's request, all vaults at the Premises, and, as set forth in Section
9.1 hereof, together with such other items as Landlord shall require Tenant to
remove, and shall, in each instance, pay the cost of repairing all damage to
the Premises and the Building occasioned by such removal.

      18.2 Any Tenant's Property or other personal property which shall remain
in the Premises after the Expiration Date or the date of sooner termination of
this Lease shall be deemed to have been abandoned and either may be retained by
Landlord as its property or may be disposed of in such manner as Landlord may
see fit at Tenant's cost and expense.

      18.3 If the Premises are not surrendered at the expiration of the Term,
Tenant shall (i) pay for the use and occupancy of the Premises at a rate equal
to two times the rate of Fixed Rent in effect immediately prior to the
expiration of the Term, on a daily basis, for each day until the date of
surrender of the Premises; and (ii) indemnify Landlord against any and all
damages, costs, expenses, loss or liability resulting from delay by Tenant in so
surrendering the Premises.

      18.4 Tenant's obligation under this Article shall survive the Expiration
Date or sooner termination of this Lease.

                ARTICLE 19 ASSIGNMENT, MORTGAGING AND SUBLETTING

      19.1 (a) Neither this Lease, nor the Term and estate hereby granted, nor
any part hereof or thereof, nor the interest of Tenant in any sublease or the
rentals thereunder, shall be assigned, mortgaged, pledged, encumbered or
otherwise transferred by Tenant, Tenant's legal representatives or successors in
interest by operation of law or otherwise, and neither the Premises, nor any
part thereof, shall be encumbered in any manner by reason of any act or omission
on the part of Tenant or anyone claiming under or through Tenant, or shall be
sublet or be used or occupied or permitted to be used or occupied, or for any
purpose other than as permitted by this Lease, without the prior consent of
Landlord in each case, which consent shall not be unreasonably withheld, delayed
or conditioned, except as expressly otherwise provided in this Article. In the
event that Tenant shall desire to assign this Lease or to sublease all or any

                                       24
<PAGE>

portion of the Premises, then Tenant shall submit in writing to Landlord the
name of the proposed assignee or subtenant, the nature and character of its
business, the terms and conditions of the proposed assignment or subletting,
information as to the financial responsibility and such other information as
Landlord may require. In the event that Tenant desires to assign this Lease,
then any proposed assignment must require Tenant's assignee to assume Tenant's
obligations from and after the effective date of an assignment. If Tenant shall
give Landlord notice of a desire to assign this Lease, or to sublet the entirety
of the Premises, Landlord shall be entitled to recapture the Premises or cancel
this Lease on 30 days' prior written notice thereof, and this Lease shall come
to an end on the date in such notice specified, with the same force and effect
as is such date were the date herein specified for the expiration hereof, and
the Fixed Rent, and Additional Rent shall be apportioned and adjusted as of the
effective date of such cancellation. Notwithstanding the foregoing, Tenant may
assign its entire interest under this Lease to a "Related Entity" (as defined
below) without the consent of Landlord provided that all of the following
conditions are satisfied: (i) Tenant is not in default of its obligations under
this Lease beyond any applicable grace or notice and cure periods; (ii) Tenant
shall remain fully liable for the obligations of the Tenant under this Lease;
and (iii) Tenant shall give Landlord written notice of at least thirty days
prior to the Effective Date of the proposed assignment. As used in this section,
the term "Related Entity" shall mean an entity which controls, is controlled by,
or is under common control with Tenant.

            (b) Any assignment of this Lease, or of the interest of Tenant
hereunder, or sublease as aforesaid, without full compliance with any and all
requirements set forth in this Lease shall be a breach of this Lease and a
default hereunder and shall, at Landlord's option, render any such purported
assignment or subletting null and void and of no force or effect

      19.2 If this Lease be assigned, whether or not in violation of the
provisions of this Lease, Landlord may collect rent from the assignee. If the
Premises or any part hereof be sublet or be used or occupied by anybody other
than Tenant, whether or not in violation of this Lease, Landlord may, after
default by Tenant and expiration of Tenant's time to cure such default, collect
rent from the subtenant or occupant. In either event, Landlord may apply the net
amount collected to the rents herein reserved, but no such assignment
subletting, occupancy or collection shall be deemed a waiver of any of the
provision of this Article, or the acceptance of the assignee, subtenant or
occupant as tenant, or a release by Tenant from the further performance by
Tenant of Tenant's obligations under this Lease. The consent of Landlord to an
assignment, mortgaging or subletting pursuant to any provision of this Lease
shall not in any way be considered to relieve Tenant from obtaining the express
consent of Landlord to any other or further assignment, mortgaging or
subletting. Tenant agrees to pay to Landlord reasonable counsel fees incurred by
Landlord in connection with any proposed assignment of Tenant's interest in this
Lease or any proposed subletting of the Premises or any part thereof. Neither
any assignment of Tenant's interest in this Lease nor any subletting, occupancy
or use of the Premises or any part thereof by any person other than Tenant, nor
any collection of rent by Landlord from any person other than Tenant as provided
in this Article, nor any application of any such rent as provided in this
Article, nor any application of any such rent as provided in this Article, shall
under any circumstances, relieve or release Tenant of its obligation fully to
observe and perform the terms, covenants and conditions of this Lease on
Tenant's part to be observed and performed.

      19.3 To the extent Tenant realizes any profit on any assignment or
sublease of all or any portion of the Premises, then 75 percent of said profit
shall be payable to Landlord. For purposes of this Section "profit" shall refer
to the difference between; (1) all payments made by an assignee or a subtenant
to Tenant as rent or otherwise under or in connection with said assignment or
sublease; and (2) the costs and expenses paid by Tenant in connection with said
assignment or sublease including the annual Fixed

                                       25
<PAGE>

Rent and Additional Rent payable hereunder with respect to the sublet space and
the reasonable brokerage, legal and alteration expenses, if any, incurred in
connection with said assignment or sublease. Promptly after such assignment or
the commencement of any such sublease Tenant shall deliver to Landlord a
statement of the expenses incurred in connection therewith and payments to
Landlord of Landlord's share of the profit in connection therewith shall be made
promptly after receipt thereof, in the case of an assignment and, in the case of
a sublease, monthly, as Additional Rent hereunder.

      19.4 (a) In case of a subletting approved by Landlord, a duly executed and
acknowledged original of the sublease shall be delivered to Landlord, the same
to provide that (i) such sublease is and shall be subject and subordinate to
this Lease and any then present or future modifications thereof; and (ii) in the
event of termination, re-entry or dispossess by Landlord under this Lease,
Landlord may, at its option, take over all of the right, title and interest of
Tenant, as sublessor, under such sublease, and such subtenant shall, at
Landlord's option, attorn to Landlord pursuant to the then executory provisions
of such sublease, except that Landlord shall not (A) be liable for any previous
acts or omissions of Tenant, as sublessor under such sublease; (B) be subject to
any offsets against Landlord or (C) be bound by any previous modification of
such sublease to which Landlord shall not have consented in writing or by any
previous prepayments of more than one month's rent.

            (b) In the case of any approved assignment or subletting, Tenant, as
assignor or as sublessor, as the case may be, shall remain liable for the
performance or observance of all of the terms and provisions on Tenant's part to
be performed or observed under this Lease.

      19.5 (a) If this Lease is assigned to any party pursuant to the Bankruptcy
Code or similar law, any and all monies or other consideration payable or
otherwise to be delivered in connection with such assignment shall be paid or
delivered to Landlord, shall be and remain the exclusive property of Landlord
and shall not constitute property of Tenant or of the estate of Tenant within
the Bankruptcy Code or similar law. Any and all monies and other consideration
constituting Landlord's property under the preceding sentence not paid or
delivered to Landlord shall be held in trust for the benefit of Landlord and
then be promptly paid or delivered to Landlord.

            (b) Any party to which this Lease shall be assigned pursuant to the
provisions of the Bankruptcy Code or similar law shall be deemed, without
further act or deed, to have assumed all of the obligations accruing under this
Lease on and after the date of such assignment. Any such assignee shall, upon
demand, execute and deliver to Landlord an instrument confirming such
assumption.

                     ARTICLE 20 SUBORDINATION AND ATTORNMENT

      20.1 This Lease, and all rights of Tenant hereunder, are and shall be
subject and subordinate in all respect to (a) all future ground leases,
overriding leases and underlying leases and/or grants of term of the Land and/or
the Building or the portion thereof in which the Premises are located in whole
or in part, (b) all mortgages and building loan agreements, including leasehold
mortgages and building loan agreements, which may now or hereafter affect the
Land and/or the Building (collectively, the "Superior Mortgages") whether or not
the Superior Mortgages shall also cover other lands and/or buildings and (c)
each and every advance made or hereafter to be made under the Superior Mortgages
and to all renewals, modifications, replacements substitutions and extensions of
the Superior Mortgages and spreaders and consolidations of the Superior
Mortgages. The provisions of this section shall be self-operative and no further
instrument of subordination shall be required as to any Superior Mortgage filed
subsequent to the effective date hereof but only if the holder of such Superior
Mortgage agrees in writing or the mortgage provides that for so long as Tenant
is not in default of its obligations set forth in this Lease beyond any

                                       26
<PAGE>

applicable notice and cure period, the holder of such Superior Mortgage will
not, in foreclosing against, or taking possession of the Premises or otherwise
exercising its right under the Superior Mortgage, disturb the Tenant's right of
possession under this Lease. In confirmation of such subordination, Tenant shall
within 10 days after receipt of a request for the same, provided the provisions
of the foregoing sentence are complied with to Tenant's benefit, execute and
deliver at its own cost and expense any instrument, in recordable form if
required, that Landlord or the holder of a Superior Mortgage or any of their
respective successors in interest may request to evidence such subordination.
Landlord shall obtain and deliver to Tenant a non-disturbance agreement from the
holder of the Superior Mortgage encumbering the Land and Building as of the date
hereof in form and substance reasonably satisfactory to Tenant.

      20.2 Subject to the provisions of Section 20.1 being complied with to
Tenant's benefit, if, at any time prior to the expiration of the Term, the
holder of a Superior Mortgage shall become the owner of the Building as a result
of foreclosure of its mortgage or conveyance of the Building, or become a
mortgagee in possession of the Land or the Building. Tenant agrees, at the
election and upon demand of any owner of the Land or the Building, or of the
holder of any Superior Mortgage (including a leasehold mortgagee) in possession
of the Land or the Building, to attorn from time to time to any such owner,
holder or lessee upon the then executory terms and conditions of this Lease,
provided that such owner, holder or lessee, as the case may be, shall then be
entitled to possession of the Premises. Such successor in interest to Landlord
shall not be bound by (i) any payment of rent or additional rent for more than
one month in advance, except prepayments in the nature of security for the
performance by Tenant of its obligations under the Lease, or (ii) any
amendment, modification or termination of this Lease made or entered into after
the date of execution of the Superior Mortgage without the consent of the holder
of the Superior Mortgage or such successor in interest whose name is disclosed
to Tenant or (iii) any offsets which may be asserted by the Tenant against
payments of rent as a result of any default by or claims against Landlord
hereunder arising prior to the date such successor takes possession of the
Premises or (iv) any obligation by Landlord as lessor hereunder to perform any
work or grant any concession without the mortgagee's express assumption of such
obligation to perform work or grant such concession. The foregoing provisions of
this Section shall inure to the benefit of any such owner, holder or lessee,
shall be self-operative upon any such demand, and no further instrument shall be
required to give effect to said provisions, although Tenant shall execute such
an instrument upon the request of the holder of a Superior Mortgage, provided
the provisions of Section 20.1 are complied with to Tenant's benefit.

      20.3 INTENTIONALLY OMITTED.

      20.4 Provided that the Tenant has been provided with notice of the name
and address of any holder of a Superior Mortgage (a "Mortgagee"), no notice from
the Tenant of any default by the Landlord in its obligations shall be valid, and
the Tenant shall not attempt to terminate this Lease, withhold Fixed Rent or
Additional Rent or exercise any other remedy which may arise under law by reason
of any such default, unless the Tenant first gives such notice to any Mortgagees
and provides such Mortgagees with notice of such default, and an opportunity to
cure the same within a period of time that shall be not less than the period
afforded to the Landlord to cure the default under the provisions of this Lease,
provided further that if the default by the Landlord is of such a nature that it
would, if left uncured, give rise to a right of termination by the Tenant of
this Lease, then the Tenant shall, prior to exercising any such termination
right, provide to the Mortgagee a second notice (which second notice shall be
given upon the expiration of the cure period initially applicable to the
default, after taking into account all applicable facts and circumstances)
stating the continuing nature of the default and providing to the Mortgagee an
additional thirty (30) day period within which to cure such default.

                                       27
<PAGE>

      20.5 Any Mortgagee may, at any time, by giving written notice to, and
without any further consent from, the Tenant, subordinate its mortgage to this
Lease, and thereupon the interest of the Tenant under this Lease shall
automatically be deemed to be prior to the lien of such mortgage without regard
to the relative dates of execution, delivery or filing thereof or otherwise.

      20.6 Landlord shall endeavor to have each Mortgagee provide in connection
with the application of insurance proceeds received by such Mortgagee, that, so
long as (i) Landlord is not in default of its obligations under the Superior
Mortgage and all financial covenants required by such Mortgagee have been and
are anticipated to continue to be satisfied; (ii) Tenant is not in default of
its obligations under this Lease; and (iii) Tenant will not exercise any right
it may have under the first sentence of Section 12.2 of this Lease by virtue of
the occurrence of such casualty to terminate the Lease such Mortgagee will
disburse such proceeds, in accordance with requirements set forth in the
Superior Mortgage (or other loan documents) for the repair and restoration of
the Building.

                     ARTICLE 21 ACCESS; CHANGE IN FACILITIES

      21.1 Landlord reserves the right, at any time without incurring any
liability to Tenant therefor, to make such changes in or to the Building and the
fixtures and equipment of the Building, as well as in the entrances,
passageways, halls, doors, doorways, corridors, elevators, escalators, stairs,
toilets and other public parts of the Building as it may deem necessary or
desirable, provided any such change does not (x) deprive Tenant of access to the
Premises; (y) materially or unreasonably interfere with the use of the Premises
or the conduct of business therein; nor (z) reduce the usable area of the
Premises in excess of one percent (1%) of the total rentable area thereof so
long as such reduction shall not materially, adversely effect the Tenant's
current use (with an appropriate adjustment in Fixed Rent due to such reduction
in the area of the Premises).

      21.2 Tenant shall permit Landlord to install, use and maintain pipes,
ducts and conduits within or through the Premises, or through the walls, columns
and ceilings therein, provided that the installation work is performed at such
times and by such methods as will not reduce the usable space in the Premises or
unreasonably interfere with Tenant's use and occupancy of the Premises, or
damage the appearance thereof.

      21.3 Landlord or Landlord's agents shall have the right to enter the
Premises at all times for any of the purposes specified in this Article and (a)
to examine the Premises or for the purpose of performing any obligation of
Landlord or exercising any right or remedy reserved to Landlord in this Lease;
(b) to exhibit the Premises to a prospective purchaser, mortgagee, ground lessor
of the Building, or others and during the last six months of the lease term to
exhibit the Premises to prospective tenants; (c) make such repairs, alterations,
improvements or additions or to perform such maintenance as Landlord may deem
necessary or desirable; (d) to take all materials into and upon the Premises
that may be required in connection with any such repairs, alterations
improvements, additions or maintenance; and (e) to alter, renovate and decorate
the Premises if Tenant shall have removed all or substantially all of Tenant's
Property from the Premises. Notwithstanding the foregoing, except in emergencies
or Tenant's default hereunder, all entries by Landlord under this Section shall
be, after notice to Tenant, at reasonable times and shall be conducted in
accordance with Tenant's customary rules and regulations concerning access to
the Premises including, but not limited to labs, research and administrative
offices located therein and so as not to unduly or unseasonably, interfere with
Tenant's use and occupancy of the Premises.

      21.4 The exercise of any right reserved to Landlord in this Article shall
not constitute an actual or constructive eviction, in whole or in part, or
entitle Tenant to any abatement or diminution of rent

                                       28
<PAGE>

(except as specifically provided herein), or relieve Tenant from any of its
obligations under this Lease, or impose any liability upon Landlord or
Landlord's agents, or upon the holder of a Superior Mortgage.

                         ARTICLE 22 INABILITY TO PERFORM

      22.1 This Lease and the obligations of Tenant to pay rent and perform all
of the terms, covenants and conditions on the part of Tenant to be performed
shall in no way be affected, impaired or excused because Landlord, due to the
occurrence of an event of force majeure (as set forth in Article 32 hereof) is
(a) unable to fulfill any of its obligations under this Lease or (b) unable to
supply or delayed in supplying any service expressly or impliedly to be
supplied, or (c) unable to make or delayed in making any repairs, replacements,
additions, alterations or decorations or (d) unable to supply or delayed in
supplying any equipment or fixtures. Landlord shall in each instance exercise
commercially reasonable diligence to effect performance when and as soon as
possible.

             ARTICLE 23 PREJUDGMENT REMEDY, REDEMPTION, COUNTERCLAIM
                                 AND JURY TRIAL

      23.1 Tenant, for itself and for all persons claiming through or under it,
hereby acknowledges that this Lease constitutes a commercial transaction as such
term is used and defined in Chapter 903 of the Connecticut General Statutes, and
hereby expressly waives any and all rights which are or may be conferred upon
Tenant by said Act to any notice or hearing prior to a prejudgment remedy, and
by any present or future law to redeem the Premises, or to any new trial in any
action or ejection under any provisions of law, after reentry thereupon, or upon
any part thereof, by Landlord, or after any warrant to dispossess or judgment in
ejection. If Landlord shall acquire possession of the Premises by summary
proceedings, or in any other lawful manner without judicial proceedings, it
shall be deemed a reentry within the meaning of that word as used in this Lease.
In the event that Landlord commences any summary proceedings or action for
nonpayment of rent or other charges provided for in this Lease, Tenant shall not
interpose any non-compulsory counterclaim of any nature or description in any
such proceeding or action. Tenant and Landlord both waive a trial by jury of any
or all issues arising in any action or proceeding between the parties hereto or
their successors, under or connected with this Lease, or any of its provisions.

                               ARTICLE 24 WAIVERS

      24.1 The failure of Landlord to insist in any one or more instances upon
the strict performance of any one or more of the arguments, terms, covenants,
conditions or obligations of this Lease, or to exercise any right, remedy or
election herein contained, shall not be construed as a waiver or relinquishment
for the future of the performance of such one or more obligations of this Lease
or of the right to exercise such election, but the same shall continue and
remain in full force and effect with respect to any subsequent breach, act or
omission whether of a similar nature or otherwise. The manner of enforcement or
the failure of Landlord to enforce any of the Rules and Regulations against
Tenant and/or any other tenant in the Building shall not be deemed a waiver of
any such Rules and Regulations.

      24.2 The following specific provisions of this Section shall not be deemed
to limit the generality of the foregoing provisions of this Article:

                                       29
<PAGE>

      (a) No agreement to accept a surrender of all or any part of the Premises
shall be valid unless in writing and signed by Landlord. No delivery of keys
shall operate as a termination of this Lease or a surrender of the Premises.

      (b) The receipt or acceptance by Landlord of rents with knowledge of
breach by Tenant of any term, covenant or condition of this Lease shall not be
deemed a waiver of such breach.

      (c) No payment by Tenant or receipt by Landlord of a lesser amount than
the correct Fixed Rent or Additional Rent shall be deemed to be other than a
payment on account, nor shall any endorsement or statement on any check or any
letter accompanying any check or payment be deemed to effect or evidence an
accord and satisfaction, and Landlord may accept such check or payment without
prejudice to Landlord's right to recover the balance or pursue any other remedy
in this Lease or at law provided.

                           ARTICLE 25 QUIET ENJOYMENT

      25.1 If, and so long as Tenant pays the Fixed Rent and Additional Rent and
keeps and performs each and every term. covenant and condition herein contained
on the part and on behalf of Tenant to be kept and performed, Tenant shall
lawfully and quietly hold, occupy and enjoy the Premises during the Term of this
Lease without hinderance or molestation by Landlord, subject to the terms,
covenants, and conditions of this Lease and the Superior Mortgages (provided,
with regard to the Superior Mortgages, Tenant shall have the benefit of the
right of non-disturbances granted herein and of any non-disturbance agreement
delivered to Tenant by any holder of a Superior Mortgage).

                       ARTICLE 26 ENVIRONMENTAL COMPLIANCE

      26.1 Tenant hereby covenants to Landlord that Tenant shall (a) (i) comply
with all Laws (as defined below) applicable to the discharge, generation,
manufacturing, removal, transportation, treatment, storage, disposal and
handling of Hazardous Materials or Wastes (as defined below) as apply to the
activities of the Tenant, its directors, officers, employees, agents,
contractors, subcontractors, licensees, invitees, sublessees, assignees,
successors and assigns at the Property (together with Tenant, the "Tenant
Parties") and, without limiting the generality of the foregoing, obtain and
comply with any and all required discharge permits for the discharge of
laboratory waste, and prior to the expiration or termination of this Lease, use
commercially reasonable efforts to complete the closure of any Hazardous Waste
Storage Area in accordance with all applicable laws, rules and regulations; (ii)
promptly remove any Hazardous Materials or Wastes caused or generated by the
Tenant Parties from the Premises in accordance with all applicable Laws and
orders of governmental authorities having jurisdiction; (iii) pay or cause to be
paid all costs associated with such removal of such Hazardous Materials or
Wastes generated by Tenant or the Tenant Parties including any remediation and
restoration of the Premises; and (iv) indemnify Landlord from and against all
losses, claims and costs arising out of the migration of Hazardous Materials or
Wastes caused or generated by the Tenant Parties from or through the Premises
into or onto or under other portions of the Building or the Property or other
properties; (b) keep the Property free of any lien imposed pursuant to any
applicable Law in connection with the existence of Hazardous Materials or Wastes
in or on the Premises caused or generated by Tenant or the Tenant Parties; (c)
not install or permit to be installed or to exist in the Premises any asbestos,
asbestos-containing materials, urea formaldehyde insulation or any other
chemical or substance which has been determined to be a hazard to health and
environment, the installation, presence, use or existence of which would be in
or cause a violation of any applicable Law; (d) not cause or permit to exist, as
a result of an intentional or unintentional act or omission on the part of
Tenant, any Tenant Parties or any occupant of

                                       30
<PAGE>

the Premises, a releasing, spilling, leaking, pumping, emitting (other than from
one containment area to another), pouring, discharging, emptying or dumping of
any Hazardous Materials or Wastes onto the Premises, the Building or the Land;
(e) identify on Exhibit C all Hazardous Materials or Wastes currently used by
Tenant and shall notify Landlord of any changes or addition to the Hazardous
Materials or Wastes so used; (f) give all notifications and prepare all reports
required by Laws or any other law with respect to Hazardous Materials or Wastes
caused or generated by the Tenant Parties existing on, released from or emitted
from the Premises (and shall give copies of all such notifications and reports
to Landlord); (g) promptly notify Landlord in writing of any release, spill,
leak, emittance, pouring, discharging, emptying or dumping of Hazardous
Materials or Wastes known to Tenant in or on the Premises; (h) if Landlord has a
reasonable basis of belief that Tenant, the Tenant Pates permitted a release or
spill of Hazardous Materials or Wastes to occur, pay for periodic environmental
monitoring by Landlord as well as subsurface testing paid as Additional Rent;
and (i) promptly notify Landlord in writing of any summons, citation, directive,
notice, letter or other communication, written or oral, from any local, state or
federal governmental agency, or of any claim or threat of claim known to Tenant,
made by any third party relating to the presence or releasing, spilling,
leaking, pumping, emitting, pouring, discharging, emptying or dumping of any
Hazardous Materials or Wastes caused or generated by the Tenant Parties onto the
Premises. In addition to the foregoing, Tenant shall be responsible for and bear
all costs in connection with the treatment and discharge of its laboratory waste
and waste water disposal. Notwithstanding anything to the contrary set forth in
this Lease, Tenant shall not be responsible or liable for any Hazardous
Materials or Waste located at, in, or around the Premises which was (i) released
or generated prior to the Commencement Date (unless released or generated by
Tenant during its early access to and occupancy of the Premises); or (ii) was
released or generated by Landlord, Arch or any other tenant.

      Tenant's obligation to close the Hazardous Waste Storage Area, at Tenant's
sole cost and expense, shall survive termination of the Lease. Tenant agrees
that, in connection therewith, and as security for Tenant's obligation to close
any Hazardous Waste Storage Area then, on Landlord's request made prior to or
within 10 business days after than the Expiration Date, (or if the Lease is
sooner terminated, on the termination date, Tenant shall deposit with Landlord a
reasonable sum, not to exceed $50,000, which Landlord shall be entitled to
continue to hold as security for the proper and lawful closure of the Hazardous
Waste Storage Area, the "Closure Obligation"). In lieu of cash, Tenant may
provide Landlord with an unconditional, irrevocable, assignable letter of
credit, (the "Letter of Credit") for all or a portion of such amount. In the
event Tenant furnishes the Letter of Credit, the Letter of Credit shall be on
the following terms and conditions: (i) issued by a commercial bank acceptable
to Landlord, which bank must have an office in New Haven, Connecticut; (ii)
having a term which shall have an expiration date not sooner than the date which
is five (5) years from the Expiration Date (as such date may be extended by
virtue of Tenant exercising its right to extend the Term) or sooner termination
date, however, if the Letter of Credit has an earlier expiration date, it shall
contain a so-called "evergreen clause"; (iii) available for negotiation by
draft(s) at sight accompanied by a statement signed by Landlord stating that the
amount of the draw represents funds due to Landlord (or its successors and
assigns) due to the failure of Tenant to perform its Closure Obligation or (iv)
be otherwise on terms and conditions reasonably satisfactory to Landlord. It is
agreed that in the event Tenant fails to perform its Closure Obligation,
Landlord may draw upon the Letter of Credit or upon the funds held on account as
the Security Deposit to the extent required to perform the same. In the event
that Tenant shall fully and faithfully perform its Closure Obligation (as shall
be evidenced by a sign-off or other definitive communication from applicable
Governmental Authorities, the Letter of Credit and/or funds on deposit with
Landlord shall be returned to Tenant. Tenant further covenants that it will not
assign or encumber or attempt to assign or encumber the Letter of Credit or any
funds on deposit and that neither Landlord nor its successors or

                                       31
<PAGE>

assigns shall be bound by any such assignment, encumbrance, attempted assignment
or attempted encumbrance.

      26.2 The term "Hazardous Materials or Wastes" shall mean any hazardous or
toxic materials, pollutants, chemicals, or contaminants, including without
limitation asbestos, asbestos-containing materials, urea formaldehyde foam
insulation, polychlorinated biphenyls (PCBS) and petroleum products as defined,
determined or identified as such in any Laws, as hereinafter defined. The term
"Laws" means any federal, state, county, municipal or local laws, rules or
regulations (whether now existing or hereinafter enacted or promulgated)
including, without limitation, the Clean Water Act, 33 U.S.C. ss. 1251 et seq.
(1972), the Clean Air Act, 42 U.S.C. ss. 7401 et seq. (1970), the Comprehensive
Environmental Response, Compensation and Liability Act of 1980, as amended, 42
U.S.C. Subsection 1802, and The Resource Conservation and Recovery Act, 42
U.S.C. Subsection 6901 et seq., any similar state laws, as well as any judicial
or administrative interpretation thereof, including any judicial or
administrative orders or judgments.

      26.3 Tenant hereby agrees to defend, indemnify and hold harmless Landlord,
its employees, agents, contractors, subcontractors, licensees, invitees,
successors and assigns from and against any and all claims, losses, damages,
liabilities, judgements, costs and expenses (including, without limitation,
attorneys' fees and costs incurred in the investigation, defense and settlement
of claims or remediation of contamination) incurred by such indemnified parties
as a result of or in connection with the presence at or removal of Hazardous
Materials or Wastes caused or generated by Tenant or any of the Tenant Parties
from the Premises or as a result of or in connection with activities prohibited
under this Article 26. Tenant shall bear, pay and discharge, as and when the
same become due and payable, any and all such judgments or claims for damages,
penalties or otherwise against such indemnified parties, shall hold such
indemnified parties harmless against all claims, losses, damages, liabilities,
costs and expenses, and shall assume the burden and expense of defending all
suits, administrative proceedings, and negotiations of any description with any
and all persons, political subdivisions or government agencies arising out of
any of the occurrences set forth in this Paragraph 26. The provisions of this
Section shall survive termination of this Lease.

                              ARTICLE 27 BROKERAGE

      27.1 Tenant represents that in the negotiation of this Lease it dealt with
no real estate broker or salesman other than Cushman & Wakefield of Connecticut,
Inc. and CB Richard Ellis, Inc. Tenant shall indemnify Landlord and hold
Landlord harmless from any and all losses, damages and expenses arising out of
any inaccuracy or alleged inaccuracy of the above representation, including
court costs and attorneys' fees. Landlord shall have no liability for brokerage
commissions arising out of a sublease by Tenant and Tenant shall and does hereby
indemnify Landlord and hold harmless from any and all liability for brokerage
commissions arising out of any such sublease. Tenant's indemnity shall also
cover all fees, costs and expenses, including attorneys' fees, which Landlord
incurs to defend against any such claim (which Tenant shall pay upon demand).
The provisions of this Article 27 shall survive the expiration or termination of
this Lease.

                               ARTICLE 28 NOTICES

      28.1 All notices, demands or communications given under this Lease shall
be sent to the addresses set forth above (except that from and after the
Commencement Date, Tenant's notice address shall be 350 Knotter Drive, Cheshire,
Connecticut 06410) or at such other addresses as the parties may

                                       32
<PAGE>

designate by written notice and shall be hand delivered or sent by private
overnight courier service or by prepaid registered or certified mail, return
receipt requested, and shall be deemed given on the date delivered or, if
refused, the date of such refusal.

             ARTICLE 29 ESTOPPEL CERTIFICATE, MEMORANDUM; FINANCIALS

      29.1 At any time and from time to time within ten (10) days' prior of
delivery of written notice by Landlord or Tenant to the other, Landlord and
Tenant shall execute, acknowledge and deliver to the other a statement in
writing in form satisfactory to Landlord certifying that this Lease is
unmodified and in full force and effect (or if there have been modifications,
that the same is in full force and effect as modified and stating the
modifications), and the dates to which the Fixed Rent and Additional Rent have
been paid in advance, if any, stating whether there are any offsets to the
Tenant's obligation to pay rent thereunder and describing them, if any, and
stating whether or not to the best knowledge of the signer of such certificate
(who shall be a duly authorized officer or signatory of Tenant) Landlord is in
default in performance of any term, covenant or condition contained in this
Lease, and if so, specifying each such default of which the signer may have
knowledge, it being intended that any such statement delivered pursuant hereto
may be relied upon by any prospective purchaser of the Land and the Building or
any part thereof or of the interest of Landlord in any part thereof, by any
mortgagee or prospective mortgagee thereof, by any lessor or prospective lessor
thereof, or by any lessee or prospective lessee thereof, or by any prospective
assignee of any mortgagee thereof.

      29.2 At the request of either party. Landlord and Tenant shall promptly
execute, acknowledge and deliver a memorandum with respect to this Lease
sufficient for recording. Such memorandum shall not state the Fixed Rent. Such
memorandum shall not in any circumstances be deemed to change or otherwise
affect any of the terms, covenants and conditions of this Lease.

      29.3 Tenant, and each and every assignee, sublessee, successor or assign
of Tenant, shall deliver to Landlord, with reasonable promptness, but in no
event later than ninety (90) days after the close of each fiscal year of such
entity, a copy of such entity's audited year end financial statements and cash
flow analysis, each prepared in accordance with generally accepted accounting
principles, which shall be certified by such entity's chief financial officer as
being true, accurate and complete in all material respects. Upon written request
by Tenant, Landlord shall enter into a commercially reasonable confidentiality
agreement covering any confidential information that is disclosed by Tenant.

                            ARTICLE 30 PARTIES BOUND

      30.1 The terms, covenants and conditions contained in this Lease shall
bind and benefit the successors and assigns of the parties with the same effect
as if mentioned in each instance where a party is named or referred to except
that no violation of the provisions of Article 19 shall operate to vest any
rights in any successor or assignee of Tenant and that the provisions of this
Article shall not be construed as modifying the conditions of limitation
contained in Article 14.

      30.2 The obligations of Landlord under this Lease shall no longer be
binding upon Landlord named herein after the sale, assignment or transfer by
Landlord named herein (or upon any subsequent landlord) of its interest in the
Building as owner or lessee, and in the event of such sale, assignment or
transfer, such obligations shall thereafter be binding upon the grantee,
assignee or other transferee of such interest, and any such grantee, assignees
or transferee, by accepting such interest, shall be deemed to have assumed such
obligations. A lease of Landlord's entire interest in the Building shall be
deemed a

                                       33
<PAGE>

transfer for the purposes of this Section, provided the transferee assumes the
obligations of the Landlord hereunder.

      30.3 In connection with the provisions of this Lease and the obligations
and covenants of Landlord herein set forth, Tenant shall look solely to the
estate and property of such Landlord in the Land and Building for the
satisfaction of Tenant's remedies, for the collection of a judgement (or other
Judicial process) requiring the payment of money by Landlord in the event of any
default or breach by Landlord with respect to any of the terms, covenants and
conditions of this Lease to be observed and/or performed by Landlord, and no
other property or assets of such Landlord shall be subject to levy, execution or
other enforcement procedure for the satisfaction of Tenant's remedies.

             ARTICLE 31 ENTIRE AGREEMENT; NO OTHER REPRESENTATIONS;
               GOVERNING LAW; SEPARABILITY; TIME IS OF THE ESSENCE

      31.1 This Lease contains the entire agreement between the parties and all
prior negotiations and agreements are merged in this Lease. This Lease may not
be changed, modified or discharged, in whole or in part, except by a written
instrument executed by the party against whom enforcement of the change,
modification or discharge is sought.

      31.2 Tenant expressly acknowledges that neither Landlord nor Landlord's
agents has made or is making, and Tenant, in executing and delivering this
Lease, is not relying upon any warranties, representations, promises or
statements, except to the extent that the same are expressly set forth in this
Lease, and no rights, easements or licenses are or shall be acquired by Tenant
by implication or otherwise unless expressly set forth in this Lease.

      31.3 This Lease shall be governed in all respects by the laws of the State
of Connecticut.

      31.4 Each covenant and agreement in this Lease shall be construed to be a
separate and independent covenant and agreement and the breach of any such
covenant or agreement by Landlord or Tenant shall not discharge or relieve the
other from its obligation to perform every covenant and agreement of this Lease
to be performed by it. If any term or provision of this Lease or any application
thereof shall be invalid or unenforceable, the remainder of this Lease and any
other application of such term shall not be affected thereby.

      31.5 The parties agree that with respect to payments to be made and
obligations to be performed under this Lease, time is of the essence.

                            ARTICLE 32 FORCE MAJEURE

      32.1 Landlord and Tenant shall be excused for the period of any delay in
the performance of any obligations hereunder, when prevented from so doing by
cause or causes beyond Landlord's or Tenant's, as the case may be, reasonable
control which shall include, without limitation, all labor disputes, civil
commotion, war, war-like operations, invasion, rebellion, hostilities, military
or usurped power, sabotage, governmental regulations or controls, fire or other
casualty, inability to obtain any material or services through Acts of God
(force majeure) provided:

                                       34
<PAGE>

            (a) Nothing contained in this Article 32 or elsewhere in this Lease
shall be deemed to excuse or permit any delay in the payment of any sums of
money required hereunder, or any delay in the cure of any default which may be
cured by the payment of money;

            (b) Neither Landlord nor the Tenant shall be entitled to rely upon
this Article 32 unless it shall advise the other in writing of the existence of
any force majeure event preventing the performance of any obligation of the
Landlord or the Tenant, as the case may be, within five (5) days after the
commencement of the force majeure; and

            (c) No reliance by the Tenant or the Landlord upon this Paragraph 32
shall limit or restrict in any way the Landlord's or Tenant's, as applicable,
right to self-help as provided in this Lease.

            (d) Landlord and Tenant shall each use commercially reasonable
efforts to alleviate or curtail any force majeure occurrence.

                           ARTICLE 33 EXTENSION OPTION

      33.1 At the expiration of the original term hereof, if this Lease shall be
in full force and effect and if the Tenant shall not be in default (beyond any
applicable notice and grace period) of any of the terms, conditions, covenants
and provisions hereof, at the time of exercise of the option and as of the
commencement of the applicable extended term, Tenant shall have the right to
extend the term of this Lease for three (3) additional terms of five (5) years,
provided that it gives Landlord at least twelve (12) months' advance written
notice of its exercise of each such extended term option, time being of the
essence. The Fixed Rent (as described in Section 4 of this Lease) to be paid by
Tenant during such extended term shall be payable at the rates and in the
amounts set forth on Exhibit B. The Fixed Rent during such extended term shall
be paid at the times and in the manner provided in the Lease for payment of
Fixed Rent, but in the amount set forth on Exhibit B. Tenant occupancy during
such extended term shall be governed by all of the other terms, conditions,
covenants and provisions of this Lease, including, with respect to payment of
Additional Rent, and except as expressly otherwise provided in this Article, and
as this Lease shall have hereafter been amended, if at all.

                           ARTICLE 34 SECURITY DEPOSIT

      34.1 Tenant shall deposit with Landlord upon execution of this Lease the
sum of Two Hundred Thousand and 00/100 Dollars ($200,000.00), as a deposit
toward the total amount of the Security Deposit to be delivered to Landlord and
which Landlord shall be entitled to continue to hold as security for the
faithful performance and observance by Tenant of the terms, provisions, and
conditions of this Lease. The total amount of the Security Deposit to be
delivered to Landlord shall be determined and deposited with Landlord as of the
Rent Commencement Date. The amount of the Security Deposit is to be a function
of the amount of the Allowance utilized by Tenant. In the event Tenant utilizes
the entirety of the $30.00 per square foot Allowance, the amount of the Security
Deposit shall be One Million and 00/100 Dollars ($1,000,000.00) and if Tenant
does not use any of the Allowance, the amount of the Security Deposit shall be
Two Hundred Thousand and 00/100 Dollars ($200,000.00). If Tenant uses part of
the Allowance, the amount of the Security Deposit will be equal to the product
of (i) the percentage of the $30.00 per square foot Allowance used by Tenant
times (ii) $ 1,000,000.00, but in no event will the amount of the Security
Deposit be less than $200,000.00. (For example, if Tenant uses $20.00 per square
foot, then the Security Deposit shall be equal to (i) $20 / $30 (or 66.67) times
(ii) $1,000,000.00, or $666,666.67). As of the Rent Commencement Date, Landlord
and Tenant shall apply the $200,000.00 deposit toward the total amount of the
Security Deposit and Tenant shall, within 5 Business Days, deliver

                                       35
<PAGE>

any amount necessary to equal the total amount of the Security Deposit. In lieu
of cash, Tenant may provide Landlord with an unconditional, irrevocable,
assignable letter of credit. (the "Letter of Credit") for all or a portion of
such amount. In the event Tenant furnishes the Letter of Credit, the Letter of
Credit shall be on the following terms and conditions: (i) issued by a
commercial bank acceptable to Landlord, which bank must have an office in New
Haven, Connecticut; (ii) having a term which shall have an expiration date not
sooner than 60 days after the Expiration Date (and, if the Term is extended in
accordance with the terms hereof, an expiration date 60 days after the
expiration of each extended period), however, if the Letter of Credit has an
earlier expiration date, it shall contain a so-called evergreen clause"; (iii)
available for negotiation by draft(s) at sight accompanied by a statement signed
by Landlord stating that the amount of the draw represents funds due to Landlord
(or its successors and assigns) due to the failure of Tenant to pay Fixed Rent
and/or Additional Rent when due or otherwise perform its obligations under this
Lease and (iv) be otherwise on terms and conditions satisfactory to Landlord. It
is agreed that in the event Tenant defaults beyond any applicable notice and
cure period in respect of any of the terms, provisions, covenants, and
conditions of this Lease, including, but not limited to, the payment of Fixed
Rent and Additional Rent, Landlord may draw upon the Letter of Credit or upon
the funds held on account as the Security Deposit to the extent required for the
payment of any Fixed Rent and Additional Rent or any other sum as to which
Tenant is in default or for any sum which Landlord may expend or may be required
to expend by reason of Tenant's default (beyond applicable notice and cure
periods) in respect of any of the terms, provisions, covenants, and conditions
of this Lease, including, but not limited to, any damages or deficiency accrued
before or after summary proceedings or other re-entry by Landlord. In the event
that Tenant shall fully and faithfully comply with all of the terms, provisions,
covenants, and conditions of this Lease, the Letter of Credit and/or funds on
deposit with Landlord shall be returned to Tenant within 60 days after the
Expiration Date (as if may be extended) and after delivery of entire possession
of the Premises to Landlord. Tenant further covenants that it will not assign or
encumber or attempt to assign or encumber the Letter of Credit or any funds on
deposit and that neither Landlord nor its successors or assigns shall be bound
by any such assignment, encumbrance, attempted assignment or attempted
encumbrance. In the event Landlord draws upon the Letter of Credit or on funds
on deposit as the Security Deposit, Tenant shall provide a new irrevocable
letter of credit (on the terms set forth above) or with cash in the amount of
the amount so drawn within seven (7) days after Landlord notifies Tenant of the
draw or withdrawal so that at all times the total amount of Letters of Credit
and/or funds in the account held by Landlord shall be equal to the aggregate
Security Deposit. If the amount of the Security Deposit exceeds, $200,000.00
then, provided that Tenant is not in default, beyond any applicable notice and
grace period, of its obligations under this Lease at any time during each
applicable Lease Year, then commencing on the expiration of the fifth Lease Year
and at the end of each Lease Year thereafter, the amount of the Security Deposit
shall be reduced by $200,000.00, but in no event will the Security Deposit be
reduced below $200,000.00.

      34.2 In the event of a sale of the Building or leasing of the Building, or
of the portion of the Building in which the Premises are located, Landlord shall
have the right to transfer the Security Deposit to the vendee or Lessee and
Landlord shall thereupon be released by Tenant from all liability for the return
of the Security Deposit, and Tenant agrees to look solely to the new landlord
for the return of the Security Deposit, and it is agreed that the provisions
hereof shall apply to every transfer or assignment made of the Security Deposit
to a new landlord.

                           ARTICLE 35 LANDLORD DEFAULT

      35.1 In the event Landlord shall (i) file or have filed against it a
petition or case under any section or chapter of the United States Bankruptcy
Code, as amended, or any similar law or statute of the United States or any
state and such petition or case is not discharged within 90 days or (ii) default
in the

                                       36
<PAGE>

observance or performance of any term, covenant, or condition of this Lease on
Landlord's part to be observed and performed, beyond any applicable notice or
grace period, Tenant may pursue such rights and remedies as are available to it
in law or in equity.

                              ARTICLE 36 EXPANSION

      36.1 Attached hereto as Exhibit H is a preliminary plan to outline
expansion possibilities that the Landlord may make available to Tenant. The
ability of Landlord to make any expansion space available to Tenant is subject
to, among other things (i) Tenant not being in default (beyond applicable notice
or cure period(s) of its obligations under this Lease and (ii) Landlord's
ability to obtain (y) all necessary permits and approvals and (z) financing. If
any expansion option is pursued, the parties shall, in good faith, negotiate an
amendment of the terms of this Lease (including the amount of Fixed Rent and
Additional Rent payable by Tenant) to apply to the expansion area, and Landlord
shall, in good faith, seek the financing necessary to accomplish the expansion.

      Plan A shows a possible expansion of the Building in an area located at
the southeast corner of the Building. Tenant shall have the exclusive right,
during the initial Term of the Lease (but not during an extension term of the
Lease Term), to request that Landlord pursue this expansion alternative.

      Plan B shows a possible expansion along the western side of the Building.
Tenant shall have the right during the Initial Term (but not during any
extension term) to request that Landlord pursue this expansion alternative.

      If the parties are unable to agree on the terms under which Landlord would
provide expansion space to Tenant, then Landlord shall be under no obligation to
pursue an expansion. Furthermore, Landlord's inability to expand the Building
under Plan A or Plan B, shall not constitute a default by Landlord under this
Lease.

      The exclusive nature of the Tenant's right, as described above with regard
to Plan A, in this Article 36, means that Landlord will take not action as to
the Land or Building during the initial Term that would preclude Tenant from
seeking the full benefit of the expansion option available to it under Plan A.

      The expansion rights set forth above are personal to Tenant and to any
assignee that is a Related Entity (as set forth in Article 19 of this Lease) and
shall automatically terminate and become null, void and of no force and effect
upon the earlier to occur of (i) the expiration or termination of the Lease by
Landlord or pursuant to Law; (ii) the termination or surrender of Tenant's right
of possession to the Premises; (iii) the assignment of this Lease by Tenant;
(iv) the sublease by Tenant of more than 50% of the rentable area of the
Premises, which sublease(s) have expiration dates within six months of the
termination date or expiration date of this Lease; (v) the failure of Tenant to
timely and/or properly exercise the option set forth above.

      Subject to the requirements of law, including the obtaining of necessary
permits and approvals from applicable Governmental Authorities, and the
restrictions and conditions set forth in the declarations attached hereto as
Exhibit M, the parties shall negotiate in good faith to arrive at a design,
choice of materials, and specifications for the expansion area that will,
substantially, meet the needs of Tenant.

                                       37
<PAGE>

              ARTICLE 37 RIGHT OF FIRST OFFER FOR THE ARCH PREMISES

      37.1 In the event that at any time during the Term of this Lease, as it
may be extended, the Premises shown on Exhibit A as the Arch Chemical Premises
becomes or is to become available for rental and Landlord wishes to lease such
space to any person other than the then current occupant(s) thereof (if any),
and, in the further event, that Tenant is not then in default (beyond any
applicable grace or notice period) of its obligations to Landlord under this
Lease, Landlord shall, before entering into a Lease for all or any portion of
such space, make a written offer to lease the same to Tenant ("Landlord's
Offer") stating the Rent and Additional Rent that Landlord will accept and all
other material terms and conditions on which it would be willing to lease such
space to Tenant. If within twenty (20) business days after receipt of Landlord's
Offer, Tenant agrees in writing to lease such space, Landlord and Tenant will
use commercially reasonable efforts to execute a lease or an amendment to this
Lease for such space within forty-five (45) business days after Landlord's
receipt of Tenant's notice of its election. If such notice of acceptance by
Tenant is not so given, the Landlord shall be free to lease such space to a
third party at an effective rent (which shall include Base Rent, Additional Rent
and other monetary considerations) not substantially more favorable to said
third party (i.e., Landlord shall not offer an effective rent that is less than
95% of the effective rent offered to Tenant) than that set forth in Landlord's
Offer. In any case in which Tenant shall waive said right or if Tenant shall
have failed to timely exercise such right, then Tenant shall, on request of
Landlord, execute and deliver in recordable form an instrument indicating such
waiver or expiration, which instrument shall be conclusive in favor of all
persons relying thereon in good faith. This Right of First Offer is personal to
the named Tenant and to any assignee that is a Related Entity (as set forth in
Article 19 of this Lease) and shall automatically terminate and become null,
void and of no force and effect upon the earlier to occur of (i) the expiration
or termination of this Lease by Landlord or pursuant to Law: (ii) the
termination or surrender of Tenant's right to possession of the Premises; (iii)
the assignment of this Lease by Tenant (to other than a Related Entity); (iv)
the sublease by Tenant of more than 50% of the rentable area of the Premises,
which sublease(s) have expiration dates within six months of the Termination
Date or Expiration Date of this Lease (to other than a Related Entity) ; or (v)
the failure of Tenant to timely and properly exercise its rights under this
provision.

           ARTICLE 38 RIGHT OF FIRST OFFER AS TO THE LAND AND BUILDING

      38.1 In the event that Landlord shall decide to sell the Land and the
Building, provided that (i) this Lease is in full force and effect and (ii)
Tenant is not then in default (beyond any applicable grace or notice period),
then the Landlord shall negotiate in good faith with the Tenant (to the
exclusion of others), for up to thirty (30) business days from the date of
written notice of Landlord's intent to sell, for the sale of the Land and
Building to Tenant, provided, however, Landlord shall have no liability to the
Tenant, nor shall the Tenant's obligations under this Lease be in any way
affected, in the event that the Landlord and Tenant do not agree on terms for a
sale of the Land and Building to the Tenant, for any reason. In any case in
which Landlord and Tenant do not agree on terms for the sale of the Land and
Building to Tenant, within such thirty (30) business day period, then Tenant
shall, on request of Landlord, execute and deliver in recordable form an
instrument indicating such failure or inability, which instrument shall be
conclusive in favor of all persons relying thereon in good faith. This right of
first offer is personal to the named Tenant and to any assignee that is a
Related Entity (as set forth in Article 19 of this Lease) and shall
automatically terminate and become null, void and of no force and effect upon
the earlier to occur of (i) the expiration or termination of this Lease by
Landlord or pursuant to any Law; (ii) the termination or surrender of Tenant's
right to possession of the Premises; (iii) the assignment of this Lease by
Tenant (to other than a Related Entity); (iv) the sublease by Tenant of more
than 50% of the rentable area of the Premises, which sublease(s) shall have
expiration dates within six months of the

                                       38
<PAGE>

Expiration Date of this Lease (to other than a Related Entity); or (v) the
failure of Tenant to timely and properly exercise its rights under this
provisions.

              ARTICLE 39 TENANT'S CONTRACTORS AND SERVICE PROVIDERS

      39.1 Tenant may, in the exercise of its commercially reasonable judgment,
enter into contracts with service providers. For example, Tenant may enter into
contracts with a caterer to service the cafeteria located within the Premises, a
security firm and/or a janitorial firm to provide services to the Premises.
Tenant shall, from time to time, give notice to Landlord of the name and address
of the contractors or the service providers and such other information as
Landlord may reasonably request. Landlord and Tenant agree that in the event
Landlord elects to retain a security firm to provide security to the common
areas of the Building, that Landlord and Tenant shall cooperate and coordinate
in the delivery of security services to the common areas of the Building and to
the Premises.

(Signature page to follow).
<PAGE>

      IN WITNESS WHEREOF, Landlord and Tenant have duly executed this Lease as
of the day and year first above written.

Signed, Sealed, and Delivered         LANDLORD:
in the Presence of:
                                      WE KNOTTER, L.L.C.
________________________              By: Winstanley Enterprises, LLC
                                          Its Manager

________________________              By: _________________________

                                          Its

                                      TENANT:

                                      ALEXION PHARMACEUTICALS, INC.
________________________

                               By: ____________________________

________________________                  Its
<PAGE>

                                   EXHIBIT A

                              [Floor Plan Omitted]
<PAGE>

SCHEME AA
350 Knotter Road, Cheshire, CT
AREA SUMMARY

Date: December 15, 1999
Project No.: 99591

==========================================
SUMMARY:
------------------------------------------
Rentable Area                      133,939
------------------------------------------
Common Area                         12,900
------------------------------------------
Usable Area                        121,039
------------------------------------------
R/U Ratio                            1.107
==========================================

================================================================================
SUMMARY:                            USF                                  RSF
Tenants                                                                USFxR/U
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
Arch Chemical                    47,036                                 52,049
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
Alexion                          74,003                                 81,890
--------------------------------------------------------------------------------

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

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

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

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

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

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

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

--------------------------------------------------------------------------------
TOTAL                           121,039                                133,939
================================================================================
<PAGE>

                                    EXHIBIT B

                              ANNUAL RENT SCHEDULE

      Annual Rent Schedule:

1.    For the first 4 months of the Term, no Fixed or Additional Rent shall be
      payable (other than utilities as may be payable under Article 11).

2.    For the fifth and sixth months of the Term, no Fixed Rent will be payable,
      but Tenant shall pay its Pro Rata Percentage of Real Estate Taxes and
      Operating Expenses. Utility expenses shall be payable in accordance with
      the provisions of Article 11.

3.    For the remainder of the initial Term and, for each Extended Term, if
      exercised, Fixed Rent will be payable at the following amounts for the
      applicable periods.

<TABLE>
<CAPTION>
                              Annual Rate                       Annual Fixed          Monthly Fixed
Period                        Per Square Foot                   Rent                  Rent
------                        ---------------                   ----                  ----
<S>                           <C>                               <C>                   <C>
Months 7-24                   $11.75                            $962,207.50           $80,183.96

Months 25-60                  $12.50                            $1,023,625.00         $85,302.08

Months 61-96                  $13.25                            $1,085,042.50         $90,420.21

Months 97 - Scheduled
Expiration Date               $14.00                            $1,146,460.00         $95,538.33

First Extended Term
The greater of                (i) $15.00 or (ii) the            (to be determined)    (to be determined)
                              fair market rental value
                              (as determined in accordance
                              with the provisions set
                              forth below)

Second Extended Term
The greater of                (i) $16.00 or (ii) the            (to be determined)    (to be determined)
                              fair market rental value
                              (as determined in accordance
                              with the provisions set
                              forth below)

Third Extended Term
The greater of                (i) $19.00 or (ii) the            (to be determined)    (to be determined)
                              fair market rental value
                              (as determined in accordance
                              with the provisions set
                              forth below)
</TABLE>

      To the extent Tenant utilizes all or any portion of the Allowance, then
the Fixed Rent amounts set forth above for the initial Term shall be increased
to include the amortized Allowance amount (including interest) and Landlord and
Tenant will execute an amendment to this Lease to reflect the increased Fixed
Rent payable by Tenant.

                                       2
<PAGE>

      Tenant's Pro-Rata Percentage is 61.14% (calculated on the basis of the
rentable square footage of the Premises at 81,890 square feet and the total
rentable area of the Building of 133,939 square feet).

      The Term Fair Market Rental Value shall mean the fair market rental of
similar buildings, housing bio-technical or bio-chemical research uses, of
similar age, size and location as the Premises within the New Haven County area
(but without regard to the value of Tenant's Property). If Landlord and Tenant
are unable to agree on such Fair Market Rental Value they shall each choose an
MAI appraiser having at least 10 years experience in appraising such similar
buildings. If the two appraisers cannot agree on a Fair Market Rental, they
shall together choose a third similarly qualified appraiser, whose appraisal of
the Fair Market Rental shall be final and binding upon Landlord and Tenant and
may be entered by either party as a final judgement in any court of competent
jurisdiction. Landlord and Tenant shall each bear the cost of their chosen
appraiser and shall share equally the cost of any third appraiser chosen. The
Fixed Rent during each such extended term shall be paid at the times and in the
manner provided in the Lease for the payment of Fixed Rent, but in an amount as
calculated as provided in this Exhibit.

                                       3
<PAGE>

                                    EXHIBIT C

                Alexion Pharmaceuticals, Inc. Chemical Inventory
                               (Subject to Change)
A

Amyl Acetate
Accuclot
Albmumin Human Essentially Fatty Acid Free
2-Aminoethylisothiouronium Bromide Hydrobromide
2-4-Dinitrophenylhydrazine
2-Chloroethanol
2-Mercaptoethanol Electrophoresis Reagent
2-Mercaptoethylamine Hydrochloride
2-mercaptoethanol molecualr biology reagent
A-Naphthyl Acetate
3-Isobutyl-1-Methylxanthine
5,5' dithio-bis(2-nitrobenzoic acid),dtnb
5-Cholomethylfluorescein Diacetate
5-sulfosalicylic acid dihyrdrate
7-amino-4-chloromethylcoumarin (cell tracker Blue CMAC)
8-chloromethyl-4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a, 4a-diaza-s-indacene
8-azaguanine(50X) Hybri-MAx gamma-irradiated
ABC Dry chemical
Acetic Acid, Glacial
acetonitrile
Acetonitrile Ace reagent
Acrylamide/Bis-Acrylamide 19 : 1 ratio
Acrylamide
actinomycin d from from streptomyces species
adenosine 5'-triphosphate disodium
a-galactosidase from escherichia coli
agarose conjugated anti-phosphotyrosine (monoclonal lgG2bk), mouse
alchohol, usp
aluminum ammonium sulfate dodecahydrate
americleasr tissue-clearing solvent
aminopterin, (50x) hybri-max gamma-irradiated
ammonium acetate, anhydrous acs reagent
ammonium chloride
ammonium persulfate
ammonium bromide, 99+%, a.c.s. reagent
ammonium sulfate grade I
apo-transferrin human
quidel assay kit - a006
ammonium sulfamate
amorphous sodium/calcium borosilicate glass
ampicillin sodium crystalline
antibody sensitized she ep erythrocytes

                                  Page 1 of 13
<PAGE>

A (cont')

anti chicken egg albumin (ovalbumin) developed in rabbit delipidized, whole
serum
antifoam a emulsion
anti-human fyn (p59 fyn) protien (whole serum), rabbit
anti-human 1 ck kinase (ct), rabbit
anti-mouse lgg (fc specific) developed in goat affinity isolated antigen
specific
antibody absorbed with human lgg
anti-phosphotyrosine (monoclonal lgG2bk), mouse
anti-rat lgg (whole molecule) developed in rabbit lgg
aptt-fsl reagent
aprotinin from bovine lung
anti-rabbit lgg-agaroso (whole molecule) developed in goat solid phase second
antibody
autoradiography enhancer

B

BCA
barbital sodium--dea schedule IV item
barium sulfate
benzamidine hydrochloride hydrate
b-galactosidase grade VIII from escherichia coli
b-glucuronidase from mollusk type h-2
blue dextran mol.wt.2,000,O0O
b-nicotinamide adenine di nucleotide phosphate reduced formtrasodium
boric acid acs reagent
boric acid sigma grade
boric acid molecular biology reagent
5-bromo-2'-deoxyuridine sigma grade
n-butane
n-butyric acid, sodium

F

Cacodylic acid sodium cryst
cacodylic acid, sodium salt hydrate 98%
calcium chloride anhydrus
carbenicillin disodium
carbon-14
carboxy-sulfrom bonded silica gel
catechol crystalline

                                  Page 2 of 13
<PAGE>

C (cont')

celestine blue
cellufine GCL-25
cell tracker orange
cellufine GCL-90
cesium chloride molecualr biology reagent
chloramphenicol cyrstalline
chloroform
chloroform ACS grade
chloroform molecular biology reagent
chloroquine disphosate crystalline
cholesterol cell culture tested
chromium-51
coagulation control level I
coagulation control level II
coagulation control level III
cobalt(II) bromide, 99%
cobalt chloride hexahydrate acs reagent
cobalt(II) bromide, 99%
collagenase p
collagenase type v
colloidal gold and colloidal silver labeled proteins, enzymes & ligand
complement component C1Q from human serum
complement component C1Q deficient serum from human plasma lyophilized
complement factor B deficient serum human
complement C2 deficient serum human
complement serum, standard human frozen
complement C5 deficient serum human
complement C5A human, recombinant
complement c8 deficient serum human
conanavalin a-sepharose 4b
concanavalin a type iv
copper(II) sulfate pentahydrate, 99.999%
cretine phosphokinase type I from rabbit muscle
gram crystal violet solution
cupric chloride hydrate
cupric sulfate pentahydrate acs reagent
cycloheximide from streptomyces griseus
crystal ponceau 6R
cytidine, 99%

                                  Page 3 of 13
<PAGE>

D

deae-sephacel anion exchanger
dehydrated alcohol usp
deoxyribonuclease I type II-s from bovine pancreas
deoxycytidine-5'-Triphosphate, [alpha-32P]
deoxycholic acid sodium
dextran mol. wt. 500,000
dextrose, anyhdrous
dextrin type i
dcomts
disodium phosphate
diethyl pyrocarbonate
diluent kit for pkh26-gl or pkh95
dimethyl pimelmidate dihydrochloride
dimethyl sulfoxide acs regent
n,n dimethylformamide acs reagent
dl-dithiottreitol electrophoresis reagent
dithiothreitol (DTT)
5,5-dithio-bis (2-nitrobenzoic acid)
dot-e 7891

E

ecl western blotting detec.reagents (contains 2X250ml) formula:N/A
ecolume
embedding medium, infiltration medium
enolase from bakers yeast
endotheial cell growth supplement from bovine pituitary glands
en3hance(tm) spray
enterokinase from porcine intestine
environmentally hazardous substances, colid, n.o.s., cobalt (II) bromide
eosin
(-)-epinephrine (+)-bitartrate
ethidium bromide
enhance spray for surface autoradiography
ethanol
ether, 99.9%, HPLC Grade, Inhibitor-free
ethyl alcohol 200 proof usp
ethidium bromide tablets 100mg per tablet molecular biology reagent
ethylenediaminetetraacetic acid disodium dihydrate
ethylenediaminetetraacetic acid tetrasodium
ethyl alcohol 200 proof usp
ethylene glycol monomethyl ether
evans blue

                                  Page 4 of 13
<PAGE>

F

fixative
"44" flux cored solder
factor IX deficient plasma
fast green fcf
fast red violet lb salt
ferrous sulfate heptahydrate 99+%
fluorescein
folin & ciocalteu's phenol reagent
formaldeyde
formalin solution, neutral buffered
formamide
forskolin from coleus forskohl II

G

geneticin disulfate
glutaraldehyde grade I
glutaraldehyde grade II
glutaric dialdehyde, 50wt, % solution in water
glutathione oxidized form free acid sigmaultra
glycerol acs reagent
glycerol, molecular biology reagent
glyoxal, 40wt. %solution in water
goat anti-human igg (fc specific) agarose, affinity isolated anitbody
goat anti-human igm (mu chain specific) isolated antibody, antibody absorbed
          with mouse and rat igg
guanidine thiocyanate
guanidine thiocyante molecular biology

H

harris hematoxylin
l-cysteine hydrochloride anhydrous
hat media supplement (50x) hybri-max gamma irradiated
hazorb-universal
hematoxylin
heptanoic acid
heparin sodium cell culture tested
heparin sodium grade I-A from porcine intestinal mucosa
ketamine hydrochloride
hexadecyltrimethylammonium bromide
hexadecyltrimethylammonium bromide flukabrand

                                  Page 5 of 13
<PAGE>

H (cont')

hexadimethrine bromide
hexanes
histamine DI-hcl
hoechst 33258 (bisbenzimide)
human serum gamma-globulin free
hydrochloric acid
hydrochloric acid solution 1.on
hydrogen-3
hydrogen peroxide 3% (W/W) solution
hydrogen peroxide 30% (W/W) solution
hydroxylamine hacl grade I
hygromycin B
ethanolamine free base
hygromycin B hydrochloride from streptomyces hygroscopicus cell culture tested

I

iminodiacetic acid-epoxy activated sepharose 6B fast flow
iminodiacetic acid free acid
imidazole apporx. 99%
injection solution
indomethcin crystalline
insulin chain A. oxidized from bovine insulin ammonium
insulin chain A. oxidized from bovine insulin free acid
insulin from bovine pancreas
insulin-transferrin sodium selenite media supplement gamma-irradiated cell
culture tested\
invertase grade VII
invitrogen
iodine-125
iodoacetamjide crystalline
iodo (1-14c) acetamide / monoiodacetamide
isobutane
isopropanol molecular biology reagent
isopropyl b-d-thiagalactopyranoside
isopropyl alcohol
isopropyl alcohol and water

K

kanamycin monosulfate from streptomyces

                                  Page 6 of 13
<PAGE>

L

l-isokeucine
lactic dehydrogenase kit
lauryl sulfate sodium
lectin from bandieraea simplicifolia bs-l isolectin B4
lectin from canavalia ensiformis typeiv-s gamma - irradiated
lectin from canavalia ensiformis typeiv-s sterile filtered cell culture tested
lectin from phaseolus vulgaris leucoagglutinin pha-I
lectin from phaseolus vulgaris leucoagglutinin pha-I cell culture tested
lectin from phytolacca
lectin from phytolacca americana sterile filtered
leupeptin hemisulfate from microbial source
l-leucine sigma grade
linoleic acid free acid approx. 99%
lipopolysaccharide chromatographically purified from salmonella abortus equi
phenolic extract
lipipolysaccharide from E.coli 0111:84 cell culture tested
lipopolysaccharide from escherichia coli serotype 0127:B8 phenol extract
lithium acetate dihydrate
lithium chloride anhydrous commercial grade
lithium sulfate
l-tryptophan sigam grade
l-lysine monohydrochloride, 99+%
lysozyme egg white for sds gel electrophoresis
lysozyme grade I from chicken egg white

M

magnesium chloride, 6-hydrate, crystal
majestic staunless stell protective polish (aerosol)
manganese chloride tetrahydrate
menadione sodium bosulfate cell culture tested
mallinckrodt
matrex cellufine sulfate
magnesium sulfate, 7-hydrate
matrex cellufine GCL-25
tmb substratre soluition
maleic anhydride
martius yellow sodium monohydrate
2-mercaptoethanol cell culture tested
2-mercaptoethanol
tmb substrate solution
methanol absolute

                                  Page 7 of 13
<PAGE>

methanol spectrophotometric grade
methyl isobutyl ketone
methyl sulfoxide, anyhydrous, 99+%
methylene blue trihydrate
2-methylnaphthalene (BETA)
N,N-Methylene-Bix-Acrylamide
mineral oil light white oil
mineral spirits regular
mitomycin c from streptomyces caespitosus
molybdic acid sodium dihydrate
mops free acid
monoclonal anti-alpha-smooth muscle actin, clone 1A4
myelin basic protein from bovine brain
mycophenolic acid from penicillium brevi-compactum

N

2-naphthalenesulfonic acid, sodium salt, tech., 90%
naphthol as-bi butyrate
naphthol as-d chloroacetate
nnaphthol as phospate sodium
naphthol as-mx phosphate free acid
naphthol blue black
naphthol green b.1% in 1% acetic acid
neomycin sulfate
n-1-naphthylethylenediamine di hcl culk
na-p-tosyl-l-lysine chloromethyl ketone hydrochloride
n-butanol
neuraminidase type x from clostridium perfringes
neuraminidase from clostridium perfringes aseptically filled
neutral red cell culture tested
n-heptane
nickel chloride hexahydrate
nitrate reductase (nad(p)h) from aspergillus species
nitric acid, fuming, 90%
nitro blue tetrazolium 10mg tablets
n-lauroylsarcosine free acid
n-lauroylsarcosine sodium
nbt(nitrotetrazolium blue chloride)
n,n dimethylformaamide
n-lauroylsarcosine sodium
n-octyl b-d-glucopyranoside
n-tosyl-l-phenylanalnine chlromethyl ketone
nonidet p-40
nitro blue tetrazollum grade III crystalline
nutridoma sp

                                  Page 8 of 13
<PAGE>

O

o-dianisidine dihydrochloride 10 mg tablets
o-dianisidine dihydrochloride
oleic acid free acid approx. 99%
orange G sodium
owren's buffer
oxalic acid

P

potassium sulfate acs reagent granular
palmitic acid free acid sigma grade
pararosaniline chloride
pararosaniline base
penicillin-g sodium
penicillin-streptomycin solution
phenylmethylsulfonyl fluoride
polyvinylpyrrolidone molecular biology reagent
polyethyleneimine bonded silica gel
o-phenylenediamine tablets
o-phenylenediamine dihydrochloride
o-phenylenediamine free base
povidone solution, u.s.p.
paraformaldehyde
pentanesulfonate, sodium salt
pepstatin A
periodic acid (hydrate)
phenol/chloroform
phenol molecfular biology reagent
phenylhydrazine hydrochloride
p-phenylenediamine free base
phenylhydrazine hydrochloride
phorbol 12-myristate 13-acetate
phosphate-citrate buffer with sodium perborate capsules
phosphatase alkaline type XXIV from human placenta
phosphoric acid
phosphoric acid 85% certified
phosphorus-32
phosphotungstic acid free acid cyrstalline
pkh26 linker for red fluorescent cell labeling
pkh26 red fluorescent cell linker kit for general membrane labeling
poly(ethylene glycol), average m.w. 2000
poly-l-lysine hydrobromide mol wt greater than 300000
poly-l-lysine hydrobromide mol wt 70000-150000

                                  Page 9 of 13
<PAGE>

P (cont')

polyethlenimine, high molecular weight, 50wt.% solution in water
ponceau s solution 0.1% ponceau s (m/v)
ponceau s solution, 2% ponceau s (w/v)
ponceau S sodium practical grade
potassium chloride
potassium ferricyanide acs reagent
potassium ferrocyanide trihydrate acs reagent
protein g-sepharose 4 fast flow
potassium phosphate, dibasic
potassium phosphate, monobasic
promega
pronectin f
propane
propidium iodine
prostaglandin e1
protein a sepharose 4 fast flow
proteinase k from tritrachium album molecular biolgy reagent

R

rat igg technical grade from serum
reagent kit for sequencing w/sequenase(R) and 7 deaza-dgtp
restriction endoclease dsa i
restriction endoclease swa i
ribonuclease t1 from aspergillus drze, lypholized
ribonuclease a type iii-a from bovine pancreas
ribonuclease A typei-as from bovine pancreas
rifampicin cyrstalline
roccal (r) ii-10%
rpmi-1640 medium with 1-glutamine w/o phenol red or sodium bicarbonate
rpn 2106
rpn226

S

s-(2-aminoethyl) isothiouronium bromide hydrobromide, 99%
sera. complement human
sera human frozen liquid
sigmacote
sigma enzyme control 2-e

                                 Page 10 of 13
<PAGE>

S (cont')

silane coated microscopes
silicone rubber compound
silica
sliver stain plus kit
silver nitrate
silver nitrate, 99.998%
silver nitrate cyrstalline
silver stain "daiichi"
silver, wire, 0.1 mm diam., 99.9%
2d silver stain "daiichi" II
sodium acetate molecular biology reagent
sodium actate trihydrate acs reagent
sodium azide
sodium borate decahydrate acs reagent
sodium cyanoborohydride
sodium carbonate anydrous acs reagent
soidum chloride sigma grade
sodium chloride
soidum chloride sigma grade
sodium fluoride crystalline
sodium hydroxide pellets acs reagent
sodium iodate
sodium iodine anyhydrous
sodium m-periodate acs reagent
sodium nitrate
sodium nitrite crystalline
sodium nitroprusside dihydrate
sodium orthovanadate
sodium phosphate dibasic, anydrous acs
sodium phosphate dibasic heptahydrate acs reagent
sodium phosphate, dibasic, 12-hydrate
sodium pyrophosphate decahydrate acs reagent
sodium sulfute anhydrous
sodium tetrathionate, dihydrate
sodium thiosulfate pentahydrate
sodium thiocyanate
streptomycin sulfate
sulfanilmaide
sulfo-nhs-biotin
sulphur-35
s/p brand xylene
staphylococcal enterotoxin b from staphylococcus aureus

                                 Page 11 of 13
<PAGE>

T

taurine synthetic
tetracycline hydrochloride cyrstalline
tetramethylammonium chloride, 97%
2,6,10,14-tetramwthylpentadaecane
3,3',5,5'-tetramethylbenzidine free base
theophyilline crystalline anhydrous
thiamine hydrochloride
thrombin from human plasma
thrombin from human plasma
thymide cell culture tested
thymidine, [methyl-3H]
thymol crystalline
toluene
(2S,3S)-trans-epoxysuccinyl-l-leucylamido-3-methylbutane
apo-transferrin human
tributyl phosphate, 99+%
trichloroacetic acid crystalline
triethlyamine
triethanolamine free base
trifluoracetic acid
trifluoracetic acid protein sequencing
2,3,5-triphenyltetrazolium chloride
trypsin
trypsin inhibitor type II-s
trypsin1:250 from porcine pancreas gamma-irradiated cell culture tested
tungstic acid sodium dihydrate
1,1,2-trichloro-1,2,2-trifluoroethane
triton X-114
triton X-114, reduced
tris hydrochloride
trizma base reagent grade
trizma hydrochloride reagent grade
trizma base reagent grade
trizma hydrochloride reagent grade
trizma hydrochloride sigmaultra
tunicamyucin from a streptomyces species
tween 80

U

urea
urea cell culture tested
urease type iii from jack beans

                                 Page 12 of 13
<PAGE>

V

vesphene II se

W

wright giemsa fucillo

X

xanthine sodium cell culture tested
xiazine hydrochloride
xylene
xylene cyanole ff, dye content: approx 75%

z

zinc chloride
zinc chloride, 99.999%
zinc sulfate heptahydrate
zymosan a from saccharomyces cerevisiae

                                 Page 13 of 13
<PAGE>

                                    EXHIBIT D
                                   WORK LETTER

      This Exhibit is attached to and made a part of the Lease and is entered
into as of the __ day of ________________, 2000 by and between WE KNOTTER,
L.L.C., a Delaware limited liability company ("Landlord") and ALEXION
PHARMACEUTICALS, INC. ("Tenant") for space in the Building located at 350
Knotter Drive, Cheshire, Connecticut.

1.    Alterations and Allowance.

      A.    Tenant, following the delivery of the Premises by Landlord and the
            full and final execution and delivery of this Lease and all prepaid
            rental and security deposits required hereunder, shall have the
            right to perform alterations and improvements in the Premises (the
            "Initial Alterations"). Notwithstanding the foregoing, Tenant and
            its contractors shall not have the right to perform Initial
            Alterations in the Premises unless and until Tenant has complied
            with all of the terms and conditions of Article 9 of this Lease,
            including, without limitation, approval by Landlord of the final
            plans for the Initial Alterations. Tenant shall be responsible for
            obtaining all necessary permits and approvals in connection with the
            performance and completion of the Initial Alterations and for all
            elements of the design of Tenant's plans (including, without
            limitation, compliance with law, functionality of design, the
            structural integrity of the design, the configuration of the
            Premises and the placement of Tenant's furniture, appliances and
            equipment), and Landlord's approval of Tenant's plans shall in no
            event relieve Tenant of the responsibility for such design. In the
            event Tenant does not use Landlord's electrical, mechanical and
            roofing consultants then, Landlord's engineer and/contractor, at
            Tenant's expense, shall review and approve the plans and
            specifications as well as the work performed by Tenant's consultants
            and contractors.

      B.    Provided Tenant is not in default, Landlord agrees to contribute an
            amount not to exceed the product of $30 times the rentable square
            footage of the Premises, or $2,456,700.00, (such amount,
            "Allowance") toward the cost of performing the Initial Alterations
            in preparation of Tenant's occupancy of the Premises. Tenant is not
            obligated to accept or utilize the Allowance. The Allowance shall be
            repaid with interest at the rate of 11% per annum at the times and
            in the manner set forth in the Lease. The Allowance may only be used
            for the cost of preparing design and construction documents and
            mechanical and electrical plans for the Initial Alterations and for
            hard costs in connection with the Initial Alterations. The
            Allowance, less a 7.5% retainage (which retainage shall be payable
            as part of the final draw), shall be paid to Tenant or, at
            Landlord's option, to the order of the general contractor that
            performs the Initial Alterations, in periodic disbursements within
            thirty (30) days after receipt of the following documentation: (i)
            an application for payment and sworn statement of contractor
            substantially in the form if AIA Document G-702 covering all work
            for which disbursement is to be made to a date specified therein;
            (ii) a certification from an AIA architect substantially in the form
            of the Architect's Certificate for Payment which is located on AIA
            Document G-702, Application and Certificate of Payment; (iii)
            Contractor's, subcontractor's and material supplier's waivers and/or
            subordinations of liens and certificates of payment which shall
            cover all Initial Alterations for which disbursement is being
            requested and all other statements and forms required for compliance
            with the mechanics' lien laws of the State of Connecticut, together
            with all such invoices, contracts, or other supporting data as
            Landlord or Landlord's Mortgagee may reasonably require; (iv) a cost
            breakdown for each trade or subcontractor performing the Initial
            Alterations; (v) plans and specifications for the Initial
            Alterations, together with a certificate from an AIA
<PAGE>

            architect that such plans and specifications comply in all material
            respects with all laws affecting the Building, Property and
            Premises; (vi) copies of all construction contracts for the Initial
            Alterations, together with copies of all change orders, if any; and
            (vii) a request to disburse from Tenant containing an approval by
            Tenant of the work done and a good faith estimate of the cost to
            complete the Initial Alterations. Upon completion of the Initial
            Alterations, and prior to final disbursement of the Allowance,
            Tenant shall furnish Landlord with: (1) general contractor and
            architect's completion affidavits, (2) full and final waivers and/or
            subordinations of lien and certificates of full payment, (3)
            receipted bills covering all labor and materials expended and used,
            (4) as-built plans of the Initial Alterations, (5) the certification
            of Tenant and its architect that the Initial Alterations have been
            installed in a good and workmanlike manner in accordance with the
            approved plans, and in accordance with applicable laws, codes and
            ordinances, and (6) a copy of the permanent or temporary certificate
            of occupancy for the Premises. In no event shall Landlord be
            required to disburse the Allowance more than one time per month. If
            the estimated cost of the Initial Alterations exceed the Allowance,
            Tenant shall be entitled to the Allowance in accordance with the
            terms hereof, but each individual disbursement of the Allowance
            shall be disbursed in the proportion that the Allowance bears to the
            total cost for the Initial Alterations, less the 7.5% retainage
            referenced above. Notwithstanding anything herein to the contrary,
            Landlord shall not be obligated to disburse any portion of the
            Allowance during the continuance of an uncured default under the
            Lease, and Landlord's obligation to disburse shall only resume when
            and if such default is cured.

      C.    In no event shall the Allowance be used for the purchase of moveable
            equipment, furniture or other items of personal property of Tenant.
            In the event Tenant does not properly submit a request for payment
            of the entire Allowance to Landlord in accordance with the
            provisions of this Exhibit D on or before the expiration of the 6
            month of the Lease Term, any unused amount shall accrue to the sole
            benefit of Landlord, it being understood that Tenant shall not be
            entitled to any credit, abatement or other concession in connection
            therewith. Tenant shall be responsible for all applicable state
            sales or use taxes, if any, payable in connection with the Initial
            Alterations and/or Allowance.

      D.    Except with respect to the Substantial Completion of Landlord's
            Work, to be performed pursuant to Exhibit G, Tenant agrees to accept
            the Premises in its "as-is" condition and configuration, it being
            agreed that Landlord shall not be required to perform any work other
            than Landlord's Work or, except as provided above with respect to
            the Allowance, incur any costs in connection with the construction
            or demolition of any improvements in the Premises.

      E.    This Exhibit shall not be deemed applicable to any additional space
            added to the original Premises at any time or from time to time,
            whether by any options under the Lease or otherwise, or to any
            portion of the original Premises or any additions to the Premises in
            the event of a renewal or extension of the original Term of this
            Lease, whether by any options under the Lease or otherwise, unless
            expressly so provided in the Lease or any amendment or supplement to
            the Lease.

                                       2
<PAGE>

WITNESS/ATTEST:                         LANDLORD:

                                        WE KNOTTER, L.L.C.
                                        Delaware limited liability company

                                        By: Winstanley Enterprises, LLC
                                        its general partner

______________________________          By:    ______________________________

Name (print):_________________          Name:  ______________________________

______________________________          Title: ______________________________

Name (print):_________________

WITNESS/ATTEST:                         TENANT:

                                        ALEXION PHARMACEUTICALS, INC.

______________________________          By:    ______________________________

Name (print):_________________          Name:  ______________________________

______________________________          Title: ______________________________

Name (print):_________________]

                                       3
<PAGE>

                                    EXHIBIT E

                                 LANDLORD'S WORK

      In order to induce Tenant to enter into the Lease to which this Exhibit is
attached and in consideration of the mutual covenants hereinafter contained,
Landlord and Tenant hereby agree as follows:

      1. LANDLORD'S WORK.

      Reference herein to "Landlord's Work" shall mean the following work to be
done by Landlord at the Building: (i) installation of a new roof; (ii) repaying
and restriping of the existing parking lot, (iii) repair, or if Landlord
determines it to be necessary, replacement of the existing heating, ventilation
and air conditioning units servicing the Premises and installation of energy
management systems; (iv) construction of a common entrance to the Building in
the area shown on the Plan; (v) installation of demising walls between the area
of the Premises and the remaining area of the Building in locations shown on the
Plan; (vi) separation of utilities to permit, to the extent feasible, separate
metering or submetering; (vii) installation or upgrade of fire alarm system
improvements to meet current NFPA 101 - Code for Safety to Life Standards (the
"Life Safety Code"); (viii) tenant signage (as approved by Landlord and all
applicable Governmental Authorities); (ix) clean all supply ductwork; (x)
provide for separate lab waste systems between tenants; (xi) develop a separate
potable/non-potable water system including all related tie-ins to deliver
sufficient potable water for tenant's use at its eyewash and safety shower
systems and to the lavoratories and kitchens located in the Premises; (xii)
emergency lighting upgrades to meet current Life Safety Code; and (xiii) in the
chemical lab areas where Arch is removing Halon Sprinkler Systems, the hook-up
or installation of a wet sprinkler system.

      2. PERFORMANCE OF LANDLORD'S WORK.

      Landlord shall use commercially reasonable efforts to complete items (iii)
through (xiii) of Landlord's Work during the Arch Move-Out Period and items (i)
and (ii) within 6 months thereafter. Landlord shall also use commercially
reasonable efforts to promptly repair existing roof leaks where they exist in
non-warehouse areas of the Premises.

      3. COMPLETION OF LANDLORD'S WORK.

      Landlord's Work shall be deemed substantially complete when Landlord's
construction manager certifies the same has been substantially completed,
notwithstanding the fact that minor details of construction, mechanical
adjustments or decorations which do not materially interfere with Tenant's use
and enjoyment of the Premises remain to be performed (items normally referred to
as "punch list" items). All punch list items shall be agreed upon by Landlord
and Tenant and shall be promptly completed by Landlord.

<PAGE>

                                    EXHIBIT F

                         NOTICE OF COMMENCEMENT OF LEASE

To:     ___________________________        Date:     __________________________
        ___________________________
        ___________________________

Re:    Lease dated ___________, 20__, between__________________________________,
       Landlord, and ________________________________________, Tenant located at
       ______________________________________________________.

Gentlemen:

      In accordance with the subject Lease, we wish to advise and/or confirm as
follows:

      1. That the Tenant has possession of the Premises and acknowledges that
under the provisions of the Lease the Term of said Lease shall commence (or has
commenced) as of __________ for a Term of __________ ending on___________.

      2. That in accordance with the Lease, Tenant's obligation to pay Fixed
Rent commenced or shall commence to accrue on ________________________.

      3. Rent is due and payable in advance on the first day of each and every
month during the term of said Lease. Tenant's rent check should be made payable
to ___________________________________ at _________________________________.

      4. The Landlord has substantially completed the Landlord's Work, in
accordance with the Lease, except for punch1ist items and _________________.

ACCEPTED AND AGREED

LANDLORD:                               TENANT:

__________________________              ___________________________

By:_______________________              By:________________________

<PAGE>

--------------------------------------------------------------------------------
CHESHIRE ZONING BY-LAWS - ARTICLE III DISTRICT REGULATIONS                Page 1
Munilaw
--------------------------------------------------------------------------------

                                                                       EXHIBIT G

CHESHIRE ZONING BY-LAWS - ARTICLE III DISTRICT REGULATIONS
NEW HAVEN COUNTY
TOWN OF CHESHIRE

                                  ARTICLE III

                              DISTRICT REGULATIONS

SECTION 30 Permitted Uses. "Schedule A, Permitted Uses", is hereby declared to
be part of these Regulations. Land and structures in a district shall be used
only for one or more of the uses which are specified in Schedule A as being
permitted in the district. Uses listed in Schedule A are permitted or prohibited
in accordance with the following procedures:

"Y"   means a use permitted as a matter of right.

"P"   means a use permitted subject to obtaining a Special Permit from the
      Planning and Zoning Commission as provided in Section 40.

"S"   means a use permitted subject to the administrative Site Plan approval by
      the Planning and Zoning Commission as provided in Section 41.

"N"   means a use not permitted.

Where two or more permitted uses occupy one lot, the minimum area requirement
for that lot shall be calculated by separating the requirements for a
residential unit or units from other permitted uses on that lot, as detailed in
Schedule A. (1) When located on the same lot as a dwelling unit or units and
when conducted by a resident of the property, certain uses are considered
accessory to the residential use, and the minimum lot size shall be determined
only by the residential use(s), as specified by Section 32, Schedule B, or the
lot

(1) Amendment effective December 23, 1975.
(1) Amendment effective October 30, 1981.

<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
 ..    Dwellings containing one dwelling unit and not more than two        Y      Y      Y      Y       N     N     N     N     N
      such dwellings per lot provided all requirements of these
      Regulations shall be met for each dwelling unit as though each
      were on an individual lot.(l)
lA.   Dwellings containing one (1) dwelling unit and not                  P      P      P      P       N     N     N     N     N
      more than two (2) such dwellings per rear lot (as
      regulated by Section 5.5 of the Subdivision
      Regulations) providing all requirements of the
      regulations shall be met for each dwelling unit as
      though each were on an individual rear lot.(6)
---------------------------------------------------------------------------------------------------------------------------------
      Dwellings containing one dwelling unit, and not                     Y      Y      Y      Y       Y     Y     Y     N     N
      more than one such dwelling per lot, occupied by a
      person, together with his family, who is the
      owner, corporate officer, manager, caretaker, or
      janitor of a permitted commercial use on the same
      lot.(2)
---------------------------------------------------------------------------------------------------------------------------------
A.    Dwellings containing one or two dwelling units and not              N      N      N      N       P     P     P     N     N
      more than two dwellings per lot may be permitted in
      commercial zones subject to the following conditions:
      1.    That the areas to be used for residential purposes
            shall meet all the requirements of a residence in
            an R-20 zone and each dwelling unit shall require
            20,000 square feet exclusive from any other use or
            dwelling unit on the lot.(3)
---------------------------------------------------------------------------------------------------------------------------------
     Dwellings containing two dwelling units and not more                 P      P      P      P       N     N     N     N     N
     than two such dwellings per lot provided all
     requirements of these Regulations shall be met for each
     dwelling as though it were on an individual lot and each
     dwelling unit meets the applicable minimum lot area
     requirements.(5)
---------------------------------------------------------------------------------------------------------------------------------
3,4   Amendment effective December 23, 1975
      Amendment effective October 30, 1981
      Amendment effective August 27, 1984
      Amendment effective December 4, 1992
      Amendment effective March 27, 1998.
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                     (30-2)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
5.(1) One additional dwelling to be used as an in-law,                    P      P      P      P       P     P     P     P     P
      apartment, including kitchen facilities, may be located
      in the dwelling even if the size of the lot is not large
      enough to fulfill the minimum lot area requirements for
      an additional dwelling unit, and shall be subject to the
      following conditions:

      a.    That the entire dwelling is only to be occupied by
            family members (related by blood, marriage, or
            adoption), and is not to be rented or used for
            income purposes.
      b.    That tile in-law apartment shall be directly
            attached to the existing dwelling or attached to
            the dwelling via an enclosed structure. In
            addition, the in-law apartment shall not exceed a
            maximum floor area of 750 square feet.
      c.    That the in-law apartment shall be accessible to
            the main dwelling unit.
      d.    That the in-law apartment shall utilize the
            dwelling's existing driveway and utility meters.
      e.    That wherever possible the entrance to the in-law
            apartment shall be located to the side or rear of
            the existing dwelling and/or the proposed
            addition.
      f.    That the Special Permit is temporary in that it
            shall expire five (5) years after publication of
            the legal notice of the approval, or at the time
            of sale or transfer of the property, whichever
            comes first. The Planning and Zoning Commission
            may, at the request of the property owner, extend
            the permit for any number of periods, each not
            longer than five (5) years. This may be done by
            providing the Commission with a notarized
            statement verifying that the use of the in-law
            apartment complies with the above requirements.(5)
      g.    If the Special Permit expires, the property
            owner shall at his or her own expense, remove the
            kitchen facilities within sixty (60) days of the
            expiration of the Special Permit.(2)
---------------------------------------------------------------------------------------------------------------------------------
5A.   Plannned Residential Developments provided such                     P      P      P      P       N     N     N     N     N
      development is served by a public sanitary
      sewerage system and a public water supply system
      or a state-approved community water supply system,
      and subject to the provisions of Section 43.
5B.   Planned Residential Developments designed                           N      N      N      P       N     N     N     N     N
      exclusively for occupancy by elderly persons
      provided such development is served by a public
      sanitary sewerage system and a public water supply
      system and subject to the provisions of Section
      43.
---------------------------------------------------------------------------------------------------------------------------------
7.    Planned Residential Developments provided such                      P      P      N      N       N     N     N     N     N
      development is served by a public water supply
      system or a state-approved community water supply
      system and subject to the provisions of Section
      43.
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>
(1)   Original Para. 5 Deleted 4/29/76.
(2)   Amendment 9/26/80
(3,4) Amendments 7/1/83
(5)   Amendments 12/22/89 & 10/27/95

                                     (30-3)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
Trailers, motor homes, or mobile homes on the same lot                    P      P      P      P       P     P     P     P     P
with a dwelling containing one dwelling unit and subject
to the following conditions:

a.    There shall be no more than one trailer, motor
      home, or mobile home per lot.
b.    If the trailer, motor home or mobile home is to be
      occupied, its sanitary facilities shall have the
      approval of the Town Health Officer, and it shall
      be occupied by only one family, at least one of
      whom shall be either the owner of the lot or
      related by blood, marriage, or 1egal adoption to a
      member of the family occupying the dwelling unit.
      Such dwelling unit may be one for which a building
      permit has been issued.
c.    The trailer, motor home, or mobile home shall be
      located so as not to be generally visible from the
      street and the surrounding property.
d.    Any approval shall be limited to a period of one
      year and not renewable.
---------------------------------------------------------------------------------------------------------------------------------
Camp trailers, motor homes, boats(1) and pickup coaches,                  Y      Y      Y      Y       Y     Y     Y     Y     Y
unoccupied, not more that 23 feet in length and subject
to the following conditions:

a.    There shall be no permanent connections to utility
      service including electrical, heat, water,
      sanitary service and the like.
b.    Storage shall be to the rear of the dwelling or
      other major building, in a neat and orderly manner
      generally not visible from the street and where
      collapsible, in a collapsed state or shall be
      stored in a garage.

c.    Storage shall be limited to camp trailers, motor homes,
      boats and pickup coaches in a residential zone, but no
      more than two of the above listed items shall be stored
      per dwelling unit. In addition, such vehicles shall be
      registered in the name of and be the legal property of
      an occupant of the dwelling unit.

(1)   Amendment effective January 26, 1979.
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
10A.  A business or professional office when conducted on the             Y      Y      Y      Y       Y     Y     Y     Y     Y
      premises entirely by mail and/or telephone and when
      there is no pedestrian, automobile or other vehicular
      traffic necessary for its conduct with the exception of
      normal residential traffic activity by the residents,
      provided the use meets all the requirements as follows:

      a.    No persons other than family members residing on
            the premises, shall be engaged in the conduct of
            the office or enterprise
      b.    The office or enterprise shall not impair the
            residential character of the premises and
            neighborhood, and shall have no outside storage
            or display windows, nor shall there be any
            evidence of the operation outside the dwelling
            unit.
      c.    The floor area used for the conduct of the office
            or enterprise shall not exceed 25 per cent of the
            floor area of the dwelling unit.
      d.    The use shall not create interference with radio
            and television reception in the vicinity.
      e.    No industrial manufacturing or processing
            equipment of any type shall be allowed.(l)

(1)   Amendment effective May 27, 1976

---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                     (30-5)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
lOB.  A professional or business office or customary home                 S      S      S      S       Y     Y     Y     Y     Y
      enterprise excluding data processing and the like, in a
      dwelling unit and not in an accessory building and
      subject to the following conditions:

      a.    The person or persons conducting the office or
            enterprise shall reside in the dwelling unit, and
            there shall be no more than two non-resident
            persons engaged in the conduct of the office or
            enterprise.
      b.    The office or enterprise shall not impair the
            residential character of the premises and there
            shall be no evidence of the operation outside the
            dwelling unit except permitted signs. The use
            shall be completely enclosed in the building and
            shall have no outside storage or display windows.
      c.    The floor area used for the conduct of the office
            or enterprise shall not exceed 25 per cent of the
            finished space area of the dwelling unit.
      d.    The use shall not create interference with radio
            and television reception in the vicinity.(1)
---------------------------------------------------------------------------------------------------------------------------------
11.   The letting of rooms and/or furnishing of board in a                P      P      P      P       P     P     P     P     P
      dwelling unit to a total of not more than six persons,
      subject to the following conditions:

      a.    The person or persons letting the rooms shall
            reside in the dwelling unit.
      b.    The letting of rooms shall not include the
            provision of cooking facilities for such rooms but
            may include sharing of the cooking facilities of
            the dwelling unit.
      c.    No accessory building shall be used for letting of
            rooms or furnishing of board.
      d.    Such use shall not be combined with a commercial
            or industrial use on a lot except as provided in
            paragraph 2 of this section.

(1)   Amendment effective May 27, 1976
(2)   Amended effective January 29, 1988
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                     (30-6)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
12.   Housing subject to state and local provisions for                   Y      Y      Y      Y       Y     Y     Y     Y     Y
      migrant (temporary) farm labor, on the farm where they
      are primarily employed.
---------------------------------------------------------------------------------------------------------------------------------
13.   Farms, truck gardens, nurseries, forestry and the                   Y      Y      Y      Y       Y     Y     Y     Y     Y
      keeping of livestock and poultry except commercial
      raising of fur-bearing animals and garbage-fed swine,
      provided that no livestock or poultry, except household
      pets, shall be kept on any lot of less than 3 acres in
      area, and any building used for housing livestock and
      poultry or the storage of fertilizer or manure shall be
      located not less than 100 feet from any property or
      street line.
---------------------------------------------------------------------------------------------------------------------------------
14A.  Child day care centers and nursery schools which offer              N      N      N      P       P     P     P     P     P
      or provide a program of supplementary care to more than
      twelve related or unrelated children outside their own
      homes on a regular basis for a part of the twenty-four
      hours in one or more days in the week, provided the
      facility meets all statutes and regulations of the State
      of Connecticut for licensing of child day care centers.
14B.(3) Group day care homes which offer or provide a program             P      P      P      P       P     P     P     P     P
      of supplementary care to not less than seven nor more
      than twelve related or unrelated children on a regular
      basis for a part of the twenty-four hours in one or more
      days of the week, provided the facility meets all
      statutes and regulations of the State of Connecticut
      for licensing of group day care homes.(4)
---------------------------------------------------------------------------------------------------------------------------------
15.   Temporary stands for the display and sale of farm and               Y      Y      Y      Y       Y     Y     Y     Y     Y
      truck garden and forestry produce grown exclusively on
      the premises provided there is only one such stand on
      the premises and that such stand does not exceed 100
      square feet in area.
---------------------------------------------------------------------------------------------------------------------------------
16.   Stands for the display and sale of farm and truck garden            S      S      S      S       S     S     S     S     S
      and forestry produce, of which a major portion thereof was
      raised or produced on that bona fide farm, provided it
      is on an active farm and there is only one such stand on
      that farm.(1) Related agricultural products may be sold
      provided the sale of such products is secondary to the
      operation of the business.(2)
---------------------------------------------------------------------------------------------------------------------------------
(1)   Amendment effective 5/1/75.
(2)   Amendment effective 5/27/76.
(3)   Amendment effective 5/26/89.
(4)   Amendment effective 2/7/97.
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                     (30-7)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
17.   Buildings and facilities used primarily for the                     P      P      P      P       P     P     P     P     P
      following uses: Churches and places of worship; parish
      halls, schools, colleges, universities, museums; general
      hospitals (excluding correctional institutions and
      hospitals for the insane); cemeteries, educational,
      religious, philanthropic, scientific, literary,
      historical, and charitable institutions, agricultural and
      horticultural societies, is such uses are conducted by a
      non-profit organization and not as a business or for
      profit, provided that accessory use of such buildings
      and facilities for profit or not for profit shall be
      allowed if such use is in connection with a federally,
      State or municipally funded program for the elderly
      intended to promote the public health, welfare, safety
      or education.(1)
---------------------------------------------------------------------------------------------------------------------------------
18A.  Public Service Corporation buildings and facilities, all            P      P      P      P       P     P     P     Y     Y
      with no outside service yard or outside storage or
      supplies.(2)

18B.  Public Service Corporation buildings and facilities with            N      N      N      N       N     N     N     Y     Y
      outside service yard or outside storage supplies.(3)

18C.  Public Service Corporation buildings and facilities not             P      P      P      P       S     S     S     S     S
      exceeding 100 square feet above ground level in area or
      10 feet in height:

      a.    The facility shall be located on a lot or
            casement of not less than 400 sq. ft.
      b.    Minimum setback from street line shall be 10 feet.
      c.    Minimum setback from side line and rear line shall
            be 5 feet.
      d.    Sufficient landscaping and screening shall be
            provided to insure that the facility is in
            harmony with the zone and the surrounding
            neighborhood.
      e.    All utility wires from adjacent poles to the
            facility shall be underground.(4)
---------------------------------------------------------------------------------------------------------------------------------
19.   Municipal Buildings and Uses of the Town of Cheshire and            P      P      P      P       P     P     P     P     P
      other governmental uses.(5)
---------------------------------------------------------------------------------------------------------------------------------
(1)   Amendment effective October 30, 1975.
(2)   Amendment effective September 17, 1979.
(3)   Amendment effective September 17, 1979.
(4)   Amendment effective August 30, 1985.
(5)   Amendment effective September 17, 1979.
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                     (30-8)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
20.   Clubs for golf, tennis, swimming and similar facilities             P      P      P      N       N     N     N     P     P
      whether conducted as a business for profit or not, with
      or without a liquor permit, subject to the following
      conditions:

      a.    Golf facilities shall be located on a lot of not
            less than 50 acres or, if in combination with
            tennis, swimming, or similar facilities, not less
            than 60 acres. Tennis, swimming and similar
            facilities alone shall be located on a lot of not
            less than 10 acres.
      b.    Unless located in an I-1, or I-2 zone, all club
            facilities, including club house, pro shop,
            restaurant, bar, locker rooms, or recreation hall
            shall be located not less than 200 feet from any
            property line and parking area and accessory
            buildings shall be located not less than 150 feet
            from any property line. If any of the above are
            located in an I-1 or I-2 zone, the normal
            dimensional requirements set forth in Section 32,
            Schedule B, shall apply, as well as the normal
            parking setback requirements for Industrial zones
            as set forth in Section 33.1 and parking
            requirements as set forth in Section 33.1.7.(1)
      c.    A single indirectly lighted sign of not more than
            six square feet single side area, nor more than
            six feet in height as measured from the ground may
            be maintained not less than 20 feet from any
            property line.
      d.    The furnishing of meals, refreshments, beverages
            and entertainment shall be incidental to the
            conduct of the facility, and provided that
            three-quarters of the customers' seats are located
            within an enclosed building of the facility. There
            shall be no living accommodations except for
            employees of the club.
      e.    Golf facilities shall be so designated and located
            that there is no hazard to persons or property off
            the premises. A11 tees shall be located no less
            than 30 feet from any property line. There shall
            be no artificial lighting on the course itself and
            no play permitted alter darkness.

(1)   Amendment effective April 17, 1972.
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                     (30-9)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>

21.   Assisted living, convalescent homes, and the like                   P      P      P      P       N     N     N     N     N
      licensed by the State of Connecticut subject to the
      following conditions:(3)
      a.    The facility shall be the only building on a lot
            of no less than 10 acres in area.
      b.    The facility shall meet the following dimensional
            requirements:
              Minimum setback from street line          150 ft.
              Minimum setback from sideline              50 ft.
              Minimum setback from rear line            100 ft.
              Maximum height of structure               40 ft.
              Maximum lot coverage                       10 %

      c.    In addition to the above requirements, a minimum
            of 50% of the total area shall be landscaped or
            designated as open space.
      d.    Parking in assisted living residential facilities
            shall be a minimum of one (1) per every three (3)
            dwelling units and on (1) for every employee on
            the largest shift.
      e.    As part of the filing requirements for the special
            permit, the applicant shall submit a profile
            drawing to scale showing the proposed facility and
            its relationship to buildings on both sides
            for a distance of 500'. The commission may
            require additional information necessary to assist
            them it determining the scale of the proposed
            structure(s) in relation to the surrounding area.
            This additional information may include visual
            representations of the project such as, but not
            limited to, architectural models made to scale,
            additional renderings, etc.
---------------------------------------------------------------------------------------------------------------------------------
21A.  Facilities for the retarded and/or autistic, licensed by            P      P      P      P       N     N     N     N     N
      the State of Connecticut and subject to the following
      conditions:
      a.    The facility shall be located on a lot not less
            than ten (10) acres in area.
      b.    There shall not be more than thirty-six (36)
            individua1 residents on the premises at any one
            time. Residential dwellings shall be separate
            buildings containing six (6) or less residents plus
            the appropriate staff personnel.
      c.    If the facility provides educational services, no
            more than twenty (20) additional students shall be
            allowed Classrooms, recreation, administration and
            other similar activities may be housed in a
            separate building.
      d.    All structures shall be located at least 100 feet
            from all property lines.(l)
---------------------------------------------------------------------------------------------------------------------------------
22.   Parks and play grounds, historic landmarks, and the like,           P      P      P      P       P     P     P     P     P
      operated by a private or governmental unit or a community
      association.
</TABLE>

<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
23.   Campgrounds (cont.)                                                 P      P      N      N       N     N     N     N     P

      c.    Access roads at the entrance shall be paved to
            Town standards for quality and shall be a minimum
            of 22 feet wide.
      d.    The check-in station or office shall be at least
            500 feet from the entrance intersection and shall
            have adequate paved parking to avoid congestion.
            (1 space for each employee and a minimum of 5
            visitor's spaces.)
      e.    Interior circulation shall be by one-way system
            where feasible. Such one-way roads shall be 12
            feet wide and shall be oiled.
      f.    No campsite shall be closer to the state highway
            than 500 feet nor closer than 300 feet from any
            other property line.
      g.    There shall be no more than four campsites per
            acre. For each such developed acre, 2 undeveloped
            acres shall be required.
      h.    No campground shall have less than a minimum of 5O
            acres.
      i.    All campsites devoted to tenting shall be on
            well-drained gravel sites.
      j.    Tenting areas shall be protected from vehicular
            traffic.
      k.    Rubbish shall be collected daily from all
            campsites.
      1.    Potable crater supply and sanitary facilities
            shall meet State Health requirements. In addition,
            all toilets shall be flush-type.
      m.    Water retention ponds and other precautions for
            fire protection shall be developed as per request
            of Town of Cheshire Fire Marshal.
      n.    There shall be a 14-day maximum occupancy limit
            during any 90-day period.(1)
---------------------------------------------------------------------------------------------------------------------------------
24.   Hotels, motels, tourist courts and the like, designed               N      N      N      N       N     N     N     N     P
      primarily for transient guests and subject to the
      following conditions:

      a.    The facility shall be located on a lot of not less
            than 120,000 square feet in area and there shall be
            not less than 4,000 square feet of land area for
            each guest unit on the premises and not less than
            20,000 square feet of land area for each guest
            unit equipped with kitchen facilities.

(1)   Amendment effective February 27, 1975.
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                    (30-11)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
24.   Hotels (cont.)

      b.    The facility shall be served by a public water                N      N      N      N       N     N     P     N     P
            supply system or a state-approved community water
            supply system.
      c.    The front and rear setbacks shall not be less than
            100 feet and side line setbacks not less than 50
            feet.
      d.    No more than 20 percent of the units shall have
            kitchen facilities.
      e.    This section shall not be held to permit trailer
            parks or camps.
---------------------------------------------------------------------------------------------------------------------------------
25.   Privately owned and managed ambulance services certified            N      N      N      P       P     P     P     P     P
      as required by the Connecticut General Statutes as
      amended.(1)
      (0riginal Para. 25 Restaurants, deleted by Commission
      action on 2/26/79)
---------------------------------------------------------------------------------------------------------------------------------
26.   a.    Restaurants and other food service establishments,            N      N      N      N       S     S     S     P     P
            with or without a liquor permit, provided at least
            three quarters of the customer seats are located
            within an enclosed building. Restaurants and other
            food service establishments when in industrial
            zones shall not be constructed or located within
            2,000 feet of any existing or proposed
            restaurants. Distances shall be measured between
            the nearest point of the nearest adjacent sides of
            the existing and proposed restaurants.(2),(4)

      b.    Such uses may include a food take-out service
            incidental to the primary permitted use where
            customers are served in motor vehicles.(4)
---------------------------------------------------------------------------------------------------------------------------------
27.   Ice cream parlors, where ice cream, soda and ice cream              N      N      N      N       S     S     S     N     N
      associated products are the only items sold provided
      customers are served only when inside the building, and
      further provided there is a minimum of ten seats located
      inside the building for use by customers. Parking shall
      conform to Paragraph 31.1.7 of these Regulations.(3)
---------------------------------------------------------------------------------------------------------------------------------
(1)   Amendment effective May 2, 1988
(2)   Amendment effective March 2, 1979.
(3)   Amendment effective July 22, 1976.
(4)   Amendment effective September 30, 1994.
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                    (30-12)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
                                                                                                             **    **    *
23.   Gasoline stations (wholesale and retail) with or without            N      N      N      N       N     P     P     P     N
      repairer's license and Repairers subject to the
      following conditions and certifications as required by
      the Connecticut General Statutes as amended - gasoline
      stations (wholesale and retail) with or without a
      repairer's license and Repairers.

      a.    Any petroleum or other inflammable products stored
            above ground shall be contained in drums or
            containers of not more than 55 gallons, except
            that fuel oils to be consumed on the premises may
            be stored in a 275 gallon tank.
      b.    The facility shall be located on a lot having a
            frontage of at least 150 feet on a street and
            having a land area of at least 30,000 square feet.
      c.    All gasoline pump islands shall be located at
            least 25 feet from all lot lines.
      d.    No curb-cut shall be greater than 30 feet in width
            and no part of any curb-cut shall be within 25
            feet of any side or rear line or street
            intersection. All curb-cuts shall be clearly
            defined by curbing.
      e.    Gas stations with full repairer's license shall be
            permitted provided such use be located on a lot
            having a frontage of at least 150 feet on a street
            and having a land area of at least 40,000 square
            feet.
      f.    All accessory equipment or merchandise displayed
            outside shall be no more than 10 feet from the
            building with the exception that such merchandise
            and accessory equipment shall be permitted to be
            displayed on the pump island.
      g.    After the effective date of this amendment to this
            section and these regulations, no retail or
            wholesale gasoline station shall be constructed or
            located within fifteen hundred feet (1,500) of an
            existing gasoline filling station (retail or
            wholesale).

(1)   Amendment effective March 12, 1971.
*     Effective December 30, 1983 ** Effective 6/8/90
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                     (30-13)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
                                                                                                                   #     *     #
29.   Motor vehicle dealers (which can have repairer's                    N      N      N      N       N     N     P     P     P
      licenses by State Statutes) subject to the following
      conditions and certification as required by the
      Connecticut General Statutes as amended.

      a.    Any petroleum or other inflammable products stored
            above ground shall be contained in drums or
            containers of not more than 55 gallons, except
            truck fuel oils to be consumed on the premises may
            be stored in a 275 gallon tank

      b.    The facility shall be located on a lot having a
            frontage of at least 150 feet on a street and
            having a land area of 40,000 square feet.

      c.    Outside accessory equipment or structures shall be
            located at least 25 feet from all lot lines.

      d.    No curb-cut shall be within 25 feet of any side or
            rear line or street intersection. All curb-cuts
            shall be clearly defined by curbing.
---------------------------------------------------------------------------------------------------------------------------------
30.   Automatic Car Washing and Cleaning Establishments. An
      establishment equipped to wash automobiles, pick-up
      trucks, and small vans. The car wash shall be fully
      automatic enabling the driver to remain in the vehicle
      as it is washed. It shall be in a completely enclosed
      building./2/

/1/   Amendment effective March 12, 1971.
/2/   Amendment effective February 27, 1987
*     Effective December 30, 1983
**    Effective December 19, 1986
#     Effective June 8, 1990
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                    (30-14)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>

31.   Commercial and Boarding Kennels and Veterinary hospitals            P      P      P      N       N     N     N     P     S
      subject to the following conditions:

      a.    No dogs shall be housed or exercised in outside
            kennels or runs.
      b.    A11 buildings in which dogs are housed or
            exercised shall be of solid construction of either
            masonary or framed with insulation and shall have
            finished interior walls.
      c.    Exercise runs shall have finished masonary floor
            with covered drains, and shall be separated by
            solid partitions of at least 4 feet in height.
      d.    All external doors shall be of solid core
            construction.
      e.    Kennel rooms and exercise runs shall be provided
            with forced air ventilation and shall have no open
            windows.
      f.    A11 ceilings shall be insulated and finished with
            sound absorbent materials.
      g.    In residential zones, the facility shall be on a
            lot with a minimum area of 5 acres and any
            building housing animals shall be at least 150
            feet from any property line.
      h.    In industrial zones, the facility shall be on a
            lot with a minimum area of 100,000 square feet, a
            minimum lot width of 250 feet and subject to the
            frontage setback, height and lot coverage
            requirements of the I-3 zone.
---------------------------------------------------------------------------------------------------------------------------------
32.   Horses or ponies for hire, riding academies or boarding             P      P      P      N       N     N     N     P     P
      stables for five or more animals located on a lot of not
      less than 15 acres provided that any building (other
      than a dwelling) and riding ring shall be located at
      least 300 feet from any lot line.
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                    (30-15)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
33.   Professional and Business offices.                                  N      N      N      P       S     S     S     P     S
---------------------------------------------------------------------------------------------------------------------------------
34.   Banks and Other Financial Institutions.                             N      N      N      P       S     S     S     P     S
---------------------------------------------------------------------------------------------------------------------------------
35.   Stores and other buildings and structures where goods               N      N      N      N       N     S     S     N     N
      are sold or service is rendered primarily at retail
      including self-service clothes cleaning establishments
      and including cleaning equipment incidental to the
      retail business of the store.
---------------------------------------------------------------------------------------------------------------------------------
36.   Stores and other buildings and structures not more than             N      N      N      N       S     S     S     N     N
      a total of 2,000 sq. ft. of gross floor area per whole
      structure, the use of which in whole or in part is for
      the sale of goods or rendering of services primarily at
      retail and including self-service clothes cleaning
      establishments and cleaning equipment incidental to the
      retail business of the store.(1)
---------------------------------------------------------------------------------------------------------------------------------
37.   Undertaker's establishments on a lot of at least 40,000             N      N      N      P       S     S     S     N     N
      sq. ft. in area subject to the following conditions:

      a.    The lot shall have at least 150 feet of frontage
            on the street.
      b.    The principal building shall not extend to within
            less than 60 feet of the front line.
      c.    Parking shall be in the rear of the principal
            building
      d.    Vehicular access shall be at least 20 feet from
            any side or rear line.
---------------------------------------------------------------------------------------------------------------------------------
                                                                                                                         *
38.   Radio and television-broadcasting studios excluding                 N      N      N      N       N     S     S     P     S
      transmitting and receiving towers in excess of 35 feet
      above the ground.

(1)   Amendment effective September 26, 1974.
*     Effective December 30, 1983
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                    (30-16)
<PAGE>

SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------------
                                                                                              ZONING  DISTRICTS
                                                                         --------------------------------------------------------
      PERMITTED USES                                                     R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
---------------------------------------------------------------------------------------------------------------------------------
<S>                                                                       <C>    <C>    <C>    <C>     <C>   <C>   <C>   <C>   <C>
39A.  Commercial recreation facilities provided the use is the            N      N      N      N       N     N     P     P     N
      only use on a lot not less than 30,000 square feet in
      area and that the use is located primarily within an
      enclosed building.

39B.  Indoor ice skating facilities provided the use is                   N      N      N      N       N     N     S     P     S
      located entirely within an enclosed building or
      buildings when requirements of the facility and the
      provisions of these regulations require a lot of not
      less than 120,000 square feet in area.(2)

39C.  Sports Training Facilities with related commercial                  N      N      N      N       N     N     P     P     P
      recreational facilities provided the use is the only use
      on a lot not less than 40,000 square feet in area.
      Sports training facilities located in an enclosed
      building with related outdoor facilities shall not be
      located on any lot with frontage on Route 10 or with
      direct access to Route 10. Any outdoor facilities,
      although open to the public, shall be secondary to the
      primary sports training use, and shall be limited to use
      for baseball, soccer, lacrosse, tennis, field hockey,
      basketball and footba11.(7)
---------------------------------------------------------------------------------------------------------------------------------
                                                                                                                         *
40.   Printing and publishing establishments occupying not                N      N      N      N       N     S     S     P     S
      more than 2,500 square feet of floor area.
---------------------------------------------------------------------------------------------------------------------------------
                                                                                                                         *
41.   Printing and publishing establishments                              N      N      N      N       N     N     N     P     S
---------------------------------------------------------------------------------------------------------------------------------
42.   Medical clinics and laboratories and dental clinics and             N      N      N      P       S     S     S     N     N
      laboratories.
---------------------------------------------------------------------------------------------------------------------------------
                                                                                                                         *
43.   Research Laboratories.                                              N      N      N      N       N     N     N     P     S
---------------------------------------------------------------------------------------------------------------------------------
                                                                                                                         *
44.   The manufacture, processing, assembling of goods and                N      N      N      N       N     N     N     P     S
      storage incidental to the primary use.(3)
---------------------------------------------------------------------------------------------------------------------------------
                                                                                                                         *
45.   Warehousing, wholesale business and wholesale business              N      N      N      N       N     N     P     P     S
      warehousing.
---------------------------------------------------------------------------------------------------------------------------------
                                                                                                                         *
46A.  Contractor's warehousing and storage yards.(4)                      N      N      N      N       N     N     N     P     S
                                                                                                                         *
46B.  Excavation, contractors and paving contractors,                     N      N      N      N       N     N     N     P     S
      business and equipment storage yards.
---------------------------------------------------------------------------------------------------------------------------------
                                                                                                                         *
47.   Lumber and building materials business and storage                  N      N      N      N       N     N     N     P     S
      yards.
---------------------------------------------------------------------------------------------------------------------------------
1 & 2 Amendment effective April 29, 1976.
3     Amendment effective September 1, 1975.
4     46 renumbered to 46A, effective September 1,1975.
5     Amendment effective September 1, 1975.
6     Amendment effective May 8, 1978.
*     Effective December 30, 1983.
7     Amendment effective July 29, 1994.
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                               (30-17)
<PAGE>

        SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------
                                                                   ZONING DISTRICTS
                                               -------------------------------------------------------------
        PERMITTED USES                         R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
------------------------------------------------------------------------------------------------------------
<S>     <C>                                      <C>   <C>    <C>     <C>    <C>   <C>   <C>   <C>   <C>
48.     Freight and materials trucking           N     N      N       N      N     N     N     P     S
        businesses, freight terminals and
        freight transshipment facilities.(1)
------------------------------------------------------------------------------------------------------------
49.     Laundry, cleaning and dyeing plants.     N     N      N       N      N     N     N     P     P
------------------------------------------------------------------------------------------------------------
50.     Plants, other than bona fide farms,      N     N      N       N      N     N     N     P     S
        for the processing and distribution
        of milk and edible dairy products.
        Plants for the packaging and
        distribution of beverages.
------------------------------------------------------------------------------------------------------------
51.     Commercial storage and sale of fuel      N     N      N       N      N     N     P     P     S
        and bottled gas. Total above ground
        tank capacity shall not be more than
        30,000 gallons and no above ground
        tank shall be closer than 40 feet to
        any building.

51A.    Commercial storage and sale of bulk      N     N      N       N      N     N     N     Y     Y
        liquid oxygen for home health care
        and similiar uses shall require
        administrative approval by the
        Cheshire Fire Marshall, and the Town
        Planning office.(6)
------------------------------------------------------------------------------------------------------------
52      Painting, woodworking, sheet metal,      N     N      N       N      N     N     N     P     S
        blacksmiths, welding, tire recapping,
        machine shops and the like.
------------------------------------------------------------------------------------------------------------
53A.    Bulk storage of cement and concrete      N     N      N       N      N     N     N     N     S
        mixing plants.(2)

53B.    Bulk storage of petroleum and            N     N      N       N      N     N     N     N     P
        petroleum products and bituminous
        paving mixing plants.(3)
------------------------------------------------------------------------------------------------------------
54.     Commercial transmitting and receiving    N     N      N       N      N     N     N     P     S
        antenna, with enclosure for
        associated equipment, in excess of 35
        feet but less than 100 feet above the
        ground in height provided the
        distance from any lot line shall be
        at least two times the height of the
        antenna.
------------------------------------------------------------------------------------------------------------
55.     Earth removal and filling in             N     N      N       N      P     P     P     P     P
        accordance with Section 25.(4)
------------------------------------------------------------------------------------------------------------
56.     Screening, sifting, washing, crushing    N     N      N       N      N     N     N     P     P
        bulk storage of, and other forms of
        processing of sand, stone, gravel, and
        the like.(5)
------------------------------------------------------------------------------------------------------------
</TABLE>

1,2,3,5 Amendments effective September 1, 1975
 4 Amendment effective February 27, 1975
 * Effective December 30, 1983
 6 Amendment effective May 28, 1993.

                                     (30-18)
<PAGE>

        SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------
                                                                   ZONING DISTRICTS
                                               -------------------------------------------------------------
        PERMITTED USES                         R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
------------------------------------------------------------------------------------------------------------
<S>     <C>                                      <C>   <C>    <C>     <C>    <C>   <C>   <C>   <C>   <C>
57.     Golf driving ranges.                     N     N      N       N      N     N     N     N     P
------------------------------------------------------------------------------------------------------------
58.     Carnivals or fairs sponsored by a        N     P      P       P      P     P     P     P     P
        local non-profit organization,
        subject to the following conditions:

        a.  The facility shall be on a lot
            having a minimum area of 3 acres.
        b.  There shall be provision for
            adequate parking within 500 feet
            of the facility.
        c.  All structures shall be a
            minimum of 150 feet from any lot
            line.
        d.  Direct access shall be on lands
            adjacent to State Highway Routes
            10 or 70.
        e.  Two signs may be allowed for a
            period not to exceed the duration
            of the event and two weeks
            immediately preceding the event.
        f.  There shall be no more than one
            special permit issued to an
            organization during any one
            calendar year. The duration
            shall be for no more than 10
            consecutive calendar days.
        g.  Subsequent yearly events
            sponsored by the same
            organization and located on the
            same site may be approved
            administratively by the Planning
            Staff.
------------------------------------------------------------------------------------------------------------
59.     Temporary fairs, bazaars and sales of    Y     Y      Y       Y      Y     Y     Y     Y     Y
        local non-profit organizations held
        on premises, the majority of which
        are owned by the sponsoring
        organization, subject to the
        following conditions:

        a.  Duration shall not be more than
            10 consecutive calendar days
            during any one calendar year.
        b.  There shall be provision for
            adequate parking within 500 feet
            of the facility.
        c.  Two signs may be allowed for a
            period not exceed the duration
            of the event and the two weeks
            immediately preceding the event.
</TABLE>

(1) Amendment effective 7/02/93.
--------------------------------------------------------------------------------

                                     (30-19)
<PAGE>

        SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------
                                                                   ZONING DISTRICTS
                                               -------------------------------------------------------------
        PERMITTED USES                         R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
------------------------------------------------------------------------------------------------------------
<S>     <C>                                      <C>   <C>    <C>     <C>    <C>   <C>   <C>   <C>   <C>
60.     Accessory uses customarily associated    Y     Y      Y       Y      N     N     N     N     N
        with or incidental to any permitted
        use in any residential zone subject
        to the following conditions:

        a.  Accessory uses may include
            private garages for the use of
            the occupants of the lot. One
            garage space may be rented to a
            non-resident of the lot provided
            the garage space is not one of
            the spaces required in Section
            33.1.1 and the use of the rented
            space meets all other
            requirements of the Zoning
            Regulations.
        b.  Buildings and structures for
            recreational and homeowner
            association use in approved
            Planned Residential Developments
            and Cluster Subdivisions shall
            be considered accessory uses.
        c.  All accessory buildings shall
            meet the requirements of Section
            32.2.5.
        d.  Except as provided elsewhere in
            these Regulations, such uses
            shall not include the sale of
            articles not made on the
            premises, nor a restaurant, or
            other food service
            establishment, beauty parlor or
            other hairdressing
            establishment, and the like.
        e.  No accessory use shall change
            the residential character of the
            area.(1)
------------------------------------------------------------------------------------------------------------
61.     Clubhouses for non-profit, fraternal,    N     N      N       N      N     P     P     N     N
        community service and/or veteran's
        organizations with or without a
        liquor permit. Parking requirements
        shall be in accordance with Section
        33.1.2.(2)
</TABLE>

(1) Amendment effective September 25, 1975.
(2) Amendment effective November 29, 1972.
--------------------------------------------------------------------------------

                                     (30-20)
<PAGE>

        SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------
                                                                   ZONING DISTRICTS
                                               -------------------------------------------------------------
        PERMITTED USES                         R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
------------------------------------------------------------------------------------------------------------
<S>     <C>                                      <C>   <C>    <C>     <C>    <C>   <C>   <C>   <C>   <C>
62.     Temporary political signs pertaining     Y     Y      Y       Y      Y     Y     Y     Y     Y
        to candidates, political parties or
        political issues in a National, State
        or Municipal election for a period of
        60 days prior to and 7 days
        subsequent to said election, subject
        to the following:

        a.  No more than one sign per lot,
            not to exceed: 6 square feet in
            the R-80, R-40, R-20 and R-20A
            zones; 32 square feet in the
            C-1, C-2, C-3, I-1 and I-2
            zones. (1)

        b.  Regardless of zone, one 32
            square foot free-standing sign
            and wall signs covering the
            front or entrance wall shall be
            allowed for one Townwide
            headquarters per political
            party. (1)

        c.  The responsibility for removal
            of signs shall lie with the
            individual or individuals
            posting said sign or signs. (2)
</TABLE>

(1) Amendment effective July 1, 1983
(2) Amendment effective September 1, 1975
--------------------------------------------------------------------------------

                                     (30-21)
<PAGE>

        SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------
                                                                   ZONING DISTRICTS
                                               -------------------------------------------------------------
        PERMITTED USES                         R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
------------------------------------------------------------------------------------------------------------
<S>     <C>                                      <C>   <C>    <C>     <C>    <C>   <C>   <C>   <C>   <C>
64.     A temporary real estate office           Y     Y      Y       Y      Y     Y     Y     Y     Y
        located on the site of a Planned
        Residential Development, Cluster
        Subdivision, Resubdivision or Rental
        Apartment development approved by the
        Planning and Zoning Commission
        provided:

        a.  That the temporary real estate
            office is exclusively for the
            sale or rental of units or homes
            on the site on which said office
            is located.
        b.  That the temporary real estate
            office shall be located in one
            of the hones or units in the
            development.
        c.  That the temporary real estate
            office shall be permanently
            removed when 90 percent of the
            units or homes are initially
            sold or rented. (1)
------------------------------------------------------------------------------------------------------------
65.     A temporary construction office          Y     Y      Y       Y      Y     Y     Y     Y     Y
        provided:

        a.  That the temporary construction
            office shall be used exclusively
            for construction on the site on
            which it is located.
        b.  That the temporary construction
            office be located either in a
            model home or unit or in a
            movable trailer or trailers.
        c.  That the temporary construction
            office be permanently removed
            upon completion of all
            structures on the approved
            section of the site of the
            Planned Residential Development,
            Cluster Subdivision,
            Subdivision, Resubdivision, Site
            Plan, Special Permit, Planned
            Commercial Development, approved
            lot or lots of record. (2)
</TABLE>

(1) Amendment effective September 1, 1975.
(2) Amendment effective September 1, 1975.
--------------------------------------------------------------------------------

                                     (30-22)
<PAGE>

        SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------
                                                                   ZONING DISTRICTS
                                               -------------------------------------------------------------
        PERMITTED USES                         R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
------------------------------------------------------------------------------------------------------------
<S>     <C>                                      <C>   <C>    <C>     <C>    <C>   <C>   <C>   <C>   <C>
66.     Refuse Transfer and Recycling Centers    N     N      N       N      N     N     N     N     P
        -- Refuse contractors within enclosed
        buildings which shall include
        facilities for the transfer
        and sorting of refuse for the
        recycling of same providing that
        adequate buffer areas are provided
        between the structure and adjoining
        properties, and adequate on site
        measures shall be taken to prevent
        the activity from in any way
        affecting the adjoining properties.
        Nothing herein shall be construed to
        prevent on site storage in no more
        than two covered roll off containers
        which shall be located immediately
        adjacent to the facility subject,
        however, to the provisions relating
        to outside storage as set forth in
        Sections 32.7 and 32.7.1 of these
        regulations. (1)
------------------------------------------------------------------------------------------------------------
67A.    Sheltered Care Facility Designed         N     P      P       P      N     N     N     N     N
        Exclusively for Occupancy by Elderly
        Persons -- in accordance with the
        provisions of Section 43.6
------------------------------------------------------------------------------------------------------------
67B.    Planned Community Designed               N     P      P       P      N     N     N     N     N
        Exclusively for Occupancy by Elderly
        Persons Providing Interrelated
        Residential Units and Varying Levels
        of Nutritional and Health Care Units
        and Related Services -- in accordance
        with the provisions of Section 43.7
------------------------------------------------------------------------------------------------------------
68.     Helioports and storage facilities for    N     N      N       N      N     N     N     P     P
        helicopters, excluding emergency
        helicopters, subject to the following:

             Helioports must be located on
             lots of at least 10 acres and no
             portion of the landing area may
             be closer than 300 feet from the
             nearest property line. All
             helioports shall meet the
             standards and conditions set by
             the State of Connecticut,
             Department of Aeronautics.(2)
------------------------------------------------------------------------------------------------------------
</TABLE>

(2) Amendment effective December 24, 1987.

(1) Amendment effective August 31, 1979.
--------------------------------------------------------------------------------

                                     (30-23)

<PAGE>

        SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------
                                                                   ZONING DISTRICTS
                                               -------------------------------------------------------------
        PERMITTED USES                         R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
------------------------------------------------------------------------------------------------------------
<S>     <C>                                      <C>   <C>    <C>     <C>    <C>   <C>   <C>   <C>   <C>
69.     Health and Exercise Facilities. (1)      N     N      N       P      S     S     S     P     S
------------------------------------------------------------------------------------------------------------
70.     Boat dealers, to include sales and       N     N      N       N      N     N     P     P     P
        service of boats, motors, boat
        trailers and related accessories,
        subject to the following conditions:

         a.  Any petroleum or other
             inflammable products stored
             above ground shall be contained
             in drums or containers of not
             more than 55 gallons, except
             that fuel oils to be consumed on
             the premises may be stored in a
             275 gallon tank.

         b.  The facility shall be located on
             a lot having a frontage of at
             least 150 feet on a street and
             having a land area of 40,000
             square feet.

         c.  No curb-cut shall be within 25
             feet of any side or rear line or
             street intersection. All
             curb-cuts shall be clearly
             defined by curbing. (2)
------------------------------------------------------------------------------------------------------------
71.     The sale of registered motor vehicles    Y     Y      Y       Y      Y     Y     Y     Y     Y
        on a residential lot and subject to
        the following conditions:

         a.  The motor vehicle for sale shall
             not exceed a rated capacity of
             two and one-half (2 1/2) tons. In
             addition, such vehicles shall be
             registered in the name of and/or
             be the legal property of a
             resident of the dwelling unit.

         b.  No more than two (2) motor
             vehicles shall be offered for
             sale or sold from any one lot in
             the period of one calendar year. (3)
</TABLE>

(1) Amendment effective April 29, 1988.
(2) Amendment effective May 27, 1988.
(3) Amendment effective September 30, 1988.
--------------------------------------------------------------------------------

                                     (30-24)
<PAGE>

        SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------
                                                                   ZONING DISTRICTS
                                               -------------------------------------------------------------
        PERMITTED USES                         R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
------------------------------------------------------------------------------------------------------------
<S>     <C>                                      <C>   <C>    <C>     <C>    <C>   <C>   <C>   <C>   <C>
72.     The Sale and Display of Antiques (1)     P     P      P       P      S     S     S     N     N

        "Antiques" for the purpose of these
        regulations are defined as any work
        of art, piece of furniture,
        decorative object, and the like,
        created and produced at least 25
        years prior to the date of sale.
        The sale and display of antiques
        subject to the following conditions:
        1.  Additional storage is permitted
            in an ancillary building
            provided it is entirely enclosed
            within another building.

        2.  There shall be no external
            evidence of such use other than
            permitted signage as provided in
            Section 34.1.1 for Residential
            Zone and 34.1.4 in Commercial
            Zones.

        3.  There shall be a minimum of five
            (5) parking spaces provided on
            the site.

        4.  In Residential Zones:

            a.  property must have frontage
                onto a State Highway
            b.  such use must be secondary
                to the residential use of
                the entire premises and
                shall not occupy more then
                50% of the floor area in the
                residence wherein located.
------------------------------------------------------------------------------------------------------------
73.     Hair and Beauty Salons (2)              N     N      N       P      P     P     P    P*    P*
        (including barber shops)

        *   When in industrial zones shall
            not be constructed or located
            within 1,000 feet of any
            existing or proposed hair or
            beauty salon.

            a.  Distances shall be
                measured between the
                nearest adjacent sides of
                the existing and proposed
                beauty salons.

            b.  Parking requirements shall
                be according to Section
                33.1.7 standards.
</TABLE>

(1) Amendment effective March 31, 1995.
(2) Amendment effective April 26, 1996 at 12:01 A.M.
--------------------------------------------------------------------------------

                                     (30-25)
<PAGE>

        SECTION 30, SCHEDULE A, PERMITTED USES

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------
                                                                   ZONING DISTRICTS
                                               -------------------------------------------------------------
        PERMITTED USES                         R-80   R-40   R-20   R-20A   C-1   C-2   C-3   I-1   I-2
------------------------------------------------------------------------------------------------------------
<S>     <C>                                      <C>   <C>    <C>     <C>    <C>   <C>   <C>   <C>   <C>
74.     ADULT ENTERTAINMENT (1)                  N     N      N       N      N     N     N     P     P

Businesses providing adult entertainment
shall not be located within 500 feet of any
other such business nor within 2,000 feet of
any public or private school or day care
center, church, synagogue, or other similar
place of worship; public park, playground, or
other recreational facility where large
numbers of minors regularly congregate:
library: funeral home: or residentially zoned
or residentially used property. The distance
shall be measured in a straight line from the
nearest edge of the building or zoning
district boundary line, as applicable. Adult
entertainment shall include, but not be
limited to, the following: Topless dancing or
any dancing or performance which involves
nudity, which involves the removal of
clothing such that partial or complete nudity
results, which involves the fondling of the
genitals of the dancer or performer or the
genitals of another person, or which involves
sexual intercourse or deviate sexual conduct.
Nudity is defined as the showing of the male
or female genitals, pubic area or buttocks
with a less than fully opaque covering; the
showing of the female breast with less than a
fully opaque covering of any part of the
nipple; or the showing of the male genitals
in a discernibly turgid state.

------------------------------------------------------------------------------------------------------------
75.     Pet Grooming (2)                         N     N      N       P      P     P     P    P*    P*

        *When in industrial zones shall not
         be constructed or located within
         1,000 of an existing or proposed pet
         groomer.
               a.  Distance shall be measured
                   between the nearest
                   adjacent sides of the
                   existing and proposed pet
                   groomers.
               b.  No dogs shall be housed
                   outside.
               c.  Parking requirements shall
                   be according to Section
                   33.1.7 Standards.
------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------
</TABLE>

(1) Amendment effective June 7, 1996. (30-26)

<PAGE>

                                    EXHIBIT H
                                   PAGE 1 0F 2

             [Graphic Omitted: Plan for proposed expansion of premises]

                                     PLAN A
<PAGE>

                                    EXHIBIT H
                                   PAGE 2 0F 2

             [Graphic Omitted: Plan for proposed expansion of premises]

                                     PLAN B
<PAGE>

                                    EXHIBIT I

All that certain parcel of land, with the buildings and improvements located
thereon, situated on the southerly side of Knotter Drive In the Town of
Cheshire, County of New Haven and State of Connecticut, and being shown on a map
entitled "Plan Prepared for WE Knotter, LLC. 350 Knotter Drive Cheshire, Conn.
ALTA/ACSM Land Title Survey Scale: 1" = 100' Date: 10-25-1999 Design: RED Draft:
SLH Project: 99267" made by Meehan & Goodin, Engineers - Surveyors, P.C., which
map is on file in the Town Clerk's Office in the Town of Cheshire to which
reference may be had. Said premises are more particularly bounded and described
as follows:

Beginning at a point with State Coordinates N 259654.677. E 552480.562, which
point marks the southwesterly corner of the herein described parcel;

Thence N 21(degrees) 48' 52" E along land now or formerly of Bloomingdale's By
Mail, Ltd., a distance of 1,419.365 feet to a point;

Thence by a curve to the left having a delta angle of 55(degrees) 30' 00" and a
radius of 780.00 feet along the southerly line of Knotter Drive. an arc distance
of 755.553 feet to a point;

Thence N 30(degrees) 00' 00" E along the southerly line of Knotter Drive, a
distance of 2.362 feet to a point;

Thence S 62(degrees) 56' 39" E along land now or formerly of Louis Deberadinis,
a distance of 1,516.538 feet to a point;

Thence S 32(degrees) 57' 00" W along land now or formerly of JMJ Associates,
LLC, a distance of 154.399 feet to a point;

Thence S 30(degrees) 36' 32" W partly along land now or formerly of JMJ
Associates, LLC, and partly along land now or formerly of Bloomingdale's by
Mail, Ltd., in all, a distance of 316.871 feet to a point;

Thence S 9(degrees) 05' 30" W along land now or formerly of Bloomingdale's by
Mail, Ltd., a distance of 40.430 feet to a point;

Thence S 18(degrees) 19' 16" W along land now or formerly of Bloomingdale's by
Mail, Ltd., a distance of 436.678 feet to a point;

Thence N 72(degrees) 24' 33" W along land now or formerly of Bloomingdale's by
Mail, Ltd., a distance of 308.701 feet to a point;

Thence S 21(degrees) 48' 52" W along land now or formerly of Bloomingdale's by
Mail, Ltd., a distance of 1.020.833 feet to a point;

Thence N 49(degrees) 53' 17" W along land now or formerly of Bloomingdale's by
Mail, Ltd., a distance of 357.475 feet to a point;

Thence N 68(degrees) 11' 08" W along land now or formerly of Bloomingdale's by
Mail, Ltd., a distance of 1.246.798 feet to the point or place of beginning.
<PAGE>

                                    Exhibit J

                                Tenant's Property

Air-cooled condensing units (Alexion supplied)
Air dryers -- compressed air (Alexion supplied)
Autoclaves (Alexion supplied)
Automated transfer switches (Alexion supplied)
Back-up generators (Alexion supplied)
Process boilers (Alexion supplied)
HVAC boilers (Alexion supplied)
Ceiling mounted HEPA filter modules (Alexion supplied) (Alexion supplied)
Process chillers and associated pumps and tanks (Alexion supplied)
HVAC chillers and associated pumps and tanks (Alexion supplied)
Clean cold rooms with associated condensing units and controls (Alexion
       supplied)
Computer networks (Alexion supplied)
Control systems (Alexion supplied)
Controlled environment enclosures and rooms (Alexion supplied)
Electrical panels (Alexion supplied)
Electrical power conditions (Alexion supplied)
Electrical step-down transformers (Alexion supplied)
Fermentors (Alexion supplied)
Fume hoods (Alexion supplied)
Glassware washer (Alexion supplied)
Heat exchangers (Alexion supplied)
Hoists (Alexion supplied)
Intercom systems (Alexion supplied)
Lab casework/furniture including, but not limited to, lab benches, hoods and
       shelving units (Alexion supplied)
Motor disconnects / Motor starters (Alexion supplied)
Phone systems (Alexion supplied)
Pressure reducing valves (Alexion supplied)
Reheat packages with associated pumps and tanks (Alexion supplied)
Security systems (Alexion supplied)
Single phasing protection units (Alexion supplied)
Stainless steel piping/valves/pumps (Alexion supplied)
Stainless steel sinks (Alexion supplied)
Stainless steel tanks (Alexion supplied)
Steam pressure reducing stations (Alexion supplied)
Stills (Alexion supplied)
Vacuum pumps (Alexion supplied)
Variable frequency drivers (Alexion supplied)
Waste neutralization systems (Alexion supplied)
Water filters (Alexion supplied)
Water softeners (Alexion supplied)
Water systems (Alexion supplied)

                                 April 27, 2000
<PAGE>

                                    EXHIBIT K

                              PERMITTED REMOVABLES

Arch Chemicals condition of vacated space at 350 Knotter Drive, Cheshire, CT.

1.    Removal of Halon Sprinkler System from several of the Chemical labs. This
      system is no longer an DEP approved sprinkler system.

2.    Arch Chemicals plans on removing all personal equipment from the space.
      All cabinets, hoods, benches or other equipment that is permanently
      affixed to the floor would stay.

3     The plastic snorkels from the ceiling to lab counters will be removed

4.    Light Panel in Room 284 will be removed

5.    Gas Cylinders and Specialized DI Water Equipment will be removed

6.    In the Library all bookshelves will be removed. The tracking bookshelves
      will stay.

7.    Unattached center benches in Room E-10 & D10 will be removed. The
      attached bench with drawers and the four attached floor-standing cabinets
      in Room E-10 will removed.

8.    Shelving in the stock room will be removed

9.    All attached cafeteria equipment will stay, but tables and chairs will be
      removed.

                                        6
<PAGE>

                                    EXHIBIT L

                                [GRAPHIC OMITTED]

                                AREA 2 FLOOR PLAN
<PAGE>

                                    EXHIBIT M

                                VO. 242 PAGE 219

                                                                              10

Reservations
                                  WARRANTY DEED

TO ALL PEOPLE TO WHOM THESE PRESENTS SHALL COME, GREETING:

      KNOW YE, THAT F.I.P. CORPORATION, a Connecticut corporation with its
principal office in Farmington, Connecticut (hereinafter referred to as the
Grantor) for the consideration of Ten Dollars ($10.00) and other valuable
considerations received to its full satisfaction of CONNECTICUT DEVELOPMENT
AUTHORITY, a body politic and corporate and public instrumentality of the State
of Connecticut, at 210 Washington Street, Hartford, Connecticut (hereinafter
referred to as the Grantee) does give, grant, bargain, sell and confirm unto the
said Grantee, its successors and assigns, forever, a certain piece or parcel of
land, with the improvements thereon and appurtenances thereto, situated on the
southeasterly side of FIP Road in the Cheshire Industrial Park in the Town of
Cheshire, County of New Haven and State of Connecticut, as shown on a map
entitled, "Siemens Corporation Cheshire Industrial Park The F.I.P. Corporation,
Developer Aug. 15, 1974 Scale: l" - 100' Cardinal Engineering Associates Inc."
which map is on file in the Town Clerk's Office in said Town of Cheshire, and
being more particularly bounded and described as follows:

      Beginning at a point with State Coordinates N 259 654.677, E 552 480.562.
which point is the southwest corner of the herein-described parcel; thence N
21(degrees) 48' 52" E, a distance of one thousand four hundred nineteen and
three hundred sixty-five one-thousandths (1419.365) feet along lands now or
formerly of P.F. Properties and Fisher Family Properties, in part by each, to a
point with State Coordinates N 260 972.404, E 553 008.001; thence in a
northeasterly direction in a curve to the left having a radius of seven hundred
eighty and no one-hundredths (780.00) feet, a distance of seven hundred
fifty-five and five hundred fifty-three one-thousandths (755.553) feet to a
point; thence N 30(degrees) 00' 00" E a distance of two and three hundred
sixty-two one-thousandths (2.362) feet to a point, the last two courses being
along FIP Road thence S 62(degrees) 51' 39" E, a distance of one thousand five
hundred sixteen and five hundred thirty-eight one-thousandths (1516.538) feet
along land now or formerly of T.R.W. Inc. to a point with State coordinates N
260 672.235, E 554 974.058; thence S 32(degrees)

                                         "No Conveyance Tax collected

                                          /s/ Warren E. Hall
                                          ---------------------------
                                            Town Clerk of Cheshire
<PAGE>

                                VO. 242 PAGE 220

57' 00" W a distance of one hundred fifty-four and three hundred ninety-nine
one-thousandths (154.399) feet to a point; thence S 30(degrees) 36' 32" W a
distance of three hundred sixteen and eight hundred seventy-one one-thousandths
(316.871) feet to a point, the last two courses being along land now or formerly
of Krampitz; thence S 9(degrees) 05' 30" W a distance of forty and four hundred
thirty one-thousandths (40.430) feet to a point: thence S 18(degrees) 19' 16" W
a distance of four hundred thirty-six and six hundred seventy-eight
one-thousandths (436.678) feet to a point; thence N 72(degrees) 24' 33" W a
distance of three hundred eight and seven hundred one one thousandths (308.701)
feet to a point; thence S 21(degrees) 48' 52" W a distance of one thousand
twenty and eight hundred thirty-three one-thousandths (1020.833) feet to a point
with State Coordinates N 258 961.049, E 553 911.472; thence N 49(degrees) 53'
17" W a distance of three hundred fifty-seven and four hundred seventy-five one-
thousandths (357.475) feet to an iron pin, the last five courses being along
land now or formerly of Highland Park: thence N 63(degrees) 11' 08" N along land
now or formerly of F. F. Properties a distance of one thousand two hundred
forty-six and seven hundred ninety-eight one-thousandths (1246.793) feet to the
point or place of beginning.

      Said parcel contains seventy-five (75) acres.

      No portion of FIP Road, as shown on said map, is conveyed hereby, such
road having been conveyed to the Town of Cheshire by deed of F. F. Properties
dated December 12, 1974 and recorded in Volume at Page of the Cheshire Land
Records.

      Together with the right to pass and repass over FIP Road for all customary
highway purposes.

      Said premises are conveyed subject to the following encumbrances:

      A. Any and all provisions of any ordinance, municipal regulation or public
law.

      B. Taxes to the Town of Cheshire on the applicable grand list at time of
closing which are liens against the premises not yet due and payable and any tax
or assessment for sanitary sewers which might be levied by municipal authority.

      C. Pipeline easements to the Algonquin Gas Transmission company as set
forth in the Cheshire Land Records at Volume 83, Page 154; Volume 108, Page 557;
Volume 83, Page 436: Volume 118, Page 107, Volume 138, Page 293, Volume 138,
Page 429.

      D. Drainage easement to the Town of Cheshire 20' in width abutting FIP
Road.

      Said premises are subject also to the following reserved rights and
covenants which shall run with the land and bind and inure to the benefit of the
Grantor, its successors and assigns, and the Grantee, its successors and
assigns:

      A. The unrestricted right in Grantor to discharge storm waters into the
existing natural water courses and such other water courses as may be agreed
upon by the parties on the premises to be conveyed subject to the rights of
downstream owners; provided, however, that such discharge shall not unreasonably
interfere with Grantee's right to discharge its own storm waters into

                                     - 2 -
<PAGE>

                                VO. 242 PAGE 221

said water courses or otherwise unreasonably interfere with Grantee's use of the
premises and Grantor will repair any damage to the premises caused by such
discharge and will indemnify and hold harmless Grantee from and against any
claim, damage or expense arising solely out of Grantor's exercise of such
discharge right.

      B. A right in Grantor to construct, use, maintain and replace such
underground utility and water and such drainage facilities on the premises as
Grantor may deem necessary for the proper development and operation of Cheshire
Industrial Park wherein the premises are located, provided, however, that such
facilities or the construction thereof shall not unreasonably interfere with the
use of the premises by Grantee and that such utility, water and drainage
facilities shall be located only within fifty (50) feet of the exterior boundary
lines of the premises and provided further that all expenses incurred in the
construction, use, maintenance and replacement of such facilities shall be borne
by Grantor and that upon completion of such construction the premises shall be
restored to their state prior to such construction, including relandscaping.

      C. A regulation that the ground floor area of the buildings shall not
exceed twenty (20) percent of the total area of the premises without the prior
written consent of the Grantor or its designees.

      D. A regulation that no building or buildings, site improvements or
alterations, signs or other structures shall be constructed on the premises nor
shall any addition thereto be constructed without the prior written approval of
Grantor or its designees of the plot plans, building plans and specifications
for such building or addition. Such approval shall not be withheld provided said
building and any additions thereto including signs shall harmonize in appearance
and be of substantially the same quality and workmanship as the other buildings
and structures in the Cheshire Industrial Park.

      E. Grantor shall establish or cause to be established an Association
within the Cheshire Industrial Park for the benefit of the owners and occupants
of the Park to be named "Cheshire Industrial Park Association". The purposes of
the Association shall be to protect and maintain the aesthetic beauty of the
Park and its grounds and improvements by regulations, restrictions and other
desirable means. Said Association when established shall be designated by the
Grantor to grant such approvals as are required from the Grantor whether by deed
or otherwise. The Association shall be established on or before January 1, 1990,
or sooner if at least seventy-five (75) percent of the land area constituting
Cheshire Industrial Park has been sold or otherwise conveyed to those who intend
to occupy the same. The Association shall be composed of owners of land and
occupants of facilities within said Park. All eligible entities who are members
shall be entitled to one vote as an occupant within the Park and one vote for
ownership for each ten acres or fraction thereof within the Park which vote may
be cast by the recorded owner or its designee. The rules when established by the
Association cannot be changed or amended except by the affirmative vote of
seventy-five (75) percent of those entitled to vote thereunder.

                                     - 3 -
<PAGE>

                                VO. 242 PAGE 222

      F. Grantor covenants that all of the land within Cheshire Industrial Park
shall be subject to reserved rights and covenants substantially similar to or
stricter (as respects the subserviant estate) as the foregoing reserved rights
and covenants; subject to such modifications thereto as Grantee shall approve.

      TO HAVE AND TO HOLD the above granted and bargained premises, with the
appurtenances thereof, unto it, the said Grantee, its successors and assigns
forever, to its and their own proper use and behoof. And also, it, the said
Grantor, does for itself. its successors and assigns, covenant with the said
Grantee, its successors and assigns, that at and until the ensealing of these
presents, it is well seized of the premises, as a good indefeasible estate in
FEE SIMPLE; and has good right to bargain and sell the same in manner and form
as is above written and that the same is free from all encumbrances whatsoever,
except as hereinbefore mentioned.

      AND FURTHERMORE, it the said Grantor, does by these presents bind itself
and its successors and assigns forever to WARRANT AND DEFEND the above granted
and bargained premises to it the said Grantee, its successors and assigns,
against all claims and demands whatsoever, except as hereinbefore mentioned.

      IN WETNESS WHEREOF, the Grantor has hereunto caused to be set its hand and
seal this 18th day of December

                                                                  [SEAL]

Signed, sealed and delivered                 F. I. P. CORPORATION
  in the presence of:

                                             By /s/ Stanley D Fisher
/s/ David M. Levin                              ------------------------
------------------                                  Its President
David M. Levin                                      Stanley D Fisher

/s/ [ILLEGIBLE]
-------------------
[ILLEGIBLE]

                                     - 4 -
<PAGE>

                                VO. 242 PAGE 223

STATE OF CONNECTICUT       )
                           ) ss.: Hartford, December 18, 1974
COUNTY OF HARTFORD         )

      On this 18th day of December, 1974, before me, David M. Levin, the
undersigned officer, personally appeared Stanley D. Fisher, who acknowledged
himself to be the President of F. I. P. CORPORATION, a corporation, and that he,
as such President being authorized so to do, executed the foregoing instrument
for the purposes therein contained, by signing the name of the corporation by
himself as

      In Witness Whereof, I hereunto set my hand.

                                             /s/ David M. Levin
                                       ------------------------------
                                               David M. Levin
                                     Commissioner of the Superior Court

[ILLEGIBLE]

                                     - 5 -

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