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                                                                   EXHIBIT 10.34

                         AVANT IMMUNOTHERAPEUTICS, INC.

                      1999 STOCK OPTION AND INCENTIVE PLAN

SECTION 1.  GENERAL PURPOSE OF THE PLAN; DEFINITIONS

     The name of the plan is the AVANT Immunotherapeutics, Inc. 1999 Stock
Option and Incentive Plan (the "Plan"). The purpose of the Plan is to encourage
and enable the officers, employees, Independent Directors and other key persons
(including consultants) of AVANT Immunotherapeutics, Inc. (the "Company") and
its Subsidiaries upon whose judgment, initiative and efforts the Company largely
depends for the successful conduct of its business to acquire a proprietary
interest in the Company. It is anticipated that providing such persons with a
direct stake in the Company's welfare will assure a closer identification of
their interests with those of the Company, thereby stimulating their efforts on
the Company's behalf and strengthening their desire to remain with the Company.

     The following terms shall be defined as set forth below:

     "ACT" means the Securities Exchange Act of 1934, as amended.

     "ADMINISTRATOR" is defined in Section 2(a).

     "AWARD" or "AWARDS," except where referring to a particular category of
grant under the Plan, shall include Incentive Stock Options, Non-Qualified Stock
Options, Stock Appreciation Rights, Deferred Stock Awards, Restricted Stock
Awards, Unrestricted Stock Awards, Performance Share Awards and Dividend
Equivalent Rights.

     "BOARD" means the Board of Directors of the Company.

     "CHANGE OF CONTROL" is defined in Section 17.

     "CODE" means the Internal Revenue Code of 1986, as amended, and any
successor Code, and related rules, regulations and interpretations.

     "COMMITTEE" means the Committee of the Board referred to in Section 2.

     "COVERED EMPLOYEE" means an employee who is a "Covered Employee" within the
meaning of Section 162(m) of the Code.

     "DEFERRED STOCK AWARD" means Awards granted pursuant to Section 8.

     "DIVIDEND EQUIVALENT RIGHT" means Awards granted pursuant to Section 12.

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     "EFFECTIVE DATE" means the date on which the Plan is approved by
stockholders as set forth in Section 19.

     "FAIR MARKET VALUE" of the Stock on any given date means the fair market
value of the Stock determined in good faith by the Administrator; provided,
however, that (i) if the Stock is admitted to quotation on the National
Association of Securities Dealers Automated Quotation System ("NASDAQ"), NASDAQ
National System or a national securities exchange, the determination shall be
made by reference to market quotations. If there are no market quotations for
such date, the determination shall be made by reference to the last date
preceding such date for which there are market quotations.

     "INCENTIVE STOCK OPTION" means any Stock Option designated and qualified as
an "incentive stock option" as defined in Section 422 of the Code.

     "INDEPENDENT DIRECTOR" means a member of the Board who is not also an
employee of the Company or any Subsidiary.

     "NON-QUALIFIED STOCK OPTION" means any Stock Option that is not an
Incentive Stock Option.

     "OPTION" or "STOCK OPTION" means any option to purchase shares of Stock
granted pursuant to Section 5.

     "PERFORMANCE SHARE AWARD" means Awards granted pursuant to Section 10.

     "PERFORMANCE CYCLE" means one or more periods of time, which may be of
varying and overlapping durations, as the Administrator may select, over which
the attainment of one or more performance criteria will be measured for the
purpose of determining a participant's right to and the payment of a Performance
Share Award, Restricted Stock Award or Deferred Stock Award.

     "RESTRICTED STOCK AWARD" means Awards granted pursuant to Section 7.

     "STOCK" means the Common Stock, par value $.01 per share, of the Company,
subject to adjustments pursuant to Section 3.

     "STOCK APPRECIATION RIGHT" means any Award granted pursuant to Section 6.

     "SUBSIDIARY" means any corporation or other entity (other than the Company)
in any unbroken chain of corporations or other entities beginning with the
Company if each of the corporations or entities (other than the last corporation
or entity in the unbroken chain) owns stock or other interests possessing 50
percent or more of the economic interest or the total combined voting power of
all classes of stock or other interests in one of the other corporations or
entities in the chain.

     "UNRESTRICTED STOCK AWARD" means any Award granted pursuant to Section 9.

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SECTION 2.  ADMINISTRATION OF PLAN; ADMINISTRATOR AUTHORITY TO SELECT
            PARTICIPANTS AND DETERMINE AWARDS

     (a)  COMMITTEE. The Plan shall be administered by either the Board or a
committee of not less than two Independent Directors (in either case, the
"Administrator").

     (b)  POWERS OF ADMINISTRATOR. The Administrator shall have the power and
authority to grant Awards consistent with the terms of the Plan, including the
power and authority:

          (i)     to select the individuals to whom Awards may from time to
time be granted;

          (ii)    to determine the time or times of grant, and the extent, if
     any, of Incentive Stock Options, Non-Qualified Stock Options, Stock
     Appreciation Rights, Restricted Stock Awards, Deferred Stock Awards,
     Unrestricted Stock Awards, Performance Share Awards and Dividend Equivalent
     Rights, or any combination of the foregoing, granted to any one or more
     participants;

          (iii)   to determine the number of shares of Stock to be covered by
     any Award;

          (iv)    to determine and modify from time to time the terms and
     conditions, including restrictions, not inconsistent with the terms of the
     Plan, of any Award, which terms and conditions may differ among individual
     Awards and participants, and to approve the form of written instruments
     evidencing the Awards;

          (v)     to accelerate the exercisability or vesting of all or any
     portion of any Award in circumstances involving a Change of Control or the
     death, disability or termination of employment of a Plan participant;

          (vi)    subject to the provisions of Section 5(a)(ii), to extend at
     any time the period in which Stock Options may be exercised; and

          (vii)   at any time to adopt, alter and repeal such rules, guidelines
     and practices for administration of the Plan and for its own acts and
     proceedings as it shall deem advisable; to interpret the terms and
     provisions of the Plan and any Award (including related written
     instruments); to make all determinations it deems advisable for the
     administration of the Plan; to decide all disputes arising in connection
     with the Plan; and to otherwise supervise the administration of the Plan.

     All decisions and interpretations of the Administrator shall be binding on
all persons, including the Company and Plan participants.

     (c)  DELEGATION OF AUTHORITY TO GRANT AWARDS. The Administrator, in its
discretion, may delegate to the Chief Executive Officer of the Company all or
part of the Administrator's authority and duties with respect to the granting of
Awards at Fair Market Value, to individuals who are not subject to the reporting
and other provisions of Section 16 of the Act or "covered employees" within the
meaning of Section 162(m) of the Code. Any such delegation by the Administrator
shall include a limitation as to the amount of Awards that may be granted during

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the period of the delegation and shall contain guidelines as to the
determination of the exercise price of any Stock Option or Stock Appreciation
Right, the conversion ratio or price of other Awards and the vesting criteria.
The Administrator may revoke or amend the terms of a delegation at any time but
such action shall not invalidate any prior actions of the Administrator's
delegate or delegates that were consistent with the terms of the Plan.

SECTION 3.  STOCK ISSUABLE UNDER THE PLAN; MERGERS; SUBSTITUTION

     (a)  STOCK ISSUABLE. The maximum number of shares of Stock reserved and
available for issuance under the Plan shall be 2,000,000 shares; provided that
not more than 500,000 shares shall be issued in the form of Unrestricted Stock
Awards, Restricted Stock Awards or Performance Share Awards. For purposes of
this limitation, the shares of Stock underlying any Awards granted under this
Plan or the Amended and Restated 1991 Stock Compensation Plan which are
forfeited, cancelled, reacquired by the Company, satisfied without the issuance
of Stock or otherwise terminated (other than by exercise) shall be added back to
the shares of Stock available for issuance under the Plan. Subject to such
overall limitation, shares of Stock may be issued up to such maximum number
pursuant to any type or types of Award; provided, however, that Stock Options or
Stock Appreciation Rights with respect to no more than 500,000 shares of Stock
may be granted to any one individual participant during any calendar year
period. The shares available for issuance under the Plan may be authorized but
unissued shares of Stock or shares of Stock reacquired by the Company and held
in its treasury.

     (b)  CHANGES IN STOCK. If, as a result of any reorganization,
recapitalization, reclassification, stock dividend, stock split, reverse stock
split or other similar change in the Company's capital stock, the outstanding
shares of Stock are increased or decreased or are exchanged for a different
number or kind of shares or other securities of the Company, or additional
shares or new or different shares or other securities of the Company or other
non-cash assets are distributed with respect to such shares of Stock or other
securities, the Administrator shall make an appropriate or proportionate
adjustment in (i) the maximum number of shares reserved for issuance under the
Plan, (ii) the number of Stock Options or Stock Appreciation Rights that can be
granted to any one individual participant, (iii) the number and kind of shares
or other securities subject to any then outstanding Awards under the Plan, and
(iv) the price for each share subject to any then outstanding Stock Options and
Stock Appreciation Rights under the Plan, without changing the aggregate
exercise price (i.e., the exercise price multiplied by the number of Stock
Options and Stock Appreciation Rights) as to which such Stock Options and Stock
Appreciation Rights remain exercisable. The adjustment by the Administrator
shall be final, binding and conclusive. No fractional shares of Stock shall be
issued under the Plan resulting from any such adjustment, but the Administrator
in its discretion may make a cash payment in lieu of fractional shares.

     The Administrator may also adjust the number of shares subject to
outstanding Awards and the exercise price and the terms of outstanding Awards to
take into consideration material changes in accounting practices or principles,
extraordinary dividends, acquisitions or dispositions of stock or property or
any other event if it is determined by the Administrator that such adjustment is
appropriate to avoid distortion in the operation of the Plan, provided that no
such adjustment shall be made in the case of an Incentive Stock Option, without
the consent of

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the participant, if it would constitute a modification, extension or renewal of
the Option within the meaning of Section 424(h) of the Code.

     (c)  MERGERS AND OTHER TRANSACTIONS. In the case of and subject to the
consummation of (i) the dissolution or liquidation of the Company, (ii) the sale
of all or substantially all of the assets of the Company on a consolidated basis
to an unrelated person or entity, (iii) a merger, reorganization or
consolidation in which the holders of the Company's outstanding voting power
immediately prior to such transaction do not own a majority of the outstanding
voting power of the surviving or resulting entity immediately upon completion of
such transaction, (iv) the sale of all of the Stock of the Company to an
unrelated person or entity or (v) any other transaction in which the owners of
the Company's outstanding voting power prior to such transaction do not own at
least a majority of the outstanding voting power of the relevant entity after
the transaction (in each case, a "Covered Transaction"), all Options and Stock
Appreciation Rights that are not exercisable shall become fully exercisable and
all other Awards with conditions and restrictions relating solely to the passage
of time and continued employment shall become fully vested, except as the
Administrator may otherwise specify with respect to particular Awards. Upon the
consummation of the Covered Transaction, the Plan and all outstanding Awards
granted hereunder shall terminate, unless provision is made in connection with
the Covered Transaction for the assumption of Awards heretofore granted, or the
substitution of such Awards with new Awards of the successor entity or parent
thereof, with appropriate adjustment as to the number and kind of shares and, if
appropriate, the per share exercise prices, as provided in Section 3(b) above.
In the event of such termination, each optionee shall be permitted, within a
specified period of time determined by the Administrator prior to consummation
of the Covered Transaction, to exercise all outstanding Options and Stock
Appreciation Rights held by such optionee, including those that are not then
exercisable, subject to the consummation of the Covered Transaction.

     (d)  SUBSTITUTE AWARDS. The Administrator may grant Awards under the Plan
in substitution for stock and stock based awards held by employees of another
corporation who become employees of the Company or a Subsidiary as the result of
a merger or consolidation of the employing corporation with the Company or a
Subsidiary or the acquisition by the Company or a Subsidiary of property or
stock of the employing corporation. The Administrator may direct that the
substitute awards be granted on such terms and conditions as the Administrator
considers appropriate in the circumstances. Any substitute Awards granted under
the Plan shall not count against the share limitation set forth in Section 3(a).

SECTION 4.  ELIGIBILITY

     Participants in the Plan will be such full or part-time officers and other
employees, Independent Directors and key persons (including consultants and
prospective employees) of the Company and its Subsidiaries as are selected from
time to time by the Administrator in its sole discretion.

SECTION 5.  STOCK OPTIONS

     Any Stock Option granted under the Plan shall be in such form as the
Administrator may from time to time approve.

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     Stock Options granted under the Plan may be either Incentive Stock Options
or Non-Qualified Stock Options. Incentive Stock Options may be granted only to
employees of the Company or any Subsidiary that is a "subsidiary corporation"
within the meaning of Section 424(f) of the Code. To the extent that any Option
does not qualify as an Incentive Stock Option, it shall be deemed a
Non-Qualified Stock Option.

     No Incentive Stock Option shall be granted under the Plan after May 8, 2012

     (a)  STOCK OPTIONS GRANTED TO EMPLOYEES AND KEY PERSONS. The Administrator
in its discretion may grant Stock Options to eligible employees and key persons
of the Company or any Subsidiary. Stock Options granted pursuant to this Section
5(a) shall be subject to the following terms and conditions and shall contain
such additional terms and conditions, not inconsistent with the terms of the
Plan, as the Administrator shall deem desirable. If the Administrator so
determines, Stock Options may be granted in lieu of cash compensation at the
participant's election, subject to such terms and conditions as the
Administrator may establish.

          (i)     EXERCISE PRICE. The exercise price per share for the Stock
     covered by a Stock Option granted pursuant to this Section 5(a) shall be
     determined by the Administrator at the time of grant but shall not be less
     than 100 percent of the Fair Market Value on the date of grant unless the
     Stock Option is granted in lieu of cash compensation. If an employee owns
     or is deemed to own (by reason of the attribution rules of Section 424(d)
     of the Code) more than 10 percent of the combined voting power of all
     classes of stock of the Company or any parent or subsidiary corporation and
     an Incentive Stock Option is granted to such employee, the option price of
     such Incentive Stock Option shall be not less than 110 percent of the Fair
     Market Value on the grant date.

          (ii)    OPTION TERM. The term of each Stock Option shall be fixed by
     the Administrator, but no Stock Option shall be exercisable more than ten
     years after the date the option is granted. If an employee owns or is
     deemed to own (by reason of the attribution rules of Section 424(d) of the
     Code) more than 10 percent of the combined voting power of all classes of
     stock of the Company or any parent or subsidiary corporation and an
     Incentive Stock Option is granted to such employee, the term of such option
     shall be no more than five years from the date of grant.

          (iii)   EXERCISABILITY; RIGHTS OF A STOCKHOLDER. Stock Options shall
     become exercisable at such time or times, whether or not in installments,
     as shall be determined by the Administrator at or after the grant date;
     provided, however, that Stock Options granted in lieu of compensation shall
     be exercisable in full as of the grant date. An optionee shall have the
     rights of a stockholder only as to shares acquired upon the exercise of a
     Stock Option and not as to unexercised Stock Options.

          (iv)    METHOD OF EXERCISE. Stock Options may be exercised in whole
     or in part, by giving written notice of exercise to the Company, specifying
     the number of shares to be purchased. Payment of the purchase price may be
     made by one or more of the following methods to the extent provided in the
     Option Award agreement:

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                  (A)  In cash, by certified or bank check or other instrument
          acceptable to the Administrator;

                  (B)  Through the delivery (or attestation to the ownership)
          of shares of Stock that have been purchased by the optionee on the
          open market or that have been beneficially owned by the optionee for
          at least six months and are not then subject to restrictions under any
          Company plan. Such surrendered shares shall be valued at Fair Market
          Value on the exercise date;

                  (C)  By the optionee delivering to the Company a properly
          executed exercise notice together with irrevocable instructions to a
          broker to promptly deliver to the Company cash or a check payable and
          acceptable to the Company for the purchase price; provided that in the
          event the optionee chooses to pay the purchase price as so provided,
          the optionee and the broker shall comply with such procedures and
          enter into such agreements of indemnity and other agreements as the
          Administrator shall prescribe as a condition of such payment
          procedure; or

                  (D)  By the optionee delivering to the Company a promissory
          note if the Board has expressly authorized the loan of funds to the
          optionee for the purpose of enabling or assisting the optionee to
          effect the exercise of his Stock Option; provided that at least so
          much of the exercise price as represents the par value of the Stock
          shall be paid other than with a promissory note.

     Payment instruments will be received subject to collection. The delivery of
     certificates representing the shares of Stock to be purchased pursuant to
     the exercise of a Stock Option will be contingent upon receipt from the
     optionee (or a purchaser acting in his stead in accordance with the
     provisions of the Stock Option) by the Company of the full purchase price
     for such shares and the fulfillment of any other requirements contained in
     the Stock Option or applicable provisions of laws. In the event an optionee
     chooses to pay the purchase price by previously-owned shares of Stock
     through the attestation method, the number of shares of Stock transferred
     to the optionee upon the exercise of the Stock Option shall be net of the
     number of shares attested to.

          (v)     ANNUAL LIMIT ON INCENTIVE STOCK OPTIONS. To the extent
     required for "incentive stock option" treatment under Section 422 of the
     Code, the aggregate Fair Market Value (determined as of the time of grant)
     of the shares of Stock with respect to which Incentive Stock Options
     granted under this Plan and any other plan of the Company or its parent and
     subsidiary corporations become exercisable for the first time by an
     optionee during any calendar year shall not exceed $100,000. To the extent
     that any Stock Option exceeds this limit, it shall constitute a
     Non-Qualified Stock Option.

     (b)  RELOAD OPTIONS. At the discretion of the Administrator, Options
granted under the Plan may include a "reload" feature pursuant to which an
optionee exercising an option by the delivery of a number of shares of Stock in
accordance with Section 5(a)(iv)(B) hereof would automatically be granted an
additional Option (with an exercise price equal to the Fair Market Value of the
Stock on the date the additional Option is granted and with such other terms as
the Administrator may provide) to purchase that number of shares of Stock equal
to the sum of (i)

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the number delivered to exercise the original Option and (ii) the number
withheld to satisfy tax liabilities, with an Option term equal to the remainder
of the original Option term unless the Administrator otherwise determines in the
Award agreement for the original Option grant.

     (c)  STOCK OPTIONS GRANTED TO INDEPENDENT DIRECTORS.

          (i)     AUTOMATIC GRANT OF OPTIONS.

                  (A)  Each Independent Director who is serving as Director of
          the Company on the fifth business day after each annual meeting of
          shareholders, beginning with the 1999 annual meeting, shall
          automatically be granted on such day a Non-Qualified Stock Option to
          acquire 10,000 shares of Stock.

                  (B)  The exercise price per share for the Stock covered by a
          Stock Option granted under this Section 5(c) shall be equal to the
          Fair Market Value of the Stock on the date the Stock Option is
          granted.

                  (C)  The Administrator, in its discretion, may grant
          additional Non-Qualified Stock Options to Independent Directors. Any
          such grant may vary among individual Independent Directors.

          (ii)    EXERCISE; TERMINATION.

                  (A)  Unless otherwise determined by the Administrator, an
          Option granted under Section 5(c) shall be exercisable after the first
          anniversary of the grant date. An Option issued under this Section
          5(c) shall not be exercisable after the expiration of ten years from
          the date of grant.

                  (B)  Options granted under this Section 5(c) may be exercised
          only by written notice to the Company specifying the number of shares
          to be purchased. Payment of the full purchase price of the shares to
          be purchased may be made by one or more of the methods specified in
          Section 5(a)(iv). An optionee shall have the rights of a stockholder
          only as to shares acquired upon the exercise of a Stock Option and not
          as to unexercised Stock Options.

     (d)  NON-TRANSFERABILITY OF OPTIONS. No Stock Option shall be transferable
by the optionee otherwise than by will or by the laws of descent and
distribution and all Stock Options shall be exercisable, during the optionee's
lifetime, only by the optionee, or by the optionee's legal representative or
guardian in the event of the optionee's incapacity. Notwithstanding the
foregoing, the Administrator, in its sole discretion, may provide in the Award
agreement regarding a given Option that the optionee may transfer his
Non-Qualified Stock Options to members of his immediate family, to trusts for
the benefit of such family members, or to partnerships in which such family
members are the only partners, provided that the transferee agrees in writing
with the Company to be bound by all of the terms and conditions of this Plan and
the applicable Option.

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SECTION 6.  STOCK APPRECIATION RIGHTS.

     (a)  NATURE OF STOCK APPRECIATION RIGHTS. A Stock Appreciation Right is an
Award entitling the recipient to receive an amount in cash or shares of Stock or
a combination thereof having a value equal to the excess of the Fair Market
Value of the Stock on the date of exercise over the exercise price of the Stock
Appreciation Right, which price shall not be less than 100 percent of the Fair
Market Value of the Stock on the date of grant (or more than the option exercise
price per share, if the Stock Appreciation Right was granted in tandem with a
Stock Option) multiplied by the number of shares of Stock with respect to which
the Stock Appreciation Right shall have been exercised, with the Administrator
having the right to determine the form of payment.

     (b)  GRANT AND EXERCISE OF STOCK APPRECIATION RIGHTS. Stock Appreciation
Rights may be granted by the Administrator in tandem with, or independently of,
any Stock Option granted pursuant to Section 5 of the Plan. In the case of a
Stock Appreciation Right granted in tandem with a Non-Qualified Stock Option,
such Stock Appreciation Right may be granted either at or after the time of the
grant of such Option. In the case of a Stock Appreciation Right granted in
tandem with an Incentive Stock Option, such Stock Appreciation Right may be
granted only at the time of the grant of the Option.

     A Stock Appreciation Right or applicable portion thereof granted in tandem
with a Stock Option shall terminate and no longer be exercisable upon the
termination or exercise of the related Option.

     (c)  TERMS AND CONDITIONS OF STOCK APPRECIATION RIGHTS. Stock Appreciation
Rights shall be subject to such terms and conditions as shall be determined from
time to time by the Administrator, subject to the following:

          (i)     Stock Appreciation Rights granted in tandem with Options shall
     be exercisable at such time or times and to the extent that the related
     Stock Options shall be exercisable.

          (ii)    Upon exercise of a Stock Appreciation Right, the applicable
     portion of any related Option shall be surrendered.

          (iii)   All Stock Appreciation Rights shall be exercisable during the
     participant's lifetime only by the participant or the participant's legal
     representative.

SECTION 7.  RESTRICTED STOCK AWARDS

     (a)  NATURE OF RESTRICTED STOCK AWARDS. A Restricted Stock Award is an
Award entitling the recipient to acquire, at par value or such other higher
purchase price determined by the Administrator, shares of Stock subject to such
restrictions and conditions as the Administrator may determine at the time of
grant ("Restricted Stock"). Conditions may be based on continuing employment (or
other business relationship) and/or achievement of pre-established performance
goals and objectives. The grant of a Restricted Stock Award is contingent on the
participant executing the Restricted Stock Award agreement. The terms and
conditions of each

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such agreement shall be determined by the Administrator, and such terms and
conditions may differ among individual Awards and participants.

     (b)  RIGHTS AS A STOCKHOLDER. Upon execution of a written instrument
setting forth the Restricted Stock Award and payment of any applicable purchase
price, a participant shall have the rights of a stockholder with respect to the
voting of the Restricted Stock, subject to such conditions contained in the
written instrument evidencing the Restricted Stock Award. Unless the
Administrator shall otherwise determine, certificates evidencing the Restricted
Stock shall remain in the possession of the Company until such Restricted Stock
is vested as provided in Section 7(d) below, and the participant shall be
required, as a condition of the grant, to deliver to the Company a stock power
endorsed in blank.

     (c)  RESTRICTIONS. Restricted Stock may not be sold, assigned, transferred,
pledged or otherwise encumbered or disposed of except as specifically provided
herein or in the Restricted Stock Award agreement. If a participant's employment
(or other business relationship) with the Company and its Subsidiaries
terminates for any reason, the Company shall have the right to repurchase
Restricted Stock that has not vested at the time of termination at its original
purchase price, from the participant or the participant's legal representative.

     (d)  VESTING OF RESTRICTED STOCK. The Administrator at the time of grant
shall specify the date or dates and/or the attainment of pre-established
performance goals, objectives and other conditions on which the
non-transferability of the Restricted Stock and the Company's right of
repurchase or forfeiture shall lapse. Subsequent to such date or dates and/or
the attainment of such pre-established performance goals, objectives and other
conditions, the shares on which all restrictions have lapsed shall no longer be
Restricted Stock and shall be deemed "vested." Except as may otherwise be
provided by the Administrator either in the Award agreement or, subject to
Section 15 below, in writing after the Award agreement is issued, a
participant's rights in any shares of Restricted Stock that have not vested
shall automatically terminate upon the participant's termination of employment
(or other business relationship) with the Company and its Subsidiaries and such
shares shall be subject to the Company's right of repurchase as provided in
Section 7(c) above.

     (e)  WAIVER, DEFERRAL AND REINVESTMENT OF DIVIDENDS. The Restricted Stock
Award agreement may require or permit the immediate payment, waiver, deferral or
investment of dividends paid on the Restricted Stock.

SECTION 8.  DEFERRED STOCK AWARDS

     (a)  NATURE OF DEFERRED STOCK AWARDS. A Deferred Stock Award is an Award of
phantom stock units to a participant, subject to restrictions and conditions as
the Administrator may determine at the time of grant. Conditions may be based on
continuing employment (or other business relationship) and/or achievement of
pre-established performance goals and objectives. The grant of a Deferred Stock
Award is contingent on the participant executing the Deferred Stock Award
agreement. The terms and conditions of each such agreement shall be determined
by the Administrator, and such terms and conditions may differ among individual
Awards and participants. At the end of the deferral period, the Deferred Stock
Award, to the extent vested, shall be paid to the participant in the form of
shares of Stock.

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     (b)  ELECTION TO RECEIVE DEFERRED STOCK AWARDS IN LIEU OF COMPENSATION. The
Administrator may, in its sole discretion, permit a participant to elect to
receive a portion of the cash compensation or Restricted Stock Award otherwise
due to such participant in the form of a Deferred Stock Award. Any such election
shall be made in writing and shall be delivered to the Company no later than the
date specified by the Administrator and in accordance with rules and procedures
established by the Administrator. The Administrator shall have the sole right to
determine whether and under what circumstances to permit such elections and to
impose such limitations and other terms and conditions thereon as the
Administrator deems appropriate.

     (c)  RIGHTS AS A STOCKHOLDER. During the deferral period, a participant
shall have no rights as a stockholder; provided, however, that the participant
may be credited with Dividend Equivalent Rights with respect to the phantom
stock units underlying his Deferred Stock Award, subject to such terms and
conditions as the Administrator may determine.

     (d)  RESTRICTIONS. A Deferred Stock Award may not be sold, assigned,
transferred, pledged or otherwise encumbered or disposed of during the deferral
period.

     (e)  TERMINATION. Except as may otherwise be provided by the Administrator
either in the Award agreement or, subject to Section 15 below, in writing after
the Award agreement is issued, a participant's right in all Deferred Stock
Awards that have not vested shall automatically terminate upon the participant's
termination of employment (or cessation of business relationship) with the
Company and its Subsidiaries for any reason.

SECTION 9.  UNRESTRICTED STOCK AWARDS

     GRANT OR SALE OF UNRESTRICTED STOCK. The Administrator may, in its sole
discretion, grant (or sell at par value or such higher purchase price determined
by the Administrator) an Unrestricted Stock Award to any participant pursuant to
which such participant may receive shares of Stock free of any restrictions
("Unrestricted Stock") under the Plan. Unrestricted Stock Awards may be granted
or sold as described in the preceding sentence in respect of past services or
other valid consideration, or in lieu of cash compensation due to such
participant.

SECTION 10. PERFORMANCE SHARE AWARDS

     (a)  NATURE OF PERFORMANCE SHARE AWARDS. A Performance Share Award is an
Award entitling the recipient to acquire shares of Stock upon the attainment of
specified performance goals. The Administrator may make Performance Share Awards
independent of or in connection with the granting of any other Award under the
Plan. The Administrator in its sole discretion shall determine whether and to
whom Performance Share Awards shall be made, the performance goals, the periods
during which performance is to be measured, and all other limitations and
conditions.

     (b)  RIGHTS AS A STOCKHOLDER. A participant receiving a Performance Share
Award shall have the rights of a stockholder only as to shares actually received
by the participant under the Plan and not with respect to shares subject to the
Award but not actually received by the participant. A participant shall be
entitled to receive a stock certificate evidencing the acquisition of shares of
Stock under a Performance Share Award only upon satisfaction of all

                                       11
<Page>

conditions specified in the Performance Share Award agreement (or in a
performance plan adopted by the Administrator).

     (c)  TERMINATION. Except as may otherwise be provided by the Administrator
either in the Award agreement or, subject to Section 15 below, in writing after
the Award agreement is issued, a participant's rights in all Performance Share
Awards shall automatically terminate upon the participant's termination of
employment (or cessation of business relationship) with the Company and its
Subsidiaries for any reason.

     (d)  ACCELERATION, WAIVER, ETC. At any time prior to the participant's
termination of employment (or other business relationship) by the Company and
its Subsidiaries, the Administrator may in its sole discretion accelerate, waive
or, subject to Section 15, amend any or all of the goals, restrictions or
conditions applicable to a Performance Share Award.

SECTION 11. PERFORMANCE-BASED AWARDS TO COVERED EMPLOYEES

     Notwithstanding anything to the contrary contained herein, if any
Restricted Stock Award, Deferred Stock Award or Performance Share Award granted
to a Covered Employee is intended to qualify as "Performance-based Compensation"
under Section 162(m) of the Code and the regulations promulgated thereunder (a
"Performance-based Award"), such Award shall comply with the provisions set
forth below:

     (a)  PERFORMANCE CRITERIA. The performance criteria used in performance
goals governing Performance-based Awards granted to Covered Employees may
include any or all of the following: (i) the Company's return on equity, assets,
capital or investment, (ii) pre-tax or after-tax profit levels of the Company or
any Subsidiary, a division, an operating unit or a business segment of the
Company, or any combination of the foregoing; (iii) cash flow, funds from
operations, year-end cash and equivalents balance or similar measure; (iv) total
shareholder return; (v) changes in the market price of the Stock; (vi) sales or
market share; (vii) earnings per share; (viii) partnerships, collaborations,
joint ventures, alliances and similar arrangements involving the Company; (ix)
mergers, acquisitions and business combinations of or by the Company; or (x) the
Company's rights to intellectual property and scientific discoveries.

     (b)  GRANT OF PERFORMANCE-BASED AWARDS. With respect to each
Performance-based Award granted to a Covered Employee, the Committee shall
select, within the first 90 days of a Performance Cycle (or, if shorter, within
the maximum period allowed under Section 162(m) of the Code) the performance
criteria for such grant, and the achievement targets with respect to each
performance criterion (including a threshold level of performance below which no
amount will become payable with respect to such Award). Each Performance-based
Award will specify the amount payable, or the formula for determining the amount
payable, upon achievement of the various applicable performance targets. The
performance criteria established by the Committee may be (but need not be)
different for each Performance Cycle and different goals may be applicable to
Performance-based Awards to different Covered Employees.

     (c)  PAYMENT OF PERFORMANCE-BASED AWARDS. Following the completion of a
Performance Cycle, the Committee shall meet to review and certify in writing
whether, and to what extent, the performance criteria for the Performance Cycle
have been achieved and, if so, to

                                       12
<Page>

also calculate and certify in writing the amount of the Performance-based Awards
earned for the Performance Cycle. The Committee shall then determine the actual
size of each Covered Employee's Performance-based Award, and, in doing so, may
reduce or eliminate the amount of the Performance-based Award for a Covered
Employee if, in its sole judgment, such reduction or elimination is appropriate.

     (d)  MAXIMUM AWARD PAYABLE. The maximum Performance-based Award payable to
any one Covered Employee under the Plan for a Performance Cycle is 250,000
Shares (subject to adjustment as provided in Section 3(b) hereof).

SECTION 12. DIVIDEND EQUIVALENT RIGHTS

     (a)  DIVIDEND EQUIVALENT RIGHTS. A Dividend Equivalent Right is an Award
entitling the recipient to receive credits based on cash dividends that would
have been paid on the shares of Stock specified in the Dividend Equivalent Right
(or other award to which it relates) if such shares had been issued to and held
by the recipient. A Dividend Equivalent Right may be granted hereunder to any
participant as a component of another Award or as a freestanding award. The
terms and conditions of Dividend Equivalent Rights shall be specified in the
grant. Dividend equivalents credited to the holder of a Dividend Equivalent
Right may be paid currently or may be deemed to be reinvested in additional
shares of Stock, which may thereafter accrue additional equivalents. Any such
reinvestment shall be at Fair Market Value on the date of reinvestment or such
other price as may then apply under a dividend reinvestment plan sponsored by
the Company, if any. Dividend Equivalent Rights may be settled in cash or shares
of Stock or a combination thereof, in a single installment or installments. A
Dividend Equivalent Right granted as a component of another Award may provide
that such Dividend Equivalent Right shall be settled upon exercise, settlement,
or payment of, or lapse of restrictions on, such other award, and that such
Dividend Equivalent Right shall expire or be forfeited or annulled under the
same conditions as such other award. A Dividend Equivalent Right granted as a
component of another Award may also contain terms and conditions different from
such other award.

     (b)  INTEREST EQUIVALENTS. Any Award under this Plan that is settled in
whole or in part in cash on a deferred basis may provide in the grant for
interest equivalents to be credited with respect to such cash payment. Interest
equivalents may be compounded and shall be paid upon such terms and conditions
as may be specified by the grant.

     (c)  TERMINATION. Except as may otherwise be provided by the Administrator
either in the Award agreement or, subject to Section 15 below, in writing after
the Award agreement is issued, a participant's rights in all Dividend Equivalent
Rights or interest equivalents shall automatically terminate upon the
participant's termination of employment (or cessation of business relationship)
with the Company and its Subsidiaries for any reason.

SECTION 13. TAX WITHHOLDING

     (a)  PAYMENT BY PARTICIPANT. Each participant shall, no later than the date
as of which the value of an Award or of any Stock or other amounts received
thereunder first becomes includable in the gross income of the participant for
Federal income tax purposes, pay to the

                                       13
<Page>

Company, or make arrangements satisfactory to the Administrator regarding
payment of, any Federal, state, or local taxes of any kind required by law to be
withheld with respect to such income. The Company and its Subsidiaries shall, to
the extent permitted by law, have the right to deduct any such taxes from any
payment of any kind otherwise due to the participant. The Company's obligation
to deliver stock certificates to any participant is subject to and conditioned
on tax obligations being satisfied by the participant.

     (b)  PAYMENT IN STOCK. Subject to approval by the Administrator, a
participant may elect to have such tax withholding obligation satisfied, in
whole or in part, by (i) authorizing the Company to withhold from shares of
Stock to be issued pursuant to any Award a number of shares with an aggregate
Fair Market Value (as of the date the withholding is effected) that would
satisfy the withholding amount due, or (ii) transferring to the Company shares
of Stock owned by the participant with an aggregate Fair Market Value (as of the
date the withholding is effected) that would satisfy the withholding amount due.

SECTION 14. TRANSFER, LEAVE OF ABSENCE, ETC.

     For purposes of the Plan, the following events shall not be deemed a
termination of employment:

     (a)  a transfer to the employment of the Company from a Subsidiary or from
the Company to a Subsidiary, or from one Subsidiary to another; or

     (b)  an approved leave of absence for military service or sickness, or for
any other purpose approved by the Company, if the employee's right to
re-employment is guaranteed either by a statute or by contract or under the
policy pursuant to which the leave of absence was granted or if the
Administrator otherwise so provides in writing.

SECTION 15. AMENDMENTS AND TERMINATION

     The Board may, at any time, amend or discontinue the Plan and the
Administrator may, at any time, amend or cancel any outstanding Award for the
purpose of satisfying changes in law or for any other lawful purpose, but no
such action shall (a) adversely affect rights under any outstanding Award
without the holder's consent or (b) without the prior approval of the Company's
stockholders, reduce the exercise price of or otherwise reprice, including
through replacement grants, any outstanding Stock Option or Stock Appreciation
Right. If and to the extent determined by the Administrator to be required by
the Code to ensure that Incentive Stock Options granted under the Plan are
qualified under Section 422 of the Code or to ensure that compensation earned
under Awards qualifies as performance-based compensation under Section 162(m) of
the Code, if and to the extent intended to so qualify, Plan amendments shall be
subject to approval by the Company stockholders entitled to vote at a meeting of
stockholders. Nothing in this Section 15 shall limit the Administrator's
authority to take any action permitted pursuant to Section 3(c).

SECTION 16. STATUS OF PLAN

     With respect to the portion of any Award that has not been exercised and
any payments in cash, Stock or other consideration not received by a
participant, a participant shall have no rights

                                       14
<Page>

greater than those of a general creditor of the Company unless the Administrator
shall otherwise expressly determine in connection with any Award or Awards. In
its sole discretion, the Administrator may authorize the creation of trusts or
other arrangements to meet the Company's obligations to deliver Stock or make
payments with respect to Awards hereunder, provided that the existence of such
trusts or other arrangements is consistent with the foregoing sentence.

SECTION 17. CHANGE OF CONTROL PROVISIONS

     Upon the occurrence of a Change of Control as defined in this Section 17:

     (a)  Except as otherwise provided in the applicable Award agreement, each
outstanding Stock Option, Stock Appreciation Right and Dividend Equivalent Right
shall automatically become fully exercisable.

     (b)  Except as otherwise provided in the applicable Award Agreement,
conditions and restrictions on each outstanding Restricted Stock Award, Deferred
Stock Award and Performance Share Award which relate solely to the passage of
time and continued employment will be removed. Performance or other conditions
(other than conditions and restrictions relating solely to the passage of time
and continued employment) will continue to apply unless otherwise provided in
the applicable Award Agreement.

     (c)  "Change of Control" shall mean the occurrence of any one of the
following events:

          (i)     any "PERSON," as such term is used in Sections 13(d) and
     14(d) of the Act (other than the Company, any of its Subsidiaries, or any
     trustee, fiduciary or other person or entity holding securities under any
     employee benefit plan or trust of the Company or any of its Subsidiaries),
     together with all "affiliates" and "associates" (as such terms are defined
     in Rule 12b-2 under the Act) of such person, shall become the "beneficial
     owner" (as such term is defined in Rule 13d-3 under the Act), directly or
     indirectly, of securities of the Company representing 25 percent or more of
     the combined voting power of the Company's then outstanding securities
     having the right to vote in an election of the Company's Board of Directors
     ("Voting Securities") (in such case other than as a result of an
     acquisition of securities directly from the Company); or

          (ii)    persons who, as of the Effective Date, constitute the
     Company's Board of Directors (the "Incumbent Directors") cease for any
     reason, including, without limitation, as a result of a tender offer, proxy
     contest, merger or similar transaction, to constitute at least a majority
     of the Board, provided that any person becoming a director of the Company
     subsequent to the Effective Date shall be considered an Incumbent Director
     if such person's election was approved by or such person was nominated for
     election by either (A) a vote of at least a majority of the Incumbent
     Directors or (B) a vote of at least a majority of the Incumbent Directors
     who are members of a nominating committee comprised, in the majority, of
     Incumbent Directors; but provided further, that any such person whose
     initial assumption of office is in connection with an actual or threatened
     election contest relating to the election of members of the Board of
     Directors or other actual or threatened solicitation of proxies or consents
     by or on behalf of a PERSON other

                                       15
<Page>

     than the Board, including by reason of agreement intended to avoid or
     settle any such actual or threatened contest or solicitation, shall not be
     considered an Incumbent Director; or

          (iii)   the stockholders of the Company shall approve (A) any
     consolidation or merger of the Company where the stockholders of the
     Company, immediately prior to the consolidation or merger, would not,
     immediately after the consolidation or merger, beneficially own (as such
     term is defined in Rule 13d-3 under the Act), directly or indirectly,
     shares representing in the aggregate more than 50 percent of the voting
     shares of the corporation issuing cash or securities in the consolidation
     or merger (or of its ultimate parent corporation, if any), (B) any sale,
     lease, exchange or other transfer (in one transaction or a series of
     transactions contemplated or arranged by any party as a single plan) of all
     or substantially all of the assets of the Company or (C) any plan or
     proposal for the liquidation or dissolution of the Company.

     Notwithstanding the foregoing, a "Change of Control" shall not be deemed to
have occurred for purposes of the foregoing clause (i) solely as the result of
an acquisition of securities by the Company which, by reducing the number of
shares of Voting Securities outstanding, increases the proportionate number of
shares of Voting Securities beneficially owned by any person to 25 percent or
more of the combined voting power of all then outstanding Voting Securities;
PROVIDED, HOWEVER, that if any person referred to in this sentence shall
thereafter become the beneficial owner of any additional shares of Voting
Securities (other than pursuant to a stock split, stock dividend, or similar
transaction or as a result of an acquisition of securities directly from the
Company), then a "CHANGE OF CONTROL" shall be deemed to have occurred for
purposes of the foregoing clause (i).

SECTION 18. GENERAL PROVISIONS

     (a)  NO DISTRIBUTION; COMPLIANCE WITH LEGAL REQUIREMENTS. The Administrator
may require each person acquiring Stock pursuant to an Award to represent to and
agree with the Company in writing that such person is acquiring the shares
without a view to distribution thereof.

     No shares of Stock shall be issued pursuant to an Award until all
applicable securities law and other legal and stock exchange or similar
requirements have been satisfied. The Administrator may require the placing of
such stop-orders and restrictive legends on certificates for Stock and Awards as
it deems appropriate.

     (b)  DELIVERY OF STOCK CERTIFICATES. Stock certificates to participants
under this Plan shall be deemed delivered for all purposes when the Company or a
stock transfer agent of the Company shall have mailed such certificates in the
United States mail, addressed to the participant, at the participant's last
known address on file with the Company.

     (c)  OTHER COMPENSATION ARRANGEMENTS; NO EMPLOYMENT RIGHTS. Nothing
contained in this Plan shall prevent the Board from adopting other or additional
compensation arrangements, including trusts, and such arrangements may be either
generally applicable or applicable only in specific cases. The adoption of this
Plan and the grant of Awards do not

                                       16
<Page>

confer upon any employee any right to continued employment with the Company or
any Subsidiary.

     (d)  TRADING POLICY RESTRICTIONS. Option exercises and other Awards under
the Plan shall be subject to such Company's insider trading policy, as in effect
from time to time.

SECTION 19. EFFECTIVE DATE OF PLAN

     This Plan shall become effective upon approval by the holders of a majority
of the votes cast at a meeting of stockholders at which a quorum is present.
Subject to such approval by the stockholders and to the requirement that no
Stock may be issued hereunder prior to such approval, Stock Options and other
Awards may be granted hereunder on and after adoption of this Plan by the Board.

     No Stock Options or other Awards shall be granted hereunder after May 8,
2012.

SECTION 20. GOVERNING LAW

     This Plan and all Awards and actions taken thereunder shall be governed by,
and construed in accordance with, the laws of the State of Delaware, applied
without regard to conflict of law principles.

DATE APPROVED BY BOARD OF DIRECTORS: March 18, 1999

DATE APPROVED BY STOCKHOLDERS: May 8, 1999

DATE FIRST AMENDED BY STOCKHOLDERS: May 8, 2002

                                       17<Page>
                                                                     EXHIBIT 4.8

                    HERITAGE PROPERTY INVESTMENT TRUST, INC.
                               535 BOYLSTON STREET
                                BOSTON, MA 02116

                          Dated as of February 7, 2003

Prudential Insurance Company of America
8 Campus Drive, 4th Floor
Parsippany, NJ 07054-4409
Attention: Robert Falzon

Ladies and Gentlemen:

     RE: WARRANTS

     Reference is hereby made to the (i) Warrant Agreement ("1999 WARRANT
AGREEMENT"), dated as of July 9, 1999, by and between The Prudential Insurance
Company of America ("Prudential"), and Heritage Property Investment Trust, Inc.
("Heritage"), pursuant to which Heritage issued to Prudential a warrant (the
"1999 WARRANT") to purchase 75,000 shares of common stock of Heritage, par value
$.001 per share ("COMMON STOCK"), and (ii) Warrant Agreement ("2000 WARRANT
AGREEMENT" and, together with the 1999 Warrant Agreement, the "WARRANT
AGREEMENTS"), dated as of September 18, 2000, by and between Prudential and
Heritage, pursuant to which Heritage issued to Prudential a warrant (the "2000
WARRANT" and, together with the 1999 Warrant, the "WARRANTS") to purchase
300,000 shares of Common Stock. Defined terms used herein but not defined herein
shall have the meanings given to such terms in the Warrant Agreements.

     In consideration of the mutual agreements contained herein and intending to
be legally bound hereby, the parties hereto agree that the Warrant Agreements
and the Warrants are hereby amended to change the Expiration Date of the
Warrants to April 29, 2007. All other terms and conditions of the Warrant
Agreements shall remain in full force and effect.

     If the foregoing correctly sets forth the understanding between us, please
so indicate on the enclosed signed copy of this Agreement in the space provided
below and return it to Heritage, whereupon this Agreement shall constitute a
binding agreement between us.

                                  Very truly yours,

                                  HERITAGE PROPERTY INVESTMENT TRUST, INC.

                                  By: /s/ Thomas C. Prendergast
                                      -----------------------------------------
                                      Name:  Thomas C. Prendergast
                                      Title: Chairman, President and
                                             Chief Executive Officer

AGREED TO AND ACCEPTED:
PRUDENTIAL INSURANCE COMPANY OF AMERICA

By: /s/ Robert M. Falzon
    ------------------------------
    Name:  Robert M. Falzon
    Title: Authorized Person

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