Document:

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                                                                     EXHIBIT 4.4

                                  IBASIS, INC.

                                 THIRD AMENDMENT
                                       TO
                            1997 STOCK INCENTIVE PLAN

         Effective as of December 12, 2000, but subject to the approval of the
stockholders of iBasis, Inc., a Delaware corporation ("iBasis"), the 1997 Stock
Incentive Plan of iBasis, be hereby amended as follows:

                  (1) The number "5,700,000" is deleted from the fourth line of
         Section 3(a) and hereby replaced with the number "9,000,000."<PAGE>

                                                                    Exhibit 10.2

                        NEOGENESIS PHARMACEUTICALS, INC.

                        2002 EMPLOYEE STOCK PURCHASE PLAN

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1.   Purpose..................................................................1

2.   Definitions.. ...........................................................1

3.   Eligibility..............................................................3

4.   Offering Periods.........................................................3

5.   Participation............................................................3

6.   Method of Payment of Contributions.......................................4

7.   Grant of Option..........................................................4

8.   Exercise of Option.......................................................5

9.   Delivery.................................................................5

10.  Voluntary Withdrawal; Termination of Employment..........................5

11.  Interest.................................................................6

12.  Stock....................................................................6

13.  Administration...........................................................7

14.  Designation of Beneficiary...............................................7

15.  Transferability..........................................................7

16.  Use of Funds.............................................................8

17.  Reports..................................................................8

18.  Adjustments Upon Changes in Capitalization; Corporate Transactions.......8

19.  Amendment or Termination.................................................9

20.  Notices..................................................................10

21.  Conditions to Issuance of Shares.........................................10

22.  Term of Plan; Effective Date.............................................10

<PAGE>

                        NEOGENESIS PHARMACEUTICALS, INC.

                        2002 EMPLOYEE STOCK PURCHASE PLAN

         The following constitute the provisions of the 2002 Employee Stock
Purchase Plan of NeoGenesis Pharmaceuticals, Inc.

1.       PURPOSE

         The purpose of the Plan is to provide employees of the Company and its
Designated Subsidiaries with an opportunity to purchase Common Stock of the
Company. It is the intention of the Company to have the Plan qualify as an
"Employee Stock Purchase Plan" under Section 423 of the Code. The provisions of
the Plan shall, accordingly, be construed so as to extend and limit
participation in a manner consistent with the requirements of that section of
the Code.

2.       DEFINITIONS

         2.1.     BOARD means the Board of Directors of the Company or a
committee named by the Board of Directors of the Company, pursuant to Section 13
hereof, to supervise and administer the Plan.

         2.2.     CODE means the Internal Revenue Code of 1986, as amended.

         2.3.     COMMON STOCK means the Common Stock, par value $.001 per
share, of the Company.

         2.4.     COMPANY means NeoGenesis Pharmaceuticals, Inc., a Delaware
corporation.

         2.5.     COMPENSATION means all regular straight time compensation
including commissions but shall not include payments for overtime, shift
premium, incentive compensation, incentive payments, bonuses and other irregular
or infrequent compensation or benefits.

         2.6.     CONTINUOUS STATUS AS AN EMPLOYEE means the absence of any
interruption or termination of service as an Employee. Continuous Status as an
Employee shall not be considered interrupted in the case of (i) sick leave; (ii)
military leave; (iii) any other leave of absence approved by the Company,
provided that such leave is for a period of not more than 90 days, unless
reemployment upon the expiration of such leave is guaranteed by contract or
statute, or unless provided otherwise pursuant to Company policy adopted from
time to time; or (iv) in the case of transfers between locations of the Company
or between the Company and its Designated Subsidiaries.

         2.7.     CONTRIBUTIONS means all amounts credited to the account of a
participant pursuant to the Plan.

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                                      -2-

         2.8.     CORPORATE TRANSACTION means a merger or consolidation of the
Company with and into another person or the sale, transfer, or other disposition
of all or substantially all of the Company's assets to one or more persons
(other than any wholly-owned subsidiary of the Company) in a single transaction
or series of related transactions.

         2.9.     DESIGNATED SUBSIDIARIES means the Subsidiaries which have been
designated by the Board from time to time in its sole discretion as eligible to
participate in the Plan.

         2.10.    EMPLOYEE means any person, including an Officer, who is
customarily employed for at least twenty (20) hours per week and more than five
(5) months in a calendar year by the Company or one of its Designated
Subsidiaries.

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

         2.12.    OFFERING COMMENCEMENT DATE means the first business day of
each Offering Period of the Plan.

         2.13.    OFFERING PERIOD means any of the periods, generally of six (6)
months duration, as set forth in Section 4.

         2.14.    OFFICER means a person who is an officer of the Company within
the meaning of Section 16 of the Exchange Act and the rules and regulations
promulgated thereunder.

         2.15.    OFFERING TERMINATION DATE means the last day of each Offering
Period of the Plan.

         2.16.    PLAN means this Employee Stock Purchase Plan.

         2.17.    PURCHASE PRICE means with respect to an Offering Period an
amount equal to 85% of the Fair Market Value (as defined in Section 7.2 below)
of a Share on the Offering Commencement Date or on the Offering Termination
Date, whichever is lower; provided, however, that in the event (i) of an
increase in the number of Shares available for issuance under the Plan as a
result of a stockholder-approved amendment to the Plan, and (ii) all or a
portion of such additional Shares are to be issued with respect to the Offering
Period underway at the time of such increase ("Additional Shares"), and (iii)
the Fair Market Value of a Share on the date of such increase (the "Approval
Date Fair Market Value") is higher than the Fair Market Value on the Offering
Commencement Date for such Offering Period, then in such instance the Purchase
Price with respect to Additional Shares shall be 85% of the Approval Date Fair
Market Value or the Fair Market Value of a Share on the Offering Termination
Date, whichever is lower.

         2.18.    SHARE means a share of Common Stock, as adjusted in accordance
with Section 18 of the Plan.

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                                      -3-

         2.19.    SUBSIDIARY means a corporation, domestic or foreign, of which
not less than 50% of the voting shares are held by the Company or a Subsidiary,
whether or not such corporation now exists or is hereafter organized or acquired
by the Company or a Subsidiary.

3.       ELIGIBILITY

         3.1.     Any person who is an Employee as of the Offering Commencement
Date of a given Offering Period shall be eligible to participate in such
Offering Period under the Plan, subject to the requirements of Section 5.1 and
the limitations imposed by Section 423(b) of the Code.

         3.2.     Any provisions of the Plan to the contrary notwithstanding, no
Employee shall be granted an option under the Plan (i) if, immediately after the
grant, such Employee (or any other person whose stock would be attributed to
such Employee pursuant to Section 424(d) of the Code) would own capital stock of
the Company and/or hold outstanding options to purchase stock possessing five
percent (5%) or more of the total combined voting power or value of all classes
of stock of the Company or of any Subsidiary of the Company, or (ii) if such
option would permit his or her rights to purchase stock under all employee stock
purchase plans (described in Section 423 of the Code) of the Company and its
Subsidiaries to accrue at a rate which exceeds twenty-five Thousand Dollars
($25,000) of the Fair Market Value (as defined in Section 7.2 below) of such
stock (determined at the time such option is granted) for each calendar year in
which such option is outstanding at any time.

4.       OFFERING PERIODS

         Each Offering Period will begin on January 1 and end on the next
following June 30, respectively. However, the first Offering Period shall
commence on July 1, 2002 and continue until December 31, 2002. At any time and
from time to time, the Board may change the duration and/or the frequency of
Offering Periods with respect to future Offering Periods or suspend operation of
the Plan with respect to Offering Periods not yet commenced.

5.       PARTICIPATION

         5.1.     An eligible Employee may become a participant in the Plan by
completing a subscription agreement on the form provided by the Company and
attached hereto as EXHIBIT A and filing it with the Company's payroll office
prior to the applicable Offering Commencement Date, unless a later time for
filing the subscription agreement is set by the Board for all eligible Employees
with respect to a given Offering Period. The subscription agreement shall set
forth the percentage of the participant's Compensation (subject to Section 6.1
below) to be paid as Contributions pursuant to the Plan.

         5.2.     Payroll deductions shall commence on the first payroll
following the Offering Commencement Date and shall end on the last payroll paid
on or prior to the

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                                      -4-

Offering Termination Date of the Offering Period to which the subscription
agreement is applicable, unless sooner terminated by the participant as provided
in Section 10.

6.       METHOD OF PAYMENT OF CONTRIBUTIONS

         6.1.     A participant shall elect to have payroll deductions made on
each payday during the Offering Period in an amount not less than one percent
(1%) and not more than twenty percent (20%) (or such other percentage as the
Board may establish from time to time before an Offering Commencement Date) of
such participant's Compensation on each payday during the Offering Period. All
payroll deductions made by a participant shall be credited to his or her account
under the Plan. A participant may not make any additional payments into such
account.

         6.2.     A participant may discontinue his or her participation in the
Plan as provided in Section 10 and, on one occasion only during each Offering
Period, may change the rate of his or her Contributions with respect to the
Offering Period by completing and filing with the Company a new subscription
agreement authorizing a change in the payroll deduction rate. Any such change in
rate shall be effective as of the beginning of the next calendar month following
the date of filing of the new subscription agreement, if the agreement is filed
at least ten (10) business days prior to such date and, if not, as of the
beginning of the next succeeding calendar month.

         6.3.     Notwithstanding the foregoing, to the extent necessary to
comply with Section 423(b)(8) of the Code and Section 3.2 herein, a
participant's payroll deductions may be decreased during any Offering Period
scheduled to end during the current calendar year to 0%. Payroll deductions
reduced to 0% in compliance with this Section 6.3 shall re-commence
automatically at the rate provided in such participant's subscription agreement
at the beginning of the first Offering Period which is scheduled to end in the
following calendar year, unless terminated by the participant as provided in
Section 10.

7.       GRANT OF OPTION

         7.1.     On the Offering Commencement Date of each Offering Period,
each eligible Employee participating in such Offering Period shall be granted an
option to purchase on the Offering Termination Date of that Offering Period a
number of Shares determined by dividing such Employee's Contributions
accumulated prior to such Offering Termination Date and retained in the
participant's account as of the Offering Termination Date by the applicable
Purchase Price. However, the maximum number of Shares an Employee may purchase
during each Offering Period shall be 1,700 Shares or such other maximum as the
Board may establish and announce as applicable to an Offering Period (subject to
any adjustment pursuant to Section 18 below), and provided further that such
purchase shall be subject to the limitations set forth in Sections 3.2 and 12.

         7.2.     The fair market value of the Company's Common Stock on a given
date (the "Fair Market Value") shall be determined by the Board in its
discretion based on the

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                                      -5-

closing sales price of the Common Stock for such date (or, in the event that the
Common Stock is not traded on such date, on the immediately preceding trading
date), as reported by the National Association of Securities Dealers Automated
Quotation ("Nasdaq") National Market or, if such price is not reported, the mean
of the bid and asked prices per share of the Common Stock as reported by Nasdaq
or, in the event the Common Stock is listed on a stock exchange, the Fair Market
value per share shall be the closing sales price on such exchange on such date
(or, in the event that the Common Stock is not traded on such date, on the
immediately preceding trading date), as reported in The Wall Street Journal.

8.       EXERCISE OF OPTION

         Unless a participant withdraws from the Plan as provided in Section 10,
his or her option for the purchase of Shares will be exercised automatically on
the Offering Termination Date of an Offering Period, and the maximum number of
full Shares subject to the option will be purchased at the applicable Purchase
Price with the accumulated Contributions in his or her account. No fractional
Shares shall be issued. The Shares purchased upon exercise of an option
hereunder shall be deemed to be transferred to the participant on the Offering
Termination Date. During his or her lifetime, a participant's option to purchase
Shares hereunder is exercisable only by him or her.

9.       DELIVERY

         As promptly as practicable after each Offering Termination Date of each
Offering Period, the Company shall arrange the delivery to each participant, as
appropriate, of a certificate representing the Shares purchased upon exercise of
his or her option. Any payroll deductions accumulated in a participant's account
which are not sufficient to purchase a full Share shall be retained in the
participant's account for the subsequent Offering Period, subject to earlier
withdrawal by the participant as provided in Section 10 below. Any other amounts
left over in a participant's account after an Offering Termination Date shall be
returned to the participant.

10.      VOLUNTARY WITHDRAWAL; TERMINATION OF EMPLOYMENT

         10.1.    A participant may withdraw all but not less than all of the
Contributions credited to his or her account under the Plan at any time prior to
each Offering Termination Date by giving written notice to the Company on the
form attached hereto as EXHIBIT B. All of the participant's Contributions
credited to his or her account will be paid to him or her promptly after receipt
of his or her notice of withdrawal and his or her option for the current period
will be automatically terminated, and no further Contributions for the purchase
of Shares will be made during the Offering Period.

         10.2.    Upon termination of the participant's Continuous Status as an
Employee prior to the Offering Termination Date of an Offering Period for any
reason, including retirement or death, the Contributions credited to his or her
account will be returned to him or her or, in the case of his or her death, to
the person or persons entitled thereto under Section 14, and his or her option
will be automatically terminated.

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                                      -6-

         10.3.    In the event an Employee fails to remain in Continuous Status
as an Employee of the Company for at least twenty (20) hours per week during the
Offering Period in which the employee is a participant, he or she will be deemed
to have elected to withdraw from the Plan and the Contributions credited to his
or her account will be returned to him or her and his or her option terminated.

         10.4.    A participant's withdrawal during an Offering Period will not
have any effect upon his or her eligibility to participate in a succeeding
Offering Period or in any similar plan which may hereafter be adopted by the
Company.

11.      INTEREST

         No interest shall accrue on the Contributions of a participant in the
Plan.

12.      STOCK

         12.1.    Subject to adjustment as provided in Section 18, the maximum
number of Shares which shall be made available for sale under the Plan shall be
500,000 Shares plus an automatic annual increase on January 1, 2003 and each
January 1 thereafter equal to the lesser of (i) two percent (2%) of the Shares
outstanding on the last day of the immediately preceding fiscal year, and (ii)
such number as the Board may determine. Notwithstanding the foregoing, and
subject to adjustment in accordance with Section 18 no more than an aggregate of
1,000,000 Shares may be issued pursuant to this Plan. If the Board determines
that, on a given Offering Termination Date, the number of shares with respect to
which options are to be exercised may exceed (i) the number of shares of Common
Stock that were available for sale under the Plan on the Offering Commencement
Date, or (ii) the number of shares available for sale under the Plan on such
Offering Termination Date, the Board may in its sole discretion provide that the
Company shall make a pro rata allocation of the Shares available for purchase on
such Offering Commencement Date or Offering Termination Date, as applicable, in
as uniform a manner as shall be practicable and as it shall determine in its
sole discretion to be equitable among all participants exercising options to
purchase Common Stock on such Offering Termination Date. The Company may make
pro rata allocation of the Shares available on the Offering Commencement Date of
the applicable Offering Period pursuant to the preceding sentence,
notwithstanding any authorization of additional Shares for issuance under the
Plan by the Company's stockholders subsequent to such Offering Commencement
Date.

         12.2.    The participant shall have no interest or voting right in
Shares covered by his or her option until such option has been exercised.

         12.3.    Shares to be delivered to a participant under the Plan will be
registered in the name of the participant or in the name of the participant and
his or her spouse, as directed by the participant.

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                                      -7-

13.      ADMINISTRATION

         The Board, or a committee named by the Board, shall supervise and
administer the Plan and shall have full power to adopt, amend and rescind any
rules deemed desirable and appropriate for the administration of the Plan and
not inconsistent with the Plan, to construe and interpret the Plan, and to make
all other determinations necessary or advisable for the administration of the
Plan. The Board's determinations made in good faith on matters referred to in
this Plan shall be final, binding and conclusive on all persons having or
claiming any interest under this Plan.

14.      DESIGNATION OF BENEFICIARY

         14.1.    A participant may file a written designation of a beneficiary
who is to receive any Shares and cash, if any, from the participant's account
under the Plan in the event of such participant's death subsequent to the end of
an Offering Period but prior to delivery to him or her of such Shares and cash.
In addition, a participant may file a written designation of a beneficiary who
is to receive any cash from the participant's account under the Plan in the
event of such participant's death prior to the Offering Termination Date of an
Offering Period.

         14.2.    Such designation of beneficiary may be changed by the
participant at any time by written notice. In the event of the death of a
participant and in the absence of a beneficiary validly designated under the
Plan who is living at the time of such participant's death, the Company shall
deliver such Shares and/or cash to the executor or administrator of the estate
of the participant, or if no such executor or administrator has been appointed
(to the knowledge of the Company), the Company, in its discretion, may deliver
such Shares and/or cash to the spouse or to any one or more dependents or
relatives of the participant, or if no spouse, dependent or relative is known to
the Company, then to such other person as the Company may designate.

15.      TRANSFERABILITY

         Neither Contributions credited to a participant's account nor any
rights with regard to the exercise of an option or to receive Shares under the
Plan may be assigned, transferred, pledged or otherwise disposed of in any way
(other than by will, the laws of descent and distribution, or as provided in
Section 14) by the participant. Any such attempt at assignment, transfer, pledge
or other disposition shall be without effect, except that the Company may treat
such act as an election to withdraw funds in accordance with Section 10.

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                                      -8-

16.      USE OF FUNDS

         All Contributions received or held by the Company under the Plan may be
used by the Company for any corporate purpose, and the Company shall not be
obligated to segregate such Contributions from its other assets.

17.      REPORTS

         Individual accounts will be maintained for each participant in the
Plan. Statements of account will be given to participating Employees at least
annually, which statements will set forth the amounts of Contributions, the
Purchase Price per Share, the number of Shares purchased and the remaining cash
balance, if any.

18.      ADJUSTMENTS UPON CHANGES IN CAPITALIZATION; CORPORATE TRANSACTIONS

         18.1.    ADJUSTMENT. Subject to any required action by the stockholders
of the Company, the number of shares covered by each option under the Plan which
has not yet been exercised and the number of Shares which have been authorized
for issuance under the Plan but have not yet been placed under option
(collectively, the "Reserves"), as well as the maximum number of shares of
Common Stock which may be purchased by a participant in an Offering Period, the
number of shares of Common Stock set forth in Section 12.1 above, and the price
per Share covered by each option under the Plan which has not yet been
exercised, shall be proportionately adjusted for any increase or decrease in the
number of issued Shares resulting from a stock split, reverse stock split, stock
dividend, combination or reclassification of the Common Stock (including any
such change in the number of Shares effected in connection with a change in
domicile of the Company), or any other increase or decrease in the number of
Shares effected without receipt of consideration by the Company; provided
however that conversion of any convertible securities of the Company shall not
be deemed to have been "effected without receipt of consideration." Such
adjustment shall be made by the Board, whose determination in that respect shall
be final, binding and conclusive.

         18.2.    CORPORATE TRANSACTIONS. In the event of a dissolution or
liquidation of the Company, the Offering Period then in progress will terminate
immediately prior to the consummation of such action, unless otherwise provided
by the Board. In the event of a Corporate Transaction, each option outstanding
under the Plan shall be assumed or an equivalent option shall be substituted by
the successor corporation or a parent or Subsidiary of such successor
corporation. In the event that the successor corporation refuses to assume or
substitute for outstanding options, the Offering Period then in progress shall
be shortened and a new Offering Termination Date shall be set (the "New Offering
Termination Date"), as of which date the Offering Period then in progress will
terminate. The New Offering Termination Date shall be on or before the date of
consummation of the transaction and the Board shall notify each participant in
writing, at least ten (10) days prior to the New Offering Termination Date, that
the Offering Termination Date for his or her option has been changed to the New
Offering Termination Date and that his or her option will be exercised
automatically on the New

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                                      -9-

Offering Termination Date, unless prior to such date he or she has withdrawn
from the Offering Period as provided in Section 10. For purposes of this Section
18, an option granted under the Plan shall be deemed to be assumed, without
limitation, if, at the time of issuance of the stock or other consideration upon
a Corporate Transaction, each holder of an option under the Plan would be
entitled to receive upon exercise of the option the same number and kind of
shares of stock or the same amount of property, cash or securities as such
holder would have been entitled to receive upon the occurrence of the
transaction if the holder had been, immediately prior to the transaction, the
holder of the number of Shares covered by the option at such time (after giving
effect to any adjustments in the number of Shares covered by the option as
provided for in this Section 18); provided however that if the consideration
received in the transaction is not solely common stock of the successor
corporation or its parent (as defined in Section 424(e) of the Code), the Board
may, with the consent of the successor corporation, provide for the
consideration to be received upon exercise of the option to be solely common
stock of the successor corporation or its parent equal in Fair Market Value to
the per Share consideration received by holders of Common Stock in the
transaction.

         The Board may, if it so determines in the exercise of its sole
discretion, also make provision for adjusting the Reserves, as well as the price
per Share of Common Stock covered by each outstanding option, in the event that
the Company effects one or more reorganizations, recapitalizations, rights
offerings or other increases or reductions of Shares of its outstanding Common
Stock, and in the event of the Company's being consolidated with or merged into
any other corporation.

19.      AMENDMENT OR TERMINATION

         19.1.    The Board may at any time and for any reason terminate or
amend the Plan. Except as provided in Section 18, no such termination of the
Plan may affect options previously granted, provided that the Plan or an
Offering Period may be terminated by the Board on an Offering Termination Date
or by the Board's setting a new Offering Termination Date with respect to an
Offering Period then in progress if the Board determines that termination of the
Plan and/or the Offering Period is in the best interests of the Company and its
stockholders or if continuation of the Plan and/or the Offering Period would
cause the Company to incur adverse accounting charges as a result of the Plan.
Except as provided in Section 18 and in this Section 19, no amendment to the
Plan shall make any change in any option previously granted which adversely
affects the rights of any participant.

         19.2.    Without stockholder consent and without regard to whether any
participant rights may be considered to have been adversely affected, the Board
(or its committee) shall be entitled to change the Offering Periods, limit the
frequency and/or number of changes in the amount withheld during an Offering
Period, establish the exchange ratio applicable to amounts withheld in a
currency other than U.S. dollars, permit payroll withholding in excess of the
amount designated by a participant in order to adjust for delays or mistakes in
the Company's processing of properly completed withholding elections, establish
reasonable waiting and adjustment periods and/or

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                                      -10-

accounting and crediting procedures to ensure that amounts applied toward the
purchase of Common Stock for each participant properly correspond with amounts
withheld from the participant's Compensation, and establish such other
limitations or procedures as the Board determines in its sole discretion
advisable which are consistent with the Plan.

20.      NOTICES

         All notices or other communications by a participant to the Company
under or in connection with the Plan shall be deemed to have been duly given
when received in the form specified by the Company at the location, or by the
person, designated by the Company for the receipt thereof.

21.      CONDITIONS TO ISSUANCE OF SHARES

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

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

22.      TERM OF PLAN; EFFECTIVE DATE

         The Plan shall become effective upon on the closing of the Company's
initial public offering of Common Stock pursuant to a registration statement
filed with the Securities and Exchange Commission. The Plan shall continue in
effect for a term of ten (10) years after the closing of such initial public
offering unless sooner terminated under Section 19.

<PAGE>

                                                                       EXHIBIT A

                        NEOGENESIS PHARMACEUTICALS, INC.

                        2002 EMPLOYEE STOCK PURCHASE PLAN

                             SUBSCRIPTION AGREEMENT

                                                             New Election
                                                                          ------

                                                       Change of Election
                                                                          ------

          1.     I, __________________, hereby elect to participate in the
NeoGenesis Pharmaceuticals, Inc. 2002 Employee Stock Purchase Plan (the "Plan")
for the Offering Period __________, _____ to ______________, _____, and
subscribe to purchase shares of the Company's Common Stock in accordance with
this Subscription Agreement and the Plan.

         2.      I elect to have Contributions in the amount of _____% of my
Compensation, as those terms are defined in the Plan, applied to this purchase.
I understand that this amount must not be less than 1% and not more than 20% of
my Compensation during the Offering Period. (Please note that no fractional
percentages are permitted).

         3.      I hereby authorize payroll deductions from each paycheck
during the Offering Period at the rate stated in Item 2 of this Subscription
Agreement. I understand that all payroll deductions made by me shall be credited
to my account under the Plan and that I may not make any additional payments
into such account. I understand that all payments made by me shall be
accumulated, without interest or earnings, for the purchase of shares of Common
Stock at the applicable purchase price determined in accordance with the Plan. I
further understand that, except as otherwise set forth in the Plan, shares will
be purchased for me automatically on the Offering Termination Date of each
Offering Period unless I otherwise withdraw from the Plan by giving written
notice to the Company for such purpose.

         4.      I understand that I may discontinue at any time prior to the
Purchase Date my participation in the Plan as provided in Section 10 of the
Plan. I also understand that I can increase or decrease the rate of my
Contributions on one occasion only during any Offering Period by completing and
filing a new Subscription Agreement with such increase or decrease taking effect
as of the beginning of the calendar month following the date of filing of the
new Subscription Agreement, if filed at least ten (10) business days prior to
the beginning of such month. Further, I may change the rate of deductions for
future Offering Periods by filing a new Subscription Agreement, and any such
change will be effective as of the beginning of the next Offering Period. In
addition, I acknowledge that, unless I discontinue my participation in the Plan
as provided in Section 10 of the Plan, my election will continue to be effective
for each successive Offering Period.

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                                      -2-

         5.      I have received a copy of the complete NeoGenesis
Pharmaceuticals, Inc. 2002 Employee Stock Purchase Plan. I understand that my
participation in the Plan is in all respects subject to the terms of the Plan.

         6.      Shares purchased for me under the Plan should be issued in the
name(s) of (name of employee or employee and spouse only):

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

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

         7.      In the event of my death, I hereby designate the following as
my beneficiary(ies) to receive all payments and shares due to me under the Plan:

NAME: (Please print)
                           -----------------------------------------------------
                                 (First)           (Middle)         (Last)

----------------------                          --------------------------------
(Relationship)                                  (Address)

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

         8.      I understand that if I dispose of any shares received by me
pursuant to the Plan within 2 years after the Offering Commencement Date (the
first day of the Offering Period during which I purchased such shares) or within
1 year after the Offering Termination Date, I will be treated for federal income
tax purposes as having received ordinary compensation income at the time of such
disposition in an amount equal to the excess of the fair market value of the
shares on the Offering Termination Date over the price which I paid for the
shares, regardless of whether I disposed of the shares at a price less than
their fair market value at the Offering Termination Date. The remainder of the
gain or loss, if any, recognized on such disposition will be treated as capital
gain or loss.

         I hereby agree to notify the Company in writing within 30 days after
the date of any such disposition, and I will make adequate provision for
federal, state or other tax withholding obligations, if any, which arise upon
the disposition of the Common Stock. The Company may, but will not be obligated
to, withhold from my compensation the amount necessary to meet any applicable
withholding obligation including any withholding necessary to make available to
the Company any tax deductions or benefits attributable to the sale or early
disposition of Common Stock by me.

         9.      If I dispose of such shares at any time after expiration of
the 2-year and 1-year holding periods, I understand that I will be treated for
federal income tax purposes as having received compensation income only to the
extent of an amount equal to the lesser of (1) the excess of the fair market
value of the shares at the time of such disposition over the purchase price
which I paid for the shares under the option, or (2) 15% of the fair market
value of the shares on the Offering Commencement Date. The

<PAGE>

                                      -3-

remainder of the gain or loss, if any, recognized on such disposition will be
treated as capital gain or loss.

         I understand that this tax summary is only a summary and is subject to
change. I further understand that I should consult a tax advisor concerning
certain tax implications of the purchase and sale of stock under the Plan.

         10.      I hereby agree to be bound by the terms of the Plan. The
effectiveness of this Subscription Agreement is dependent upon my eligibility to
participate in the Plan.

SIGNATURE:
           ------------------------------------------

SOCIAL SECURITY #:
                   ----------------------------------

DATE:
       ----------------------------------------------

<PAGE>

                                                                       EXHIBIT B

                        NEOGENESIS PHARMACEUTICALS, INC.

                        2002 EMPLOYEE STOCK PURCHASE PLAN

                              NOTICE OF WITHDRAWAL

         I, _____________, hereby elect to withdraw my participation in the
NeoGenesis Pharmaceuticals, Inc. 2002 Employee Stock Purchase Plan (the "Plan")
for the Offering Period that began on _________________, ________. This
withdrawal covers all Contributions credited to my account and is effective on
the date designated below.

         I understand that all Contributions credited to my account will be paid
to me within ten (10) business days of receipt by the Company of this Notice of
Withdrawal and that my option for the current period will automatically
terminate, and that no further Contributions for the purchase of shares can be
made by me during the Offering Period.

         The undersigned further understands and agrees that he or she shall be
eligible to participate in succeeding Offering Periods only by delivering to the
Company a new Subscription Agreement.

Dated:
       -----------------------------     ---------------------------------------
                                                   Signature of Employee

                                         ---------------------------------------
                                                   Social Security Number

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