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                                                                   Exhibit 10.4

                              ACTIVBIOTICS, INC.
                         2006 DIRECTOR OPTION PLAN

1.   PURPOSE

     This Plan is intended to promote the recruiting and retention of highly
qualified Eligible Directors, to strengthen the commonality of interest between
directors and stockholders by encouraging ownership of Common Stock of the
Company by Eligible Directors, and to provide additional incentives for Eligible
Directors to promote the success of the Company's business. The Plan is NOT
intended to be an incentive stock option plan within the meaning of Section 422
of the Code. None of the Options granted hereunder will be "incentive stock
options" within the meaning of Section 422 of the Code.

2.   DEFINITIONS

     As used in the Plan the following terms shall have the respective meanings
set out below, unless the context clearly requires otherwise:

     2.1. "Accelerate", "Accelerated", and "Acceleration", when used with
respect to an Option, means that as of the time of reference such Option will
become exercisable with respect to some or all of the shares of Common Stock for
which it was not then otherwise exercisable by its terms.

     2.2. "Acquiring Person" means, with respect to any Transaction or any
acquisition described in clause (ii) of the definition of Change of Control, the
surviving or acquiring person or entity in connection with such Transaction or
acquisition, as the case may be, provided that if such surviving or acquiring
person or entity is controlled, directly or indirectly, by any other person or
entity (an "Ultimate Parent Entity") that is not itself controlled by any entity
or person that is not a natural person, the term "Acquiring Person" shall mean
such Ultimate Parent Entity.

     2.3. "Affiliate" means, with respect to any person or entity, any other
person or entity controlling, controlled by or under common control with the
first person or entity.

     2.4. "Applicable Voting Control Percentage" means twenty percent (20%).

     2.5. "Beneficial Ownership" has the meaning ascribed to such term in Rule
13d-3, or any successor rule thereto, promulgated by the Securities and Exchange
Commission pursuant to the Exchange Act.

     2.6. "Board" means the Company's board of directors.

     2.7. "Change of Control" means (i) the closing of any Sale of the Company
Transaction or (ii) the direct or indirect acquisition, in a single transaction
or a series of related transactions, by any person or Group (other than the
Company or a Controlled Affiliate of the Company) of Beneficial Ownership of
previously outstanding shares of capital stock of the Company if (A) immediately
after such acquisition, such person or Group, together with their respective
Affiliates, shall own or hold shares of capital stock of the Company possessing
at least the Applicable Voting Control Percentage of the total voting power of
the outstanding capital

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stock of the Company and (B) immediately prior to such acquisition, such person
or Group, together with their respective Affiliates, did not own or hold shares
of capital stock of the Company possessing at least the Applicable Voting
Control Percentage of the total voting power of the outstanding capital stock of
the Company. Notwithstanding anything expressed or implied in the foregoing
provisions of this definition to the contrary, any direct or indirect
acquisition referred to in clause (ii) above in this definition shall not be
treated as a Change of Control if, at any time prior to or after such direct or
indirect acquisition, a majority of the members of the board of directors of the
Company as constituted immediately prior to such direct or indirect acquisition
consent in writing to exclude such direct or indirect acquisition from the scope
of this definition.

     2.8. "Code" means the Internal Revenue Code of 1986, as amended from time
to time, or any successor statute thereto, and any regulations issued from time
to time thereunder.

     2.9. "Controlled Affiliate" means, with respect to any person or entity,
any other person or entity that is controlled by such person or entity.

     2.10. "Committee" means any committee of the Board delegated responsibility
by the Board for the administration of the Plan, as provided in Section 5 of the
Plan. For any period during which no such committee is in existence, "Committee"
shall mean the Board and all authority and responsibility assigned the Committee
under the Plan shall be exercised, if at all, by the Board.

     2.11. "Common Stock" means common stock, par value $0.01 per share, of the
Company.

     2.12. "Company" means ActivBiotics, Inc., a corporation organized under the
laws of the State of Delaware.

     2.13. "Eligible Director" means a director of one or more of the Company
and its Subsidiaries who is not also an employee or officer of one or more of
the Company and its Subsidiaries.

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

     2.15. "Grant Date" means the date as of which an Option is granted, as
determined under Section 7.1 or Section 7.2, as applicable.

     2.16. "Group" has the meaning ascribed to such term in Section 13(d)(3) of
the Exchange Act or any successor section thereto.

     2.17. "Holder" means, with respect to any Option, (a) the Optionee to whom
such Option shall have been initially granted under the Plan, or (b) any
transferee of such Option to whom such Option shall have been transferred in
accordance with the provisions set forth herein..

     2.18. "Market Value" means the value of a share of Common Stock on a
particular date determined by such methods or procedures as may be established
by the Committee. Unless otherwise determined by the Committee, the Market Value
of Common Stock as of any date is the closing price for the Common Stock as
reported on the NASDAQ Global Market (or on any other national securities
exchange on which the Common Stock is then listed) for that date or, if

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no closing price is reported for that date, the closing price on the next
preceding date for which a closing price was reported.

     2.19. "Option" means an option granted under the Plan to purchase shares of
Common Stock.

     2.20. "Option Agreement" means an agreement between the Company and the
Holder of an Option, setting forth the terms and conditions of the Option.

     2.21. "Optionee" means an Eligible Director to whom an Option shall have
been granted under the Plan.

     2.22. "Plan" means this 2006 Director Option Plan of the Company, as
amended and in effect from time to time.

     2.23. "Sale of the Company Transaction" means any Transaction in which the
stockholders of the Company immediately prior to such Transaction, together with
any and all of such stockholders' Affiliates, do not own or hold, immediately
after consummation of such Transaction, shares of capital stock of the Acquiring
Person in connection with such Transaction possessing at least a majority of the
total voting power of the outstanding capital stock of such Acquiring Person.

     2.24. "Securities Act" means the Securities Act of 1933, as amended.

     2.25. "Transaction" means any merger or consolidation of the Company with
or into another person or entity or the sale or transfer of all or substantially
all of the assets of the Company, in each case in a single transaction or in a
series of related transactions.

3.   TERM OF THE PLAN

     Unless the Plan shall have been earlier terminated by the Board, Options
may be granted under this Plan at any time in the period commencing upon the
effectiveness of the Plan in accordance with the provisions of Section 17 hereof
and ending immediately prior to the tenth anniversary of the adoption of the
Plan by the Board. Options granted pursuant to the Plan within such period shall
not expire solely by reason of the termination of the Plan.

4.   STOCK SUBJECT TO THE PLAN

     Subject to the provisions of Section 8 of the Plan, at no time shall the
number of shares of Common Stock issued pursuant to or subject to outstanding
Options granted under the Plan exceed the sum of (a) 100,000 shares of Common
Stock plus (b) an additional 50,000 shares on each of January 1, 2007 and
January 1, 2008, and an additional number of shares on each January 1 thereafter
(beginning with January 1, 2009) equal to the lesser of (i) 0.6% of the
fully-diluted capitalization of the Company as of such date (including for this
purpose all outstanding options, warrants and other rights to acquire, whether
directly or indirectly, the Common Stock of the Company, whether vested or not),
and (ii) 100,000 shares of Common Stock; PROVIDED, HOWEVER, that the Board may,
at any time and on any one or more occasions, take action to waive the annual
increase set forth in clause (b), in whole or in part. For purposes of applying
the foregoing limitation, (a) if any Option expires, terminates, or is cancelled
for any reason without having been exercised in full, the shares not purchased
by the Optionee (or the Holder of such


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Option) shall again be available for Options thereafter to be granted under the
Plan, and (b) if any Option is exercised by delivering previously owned shares
in payment of the exercise price therefor, only the net number of shares, that
is, the number of shares issued minus the number received by the Company in
payment of the exercise price, shall be considered to have been issued pursuant
to an Option granted under the Plan. Shares of Common Stock issued pursuant to
the Plan may be either authorized but unissued shares or shares held by the
Company in its treasury.

5.   ADMINISTRATION

     The Plan shall be administered by the Committee; PROVIDED, HOWEVER, that at
any time and on any one or more occasions the Board may itself exercise any of
the powers and responsibilities assigned the Committee under the Plan and when
so acting shall have the benefit of all of the provisions of the Plan pertaining
to the Committee's exercise of its authorities hereunder. Subject to the
provisions of the Plan, the Committee shall have complete authority to interpret
the Plan, to prescribe, amend and rescind rules and regulations relating to it,
to determine the terms and provisions of the respective Option Agreements (which
need not be identical), and to make all other determinations necessary or
advisable for the administration of the Plan. The Committee'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 the Plan or
an Option made pursuant hereto.

6.   AUTHORIZATION AND ELIGIBILITY

     Only Eligible Directors shall be granted Options under the Plan. Each grant
of an Option shall be subject to all applicable terms and conditions of the Plan
(including but not limited to any specific terms and conditions set forth in the
Section 7 below), and such other terms and conditions, not inconsistent with the
terms of the Plan, as the Committee may prescribe. No prospective holder of an
Option shall have any rights with respect to such Option, unless and until such
holder has executed an agreement evidencing the Option, delivered a fully
executed copy thereof to the Company, and otherwise complied with the applicable
terms and conditions of such Option.

7.   SPECIFIC TERMS OF OPTIONS

     7.1. Directors Elected For First Time. After the Plan's effectiveness as
set forth in Section 17, each Eligible Director who is elected or appointed to
the Board during the term of the Plan (whether elected at an annual or special
stockholders' meeting or appointed by action of the Board), and who was not
immediately prior to such election or appointment already a member of the Board,
shall automatically be granted, on the date of such meeting or other appointment
or election, an Option to purchase (a) 5,000 shares of Common Stock (subject to
adjustment as set forth in Section 8) or (b) such other greater or smaller
number of shares of Common Stock as the Board shall have set by resolution of
the Board at or prior to the date of the appointment or election of such
Eligible Director (unless such resolution of the Board shall provide that such
Eligible Director shall not receive an Option under this Section 7.1, in which
case such Eligible Director shall not be granted any Option under this Section
7.1); PROVIDED, HOWEVER, that if such Eligible Director is not elected to the
Board at an annual stockholders' meeting, then the number of shares of Common
Stock subject to the Option granted or to be granted to such Eligible Director
pursuant to this Section 7.1 shall be equal to (A) the product of (i) the number
of shares of Common Stock to which such Option would be subject under this
Section 7.1 if such Eligible


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Director had been elected to the Board at the last annual meeting of
stockholders, if any, that occurred during the term of the Plan and (ii) a
fraction, the numerator of which shall be equal to twelve (12) minus the number
of thirty (30) day periods elapsed since the last annual meeting of
stockholders, if any, that occurred during the term of the Plan (provided that
in no event shall such numerator be less than zero), and the denominator of
which is twelve (12), or (B) such other greater or smaller number of shares of
Common Stock as the Board shall have set by resolution of the Board at or prior
to the date of the appointment or election of such Eligible Director (unless
such resolution shall provide that such Eligible Director shall not receive an
Option under this Section 7.1, in which case such Eligible Director shall not be
granted any Option under this Section 7.1). Subject to the provisions of this
Section 7.1 or Section 9 hereof. Subject to Section 9, grants of Options under
this Section 7.1 occur automatically without any action being required of the
Optionee, the Committee, the Board, the Company or any other person, entity or
body.

     7.2. Annual Grants. After the Plan's effectiveness as set forth in Section
17 and subject to the provisions set forth below in this Section 7.2, on the
date of each annual meeting of stockholders of the Company, commencing with the
2007 annual meeting of stockholders, each Eligible Director who continues to be
a director of the Company as of the close of business on the date of such annual
meeting of stockholders shall be granted an Option as of the close of business
on such date, to purchase 2,500 shares of Common Stock (subject to adjustment as
set forth in Section 8) or such other greater or smaller number of shares of
Common Stock as the Board shall have set by resolution of the Board prior to the
date of such annual meeting of stockholders (unless such resolution shall
provide that such Eligible Director shall not receive an Option under this
Section 7.2 at such annual meeting of stockholders, in which case such Eligible
Director shall not be granted any Option under this Section 7.2 as of the close
of business on the date of such annual meeting). Notwithstanding the foregoing
provisions of this Section 7.2, no Eligible Director shall be granted any Option
pursuant to this Section 7.2 as of the close of business on the date of any
annual meeting of stockholders if on such date such Eligible Director is granted
an Option pursuant to Section 7.1 hereof. Subject to the provisions of this
Section 7.2 or Section 9 hereof, grants of Options under this Section 7.2 shall
occur automatically without any action being required of the Optionee, the
Committee, the Board, the Company or any other person, entity or body.

     7.3. Certain Terms of Option; Exercise Price. Each Option granted to an
Optionee under this Section 7 shall have an exercise price equal to 100% of the
Market Value of the Stock on the applicable Grant Date. No Option granted
pursuant to this Plan is intended to qualify as an incentive stock option within
the meaning of Section 422 of the Code. The grants shall be evidenced by Option
Agreements containing provisions that are in all respects consistent with this
Section 7. All of such Option Agreements shall contain identical terms and
conditions, except as otherwise required or permitted by this Section 7.

     7.4. Option Period. The option period for each Option granted pursuant to
this Plan shall be ten (10) years from the Grant Date of such Option.

     7.5. Exercisability. Subject to Section 7.6 below, each Option granted to
an Eligible Director shall be exercisable as follows: (a) with respect to grants
made pursuant to Section 7.1, one hundred percent (100%) of the shares of Common
Stock underlying such Option, on the date of grant and (b) with respect to
grants made pursuant to Section 7.2, one hundred percent (100%) of the shares of
Common Stock underlying such Option, on the first anniversary of the date of
grant. In the case of an Option not otherwise immediately exercisable in full,
the Committee may Accelerate such Option in whole or in part at any time.


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     7.6. Effect of Termination of Board Member Relationship. Unless the
Committee at any time shall provide otherwise with respect to any Option, if an
Optionee ceases to be a director of the Company and its Affiliates for any
reason or no reason (whether voluntarily or involuntarily, including as a result
of death), any outstanding Option initially granted to such Optionee, whether
then held by such Optionee or any other Holder, shall cease to be exercisable in
any respect not later than ninety (90) days following that event and, for the
period it remains exercisable following that event, shall be exercisable only to
the extent exercisable at the date of that event.

     7.7. Transferability. Except as otherwise provided in this Section 7.7,
Options shall not be transferable, and no Option or interest therein may be
sold, transferred, pledged, assigned, or otherwise alienated or hypothecated,
other than by will or by the laws of descent and distribution (subject always to
the provisions of Section 7.6 hereof). Except as otherwise provided in this
Section 7.7, all of a Holder's rights in any Option may be exercised only during
the life of such Holder and only by such Holder or such Holder's legal
representative. However, the applicable Option Agreement or the Committee (at or
after the grant of an Option), may provide that an Option may be transferred by
the applicable Holder to a family member; PROVIDED, HOWEVER, that any such
transfer is without payment of any consideration whatsoever and that no transfer
of an Option shall be valid unless first approved by the Committee, acting in
its sole discretion, unless such transfer is permitted under the applicable
Option Agreement. For this purpose, "family member" means any child, stepchild,
grandchild, parent, stepparent, spouse, former spouse, sibling, niece, nephew,
mother-in-law, father-in-law, son-in-law, daughter-in-law, brother-in-law, or
sister-in-law, including adoptive relationships, any person sharing the
applicable Holder's household (other than a tenant or employee), a trust in
which the foregoing persons and/or the applicable Holder have more than fifty
percent (50%) of the beneficial interests, a foundation in which the foregoing
persons and/or the applicable Holder control the management of assets, and any
other entity in which these persons and/or the applicable Holder own more than
fifty percent (50%) of the voting interests. The Committee may at any time or
from time to time delegate to one or more officers of the Company the authority
to permit transfers of Options to third parties pursuant to this Section 7.7,
which authorization shall be exercised by such officer or officers in accordance
with guidelines established by the Committee at any time and from time to time.
The restrictions on transferability set forth in this Section 7.7, shall in no
way preclude any Holder from effecting "cashless" exercises of an Option
pursuant to the terms of the Plan.

     7.8. Method of Exercise. An Option may be exercised by the Holder of such
Option by giving written notice, in the manner provided in Section 15,
specifying the number of shares of Common Stock with respect to which the Option
is then being exercised. The notice shall be accompanied by payment in the form
of cash or check payable to the order of the Company in an amount equal to the
exercise price of the shares of Common Stock to be purchased or, subject in each
instance to the Committee's approval, acting in its sole discretion and subject
to such conditions, if any, as the Committee may deem necessary to comply with
applicable laws, rules and regulations and to avoid adverse accounting effects
to the Company, by delivery to the Company of shares of Common Stock having a
Market Value equal to the exercise price of the shares to be purchased. No
Holder shall be permitted to effect payment of any amount of the exercise price
of the shares of Common Stock to be purchased by executing and delivering to the
Company a promissory note. If the Common Stock is traded on an established
market, payment of any exercise price may also be made through and under the
terms and conditions of any formal cashless exercise program authorized by the
Company entailing the sale of the Common Stock subject to any Option in a
brokered transaction (other than to the Company). Receipt by the Company of such
notice and payment in any authorized or combination of authorized means shall


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constitute the exercise of the Option. Within thirty (30) days thereafter but
subject to the remaining provisions of the Plan, the Company shall deliver or
cause to be delivered to the Holder or his agent a certificate or certificates
for the number of shares then being purchased. Such shares shall be fully paid
and nonassessable. Notwithstanding any of the foregoing provisions in this
subsection 7.8 to the contrary, (A) no Option shall be considered to have been
exercised unless and until all of the provisions governing such exercise
specified in the Plan and in the relevant Option Agreement shall have been duly
complied with; and (B) the obligation of the Company to issue any shares upon
exercise of an Option is subject to the provisions of Section 9.1 hereof and to
compliance by the Holder with all of the provisions of the Plan and the relevant
Option Agreement.

     7.9. Rights Pending Exercise. No person holding an Option shall be deemed
for any purpose to be a stockholder of the Company with respect to any of the
shares of Common Stock issuable pursuant to his Option, except to the extent
that the Option shall have been exercised with respect thereto and, in addition,
a certificate shall have been issued therefor and delivered to such holder or
his agent.

     7.10. Grants to Optionee's Outside the United States. The Committee may
modify the terms of any Option under the Plan granted to an Optionee who is, at
the time of grant or during the term of the Option, resident or primarily
employed outside of the United States in any manner deemed by the Committee to
be necessary or appropriate in order that such Option shall conform to laws,
regulations, and customs of the country in which such Optionee is then resident
or primarily employed, or so that the value and other benefits of the Option to
such Optionee, as affected by foreign tax laws and other restrictions applicable
as a result of such Optionee's residence or employment abroad, shall be
comparable to the value of such Option to an Optionee who is resident or
primarily employed in the United States. An Option may be modified under this
Section 7.10 in a manner that is inconsistent with the express terms of the
Plan, so long as such modifications will not contravene any applicable law or
regulation. The Committee may establish supplements to, or amendments,
restatements, or alternative versions of the Plan for the purpose of granting
and administrating any such modified Option. No such modification, supplement,
amendment, restatement or alternative version may increase the share limit of
Section 4.

8.   ADJUSTMENT PROVISIONS

     8.1. Adjustment for Corporate Actions. All of the share numbers set forth
in the Plan reflect the capital structure of the Company immediately after the
closing of the initial public offering of the Company's Common Stock. Subject to
the provisions of Section 8.2, if subsequent to such date the outstanding shares
of Common Stock (or any other securities covered by the Plan by reason of the
prior application of this Section) are increased, decreased, or exchanged for a
different number or kind of shares or other securities, or if additional shares
or new or different shares or other securities are distributed with respect to
such shares of Common Stock or other securities, through merger, consolidation,
sale of all or substantially all the property of the Company, reorganization,
recapitalization, reclassification, stock dividend, stock split, reverse stock
split, or other distribution with respect to such shares of Common Stock, or
other securities, an appropriate and proportionate adjustment will be made in
(i) the maximum numbers and kinds of shares provided in Section 4, (ii) the
numbers and kinds of shares or other securities subject to the then outstanding
Options, and (iii) the exercise price for each share or other unit of any other
securities subject to then outstanding Options (without change in the aggregate
purchase price as to which such Options remain exercisable).


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     8.2. Change of Control. Subject to the applicable provisions of the Option
Agreement, in the event of a Change of Control, the Committee shall have the
discretion, exercisable in advance of, at the time of, or (except to the extent
otherwise provided below) at any time after, the Change of Control, to provide
for any or all of the following (subject to and upon such terms as the Committee
may deem appropriate): (A) the Acceleration, in whole or in part, of any or all
outstanding Options (including Options that are assumed or substituted pursuant
to clause (B) below) that are not exercisable in full at the time the Change of
Control, such Acceleration to become effective at the time of the Change of
Control, or at such time following the Change of Control that the initial
grantee of the Option ceases to be a director, or at such other time or times as
the Committee shall determine; (B) the assumption of outstanding Options, or the
substitution of outstanding Options with equivalent options, by the acquiring or
succeeding corporation or entity (or an affiliate thereof); or (C) the
termination of all Options (other than Options that are assumed or substituted
pursuant to clause (B) above) that remain outstanding at the time of the
consummation of the Change of Control, PROVIDED THAT, the Committee shall have
made the determination to effect such termination prior to the consummation of
the Change of Control and the Committee shall have given, or caused to be given,
to all Optionees written notice of such potential termination at least five
business days prior to the consummation of the Change of Control, and PROVIDED,
FURTHER, THAT, if the Committee shall have determined in its sole and absolute
discretion that the Corporation make payment or provide consideration to the
holders of such terminated Options on account of such termination, which payment
or consideration shall be on such terms and conditions as the Committee shall
have determined (and which could consist of, in the Committee's sole and
absolute discretion, payment to the applicable Optionee or Optionees of an
amount of cash equal to the difference between the Market Value of the shares of
Common Stock for which the Option is then exercisable and the aggregate exercise
price for such shares under the Option), then the Corporation shall be required
to make such payment or provide such consideration in accordance with the terms
and conditions so determined by the Committee; otherwise the Corporation shall
not be required to make any payment or provide any consideration in connection
with, or as a result of, the termination of Options pursuant to the foregoing
provisions of this clause (C). The provisions of this Section 8.2 shall not be
construed as to limit or restrict in any way the Committee's general authority
under Sections 7.5 hereof to Accelerate Options in whole or in part at any time.
Each outstanding Option that is assumed in connection with a Change of Control,
or is otherwise to continue in effect subsequent to a Change of Control, will be
appropriately adjusted, immediately after the Change of Control, as to the
number and class of securities and the price at which it may be exercised in
accordance with Section 8.1.

     8.3. Dissolution or Liquidation. Upon dissolution or liquidation of the
Company, each outstanding Option shall terminate, but the Optionee (if at the
time he or she is a board member of the Company or any of its Affiliates) shall
have the right, immediately prior to such dissolution or liquidation, to
exercise the Option to the extent exercisable on the date of such dissolution or
liquidation.

     8.4. Related Matters. Any adjustment in Options made pursuant to this
Section 8 shall be determined and made, if at all, by the Committee and shall
include any correlative modification of terms, including of Option exercise
prices, rates of vesting or exercisability which the Committee may deem
necessary or appropriate so as to ensure that the rights of the Holders in their
respective Options are not substantially diminished nor enlarged as a result of
the adjustment and corporate action other than as expressly contemplated in this
Section 8. No fraction of a share shall be purchasable or deliverable upon
exercise, but in the event any adjustment hereunder of the number of shares
covered by an Option shall cause such number to include a


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fraction of a share, such number of shares shall be adjusted to the nearest
smaller whole number of shares. No adjustment of an Option exercise price per
share pursuant to this Section 8 shall result in an exercise price which is less
than the par value of the Common Stock.

9.   SETTLEMENT OF OPTIONS

     9.1. Violation of Law. Notwithstanding any other provision of the Plan or
the relevant Option Agreement, if, at any time, in the reasonable opinion of the
Company, the issuance of shares of Common Stock covered by an Option may
constitute a violation of law, then the Company may delay such issuance and the
delivery of a certificate for such shares until (i) approval shall have been
obtained from such governmental agencies, other than the Securities and Exchange
Commission, as may be required under any applicable law, rule, or regulation and
(ii) in the case where such issuance would constitute a violation of a law
administered by or a regulation of the Securities and Exchange Commission, one
of the following conditions shall have been satisfied:

          (a) the shares are at the time of the issue of such shares effectively
registered under the Securities Act; or

          (b) the Company shall have determined, on such basis as it deems
appropriate (including an opinion of counsel in form and substance satisfactory
to the Company) that the sale, transfer, assignment, pledge, encumbrance or
other disposition of such shares or such beneficial interest, as the case may
be, does not require registration under the Securities Act or any applicable
state securities laws.

     9.2. Corporate Restrictions on Rights in Stock. Any Common Stock to be
issued pursuant to Options granted under the Plan shall be subject to all
restrictions upon the transfer thereof which may be now or hereafter imposed by
the Certificate of Incorporation and the By-laws of the Company, each as amended
and in effect from time to time. Whenever Common Stock is to be issued pursuant
to an Option, if the Committee so directs at the time of grant (or, if such
Option is an Option, at any time prior to the exercise thereof), the Company
shall be under no obligation, notwithstanding any other provision of the Plan or
the relevant Option Agreement to the contrary, to issue such shares until such
time, if ever, as the recipient of the Option (and any person who exercises any
Option, in whole or in part), shall have become a party to and bound by any
agreement that the Committee shall require in its sole discretion. In addition,
any Common Stock to be issued pursuant to Options granted under the Plan shall
be subject to all stop-transfer orders and other restrictions as the Committee
may deem advisable under the rules, regulations and other requirements of any
stock exchange upon which the Common Stock is then listed, and any applicable
federal or state securities laws, and the Committee may cause a legend or
legends to be put on any such certificates to make appropriate reference to such
restrictions.

     9.3. Investment Representations. The Company shall be under no obligation
to issue any shares covered by an Option unless the shares to be issued pursuant
to Options granted under the Plan have been effectively registered under the
Securities Act or the Holder shall have made such written representations to the
Company (upon which the Company believes it may reasonably rely) as the Company
may deem necessary or appropriate for purposes of confirming that the issuance
of such shares will be exempt from the registration requirements of that Act and
any applicable state securities laws and otherwise in compliance with all
applicable laws, rules and regulations, including but not limited to that the
Holder is acquiring shares for his or her own


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account for the purpose of investment and not with a view to, or for sale in
connection with, the distribution of any such shares.

     9.4. Registration. If the Company shall deem it necessary or desirable to
register under the Securities Act or other applicable statutes any shares of
Common Stock issued or to be issued pursuant to Options granted under the Plan,
or to qualify any such shares of Common Stock for exemption from the Securities
Act or other applicable statutes, then the Company shall take such action at its
own expense. The Company may require from each recipient of an Option, or each
holder of shares of Common Stock acquired pursuant to the Plan, such information
in writing for use in any registration statement, prospectus, preliminary
prospectus or offering circular as is reasonably necessary for such purpose and
may require reasonable indemnity to the Company and its officers and directors
from such holder against all losses, claims, damage and liabilities arising from
such use of the information so furnished and caused by any untrue statement of
any material fact therein or caused by the omission to state a material fact
required to be stated therein or necessary to make the statements therein not
misleading in the light of the circumstances under which they were made.

     9.5. Lock-Up. Without the prior written consent of the Company or the
managing underwriter in any public offering of shares of Common Stock, no Holder
shall sell, make any short sale of, loan, grant any option for the purchase of,
pledge or otherwise encumber, or otherwise dispose of, any shares of Common
Stock during the one hundred-eighty (180) day period commencing on the effective
date of the registration statement relating to any underwritten public offering
of securities of the Company. The foregoing restrictions are intended and shall
be construed so as to preclude any Holder from engaging in any hedging or other
transaction that is designed to or reasonably could be expected to lead to or
result in, a sale or disposition of any shares of Common Stock during such
period even if such shares of Common Stock are or would be disposed of by
someone other than such Holder. Such prohibited hedging or other transactions
would include, without limitation, any short sale (whether or not against the
box) or any purchase, sale or grant of any right (including without limitation
any put or call option) with respect to any shares of Common Stock or with
respect to any security that includes, relates to, or derives any significant
part of its value from any shares of Common Stock. Without limiting the
generality and applicability of the foregoing provisions of this Section 9.5,
if, in connection with any underwritten public offering of securities of the
Company, the managing underwriter of such offering requires that the Company's
directors and officers enter into a lock-up agreement then (a) each Holder
(regardless of whether or not such Holder has complied or complies with the
provisions of clause (b) below) shall be bound by, and shall be deemed to have
agreed to, the same lock-up terms as those to which the Company's directors and
officers are required to adhere; and (b) at the request of the Company or such
managing underwriter, each Holders shall execute and deliver a lock-up agreement
in form and substance equivalent to that which is required to be executed by the
Company's directors and officers.

     9.6. Placement of Legends; Stop Orders; Etc. Each share of Common Stock to
be issued pursuant to Options granted under the Plan may bear a reference to the
investment representations made in accordance with Section 9.3 in addition to
any other applicable restrictions under the Plan, the terms of the Option and,
if applicable, under any agreement between the Company and the Optionee and/or
Holder, and to the fact that no registration statement has been filed with the
Securities and Exchange Commission in respect to such shares of Common Stock.
All certificates for shares of Common Stock or other securities delivered under
the Plan shall be subject to such stock transfer orders and other restrictions
as the Committee may deem advisable under the rules, regulations, and other
requirements of any stock


                                       10
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exchange upon which the Common Stock is then listed, and any applicable federal
or state securities law, and the Committee may cause a legend or legends to be
placed on any such certificates to make appropriate reference to such
restrictions.

     9.7. Tax Withholding. Whenever shares of Common Stock are issued or to be
issued pursuant to Options granted under the Plan, the Company shall have the
right to require the recipient to remit to the Company an amount sufficient to
satisfy federal, state, local or other withholding tax requirements if, when,
and to the extent required by law (whether so required to secure for the Company
an otherwise available tax deduction or otherwise) prior to the delivery of any
certificate or certificates for such shares. The obligations of the Company
under the Plan shall be conditional on satisfaction of all such withholding
obligations and the Company 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
recipient of an Option. However, in such cases Holders may elect, subject to the
approval of the Committee, acting in its sole discretion, to satisfy an
applicable withholding requirement, in whole or in part, by having the Company
withhold shares to satisfy their tax obligations. Holders may only elect to have
shares of Common Stock withheld having a Market Value on the date the tax is to
be determined equal to the minimum statutory total tax which could be imposed on
the transaction. All elections shall be irrevocable, made in writing, signed by
the Holder, and shall be subject to any restrictions or limitations that the
Committee deems appropriate.

10.  RESERVATION OF STOCK

     The Company shall at all times during the term of the Plan and any
outstanding Options granted hereunder reserve or otherwise keep available such
number of shares of Common Stock as will be sufficient to satisfy the
requirements of the Plan (if then in effect) and such Options and shall pay all
fees and expenses necessarily incurred by the Company in connection therewith.

11.  NO SPECIAL SERVICE RIGHTS

     Nothing contained in the Plan or in any Option Agreement shall confer upon
any recipient of an Option any right with respect to any consulting or Board
member relationship or other association with the Company (or any Affiliate), or
interfere in any way with the right of the Company (or any Affiliate), subject
to the terms of any separate agreement or provision of law or corporate articles
or by-laws to the contrary, at any time to terminate Board member or to increase
or decrease, or otherwise adjust, the other terms and conditions of the
recipient Board member relationship or other association with the Company and
its Affiliates.

12.  NONEXCLUSIVITY OF THE PLAN

     Neither the adoption of the Plan by the Board nor the submission of the
Plan to the stockholders of the Company shall be construed as creating any
limitations on the power of the Board to adopt such other incentive arrangements
as it may deem desirable, including without limitation, the granting of stock
options and restricted stock other than under the Plan, and such arrangements
may be either applicable generally or only in specific cases.

13.  TERMINATION AND AMENDMENT OF THE PLAN

     The Board may at any time terminate the Plan or make such amendments or
modifications of the Plan as it shall deem advisable. In the event of the
termination of the Plan,


                                       11
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the terms of the Plan shall survive any such termination with respect to any
Option that is outstanding on the date of such termination, unless the holder of
such Option agrees in writing to terminate such Option or to terminate all or
any of the provisions of the Plan that apply to such Option. Unless the Board
otherwise expressly provides, any amendment or modification of the Plan shall
affect the terms of any Option outstanding on the date of such amendment or
modification as well as the terms of any Option made prior to, or from and
after, the date of such amendment or modification; PROVIDED, HOWEVER, that,
except to the extent otherwise provided in the last sentence of this paragraph,
(i) no amendment or modification of the Plan shall apply to any Option that is
outstanding on the date of such amendment or modification if such amendment or
modification would reduce the number of shares subject to such Option, increase
the purchase price applicable to shares subject to such Option or materially
adversely affect the provisions applicable to such Option that relate to the
vesting or exercisability of such Option or of the shares subject to such
Option, and (iii) no amendment or modification of the Plan shall apply to any
Option that is outstanding on the date of such amendment or modification unless
such amendment or modification of the Plan shall also apply to all other Options
outstanding on the date of such amendment or modification. In the event of any
amendment or modification of the Plan that is described in clause (i) or (ii) of
the foregoing proviso, such amendment or modification of the Plan shall apply to
any Option outstanding on the date of such amendment or modification only if the
recipient of such Option consents in writing thereto.

     The Committee may amend or modify, prospectively or retroactively, the
terms of any outstanding Option without amending or modifying the terms of the
Plan itself, PROVIDED THAT as amended or modified such Option is consistent with
the terms of the Plan as in effect at the time of the amendment or modification
of such Option, but no such amendment or modification of such Option shall,
without the written consent of the recipient of such Option, reduce the number
of shares subject to such Option, increase the purchase price applicable to
shares subject to such Option, adversely affect the provisions applicable to
such Option that relate to the vesting or exercisability of such Option or of
the shares subject to such Option, or otherwise materially adversely affect the
terms of such Option (except for amendments or modifications to the terms of
such Option or of the stock subject to such Option that are expressly permitted
by the terms of the Plan or that result from any amendment or modification of
the Plan in accordance with the provisions of the first paragraph of this
Section 13). The Committee is expressly authorized to amend any or all
outstanding Options to effect a repricing thereof by lowering the purchase price
applicable to the shares of Common Stock subject to such Option or Options
without the approval of the stockholders of the Company or the Holder or Holders
of such Option or Options, and, notwithstanding any of the foregoing provisions
of this paragraph to the contrary, in connection with such repricing to amend or
modify any of the other terms of the Option or Options so repriced, including,
without limitation, for purposes of reducing the number of shares subject to
such Option or Options or for purposes of adversely affecting the provisions
applicable to such Option or Options that relate to the vesting or
exercisability thereof, in each case without the approval of stockholders of the
Company or the Holder or Holders of such Option or Options.

     In addition, notwithstanding anything express or implied in any of the
foregoing provisions of this Section 13 to the contrary, the Committee may amend
or modify, prospectively or retroactively, the terms of any outstanding Option
to the extent the Committee reasonably determines necessary or appropriate to
conform such Option to the requirements of Section 409A of the Code (concerning
non-qualified deferred compensation), if applicable.


                                       12
<Page>



14.  INTERPRETATION OF THE PLAN

     In the event of any conflict between the provisions of this Plan and the
provisions of any applicable Option Agreement, the provisions of this Plan shall
control, except if and to the extent that the conflicting provision in such
Option Agreement was authorized and approved by the Committee at the time of the
grant of the Option evidenced by such Option Agreement or is ratified by the
Committee at any time subsequent to the grant of such Option, in which case the
conflicting provision in such Option Agreement shall control. Without limiting
the generality of the foregoing provisions of this Section 14, insofar as
possible the provisions of the Plan and such Option Agreement shall be construed
so as to give full force and effect to all such provisions. In the event of any
conflict between the provisions of this Plan and the provisions of any other
agreement between the Company and the Holder, the provisions of such agreement
shall control, but insofar as possible the provisions of the Plan and any such
agreement shall be construed so as to give full force and effect to all such
provisions.

15.  NOTICES AND OTHER COMMUNICATIONS

     Any notice, demand, request or other communication hereunder to any party
shall be deemed to be sufficient if contained in a written instrument delivered
in person or duly sent by first class registered, certified or overnight mail,
postage prepaid, or telecopied with a confirmation copy by regular, certified or
overnight mail, addressed or telecopied, as the case may be, (i) if to the
recipient of an Option, at his or her residence address last filed with the
Company and (ii) if to the Company, at its principal place of business,
addressed to the attention of its Chief Executive Officer, or to such other
address or telecopier number, as the case may be, as the addressee may have
designated by notice to the addressor. All such notices, requests, demands and
other communications shall be deemed to have been received: (i) in the case of
personal delivery, on the date of such delivery; (ii) in the case of mailing,
when received by the addressee; and (iii) in the case of facsimile transmission,
when confirmed by facsimile machine report.

16.  GOVERNING LAW

     The Plan and all Option Agreements and actions taken thereunder shall be
governed, interpreted and enforced in accordance with the laws of the
Commonwealth of Massachusetts, without regard to the conflict of laws principles
thereof.

17.  EFFECTIVENESS OF PLAN

     This 2006 Director Option Plan was approved in July 2006 by the Board and
October 2006 by the stockholders of the Company, and shall take effect only upon
the consummation of the Company's initial public offering of its Common Stock.