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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 Options.

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 (i) at any time prior to
the initial public offering of the Company, a percentage greater than fifty
percent (50%) and (ii) at any time from and after the initial public offering of
the Company, 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

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the Applicable Voting Control Percentage of the total voting power of the
outstanding capital stock of the Company, (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, and (C) within thirty days after the
Company is notified or first becomes aware of such acquisition, whichever is
earlier, a majority of the members of the board of directors of the Company as
constituted immediately prior to such acquisition do not consent in writing to
exclude such 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.

     2.15 "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.

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

     2.14. "Grant Date" means the date as of which an Option is granted, as
determined under Section 7.l(a).

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

     2.16. "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.

     2.17. "Incentive Option" means an Option which by its terms is to be
treated as an "incentive stock option" within the meaning of Section 422 of the
Code.

     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 NMS Quotation System (or on

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any other national securities exchange on which the Common Stock is then listed)
for that date or, if no closing price is reported for that date, the closing
price on the next preceding date for which a closing price was reported. For
purposes of Options granted as of the effective date of the Company's initial
public offering, Market Value shall be the price at which the Company's Common
Stock is offered to the public in its initial public offering.

     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 a person 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. "Stock Grant" means the grant of shares of Common Stock not subject
to restrictions or other forfeiture conditions.

     2.26. "Ten Percent Owner" means a person who owns, or is deemed within the
meaning of Section 422(b)(6) of the Code to own, stock possessing more than 10%
of the total combined voting power of all classes of stock of the Company (or
any parent or subsidiary corporations of the Company, as defined in Section
424(e) and (f), respectively, of the Code). Whether a person is a Ten Percent
Owner shall be determined with respect to each Option based on the facts
existing immediately prior to the Grant Date of such Option.

     2.27. "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 on the
effective date of approval of the Plan by the Board and ending immediately prior
to the tenth anniversary of the approval 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.

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4.   STOCK SUBJECT TO 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 [____________]
([_______]) shares of Common Stock; SUBJECT, HOWEVER, to the provisions of
Section 8 of the Plan. 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 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, in its
discretion, to make or to select the manner of making all determinations with
respect to each Option to be granted by the Company under the Plan in addition
to any other determination allowed the Committee under the Plan including,
without limitation: (a) the director to receive the Option; (b) the time of
granting an Option; (c) the number of shares subject to an Option; (d) the
exercise price of an Option and the method of payment of such exercise price or
such purchase price; and (e) all other terms and provisions of an Option and the
related Option Agreement. Subject to the provisions of the Plan, the Committee
shall also 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.   ELIGIBILITY

     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 following Section), 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. Subject to 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

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the Plan (whether elected at an annual or special stockholders' meeting or
appointed by action of the Board), and who prior to such election or appointment
was not immediately prior to such election or appointment a member of the Board,
shall be granted, on the date of such meeting or other appointment or election,
an Option to purchase [__________] shares of Common Stock (subject to adjustment
as set forth in Section 8). 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. Subject to the Plan's effectiveness as set forth in
Section 17, on the anniversary date of each year of service, commencing with the
2007 Annual Meeting of Stockholders of the Company for each Eligible Director
who serves on the Board upon the consummation of the initial public offering,
each Eligible Director who continues to be a director of the Company as of the
close of business of the date of such annual meeting of stockholders or other
anniversary date shall be granted an Option on such business day, to purchase
shares of Common Stock in an amount set by resolution of the Board prior to such
business day, initially to be [________] shares of Common Stock (subject to
adjustment as set forth in Section 8). Subject to Section 9, 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 Section 7 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 any Option granted pursuant to
this Section shall be ten (10) years from the date of grant.

     7.5. Exercisability. Each Option granted to an Eligible Director shall be
exercisable as follows: (a) with respect to twenty-five percent (25%) of the
shares of Common Stock underlying such Option, on the date of grant; (b) with
respect to an additional twenty-five percent (25%) of the shares of Common Stock
underlying such Option, on the first anniversary of the date of grant; (c) with
respect to an additional twenty-five percent (25%) of the shares of Common Stock
underlying such Option, on the second anniversary of the date of grant; and (d)
with respect to an additional twenty-five percent (25%) of the shares of Common
Stock underlying such Option, on the third anniversary of the date of grant.
Notwithstanding the foregoing, with respect to any Eligible Director who serves
initially in Class I or Class II immediately after the initial public offering
of the Company's Common Stock, the Committee may determine, prior to the
granting of an Option to such Eligible Director, to grant such Option on such
other vesting terms as the Committee may deem necessary or desirable. 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.

     7.6. Effect of Termination of Board Member Relationship. Unless the
Committee shall provide otherwise with respect to any Option, if the Optionee
ceases to be a director of the Company and its Affiliates, any outstanding
Option held by the Optionee or any Holder of such Option shall cease to be
exercisable in any respect not later than ninety (90) days following that

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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 subsection (f),
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. Except as
otherwise provided in this subsection (f), all of a Holder's rights in any
Option may be exercised only during the life of the Holder and only by the
Holder or the Holder's legal representative. However, the Committee may, at or
after the grant of an Option, provide that such Option may be transferred by the
recipient 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. 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 initial
grantee's household (other than a tenant or employee), a trust in which the
foregoing persons have more than fifty (50) percent of the beneficial interests,
a foundation in which the foregoing persons (or the initial grantee) control the
management of assets, and any other entity in which these persons (or the
initial grantee) own more than fifty (50) percent of the voting interests. The
Committee may at any time 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 to such
conditions, if any, as the Committee may deem necessary 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. Receipt by the Company of such
notice and payment in any authorized or combination of authorized means shall
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. Notification of Disposition. Each person exercising any Incentive
Option granted under the Plan shall be deemed to have covenanted with the
Company to report to the Company

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any disposition of such shares prior to the expiration of the holding periods
specified by Section 422(a)(l) of the Code and, if and to the extent that the
realization of income in such a disposition imposes upon the Company federal,
state, local or other withholding tax requirements, or any such withholding is
required to secure for the Company an otherwise available tax deduction, to
remit to the Company an amount in cash sufficient to satisfy those requirements.

          (j) 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.

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 as of _________, 2006.
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).

     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 replaced pursuant to
clause (C) 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 (C) 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

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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 (D).
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 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,

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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 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. Look-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

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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 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 containing provisions that are more
restrictive than the provisions set forth in the preceding sentence, 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 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.

<Page>

                                       11

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 employment, consulting
or Board member relationship 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 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, 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.

<Page>

                                       12

     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).

     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.

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.

<Page>

                                       13

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 [State of
Delaware], without regard to the conflict of laws principles thereof.

17.  EFFECTIVENESS OF PLAN

     This 2006 Director Option Plan was approved on July ___,2006 by the Board
and ____________, 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.<Page>

                                                                    Exhibit 10.5

                               ACTIVBIOTICS, INC.

                           2006 EQUITY INCENTIVE PLAN

1.   PURPOSE

     This Plan is intended to encourage ownership of Common Stock by employees,
consultants and directors of the Company and its Affiliates and to provide
additional incentive for them to promote the success of the Company's business.
The Plan is intended to be an incentive stock option plan within the meaning of
Section 422 of the Code but not all Awards granted hereunder are required to be
Incentive Options.

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, and, when used with
respect to Restricted Stock, means that the Risk of Forfeiture otherwise
applicable to such Common Stock shall expire with respect to some or all of the
shares of Restricted Stock then still otherwise subject to the Risk
of Forfeiture.

     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 (i) at any time prior to
the initial public offering of the Company, a percentage greater than fifty
percent (50%) and (ii) at any time from and after the initial public offering of
the Company, twenty percent (20%).

     2.5. "Award" means any grant or sale pursuant to the Plan of Options,
Restricted Stock or Stock Grants.

     2.6. "Award Agreement" means an agreement between the Company and the
recipient of an Award, setting forth the terms and conditions of the Award.

     2.7. "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.

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

<Page>

                                       2

     2.9. "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 App1icable Voting Control Percentage of the total voting power of
the outstanding capital stock of the Company, (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, and (C) within thirty days after the
Company is notified or first becomes aware of such acquisition, whichever is
earlier, a majority of the members of the board of directors of the Company as
constituted immediately prior to such acquisition do not consent in writing to
exclude such acquisition from the scope of this definition.

     2.10. "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.

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

     2.12. "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.

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

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

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

     2.16. "Grant Date" means the date as of which an Option is granted, as
determined under Section 7.l(a).

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

     2.18. "Incentive Option" means an Option which by its terms is to be
treated as an "incentive stock option" within the meaning of Section 422 of the
Code.

     2.19. "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 NMS Quotation System (or on any other national securities
exchange on which the Common Stock is then listed) for that date or, if no
closing price is reported for that date, the closing price on the next preceding
date for which

<Page>

                                       3

a closing price was reported. For purposes of Awards granted as of the effective
date of the Company's initial public offering, Market Value shall be the price
at which the Company's Common Stock is offered to the public in its initial
public offering.

     2.20. "Nonstatutory Option" means any Option that is not an Incentive
Option.

     2.21. "Option" means an option to purchase shares of Common Stock.

     2.22. "Optionee" means a Participant to whom an Option shall have been
initially granted under the Plan.

     2.23. "Participant" means any holder of an outstanding Award under the
Plan.

     2.24. "Plan" means this 2006 Equity Incentive Plan of the Company, as
amended and in effect from time to time.

     2.25. "Restricted Stock" means a grant or sale of shares of Common Stock to
a Participant subject to a Risk of Forfeiture.

     2.26. "Restriction Period" means the period of time, established by the
Committee in connection with an Award of Restricted Stock, during which the
shares of Restricted Stock are subject to a Risk of Forfeiture described in the
applicable Award Agreement.

     2.27. "Risk of Forfeiture" means a limitation on the right of a Participant
to retain an Award of Restricted Stock, including a right in the Company to
reacquire such Restricted Stock at less than their then Market Value, arising
because of the occurrence or non-occurrence of specified events or conditions.

     2.28. "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.

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

     2.30. "Stock Grant" means the grant of shares of Common Stock not subject
to restrictions or other forfeiture conditions.

     2.31. "Ten Percent Owner" means a person who owns, or is deemed within the
meaning of Section 422(b)(6) of the Code to own, stock possessing more than 10%
of the total combined voting power of all classes of stock of the Company (or
any parent or subsidiary corporations of the Company, as defined in Section
424(e) and (f), respectively, of the Code). Whether a person is a Ten Percent
Owner shall be determined with respect to each Option based on the facts
existing immediately prior to the Grant Date of such Option.

     2.32. "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.

<Page>

                                        4

3.   TERM OF THE PLAN

     Unless the Plan shall have been earlier terminated by the Board, Awards may
be granted under this Plan at any time in the period commencing on the effective
date of approval of the Plan by the Board and ending immediately prior to the
tenth anniversary of the earlier of the adoption of the Plan by the Board or
approval of the Plan by the Company's stockholders. Awards granted pursuant to
the Plan within such period shall not expire solely by reason of the termination
of the Plan. Awards of Incentive Options granted prior to stockholder approval
of the Plan are hereby expressly conditioned upon such approval, but in the
event of the failure of the stockholders to approve the Plan shall thereafter
and for all purposes be deemed to constitute Nonstatutory Options.

4.   STOCK SUBJECT TO THE PLAN

     At no time shall the number of shares of Common Stock issued pursuant to or
subject to outstanding Awards granted under the Plan (including, without
limitation, pursuant to Incentive Options), nor the number of shares of Common
Stock issued pursuant to Incentive Options, exceed [___________] ((______))
shares of Common Stock; SUBJECT, HOWEVER, to the provisions of Section 8 of the
Plan. 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, or if any Award of Restricted Stock is forfeited, the shares
not purchased by the Participant or forfeited by the Participant shall again be
available for Awards 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 Award
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; AND PROVIDED FURTHER
that the Committee may delegate to an executive officer or officers the
authority to grant Awards hereunder to employees who are not officers, and to
consultants, in accordance with such guidelines as the Committee shall set forth
at any time or from time to time. Subject to the provisions of the Plan, the
Committee shall have complete authority, in its discretion, to make or to select
the manner of making all determinations with respect to each Award to be granted
by the Company under the Plan in addition to any other determination allowed the
Committee under the Plan including, without limitation: (a) the employee,
consultant or director to receive the Award; (b) the form of Award; (c) whether
an Option (if granted to an employee) will be an Incentive Option or a
Nonstatutory Option; (d) the time of granting an Award; (e) the number of shares
subject to an Award; (f) the exercise price of an Option or purchase price for
shares of Restricted Stock or for a Stock Grant and the method of payment of
such exercise price or such purchase price; (g) the term of an Option; (h) the
vesting period of shares of Restricted Stock and any acceleration thereof; (i)
the exercise date or dates of an Option and any acceleration thereof; and (j)
the effect of termination of any employment, consulting or Board member
relationship with the Company or any of its Affiliates on the

<Page>

                                        5

subsequent exercisability of an Option or on the Risk of Forfeiture of
Restricted Stock. In making such determinations, the Committee may take into
account the mature of the services rendered by the respective employees,
consultants and directors, their present and potential contributions to the
success of the Company and its Affiliates, and such other factors as the
Committee in its discretion shall deem relevant. Subject to the provisions of
the Plan, the Committee shall also 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 Award 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 Award made pursuant hereto.

6.   AUTHORIZATION AND ELIGIBILITY

     The Committee may grant from time to time and at any time prior to the
termination of the Plan one or more Awards, either alone or in combination with
any other Awards, to any employee of or consultant to one or more of the Company
and its Affiliates or to any non-employee member of the Board or of any board of
directors (or similar governing authority) of any Affiliate. However, only
employees of the Company, and of any parent or subsidiary corporations of the
Company, as defined in Sections 424(e) and (f), respectively, of the Code, shall
be eligible for the grant of an Incentive Option. Further, in no event shall the
number of shares of Common Stock covered by Options or other Awards granted to
any one person in any one calendar year (or portion of a year) ending after such
date exceed [twenty five percent (25%)] of the aggregate number of shares of
Common Stock subject to the Plan.

     Each grant of an Award shall be subject to all applicable terms and
conditions of the Plan (including but not limited to any specific terms and
conditions applicable to that type of Award set out in the following Section),
and such other terms and conditions, not inconsistent with the terms of the
Plan, as the Committee may prescribe. No prospective Participant shall have any
rights with respect to an Award, unless and until such Participant has executed
an agreement evidencing the Award, delivered a fully executed copy thereof to
the Company, and otherwise complied with the applicable terms and conditions of
such Award.

7.   SPECIFIC TERMS OF AWARDS

     7.1. Options.

          (a) Date of Grant. The granting of an Option shall take place at the
time specified in the Award Agreement. Only if expressly so provided in the
applicable Award Agreement shall the Grant Date be the date on which the Award
Agreement shall have been duly executed and delivered by the Company and the
Optionee.

          (b) Exercise Price. The price at which shares of Common Stock may be
acquired under each Incentive Option shall be not less than 100% of the Market
Value of Common Stock on the Grant Date, or not less than 110% of the Market
Value of Common Stock on the Grant Date if the Optionee is a Ten Percent Owner.
The price at which shares may be acquired under each Nonstatutory Option shall
not be so limited solely by reason of this Section.

          (c) Option Period. No Incentive Option may be exercised on or after
the tenth anniversary of the Grant Date, or on or after the fifth anniversary of
the Grant Date if the

<Page>

                                        6

Optionee is a Ten Percent Owner. The Option period under each Nonstatutory
Option shall not be so limited solely by reason of this Section.

          (d) Exercisabilily. An Option may be immediately exercisable or become
exercisable in such installments, cumulative or non-cumulative, as the Committee
may determine. 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;
PROVIDED, HOWEVER, that in the case of an Incentive Option, any such
Acceleration of such Incentive Option would not cause such Incentive Option to
fail to comply with the provisions of Section 422 of the Code or the Optionee
consents to such Acceleration.

          (e) Effect of Termination of Employment, Consulting or Board Member
Relationship. Unless the Committee shall provide otherwise with respect to any
Option, if the Optionee's employment, consulting or Board member relationship
with the Company and its Affiliates ends for any reason, including because an
entity with which the Optionee has an employment, consulting or Board member
relationship ceases to be an Affiliate of the Company, any outstanding Option
held by a Participant 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. Military or sick leave or other bona fide
leave shall not be deemed a termination of employment, PROVIDED that it does not
exceed the longer of ninety (90) days or the period during which the absent
Optionee's reemployment rights, if any, are guaranteed by statute or by
contract.

          (f) Transferability. Except as otherwise provided in this subsection
(f), 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. Except as
otherwise provided in this subsection (f), all of a Participant's rights in any
Option may be exercised during the life of the Participant only by the
Participant or the Participant's legal representative. However, the Committee
may, at or after the grant of a Nonstatutory Option, provide that such Option
may be transferred by the recipient 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. 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 Optionee's household (other than a tenant
or employee), a trust in which the foregoing persons have more than fifty (50)
percent of the beneficial interests, a foundation in which the foregoing persons
(or the Optionee) control the management of assets, and any other entity in
which these persons (or the Optionee) own more than fifty (50) percent of the
voting interests.

          (g) Method of Exercise. An Option may be exercised by a Participant
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 or to avoid adverse accounting effects to
the Company, by delivery to the Company of (i) shares of Common Stock having a
Market Value equal to the exercise price of the shares to be purchased,

<Page>

                                        7

or (ii) the Participant's executed promissory note in the principal amount equal
to the exercise price of the shares to be purchased and otherwise in such form
as the Committee shall have approved. If the 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 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
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 Participant 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 (g) 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 Award 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 Optionee and the Participant with all of the provisions of the
Plan and the relevant Award Agreement.

          (h) Limit on Incentive Option Characterization. An Incentive Option
shall be considered to be an Incentive Option only to the extent that the number
of shares of Common Stock for which the Option first becomes exercisable in a
calendar year do not have an aggregate Market Value (as of the date of the grant
of the Option) in excess of the "current limit". The current limit for any
Optionee for any calendar year shall be $100,000 MINUS the aggregate Market
Value at the date of grant of the number of shares of Common Stock available for
purchase for the first time in the same year under each other Incentive Option
previously granted to the Optionee under the Plan, and under each other
incentive stock option previously granted to the Optionee under any other
incentive stock option plan of the Company and its Affiliates, after December
31, 1986. Any shares of Common Stock which would cause the foregoing limit to be
violated shall be deemed to have been granted under a separate Nonstatutory
Option, otherwise identical in its terms to those of the Incentive Option.

          (i) Notification of Disposition. Each person exercising any Incentive
Option granted under the Plan shall be deemed to have covenanted with the
Company to report to the Company any disposition of such shares prior to the
expiration of the holding periods specified by Section 422(a)(1) of the Code
and, if and to the extent that the realization of income in such a disposition
imposes upon the Company federal, state, local or other withholding tax
requirements, or any such withholding is required to secure for the Company an
otherwise available tax deduction, to remit to the Company an amount in cash
sufficient to satisfy those requirements.

          (j) 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.

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                                        8

     7.2. Restricted Stock.

          (a) Purchase Price. Shares of Restricted Stock shall be issued under
the Plan for such consideration, in cash, other property or services, or any
combination thereof, as is determined by the Committee.

          (b) Issuance of Certificates. Subject to subsection (c) below, each
Participant receiving an Award of Restricted Stock shall be issued a stock
certificate in respect of such shares of Restricted Stock. Such certificate
shall be registered in the name of such Participant, and, if applicable, shall
bear an appropriate legend referring to the terms, conditions, and restrictions
applicable to such Award substantially in the following form:

          The transferability of this certificate and the shares represented by
          this certificate are subject to the terms and conditions of the
          ActivBiotics, Inc. 2006 Equity Incentive Plan and an Award Agreement
          entered into by the registered owner and ActivBiotics, Inc. Copies of
          such Plan and Agreement are on file in the offices of ActivBiotics,
          Inc.

          (c) Escrow of Shares. The Committee may require that the stock
certificates evidencing shares of Restricted Stock be held in custody by a
designated escrow agent (which may but need not be the Company) until the
restrictions thereon shall have lapsed, and that the Participant deliver a stock
power, endorsed in blank, relating to the Common Stock covered by such Award.

          (d) Restrictions and Restriction Period. During the Restriction Period
applicable to shares of Restricted Stock, such shares shall be subject to
limitations on transferability and a Risk of Forfeiture arising on the basis of
such conditions related to the performance of services, Company or Affiliate
performance or otherwise as the Committee may determine and provide for in the
applicable Award Agreement. Any such Risk of Forfeiture may be waived or
terminated, or the Restriction Period shortened, at any time by the Committee on
such basis as it deems appropriate.

          (e) Rights Pending Lapse of Risk of Forfeiture or Forfeiture of Award.
Except as otherwise provided in the Plan or the applicable Award Agreement, at
all times prior to lapse of any Risk of Forfeiture applicable to, or forfeiture
of, an Award of Restricted Stock, the Participant shall have all of the rights
of a stockholder of the Company, including the right to vote the shares of
Restricted Stock.

          (f) Effect of Termination of Employment, Consulting or Board Member
Relationship. Unless otherwise determined by the Committee at or after grant and
subject to the applicable provisions of the Award Agreement, if a Participant's
employment, consulting or Board member relationship with the Company and its
Affiliates ends for any reason during the Restriction Period, including because
an entity with which the Participant has an employment, consulting or Board
member relationship ceases to be an Affiliate of the Company, all shares of
Restricted Stock still subject to Risk of Forfeiture shall be forfeited or
otherwise subject to return to or repurchase by the Company on the terms
specified in the Award Agreement; PROVIDED, HOWEVER, that military or sick leave
or other bona fide leave shall not be deemed a termination of employment, if it
does not exceed the longer of ninety (90) days or the period during which the
absent Participant's reemployment rights, if any, are guaranteed by statute or
by contract.

<Page>

                                        9

          (g) Lapse of Restrictions. If and when the Restriction Period expires
without a prior forfeiture of the Restricted Stock, the certificates for such
shares shall be delivered to the Participant promptly if not theretofore so
delivered.

          (h) Transferability. Except as otherwise provided in this subsection
(h), shares of Restricted Stock shall not be transferable, and no share of
Restricted Stock 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. The Committee may, at or after the grant of a
share of Restricted Stock, provide that such share of Restricted Stock may be
transferred by the recipient to a family member; PROVIDED, HOWEVER, that any
such transfer is without payment of any consideration whatsoever and that no
transfer of a share of Restricted Stock shall be valid unless first approved by
the Committee, acting in its sole discretion. 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 initial recipient's household (other than
a tenant or employee), a trust in which the foregoing persons have more than
fifty (50) percent of the beneficial interests, a foundation in which the
foregoing persons (or the initial recipient) control the management of assets,
and any other entity in which these persons (or the initial recipient) own more
than fifty (50) percent of the voting interests.

     7.3. Stock Grants.

          (a) In General. Stock Grants shall be issued for such consideration,
in cash, other property or services, or any combination thereof, as is
determined by the Committee. Without limiting the generality of the foregoing,
Stock Grants may be awarded in such circumstances as the Committee deems
appropriate, including without limitation in recognition of significant
contributions to the success of the Company or its Affiliates or in lieu of
compensation otherwise already due. Stock Grants shall be made without
forfeiture conditions of any kind.

          (b) Issuance of Certificates. Each Participant receiving a Stock Grant
shall be issued a stock certificate in respect of such Stock Grant. Such
certificate shall be registered in the name of such Participant, and, if
applicable, shall bear an appropriate legend referring to the terms, conditions,
and restrictions applicable to such Award substantially in the following form:

          The transferability of this certificate and the shares represented by
          this certificate are subject to the terms and conditions of the
          ActivBiotics, Inc. 2006 Equity Incentive Plan. A copy of such Plan is
          on file in the offices of ActivBiotics, Inc.

     7.4. Awards to Participants Outside the United States. The Committee may
modify the terms of any Award under the Plan granted to a Participant who is, at
the time of grant or during the term of the Award, 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 Award shall conform to laws,
regulations, and customs of the country in which the Participant is then
resident or primarily employed, or so that the value and other benefits of the
Award to the Participant, as affected by foreign tax laws and other restrictions
applicable as a result of the Participant's residence or employment abroad,
shall be comparable to the value of such an Award to a Participant who is
resident or primarily employed in the United States. An Award may be modified
under this Section 7.4 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

<Page>

                                       10

Committee may establish supplements to, or amendments, restatements, or
alternative versions of the Plan for the purpose of granting and administrating
any such modified Award. 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 as of ______________ __,
2006 (i.e., prior to a reverse split anticipated to occur in connection with 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
Awards, (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), and (iv) the
repurchase price of each share of Restricted Stock then subject to a Risk of
Forfeiture in the form of a Company repurchase right.

     8.2.Change of Control. Subject to the applicable provisions of the Award
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 replaced pursuant to
clause (C) 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 employment,
consulting or Board member relationship of the applicable Optionee or Optionees
with the Company and its Affiliates terminates, or at such other time or times
as the Committee shall determine; (B) the termination of any or all of the
Company's repurchase rights with respect to Restricted Stock Awards, such
termination to become effective at the time of the Change of Control, or at such
time following the Change of Control that the employment, consulting or Board
member relationship with the Company and its Affiliates of the Participant or
Participants that hold such Restricted Stock Awards (or the person to whom such
Restricted Stock Awards were initially granted) terminates, or at such other
time or times as the Committee shall determine; (C) 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 (D) the termination of all Options (other than Options that are
assumed or substituted pursuant to clause (C) 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 Participants 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

<Page>

                                       11

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 (D). 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 7.1(d) or 7.2(d) hereof to Accelerate Options in whole or in part
at any time or to waive or terminate at any time any Risk of Forfeiture
applicable to shares of Restricted Stock. 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 has an employment, consulting or Board member relationship with
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 Awards 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, Risks of Forfeiture and applicable
repurchase prices for Restricted Stock, which the Committee may deem necessary
or appropriate so as to ensure that the rights of the Participants in their
respective Awards 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 Award shall cause such number to include a 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 AWARDS

     9.1. Violation of Law. Notwithstanding any other provision of the Plan or
the relevant Award Agreement, if, at any time, in the reasonable opinion of the
Company, the issuance of shares of Common Stock covered by an Award 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:

<Page>

                                       12

          (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 Awards 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 Award, if the Committee so directs at the time of grant (or, if such Award
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 Award Agreement to the contrary, to issue such shares until such time,
if ever, as the recipient of the Award (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 Awards 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 Award unless the shares to be issued pursuant
to Awards granted under the Plan have been effectively registered under the
Securities Act or the Participant 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 Participant is acquiring shares for his or her own 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 Awards 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 Award, 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.

<Page>

                                       13

     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
Participant 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 Participant 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 Participant. 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 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 containing provisions that are more
restrictive than the provisions set forth in the preceding sentence, then (a)
each Participant (regardless of whether or not such Participant 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 Participant 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 Awards 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 Award and, if
applicable, under any agreement between the Company and any Optionee and/or
Participant, 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 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 Awards 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 Award. However, in such cases Participants 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. Participants may only elect to
have Shares withheld having a Market Value

<Page>

                                       14

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 Participant, 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 Award Agreement shall confer upon
any recipient of an Award any right with respect to the continuation of his or
her employment, consulting or Board member relationship 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 employment, consulting or Board
member agreement or provision of law or corporate articles or by-laws to the
contrary, at any time to terminate such employment, consulting or Board member
agreement or to increase or decrease, or otherwise adjust, the other terms and
conditions of the recipient's employment, consulting or Board member
relationship 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, the terms of the Plan shall survive any such
termination with respect to any Award that is outstanding on the date of such
termination, unless the holder of such Award agrees in writing to terminate such
Award or to terminate all or any of the provisions of the Plan that apply to
such Award. Unless the Board otherwise expressly provides, any amendment or
modification of the Plan shall affect the terms of any Award outstanding on the
date of such amendment or modification as well as the terms of any Award made
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 Award
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
Award, increase the purchase price applicable to shares subject to such Award or
materially adversely affect the provisions applicable to such Award that relate
to the vesting or exercisability of such Award or of the shares subject to such
Award, (ii) no amendment or modification of the Plan shall apply to any
Incentive Option that is outstanding on the date of such amendment or
modification if such

<Page>

                                       15

amendment or modification would result in such Incentive Option no longer being
treated as an "incentive stock option" within the meaning of Section 422 of the
Code and (iii) no amendment or modification of the Plan shall apply to any Award
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 Awards
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), (ii) or
(iii) of the foregoing proviso, such amendment or modification of the Plan shall
apply to any Award outstanding on the date of such amendment or modification
only if the recipient of such Award consents in writing thereto.

     The Committee may amend or modify, prospectively or retroactively, the
terms of any outstanding Award without amending or modifying the terms of the
Plan itself, PROVIDED THAT as amended or modified such Award is consistent with
the terms of the Plan as in effect at the time of the amendment or modification
of such Award, but no such amendment or modification of such Award shall,
without the written consent of the recipient of such Award, reduce the number of
shares subject to such Award, increase the purchase price applicable to shares
subject to such Award, adversely affect the provisions applicable to such Award
that relate to the vesting or exercisability of such Award or of the shares
subject to such Award, or otherwise materially adversely affect the terms of
such Award (except for amendments or modifications to the terms of such Award or
of the stock subject to such Award 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), or,
if such Award is an Incentive Option, result in such Incentive Option no longer
being treated as an "incentive stock option" within the meaning of Section 422
of the Code.

     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 Award to
the extent the Committee reasonably determines necessary or appropriate to
conform such Award to the requirements of Section 409A of the Code (concerning
non-qualified deferred compensation), if applicable.

14.  INTERPRETATION OF THE PLAN

     In the event of any conflict between the provisions of this Plan and the
provisions of any applicable Award Agreement, the provisions of this Plan shall
control, except if and to the extent that the conflicting provision in such
Award Agreement was authorized and approved by the Committee at the time of the
grant of the Award evidenced by such Award Agreement or is ratified by the
Committee at any time subsequent to the grant of such Award, in which case the
conflicting provision in such Award 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 Award 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 Optionee and/or Participant, the
provisions of such agreement shall control except as required to fulfill the
intention that this Plan constitute an incentive stock option plan within the
meaning of Section 422 of the Code, 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.

<Page>

                                       16

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 Award, 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 Award Agreements and actions taken thereunder shall be
governed, interpreted and enforced in accordance with the laws of the [State of
Delaware], without regard to the conflict of laws principles thereof.

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