Document:

<PAGE>
                                                                   EXHIBIT 10.07

             TENTH AMENDED AND RESTATED INVESTORS' RIGHTS AGREEMENT

                                 ACUSPHERE, INC.

                                 April 11, 2003
<PAGE>
                                TABLE OF CONTENTS

<TABLE>
<S>      <C>                                                                                                     <C>
1.    TERMINATION OF NINTH AMENDED INVESTORS' RIGHTS AGREEMENT; WAIVER AND CONSENT................................2
   1.1   Termination of Ninth Amended Investors' Rights Agreement.................................................2
   1.2   Waiver and Consent.......................................................................................2

2.    REGISTRATION RIGHTS.........................................................................................2
   2.1   Definitions..............................................................................................2
   2.2   Demand Registration......................................................................................5
   2.3   "Piggy-Back" Registration................................................................................6
   2.4   Form S-3 Registration....................................................................................7
   2.5   Obligations of Acusphere.................................................................................8
   2.6   Furnish Information.....................................................................................10
   2.7   Expenses of Demand and S-3 Registrations................................................................10
   2.8   Expenses of "Piggy-Back" Registration...................................................................11
   2.9   Delay of Registration...................................................................................11
   2.10  Indemnification.........................................................................................11
   2.11  Reports Under Securities Exchange Act of 1934...........................................................13
   2.12  Assignment of Registration Rights.......................................................................13
   2.13  Limitations on Subsequent Registration Rights...........................................................14
   2.14  "Market Stand-Off" Agreement............................................................................14
   2.15  Termination of Registration Rights......................................................................15

3.    COVENANTS OF ACUSPHERE.....................................................................................15
   3.1   Delivery of Financial Statements........................................................................15
   3.2   Inspection and Observation..............................................................................16
   3.3   Termination of Information, Inspection and Observation Covenants, Assignment............................16
   3.4   Right of First Refusal..................................................................................17
   3.5   Preparation of Audited Financial Statements.............................................................20
   3.6   Stock Purchase Agreements...............................................................................20
   3.7   Termination of Certain Covenants........................................................................20
   3.8   Covenants Relating to SBA Matters.......................................................................20
   3.9   Regulatory Compliance Cooperation.......................................................................21
   3.10  Consideration of Section 1202(c)........................................................................22
   3.11  Registration Rights.....................................................................................22

4.    MISCELLANEOUS..............................................................................................22
   4.1   Successors and Assigns..................................................................................22
   4.2   Governing Law...........................................................................................22
   4.3   Counterparts............................................................................................22
   4.4   Titles and Subtitles....................................................................................22
</TABLE>
<PAGE>
                                     - ii -

<TABLE>
<S>      <C>                                                                                                     <C>
   4.5   Notices.................................................................................................22
   4.6   Expenses................................................................................................23
   4.7   Amendments and Waivers..................................................................................23
   4.8   Severability............................................................................................23
   4.9   Aggregation of Stock....................................................................................23
   4.10  Entire Agreement........................................................................................23
</TABLE>
<PAGE>
             TENTH AMENDED AND RESTATED INVESTORS' RIGHTS AGREEMENT

      THIS TENTH AMENDED AND RESTATED INVESTORS' RIGHTS AGREEMENT (this
"Agreement") is made as of the 11th day of April, 2003, by and among Acusphere,
Inc., a Delaware corporation ("Acusphere"), and those investors listed on
Schedule A attached hereto (the "Investors"); and, solely for purposes of
Sections 1, 3.4 and 4 of this Agreement, Sherri C. Oberg ("Oberg").

                                    RECITALS

      WHEREAS, certain of the Investors hold shares of Acusphere's Series A-1
Convertible Preferred Stock, $.01 par value per share (the "Series A-1 Stock"),
Series A-2 Convertible Preferred Stock, $.01 par value per share (the "Series
A-2 Stock"), Series B-1 Convertible Preferred Stock, $.01 par value per share
(the "Series B-1 Stock"), Series B-2 Convertible Preferred Stock, $.01 par value
per share (the "Series B-2 Stock"), Series C-1 Convertible Preferred Stock, $.01
par value per share (the "Series C-1 Stock"), Series C-2 Convertible Preferred
Stock, $.01 par value per share (the "Series C-2 Stock"), Series D-1 Convertible
Preferred Stock, $.01 par value per share (the "Series D-1 Stock"), Series D-2
Convertible Preferred Stock, $.01 par value per share (the "Series D-2 Stock"),
Series E-1 Convertible Preferred Stock, $.01 par value per share (the "Series
E-1 Stock"), Series E-2 Convertible Preferred Stock, $.01 par value per share
(the "Series E-2 Stock"), Series F-1 Convertible Preferred Stock, $.01 par value
per share (the "Series F-1 Stock"), Series F-2 Convertible Preferred Stock, $.01
par value per share (the "Series F-2 Stock"), Series I-1 Convertible Preferred
Stock, $.01 par value share (the "Series I-1 Stock"), Series I-2 Convertible
Preferred Stock, $.01 par value per share (the "Series I-2 Stock"), Series J
Convertible Preferred Stock, $.01 par value per share (the "Series J Stock"),
Series J-1 Convertible Preferred Stock, $.01 par value per share (the "Series
J-1 Stock"), Series J-2 Convertible Preferred Stock, $.01 par value per share
(the "Series J-2 Stock"), and/or Series J-3 Convertible Preferred Stock, $.01
par value per share (the "Series J-3 Stock," together with the Series A-1 Stock,
Series A-2 Stock, Series B-1 Stock, Series B-2 Stock, Series C-1 Stock, Series
C-2 Stock, Series D-1 Stock, Series D-2 Stock, Series E-1 Stock, Series E-2
Stock, Series F-1 Stock, Series F-2 Stock, Series I-1 Stock, Series I-2 Stock,
Series J Stock, Series J-1 Stock and Series J-2 Stock, the "Preferred Stock");

      WHEREAS, a certain Investor, Alexandria Real Estate Equities, L.P.
("Alexandria"), holds a warrant to purchase (i) prior to 12:00 midnight, Boston
time, on July 1, 2003 shares of Series F-1 Non-Voting Convertible Preferred
Stock, $.01 par value per share (the "Series F-1 Non-Voting Stock"), and (ii)
from and following such time, shares of Series F-2 Non-Voting Convertible
Preferred Stock, $.01 par value per share (the "Series F-2 Non-Voting Stock")
(the "Alexandria Warrant Shares");

      WHEREAS, certain Investors, GATX Ventures, Inc. ("GATX") and Venture
Lending & Leasing III, LLC ("VLL"), hold warrants to purchase (i) prior to 12:00
midnight, Boston time, on July 1, 2003 shares of Series F-1 Non-Voting Stock,
and (ii) from and following such time, shares of shares of Series F-2 Non-Voting
Stock (the "Venture Lender Warrant Shares");
<PAGE>
                                      -2-

      WHEREAS, each such Investor possesses certain registration and other
rights in connection therewith pursuant to a Ninth Amended and Restated
Investors' Rights Agreement, dated as of June 17, 2002, by and among Acusphere
and such Investors, (the "Ninth Amended Investors' Rights Agreement");

      WHEREAS, certain Investors are parties to a Convertible Note and Warrant
Purchase and Securities Exchange Agreement, dated as of the date hereof (as
amended and in effect from time to time, the "Note and Warrant Purchase
Agreement"), which provides, inter alia, (i) for the purchase by such Investors
of 10% convertible promissory notes (the "Notes") and warrants to purchase
shares of Acusphere's equity securities (the "Warrants") and (ii) for the
exchange of certain shares of Existing Preferred (as defined therein) for shares
of New Preferred (as defined therein); and

      WHEREAS, among the conditions to the consummation of the transactions
contemplated by the Note and Warrant Purchase Agreement is the execution and
delivery of this Agreement; and

      WHEREAS, each of the parties hereto desires to set forth in a single
document such registration and certain other rights of the Investors.

      NOW, THEREFORE, in consideration of the mutual promises, covenants and
conditions hereinafter set forth and for other good and valuable consideration,
Acusphere, each Investor and Oberg, severally and not jointly, hereby agree as
follows:

1. Termination of Ninth Amended Investors' Rights Agreement; Waiver and Consent.

      1.1 Termination of Ninth Amended Investors' Rights Agreement. The parties
hereto hereby acknowledge and agree that the Ninth Amended Investors' Rights
Agreement is hereby amended, restated and superseded in all respects by this
Agreement.

      1.2 Waiver and Consent. The Investors and all other parties to the Ninth
Amended Investors' Rights Agreement hereby (i) consent to the issuance of the
Notes, Warrants and New Preferred in accordance with the terms of the Note and
Warrant Purchase Agreement (including all closings described therein) and (ii)
waive all preemptive rights and rights of first refusal, and all related notice
provisions, under all existing agreements with respect to the issuance by
Acusphere of such Notes, Warrants, and New Preferred, including any shares of
capital stock issued or issuable upon conversion, exercise, or exchange (as
applicable) of such securities, and the shares of Common Stock, if any, issued
or issuable upon conversion thereof.

2. Registration Rights. Acusphere covenants and agrees as follows:

      2.1 Definitions. For purposes of this Section 2:

            (a) The term "Act" means the Securities Act of 1933, as amended.

            (b) The term "Alexandria Registrable Securities" means (i) those
shares of Common Stock issued or
<PAGE>
                                      -3-

issuable upon conversion of the Alexandria Warrant Shares issued or issuable
upon exercise of that certain Warrant Agreement by and between Acusphere and
Alexandria, dated March 30, 2001 (the "Alexandria Warrant") and (ii) any common
stock of Acusphere issued as (or issuable upon the conversion or exercise of any
warrant, right or other security which is issued as) a dividend or other
distribution with respect to, or in exchange for or in replacement of the shares
referenced in (i) above, excluding in all cases, however, any Registrable
Securities sold by a person in a transaction in which the rights under this
Section 2 are not assigned.

            (c) The term "Bridge Note Registrable Securities" means (i) those
shares of Common Stock issued or issuable upon conversion of those shares of
Acusphere capital stock, if any, issued upon conversion or exchange of any Notes
issued pursuant to the Note and Warrant Purchase Agreement, and (ii) any shares
of common stock of Acusphere issued as (or issuable upon the conversion or
exercise of any warrant, right or other security which is issued as) a dividend
or other distribution with respect to, or in exchange for or in replacement of
the shares referenced in (i) above, excluding in all cases, however, any Bridge
Note Registrable Securities sold by a person in a transaction in which the
rights under this Section 2 are not assigned.

            (d) The term "Bridge Warrant Registrable Securities" means (i) those
shares of Common Stock issued or issuable upon conversion of those shares of
Acusphere capital stock issued or then issuable upon exercise of any Warrants
issued pursuant to the Note and Warrant Purchase Agreement, and (ii) any shares
of common stock of Acusphere issued as (or issuable upon the conversion or
exercise of any warrant, right or other security which is issued as) a dividend
or other distribution with respect to, or in exchange for or in replacement of
the shares referenced in (i) above, excluding in all cases, however, any Bridge
Warrant Registrable Securities sold by a person in a transaction in which the
rights under this Section 2 are not assigned.

            (e) The term "Common Stock" means shares of Common Stock, $.0l par
value per share, of Acusphere.

            (f) The term "Form S-1" means such form under the Act as in effect
on the date hereof, or any registration form under the Act subsequently adopted
by the SEC which permits the registration of securities under the Act for which
no other form is authorized or prescribed.

            (g) The term "Form S-3" means such form under the Act as in effect
on the date hereof or any registration form under the Act subsequently adopted
by the SEC which permits inclusion or incorporation of substantial information
by reference to other documents filed by Acusphere with the SEC.

            (h) The term "Holder" means any person owning or having the right to
acquire Registrable Securities or any assignee thereof in accordance with
Section 2.12 hereof.

            (i) The term "1934 Act" shall mean the Securities Exchange Act of
1934, as amended.
<PAGE>
                                      -4-

            (j) The terms "register," "registered," and "registration" refer to
a registration effected by preparing and filing a registration statement or
similar document in compliance with the Act, and the declaration or ordering of
effectiveness of such registration statement or document.

            (k) The term "Registrable Securities" means (A) (i) the Common Stock
issuable or issued upon conversion of the Series A-1 Stock, the Series A-2
Stock, the Series B-1 Stock, the Series B-2 Stock, the Series C-1 Stock, the
Series C-2 Stock, the Series D-1 Stock, the Series D-2 Stock, the Series E-1
Stock, the Series E-2 Stock, the Series F-1 Stock, the Series F-2 Stock, the
Series I-1 Stock, the Series I-2 Stock, the Series J Stock, the Series J-1
Stock, the Series J-2 Stock and the Series J-3 Stock, (ii) any Common Stock of
Acusphere issued as (or issuable upon the conversion or exercise of any warrant,
right or other security which is issued as) a dividend or other distribution
with respect to, or in exchange for or in replacement of the shares referenced
in (i) above, (iii) the Bridge Note Registrable Securities, (iv) the Bridge
Warrant Registrable Securities, (v) the Alexandria Registrable Securities, and
(vi) the Venture Lender Registrable Securities, excluding in all cases, however,
any Registrable Securities sold by a person in a transaction in which the rights
under this Section 2 are not assigned, and (B) solely for the purposes of
Sections 2.1, 2.3 through 2.15, 3.11, 4.1, 4.7 and 4.9 of this Agreement, the
Alexandria Registrable Securities and the Venture Lender Registrable Securities.

            (l) The number of shares of "Registrable Securities then
outstanding" shall be determined by the number of shares of Common Stock
outstanding which are, and the number of shares of Common Stock issuable
pursuant to then exercisable or convertible securities which are, Registrable
Securities.

            (m) The term "SEC" means the Securities and Exchange Commission.(n)
The term "SBIC Investor" means any Investor that is a Small Business Investment
Company, as defined in 13 C.F.R. Section 107.

            (o) The term "Venture Lender Registrable Securities" means (i) those
shares of Common Stock issued or issuable upon conversion of the Venture Lender
Warrant Shares issued or issuable upon exercise of that certain Warrant
Agreement by and between Acusphere and GATX, dated as of September 27, 2001 (the
"GATX Warrant"), and that certain Warrant Agreement by and between Acusphere and
VLL, dated as of September 27, 2001 (the "VLL Warrant"), and (ii) any common
stock of Acusphere issued as (or issuable upon the conversion or exercise of any
warrant, right or other security which is issued as) a dividend or other
distribution with respect to, or in exchange for or in replacement of the shares
referenced in (i) above, excluding in all cases, however, any Registrable
Securities sold by a person in a transaction in which the rights under this
Section 2 are not assigned.

      2.2 Demand Registration.

            (a) If Acusphere shall receive at any time after the earlier of (i)
June 17, 2005 or (ii) six months after the closing of an initial public offering
of securities of Acusphere (other than a registration statement relating either
to the sale of securities to employees of Acusphere pursuant to a stock option,
stock purchase or similar plan or a SEC Rule 145 transaction), a
<PAGE>
                                      -5-

written request from (i) the Holders of at least forty percent (40%) of the
Registrable Securities then outstanding, (ii) the Holders of at least a majority
of the Series F-1 Stock, Series F-2 Stock, Series I-1 Stock, Series I-2 Stock,
Series J Stock, Series J-1 Stock, Series J-2 Stock and Series J-3 Stock then
outstanding (including, for such purposes, any shares of Common Stock issued
upon conversion thereof), that Acusphere effect a registration statement under
the Act with respect to all or a part of the Registrable Securities, then
Acusphere shall:

                  (i) within ten (10) days of the receipt thereof, give written
      notice of such request to all Holders; and

                  (ii) effect as soon as practicable, and in any event within
      ninety (90) days of the receipt of such request, the registration under
      the Act of all Registrable Securities which the Holders request to be
      registered, subject to the limitations of subsection 2.2(b), within thirty
      (30) days of the mailing of such notice by Acusphere in accordance with
      Section 4.5.

            (b) If the Holders initiating the registration request hereunder
(the "Initiating Holders") intend to distribute the Registrable Securities
covered by their request by means of an underwriting, they shall so advise
Acusphere as a part of their request made pursuant to subsection 2.2(a) and
Acusphere shall include such information in the written notice referred to in
subsection 2.2(a). The underwriter will be selected by a majority in interest of
the Initiating Holders, subject to the reasonable approval of Acusphere. In such
event, the right of any Holder to include Registrable Securities in such
registration shall be conditioned upon such Holder's participation in such
underwriting and the inclusion of such Holder's Registrable Securities in the
underwriting to the extent provided herein. All Holders proposing to distribute
their securities through such underwriting shall (together with Acusphere as
provided in subsection 2.5(e)) enter into an underwriting agreement in customary
form with the underwriter or underwriters selected for such underwriting.
Notwithstanding any other provision of this Section 2.2, if the underwriter
advises the Initiating Holders in writing that marketing factors require a
limitation of the number of shares to be underwritten, then the Initiating
Holders shall so advise all Holders of Registrable Securities which would
otherwise be underwritten pursuant hereto, and the number of shares of
Registrable Securities that may be included in the underwriting shall be
allocated among all Holders thereof, including the Initiating Holders, in
proportion (as nearly as practicable) to the amount of Registrable Securities of
Acusphere owned by each Holder; provided, however, that the number of shares of
Registrable Securities to be included in such underwriting shall not be reduced
unless all other securities are first entirely excluded from the underwriting.

            (c) Notwithstanding the foregoing, if Acusphere shall furnish to the
Holders requesting registration pursuant to this Section 2.2, a certificate
signed by the Chief Executive Officer of Acusphere stating that in the good
faith judgment of the Board of Directors of Acusphere, it would be seriously
detrimental to Acusphere and its stockholders for a registration statement to be
filed and it is, therefore, essential to defer the filing of such registration
statement, Acusphere shall have the right to defer taking action with respect to
such filing for a period of not more than one hundred twenty (120) days after
receipt of the request of the
<PAGE>
                                      -6-

Initiating Holders; provided, however, that Acusphere may not utilize this right
more than once in any twelve-month period.

            (d) Acusphere shall not be obligated to effect, or to take any
action to effect, any registration pursuant to this Section 2.2 after Acusphere
has effected four (4) registrations on Form S-1 or its then equivalent pursuant
to this Section 2.2 and such registration statements have been declared or
ordered effective and the sales of Registrable Securities under such
registration statements have closed; provided, however, that each such
obligation shall be deemed to be satisfied only when a registration statement
covering at least sixty percent (60%) or more of the Registrable Securities held
by the Holders initiating such registration and requested to be included in such
registration statement has been declared or ordered effective and the sale of
such Registrable Securities under such registration statements have closed; and
further provided, however, that in any event (i) the Holders of at least forty
percent (40%) of the Registrable Securities shall be entitled to at least one
demand registration pursuant to Section 2.2(a) hereto, and (ii) the Holders of
at least a majority of the Series F-1 Stock, Series F-2 Stock, Series I-1 Stock,
Series I-2 Stock, Series J Stock, Series J-1 Stock, Series J-2 Stock and Series
J-3 Stock (including, for such purposes, any shares of Common Stock issued upon
conversion thereof) shall be entitled to at least one demand registration
pursuant to Section 2.2(a) hereto.

            (e) No incidental right under this Section 2.2 shall be construed to
limit any registration required under Section 2.3 or Section 2.4 herein.

      2.3 "Piggy-Back" Registration.

            (a) If (but without any obligation to do so) Acusphere proposes to
register (including for this purpose a registration effected by Acusphere for
stockholders other than the Holders) any of its stock or other securities under
the Act in connection with the public offering of such securities solely for
cash (other than a registration relating solely to the sale of securities to
participants in a stock plan, a registration on any form which does not include
substantially the same information as would be required to be included in a
registration statement covering the sale of the Registrable Securities, a
registration in which the only Common Stock being registered is Common Stock
issuable upon conversion of debt securities which are also being registered, or
a registration relating to the sale of securities in connection with a
transaction covered by Rule 145 promulgated under the Act), Acusphere shall, at
such time, promptly give each Holder written notice of such registration. Upon
the written request of each Holder given within twenty (20) days after mailing
of such notice by Acusphere in accordance with Section 4.5, Acusphere shall,
subject to the provisions of subsection 2.3(b), cause to be registered under the
Act all of the Registrable Securities that each such Holder has requested to be
registered.

            (b) Underwriting Requirements. In connection with any offering
involving an underwriting of shares of Acusphere's capital stock, Acusphere
shall not be required under this Section 2.3 to include any of the Holders'
securities in such underwriting unless such Holders accept the terms of the
underwriting as agreed upon between Acusphere and the underwriters selected by
it (or by other persons entitled to select the underwriters pursuant to the
terms of this Agreement), and then only in such quantity as the underwriters
determine in their sole discretion will not jeopardize the success of the
offering by Acusphere. If the total amount of securities,
<PAGE>
                                      -7-

including Registrable Securities, requested by stockholders to be included in
such offering exceeds the amount of securities to be sold (other than by
Acusphere) that the underwriters determine in their sole discretion is
compatible with the success of the offering, then Acusphere shall be required to
include in the offering only that number of such securities, including
Registrable Securities, which the underwriters determine in their sole
discretion will not jeopardize the success of the offering; provided, however,
there shall first be excluded from such registration statement all shares of
Common Stock sought to be included therein by (i) any director, consultant,
officer or employee of Acusphere or any subsidiary of Acusphere (except those
joining such registration pursuant to the Stock Repurchase and Registration
Agreement, dated April 30, 1996, among Acusphere, Robert S. Langer, Harry R.
Allcock and Sherri C. Oberg, the "Founders' Registration Agreement"), and (ii)
stockholders exercising any contractual or incidental registration rights
subordinate and junior to the rights of the Holders of Registrable Securities.
Thereafter, the shares of Common Stock sought to be included in such
registration statement pursuant to this Agreement and, if applicable, the
Founders' Registration Agreement, shall be excluded from such registration
statement in proportion (as nearly as practicable) to the amount of such shares
owned by the holders of such shares. If after such shares are excluded, the
underwriters shall determine in their sole discretion that the number of
securities which remain to be included in the offering exceeds the amount of
securities to be sold that the underwriters determine is compatible with the
success of the offering, then the Common Stock to be included, if any, shall be
apportioned pro rata among the holders of Common Stock providing notice of their
desire to participate in the offering pursuant to this Agreement and the
Founders' Registration Agreement (the "Selling Stockholders") according to the
total amount of securities entitled to be included therein owned by each Selling
Stockholder, or in such other proportions as shall mutually be agreed to by such
Selling Stockholders. Notwithstanding the foregoing, in no event shall the
amount of securities of the Selling Stockholders included in the offering be
reduced below thirty percent (30%) of the total amount of securities included in
such offering, unless such offering is the initial public offering of
Acusphere's securities in which case the Selling Stockholders may be excluded if
the underwriters make the determination described above and no other
stockholder's securities are included. For purposes of the preceding sentence
concerning apportionment, for any Selling Stockholder which is a partnership or
corporation, the partners, retired partners and stockholders of such Selling
Stockholder, or the estates and family members of any such partners and retired
partners and any trusts for the benefit of any of the foregoing persons shall be
deemed to be a single "Selling Stockholder", and any pro-rata reduction with
respect to such "selling holder" shall be based upon the aggregate amount of
shares carrying registration rights owned by all entities and individuals
included in such "Selling Stockholder", as defined in this sentence.

            (c) No incidental right under this Section 2.3 shall be construed to
limit any registration required under Section 2.2 or Section 2.4 herein.

      2.4 Form S-3 Registration. In case Acusphere shall receive from any Holder
or Holders of Registrable Securities a written request or requests that
Acusphere effect a registration on Form S-3 and any related qualification or
compliance with respect to all or a part of the Registrable Securities owned by
such Holder or Holders, Acusphere will:
<PAGE>
                                      -8-

            (a) promptly give written notice of the proposed registration, and
any related qualification or compliance, to all other Holders; and

            (b) as soon as practicable, effect such registration and all such
qualifications and compliances as may be so requested and as would permit or
facilitate the sale and distribution of all or such portion of such Holder's or
Holders' Registrable Securities as are specified in such request, together with
all or such portion of the Registrable Securities of any other Holder or Holders
joining in such request as are specified in a written request given within
fifteen (15) days after receipt of such written notice from Acusphere; provided,
however, that Acusphere shall not be obligated to effect any such registration,
qualification or compliance, pursuant to this Section 2.4: (i) if Form S-3 is
not available for such offering by the Holders; (ii) if the Holders, together
with the holders of any other securities of Acusphere entitled to inclusion in
such registration, propose to sell Registrable Securities and such other
securities (if any) at an aggregate price to the public of less than $3,000,000;
or (iii) if Acusphere shall furnish to the Holders a certificate signed by the
Chief Executive Officer of Acusphere stating that in the good faith judgment of
the Board of Directors of Acusphere, it would be seriously detrimental to
Acusphere and its stockholders for such Form S-3 registration to be effected at
such time, in which event Acusphere shall have the right to defer the filing of
the Form S-3 registration statement for a period of not more than sixty (60)
days after receipt of the request of the Holder or Holders under this Section
2.4; provided, however, that Acusphere shall not utilize this right more than
once in any twelve (12) month period.

            (c) Subject to the foregoing, Acusphere shall file a registration
statement covering the Registrable Securities and other securities so requested
to be registered as soon as practicable after receipt of the request or requests
of the Holders. At the election of a majority in interest of the Holders of
Registrable Securities to be included in such registration statement, such
registration may be firmly underwritten by a managing underwriter selected by
such Holders, and, if so elected, be subject to the requirements and provisions
of Section 2.2(b). Registrations effected pursuant to this Section 2.4 shall not
be counted as demands for registration or registrations effected pursuant to
Sections 2.2 or 2.3, respectively.

      2.5 Obligations of Acusphere. Whenever required under this Section 2 to
effect the registration of any Registrable Securities, Acusphere shall, as
expeditiously as reasonably possible:

            (a) Prepare and file with the SEC a registration statement with
respect to such Registrable Securities and use its best efforts to cause such
registration statement to become effective, and, upon the request of the Holders
of a majority of the Registrable Securities registered thereunder, keep such
registration statement effective for a period of up to one hundred twenty (120)
days or until the distribution contemplated in the Registration Statement has
been completed; provided, however, that (i) such 120-day period shall be
extended for a period of time equal to the period the Holder refrains from
selling any securities included in such registration at the request of an
underwriter of Common Stock (or other securities) of Acusphere; and (ii) in the
case of any registration of Registrable Securities on Form S-3 which are
intended to be offered on a continuous or delayed basis, such 120-day period
shall be extended, if necessary, to keep the registration statement effective
until all such Registrable Securities are sold, provided that
<PAGE>
                                      -9-

Rule 415, or any successor rule under the Act, permits an offering on a
continuous or delayed basis, and provided further that applicable rules under
the Act governing the obligation to file a post-effective amendment permit, in
lieu of filing a post-effective amendment which (A) includes any prospectus
required by Section 10(a)(3) of the Act or (B) reflects facts or events
representing a material or fundamental change in the information set forth in
the registration statement, the incorporation by reference of information
required to be included in (A) and (B) above to be contained in periodic reports
filed pursuant to Section 13 or 15(d) of the 1934 Act in the registration
statement.

            (b) Prepare and file with the SEC such amendments and supplements to
such registration statement and the prospectus used in connection with such
registration statement as may be necessary to comply with the provisions of the
Act with respect to the disposition of all securities covered by such
registration statement.

            (c) Furnish to the Holders such numbers of copies of a prospectus,
including a preliminary prospectus, in conformity with the requirements of the
Act, and such other documents as they may reasonably request in order to
facilitate the disposition of Registrable Securities owned by them.

            (d) Use its best efforts to register and qualify the securities
covered by such registration statement under such other securities or Blue Sky
laws of such jurisdictions as shall be reasonably requested by the Holders;
provided that Acusphere shall not be required in connection therewith or as a
condition thereto to qualify to do business or to file a general consent to
service of process in any such states or jurisdictions, unless Acusphere is
already subject to service in such jurisdiction and except as may be required by
the Act.

            (e) In the event of any underwritten public offering, enter into and
perform its obligations under an underwriting agreement, in usual and customary
form, with the managing underwriter of such offering. Each Holder participating
in such underwriting shall also enter into and perform its obligations under
such an agreement.

            (f) Notify each Holder of Registrable Securities covered by such
registration statement at any time when a prospectus relating thereto is
required to be delivered under the Act as a result of the happening of any event
as a result of which the prospectus included in such registration statement, as
then in effect, includes an untrue statement of a material fact or omits 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 then
existing.

            (g) Cause all such Registrable Securities registered pursuant
hereunder to be listed on each securities exchange on which similar securities
issued by Acusphere are then listed.

            (h) Provide a transfer agent and registrar for all Registrable
Securities registered pursuant hereunder and a CUSIP number for all such
Registrable Securities, in each case not later than the effective date of such
registration.
<PAGE>
                                      -10-

            (i) Furnish, at the request of any Holder requesting registration of
Registrable Securities pursuant to this Section 2, on the date that such
Registrable Securities are delivered to the underwriters for sale in connection
with a registration pursuant to this Section 2, if such securities are being
sold through underwriters, or, if such securities are not being sold through
underwriters, on the date that the registration statement with respect to such
securities becomes effective, (i) an opinion, dated such date, of the counsel
representing Acusphere for the purposes of such registration, in form and
substance as is customarily given to underwriters in an underwritten public
offering, addressed to the underwriters, if any, and to the Holders requesting
registration of Registrable Securities and (ii) a letter dated such date, from
the independent certified public accountants of Acusphere, in form and substance
as is customarily given by independent certified public accountants to
underwriters in an underwritten public offering, addressed to the underwriters,
if any, and to the Holders requesting registration of Registrable Securities.

            (j) Make available for inspection by each seller of Registrable
Securities, any underwriter participating in any distribution pursuant to such
registration statement, and any attorney, accountant or other agent retained by
such seller or underwriter, all financial and other records, pertinent corporate
documents and properties of Acusphere, and cause Acusphere's officers, directors
and employees to participate in "road show" meetings with potential investors
and to supply all information reasonably requested by any such seller,
underwriter, attorney, accountant or agent in connection with such registration
statement.

      2.6 Furnish Information. It shall be a condition precedent to the
obligations of Acusphere to take any action pursuant to this Section 2 with
respect to the Registrable Securities of any selling Holder that such Holder
shall furnish to Acusphere such information regarding itself, the Registrable
Securities held by it, and the intended method of disposition of such securities
as shall be required to effect the registration of such Holder's Registrable
Securities.

      2.7 Expenses of Demand and S-3 Registrations. All expenses other than
underwriting discounts and commissions incurred in connection with
registrations, filings or qualifications pursuant to Sections 2.2 and 2.4,
including (without limitation) all registration, filing and qualification fees,
printers' and accounting fees, fees and disbursements of counsel for Acusphere
and transfer taxes, if any, and the reasonable fees and disbursements of one
counsel for the selling Holders shall be borne by Acusphere; provided, however,
that Acusphere shall not be required to pay for any expenses of any registration
proceeding begun pursuant to Section 2.2 or 2.4 if the registration request is
subsequently withdrawn at the request of the Holders of a majority of the
Registrable Securities to be registered (in which case all Holders participating
in the registration shall bear such expenses), unless, in the case of a
registration pursuant to Section 2.2, the Holders of a majority of the
Registrable Securities agree to forfeit their right to one demand registration
pursuant to Section 2.2; provided further, however, that if at the time of such
withdrawal, the Holders have learned of a material adverse change in the
condition, business, or prospects of Acusphere from that known to the Holders at
the time of their request and have withdrawn the request with reasonable
promptness following disclosure by Acusphere of such material adverse change,
then the Holders shall not be required to pay any of such expenses and shall
retain their rights under Sections 2.2 and 2.4.
<PAGE>
                                      -11-

      2.8 Expenses of "Piggy-Back" Registration. Acusphere shall bear and pay
all expenses incurred in connection with any registration, filing or
qualification of Registrable Securities with respect to the registrations
pursuant to Section 2.3 for each Holder, including (without limitation) all
registration, filing, and qualification fees, printers' and accounting fees
relating or apportionable thereto and transfer taxes, if any, and the fees and
disbursements of one counsel for the selling Holders selected by them, but
excluding underwriting discounts and commissions relating to the Registrable
Securities.

      2.9 Delay of Registration. No Holder shall have any right to obtain or
seek an injunction restraining or otherwise delaying any such registration as
the result of any controversy that might arise with respect to the
interpretation or implementation of this Section 2.

      2.10 Indemnification. In the event any Registrable Securities are included
in a registration statement under this Section 2:

            (a) To the extent permitted by law, Acusphere will indemnify and
hold harmless each Holder, any underwriter (as defined in the Act) for such
Holder and each person, if any, who controls such Holder or underwriter within
the meaning of the Act or the 1934 Act, against any losses, claims, damages, or
liabilities (joint or several) to which they may become subject under the Act,
the 1934 Act or other federal or state law, insofar as such losses, claims,
damages, or liabilities (or actions in respect thereof) arise out of or are
based upon any of the following statements, omissions or violations
(collectively a "Violation"): (i) any untrue statement or alleged untrue
statement of a material fact contained in such registration statement, including
any preliminary prospectus or final prospectus contained therein or any
amendments or supplements thereto, (ii) the omission or alleged omission to
state therein a material fact required to be stated therein, or necessary to
make the statements therein not misleading, or (iii) any violation or alleged
violation by Acusphere of the Act, the 1934 Act, any state securities law or any
rule or regulation promulgated under the Act, the 1934 Act or any state
securities law; and Acusphere will pay to each such Holder, underwriter or
controlling person, as incurred, any legal or other expenses reasonably incurred
by them in connection with investigating or defending any such loss, claim,
damage, liability, or action; provided, however, that the indemnity agreement
contained in this subsection 2.10(a) shall not apply to amounts paid in
settlement of any such loss, claim, damage, liability, or action if such
settlement is effected without the consent of Acusphere (which consent shall not
be unreasonably withheld), nor shall Acusphere be liable in any such case for
any such loss, claim, damage, liability, or action to the extent that it arises
out of or is based upon a Violation which occurs in reliance upon and in
conformity with written information furnished expressly for use in connection
with such registration by any such Holder, underwriter or controlling person.

            (b) To the extent permitted by law, each selling Holder, severally
but not jointly, will indemnify and hold harmless Acusphere, each of its
directors, each of its officers who has signed the registration statement, each
person, if any, who controls Acusphere within the meaning of the Act, any
underwriter, any other Holder selling securities in such registration statement
and any controlling person of any such underwriter or other Holder, against any
losses, claims, damages, or
<PAGE>
                                      -12-

liabilities, to which any of the foregoing persons may become subject, under the
Act, the 1934 Act or other federal or state law, insofar as such losses, claims,
damages, or liabilities (or actions in respect thereto) arise out of or are
based upon any Violation, in each case to the extent (and only to the extent)
that such Violation occurs in reliance upon and in conformity with written
information furnished by such Holder expressly for use in connection with such
registration; and each such Holder will pay, as incurred, any legal or other
expenses reasonably incurred by any person intended to be indemnified pursuant
to this subsection 2.10(b), in connection with investigating or defending any
such loss, claim, damage, liability, or action; provided, however, that the
indemnity agreement contained in this subsection 2.10(b) shall not apply to
amounts paid in settlement of any such loss, claim, damage, liability or action
if such settlement is effected without the consent of the Holder, which consent
shall not be unreasonably withheld; provided, that, in no event shall any
indemnity under this subsection 2.10(b) exceed the net proceeds from the
offering received by such Holder.

            (c) Promptly after receipt by an indemnified party under this
Section 2.10 of notice of the commencement of any action (including any
governmental action), such indemnified party will, if a claim in respect thereof
is to be made against any indemnifying party under this Section 2.10, deliver to
the indemnifying party a written notice of the commencement thereof and the
indemnifying party shall have the right to participate in, and, to the extent
the indemnifying party so desires, jointly with any other indemnifying party
similarly noticed, to assume the defense thereof with counsel mutually
satisfactory to the parties; provided, however, that an indemnified party
(together with all other indemnified parties which may be represented without
conflict by one counsel) shall have the right to retain one separate counsel,
with the fees and expenses to be paid by the indemnifying party, if the
indemnified party shall have reasonably concluded that there may be reasonable
defenses available to it which are different from or additional to those
available to the indemnifying party or if the interests of the indemnified party
reasonably may be deemed to conflict with the interests of the indemnifying
party. The failure to deliver written notice to the indemnifying party within a
reasonable time of the commencement of any such action, if prejudicial to its
ability to defend such action, shall relieve such indemnifying party of any
liability to the indemnified party under this Section 2.10, but the omission so
to deliver written notice to the indemnifying party will not relieve it of any
liability that it may have to any indemnified party otherwise than under this
Section 2.10.

            (d) If the indemnification provided for in this Section 2.10 is held
by a court of competent jurisdiction to be unavailable to an indemnified party
with respect to any loss, liability, claim, damage, or expense referred to
therein, then the indemnifying party, in lieu of indemnifying such indemnified
party hereunder, shall contribute to the amount paid or payable by such
indemnified party as a result of such loss, liability, claim, damage, or expense
in such proportion as is appropriate to reflect the relative fault of the
indemnifying party on the one hand and of the indemnified party on the other in
connection with the statements or omissions that resulted in such loss,
liability, claim, damage, or expense as well as any other relevant equitable
considerations. The relative fault of the indemnifying party and of the
indemnified party shall be determined by reference to, among other things,
whether the untrue or alleged untrue statement of a material fact or the
omission to state a material fact relates to information supplied by the
indemnifying party or by the indemnified party and the parties' relative intent,
knowledge, access to information, and opportunity to correct or prevent such
statement or omission; provided, that, in the case of contribution by a selling
Holder, in no event shall any contribution under this subsection 2.10(d) exceed
the net proceeds from the offering received by such contributing party.

<PAGE>

                                      -13-

            (e) Notwithstanding the foregoing, to the extent that the provisions
on indemnification and contribution contained in the underwriting agreement
entered into in connection with the underwritten public offering are in conflict
with the foregoing provisions, the provisions in the underwriting agreement
shall control.

            (f) The obligations of Acusphere and Holders under this Section 2.10
shall survive the completion of any offering of Registrable Securities in a
registration statement under this Section 2, and otherwise.

      2.11 Reports Under Securities Exchange Act of 1934. With a view to making
available to the Holders the benefits of Rule 144 promulgated under the Act and
any other rule or regulation of the SEC that may at any time permit a Holder to
sell securities of Acusphere to the public without registration or pursuant to a
registration on Form S-3, Acusphere agrees to use its best efforts to:

            (a) make and keep public information available, as those terms are
understood and defined in SEC Rule 144, at all times after ninety (90) days
after the effective date of the first registration statement filed by Acusphere
for the offering of its securities to the general public;

            (b) take such action, including the voluntary registration of its
Common Stock under Section 12 of the 1934 Act, as is necessary to enable the
Holders to utilize Form S-3 for the sale of their Registrable Securities, such
action to be taken as soon as practicable after the end of the fiscal year in
which the first registration statement filed by Acusphere for the offering of
its securities to the general public is declared effective;

            (c) file with the SEC in a timely manner all reports and other
documents required of Acusphere under the Act and the 1934 Act; and

            (d) furnish to any Holder, so long as the Holder owns any
Registrable Securities, forthwith upon request (i) a written statement by
Acusphere that it has complied with the reporting requirements of SEC Rule 144
(at any time after ninety (90) days after the effective date of the first
registration statement filed by Acusphere), the Act and the 1934 Act (at any
time after it has become subject to such reporting requirements), or that it
qualifies as a registrant whose securities may be resold pursuant to Form S-3
(at any time after it so qualifies), (ii) a copy of the most recent annual or
quarterly report of Acusphere and such other reports and documents so filed by
Acusphere, and (iii) such other information as may be reasonably requested in
availing any Holder of any rule or regulation of the SEC which permits the
selling of any such securities without registration or pursuant to such form.

      2.12 Assignment of Registration Rights. The rights to cause Acusphere to
register Registrable Securities pursuant to this Section 2 may be assigned (but
only with all related obligations) by a Holder only to a transferee or assignee
of such securities who, after such assignment or transfer, holds at least 75,000
shares of Registrable Securities (subject to appropriate adjustment for stock
splits, stock dividends, combinations and other recapitalizations), provided:
(a) Acusphere is, within a reasonable time after such transfer, furnished with
written notice of the name and address of such transferee or assignee and the
<PAGE>
                                      -14-

securities with respect to which such registration rights are being assigned;
(b) such transferee or assignee agrees in writing to be bound by and subject to
the terms and conditions of this Agreement, including without limitation the
provisions of Section 2.14 below; and (c) such assignment shall be effective
only if immediately following such transfer the further disposition of such
securities by the transferee or assignee is restricted under the Act.

      2.13 Limitations on Subsequent Registration Rights. From and after the
date of this Agreement, Acusphere shall not, without the prior written consent
of the Holders of a majority of the Registrable Securities then outstanding,
enter into any agreement with any holder or prospective holder of any securities
of Acusphere which would allow such holder or prospective holder (a) to include
such securities in any registration filed under Section 2.2 or described in
Section 2.3 hereof, unless under the terms of such agreement, such holder or
prospective holder may include such securities in any such registration only to
the extent that the inclusion of such securities will not reduce the amount of
the Registrable Securities of the Holders which are to be included or (b) to
make a demand registration which could result in such registration statement
being declared effective prior to the earlier of either of the dates set forth
in subsection 2.2(a) or within one hundred twenty (120) days of the effective
date of any registration effected pursuant to Section 2.2 or 2.4.

      2.14 "Market Stand-Off" Agreement. Each Investor hereby agrees that,
during the period of duration (not to exceed one hundred eighty (180) days)
specified by Acusphere and an underwriter of Common Stock or other securities of
Acusphere, following the effective date of a registration statement of Acusphere
filed under the Act, such Investor shall not, to the extent requested by
Acusphere and such underwriter, directly or indirectly sell, offer to sell,
contract to sell (including, without limitation, any short sale), grant any
option to purchase or otherwise transfer or dispose of (other than to donees who
agree to be similarly bound) any securities of Acusphere held by it at any time
during such period except Common Stock included in such registration; provided,
however, that:

            (a) such agreement shall be applicable only with respect to a
      registration statement covering Acusphere's initial public offering of
      securities; and
            (b) all officers and directors of Acusphere and all other persons
      with registration rights (whether or not pursuant to this Agreement) enter
      into similar agreements.

            In order to enforce the foregoing covenant, Acusphere may impose
stop-transfer instructions with respect to the Registrable Securities of an
Investor (and the shares or securities of every other person subject to the
foregoing restriction) until the end of such period.

            Notwithstanding the foregoing, the obligations described in this
Section 2.14 shall not apply to a registration relating solely to employee
benefit plans on Form S-1 or Form S-8 or similar forms which may be promulgated
in the future, or a registration relating solely to a SEC Rule 145 transaction
on Form S-4 or similar forms which may be promulgated in the future.
<PAGE>
                                      -15-

      2.15 Termination of Registration Rights. No Holder shall be entitled to
exercise any right provided for in this Section 2 if there is then an active
public trading market for the Common Stock, such Holder may sell all of such
Holder's Registrable Securities under Rule 144 promulgated under the Act in a
three-month period and such Holder's Registrable Securities represent less than
3% of Acusphere's outstanding shares of capital stock. No holder shall be
entitled to exercise any right provided for in Section 2.2 after five (5) years
following the consummation of the sale of securities pursuant to a registration
statement filed by Acusphere under the Act in connection with the initial firm
commitment underwritten offering of its securities to the general public.

3. Covenants of Acusphere.

      3.1 Delivery of Financial Statements. Acusphere shall deliver to each
Significant Investor (as defined in Section 3.2(b) hereof), as long as such
Investor holds shares of Preferred Stock (or any shares of Common Stock issuable
upon conversion thereof):

            (a) as soon as practicable, but in any event within ninety (90) days
after the end of each fiscal year of Acusphere, an income statement for such
fiscal year, a balance sheet of Acusphere and statement of stockholders' equity
as of the end of such year, and a schedule as to the sources and applications of
funds for such year, such year-end financial reports to be in reasonable detail,
prepared in accordance with generally accepted accounting principles ("GAAP"),
and audited and certified by independent public accountants of nationally
recognized standing selected by Acusphere;

            (b) as soon as practicable, but in any event within forty-five (45)
days after the end of each of the first three (3) quarters of each fiscal year
of Acusphere, an unaudited profit or loss statement and schedule as to the
sources and application of funds for such fiscal quarter and an unaudited
balance sheet as of the end of such fiscal quarter;

            (c) within thirty (30) days of the end of each month, an unaudited
income statement and schedule as to the sources and application of funds and
balance sheet for and as of the end of such month, in reasonable detail;

            (d) as soon as practicable, but in any event forty-five (45) days
prior to the end of each fiscal year, a budget and business plan for the next
fiscal year, prepared on a monthly basis, including balance sheets and sources
and applications of funds statements for such months and, as soon as prepared,
any other budgets or revised budgets prepared by Acusphere;

            (e) with respect to the financial statements called for in
subsections (a), (b) and (c) of this Section 3.1, an instrument executed by the
Chief Financial Officer or Chief Executive Officer of Acusphere and certifying
that such financials were prepared in accordance with GAAP consistently applied
with prior practice for earlier periods (with the exception of footnotes that
may be required by GAAP) and fairly present the financial condition of Acusphere
and its results of operation for the period specified, subject to year-end audit
adjustment; and
<PAGE>
                                      -16-

            (f) such other information relating to the financial condition,
business, prospects or corporate affairs of Acusphere as such Significant
Investor or any assignee of such Significant Investor may from time to time
request, provided, however, that Acusphere shall not be obligated under this
subsection (f) or any other subsection of Section 3.1 to provide information
which it deems in good faith to be a trade secret or similar confidential
information.

      3.2 Inspection and Observation.

            (a) Acusphere shall permit each Significant Investor (as defined in
Section 3.2(b) hereof), at such Significant Investor's expense, to visit and
inspect Acusphere's properties, to examine its books of account and records and
to discuss Acusphere's affairs, finances and accounts with its officers, all at
such reasonable times as may be requested by such Significant Investor;
provided, however, that Acusphere shall not be obligated pursuant to this
Section 3.2 to provide access to any information which its Board of Directors
reasonably considers to be a trade secret or similar confidential information.

            (b) Acusphere will permit any Significant Investor (as hereinafter
defined), any authorized representative thereof or any Investor holding shares
of Series E-1 Stock and/or Series E-2 Stock and at least five percent (5%) of
the Common Stock on a fully-diluted basis, assuming the conversion or exercise,
as the case may be, of all outstanding securities or rights to acquire shares of
Acusphere's Common Stock (each, a "Series E Five-Percent Holder"), to attend all
meetings of the Board of Directors of Acusphere in a nonvoting observer capacity
and shall, upon the written request of such Significant Investor or Series E
Five-Percent Holder, provide such Significant Investor or Series E Five-Percent
Holder with such notice and other information with respect to such meetings as
are delivered to the directors of Acusphere; provided, however, that it is
hereby acknowledged and agreed that only a single representative of each group
consisting of a Significant Investor and its affiliates will be entitled to
attend any such meeting pursuant to this Section 3.2(b). Upon the written
request of any such Significant Investor or Series E Five-Percent Holder,
Acusphere shall notify such Significant Investor or Series E Five-Percent
Holder, within ten (10) days thereof, of the taking of any action by the Board
of Directors of Acusphere in lieu of a meeting thereof. As used in this Section
3, the term "Significant Investor" shall mean any Investor other than Alexandria
who, together with its affiliates, holds at least 200,000 shares of Preferred
Stock, including Common Stock issuable upon the conversion of Preferred Stock,
(as presently constituted and subject to subsequent adjustment for stock splits,
stock dividends, reverse stock splits, recapitalizations and the like).

      3.3 Termination of Information, Inspection and Observation Covenants,
Assignment. The covenants set forth in Section 3.1 and Section 3.2 shall
terminate as to each Investor and be of no further force or effect when the sale
of securities pursuant to a registration statement filed by Acusphere under the
Act in connection with the firm commitment underwritten offering of its
securities to the general public is consummated or when Acusphere first becomes
subject to the periodic reporting requirements of Sections 12(g) or 15(d) of the
1934 Act, whichever event shall first occur. The rights to receive and access
information relating to Acusphere pursuant to Sections 3.1 and 3.2 may be
assigned (but only with all related obligations) by an Investor to a transferee
or assignee of such securities who, after such assignment or transfer, holds at
least 75,000 shares of Registrable Securities (subject to appropriate adjustment
for stock splits, stock
<PAGE>
                                      -17-

dividends, combinations and other recapitalizations), provided: (a) Acusphere
is, within a reasonable time after such transfer, furnished with written notice
of the name and address of such transferee or assignee and the securities with
respect to which such information rights are being assigned; and (b) such
transferee or assignee agrees in writing to be bound by and subject to the terms
and conditions of this Agreement.

      3.4 Right of First Refusal. Subject to the terms and conditions specified
in this Section 3.4, Acusphere hereby grants to each of the Investors a right of
first refusal with respect to future sales by Acusphere of its Shares and
Venture Capital Shares (each, as hereinafter defined). For purposes of this
Section 3.4 and Section 4 only, the term "Investor" shall include Oberg and any
general partners and affiliates of an Investor. Each Investor shall be entitled
to apportion the right of first refusal hereby granted it among itself and its
partners and affiliates in such proportions as it deems appropriate. For
purposes hereof, an "affiliate" of any Investor is an entity or a person that
directly or indirectly controls, is controlled by, or is under common control
with such Investor. For purposes hereof, (i) all notice provisions shall be
deemed satisfied with respect to any general partner or affiliate of an Investor
if such notice is deemed satisfied with respect to such Investor, (ii) all
waiver and amendment provisions shall be deemed satisfied with respect to any
general partner or affiliate of an Investor if such waiver or amendment is
deemed satisfied with respect to such Investor, and (iii) in no event shall any
Investor, its general partners and its affiliates, together as a group, have a
right pursuant to this Section 3.4 to purchase in the aggregate more than such
Investor's pro rata portion of the Shares and Venture Capital Shares, if any,
offered hereby.

            Each time Acusphere proposes to offer any shares of, or securities
convertible into or exercisable for any shares of, any class of its capital
stock (the "Shares"), Acusphere shall first make an offering of such Shares to
the Investors in accordance with the following provisions:

            (a) Acusphere shall deliver a notice by certified mail (the
"Notice") to each Investor other than Alexandria (the "Remaining Investors")
stating (i) its bona fide intention to offer such Shares, (ii) the number of
such Shares to be offered, and (iii) the price and terms, if any, upon which it
proposes to offer such Shares. If the Shares being offered by Acusphere are
offered in connection with a Venture Capital Financing (as defined in paragraph
(c) below), the Notice shall be delivered to the Remaining Investors
simultaneously with the Alexandria Notice (as defined below) delivered to
Alexandria.

            (b) Within thirty (30) calendar days after receipt of the Notice,
each Remaining Investor may elect to purchase or obtain, at the price and on the
terms specified in the Notice (provided, that, in the event any such
consideration is non-cash consideration, at the election of such Remaining
Investor, such Remaining Investor may pay cash equal to the fair market value of
such non-cash consideration, and provided, that, the closing of any such
purchase may be extended to any such Remaining Investor for purposes of
obtaining necessary governmental approvals), some or all of such Remaining
Investor's pro rata portion of the Shares offered by Acusphere in the Notice.
Each Remaining Investor's pro rata portion of such Shares shall be equal to a
fraction of such Shares, the numerator of which is the number of shares of
Registrable Securities or Common Stock as the case may be, then held by such
Remaining Investor and the denominator of which shall be equal to the sum of the
total number of shares of
<PAGE>
                                      -18-

Registrable Securities and Common Stock then held by all Remaining Investors. If
any Remaining Investor does not elect to exercise its or his right to purchase
its or his total pro rata portion of the Shares, Acusphere shall promptly give
notice of such failure to the other Remaining Investors who did elect to
purchase (the "Participants"). Each Remaining Investor shall have a right of
over-allotment such that if any Remaining Investor fails to exercise its or his
right to purchase its or his total pro rata portion of the Shares, the
Participants may purchase such portion, by giving written notice to Acusphere
with five (5) days from the date that Acusphere provides written notice to the
other Participants of the number of Shares with respect to which such
non-purchasing Remaining Investor has failed to exercise its rights hereunder.

            (c) Notwithstanding the foregoing rights contained in clause (b) of
this Section 3.4, if such Shares are offered in connection with a private
placement pursuant to a Venture Capital Financing (as defined below) ("Venture
Capital Shares"), Acusphere shall first deliver a notice by certified mail (the
"Alexandria Notice") to Alexandria stating (i) its bona fide intention to offer
such Venture Capital Shares, (ii) the number of Venture Capital Shares to be
offered, and (iii) the price and terms, if any, upon which it proposes to offer
such Venture Capital Shares. Within thirty (30) calendar days after receipt of
the Alexandria Notice, Alexandria may elect to purchase or obtain, at the price
and on the terms specified in the Alexandria Notice (provided, that, in the
event any such consideration is non-cash consideration, at the election of
Alexandria, Alexandria may pay cash equal to the fair market value of such
non-cash consideration, and provided, that, the closing of any such purchase may
be extended to Alexandria for purposes of obtaining necessary governmental
approvals), such number of Venture Capital Shares as is equal the number of
Venture Capital Shares determined by dividing $250,000 by the per share price at
which the Venture Capital Shares are offered by Acusphere. The term "Venture
Capital Financing" as used herein shall refer to the sale by Acusphere of
Venture Capital Shares in a private placement to one or more institutional
investors resulting in aggregate gross proceeds to Acusphere of at least
$5,000,000, excluding any securities issued in connection with an acquisition
transaction. In the foregoing clauses (a) and (b) of this Section 3.4, the term
Shares shall exclude any such Shares which constitute Venture Capital Shares and
which are purchased by Alexandria pursuant to this clause (c).

            (d) If the Investors do not elect to purchase all of the Shares and
Venture Capital Shares, if applicable, referred to in the Notice and Alexandria
Notice, if applicable, Acusphere may, during the 90-day period following the
expiration of the periods provided in subsections 3.4(b) and (c) hereof
(including the additional five day period provided for over-allotments), offer
the remaining unsubscribed portion of such Shares and Venture Capital Shares, if
applicable, to any person or persons at a price not less than, and upon terms no
more favorable to the offeree than those specified in the Notice and Alexandria
Notice, if applicable. If Acusphere does not enter into an agreement for the
sale of the unsubscribed portion of such Shares and Venture Capital Shares,
within such period, or if such agreement is not consummated within thirty (30)
days of the execution thereof, the right provided hereunder shall be deemed to
be revived and such Shares and Venture Capital Shares, shall not be offered
unless first reoffered to the Investors in accordance herewith; provided,
however, that if during such 90-day period, Acusphere offers such Shares and
Venture
<PAGE>
                                      -19-

Capital Shares, if applicable, to any person or persons at a price and/or upon
terms more favorable to the offeree than those specified in the Notice and
Alexandria Notice, if applicable, then Acusphere must first reoffer the Shares
and Venture Capital Shares, if applicable, to the Investors on such favorable
terms and the procedure set forth above shall be followed, with the exception
that the 30-day periods set forth in subsections 3.4(a) and (c) shall be a
15-day period.

            (e) The rights of first refusal in this Section 3.4 shall not be
applicable (i) to the issuance or sale on or after March 30, 1994, of up to
6,591,977 shares of Common Stock (or options therefor) to Acusphere's employees,
consultants, or directors (adjusted to reflect subsequent stock dividends, stock
splits or recapitalizations affecting the number of outstanding shares of the
Common Stock) for the primary purpose of soliciting or retaining their services,
provided each such employee, consultant or director executes an agreement
providing for (A) vesting of shares (or the option to purchase shares) over at
least a four-year period, (B) market stand-off agreements similar to that set
forth in Section 2.14 of this Agreement, and (C) rights of first refusal on
transfers of such shares which shall first be a right of Acusphere, then of
Acusphere's assignees; provided, however, that any such requirements may be
waived by action of Acusphere's Board of Directors, provided that all
representatives of the Investors on the Board of Directors of Acusphere consent
to such waiver, (ii) to the issuance of securities in or after consummation of a
bona fide, firmly underwritten initial public offering of shares of Common
Stock, registered under the Act pursuant to a registration statement on Form S-1
or other available form, (iii) to the issuance of securities pursuant to the
conversion of convertible securities, (iv) to the issuance of 130,169 and 22,216
shares of Common Stock to the Massachusetts Institute of Technology ("MIT") on
or about March 30, 1995 and June 4, 1996, respectively, (v) to the issuance of
securities solely to prevent dilution as a result of any stock splits, stock
dividends, combinations, recapitalizations or issuances of securities below the
then applicable conversion price for the Preferred Stock, (vi) to the issuance
of securities (including options, warrants or convertible securities and the
securities issuable upon conversion or exercise of such options, warrants or
convertible securities) to lending or leasing institutions pursuant to debt or
lease financing arrangements approved by the Board of Directors, including all
of the directors then serving on the Board of Directors which were designated by
the holders of the Company's Preferred Stock in accordance with the Ninth
Amended and Restated Voting Agreement, dated as of the date hereof, as amended
and in effect from time to time (the "Voting Agreement"), not to exceed, in the
aggregate, five percent (5.0%) of the capital stock of Acusphere on a
fully-diluted basis (assuming the conversion or exercise of all outstanding
option, warrants or convertible securities), (vii) to the issuance of the Notes
and Warrants issued pursuant to the Note and Warrant Purchase Agreement
(including the shares of Acusphere capital stock, if any, issued or issuable
upon conversion, exercise or exchange thereof, and the Common Stock issued or
issuable upon conversion thereof), (viii) to the issuance of Series G
Paid-in-Kind Dividends pursuant to Section 1.8 Acusphere's Tenth Amended and
Restated Certificate of Incorporation, or (ix) to the issuance of the Alexandria
Warrant, the GATX Warrant, or the VLL Warrant, or the Alexandria Warrant Shares
or the Venture Lender Warrant Shares issued or issuable upon exercise thereof,
and the shares of Common Stock issued or issuable upon conversion thereof.

            (f) The right of first refusal set forth in this Section 3.4 may be
assigned (but only with all related obligations) by a Holder only to a
transferee or assignee of such securities who, after such assignment or
transfer, holds at least 75,000 shares of Registrable Securities (subject to
appropriate adjustment for stock splits, stock dividends, combinations and other
<PAGE>
                                      -20-

recapitalizations), provided: (a) Acusphere is, within a reasonable time after
such transfer, furnished with written notice of the name and address of such
transferee or assignee and the securities with respect to which such
registration rights are being assigned; (b) such transferee or assignee agrees
in writing to be bound by and subject to the terms and conditions of this
Agreement; and (c) such assignment shall be effective only if immediately
following such transfer the further disposition of such securities by the
transferee or assignee is restricted under the Act.

      3.5 Preparation of Audited Financial Statements. Acusphere shall undertake
to prepare and shall deliver to each Investor other than Alexandria, as soon as
practicable, its audited financial statements (balance sheet, profit and loss
statement, statement of stockholders' equity and statement of cash flows,
including notes thereon) as of December 31, 2002, and for each fiscal year
thereafter.

      3.6 Stock Purchase Agreements. All officers and employees of and
consultants to Acusphere who purchase shares of Acusphere's capital stock shall
be required to execute a stockholder agreement providing for (i) vesting of
shares (or option to purchase shares) over a four-year period, (ii) market
stand-off agreements similar to that set forth in Section 2.14 of this
Agreement, and (iii) rights of first refusal on transfers of such shares which
shall first be a right of Acusphere, then of Acusphere's assignees; provided
however, that any such requirements may be waived by action of Acusphere's Board
of Directors, provided that any representative of the Investors on the Board of
Directors of Acusphere consents to such waiver.

      3.7 Termination of Certain Covenants. The provisions set forth in Section
3.6 shall terminate and be of no further force or effect upon the consummation
of the sale of securities pursuant to a registration statement filed by
Acusphere under the Act in connection with the firm commitment underwritten
offering of its securities to the general public.

      3.8 Covenants Relating to SBA Matters. At such times as any SBIC Investor
holds any securities of Acusphere, Acusphere shall comply with the covenants set
forth in this Section 3.8.

            (a) Use of Proceeds. The proceeds from the prior issuances and sales
of preferred stock which the Company still retains (the "Proceeds") shall be
used by Acusphere for its growth, modernization or expansion. Acusphere shall
provide each SBIC Investor and the Small Business Administration (the "SBA")
reasonable access to Acusphere's books and records for the purpose of confirming
the use of Proceeds.

            (b) Business Activity. During the period ending on April 25, 2001,
Acusphere shall not change the nature of its business activity if such change
would render Acusphere ineligible as provided in 13 C.F.R. Section 107.720.

            (c) Compliance. So long as any SBIC Investor holds any securities of
Acusphere, Acusphere will at all times comply with the non-discrimination
requirements of 13 C.F.R. Parts 112, 113 and 117.
<PAGE>
                                      -21-

            (d) Information. Within 45 days after the end of each fiscal year
and at such other times as an SBIC Investor may reasonably request, Acusphere
shall deliver to such SBIC Investor a written assessment, in form and substance
satisfactory to such SBIC Investor, of the economic impact of such SBIC
Investor's investment specifying the full-time equivalent jobs created or
retained in connection with such investment, and the impact of the investment on
Acusphere's business in terms of profits and on taxes paid by Acusphere and its
employees. Upon request, Acusphere promptly (and in any event within 20 days of
such request) will furnish to each SBIC Investor all information reasonably
requested by such SBIC Investor in order for such SBIC Investor to comply with
the requirements of 13 C.F.R. Section 107.620 or to prepare and file SBA Form
468 and any other information requested or required by any governmental agency
asserting jurisdiction over such SBIC Investor. Acusphere shall afford to
representatives of the SBA reasonable access to the books, records and
properties of Acusphere and its subsidiaries. Any submission of any financial
information under Section 3.1, above, or this Section 3.8(d) shall include a
certificate of Acusphere's president, chief executive officer, treasurer or
chief financial officer. If a SBIC Investor requests confidential information
from Acusphere for the purpose of providing such information to the SBA, then,
if requested in writing by Acusphere at the time Acusphere provides such
information to such SBIC Investor, the SBIC Investor shall, to the extent
permitted by law, request that such confidential information be treated
confidentially by the SBA.

            (e) Number of Holders of Voting Securities. Acusphere shall notify
each SBIC Investor (i) on or prior to the taking of any action which increases
the number of record holders of Acusphere's voting securities from fewer than 50
to 50 or more, and (ii) of any other action or occurrence which increases the
number of record holders of Acusphere's voting securities from fewer than 50 to
50 or more, as soon as practicable after Acusphere becomes aware that such other
action or occurrence has occurred or is proposed to occur.

      3.9 Regulatory Compliance Cooperation. In the event that either Bank of
America Ventures or BancBoston Ventures determines that it has a Regulatory
Problem (as defined below), it shall have the right to transfer its Registrable
Securities without regard to any restrictions on transfer set forth in this
Agreement, the Note and Warrant Purchase Agreement, the Voting Agreement, or the
Third Amended and Restated Stock Restriction Agreement dated as of the date
hereof and in effect from time to time (the "Stock Restriction Agreement") and
Acusphere shall take all such actions as are reasonably requested by Bank of
America Ventures or BancBoston Ventures, as applicable, in order to (i)
effectuate and facilitate any transfer by it of any securities of Acusphere then
held by it to any person designated by Bank of America Ventures or BancBoston
Ventures, as applicable, provided that such person is reasonably acceptable to
Acusphere and agrees in writing to be bound by this Agreement, the Note and
Warrant Purchase Agreement, the Voting Agreement, and the Stock Restriction
Agreement, (ii) permit Bank of America Ventures or BancBoston Ventures (or any
of their affiliates), as applicable, to exchange all or any portion of any
voting security of Acusphere then held by it on a share-for-share basis for
shares of a nonvoting security of Acusphere, which nonvoting security shall be
identical in all respects to the voting security exchanged for it, except that
it shall be nonvoting and shall be convertible into a voting security on such
terms as are requested by it in light of regulatory considerations then
prevailing and (iii) amend this Agreement, as amended from time to time, to
effectuate and reflect the foregoing. The parties to this Agreement agree to
<PAGE>
                                      -22-

vote all of Acusphere's securities held by them in favor of such amendments and
actions. For purposes of this Agreement, a "Regulatory Problem" means any set of
facts or circumstances wherein it has been asserted by any governmental
regulatory agency that Bank of America Ventures or BancBoston Ventures is not
entitled to hold, or exercise any significant right with respect to securities
of Acusphere.

      3.10 Consideration of Section 1202(c). At such time or times, if any, that
Acusphere considers repurchasing any shares of its Preferred Stock, Acusphere
agrees to consider the effect that such repurchase would have on such stock's
qualification as "Qualified Small Business Stock," as defined in Section 1202(c)
of the Internal Revenue Code of 1986, as amended (the "Code"). Notwithstanding
the foregoing, Acusphere shall have no obligation to take, or refrain from
taking any action that would affect such stock's status as "Qualified Small
Business Stock." Acusphere will use reasonable efforts to comply with the
reporting and recordkeeping requirements of Section 1202 of the Code and the
regulations promulgated thereunder.

      3.11 Registration Rights. Acusphere shall not grant to any person or
entity registration rights which are on par with or senior to the registration
rights granted to the holders of the Registrable Securities, unless holders of a
majority of the then outstanding shares of Registrable Securities consent in
writing.

4. Miscellaneous.

      4.1 Successors and Assigns. Except as otherwise provided herein, the terms
and conditions of this Agreement shall inure to the benefit of and be binding
upon the respective successors and assigns of the parties (including transferees
of any shares of Registrable Securities). Nothing in this Agreement, express or
implied, is intended to confer upon any party other than the parties hereto or
their respective successors and assigns any rights, remedies, obligations, or
liabilities under or by reason of this Agreement, except as expressly provided
in this Agreement.

      4.2 Governing Law. This Agreement shall be governed by and construed under
the laws of the Commonwealth of Massachusetts as applied to agreements among
Massachusetts residents entered into and to be performed entirely within
Massachusetts.

      4.3 Counterparts. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument. Any person who may, after
the date hereof, purchase Notes and Warrants pursuant to the Note and Warrant
Purchase Agreement shall become a party to this Agreement as an "Investor" and a
holder of "Notes," "Warrants," "Bridge Note Registrable Securities," "Bridge
Warrant Registrable Securities," and "Registrable Securities," as applicable for
all purposes hereunder, all upon execution of a counterpart to this Agreement
signed by such person and Acusphere.

      4.4 Titles and Subtitles. The titles and subtitles used in this Agreement
are used for convenience only and are not to be considered in construing or
interpreting this Agreement.

      4.5 Notices. Unless otherwise provided, any notice required or permitted
under this Agreement shall be given in writing and shall be deemed effectively
given (i) upon personal
<PAGE>
                                      -23-

delivery to the party to be notified, (ii) upon deposit with the United States
Post Office, by registered or certified mail, postage prepaid or (iii) one day
after deposit with a nationally recognized overnight courier, specifying next
day delivery, with written verification of receipt. All communications shall be
sent to the party to be notified at the address as set forth on the signature
pages hereof or the exhibits hereto or at such other address as such party may
designate by advance written notice to the other parties hereto; provided,
however, that registered or certified mail shall not be used to effectuate
delivery of any such notice, demand or other communication to any such parties
with principal places of business located outside the United States.

      4.6 Expenses. If any action at law or in equity is necessary to enforce or
interpret the terms of this Agreement, the prevailing party shall be entitled to
reasonable attorneys' fees, costs and necessary disbursements in addition to any
other relief to which such party may be entitled.

      4.7 Amendments and Waivers. Any term of this Agreement may be amended and
the observance of any term of this Agreement may be waived (either generally or
in a particular instance and either retroactively or prospectively), only with
the written consent of Acusphere and the holders of at least 55% of the
Registrable Securities then outstanding (provided that if an amendment or waiver
affects any Investor in a manner that is different from the effect of such
waiver or amendment on all other Investors, then the consent of such Investor
shall be required for such amendment or waiver, and further provided that no
such amendment or waiver will be effective to increase any obligations of Oberg
without her written consent). Any amendment or waiver effected in accordance
with this paragraph shall be binding upon each holder of any Registrable
Securities then outstanding, each future holder of all such Registrable
Securities, and Acusphere.

      4.8 Severability. If one or more provisions of this Agreement are held to
be unenforceable under applicable law, such provision shall be excluded from
this Agreement and the balance of the Agreement shall be interpreted as if such
provision were so excluded and shall be enforceable in accordance with its
terms.

      4.9 Aggregation of Stock. All shares of Registrable Securities held or
acquired by affiliated entities or persons shall be aggregated together for the
purpose of determining the availability of any rights under this Agreement.

      4.10 Entire Agreement. This Agreement (including the Exhibits and
Schedules hereto, if any) constitutes the full and entire understanding and
agreement between the parties with regard to the subjects hereof and thereof.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]
<PAGE>
                               AMENDMENT NO. 1 TO
                           TENTH AMENDED AND RESTATED
             INVESTORS' RIGHTS AGREEMENT, DATED AS OF APRIL 11, 2003

      (a)   Section 3.7 is hereby deleted in its entirety and replaced with the
            following:

            "3.7. Termination of Certain Covenants. The provisions set forth in
            Sections 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.8, 3.9, 3.10 and 3.11 shall
            terminate and be of no further force or effect upon the earlier of
            (i) the closing of a firm commitment underwritten public offering
            pursuant to an effective registration statement under the Securities
            Act covering the offer and sale of Acusphere's Common Stock and (ii)
            the closing of a transaction or series of transactions resulting in
            a Change of Control, as defined in Acusphere's Amended and Restated
            Certificate of Incorporation, as amended and in effect from time to
            time."

      (b)   Except as hereby amended, the Investors' Rights Agreement shall
            remain in full force and effect.
<PAGE>
      IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date first above written.

                                  ACUSPHERE, INC.
                                  500 Arsenal Street
                                  Watertown, MA 02472

                                  By: /s/ Sherri C. Oberg
                                      ------------------------------------------
                                      Sherri C. Oberg
                                      President and Chief Executive Officer
<PAGE>
                                  MVI MEDICAL VENTURE
                                  INVESTMENTS LIMITED
                                  c/o New Medical Technologies
                                  Attention: Beat R. Merz, Dr. sc. Techn.
                                  Elisabethenstrasse 23
                                  CH-4051 Basel
                                  Switzerland

                                  By: /s/ John Arnold
                                      ------------------------------------------
                                      Name: John Arnold
                                      Title: Director
<PAGE>
                                  DIAMOND CAPITAL MANAGEMENT, INC. (as
                                  Investment Advisor for the Retirement
                                  Program Plan for Employees of Union
                                  Carbide Corporation and its
                                  Participating Subsidiary Companies)

                                  c/o The Dow Chemical Company
                                  1320 Waldo Avenue, DORINCO 100
                                  Midland, MI 48674

                                  By: /s/ G. N. van Drunen
                                      ------------------------------------------
                                      Name: G. N. van Drunen
                                      Title: Director of Alternative Investments
<PAGE>
                                  BANK OF AMERICA VENTURES
                                  950 Tower Lane, Suite 700
                                  Foster City, CA 94404

                                  By: /s/ Kate D. Mitchell
                                      ----------------------------------------
                                      Name: Kate D. Mitchell
                                      Title: Managing Director

                                  BA VENTURE PARTNERS II
                                  c/o BankAmerica Ventures
                                  950 Tower Lane, Suite 700
                                  Foster City, CA 94404

                                  By: /s/ Robert M. Obuch
                                      ----------------------------------------
                                      Name: Robert M. Obuch
                                      Title: General Partner
<PAGE>
                                  ALTA V LIMITED PARTNERSHIP
                                  200 Clarendon Street, 51st Floor
                                  Boston, MA 02116

                                  By: Alta V Management Partners, L.P.

                                  By: /s/ Eileen McCarthy
                                      ------------------------------------------
                                      Name: Eileen McCarthy
                                      Title: General Partner

                                  CUSTOMS HOUSE PARTNERS
                                  200 Clarendon Street, 51st Floor
                                  Boston, MA 02116

                                  By: /s/ Eileen McCarthy
                                      ------------------------------------------
                                      Name: Eileen McCarthy
                                      Title: Under Power of Attorney
<PAGE>
                                  POLARIS VENTURE PARTNERS, L.P.
                                  1000 Winter Street
                                  Suite 3350
                                  Waltham, MA 02154

                                  By: Polaris Venture Management Co., LLC,
                                      Its General Partner

                                  By: /s/ William E. Bilodeau
                                      ------------------------------------------
                                      Name: William E. Bilodeau
                                      Title: Attorney-in-fact

                                  POLARIS VENTURE PARTNERS FOUNDERS' FUND, L.P.
                                  1000 Winter Street
                                  Suite 3350
                                  Waltham, MA 02154

                                  By: Polaris Venture Management Co., LLC
                                      Its General Partner

                                  By: /s/ William E. Bilodeau
                                      ------------------------------------------
                                      Name: William E. Bilodeau
                                      Title: Attorney-in-fact
<PAGE>
                                  BANCBOSTON VENTURES, INC.
                                  175 Federal Street, 10th Floor
                                  Boston, MA 02110

                                  By: /s/ John B. McCormick
                                      ------------------------------------------
                                      Name: John B. McCormick
                                      Title: Vice President
<PAGE>
                                  PRIVATE EQUITY PORTFOLIO FUND II, LLC
                                  c/o BancBoston Capital
                                  175 Federal Street, 10th Floor
                                  Boston, MA 02110

                                  By: Fleet National Bank NA,
                                      Its Manager

                                  By: /s/ John DeSisto
                                      ------------------------------------------
                                      Name: John DeSisto
                                      Title: Vice President
<PAGE>
                                  TECHNOLOGY FUNDING PARTNERS III, L.P.,
                                  A Delaware Limited Partnership
                                  c/o Debra Giambruno
                                  1107 Investment Blvd., Suite 180
                                  El Dorado Hills, CA 95762

                                  By: Technology Funding, Inc.
                                      Managing General Partner

                                  By: /s/ Peter F. Bernardoni
                                      ------------------------------------------
                                      Vice President

                                  TECHNOLOGY FUNDING VENTURE
                                  PARTNERS V, AN AGGRESSIVE GROWTH FUND L.P.
                                  c/o Debra Giambruno
                                  1107 Investment Blvd., Suite 180
                                  El Dorado Hills, CA 95762

                                  By: Technology Funding, Inc.
                                      Managing General Partner

                                  By: /s/ Peter F. Bernardoni
                                      ------------------------------------------
                                      Vice President
<PAGE>
                                  DEBAR INVESTMENT PARTNERSHIP LLP
                                  c/o Sue DeCarlo
                                  5 Misty Brook Lane
                                  New Fairfield, CT 06812

                                  By: /s/ Sue DeCarlo
                                      ------------------------------------------
                                      Name: Sue DeCarlo
                                      Title: Managing Member

<PAGE>

                                  AUDAX PRIVATE EQUITY FUND, L.P.
                                  c/o Audax Group
                                  101 Huntington Ave.
                                  Floor 24
                                  Boston, MA 02199

                                  By:     Audax Private Equity Business, LLC
                                          Its General Partner

                                  By:     Audax Private Equity Business, L.P.,
                                          Its Managing Member

                                  By:     /s/ Steven F. Kaplan
                                          ------------------------
                                           Name: Steven F. Kaplan
                                           Title:

                                  AUDAX CO-INVEST, L.P.
                                  c/o Audax Group
                                  101 Huntington Ave.
                                  Floor 24
                                  Boston, MA 02199

                                  By:     101 Huntington Holdings, LLC
                                          Title: General Partner

                                  By:     /s/ Steven F. Kaplan
                                          ---------------------------
                                          Name: Steven F. Kaplan
                                          Title: Authorized Signatory

<PAGE>

                                  AUDAX TRUST CO-INVEST, L.P.
                                  c/o Audax Group
                                  101 Huntington Ave.
                                  Floor 24
                                  Boston, MA 02199

                                  By:     101 Huntington Holdings, LLC
                                          Title: General Partner

                                  By:     /s/ Steven F. Kaplan
                                          ---------------------------
                                          Name: Steven F. Kaplan
                                          Title: Authorized Signatory

                                  AFF CO-INVEST, L.P.
                                  c/o Audax Group
                                  101 Huntington Ave.
                                  Floor 24
                                  Boston, MA 02199

                                  By:     101 Huntington Holdings, LLC
                                          Title: General Partner

                                  By:     /s/ Steven F. Kaplan
                                          ---------------------------
                                          Name: Steven F. Kaplan
                                          Title: Authorized Signatory

<PAGE>

                                  AUDAX SPECIAL PURPOSE CO-INVEST, L.P.
                                  c/o Audax Group
                                  101 Huntington Ave.
                                  Floor 24
                                  Boston, MA 02199

                                  By:     101 Huntington Holdings, LLC
                                          Title: General Partner

                                  By:     /s/ Steven F. Kaplan
                                          ---------------------------
                                          Name: Steven F. Kaplan
                                          Title: Authorized Signatory

<PAGE>

                                  THOMAS WEISEL CAPITAL PARTNERS, L.P.
                                  c/o Derek Lemke-von Ammon, Executive
                                  Committee, Director of Private Equity
                                  c/o One Montgomery Street, Suite 3700
                                  San Francisco, California 94104

                                  By:  Thomas Weisel Capital Partners LLC,
                                       its general partner

                                  By:  Thomas Weisel Partners Group LLC,
                                       its managing member

                                  By:  /s/ Derek Lemke-von Ammon
                                       ------------------------------------
                                       Derek Lemke-von Ammon
                                       Attorney-in-fact

                                  TWP CEO FOUNDERS CIRCLE (AI), L.P.
                                  c/o Derek Lemke-von Ammon, Executive
                                  Committee, Director of Private Equity
                                  c/o One Montgomery Street, Suite 3700
                                  San Francisco, California 94104

                                  By:  Thomas Weisel Capital Partners LLC,
                                       its general partner

                                  By:  Thomas Weisel Partners Group LLC,
                                       its managing member

                                  By:  /s/ Derek Lemke-von Ammon
                                       -----------------------------------
                                       Derek Lemke-von Ammon
                                       Attorney-in-fact

<PAGE>

                                  TWP CEO FOUNDERS CIRCLE (QP), L.P.
                                  c/o Derek Lemke-von Ammon, Executive
                                  Committee, Director of Private Equity
                                  c/o One Montgomery Street, Suite 3700
                                  San Francisco, California 94104

                                  By:  Thomas Weisel Capital Partners LLC,
                                       its general partner

                                  By:  Thomas Weisel Partners Group LLC,
                                       its managing member

                                  By:  /s/ Derek Lemke-von Ammon
                                       -------------------------------------
                                       Derek Lemke-von Ammon
                                       Attorney-in-fact

                                  THOMAS WEISEL CAPITAL PARTNERS (DUTCH), L.P.
                                  c/o Derek Lemke-von Ammon, Executive
                                  Committee, Director of Private Equity
                                  c/o One Montgomery Street, Suite 3700
                                  San Francisco, California 94104

                                  By:  Thomas Weisel Capital Partners LLC,
                                       its general partner

                                  By:  Thomas Weisel Partners Group LLC,
                                       its managing member

                                  By:  Thomas Weisel Capital Partners Group
                                       LLC, its managing member

                                  By:  /s/ Derek Lemke-von Ammon
                                       ------------------------------------
                                       Derek Lemke-von Ammon
                                       Attorney-in-fact

<PAGE>

                                  THOMAS WEISEL CAPITAL PARTNERS
                                  (DUTCH II), L.P.
                                  c/o Derek Lemke-von Ammon, Executive
                                  Committee, Director of Private Equity
                                  c/o One Montgomery Street, Suite 3700
                                  San Francisco, California 94104

                                  By:  Thomas Weisel Capital Partners
                                       (Dutch), LLC, its general partner

                                  By:  Thomas Weisel Capital Partners LLC,
                                       its managing member

                                  By:  Thomas Weisel Capital Partners Group
                                       LLC, its managing member

                                  By:  /s/ Derek Lemke-von Ammon
                                       ------------------------------------
                                       Derek Lemke-von Ammon
                                       Attorney-in-fact

                                  THOMAS WEISEL CAPITAL PARTNERS EMPLOYEE
                                  FUND, L.P.
                                  c/o Derek Lemke-von Ammon, Executive
                                  Committee, Director of Private Equity
                                  c/o One Montgomery Street, Suite 3700
                                  San Francisco, California 94104

                                  By:  Thomas Weisel Capital Partners LLC,
                                       its general partner

                                  By:  Thomas Weisel Partners Group LLC,
                                       its managing member

                                  By:  /s/ Derek Lemke-von Ammon
                                       -------------------------------------
                                       Derek Lemke-von Ammon
                                       Attorney-in-fact

<PAGE>

                                  TWP 2000 CO-INVESTMENT FUND, L.P.
                                  c/o Derek Lemke-von Ammon, Executive
                                  Committee, Director of Private Equity
                                  c/o One Montgomery Street, Suite 3700
                                  San Francisco, California 94104

                                  By:  Thomas Weisel Capital Partners LLC,
                                       its general partners

                                  By:  Thomas Weisel Partners Group LLC,
                                       its managing member

                                  By:  /s/ Derek Lemke-von Ammon
                                       ------------------------------------
                                       Derek Lemke-von Ammon
                                       Attorney-in-fact

<PAGE>

                                  DINTERSMITH FAMILY LIMITED PARTNERSHIP
                                  c/o Charles River Ventures
                                  Bay Colony Corporate Center
                                  1000 Winter Street
                                  Suite 3300
                                  Waltham, MA 02154

                                  By:  /s/ Ted R. Dintersmith
                                       ---------------------------------------
                                       Name:  Ted Dintersmith
                                       Title:    Managing Partner

<PAGE>

                                  ROBERT S. LANGER
                                  98 Montvale Road
                                  Newton, MA 02459

                                   /s/ Robert S. Langer
                                  --------------------------

<PAGE>

                                  KD VENTURES LLC
                                  c/o 26 Turtle Rock Court
                                  Tiburon, CA 94920

                                  By:  /s/ David Norman
                                       ---------------------------------------
                                       Name: David Norman
                                       Title:   Director

<PAGE>

                                  FOR THE PURPOSES OF SECTIONS 1, 3.4 AND 4
                                  ONLY

                                  SHERRI C. OBERG
                                  157 Bristol Road
                                  Wellesley, MA 02181

                                  /s/ Sherri C. Oberg
                                  --------------------------------

<PAGE>

                                                                      Schedule A

                                  Investors

      Thomas Weisel Capital Partners, L.P.
      TWP CEO Founders Circle (AI), L.P.
      TWP CEO Founders Circle (QP), L.P.
      Thomas Weisel Capital Partners (Dutch), L.P.
      Thomas Weisel Capital Partners (Dutch II), L.P.
      Thomas Weisel Capital Partners Employee Fund, L.P.
      TWP 2000 Co-Investment Fund, L.P.
      MVI Medical Venture Investments Limited
      Diamond Capital Management, Inc.
         (as Investment Advisor for the Retirement Program Plan for Employees
         of Union Carbide Corporation and its Participating Subsidiary
         Companies)
      Audax Private Equity Fund, L.P.
      Audax Co-Invest, L.P.
      Audax Trust Co-Invest, L.P.
      AFF Co-Invest, L.P.
      Audax Special Purpose Co-Invest, L.P.
      DeBar Investment Partnership LLP
      Prism Venture Partners I, L.P.
      The CIT Group/Equity Investments, Inc.
      ABS Employees' Venture Fund L.P.
      Bank of America Ventures
      BA Venture Partners II
      Alta V Limited Partnership
      Customs House Partners
      Polaris Venture Partners, L.P.
      Polaris Venture Partners Founders' Fund, L.P.
      The Venture Capital Fund of New England III, L.P.
      Trustees of Boston University
      BancBoston Ventures, Inc.
      Private Equity Portfolio Fund II, LLC
      Technology Funding Venture Partners V, An Aggressive Growth Fund, L.P.
      Technology Medical Partners I, L.P.
      Technology Funding Partners III, L.P.
      Dintersmith Family Limited Partnership
      Robert S. Langer
      KD Ventures LLC
      A.R. Levinson Trust No. 1, dated July 15, 1990, as amended
      Alexandria Real Estate Equities, L.P.
      GATX Ventures, Inc.
      Venture Lending & Leasing III, Inc.<PAGE>
                                                                   Exhibit 10.22

[CONFIDENTIAL TREATMENT REQUESTED] /*/ INDICATES MATERIAL THAT HAS BEEN OMITTED
AND FOR WHICH CONFIDENTIAL TREATMENT HAS BEEN REQUESTED. ALL SUCH OMITTED
MATERIAL HAS BEEN FILED WITH THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
RULE 406 PROMULGATED UNDER THE SECURITIES ACT OF 1933, AS AMENDED.

                                                                    CONFIDENTIAL

                                  CTM AGREEMENT

          THIS CTM AGREEMENT is made and entered into this 7th day of September,
2001 (the "Effective Date") by and between Hollister-Stier Laboratories LLC,
having an address at 3525 North Regal Street, Spokane, WA 99207
("Hollister-Stier") and Acusphere, Inc., having an address at University Park at
M.I.T., 38 Sidney Street, Cambridge, Massachusetts 02139 ("Client") (each
individually a "Party" and collectively the "Parties").

                                 WITNESSETH THAT

         WHEREAS, Hollister-Stier has expertise, personnel, and experience in
conducting formulation and/or finishing of pharmaceutical products and has the
appropriate facilities to manufacture such products and is interested in
providing such manufacturing services to client companies in the pharmaceutical
area; and

         WHEREAS, Client has a commercial interest in the manufacture of PLGA
Microspheres and AI-700 (hereinafter respectively the "Intermediate" and the
"Product") and is desirous of utilizing the services of Hollister-Stier in a
phased program whereby Hollister-Stier will perform the "CTM Program" for Client
related to Clinical Phase III supplies of the Intermediate and Product in
compliance with All Applicable Laws and Regulations. Hollister-Stier and Client
will negotiate in good faith to arrive at a mutually acceptable commercial
supply agreement for the Product.

         NOW THEREFORE, in consideration of the mutual covenants contained
herein, Hollister-Stier and Client hereby agree as follows:

                                    ARTICLE 1

                                   DEFINITIONS

         The following terms, whether used in the singular or plural, shall have
the meanings assigned to them below for purposes of this CTM Agreement:

         "All Applicable Laws and Regulations" shall mean all Federal, state and
local laws and regulations and, where applicable, guidance documents promulgated
by the FDA and being currently utilized within the pharmaceutical industry to
manufacture the applicable type of products(s) that apply to the Services being
provided hereunder by Hollister-Stier, including, but not limited to, the
Federal Food, Drug, and Cosmetic Act (the "Act") as amended, and the regulations
promulgated thereunder, and the requirements of other domestic or foreign
governmental authorities made known to Hollister-Stier by Client, as all of such
laws, regulations or requirements may be amended or reenacted from time to time.

                                     Page 1
<PAGE>

         "Affiliate" shall mean any corporation or non-corporate entity which
directly or indirectly controls, is controlled by, or is under common control
with a Party. A corporation or non-corporate entity shall be regarded as in
control of another corporation if it owns or directly or indirectly controls at
least fifty percent (50%) of the voting stock of the other corporation or (a) in
the absence of the ownership of at least fifty percent (50%) of the voting stock
of a corporation or (b) in the case of a non-corporate entity, the power to
direct or cause the direction of the management and policies of such corporation
or non-corporate entity, as applicable.

         "Agreement" means this agreement, as it may from time to time be
supplemented or modified by written amendment(s) signed by the parties.

         "Batch" means a [CONFIDENTIAL TREATMENT REQUESTED] /*/ Unit size batch
of Product. One (1) batch of Product requires [CONFIDENTIAL TREATMENT REQUESTED]
/*/ of the Intermediate. [CONFIDENTIAL TREATMENT REQUESTED] /*/

         "cGMP Regulation" means Current Good Manufacturing Practices and
Quality Systems Regulations, as defined from time to time under the Act, as
codified in 21 CFR parts 200 and 211 and any guidelines or guidances promulgated
by the FDA and being currently utilized within the pharmaceutical industry to
manufacture the applicable type of products(s).

         "Chemicals and Materials" means the chemicals (other than the
Intermediate), and other materials such as vials required to manufacture and
bulk package the Product in accordance with the Product Specifications.

         "Client's Technology Package" means such technical information to be
supplied by Client to Hollister-Stier to permit Hollister-Stier to carry out its
obligations hereunder, including but not limited to, Client's raw material and
manufacturing component specifications, Intermediate and Product Specifications;
manufacturing and analytical testing equipment provided to Hollister-Stier by
Client, manufacturing equipment Installation Qualification (IQ) and Operation
Qualification (OQ) protocols, manufacturing and analytical testing equipment
standard operating procedures (SOP's), including cleaning procedures; analytical
method validation reports and analytical testing method transfer protocols
developed in conjunction with Hollister-Stier which detail the specific
analytical testing methods to be used and the acceptance criteria
Hollister-Stier must satisfy to be qualified to perform such analytical testing
methods; manufacturing filter validation reports; Process Simulation
(Intermediate) / Media Fill (Product) Manufacturing Batch Production Records,
Intermediate and Product Manufacturing Batch Production Records; Intermediate
and Product Storage specifications, and Product bulk shipping and label
specifications.

         "CTM" means Clinical Trial Material (product) to be used for clinical
trials, as opposed to product to be used for commercial sale.

         " CTM Program" shall have the meaning set forth in Sections 2.1 and 2.9
of this CTM Agreement.

                                     Page 2
<PAGE>

         "CTM Program Deliverables" means those deliverables as set forth in
Section 2.9 of this CTM Agreement. Included are specific confirmation,
qualification and validation activities related to the CTM Program as set forth
in Exhibit 1 and Exhibit 3 of this Agreement.

         "CTM Program Facilities" means Hollister-Stier's manufacturing facility
located in Spokane, WA.

         "Drug Substance" means the perfluorocarbon gas that is used in the
final processing step of the Product.

         "FDA" means the United States Food and Drug Administration or any
successor organization and all agencies under their direct control.

         "Information" shall have the meaning set forth in Section 4.1 of this
CTM Agreement.

         "Intermediate" means with respect to the Product, PGLA Microspheres,
but shall not include other Chemicals and Materials.

         "Manufacturing Process" means the process for manufacturing the
Intermediate and Product which is confirmed during the Manufacturing Program by
Hollister-Stier under Sections 2.1 and 2.9 hereof using Client's Technology
Package as herein defined.

         "Product" for the purposes of this CTM Agreement means Clinical Phase
III material of AI-700.

         "Schedule" means the project timeline, milestones and deliverables as
set forth in Exhibit 3 of this Agreement.

         "Specifications" means the specifications for the Intermediate and
Product which will be attached hereto as Exhibit 2 of this CTM Agreement and
made a part hereof, as determined and agreed upon in accordance with the CTM
Program using analytical methodology set forth therein, as such specifications
may be amended from time to time by mutual agreement of the Parties.

         "Third Party" means any party other than Client, Hollister-Stier and
their respective Affiliates.

         "Unit" means a [CONFIDENTIAL TREATMENT REQUESTED] /*/fill of Product in
a [CONFIDENTIAL TREATMENT REQUESTED] /*/vial.

                                     Page 3
<PAGE>

                                    ARTICLE 2

                                   CTM PROGRAM

         2.1 Program Definition. Hollister-Stier shall, in compliance with All
Applicable Laws and Regulations, carry out the manufacturing program outlined in
Exhibit 1 of this Agreement hereto including any modifications and additions
thereto agreed upon by the Parties (" CTM Program") and in accordance with the
Schedule as set forth in Exhibit 3 of this Agreement shall (i) confirm the
Manufacturing Process, including the confirmation, qualification and validation
activities as specified in Exhibit 1 and Exhibit 3 of this Agreement, (ii)
confirm the Specifications for manufacturing the Intermediate and Product, (iii)
manufacture Batches in accordance with the requirements set forth in Exhibit 1
of this Agreement, and (iv) confirm the analytical methodology used to test the
Intermediate and Product for compliance with the Specifications in accordance
with the acceptance criteria defined in analytical testing method transfer
protocols developed in conjunction with the Client. Hollister-Stier agrees to
work with Client to attempt to minimize the number of Development (Simulation)
Batches required prior to the manufacturing of aseptic process validation and
manufacturing of CTM Batches. The CTM Program shall identify all documentation
(including regulatory documentation) and other deliverables to be provided by
Hollister-Stier to Client pursuant to this Agreement and appended hereto as
Exhibit 4 ("the Documentation") of this Agreement. Hollister-Stier shall use its
commercially reasonable best efforts to complete the CTM Program in a timely
fashion in accordance with the Schedule agreed upon by the Parties and set forth
in Exhibit 3 of this Agreement. If Hollister-Stier is unable to complete any
stage of the CTM Program in the agreed times, it shall immediately notify
Client, in writing, of the delay, and the reason therefor. Hollister-Stier shall
negotiate with Client a mutually acceptable date of completion for the
respective stage of the CTM Program, and Hollister-Stier shall use its
commercially reasonable best efforts to complete the CTM Program within such
newly agreed upon time.

         2.2 Facilities; Staffing; Supplies; Equipment

            (i)    Renovations to the CTM Program Facilities are required to
perform the CTM program. Such renovations will provide Client with CTM and early
commercial scale-up capability for manufacturing the Intermediate. The
renovations will create a manufacturing area dedicated to Client. Excess
capacity of this dedicated area not utilized by Client may be used by
Hollister-Stier upon written approval from Client. Such approval will not be
unreasonably withheld. Client's equipment, as defined in Article 2, Section
2.2(iii), may not be used by other Hollister-Stier clients.

            (ii)   Hollister-Stier shall maintain at all times sufficient
staffing, supplies and equipment necessary for it to perform the CTM Program in
accordance with the terms of this Agreement. Client, in accordance with this
Agreement, shall provide and/or disclose to Hollister-Stier certain materials,
equipment and know-how, defined as the Client's Technology Package.

                                     Page 4
<PAGE>

            (iii)   Equipment. As part of the consideration for the CTM Program
provided hereunder, Client shall provide Hollister-Stier with the use of certain
analytical and manufacturing equipment ("the Equipment") as listed in Exhibit 5
of this Agreement.

                  (a)   During the term of this CTM Agreement, Client shall, at
its expense and in a timely manner, deliver the Equipment to Hollister-Stier for
installation and use solely in performing the CTM Program. The Parties shall
cooperate in the installation, calibration, confirmation, qualification,
validation, maintenance, cleaning and handling of the Equipment. As and to the
extent reflected in Exhibits 1 and 9 of this Agreement hereto, the calibration
of the Equipment will be at Hollister-Stier's cost, but Client shall have the
right to review and approve all installation, calibration, confirmation,
qualification, validation, maintenance, operation and cleaning procedures and
data for the Equipment as stated in Exhibit 1 of this Agreement. Costs for
maintenance and any requalification/revalidation of the Equipment during the
term of this Agreement shall be borne by Hollister-Stier except for such costs
which are associated with the condition of the Equipment when it was delivered
to Hollister-Stier, which costs shall be borne by Client. During the term of
this Agreement, the Equipment shall be exclusively dedicated to the performance
of the CTM Program.

                  (b)   At all times Client shall retain all legal and equitable
title to the Equipment. While the Equipment is located at Hollister-Stier's
premises, Hollister-Stier shall promptly notify Client of any damage to the
Equipment. Any cost to repair Equipment that is damaged while in the custody of
Hollister-Stier, except to the extent caused by Client, will be at
Hollister-Stier's sole cost and expense. Hollister-Stier must receive oral
approval from Client, which will not be unreasonably withheld, conditioned or
delayed, before any repairs to the Equipment are performed. Hollister-Stier will
provide timely, written documentation to Client detailing the repairs made to
the Equipment. Upon Client's written request, or any termination or expiration
of this Agreement, the Equipment and Equipment-related documentation (including
all calibration certificates and reports, use and cleaning logs, confirmation,
qualification, validation and maintenance documents) shall be promptly returned
to Client in good condition, usual wear and tear excepted. Hollister-Stier shall
make its premises and personnel available during normal business hours to assist
with the removal and return of the Equipment, along with all Equipment-related
documentation. Client shall be responsible for all costs and expenses of such
removal as set forth in Section 8.6 hereof. The Parties shall reasonably
cooperate with regard to the restoration of the CTM Program Facilities. While
the Equipment is located in the Premises, Hollister-Stier shall" (i) at its sole
expense, safeguard and care for the Equipment, subject to normal wear and tear,
(ii) not grant any person a security interest, lien or any other rights or
interest in or to the Equipment; and (iii) not remove, deface, alter, obscure or
obliterate any mark, tag or other information or identification or statement of
ownership placed on the Equipment by Client.

         2.3 Program Cost. The parties have defined the costs that are to be
incurred during the execution of this CTM Program, such costs are set forth in
Exhibit 1 and 9 hereof. Such costs ("Cost") have been estimated based on
anticipated manpower and overhead requirements for the

                                     Page 5
<PAGE>

tasks set forth in Exhibit 1 and 9 of this Agreement and the anticipated cost of
Chemicals and Materials, but excluding the cost of polymer, phospholipid and
perfluorocarbon raw materials, all of which shall be procured by Client and
provided by Client to Hollister-Stier at Client's sole expense. Client shall pay
or reimburse Hollister-Stier for the costs described in Exhibit 1 and 9 in the
amounts set forth in Section 2 of Exhibit 9 hereto and in accordance with the
procedures set forth in Exhibit 9 and Section 2.4 below. In addition, Client
shall, for such expenses and costs that are expressly authorized in writing in
advance by Client, separately pay Hollister-Stier, on an as-costs-are-incurred
basis in accordance with Section 2.4, (i) for all reasonable and necessary
travel and lodging expenses incurred in the performance of this Agreement which
have been requested or approved by Client, (ii) for Hollister-Stier's cost of
auditing any supplier of Chemicals or Materials not currently on
Hollister-Stier's list of approved suppliers, and (iii) Hollister-Stier's cost
for any specialized equipment or tooling associated with equipment changes
required at the Facility to manufacture the Product. In the event Client and
Hollister-Stier agree that additional manufacturing activities are necessary to
complete the CTM Program, the Cost shall be negotiated in good faith by the
Parties.

         2.4 Invoices and Payment. Hollister-Stier will submit invoices to
Client reflecting the work completed in accordance with applicable milestones,
such milestones ("the Milestones") being described in Exhibit 9. Client shall
pay all uncontested Hollister-Stier invoices issued pursuant to this Agreement
within thirty (30) days of the dates thereof. Client shall, within this thirty
(30) day period notify Hollister-Stier regarding any contested amounts or
questions regarding an invoice or invoice item. Hollister-Stier agrees to
respond to requests by Client to clarify questions on any invoice or invoice
item, and Client agrees that it will use its best efforts to resolve contested
invoice items in a timely fashion. Hollister-Stier acknowledges and agrees that
Client is not obligated to pay such contested amounts otherwise due and payable
within the thirty (30) day period until such time as the contested issues are
resolved to the satisfaction of both Parties, and that Client will not be
subject to any penalty or finance charge for such withheld payments. All
payments due hereunder to Hollister-Stier shall be sent to Hollister-Stier at
the times set forth herein by wire transfer of funds via the Federal Reserve
Wire Transfer System to such financial institution as Hollister-Stier may
designate to Client in writing from time to time in accordance with Section 10.1
hereof. Prior to the value date of each transfer, Client shall notify such
person as Hollister-Stier may designate to Client from time to time in
accordance with Section 10.1 hereof. Not withstanding the foregoing, if Client
does not raise at least [CONFIDENTIAL TREATMENT REQUESTED] /*/ in new funds
prior to the scheduled delivery date of any CTM batch then Client shall pay for
such batch upon delivery.

         All amounts not paid when due, with the exception of contested invoices
as described herein, shall bear interest from the due date at the rate of one
and one-half percent (1.5%) per month (or such other percentage, if lower, as
shall not exceed the maximum rate permitted by law).

         The Cost does not include sales, use, consumption, or excise taxes of
any taxing authority. Hollister-Stier shall notify Client of any such tax at the
execution of this Agreement,

                                     Page 6
<PAGE>

or upon learning that such taxes are applicable to any of the Product or
Services contemplated by this Agreement. The amount of such taxes, if any, will
be added to the Cost and shall be reflected in the invoices submitted to Client
by Hollister-Stier pursuant to this Agreement. Client shall pay the amount of
such taxes to Hollister-Stier in accordance with the payment provisions of this
Agreement.

         2.5 Client's Responsibilities. To assist Hollister-Stier in its
performance of this Agreement, Client shall provide Hollister-Stier, in a timely
fashion, with all relevant information, documentation and data in the Client's
Technology Package and as set forth in Exhibit 1 of this Agreement necessary or
appropriate for Hollister-Stier's performance hereunder, including without
limitation the information, documentation and data set forth in Exhibit 1 of
this Agreement. Client shall ensure that all Chemicals and Materials supplied to
Hollister-Stier by or on behalf of Client (as may be set forth in Exhibit 1 of
this Agreement) are suitable for use under this Agreement, comply with All
Applicable Laws and Regulations (including without limitation those relating to
the import of such materials) and receive all required governmental and
regulatory approvals, including without limitation customs and FDA approvals. If
requested by Hollister-Stier to provide the support or information referred to
in the first sentence of this paragraph, Client shall provide such support or
information (or a reasonable explanation for any delay and a projected date by
which such support or information will be provided) within five (5) business
days of Hollister-Stier's request. In the event Client is to review or approve
any information, documentation, data or samples prepared or supplied by or on
behalf of Client, it shall complete such review and approval process within five
(5) business days, unless additional time is requested by Client based upon a
reasonable explanation provided to Hollister-Stier within such five (5) day
period. Client shall cooperate with Hollister-Stier in the performance of this
CTM Agreement and shall deal honestly and in good faith with Hollister-Stier.

         2.6 Hollister-Stier's Responsibilities. Hollister-Stier shall provide
Client, in a timely fashion, with all relevant information, documentation and
data necessary or appropriate for Client's performance hereunder, including
without limitation any Hollister-Stier information, documentation and/or other
materials as may be set forth in Exhibits 1 and 4 of this Agreement.
Hollister-Stier shall ensure that all Chemicals and Materials supplied by
Hollister-Stier on behalf of the Manufacturing Program (as may be set forth in
Exhibit 1 of this Agreement) are suitable for use under this Manufacturing
Agreement, comply with All Applicable Laws and Regulations (including without
limitation those relating to the import of such materials) and receive all
required governmental and regulatory approvals, including without limitation
customs and FDA approvals. If covered by Exhibits 1 and 4 of this Agreement
hereof, and if, requested by Client to provide the support or information
referred to in the first sentence of this paragraph, Hollister-Stier shall
provide such support or information (or a reasonable explanation for any delay
and a projected date by which such support or information will be provided)
within five (5) business days of Client's request. In the event Hollister-Stier
is to review or approve any information, documentation, data or other materials
prepared or supplied by or on behalf of Hollister-Stier, it shall complete such
review and approval process within five (5) business days, unless additional
time is requested by Hollister-Stier based upon a reasonable explanation

                                     Page 7
<PAGE>

provided to Client within such five (5) day period. Hollister-Stier shall
cooperate with Client in the performance of this Agreement and shall deal
honestly and in good faith with Client.

         2.7 Cooperation. Hollister-Stier shall provide all reasonable
cooperation with Client's representatives in order that Client may from time to
time confirm Hollister-Stier's compliance with the provisions of this Agreement,
including, but not limited to, Hollister-Stier's due and reasonable care in the
storage of Chemical and Materials and components, Intermediate and Product
Batches, and Hollister-Stier's compliance with All Applicable Laws and
Regulations, and any applicable guidance documents or other standards which are
agreed upon by the Parties.

         2.8 Manufacturing. (i) Upon the completion of each batch of the
Intermediate and Product, Hollister-Stier shall submit copies (certified as
accurate and complete by authorized Hollister-Stier Quality Assurance personnel)
of all documents and test data for that batch, including documents and test data
pertinent to the CTM Program facilities and utilities involved in the
manufacture of that batch as set forth in Section 2.9 of this Agreement.

         (ii) Prior to initiating any aseptic process validation and CTM Batch
manufacturing, the Parties shall prepare and agree upon Master Batch Production
and Control Records for the Intermediate and Product, which when prepared and
agreed upon by the Parties shall be appended as Exhibit 6 of this Agreement and
deemed incorporated into the Specifications.

         (iii) Prior to initiating any aseptic process validation and CTM Batch
manufacturing, the Parties shall prepare and agree upon Master Quality Control
analytical testing methods and procedures for testing the Chemicals and
Materials, Intermediate and Product for conformance to the Specifications, which
when prepared and agreed upon by the Parties shall be appended as Exhibit 7 of
this Agreement. In addition, the Parties shall prepare and agree upon Master
Quality Control analytical testing method transfer protocols that detail the
specific analytical testing methods to be transferred and the acceptance
criteria Hollister-Stier must satisfy to be qualified to perform such analytical
testing methods, which when prepared and agreed upon by the Parties shall be
appended as Exhibit 8 of this Agreement.

         (iv) Prior to initiating any aseptic process validation and CTM Batch
manufacturing, Hollister-Stier will provide Client with a list of all applicable
standard operating procedures, including revision numbers, for the equipment,
utilities, facilities or other systems related to the manufacturing, inspection,
testing, bulk packaging and storage of the Intermediate and Product. Client will
review all applicable standard operating procedures and any revisions thereto
related to the equipment, utilities, facilities or other systems related to the
manufacturing, inspection, testing, bulk packaging and storage of the
Intermediate and Product.

                                     Page 8
<PAGE>

         2.9 Delivery of CTM Program Deliverables. In accordance with the
manufacturing milestones established by the Parties in Exhibits 1, 3 and 9 of
this Agreement, Hollister-Stier shall produce and deliver the CTM Program
Deliverables to Client. In all cases, unless otherwise directed in writing, CTM
Program Deliverables shall be: (i) delivered in single shipments at the option
and request of Client using a carrier expressly approved in writing by the
Parties, and pursuant to Client's shipping requirements as defined in Exhibit 1
of this Agreement and using Hollister-Stier's bulk shipping container(s), and at
Client's expense, three (3) to six (6) QA released, unlabeled, bulk packaged
Batches of Product produced in accordance with the CTM Program. Hollister-Stier
shall retain appropriate representative samples, as agreed upon in writing by
the Parties, from each batch of Intermediate and Product for record keeping,
testing and regulatory purposes. The amount of samples retained will be twice
the quantity required to carry out all of the tests required, with the exception
of sterility and LAL testing, to determine if the Intermediate and Product meet
Specifications; (ii) accompanied by a certificate executed by authorized
Hollister-Stier Quality Assurance personnel that such CTM Program Deliverables
meet applicable Specifications and were otherwise produced in accordance with
this CTM Agreement, and all pertinent test data and results; (iii) accompanied
by a copy of the Manufacturing Batch Production Records for the delivered batch
of Product and the batch of Intermediate used to manufacture such batch of
Product, all of which are to be certified and stamped by Hollister-Stier Quality
Assurance personnel as being accurate and complete and in accordance with this
CTM Agreement. Hollister-Stier may, at its sole discretion, transmit the
information specified in subsection (iii) separately from other project
deliverables, but Hollister-Stier acknowledges that such separate transmission
shall be made at or about the time of the shipment of other Program Deliverables
as set forth in this section.

         2.10 Quality Control. Before authorizing shipment of any batch of the
Product, Hollister-Stier shall conduct and complete quality control testing of
the Intermediate and Product as set forth in Exhibit 1 and 2 hereto and ensure
that the Batches: (i) were manufactured and tested in accordance with the Master
Batch Production and Control Records, Master Quality Control analytical testing
methods and All Applicable Laws and Regulations and (ii) meet applicable
Specifications. Hollister-Stier shall immediately notify Client of: (i) any
known deviation and/or errors by Hollister-Stier personnel from procedures set
forth in the Master Manufacturing Batch Production and Control Records ("Process
Deviation"), equipment, procedures, QC analytical testing methods and
procedures, utilities, facility or other systems, or other breach of
Hollister-Stier's obligations and of (ii) any "Out-of-Specification" test data
or results pertaining to any testing carried out in relation to the performance
of the CTM Program, operation of the CTM Program Facilities involved in the
manufacturing of the Intermediate and/or Product or completion of the CTM
Program Deliverables. Hollister-Stier shall obtain Client's written approval
prior to implementing any further manufacturing, retesting or resampling in
connection with such deviation, error or Out-of-Specification test data or
result for the Intermediate and Product, except for such further manufacturing,
retesting or resampling procedures specifically authorized under Client approved
procedures in effect prior to the occurrence of the deviation, error or the
Out-of-Specification test data or result. Except as

                                     Page 9
<PAGE>

provided in a written manufacturing procedure approved in writing by Client,
Hollister-Stier acknowledges and agrees that it shall not rework or reprocess
any non-conforming raw or in-process materials, Intermediate or Product.
Deviations undertaken by Hollister-Stier, unless expressly approved in advance
by Client, remain the responsibility of Hollister-Stier. Any failure of any
aseptic validation Batches or Batches of Intermediate and Product resulting from
such deviations and/or errors by Hollister-Stier personnel shall be the
responsibility of Hollister-Stier. Hollister-Stier, at its total expense, will
be responsible for replacing a batch of product that is rejected because of such
deviations and/or errors by Hollister-Stier personnel. Hollister-Stier is
responsible for formally investigating and documenting any failures to follow or
deviations from the Master Manufacturing Batch Production and Control Records or
QC analytical testing methods or procedures, any test or in-process test which
fails to meet Specifications and any failures of the equipment, utilities,
facility or other systems used to manufacture the Intermediate and Product, in
accordance with Hollister-Stier's procedures and cGMP Regulations.

         2.11 Non-Conforming Intermediate or Product. (i) Client from time to
time may conduct verification testing of Batches of Intermediate or Product in
accordance with the Specifications ("Conformance Verification Testing"). Such
Conformance Verification Testing shall be initiated promptly upon receipt of any
Batches and shall be completed within thirty (30) days. Client shall have the
right to reject, and to revoke any acceptances for, any shipment or batch (and
all Batches made from such batch) of Intermediate or Product that fails to meet
the applicable Specifications (including stability where a stability
specification is established and failed because of a manufacturing deficiency)
and other requirements under this Agreement (including Intermediate and Product
determined not to have been manufactured in accordance with this Agreement.)

              (ii) All claims of non-conformance arising from the Conformance
Verification Testing, except for good cause, shall be deemed waived unless made
by the Client in writing and received by Hollister-Stier within forty-five (45)
days of Client's receipt of the documentation specified in Section 2.9.

              (iii) If, after its own analysis of the Intermediate or Product
batch(es), or other information, Hollister-Stier confirms the non-conformity,
Hollister-Stier shall manufacture and ship a replacement batch or Batches for
the non-conforming batch or shipment at its expense. If, after its own analysis,
Hollister-Stier does not confirm the non-conformity, the Parties shall in good
faith agree to retest the shipment or batch or otherwise in good faith attempt
to agree on a resolution of the issue. In the event that the Parties cannot
resolve the issue, the Parties shall submit the disputed shipment or batch to a
mutually agreed independent testing laboratory or other expert for testing and
review. That laboratory's or expert's finding shall be binding on the Parties,
absent manifest error.

              (iv) Hollister-Stier shall bear such expense of the independent
laboratory testing and other expert review if testing or expert review confirms
the non-conformity of the shipment or batch with applicable Specifications, and
Client shall bear such expenses otherwise. In the

                                    Page 10
<PAGE>

event that any shipment or batch is ultimately agreed or determined to not meet
the Specifications, Hollister-Stier shall at Client's election (a) use its best
efforts to promptly (but no longer than within sixty (60) days from the date of
such agreement or determination) manufacture and ship a replacement batch or
Batches for the non-conforming batch or shipment at its expense. Client shall
return, or cause its designee to return, any rejected or revoked shipment or
batch to Hollister-Stier if so instructed by Hollister-Stier, at
Hollister-Stier's expense. In the event that any shipment or batch is ultimately
agreed or found to meet the Specifications and other applicable requirements,
Client shall accept and pay for the shipment or batch.

         2.12 Modification. Hollister-Stier and Client may from time to time in
good faith negotiate amendments to the Attachments and Exhibits hereof in the
event that (i) Client's requirements change and, as a result, Client determines
that any requirements stated in these Exhibits are no longer required, (ii)
Client requires additional services, (iii) the standards or requirements with
respect to any described activities need to be changed, or (iv) either Party
determines that a modification is desirable. Any modification shall be effective
only when approved in writing by the Parties.

         2.13 Reporting/Transfer of Results. (i) Upon completion of the CTM
Program, Hollister-Stier will provide Client with a written report of the
results, which have been developed, compiled or learned during the course of the
CTM Program, including other relevant manufacturing documentation such as the
stability data package, all as more particularly described in Exhibit 1 of this
Agreement hereto. Hollister-Stier shall also (a) provide monthly written
reports, the content and format of said reports to be mutually agreed upon in
writing, detailing the status of the CTM Program, (b) respond timely to Client's
inquiries regarding the status of the CTM Program on an ongoing basis, and (c)
keep Client reasonably informed of interim results on an informal basis,
including if requested, periodic meetings at Hollister-Stier's facility to
discuss the CTM Program results and progress. (ii) In addition to the foregoing,
the parties shall appoint a Project Steering Committee consisting of four
persons, two appointed by each party. The Hollister-Stier representatives to the
Project Steering Committee shall consist of one member of senior management and
the individual directly responsible for managing the CTM Program for
Hollister-Stier. The Client and Hollister-Stier representatives responsible for
managing the CTM Program will confer regarding the status of the CTM Program by
telephone at minimum every two (2) weeks. The Project Steering Committee will
meet in person at least once per quarter during the term of the CTM Program, if
determined necessary by the Parties. The Project Steering Committee will be
responsible for overseeing the execution of the CTM Program and for approving
any changes related to the Program.

         2.14 Access. Client at its discretion may have its representatives
observe any performance of the CTM Program, including any equipment, facility,
qualification, analytical, manufacturing, inspection and bulk packaging
activities to provide appropriate technical support and to ensure compliance
with All Applicable Laws and Regulations. Hollister-Stier, at its cost, shall
provide Client's representatives carrying out such observations with reasonable
office space and telephone access.

                                    Page 11
<PAGE>

         2.15 Ownership of Tangible Materials Subject to Sections 2.16 and 2.17,
Client shall retain ownership of all information, documents and materials which
Client provides to Hollister-Stier in connection with the performance of the CTM
Program hereunder, and Client shall have full possession of, and all rights to
use, all reports, documents and other tangible materials which Hollister-Stier
provides to Client as part of the results of the CTM Program. Information,
documents and materials provided by the Client, and any copies thereof, shall be
returned to the Client by Hollister-Stier at the conclusion of the CTM Program.

         2.16 (a) Hollister-Stier Property. Client acknowledges that
Hollister-Stier possesses certain inventions, processes, know-how, trade
secrets, improvements, other intellectual properties and other assets, including
but not limited to procedures and techniques, computer technical expertise,
software, and certain technical expertise and conceptual expertise in the area
of drug processing and manufacturing, which have been independently developed by
Hollister-Stier or its Affiliates without the benefit of any information
provided by Client (collectively "Hollister-Stier Property"). Client and
Hollister-Stier agree that any Hollister-Stier Property or improvements thereto
which are used, improved, modified or developed by Hollister-Stier under or
during the term of this Agreement are the product of Hollister-Stier's technical
expertise possessed and developed by Hollister-Stier or its Affiliates prior to
or during the performance of this Agreement and are the sole and exclusive
property of Hollister-Stier or its Affiliates, as the case may be.

              (b) Acusphere Property. Hollister-Stier acknowledges that Client
possesses certain inventions, processes, know-how, trade secrets, improvements,
other intellectual properties and other assets, including but not limited to
procedures and techniques, computer technical expertise, software, and certain
technical expertise and conceptual expertise relating to the Intermediate and
Product, which have been independently developed by Client or its Affiliates
without the benefit of any information provided by Hollister-Stier (collectively
"Client Property"). Client and Hollister-Stier agree that any Client Property or
improvements thereto which are used, improved, modified or developed by Client
under or during the term of this Agreement are the product of Client's technical
expertise possessed and developed by Client or its Affiliates prior to or during
the performance of this Agreement and are the sole and exclusive property of
Client or its Affiliates, as the case may be.

         2.17 Ownership and Rights to Inventions and Technology. All inventions,
technology and information, whether patentable or not (other than those
described in Section 2.16(a), which shall be owned by Hollister-Stier pursuant
to Section 2.16(a)), conceived, reduced to practice or created by either party
and/or its agents during the performance of this Agreement ("Program
Technology"), shall be owned by the Client; provided, however, to the extent
that any such invention relates to production processes not related to the
manufacture of Product, the Client shall grant and hereby grants to
Hollister-Stier a royalty-free, non-exclusive, world-wide, irrevocable license
to practice such Program Technology in facilities owned, operated, licensed,
rented or otherwise controlled by Hollister-Stier. Client shall be responsible
for the costs of filing, prosecution and maintenance for patents and patent
applications on Program Technology

                                    Page 12
<PAGE>

and shall have full control over such filing, provided that the decision to
proceed with any such filing shall be solely at the discretion of the Client.

                                    ARTICLE 3

                       RIGHT OF NEGOTIATION TO MANUFACTURE

         3.1 Subject to rights which may be granted by Client to third parties
in connection with collaborative development and marketing arrangements, prior
to commencing negotiations with any third party regarding the commercial
manufacture of the Product, Client shall commence good faith negotiations
regarding the same with Hollister-Stier.

                                    ARTICLE 4

                                 CONFIDENTIALITY

         4.1 Definition. In carrying out the CTM Program it is recognized by
Hollister-Stier and Client that each may have to disclose to the other
information of a business or technical nature which is proprietary and
confidential to the disclosing Party (hereinafter ("Information")). Since both
Parties wish to assume that the Information is properly protected they hereby
agree as follows:

         4.2 Form of Disclosure. Information may be disclosed in either oral,
written or electronic form. For any Information to be deemed confidential by the
disclosing party, it will either be supplied in writing or electronically and
marked "CONFIDENTIAL" or, if supplied, orally (or electronically and not clearly
marked as "CONFIDENTIAL"), summarized in writing within thirty (30) days of
disclosure and marked "CONFIDENTIAL".

         4.3 Obligations. The receiving Party agrees to hold Information in
strict confidence for a period of five (5) years from receipt and to use it only
for the purposes under this Agreement. The receiving Party agrees not to
disclose the Information to any Third Party unless prior written authorization
has been obtained from the disclosing Party. These obligations shall not apply
to:

         (a) Information which, at the time of disclosure, is in the public
domain.

         (b) Information which, after disclosure, becomes a part of the public
domain by publication or otherwise, except by breach of this CTM Agreement by
the receiving Party.

         (c) Information which the receiving Party can demonstrate by its
written records was in the receiving Party's possession at the time of such
disclosure, and which was not acquired,

                                    Page 13
<PAGE>

directly or indirectly, from the disclosing Party.

         (d) Information which is lawfully disclosed to the receiving Party on a
non-confidential basis by a Third Party who is not obligated to the disclosing
Party or any other Third Party to retain such Information in confidence.

         (e) Information which results from research and development by the
receiving Party independent of such disclosure as shown by competent evidence.

         (f) Information which is required to be disclosed by legal process;
provided, in each case the Party so disclosing Information timely informs the
other Party and uses its best efforts to limit the disclosure and maintain
confidentiality to the extent possible and permits the other Party to attempt by
appropriate legal means to limit such disclosure.

                                    ARTICLE 5

                       HOLLISTER-STIER'S REPRESENTATIONS,
                            WARRANTIES AND COVENANTS

         Hollister-Stier represents, warrants and covenants to Client as
follows:

         5.1 Commercially Reasonable Best Efforts. Hollister-Stier shall use its
best efforts to perform the services contemplated hereunder in accordance with
the CTM Program and the CTM Program schedule, it being recognized, however, that
since the services are of a developmental or research nature, there can be no
guarantee that the CTM Program will be successfully completed, or successfully
completed within the contemplated time frame, despite Hollister-Stier's
commercially reasonable best efforts to do so. However, following the successful
completion of the required media fill Batches, Hollister-Stier will be
responsible for manufacturing the Intermediate and Product to Specifications
agreed upon by the Parties in writing. If Hollister-Stier is, for any reason,
unable to meet any contemplated time frames in the CTM Program, it shall
immediately notify Client of same, as provided in Section 2.1 hereof.

         5.2 Adherence to Specifications. Hollister-Stier shall, subject to
Section 5.1 hereof, produce the Product in accordance with the Specifications
for the Product.

         5.3 Qualified Personnel. Hollister-Stier shall engage and employ, train
and supervise professionally qualified personnel to safely and lawfully perform
the services contemplated hereunder.

         5.4 General. Hollister-Stier shall exercise all due and reasonable care
with regard to all raw materials, components, equipment, Intermediate and Drug
Product in its custody relating to the CTM Program. Hollister-Stier warrants
that it has the capacity, facilities, equipment, personnel, skill, know-how,
permits, approvals and licenses to perform the CTM Program.

                                    Page 14
<PAGE>

         5.5 Debarment. Hollister-Stier represents and warrants to Client that
it has neither been debarred nor subject to debarment and that it does not and
will not use in any capacity in connection with the CTM Program any person who
has been debarred pursuant to Section 306 of the Act or who is the subject of a
conviction (or an investigation or prosecution for an offense) described in this
section. Hollister-Stier agrees to inform Client immediately in writing if it or
any person who is performing the CTM Program hereunder on behalf of
Hollister-Stier is debarred or is the subject of a conviction described in
Section 306 of the Act or if any action, suit, claim, investigation or
proceeding is pending or, to the knowledge of Hollister-Stier, threatened
relating to debarment of Hollister-Stier or of any person performing the CTM
Program on behalf of Hollister-Stier hereunder.

         5.6 Disclaimer. THE FORGOING EXPRESS WARRANTIES, TOGETHER WITH THOSE
SET FORTH IN ARTICLE 6, ARE IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE, OR AGAINST INFRINGEMENTS, AND ALL OTHER WARRANTIES ARE
HEREBY DISCLAIMED AND EXCLUDED BY HOLLISTER-STIER.

                                    ARTICLE 6

                      GENERAL REPRESENTATION AND WARRANTIES

         Each Party represents, warrants and covenants to the other as follows:

         6.1 Power and Authorization. It has all requisite power and authority
(corporate and otherwise) to enter into this Agreement and has duly authorized
by all necessary action the execution and delivery hereof by the officer or
individual whose name is signed on its behalf below.

         6.2 No Conflict. Its execution and delivery of this Agreement and the
performance of its obligations hereunder do not and will not conflict with or
result in a breach of or a default under its organizational instruments or any
other agreement, instrument, order, law or regulation applicable to it or by
which it may be bound.

         6.3 Enforceability. This Agreement has been duly and validly executed
and delivered by it and constitutes its valid and legally binding obligation,
enforceable in accordance with its terms, except as enforcement may be limited
by bankruptcy, insolvency or other laws of general application relating to or
affecting the enforcement of creditors' rights and except as enforcement is
subject to general equitable principles.

         6.4 Compliance with Applicable Laws. Each Party shall comply with All
Applicable

                                    Page 15
<PAGE>

Laws and Regulations in connection with the performance of this Agreement.
Hollister-Stier acknowledges and agrees that, upon the written request of
Client, it shall comply with the laws and regulations of any foreign
governmental authorities as set forth in such written request.

         6.5 Financial Condition. It has delivered to the other Party financial
statements containing a balance sheet as of June 30, 2001 and related statements
of operation and cash flows for the six-month period then ended. Such financial
statements have been prepared in accordance with generally accepted accounting
principles (except that such statements do not contain footnotes and are subject
to year-end adjustments on audit which shall not in the aggregate be material)
and fairly present the financial condition of such Party as of such date. In
addition, it has disclosed to the other Party all facts relating to its
financial conditions and prospects that are material to an understanding of its
financial condition and prospects.

         6.6 Notification of Potential Liability. Each Party shall notify the
other in writing as soon as reasonably possible following any event, including
the receipt of any notice, warning, citation, finding, report or service of
process or the occurrence of any release, spill, upset or discharge of hazardous
wastes or substances, related to the CTM Program that could reasonably be
expected to give rise to liability on the part of the other Party under any law,
rule or regulation prescribed by a public authority or otherwise.

         6.7 Intellectual Property. Each Party represents and warrants to the
other that it owns and/or has full legal rights to use its respective Property
as described in Section 2.16 hereof in conjunction with and to the extent
required to perform all work required under this Agreement.

                                    ARTICLE 7

                                 INDEMNIFICATION

         7.1 Indemnification by Client. Client shall indemnify, defend and hold
Hollister-Stier, its Affiliates and their respective directors, officers,
employees, agents, successors and assigns harmless from and against any damages,
judgments, claims, suits, actions, liabilities, costs and expenses (including,
but not limited to, reasonable attorneys' fees) resulting from any Third Party
claims or suits arising solely out of (a) the use, handling, distribution,
marketing or sale of the Product (except to the extent caused solely by
Hollister-Stier's negligent acts or omissions or willful misconduct in its
performance of the CTM Program or the manufacture or bulk packaging of the
Product), (b) Client's uncured material breach of any of its warranties or
representations hereunder, or (c) Client's grossly negligent acts or omissions
or willful misconduct.

         7.2 Indemnification by Hollister-Stier. Except as otherwise provided in
Section 7.1 above, Hollister-Stier shall indemnify, defend and hold Client, its
Affiliates and their respective directors, officers, employees, agents,
successors and assigns harmless from and against any damages, judgments, claims,
suits, actions, liabilities, costs and expenses (including, but not

                                    Page 16
<PAGE>

limited to, reasonable attorneys' fees) resulting from any Third Party claims or
suits arising solely out of (a) Hollister-Stier's material breach of any of its
warranties or representations hereunder or (b) Hollister-Stier's grossly
negligent acts or omissions or willful misconduct in its performance of the CTM
Program or the manufacture or bulk packaging of the Product.

         7.3 Indemnification Procedures.

             (a) Any party hereto seaking indemnification hereunder (in this
context, the "indemnified party") shall notify the other party (in this context,
the "indemnifying party") in writing reasonably promptly after the assertion
against the indemnified party any Claim by a Third Party (a "Third-Party Claim")
in respect of which the indemnified party intends to base a Claim for
indemnification hereunder.

             (b) (i) The indemnifying party shall have the right, upon written
notice given to the indemnified party within 30 days after receipt of the notice
from the indemnified party of any Third Party Claim, to assume the defense and
handling of such Third Party Claim, at the indemnifying party's sole expense, in
which case the provisions of Section 7.3(b) (ii) below shall govern. (ii) The
indemnifying party shall select counsel reasonably acceptable to the indemnified
party in connection with conducting the defense and handling of such Third Party
Claim, and the indemnifying party shall defend or handle the same in
consultation with the indemnified party, and shall keep the indemnified party
timely appraised of the status of the Third Party Claim. The indemnifying party
shall not, without the prior written consent of the indemnified party, which
consent shall not be unreasonably withheld, agree to a settlement of any Third
Party Claim that could directly or indirectly lead to liability or create any
financial or other obligation on the part of the indemnified party for which the
indemnified party is not entitled to indemnification hereunder. The indemnified
party shall cooperate with the indemnifying party and shall be entitled to
participate in the defense or handling of such Third Party Claim with its own
counsel and at its own expense.

             (c) (i) If the indemnifying party does not give written notice to
the indemnified party, within 30 days after receipt of the notice from the
indemnified party of any Third Party Claim, of the indemnifying party's election
to assume the defense or handling of such Third Party Claim, the provisions of
Section 7.3(c)(ii) below shall govern. (ii) The indemnified party may, at the
indemnifying party's expense, select counsel in connection with conducting the
defense or handling of such Third Party Claim and defend or handle such Third
Party Claim in such manner as it may deem appropriate, provided, however, that
the indemnified party shall keep the indemnifying party timely appraised of the
status of such Third Party Claim and shall not settle such Third Party Claim
without prior written consent of the indemnifying party, which consent shall not
be unreasonably withheld. If the indemnified party defends or handles such Third
Party Claim, the indemnifying party shall cooperate with the indemnified party
and shall be entitled to participate in the defense or handling of such Third
Party Claim with its own counsel and at its own expense.

                                    Page 17
<PAGE>

             (d) If the indemnified party intends to seek indemnification
hereunder, other than for a Third Party Claim, then it shall notify the
indemnifying party in writing within three months after its discovery of facts
upon which it intends to base its Claim for indemnification hereunder; provided,
however, the failure to timely give such notice shall limit the indemnifying
party's liability for indemnification only to the extent the indemnifying
party's defense of such matter has been prejudiced.

             (e) Except with regard to fraud, the indemnification remedies in
this Article 7, enforced in accordance with Section 9.3, shall constitute the
sole and exclusive remedies of the parties with respect to any matters arising
under or relating to this CTM Agreement.

         7.4 Survival of Indemnification Obligations. The provisions of this
Article 7 shall survive the expiration or termination of this Agreement for a
period of five (5) years.

         7.5 Limitation of Liability and Claims. Hollister-Stier shall not be
liable to Client for indirect, incidental, special, punitive or consequential
damages of any kind, including without limitation lost profits or loss of good
will or otherwise. Neither Party's liability to the other under this Agreement
shall exceed five million dollars ($5,000,000).

         7.6 Insurance. Both Client and Hollister-Stier shall obtain and
maintain, either itself or through one or more of its affiliates, with reputable
carriers, product liability insurance with limits of not less than $10,000,000
per claim/annual aggregate by no later than the scheduled manufacturing date of
the first CTM batch. Each party hereto shall have its insurance carrier(s)
furnish the other party hereto with a certificate that such insurance is in
force. In the event of any proposed cancellation, non-renewal, or material
adverse change in such coverage, the other party hereto shall be given at least
thirty (30) days advance written notice thereof.

                                    ARTICLE 8

                              TERM AND TERMINATION

         8.1 Term. This Agreement shall remain in full force and effect to and
including June 30, 2005 unless and until terminated in accordance with the
provisions of this Article.

         8.2 Termination by Mutual Agreement. This Agreement may be terminated
at any time upon mutual written agreement between the Parties.

         8.3 Termination for Default. This Agreement may be terminated by either
Party in the event of the material breach or default by the other Party of the
terms and conditions hereof; provided, however, the other Party shall first give
to the defaulting Party written notice of the proposed termination or
cancellation of this Agreement, specifying the grounds therefor. Upon

                                    Page 18
<PAGE>

receipt of such notice, with respect to such defaults as are capable of being
cured, the defaulting Party shall have sixty (60) days to respond by curing such
default (or ten (10) days with respect to a failure by Client to pay any amounts
hereunder when due, with the exception of contested amounts for which Client has
provided notice to Hollister-Stier as provided in Section 2.4 hereof). If the
breaching Party does not so respond or fails so to work diligently and to cure
such breach within the additional time set forth above, then the other Party may
either suspend the Agreement indefinitely or terminate the Agreement.
Termination of this Agreement pursuant to this Section 8.3 shall not affect any
other rights or remedies which may be available to the nondefaulting Party.

         8.4 Bankruptcy; Insolvency. (i) Either Party may terminate this
Agreement upon the occurrence of any of the following with respect to the other
Party:

             (a) The entry of a decree or order for relief by a court having
jurisdiction in the premises in respect of such other Party in an involuntary
case under the Federal Bankruptcy Code, as now constituted or hereafter amended,
or any other applicable federal or state insolvency or other similar law and the
continuance of any such decree or order unstayed and in effect for a period of
sixty (60) consecutive days;

             (b) The filing by such other Party of a petition for relief under
the Federal Bankruptcy Code, as now constituted or hereafter amended, or any
other applicable federal or state insolvency or other similar law; or

             (c) The failure of such other Party to pay its debts when due.

             (ii) Hollister-Stier shall notify Client of its intent to file for
protection under the Federal Bankruptcy Code as soon as such a determination is
made. Hollister-Stier will segregate all Client-related documentation,
including, but not limited to, manufacturing and analytical equipment protocols,
qualifications, procedures, methods, calibrations reports and/or certificates,
Specifications, Manufacturing Batch Production Records, Intermediate and Product
analytical data, Hollister-Stier facility documentation in support of the CTM
Program; all Client provided manufacturing and analytical testing equipment,
including any equipment purchased by Client for Hollister-Stier in conjunction
with the CTM Program; all unconsumed raw materials provided by Client to
Hollister-Stier in conjunction with the CTM Program; and all Intermediate and
Product Batches, including stability samples, that were produced in accordance
with the CTM Program. Hollister-Stier will provide Client complete and total
access to these materials at Client's request.

         8.5 Termination without Cause. Client may terminate this CTM Agreement
without cause on ninety (90) days prior written notice to Hollister-Stier.

         8.6 Rights and Duties Upon Termination. Upon termination of this
Agreement Hollister-Stier shall, as promptly as practicable, (i) cease work on
the CTM Program, and (ii) turn over to Client all results, documentation and
information obtained during the CTM Program

                                    Page 19
<PAGE>

(whether in written or electronic form) which are then in Hollister-Stier's
possession and which are the property of Client in accordance with Article 2 of
this Agreement. Upon termination of this Agreement Client shall remain liable
for all fees, expenses and uncancellable obligations incurred hereunder through
the date of such termination, less any costs or expenses incurred by the
termination to move the CTM Program to another facility. If the Agreement is
terminated during the construction phase of the Facility renovations, Client
will be responsible for costs associated with completing the Facility
renovations (i.e., Capital equipment and facility renovations costs) in
accordance with Exhibit 9 of this Agreement. In addition, upon expiration or
termination of this Agreement, whichever is sooner, the Parties shall promptly
agree on a procedure which allows Client to possess any Equipment located at
Hollister-Stier's facility that is owned by Client (with Client paying all
reasonable costs to access and remove such equipment, including the cost of
removing special plumbing or electrical connections added in connection with the
original installation of such equipment). Upon termination, all ownership and
rights to inventions and technology shall be as set forth in Section 2.16
hereof. The provisions of Article 2, Section 2.2(i) and Article 4 hereof shall
survive any termination of this Agreement.

                                    ARTICLE 9

                        FORCE MAJEURE/DISPUTE RESOLUTION

         9.1 Effect of Force Majeure. Neither Party shall be held liable or
responsible for any loss or damages resulting from any failure or delay in its
performance due hereunder (other than the payment of money) caused by force
majeure. As used herein, force majeure shall be deemed to include any condition
beyond the reasonable control of the affected Party including, without
limitation, Acts of God, strikes or other labor disputes, war, riot, earthquake,
tornado, hurricane, fire, civil disorder, explosion, accident, flood, sabotage,
lack of or inability to obtain adequate fuel, power, materials, labor,
containers, transportation, supplies or equipment; compliance with governmental
requests, laws, rules, regulations, orders or actions; inability despite good
faith efforts to renew operating permits or licenses from local, state or
federal governmental authorities; breakage or failure of machinery or apparatus;
national defense requirements; or supplier strike, lockout or injunction.
Hollister-Stier shall notify Client of any foreseeable force majeure events,
including, but not limited to foreseeable strikes and other labor disputes,
shipping interruptions or problems, and inability to procure supplies necessary
for Hollister-Stier to perform any of its obligations under this CTM Agreement.

         9.2 Notice of Force Majeure. In the event either Party is delayed or
rendered unable to perform due to force majeure, the affected Party shall give
notice of the same and its expected duration to the other Party promptly after
the occurrence of the cause relied upon, and upon the giving of such notice the
obligations of the Party giving the notice will be suspended during the
continuance of the force majeure; provided, however, such Party shall take
commercially reasonable steps to remedy the force majeure with all reasonable
dispatch. The requirement that force majeure be remedied with all reasonable
dispatch shall not require the settlement of strikes

                                    Page 20
<PAGE>

or labor controversies by acceding to the demands of the opposing party.

         9.3 Dispute Resolution. The parties hereto hereby agree to perform the
terms of this CTM Agreement in good faith, and to attempt to resolve any
controversy, claim a dispute arising hereunder in good faith. Any dispute
regarding the validity, construction, interpretation or performance of this CTM
Agreement (other than any provisions, hereof relating to any intellectual
property, rights, or the confidentiality obligations contained in Article 4
hereof) shall be (i) first attempted to be resolved between the CEO/President of
each Party and failing that (ii) submitted to binding arbitration in Boston,
Massachusetts, U.S.A. to be conducted in accordance with the Arbitration Rules
of the American Arbitration Association ("AAA"); provided however, that nothing
in this Section 9.3 shall be construed to preclude either party from seeking
provisional remedies, including, but not limited to, temporary restraining
orders and preliminary injunctions, from any court of competent jurisdiction, in
order to protect its rights pending arbitration, but such preliminary relief
shall not be sought as a means of avoiding arbitration. Any arbitration
hereunder shall be submitted to an arbitration tribunal made up of three (3)
members, one of whom shall be selected by Client, one of whom shall be selected
by Hollister-Stier, and one of whom shall be selected by the other two
arbitrators. All arbitration proceedings shall be conducted in English. The
order or award of the arbitrators shall be final and may be enforced in any
court of competent jurisdiction. The prevailing party in any legal or
arbitration action brought by one party against the other shall be entitled, in
addition to any other rights and remedies it may have, to reimbursement for its
expenses incurred thereby, including court costs and reasonable attorneys' fees.
The parties shall have the right of limited prehearing discovery, including (i)
exchange of witness lists, (ii) exchange of documentary evidence and reasonably
related documents, (iii) written interrogatories, and (iv) subject to the
reasonable discretion of the arbitrators and upon good cause shown depositions
under oath of any witnesses who are to be called to testify at the arbitration
hearing. As soon as the discovery is concluded, the arbitrators shall hold a
hearing in accordance with the aforesaid shall hold a hearing in accordance with
the aforesaid AAA rules.

                                   ARTICLE 10

                                     NOTICES

         10.1 All notices provided for herein shall be in writing and shall be
deemed to be delivered when deposited in the United States mail, postage
prepaid, or hand-delivered to an authorized representative of the Party to whom
notice is directed, or sent by telex, facsimile, telegram or cable, charges
prepaid, to the address of the other Party designated below:

<TABLE>
<S>                                             <C>
         Client:                                Hollister-Stier:

         Acusphere, Inc.                        Hollister-Stier Laboratories LLC
         38 Sidney Street                       3525 North Regal Street
</TABLE>

                                    Page 21
<PAGE>

<TABLE>
<S>                                             <C>
         Cambridge, MA  02139                   Spokane, WA 99207
         Attention:  Thomas M. Hanlon III       Attention:  Anthony D. Bonanzino
         FAX:  617-577-0233                     FAX:  (509) 482-3543
</TABLE>

         The address and person provided above may be charged by either Party by
providing the other Party with written notice of such change.

                                   ARTICLE 11

                                  MISCELLANEOUS

         11.1 Entire Agreement. This Agreement and attachments contain the
entire understanding between the Parties with respect to the subject matter
hereof, and may be modified, only by a written instrument duly executed by each
Party's authorized representative.

         11.2 Independent Contractor. Client will not have the right to direct
or control the activities of Hollister-Stier performing the service provided
herein, and Hollister-Stier shall perform services hereunder only as an
independent contractor, and nothing herein shall be construed to be inconsistent
with relationship or status. Under no circumstances shall Hollister-Stier be
considered to be an employee or agent of Client, nor shall Client be liable in
any way for employment activities or employees of Hollister-Stier.

         11.3 Publicity. Any press release, publicity or other form of public
written disclosure related to this Agreement prepared by one Party shall be
submitted to the other Party prior to release for approval, which approval shall
not be unreasonably withheld or delayed by such other Party.

         11.4 Use of Party's Name. Except as expressly provided or contemplated
hereunder and except as otherwise required by applicable law, no right is
granted pursuant to this CTM Agreement to either Party to use in any manner the
trademarks or name of the other Party, or any other trade name, service mark, or
trademark owned by or licensed to the other Party in connection with the
performance of the CTM Agreement. Notwithstanding the above, the Parties shall
be permitted to use the other Party's name and marks in connection with general
advertising and promotional activities and, to the extent required by applicable
law, the parties shall be permitted to use the other Party's name and disclose
the existence and terms of this Agreement in connection with required public
regulatory filings, public securities filings and private placement memoranda
and documentation, using reasonable commercial efforts to protect the
confidentiality of the terms of this Agreement.

         11.5 Severability. Each Party hereby expressly agrees that it has no
intention to violate any public policy, statutory or common laws, rules,
regulations, treaty or decision of any government agency or executive body
thereof of any country or community or association of

                                    Page 22
<PAGE>

countries; that if any word, sentence, paragraph, clause or combination thereof
in this Agreement is found by a court or executive body with judicial powers
having jurisdiction over this Agreement or either Party hereto, in a final
unappealed order, to be in violation of any such provisions in any country or
community or association of countries, such words, sentences, paragraphs,
clauses or combination shall be inoperative in such country or community or
association of countries and the remainder of this CTM Agreement shall remain
binding upon the Parties, so long as enforcement of the remainder does not
violate the Parties' overall intentions in this transaction.

         11.6 Assignment; Subcontractors. This Agreement may not be assigned or
otherwise transferred by either Party without the prior written consent of the
other Party; provided, however, either Party may, without such consent, assign
this Agreement (a) in connection with the transfer or sale of all or
substantially all of the assets of such Party or the line of business of which
this Agreement forms a part, (b) in the event of the merger or consolidation of
a Party hereto with another company, or (c) to any Affiliate of the assigning
Party fully capable of performing hereunder. Any purported assignment in
violation of the preceding sentence shall be void. Any permitted assignee shall
assume all obligations of its assignor under this Agreement. No assignment shall
relieve either Party of responsibility for the performance of any obligation
which accrued prior to the effective date of such assignment.

         11.7 Governing Law. This Agreement shall be governed by and construed
in accordance with the laws of the state of Washington, irrespective of any
conflicts of law rule which may direct or refer such determination of applicable
law to any other state; and if this Agreement were performed wholly within the
state of Washington.

         11.8 Headings. Paragraph headings and captions used herein are for
convenience of reference only and shall not be used in the construction or
interpretation of this Agreement.

         11.9 Continuing Obligations. Termination, assignment or expiration of
this Agreement shall not relieve either Party from full performance of any
obligations incurred prior thereto.

         11.10 Waiver. Neither Party's waiver of any breach or failure to
enforce any of the terms and conditions of this CTM Agreement, at any time,
shall in any way affect, limit or waive such Party's right thereafter to enforce
and compel strict compliance with every term and condition of this CTM
Agreement.

         11.11 Construction. This Agreement has been jointly prepared on the
basis of the mutual understanding of the Parties and shall not be construed
against either Party by reason of such Party's being the drafter hereof or
thereof.

         11.12 Exhibits, Schedules and Attachments. Any and all exhibits,
schedules and attachments referred to herein form an integral part of this
Agreement and are incorporated into this Agreement by such reference.

                                    Page 23
<PAGE>

         11.13 Non-Competition. During the term of this Agreement and for two
(2) years thereafter, Hollister-Stier agrees that it shall not manufacture or
agree to manufacture any material using microsphere technology for use as or in
connection with an ultrasound contrast agent that competes with the Product.
Further, Hollister-Stier shall not use any inventions, processes, know-how,
trade secrets, improvements, other intellectual properties and other assets,
including but not limited to procedures and techniques, computer technical
expertise, software, and certain technical expertise and conceptual expertise
relating to the Intermediate and Product which have been independently developed
by Client or its Affiliates to assist any third party in connection with an
ultrasound contrast agent that competes with the Product.

         IN WITNESS WHEREOF, this Agreement has been executed by the Parties
hereto as of the day and year first written above.

ACUSPHERE, INC.                                 HOLLISTER-STIER LABORATORIES LLC

/s/ SHERRI C. OBERG                             /s/ A. BONANZINO
-------------------                             ----------------
Signature                                       Signature

Sherri. C. Oberg                                A. Bonanzino
----------------                                ------------
Name                                            Name

President and C.E.O.                            President and CEO
-------------------                             -----------------
Title                                           Title

                                    Page 24
<PAGE>

                                    Exhibit 1

                                (See Attachment)

                                    Page 25
<PAGE>

                                    EXHIBIT 1

         Hollister-Stier Laboratories LLC ("Hollister") and Acusphere, Inc.
("Client") have identified in this Exhibit 1 certain manufacturing activities to
be provided by Hollister-Stier, and various assumptions associated with the
project.

I.       MANUFACTURING ACTIVITIES

<TABLE>
<CAPTION>
         Category                   Description
         --------                   -----------

<S>                                 <C>
         Analytical                 Draft analytical testing method transfer for Client approval,
                                    execute analytical methods and equipment transfer, including
                                    confirmation of Client methods and procedures; draft analytical
                                    methods transfer report for Client approval; draft equipment
                                    transfer protocol for Client approval;  draft equipment procedure
                                    documents using Client supplied analytical method and
                                    equipment protocols and procedures for Client approval;
                                    conduct raw material release testing, conduct Intermediate and
                                    Product batch and stability testing; generate Intermediate and
                                    Product batch testing result reports for Client approval and
                                    release; draft release Specifications for raw material,
                                    Intermediate and Product testing using Client supplied raw
                                    material, Intermediate and Product Specifications for Client
                                    approval.

         Process Development        MSDS/Safety training; confirm Client's lyophilization cycle on
                                    Hollister-Stier's lyophilizer.

         Batch Precursor Work       Confirm performance of Client's vial, stopper and seal on
                                    Hollister-Stier production equipment; calibrate Client supplied
                                    equipment; execute I/OQ protocols of Client supplied equipment
                                    using Client supplied I/OQ protocols; draft equipment procedure
                                    documents using Client supplied protocols and procedures for
                                    Client approval; execute appropriate qualification or validation
                                    protocols on Hollister-Stier production equipment (i.e.,
                                    autoclave load patterns) for use with Client supplied equipment
                                    and components; draft Steam-in-place (SIP) protocols for Client
                                    supplied equipment for Client
</TABLE>

                                     1 of 8
<PAGE>

<TABLE>
<S>                                 <C>
                                    approval; execute Steam-in-place (SIP) protocols for Client
                                    supplied equipment; draft Steam-in-place (SIP) reports for
                                    Client approval, confirm Client supplied equipment cleaning
                                    procedures; execute minimum number of simulation,
                                    demonstration and development batches prior to aseptic
                                    validation batches; execute Process Simulation (Intermediate)
                                    and Media Fill (Product) batches (aseptic validation);
                                    create/update environmental monitoring procedures for
                                    Intermediate and Product manufacturing; confirm shipping
                                    container for bulk shipment of Product to Client designated
                                    location, using appropriate temperature monitoring device(s).

         Batch Activities           Draft Master Batch Production and Control records, including
                                    aseptic validation Batch Production and Control records, using
                                    Client supplied manufacturing and aseptic validation batch
                                    records for Client approval. (Labor associated with the
                                    manufacturing, inspection and packing of the (Intermediate) and
                                    Product is included in the batch cost).

         Post-Batch Activities      Preparation of CTM Program Summary Report following
                                    completion of contract, The content of the CTM Program
                                    Summary Report will be mutually agreed upon in writing by the
                                    Parties before execution.

         Stability Program          Draft Product stability testing protocol and stability report
                                    format for Client approval; store stability batches and conduct
                                    testing of all CTM/stability batches of the Product in upright
                                    and inverted orientations at accelerated and standard controlled
                                    storage conditions according to ICH guidelines and verified
                                    analytical methods; generate stability testing result reports to
                                    Client at appropriate frequency.
</TABLE>

         Hollister-Stier will submit invoices in accordance with Section 2.4 of
the CTM Agreement. The format of the invoice will be approved by the Client. The
invoice will be submitted to Client by no later than thirty (30) days from the
completion of an applicable milestone.

         The anticipated number of batches and batch costs are stated below. The
number of Development (Simulation) batches is an estimate. Hollister-Stier and

                                     2 of 8
<PAGE>

         Client shall cooperate in efforts to attempt to minimize the required
         number of these batches; and Hollister-Stier will invoice Client only
         for batches actually produced.

<TABLE>
<CAPTION>
Number       Batch Type     Batch Description/Purpose            Price/Batch (1)                    Total Price
------       ----------     -------------------------            ------------                       -----------
<S>          <C>            <C>                                  <C>                                <C>
1*           Water Batch    Test process recipes/activities      [CONFIDENTIAL TREATMENT            [CONFIDENTIAL TREATMENT
                                                                 REQUESTED] /*/                     REQUESTED] /*/
1-2*         Development    Simulation - [CONFIDENTIAL           [CONFIDENTIAL TREATMENT            [CONFIDENTIAL TREATMENT
                            TREATMENT REQUESTED] /*/             REQUESTED] /*/                     REQUESTED] /*/
3*           Media Fills    Validate batch processing            [CONFIDENTIAL TREATMENT            [CONFIDENTIAL TREATMENT
                                                                 REQUESTED] /*/                     REQUESTED] /*/
1***         CTM            Clinical trial/stability batches     [CONFIDENTIAL TREATMENT            [CONFIDENTIAL TREATMENT
                                                                 REQUESTED] /*/                     REQUESTED] /*/
2-6***       CTM            Clinical trial/stability batches     [CONFIDENTIAL TREATMENT            [CONFIDENTIAL TREATMENT
                                                                 REQUESTED] /*/                     REQUESTED] /*/
                                                                                                    ----------------------------

      Total Batch Cost                                                                              $2,950,000
</TABLE>

         * Includes costs for all raw materials and components.

         ** Includes costs for all raw materials and components, with the
         exception of the perfluorocarbon gas, phospholipid and polymer raw
         materials which will be supplied by Client.

         *** The CTM batch cost also includes inspection and bulk packaging.

         All Development (Simulation), Media Fill (including Process Simulation
         batches for the Intermediate) and CTM batches are comprised of one (1)
         Intermediate batch and one (1) Product batch.

         C.       Capital Costs.

                  Hollister-Stier anticipates that the following capital costs
         will be incurred in connection with this project. Renovations to the
         CTM Program Facilities are required to provide Client with CTM and
         commercial scale-up capability for manufacturing the Intermediate. The
         renovations will create a manufacturing area dedicated to Client.
         Excess capacity of this dedicated manufacturing area not utilized by
         Client may be used by Hollister-Stier upon written approval from
         Client. Such approval will not be unreasonably withheld. Client's
         manufacturing equipment may not be used by other Hollister-Stier
         clients.

<TABLE>
<CAPTION>
         Description                        Price
         -----------                        -----
<S>                                         <C>

         Facility Renovations               [CONFIDENTIAL TREATMENT REQUESTED] /*/
         Capital Equipment                  [CONFIDENTIAL TREATMENT REQUESTED] /*/

                  Total Capital Cost        NTE $1,251,150
</TABLE>

         Hollister-Stier will invoice Client for such capital costs in
         accordance with Section 2.4 of the CTM Agreement. Client will review
         and approve the layout and installation of its equipment within the CTM
         Program Facilities.

                                     3 of 8
<PAGE>

II.      TECHNOLOGY TRANSFER ACTIVITIES

         The parties have identified a series of technology transfer activities
required to prepare for Intermediate and Product batch production by
Hollister-Stier. The Technology Transfer Project activities listed in Section
II.A. of this Exhibit will be completed prior to the manufacture of CTM batches
of the Intermediate and Product.

         A.       Technology Transfer Project Activities.

                  The following activities, at a minimum, must be completed to
         enable Hollister-Stier to manufacture the Intermediate and the Product.
         The activities assume success at each stage; no contingency activities
         have been included as part of the project work or in estimates of
         price, modification of which will require mutual agreement of the
         parties.

         o Cleaning Methodology - verify the Intermediate and the Product can be
         removed from Hollister-Stier supplied manufacturing equipment and CTM
         Program Facilities, as applicable. Hollister-Stier will confirm that
         procedures are in-place to remove product residues other than the
         Intermediate and Product from Hollister-Stier supplied equipment and
         the CTM Program Facilities.
         o [CONFIDENTIAL TREATMENT REQUESTED] /*/
         o Biological Methods Development/Transfer - Sterility, LAL.
         o Qualification/Validation Activities - execute as set forth in Section
         I(A) Batch Precursor Work of this Exhibit.
         o Water Batch - One (1) full scale water batch/line test to verify
         the Intermediate and Product manufacturing processes: focal points
         include the Intermediate manufacturing process flow (includes
         homogenization), the Product manufacturing process, including fill
         accuracy, [CONFIDENTIAL TREATMENT REQUESTED] /*/, freeze drying,
         capping, loading and unloading. Hollister-Stier and Client acknowledge
         that water cannot simulate certain processing steps within the
         Intermediate and Product manufacturing processes.
         o Development (Simulation) Batches - One (1) to two (2) batches to
         simulate the Intermediate and Product manufacturing process using
         [CONFIDENTIAL TREATMENT REQUESTED] /*/ rather than active formulation
         and does not include the perfluorocarbon gas.
         o Process Simulation/Media Fills - a minimum of three (3) consecutive,
         successful Process Simulation/Media Fill batches to qualify the aseptic
         manufacturing of the Intermediate and the Product, and container
         closure integrity.
         o Clinical Trial Material Batches - Three (3) to six (6) batches
         using the active formulation and perfluorocarbon gas.

                                     4 of 8
<PAGE>

         o Hollister-Stier agrees to work with Client to attempt to minimize the
         number of Development batches required and will bill only for batches
         actually performed.

         B.   Assumptions.

         Manufacturing Assumptions

         1.         Project may require completion of MSDS, Safety Assessment,
                  Environmental Assessment, and Waste Disposal procedures as
                  appropriate for this project. Costs associated with these
                  assessments will be borne by Hollister-Stier. The parties
                  shall in good faith identify capital expenditures needed to
                  achieve compliance with safety and environmental issues and to
                  the relative responsibility of each party to pay for any such
                  expenditures.

         2.         Hollister-Stier will furnish all raw materials and
                  components for all activities, with the exception of the
                  polymer, phospholipid and perfluorocarbon gas which will be
                  provided by Client. Sampling and release testing [CONFIDENTIAL
                  TREATMENT REQUESTED] /*/ will be performed at Hollister-Stier
                  on all raw materials and components supplied by
                  Hollister-Stier and including all raw materials supplied by
                  Client; additional release testing will be performed by an
                  outside laboratory as stated in Item #23 of the Analytical
                  Assumptions Section.

         3.         Client will be responsible for [CONFIDENTIAL TREATMENT
                  REQUESTED] /*/ disposal costs. Hollister-Stier to identify
                  appropriate disposal company and disposal cost/55 gallon drum.

         4.         Development of procedures for recovery of unused
                  perfluorocarbon gas is not included in this proposal.

         5.         Client will (in good faith) approve master batch
                  documentation using Hollister-Stier's documentation approval
                  procedures prior to change implementation. The Master Batch
                  Documentation includes: Master Formulas (a.k.a. Manufacturing
                  Work Orders), Filling Work Orders (Fwos), equivalent documents
                  for Process Simulation/Media Fill Batches, Bills of Materials
                  for Filling & Packaging Operations and SOPs for dedicated
                  Client supplied equipment. Client will approve all protocols
                  for proposed Validation work for the Client's Intermediate and
                  Product specific equipment, processes and systems. Client
                  reserves the right to approve additional documents as they are
                  defined.

         6.         All cleaning procedures will be verified by Hollister-Stier.
                  Hollister-Stier will develop suitable residue methods, if
                  required. Hollister-Stier will verify that the Intermediate
                  and the Product can be removed from Hollister-Stier supplied
                  manufacturing equipment and CTM Program

                                     5 of 8
<PAGE>

                  Facilities, as applicable. Hollister-Stier will confirm that
                  procedures are in-place to remove product residuals other than
                  the Intermediate and Product from Hollister-Stier supplied
                  equipment and the CTM Program Facilities.

         7.         The batch size is estimated at [CONFIDENTIAL TREATMENT
                  REQUESTED] /*/ of the Intermediate, and [CONFIDENTIAL
                  TREATMENT REQUESTED] /*/ of the Product , with an estimated
                  yield of [CONFIDENTIAL TREATMENT REQUESTED] /*/ vials of
                  Product .

         8.         Primary packaging consists of

                  Schott-West 20-mL type 1 tubing vials - West Catalog No.:
                  68000321 Daikyo 20mm Flurotech stoppers - West Catalog No.:
                  V10-F451W SVLYO West 20mm flip-off seals - West Catalog No.:
                  5420-2054

         9.         [CONFIDENTIAL TREATMENT REQUESTED] /*/

         10.        [CONFIDENTIAL TREATMENT REQUESTED] /*/

         11.        Metrology schedules for manufacturing equipment will be
                  jointly agreed upon by Client and Hollister-Stier.

         12.        Manufacturing facility temperature and humidity requirements
                  for the Intermediate and Product are as follows: temperature
                  (less than or equal to) 23(Degree)C; humidity (less than or
                  equal to) 55% RH.

         13.        The Product will be 100% manually inspected following
                  capping. Hollister-Stier and Client will jointly determine
                  inspection criteria for acceptability.

         14.        A minimum of three (3) consecutive, successful Process
                  Simulation/Media Fill batches is required for the aseptic
                  processing qualification and container/closure integrity
                  testing. The cost of additional Process Simulation/Media Fill
                  batches is outside of the scope of this proposal.

         15.      CTM batches will be bulk packaged unlabeled.

         Analytical Assumptions

         16.        The project requires Analytical Methods Transfer and assay
                  verification for pertinent analytical testing. Client will
                  approve the Analytical Standards (Raw Materials and
                  Intermediate and Product Specifications, Test Methods and
                  Addenda) prior to change implementation. Client will receive
                  and approve all Master Analytical Method Transfer Protocols
                  and Reports, all Master Analytical Standards Documents (Raw
                  Materials,

                                     6 of 8
<PAGE>

                  Intermediate and Product Specifications, Testing and Agenda
                  and Standard Operating Procedures (SOPs)) for Client supplied
                  equipment. Client reserves the right to approve additional
                  documents as they are defined.

         17.        Hollister-Stier will perform release testing of liquid
                  nitrogen used in the manufacturing processes for the
                  Intermediate and Product.

         18.        Transfer of the Intermediate and Product ID, in-process and
                  release methods, and transfer of the Sterility, and LAL
                  methods, will consist of closely adapting Client's validated
                  methods and confirming their validity.

         19.        Analytical methods and specifications must be generated by
                  Hollister-Stier and approved by Client for raw materials, the
                  Intermediate and Product. Analytical methods and
                  specifications are critical documents and review and approval
                  is required per assumption #16.

         20.        The project assumes that the scope of analytical testing at
                  Hollister-Stier includes: [CONFIDENTIAL TREATMENT REQUESTED]
                  /*/. These tests will be performed as in-process or release
                  tests once finalized by Client. Closure integrity testing will
                  be required for stability.

         21.        In order for Hollister-Stier to perform certain release
                  testing for the Product, it may be necessary to purchase
                  additional capital equipment for the laboratory.
                  Hollister-Stier will notify Client prior to the purchase of
                  additional equipment, if required. Client will provide this
                  additional equipment to Hollister-Stier, as appropriate.

         22.        Stability sample controlled storage and testing of the
                  Product will be performed by Hollister-Stier.

         23.        (1)HNMR testing will be performed by a contract laboratory.

         24.        The first three (3) QA released CTM batches will be placed
                  on stability.

                                     7 of 8
<PAGE>

         General Assumptions

         25.        Client will compensate Hollister-Stier for travel and other
                  expenses associated with a technical transfer discussion at
                  the current site of manufacture, if required.

         26.        Hollister-Stier Regulatory Affairs will provide, at a
                  minimum, in-house regulatory support, necessary documentation
                  to support regulatory submissions, including raw data, and
                  regulatory consulting activities. Regulatory consulting will
                  be billed on a per-hour basis [CONFIDENTIAL TREATMENT
                  REQUESTED] /*/.

         27.        Following successful completion of the required Process
                  Simulation/Media fill batches, Hollister-Stier will be
                  responsible for manufacturing the Intermediate and Product to
                  agreed specifications.

         28.        The project assumes that Hollister-Stier does not have to
                  purchase new equipment for the manufacture of the Intermediate
                  and Product. Purchases not agreed by the parties are outside
                  the scope of the project.

         29.        Shipping of Product will be at Client's expense, with
                  delivery FOB Spokane, WA.

         30.        The Intermediate and Product will be manufactured according
                  to USP, EP, and applicable cGMP requirements.

         31.        Client personnel will be available on site to serve on the
                  Project Team. Hollister-Stier will provide an appropriate
                  office space for Client personnel (2 individuals) as set forth
                  in Section 2.14 of the CTM Agreement.

         32.        Client will conduct a formal cGMP audit of the appropriate
                  manufacturing and analytical areas associated with this
                  project. The audit date will be mutually agreed upon by both
                  parties, but must occur before August 31, 2001. Prior to
                  initiating the CTM Program, Hollister-Stier will promptly
                  remedy to Client's satisfaction any reasonable issues or
                  concerns noted during Client's formal cGMP audit.

                                     8 of 8
<PAGE>

                                    Exhibit 2

                     Intermediate and Product Specifications

                                    Page 26
<PAGE>

                                    Exhibit 3

                                    Schedule

                     [CONFIDENTIAL TREATMENT REQUESTED] /*/

                                    Page 27
<PAGE>

                                    Exhibit 4

                                  Documentation

Analytical Documentation

         1.   Method Transfer Protocols
         2.   Method Transfer Final Report
         3.   Equipment SOP's (for Acusphere provided equipment)

Raw Material/Manufacturing Component/Product Documentation

         1.   Raw Material and Manufacturing Component Specification Sheets
         2.   PLGA Microspheres for AI-700 Specification
         3.   AI-700 Specification
         4.   Raw Material and Manufacturing Component Release Reports
         5.   PLGA Microspheres for AI-700 Certificate of Analysis
         6.   PLGA Microspheres for AI-700 Certificate of Compliance
         7.   AI-700 Certificate of Analysis
         8.   AI-700 Certificate of Compliance
         9.   Bulk Shipping Label Format

Manufacturing Documentation

         1.   Equipment I/OQ Protocols (for Acusphere provided equipment)
         2.   Equipment SIP Protocols (for Acusphere provided equipment)
         3.   Equipment SOP's (for Acusphere provided equipment)
         4.   Qualification or Validation protocols on Hollister-Stier equipment
              used in conjunction with Acusphere equipment or
              processes (e.g., autoclave - load patterns)
         5.   Aseptic manufacturing batch records (Process Simulation & Media
              Fills)
         6.   PLGA Microspheres for AI-700 manufacturing batch records
         7.   AI-700 manufacturing batch records
         8.   Equipment Cleaning & Use Log Books for all manufacturing equipment
              (Acusphere or Hollister-Stier) used in this project
         9.   Certificates of Calibration for Acusphere-supplied equipment
         10.  Preventative maintenance or maintenance work orders preformed on
              Acusphere-supplied equipment
         11.  Environmental Monitoring Data/batch
         12.  WFI Data/batch
         13.  Deviations/Incidents
         14.  Investigations
         15.  Change Control documents
         16.  Bulk Package/Shipping Records

Stability Documentation

         1.   Stability Protocol
         2.   Stability Reports

                                    Page 28
<PAGE>

                                    Exhibit 5

                     Analytical and Manufacturing Equipment

                     [CONFIDENTIAL TREATMENT REQUESTED] /*/

                                    Page 29
<PAGE>

                               Exhibit 5 (cont'd)

                     Analytical and Manufacturing Equipment

                     [CONFIDENTIAL TREATMENT REQUESTED] /*/

                                    Page 30
<PAGE>

                                    Exhibit 6

      Intermediate and Product Master Batch Production and Control Records

                                    Page 31
<PAGE>

                                    Exhibit 7

 Intermediate and Product Master Quality Control Analytical Testing Methods
                                 and Procedures

                                    Page 32
<PAGE>

                                    Exhibit 8

                  Analytical Testing Method Transfer Protocols

                                    Page 33
<PAGE>

                                    Exhibit 9

                         H-S CTM Manufacturing Proposal

                                (See Attachment)

                                    Page 34
<PAGE>

August 16, 2001

Mr. Thomas M. Hanlon III
Senior Director, Manufacturing and Process Development
Acusphere, Inc.
University Park at M.I.T.
38 Sidney Street
Cambridge, MA  02139

Dear Mr. Hanlon:

Hollister-Stier Laboratories LLC (H-S) is pleased to provide the following
quotation for the aseptic manufacturing of PLGA Microspheres and AI-700 for
clinical trials. The scope of this quote includes production of CTM batches and
the stability program associated with those batches. Commercial production of
the product is not included in this proposal.

Project Assumptions
1.       Manufacturing Assumptions

         1.1      Projected AI-700 Lot Size: [CONFIDENTIAL TREATMENT REQUESTED]
                  /*/ vials maximum (approximately [CONFIDENTIAL TREATMENT
                  REQUESTED] /*/).

         1.2      One (1) batch of PLGA Microspheres will produce one (1) batch
                  of AI-700.

         1.3      All manufacturing process equipment to be provided by
                  Acusphere.

         1.4      Hollister-Stier will purchase the following excipient
                  ingredients as specified by Acusphere: [CONFIDENTIAL TREATMENT
                  REQUESTED] /*/. All of the raw materials listed above can be
                  stored at room temperature.

         1.5      The following raw materials will be provided by Acusphere for
                  all development and CTM batches: Polymer (2-8(Degree)C
                  storage), Phospholipid (less than -20(Degree)C storage), and
                  Perfluorocarbon Gas (room temperature storage). Acusphere will
                  be responsible for the cost and coordination of the shipment
                  for these bulk raw materials.

         1.6      Acusphere will provide the Lyophilization cycle.

<PAGE>

         1.7      Acusphere will provide insulated packaging for the shipment of
                  finished product. Temperature monitoring methods and
                  instrumentation used during shipment will be provided by
                  Acusphere. Acusphere will provide any hardware and software
                  required to run, download, or program their devices.

         1.8      Product will be shipped F.O.B. Spokane to a single location
                  designated by Acusphere at Acusphere's expense and liability.

         1.9      Finished product will be stored at H-S between 2-8(Degree)C.

         1.10     The cost of the [CONFIDENTIAL TREATMENT REQUESTED] /*/ are
                  included in the batch production cost.

         1.11     The minimum shelf temperature that can be reliably attained on
                  the Edwards Lyophilizer is -45(Degree)C.

         1.12     At this time H-S is assuming that employee health screening
                  will not be required for the use of [CONFIDENTIAL TREATMENT
                  REQUESTED]/*/. Acusphere has provided H-S with a health
                  screening history of their employees.

         1.13     [CONFIDENTIAL TREATMENT REQUESTED] /*/

         1.14     Process equipment operation and trouble shooting will be the
                  responsibility of Acusphere. This responsibility will be
                  transferred to H-S upon the first CTM batch.

2.       Documentation Assumptions

         2.1      Revisions to SOPs related to the operation of the process
                  equipment and batch records will be the responsibility of H-S.
                  [CONFIDENTIAL TREATMENT REQUESTED] /*/

         2.2      The SOP for the integrity testing of solution filters will be
                  the responsibility of H-S.

         2.3      H-S will perform equipment I/OQs that will be provided
                  electronically by Acusphere. A very brief protocol supplement
                  will be written by H-S to document the performance of
                  Acusphere's I/OQ and any additional qualification steps
                  required. The supplement will be issued an H-S protocol number
                  and will follow the H-S standard protocol filing procedure.
                  Both H-S and Acusphere will approve the protocol supplements.

                                     Page 2
<PAGE>

3.       QA Assumptions

3.1      Acusphere's approval to proceed with this project is contingent on the
         successful completion of a cGMP audit. This cGMP audit is currently
         being scheduled for the week of August 20th, 2001.

3.2      Product will be produced using Hollister-Stier's general quality
         control program, subject only to product specific changes.

3.3      Acusphere will provide copies of all relevant test procedures, method
         validation reports, and product and component specifications. These
         will be converted to H-S format. Both H-S and Acusphere will approve
         procedures and method validation reports. Acusphere will support the
         technical transfer of test procedures and method validation.

3.4      Acusphere will provide the polymer, phospholipid, and perfluorocarbon
         needed to produce the required product. [CONFIDENTIAL TREATMENT
         REQUESTED] /*/

3.5      Acusphere will provide:

         3.5.1    [CONFIDENTIAL TREATMENT REQUESTED] /*/

         3.5.2    [CONFIDENTIAL TREATMENT REQUESTED] /*/

         3.5.3    [CONFIDENTIAL TREATMENT REQUESTED] /*/

3.6      Validated/qualified methods will be provided by Acusphere for all
         analytical testing.

3.7      Retention sample storage will be an H-S responsibility and will satisfy
         the requirements of Acusphere. Retention sample storage environmental
         conditions will be 2-8(Degree)C.

3.8      Regulatory support is currently undefined.

3.9      Stability sample incubation and the stability test program will be the
         responsibility of H-S. Stability test quantities and environmental
         conditions are listed on page 10 of this proposal.

3.10     H-S will perform endotoxin and sterility testing in-house using
         qualified/validated methods transferred from Acusphere contract
         laboratories.

3.11     An outside laboratory will perform container/closure integrity testing
         by dye leakage. H-S will be responsible for shipment of vials to the
         laboratory.

                                     Page 3
<PAGE>

4.       Validation Assumptions

4.1      Solution filter validation will be completed by Acusphere by Q4, 2001.

4.2      [CONFIDENTIAL TREATMENT REQUESTED] /*/

4.3      [CONFIDENTIAL TREATMENT REQUESTED] /*/

4.4      [CONFIDENTIAL TREATMENT REQUESTED] /*/

5.       Engineering/Facility Assumptions

         5.1      In the new production facility design, H-S will provide floor
                  space encompassing existing rooms S17, S19, S18A, and portions
                  of S12 and S8 in the area formerly known as Allpyral. In
                  addition, H-S will provide a temporary equipment qualification
                  area known as S28.

         5.2      Travel to meet the requirements of this project will be billed
                  to Acusphere at cost. H-S has identified two pieces of
                  critical equipment that will require Factory Acceptance
                  Testing (F.A.T.) and/or design review visits. These pieces of
                  equipment are the aseptic compounding booth and the facility
                  Air-Handling Unit (AHU). Travel and expenses will be invoiced
                  separately (at cost) and no labor will be charged. Any vendor
                  visits will be discussed with the Acusphere Project Manager
                  prior to travel, and a visit report/copies of receipts will be
                  issued to Acusphere with the invoice. Acusphere may wish to
                  attend these F.A.T. or design review visits, and this is
                  acceptable to H-S. The total cost of project travel will not
                  exceed $20,000.

         5.3      Disposal of the used [CONFIDENTIAL TREATMENT REQUESTED] /*/ is
                  included in the batch production cost.

         5.4      H-S will provide cleaning and use logs for the process
                  equipment.

         5.5      Factory calibrations required on sophisticated instrumentation
                  will be provided by Acusphere. All other instrument
                  calibrations will be provided by H-S.

         5.6      Process hoses, filters, filter stands, support equipment, and
                  equipment spare parts will be provided by Acusphere.

                                     Page 4
<PAGE>

         5.7      A floor scale for compounding accountability will be provided
                  by Acusphere. The floor scale will be provided with an
                  appropriate printer in order to document the critical steps
                  during the processing.

         5.8      The facility renovation project schedule holds a 3-week
                  contingency. Delivery time lines from vendors have not been
                  received for the following: critical equipment, A&E firms,
                  construction firms or demolition crews. These lead times could
                  have an impact on the estimated completion date.

ATTACHMENTS TO QUOTE

1.       CTM Project Schedule
         A preliminary project schedule is provided in Section #1. The scope of
         this schedule includes the manufacture of the first batch of CTM
         material. All other CTM batches will proceed per a schedule supplied by
         Acusphere and agreed upon by H-S.

2.       CTM Facility Renovation Layout
         A preliminary facility renovation layout is provided in Section #2.
         This preliminary design was the result of a joint effort between the
         Acusphere and H-S Engineering groups. The scope of this design is to
         provide PLGA Microsphere CTM and commercial scale up capacity for
         Acusphere. Facility capacity not used by Acusphere can be used by H-S
         for the production of other CTMs. Acusphere will have pre-notification
         of the other product types to be manufactured in the CTM facility.

3.       CTM Facility Renovation Schedule
         A preliminary facility renovation schedule is provided in Section #3.
         This renovation schedule is based on H-S experience, and no timelines
         have been provided by contractors.

4.       CTM Facility Renovation Costs/Equipment Costs
         A preliminary facility renovation cost spreadsheet is provided in
         Section #4. This renovation schedule is based on H-S experience, and no
         formal quotes have been provided by contractors or vendors. Acusphere
         will retain ownership of all portable equipment.

5.       CTM Facility Documentation Costs
         A variety of costs related to validation and documentation are
         referenced in Section #5. All prices are estimates, subject to change
         as the project is more clearly defined.

6.       Product Release Testing and Stability Program Testing
         A spreadsheet is attached in Section #6 which delineates all analytical
         testing required for product release and for the stability program.

                                     Page 5
<PAGE>

7.       Detailed Costs for the Stability Study Program.
         A document is reflected in Section #7, which delineates details on the
         costs associated with the stability study program.

8.       Copies of Presentation
         Section #8 includes copies of the PowerPoint Presentation provided in
         Cambridge, MA on August 7, 2001.

PROJECT COSTS

1.       One Time Technology Transfer Costs

         1.1      Various costs related to validation and documentation. These
                  costs are detailed in Section #5. [CONFIDENTIAL TREATMENT
                  REQUESTED] /*/

         1.2      Project Management

            Project Leader: 6 months [CONFIDENTIAL TREATMENT REQUESTED] /*/
            -  Primary project interface at H-S, track the project schedule,
               organize and chair the team meetings, budget tracking, meeting
               minutes, project book management, control of project scope.

            Facility Engineer: 6 months [CONFIDENTIAL TREATMENT REQUESTED] /*/
            -  Primary responsibility for facility design, utility design,
               demolition, renovation, equipment purchase, contractor
               supervision, documentation, commissioning, qualification, etc.

            Equipment Engineer: 6 months [CONFIDENTIAL TREATMENT REQUESTED] /*/
           -   Specification and purchase of the aseptic compounding booth, the
               chemical fume hood, the -20(Degree)C freezer, components for SIP
               of the control piping and drying coil of the spray dryer and five
               (5) tanks, permit management, electrical installation and
               supervision, set up of process development area, Building
               Automation System, drawing support, etc.

            Analytical Scientist: 6 months total [CONFIDENTIAL TREATMENT
               REQUESTED] /*/
            -  Familiarization/Preparation for Tech Transfer: 3 months
               - Review analytical package.
               - Ensure H-S equipment/reagents/supplies are available and
                 in-place.
               - Set-up, training with [CONFIDENTIAL TREATMENT REQUESTED] /*/
                 representative.
               - Training time with Acusphere analyst.
               - Establish assay parameters with "training" supplies.
            -  Tech Transfer: 3 months
               - Provide written draft of protocol with Acusphere procedures and
                 input for acceptance criteria, to encompass all analytical
                 methodologies to be transferred, edited, with final approval by
                 both sites.
               - Complete the studies upon approval of the protocol.

                                     Page 6
<PAGE>

               - Investigation of unexpected results and resolution of any
                 problems.
               - Provide final acceptance report for approval at both sites.
               - Convert procedures to H-S format and receive approval from H-S
                 and Acusphere.
               - Unplanned analytical support for process work.

            Validation Support - Sterilization Process: 3 months[CONFIDENTIAL
            TREATMENT REQUESTED] /*/

            -  Develop and validate the autoclave sterilization loads for all
               aseptic assembly parts and all SIP validation support. This
               includes full validation on [CONFIDENTIAL TREATMENT REQUESTED]
               /*/ processing tanks and the spray dryer skid.

            Production: 6 months [CONFIDENTIAL TREATMENT REQUESTED] /*/
            -  Development of 4 batch records to include PLGA Microspheres,
               AI-700, Process Simulation [CONFIDENTIAL TREATMENT REQUESTED] /*/
               and media fill batch records, manufacturing and PIC coordination,
               SOP writing, development of filling/freezing process, and
               lyophilizer cycle development and test runs.

            Dedicated Process Specialist: 6 months[CONFIDENTIAL TREATMENT
            REQUESTED] /*/
            -  This will include one validation person who will be responsible
               for performance of equipment I/OQ, writing/modifying SOPs,
               learning the process and operation of the equipment,
               commissioning of equipment, and I/OQ supplements.

            Regulatory Support: 1 month TBD
            -  FDA notification for major utility modifications, CBE30 for SLM
               area. These activities are not yet defined and will be billed for
               actual hours worked @[CONFIDENTIAL TREATMENT REQUESTED] /*/.

            TOTAL: PROJECT MANAGEMENT ONE TIME COST
            [CONFIDENTIAL TREATMENT REQUESTED] /*/

            NOTE: If this project extends for greater than 6 months (up to the
            point of the first development batch) additional time will be
            charged at the standard [CONFIDENTIAL TREATMENT REQUESTED] /*/.

         1.3      New Capital Equipment Costs - (see details in Section #4)
                  [CONFIDENTIAL TREATMENT REQUESTED] /*/

         1.4      Facility Renovation Costs - (see details in Section #4)
                  [CONFIDENTIAL TREATMENT REQUESTED] /*/

                                     Page 7
<PAGE>

         1.5      Process Development and Commissioning Area. In order to
                  expedite the project schedule, H-S is recommending immediate
                  receipt of the process equipment for development work. A
                  dedicated commissioning area for the receipt and testing of
                  this equipment has been identified. The area is rich in
                  utilities such as electrical, compressed air and nitrogen in
                  order to start up and commission equipment. Modifications will
                  be required to the existing electrical in this area, and a
                  short clean steam run will need to be installed. Relocation of
                  the existing racking, equipment and spare parts located in the
                  area will be required. SIP development for the processing
                  vessels will be of prime importance in this area.
                  [CONFIDENTIAL TREATMENT REQUESTED] /*/

         TOTAL ONE TIME COST FOR ANALYTICAL METHODS TRANSFER, VALIDATION, SOPS,
         FOUR BATCH RECORDS, MISCELLANEOUS DOCUMENTATION, PROJECT MANPOWER, NEW
         CAPITAL EQUIPMENT, FACILITY RENOVATION, AND THE RENOVATION OF ROOM S28
         =[CONFIDENTIAL TREATMENT REQUESTED] /*/

2.       PAYMENT SECTION
         PAYMENT SCHEDULE FOR TECHNOLOGY TRANSFER ONE TIME COSTS

         2.1      Payment #1, [CONFIDENTIAL TREATMENT REQUESTED] /*/ for down
                  payment on long lead-time equipment and the initiation of
                  contracted design for the facility renovation. Long lead-time
                  equipment includes AHU, aseptic compounding booth, heat
                  exchangers, HEPA filters and housings, S.S. doors and frames,
                  etc. Receipt of [CONFIDENTIAL TREATMENT REQUESTED] /*/ and
                  approval of the quotation will initiate the project and the
                  purchase of long lead-time equipment.

         2.2      Payment #2, [CONFIDENTIAL TREATMENT REQUESTED] /*/ of the
                  total one time technology transfer cost [CONFIDENTIAL
                  TREATMENT REQUESTED] /*/ to be paid approximately 30 days from
                  the initiation of the project. It is the goal of H-S and
                  Acusphere to have a signed contract by payment #2.

         2.3      Payment #3, [CONFIDENTIAL TREATMENT REQUESTED] /*/ of the
                  total one time technology transfer cost [CONFIDENTIAL
                  TREATMENT REQUESTED] /*/ to be paid upon achieving the
                  facility renovation project schedule midpoint (milestone
                  payment is referenced on project schedule). Two credits will
                  be provided on this payment.

                  2.3.1    The down payment of [CONFIDENTIAL TREATMENT
                           REQUESTED] /*/ will be credited on this payment.

                  2.3.2    At this early stage in the facility renovation
                           design, H-S Engineering is confident of a NTE
                           facility renovation cost including a [CONFIDENTIAL
                           TREATMENT REQUESTED] /*/ contingency. Upon completing
                           the A&E design, H-S Engineering will have developed a
                           facility renovation cost plus a [CONFIDENTIAL
                           TREATMENT REQUESTED] /*/ contingency. The
                           [CONFIDENTIAL TREATMENT REQUESTED] /*/ contingency
                           amount is scheduled to be available by 10-6-01. The
                           cost of the facility renovation with a [CONFIDENTIAL
                           TREATMENT REQUESTED] /*/ contingency is expected to
                           be less than the current facility

                                     Page 8
<PAGE>

                           renovation estimate detailed on this proposal. If the
                           [CONFIDENTIAL TREATMENT REQUESTED] /*/ contingency
                           cost is less than the current estimate, the
                           difference will be credited to Acusphere.

         2.4      Payment #4, [CONFIDENTIAL TREATMENT REQUESTED] /*/ of the
                  total one time technology transfer cost [CONFIDENTIAL
                  TREATMENT REQUESTED] /*/ to be paid upon performance of the
                  first development batch.

3.       Qualification Run Charges

         3.1      Development Batch (1)   [CONFIDENTIAL TREATMENT REQUESTED] /*/

         3.2      Process Simulation/Media Fill [CONFIDENTIAL TREATMENT
                  REQUESTED] /*/
                                          [CONFIDENTIAL TREATMENT REQUESTED] /*/

         3.3      Qualification run billing schedule: Upon producing the
                  development batch, an invoice will be submitted to Acusphere
                  with NET 30 payment terms. Upon completing the 14-day
                  incubation period for media fills and performing the media
                  inspection, an invoice will be submitted to Acusphere with NET
                  30 payment terms.

4.       Routine Production Costs - Routine production costs are based on H-S
         providing the following services:

         4.1      Purchasing and releasing of excipient raw materials and
                  components including vials, stoppers, and seals as specified
                  by Acusphere.

         4.2      Aseptic processing of PLGA Microspheres and aseptic processing
                  of AI-700.

         4.3      Individual product vials will not be labeled or ink jetted.
                  The finished product vials will be placed into Acusphere's
                  insulated package and bulk labeled by H-S. H-S will not
                  provide any packaging design support. Acusphere will supply
                  H-S a letter requesting the vials to be shipped without labels
                  or ink jetting.

         4.4      Cosmetic inspection for vial defects, missing stoppers,
                  stopper defects, seal defects, cake cosmetics and color, and
                  gross particulate.

         4.5      Required product release testing (see Section #6 for specific
                  testing to be performed) and retention sample storage.

         4.6      AI-700 batch size will be limited to the maximum capacity of
                  the Edwards Lyophilizer, which is [CONFIDENTIAL TREATMENT
                  REQUESTED] /*/ vials.

         4.7      H-S will provide copies to Acusphere of requested
                  manufacturing, analytical and environmental documentation
                  associated with each CTM batch produced.

                                     Page 9
<PAGE>

         4.8      Price per batch of CTM material produced. The current estimate
                  is [CONFIDENTIAL TREATMENT REQUESTED] /*/ in Q1/Q2 of 2002.
                  [CONFIDENTIAL TREATMENT REQUESTED] /*/

                  NOTE: Upon completing batch record documentation for each CTM
                  batch, an invoice will be submitted to Acusphere with NET 30
                  payment terms.

5.       Stability Program Costs (detailed breakdown of costs are provided in
         Section #7).

         5.1      [CONFIDENTIAL TREATMENT REQUESTED] /*/

         5.2      [CONFIDENTIAL TREATMENT REQUESTED] /*/

         5.3      Container/closure Integrity test at [CONFIDENTIAL TREATMENT
                  REQUESTED] /*/ time points: [CONFIDENTIAL TREATMENT REQUESTED]
                  /*/ upright vials and [CONFIDENTIAL TREATMENT REQUESTED] /*/
                  inverted vials. [CONFIDENTIAL TREATMENT REQUESTED] /*/ vials
                  from each CTM batch will be tested for closure integrity.
                  Closure integrity testing will be performed at an outside
                  laboratory, and H-S will be responsible for the shipment and
                  documentation of the results of the testing.

                  Total stability program cost/lot is [CONFIDENTIAL TREATMENT
                  REQUESTED] /*/ =[CONFIDENTIAL TREATMENT REQUESTED] /*/

<TABLE>
<CAPTION>
PROJECT COST SUMMARY
<S>                                                                       <C>

One Time Technology Transfer Costs......................................  [CONFIDENTIAL TREATMENT REQUESTED] /*/
One Development Batch ..................................................  [CONFIDENTIAL TREATMENT REQUESTED] /*/
Process Simulation/Media Fill [CONFIDENTIAL TREATMENT REQUESTED] /*/ ...  [CONFIDENTIAL TREATMENT REQUESTED] /*/
CTM Batches [CONFIDENTIAL TREATMENT REQUESTED] /*/ .....................  [CONFIDENTIAL TREATMENT REQUESTED] /*/
Stability Program Costs.................................................  [CONFIDENTIAL TREATMENT REQUESTED] /*/

TOTAL PROJECT COST                                                        $4,340,300 - $5,232,900

</TABLE>

REGULATORY STATUS
CBER (Team Biologics) inspected Hollister-Stier in September of 2000. This
inspection was a general inspection of the entire facility including SVP. The
FDA Form 483 issued at the conclusion of the inspection contained 13
observations, all of which were addressed by January 2000. CBER categorized the
inspection as Voluntary Action Indicated (VAI). Hollister-Stier also received a
PAI and Establishment Inspection by CDER in September 1999. This inspection
resulted in approval of the SVP Department, and no FDA Form 483 was issued.

                                    Page 10
<PAGE>

Hollister-Stier is very excited about the opportunity to work with Acusphere on
the PLGA and AI-700 project, and we are confident of our ability to meet your
requirements. Since Acusphere's project timeline is critical, we suggest that
Hollister-Stier and Acusphere sign a Letter of Intent indicating both parties'
willingness to reach agreement on a contract for clinical lot production. Such a
letter will be accompanied by a payment of [CONFIDENTIAL TREATMENT REQUESTED]
/*/. Signature of both parties below will constitute a Letter of Intent between
Hollister-Stier Laboratories LLC and Acusphere, Inc. Hollister-Stier will
initiate this project and begin the purchase of long lead-time equipment upon a
signed copy of this letter and payment of [CONFIDENTIAL TREATMENT REQUESTED]
/*/.

Rider A (attached)

Sincerely,

/s/ Charles Moore

Charles Moore
Director, Contract Manufacturing

By signing this letter, both parties acknowledge a Letter of Intent between
Hollister-Stier Laboratories LLC and Acusphere, Inc. to fill Phase III AI-700 at
Hollister-Stier Laboratories LLC in Spokane, WA.

/s/ Charles Moore                                             8-16-10
Charles Moore                                                          Date
Director, Contract Manufacturing
Hollister-Stier Laboratories LLC

/s/ Howard Bernstein                                          08-20-01
Designee                                                               Date
Acusphere, Inc.

                                    Page 11
<PAGE>

                                     RIDER A

For the avoidance of doubt, the parties hereto acknowledge and agree that, other
than with respect to the provisions contained herein concerning the
[CONFIDENTIAL TREATMENT REQUESTED] /*/ down payment to be made by Acusphere upon
execution hereof (the "Down Payment"), this is a non-binding Letter of Intent,
is entered into in anticipation of entering into a binding CTM manufacturing
arrangement concerning the topics contained herein (a "Manufacturing Agreement")
and no legally binding obligations will be created, implied or inferred hereby.
The parties further acknowledge and agree that the Down Payment shall be
credited against future payments owed Hollister-Stier in connection with any
such Manufacturing Agreement, and if no such Manufacturing Agreement shall exist
as of September 10, 2001, the Down Payment shall be promptly returned to
Acusphere in full and Hollister-Stier will cease all Acusphere project activity
(subject to deduction for actual, documented expenses including Hollister-Stier
labor, contracted labor, facility modifications, purchased materials and any
applicable restock charges incurred by Hollister-Stier prior to September 10,
2001 in anticipation of entering into a Manufacturing Agreement).

                                    Page 12
<PAGE>

                                   Section #1

                     [CONFIDENTIAL TREATMENT REQUESTED] /*/

<PAGE>

                                   Section #2

                     [CONFIDENTIAL TREATMENT REQUESTED] /*/

<PAGE>

                                   Section #3

                     [CONFIDENTIAL TREATMENT REQUESTED] /*/

<PAGE>

                                   Section #4

                     [CONFIDENTIAL TREATMENT REQUESTED] /*/

<PAGE>

                                   Section #5

                     [CONFIDENTIAL TREATMENT REQUESTED] /*/

<PAGE>

                                   Section #6

                     [CONFIDENTIAL TREATMENT REQUESTED] /*/

<PAGE>

                                   Section #7

                     [CONFIDENTIAL TREATMENT REQUESTED] /*/

<PAGE>

                                   Section #8

                     [CONFIDENTIAL TREATMENT REQUESTED] /*/

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00056-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00056-of-00352.parquet"}]]