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                                                                     Exhibit 4.3

                        DYNAVAX TECHNOLOGIES CORPORATION

                   FOURTH AMENDED INVESTORS' RIGHTS AGREEMENT



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                                TABLE OF CONTENTS

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<S>  <C>        <C>                                                                                                         <C>
1.   GENERAL..................................................................................................................2
     1.1       Definitions....................................................................................................2

2.   REGISTRATION; RESTRICTIONS ON TRANSFER...................................................................................4
     2.1       Restrictions on Transfer.......................................................................................4
     2.2       Demand Registration............................................................................................5
     2.3       Piggyback Registrations........................................................................................6
     2.4       Form S-3 Registration..........................................................................................7
     2.5       Expenses of Registration.......................................................................................8
     2.6       Obligations of the Company.....................................................................................8
     2.7       Termination of Registration Rights............................................................................10
     2.8       Delay of Registration; Furnishing Information.................................................................10
     2.9       Indemnification...............................................................................................10
     2.10      Assignment of Registration Rights.............................................................................12
     2.11      Amendment of Registration Rights..............................................................................12
     2.12      Limitation on Subsequent Registration Rights..................................................................13
     2.13      "Market Stand-Off" Agreement..................................................................................13
     2.14      Rule 144 Reporting............................................................................................13

3.   COVENANTS OF THE COMPANY................................................................................................14
     3.1       Basic Financial Information and Reporting.....................................................................14
     3.2       Inspection and Other Rights...................................................................................15
     3.3       Confidentiality of Records....................................................................................15
     3.4       Board of Directors Approval...................................................................................16
     3.5       Preferred Stock Approval......................................................................................16
     3.6       Reservation of Common Stock...................................................................................16
     3.7       Vesting.......................................................................................................16
     3.8       Proprietary Information and Inventions Agreement..............................................................17
     3.9       Real Property Holding Corporation.............................................................................17
     3.10      Reimbursement of Expenses.....................................................................................17
     3.11      Indemnification...............................................................................................17
     3.12      Directors and Officers Insurance..............................................................................17
     3.13      Small Business Administration Matters.........................................................................17
     3.14      Termination of Covenants......................................................................................19

4.   RIGHTS OF FIRST REFUSAL.................................................................................................19
     4.1       Subsequent Offerings..........................................................................................19
     4.2       Exercise of Rights............................................................................................19
     4.3       Issuance of Equity Securities to Other Persons................................................................20
     4.4       Termination of Rights of First Refusal........................................................................20
     4.5       Transfer of Rights of First Refusal...........................................................................20
     4.6       Excluded Securities...........................................................................................20

5.   VOTING..................................................................................................................21
     5.1       Board of Directors............................................................................................21
</TABLE>


                                       -i-
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                                TABLE OF CONTENTS
                                   (continued)

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<S>  <C>        <C>                                                                                                         <C>
     5.2       Termination...................................................................................................21

6.   MISCELLANEOUS...........................................................................................................22
     6.1       Governing Law.................................................................................................22
     6.2       Arbitration...................................................................................................22
     6.3       Survival......................................................................................................22
     6.4       Successors and Assigns........................................................................................22
     6.5       Severability..................................................................................................23
     6.6       Amendment and Waiver..........................................................................................23
     6.7       Delays or Omissions...........................................................................................23
     6.8       Notices.......................................................................................................23
     6.9       Attorneys' Fees...............................................................................................23
     6.10      Titles and Subtitles..........................................................................................23
     6.11      Counterparts..................................................................................................24
</TABLE>


                                      -ii-

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                   FOURTH AMENDED INVESTORS' RIGHTS AGREEMENT

      THIS FOURTH AMENDED INVESTORS' RIGHTS AGREEMENT (this "Agreement") is
entered into as of October 20, 2003, by and among Dynavax Technologies
Corporation, a Delaware corporation (the "Company"), Dennis Carson and Eyal Raz
(the "Founders"), the purchasers of the Company's Series A Preferred Stock
("Series A Stockholders"), the purchasers of the Company's Series B Preferred
Stock ("Series B Stockholders"), the purchasers of the Company's Series C
Preferred Stock ("Series C Stockholders"), the purchasers of the Company's
Series D Preferred Stock ("Series D Stockholders") and the purchasers of
Ordinary Shares of Dynavax Asia Pte Ltd, a Singaporean corporation (the
"Subsidiary"; and such Ordinary Shares, the "Ordinary Shares")), which Ordinary
Shares are exchangeable for shares of the Company's Series E-1 Preferred Stock
or other capital stock of the Company pursuant to that certain Put/Call
Agreement, dated as of even date herewith, by and among the Company, the
Subsidiary and above-described purchasers (the "Put/Call Agreement") (the
above-described purchasers are sometimes referred to herein as "Rightsholders"
prior to exchange of their Subsidiary Ordinary Shares for the Company's
Preferred Stock pursuant to the Put/Call Agreement, and as "Series E-1
Stockholders" thereafter). This Agreement amends, restates and supersedes that
certain Third Amended Investors' Rights Agreement dated as of March 27, 2002, by
and among the Company, the Founders, the Series A Stockholders, the Series B
Stockholders, the Series C Stockholders and the Series D Stockholders (the
"Prior Agreement"). The Series A Stockholders, Series B Stockholders, Series C
Stockholders, Series D Stockholders, Rightsholders and Series E-1 Stockholders
shall be collectively referred to hereinafter as the "Investors" and each
individually as an "Investor."

                                    RECITALS

      A. WHEREAS, the Founders and certain of the Series A Stockholders, Series
B Stockholders, Series C Stockholders and Series D Stockholders hold Series A
Preferred Stock, Series B Preferred Stock, Series C Preferred Stock or Series D
Preferred Stock and/or shares of Common Stock issued upon conversion thereof and
possess registration rights, information rights and other rights pursuant to the
Prior Agreement;

      B. WHEREAS, the Founders, Series A Stockholders, Series B Stockholders,
Series C Stockholders and Series D Stockholders desire to amend the Prior
Agreement and to accept the rights created pursuant hereto in lieu of the rights
granted to them under the Prior Agreement;

      C. D. WHEREAS, the Company proposes to sell and issue shares of its
Preferred Stock pursuant to the Put/Call Agreement; and

      E. WHEREAS, as a condition of entering into the Put/Call Agreement, the
Rightsholders have requested that the Company extend to them registration
rights, information rights and other rights as set forth below.

      NOW, THEREFORE, in consideration of the mutual promises, representations,
warranties, covenants and conditions set forth in this Agreement and the
Put/Call Agreement, as applicable, the Founders, the Series A Stockholders,
Series B Stockholders, Series C


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Stockholders and Series D Stockholders who are parties to the Prior Agreement
hereby agree that the Prior Agreement shall be superseded and replaced in its
entirety by this Agreement, and the parties mutually agree as follows:

                                    AGREEMENT

1. GENERAL

      1.1 DEFINITIONS. As used in this Agreement, the following terms shall have
the following respective meanings:

      "AFFILIATE" of a person means a person controlling, controlled by, or
under common control with such person.

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

      "FORM S-3" means such form under the Securities Act as in effect on the
date hereof or any successor registration form under the Securities Act
subsequently adopted by the SEC which permits inclusion or incorporation of
substantial information by reference to other documents filed by the Company
with the SEC.

      "HOLDER" means any person owning of record Shares, Series E-1 Rights or
Registrable Securities, that have not been sold to the public or any assignee of
record of such Shares, Series E-1 Rights or Registrable Securities in accordance
with Section 2.10 hereof.

      "INITIAL OFFERING" means the Company's first firm commitment underwritten
public offering of its Common Stock registered under the Securities Act.

      "MAJOR INVESTOR" shall have the meaning given such term in Section 3.1(c)
hereof.

      "OTHER PREFERRED" shall mean the shares of Series R, Series S-1 and Series
T Preferred Stock of the Company.

      "PUT/CALL AGREEMENT" shall have the meaning given such term in the
preamble hereof.

      "QUALIFIED PUBLIC OFFERING" shall have the meaning given such term in
Section 2.2(a) hereof.

      "REGISTER," "REGISTERED," and "REGISTRATION" refer to a registration
effected by preparing and filing a registration statement in compliance with the
Securities Act, and the declaration or ordering of effectiveness of such
registration statement or document.

      "REGISTRABLE SECURITIES" means (i) Common Stock of the Company issued or
issuable upon conversion of the Shares; (ii) any Common Stock of the Company
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, such above-described securities and
(iii) Common Stock issuable upon exchange of the Series E-1 Rights pursuant to
the Put/Call Agreement. Notwithstanding the foregoing, Registrable


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Securities shall not include (a) any securities either sold by a person to the
public pursuant to a registration statement or Rule 144, (b) sold in a private
transaction in which the transferor's rights under Section 2 of this Agreement
are not assigned, and (c) the Ordinary Shares.

      "REGISTRABLE SECURITIES THEN OUTSTANDING" shall be the number of shares
determined by calculating the total number of shares of the Company's Common
Stock that are Registrable Securities and either (1) are then issued and
outstanding (2) are issuable pursuant to then exercisable or convertible
securities or (3) or are directly or indirectly issuable pursuant to the then
outstanding Series E-1 Rights.

      "REGISTRATION EXPENSES" shall mean all expenses incurred by the Company in
complying with Sections 2.2, 2.3 and 2.4 hereof, including, without limitation,
all registration and filing fees, printing expenses, fees and disbursements of
counsel for the Company, reasonable fees and disbursements of a single special
counsel for the Holders, blue sky fees and expenses and the expense of any
special audits incident to or required by any such registration (but excluding
fees and disbursements of additional counsel for any of the Holders, which fees
and disbursements shall be the obligations of such Holders, and excluding the
compensation of regular employees of the Company, which compensation shall be
paid in any event by the Company).

      "SEC" or "COMMISSION" means the Securities and Exchange Commission.

      "SERIES E-1 RIGHTS" means the rights of the Rightsholders to exchange the
Subsidiary's Ordinary Shares held by them for shares of the Company's Series E-1
Preferred Stock or other capital stock of the Company pursuant to the Put/Call
Agreement.

      "SECURITIES ACT" shall mean the Securities Act of 1933, as amended.

      "SELLING EXPENSES" shall mean all underwriting discounts and selling
commissions applicable to the sale of Shares pursuant to the Agreement.

      "SHARES" shall mean the Company's Series E-1 Preferred Stock (or other
capital stock of the Company) issued or issuable upon the exercise of Series E-1
Rights pursuant to the Put/Call Agreement, the Series A Preferred Stock, Series
B Preferred Stock, Series C Preferred Stock and Series D Preferred Stock
previously issued by the Company.

      "THRESHOLD OFFERING" means the Initial Offering at a price per share of at
least $4.12, with a total offering price, prior to deductions of underwriter
commissions, and offering expenses and the like, of at least thirty million
dollars ($30,000,000).

2. REGISTRATION; RESTRICTIONS ON TRANSFER

      2.1 RESTRICTIONS ON TRANSFER.

            (a) Each Holder agrees not to make any disposition of all or any
portion of the Shares, the Series E-1 Rights or Registrable Securities unless
and until:


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                  (i) There is then in effect a registration statement under the
Securities Act covering such proposed disposition, and such disposition is made
in accordance with such registration statement; or

                  (ii) (A) The transferee has agreed in writing to be bound by
the terms of this Agreement, (B) such Holder shall have notified the Company of
the proposed disposition and shall have furnished the Company with a detailed
statement of the circumstances surrounding the proposed disposition, and (C) if
reasonably requested by the Company, such Holder shall have furnished the
Company with an opinion of counsel, reasonably satisfactory to the Company, that
such disposition will not require registration of such securities under the
Securities Act or, in case of the Series E-1 Rights, any other applicable
securities laws. It is agreed that the Company will not require opinions of
counsel for transactions made pursuant to Rule 144 except in unusual
circumstances.

                  (iii) Notwithstanding the provisions of paragraphs (i) and
(ii) above, no such registration statement or opinion of counsel shall be
necessary for a transfer by a Holder which is (A) a partnership to its partners
or former partners in accordance with partnership interests, (B) a corporation
to its stockholders or affiliates in accordance with their interest in the
corporation, (C) a limited liability company to its members or former members in
accordance with their interest in the limited liability company, (D) to the
Holder's family member or trust for the benefit of an individual Holder or (E)
from a Holder to an Affiliate of such Holder provided such Affiliate complies
with Section 2.1(a)(ii)(A); provided in each case that the transferee will be
subject to the terms of this Agreement to the same extent as if it were an
original Holder hereunder.

            (b) Each certificate representing Shares or Registrable Securities
shall (unless otherwise permitted by the provisions of this Agreement) be
stamped or otherwise imprinted with a legend substantially similar to the
following (in addition to any legend required under applicable state securities
laws or as provided elsewhere in this Agreement):

      "THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF
1933. THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT AS TO THE SECURITIES UNDER SAID
ACT OR AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE COMPANY THAT SUCH
REGISTRATION IS NOT REQUIRED."

            (c) The Company shall be obligated to reissue promptly unlegended
certificates at the request of any holder thereof if the holder shall have
obtained an opinion of counsel (which counsel may be counsel to the Company)
reasonably acceptable to the Company to the effect that the securities proposed
to be disposed of may lawfully be so disposed of without registration,
qualification or legend.

            (d) Any legend endorsed on an instrument pursuant to applicable
state securities laws and the stop-transfer instructions with respect to such
securities shall be removed upon receipt by the Company of an order of the
appropriate blue sky authority authorizing such removal.


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      2.2 DEMAND REGISTRATION.

            (a) Subject to the conditions of this Section 2.2, if the Company
shall receive a written request from the Holders of more than twenty-five (25%)
of the Registrable Securities then outstanding (the "Initiating Holders") that
the Company file a registration statement under the Securities Act covering the
registration of Registrable Securities having an aggregate offering price to the
public in excess of five million dollars ($5,000,000) (a "Qualified Public
Offering"), then the Company shall, within thirty (30) days of the receipt
thereof, give written notice of such request to all Holders, and subject to the
limitations of this Section 2.2, use its best efforts to effect, as soon as
practicable, the registration under the Securities Act of all Registrable
Securities that the Holders request to be registered.

            (b) If the Initiating Holders intend to distribute the Registrable
Securities covered by their request by means of an underwriting, they shall so
advise the Company as a part of their request made pursuant to this Section 2.2
and the Company shall include such information in the written notice referred to
in Section 2.2(a). In such event, the right of any Holder to include its
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 the Company as provided in Section 2.6(e)) enter into an
underwriting agreement in customary form with the underwriter or underwriters
selected for such underwriting by a majority in interest of the Initiating
Holders (which underwriter or underwriters shall be reasonably acceptable to the
Company). Notwithstanding any other provision of this Section 2.2, if the
underwriter advises the Company that marketing factors require a limitation of
the number of securities to be underwritten (including Registrable Securities),
then the Company shall so advise all Holders of Registrable Securities which
would otherwise be underwritten pursuant hereto, and the number of shares that
may be included in the underwriting shall be allocated to the Holders of such
Registrable Securities on a pro rata basis based on the number of Registrable
Securities held by all such Holders (including the Initiating Holders);
provided, however, that, subject to any existing registration rights granted by
the Company, the number of Registrable Securities to be included in such
underwriting shall not be reduced unless all other securities proposed to be
included in such underwriting are first entirely excluded from such
underwriting. Any Registrable Securities excluded or withdrawn from such
underwriting shall be withdrawn from the registration.

            (c) The Company shall not be required to effect a registration
pursuant to this Section 2.2:

                  (i) until the earlier of December 31, 2004 or the date which
is six months after the Initial Offering; or

                  (ii) after the Company has effected three (3) registrations
pursuant to this Section 2.2, and such registrations have been declared or
ordered effective; or

                  (iii) during the period starting with the date of filing of,
and ending on the date one hundred eighty (180) days following the effective
date of, the registration statement


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pertaining to the Initial Offering; provided that the Company makes reasonable
good-faith efforts to cause such registration statement to become effective; or

                  (iv) if within thirty (30) days of receipt of a written
request from Initiating Holders pursuant to Section 2.2(a), the Company gives
notice to the Holders of the Company's intention to make its Initial Offering
within ninety (90) days; or

                  (v) if the Company shall furnish to Holders requesting a
registration statement pursuant to this Section 2.2, a certificate signed by the
Chairman of the Board or the President of the Company stating that in the
good-faith judgment of the Board of Directors of the Company, it would be
seriously detrimental to the Company and its stockholders for such registration
statement to be effected at such time, in which event the Company shall have the
right to defer such filing for a period of not more than one hundred twenty
(120) days after receipt of the request of the Initiating Holders; provided that
such right to delay a request shall be exercised by the Company not more than
once in any twelve (12) month period.

      2.3 PIGGYBACK REGISTRATIONS.

            (a) PIGGYBACK REGISTRATIONS. The Company shall notify all Holders in
writing at least thirty (30) days prior to the filing of any registration
statement under the Securities Act for purposes of a public offering of
securities of the Company (including, but not limited to, registration
statements relating to secondary offerings of securities of the Company, but
excluding registration statements relating to employee benefit plans or with
respect to corporate reorganizations or other transactions under Rule 145 of the
Securities Act), either for its own account or for the account of a security
holder or security holders, and the Company shall use its reasonable best
efforts to cause to be registered (subject to Section 2.3(b) below and the other
terms and conditions hereof) the Registrable Securities that such Holder has
requested to be registered. Each Holder desiring to include in any such
registration statement all or any part of the Registrable Securities held by it
shall, within fifteen (15) days after the above-described notice from the
Company, so notify the Company in writing. Such notice shall state the intended
method of disposition of the Registrable Securities by such Holder. If a Holder
decides not to include all of its Registrable Securities in any registration
statement thereafter filed by the Company, such Holder shall nevertheless
continue to have the right to include any Registrable Securities in any
subsequent registration statement or registration statements as may be filed by
the Company with respect to offerings of its securities, all upon the terms and
conditions set forth herein.

            (b) UNDERWRITING. If the registration statement under which the
Company gives notice under this Section 2.3 is for an underwritten offering, the
Company shall so advise the Holders. In such event, the right of any such Holder
to be included in a registration pursuant to this Section 2.3 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 Registrable
Securities through such underwriting shall enter into an underwriting agreement
in customary form with the underwriter or underwriters selected for such
underwriting by the Company. Notwithstanding any other provision of this
Agreement, if the underwriter determines in good faith that marketing factors
require a limitation of the number of shares to be underwritten, the number of
shares that may be


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included in the underwriting shall be allocated, first, to the Company; second,
to the Holders and persons holding registration rights with respect to the Other
Preferred on a pro rata basis based on the total number of Registrable
Securities proposed to be included by each Holder and such other persons in the
underwriting; and third, to any other stockholder of the Company (other than a
Holder or such other persons) on a pro rata basis; provided, however that no
such reduction shall reduce the securities being offered by the Holder to less
than 25% of the securities proposed to be sold by them in the offering unless
such offering is the Initial Offering. In no event will shares of any other
selling stockholder be included in such registration which would reduce the
number of shares which may be included by Holders without the written consent of
Holders of not less than a majority of the Registrable Securities proposed to be
sold in the offering.

            (c) RIGHT TO TERMINATE REGISTRATION. The Company shall have the
right to terminate or withdraw any registration initiated by it under this
Section 2.3 prior to the effectiveness of such registration whether or not any
Holder has elected to include securities in such registration. The Registration
Expenses of such withdrawn registration shall be borne by the Company in
accordance with Section 2.5 hereof.

      2.4 FORM S-3 REGISTRATION. In case the Company shall receive from any
Holder or Holders a written request or requests that the Company effect a
registration on Form S-3 (or any successor to Form S-3) or any similar
short-form registration statement and any related qualification or compliance
with respect to all or a part of the Registrable Securities owned by such Holder
or Holders, the Company will:

            (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 the Company;
provided, however, that the Company shall not be obligated to effect any such
registration, qualification or compliance pursuant to this Section 2.4:

                  (i) if Form S-3 (or any successor or similar form) is not
available for such offering by the Holders, or

                  (ii) if the Holders, together with the holders of any other
securities of the Company 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 One Million Dollars ($1,000,000), or

                  (iii) if the Company shall furnish to the Holders a
certificate signed by the Chairman of the Board of Directors or the President of
the Company stating that in the good-faith judgment of the Board of Directors of
the Company, it would be seriously detrimental to the Company and its
stockholders for such Form S-3 Registration to be effected at such time, in

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which event the Company shall have the right to defer the filing of the Form S-3
registration statement for a period of not more than ninety (90) days after
receipt of the request of the Holder or Holders under this Section 2.4;
provided, that such right to delay a request shall be exercised by the Company
not more than twice in any twelve (12) month period, or

                  (iv) if the Company has, within the twelve (12) month period
preceding the date of such request, already effected two (2) registrations on
Form S-3 for the Holders pursuant to this Section 2.4, or

                  (v) in any particular jurisdiction in which the Company would
be required to qualify to do business or to execute a general consent to service
of process in effecting such registration, qualification or compliance.

            (c) Subject to the foregoing, the Company shall file a Form S-3
registration statement covering the Registrable Securities so requested to be
registered as soon as practicable after receipt of the request or requests of
the Holders.

      2.5 EXPENSES OF REGISTRATION. All expenses of registration (exclusive of
underwriting discounts and commissions) including, without limitation, the fees
and expenses of one special counsel for the Holders for the demand, piggyback
and S-3 registrations shall be borne by the Company. All Selling Expenses
incurred in connection with any registrations hereunder shall be borne by the
holders of the securities so registered pro rata on the basis of the number of
shares so registered. The Company shall not, however, be required to pay for
expenses of any registration proceeding begun pursuant to Section 2.2, the
request of which has been subsequently withdrawn by the Initiating Holders,
unless (a) the withdrawal is based upon material adverse information concerning
the Company of which the Initiating Holders were not aware at the time of such
request, or (b) the Holders of a majority of Registrable Securities agree to
forfeit their right to one requested registration pursuant to Section 2.2, in
which event such right shall be forfeited by all Holders. If the Holders are
required to pay the Registration Expenses, such expenses shall be borne by the
Holders of securities (including Registrable Securities) requesting such
registration in proportion to the number of shares for which registration was
requested. If the Company is required to pay the Registration Expenses of a
withdrawn offering pursuant to clause (a) above, then the Holders shall not
forfeit their rights pursuant to Section 2.2 to a demand registration.

      2.6 OBLIGATIONS OF THE COMPANY. Whenever required to effect the
registration of any Registrable Securities, the Company shall, as expeditiously
as reasonably possible:

            (a) Prepare and file with the SEC a registration statement with
respect to such Registrable Securities and use all reasonable 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 up to one hundred twenty (120) days
or, if earlier, until the Holder or Holders have completed the distribution
related thereto; provided, however, that such period shall be extended for a
period of time equal to the period of time the Holder refrains from selling any
securities in such registration at the request of an underwriter.


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            (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
Securities Act with respect to the disposition of all securities covered by such
registration statement.

            (c) Furnish to the Holders such number of copies of a prospectus,
including a preliminary prospectus, in conformity with the requirements of the
Securities 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 reasonable 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 the Company 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.

            (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(s) 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 Securities Act 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) Furnish, at the request of any Holder participating in the
registration, on the date that such Registrable Securities are delivered to the
underwriters for sale, 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 as of such date, of the counsel representing the Company
for the purposes of such registration, in form and substance as is customarily
given to underwriters in an underwritten public offering and reasonably
satisfactory to such Holder requesting registration, addressed to the
underwriters, if any, and to such Holder requesting registration of Registrable
Securities and (ii) a letter dated as of such date, from the independent
certified public accountants of the Company, in form and substance as is
customarily given by independent certified public accountants to underwriters in
an underwritten public offering and reasonably satisfactory to such Holder
requesting registration, addressed to the underwriters, if any, and if permitted
by applicable accounting standards, to the Holders requesting registration of
Registrable Securities.

            (h) Use reasonable best efforts to cause all such Registrable
Securities registered hereunder to be listed on each securities exchange or
quotation system on which the same securities issued by the Company are then
listed.


                                       9
<PAGE>
      2.7 TERMINATION OF REGISTRATION RIGHTS. All registration rights granted
under this Section 2 shall terminate and be of no further force and effect after
the earlier of (i) three (3) years after the date of the Company's Initial
Offering, or (ii) the date when the Company has completed its Initial Offering
and is subject to the provisions of the Exchange Act and all Registrable
Securities held by and issuable to such Holder may be sold during any ninety
(90) day period under Rule 144 (or successor rule promulgated by the SEC, other
than under Rule 144(k)).

      2.8 DELAY OF REGISTRATION; FURNISHING INFORMATION.

            (a) 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.

            (b) It shall be a condition precedent to the obligations of the
Company to take any action pursuant to Section 2.2, 2.3 or 2.4 that the selling
Holders shall furnish to the Company such information regarding themselves, the
Registrable Securities held by them and the intended method of disposition of
such securities as shall be required to effect the registration of their
Registrable Securities.

            (c) The Company shall have no obligation with respect to any
registration requested pursuant to Section 2.2 if, due to the operation of
subsection 2.2(b), the number of shares or the anticipated aggregate offering
price of the Registrable Securities to be included in the registration does not
equal or exceed the number of shares or the anticipated aggregate offering price
required to originally trigger the Company's obligation to initiate such
registration as specified in Section 2.2, whichever is applicable.

      2.9 INDEMNIFICATION. In the event any Registrable Securities are included
in a registration statement under Section 2.2, 2.3 or 2.4:

            (a) To the extent permitted by law, the Company will indemnify and
hold harmless each Holder, the partners, officers, directors and legal counsel
of each Holder, any underwriter (as defined in the Securities Act) for such
Holder and each person, if any, who controls such Holder or underwriter within
the meaning of the Securities Act or the Exchange Act, against any losses,
claims, damages, or liabilities (joint or several) to which they may become
subject under the Securities Act, the Exchange 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") by the Company: (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 the Company of the Securities Act,
the Exchange Act, any state securities law or any rule or regulation promulgated
under the Securities Act, the Exchange Act or any state securities law in
connection with the offering covered by such registration statement; and the
Company will reimburse each such Holder, partner, officer or director,
underwriter or controlling person for any legal or other expenses


                                       10
<PAGE>
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 Section 2.9(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 the Company, which consent shall
not be unreasonably withheld, nor shall the Company 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 such Holder, partner, officer, director, underwriter
or controlling person of such Holder.

            (b) To the extent permitted by law, each Holder will, if Registrable
Securities held by such Holder are included in the securities as to which such
registration, qualification or compliance is being effected, indemnify and hold
harmless the Company, each of its directors, each of its officers, and legal
counsel and each person, if any, who controls the Company within the meaning of
the Securities Act, any underwriter and any other Holder selling securities
under such registration statement or any of such other Holder's partners,
directors or officers or any person who controls such Holder, against any
losses, claims, damages or liabilities (joint or several) to which the Company
or any of the foregoing persons may become subject under the Securities Act, the
Exchange 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 under an instrument duly executed by such
Holder and stated to be specifically for use in connection with such
registration; and each such Holder will reimburse any legal or other expenses
reasonably incurred by the Company or any such director, officer, legal counsel,
controlling person, underwriter or other Holder, or partner, officer, director
or controlling person of such other Holder in connection with investigating or
defending any such loss, claim, damage, liability or action if it is judicially
determined that there was such a Violation; provided, however, that the
indemnity agreement contained in this Section 2.9(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 further, that in no event shall any
indemnity under this Section 2.9 exceed the net proceeds from the offering
received by such Holder.

            (c) Promptly after receipt by an indemnified party under this
Section 2.9 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 2.9, deliver to
the indemnifying party a written notice of the commencement thereof, and the
indemnifying party shall have the right to participate therein, 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 shall
have the right to retain its own counsel, with the fees and expenses to be paid
by the indemnifying party, if representation of such indemnified party by the
counsel retained by the indemnifying party would be inappropriate due to actual
or potential differing interests between such indemnified party and any other
party represented by such counsel in such proceeding. The failure to deliver
written notice to the indemnifying party within a reasonable time of the
commencement of any such action, if materially prejudicial to its


                                       11
<PAGE>
ability to defend such action, shall relieve such indemnifying party of any
liability to the indemnified party under this Section 2.9, 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 2.9.

            (d) If the indemnification provided for in this Section 2.9 is held
by a court of competent jurisdiction to be unavailable to an indemnified party
with respect to any losses, claims, damages or liabilities referred to herein,
the indemnifying party, in lieu of indemnifying such indemnified party
thereunder, shall to the extent permitted by applicable law contribute to the
amount paid or payable by such indemnified party as a result of such loss,
claim, damage, expense or liability 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 Violation(s) that resulted
in such loss, claim, damage or liability, 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 no event shall any contribution by a
Holder hereunder exceed the net proceeds from the offering received by such
Holder giving rise to such loss, liability, claim, damage or expense.

            (e) The obligations of the Company and Holders under this Section
2.9 shall survive completion of any offering of Registrable Securities in a
registration statement. No indemnifying party, in the defense of any such claim
or litigation, shall, except with the consent of each indemnified party, consent
to entry of any judgment or enter into any settlement which does not include as
an unconditional term thereof the giving by the claimant or plaintiff to such
indemnified party of a release from all liability in respect of such claim or
litigation.

      2.10 ASSIGNMENT OF REGISTRATION RIGHTS. The rights to cause the Company to
register Registrable Securities pursuant to this Section 2 may be assigned by a
Holder to a transferee or assignee of Registrable Securities which (i) is a
subsidiary, parent, general partner, limited partner or retired partner of a
Holder, (ii) is a Holder's family member or trust for the benefit of an
individual Holder, (iii) is an Affiliate of such Holder, or (iv) acquires at
least fifty thousand (50,000) shares of Registrable Securities (as adjusted for
stock splits and combinations); provided, however, (A) the transferor shall,
within ten (10) days after such transfer, furnish to the Company 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, and (B) such
transferee shall agree in writing to be subject to all restrictions set forth in
this Agreement.

      2.11 AMENDMENT OF REGISTRATION RIGHTS. Any provision of this Section 2 may
be amended and the observance thereof may be waived (either generally or in a
particular instance and either retroactively or prospectively), only with the
written consent of the Company and the Holders of at least two-thirds (66 2/3%)
of the Registrable Securities then outstanding. Any amendment or waiver effected
in accordance with this Section 2.11 shall be binding upon each Holder and the
Company. By acceptance of any benefits under this Section 2, Holders of
Registrable Securities hereby agree to be bound by the provisions hereunder.


                                       12
<PAGE>
      2.12 LIMITATION ON SUBSEQUENT REGISTRATION RIGHTS. From and after the date
of this Agreement, the Company shall not, without the prior written consent of
the Holders of two-thirds (66-2/3%) of the Registrable Securities then
outstanding, enter into any agreement with any holder or prospective holder of
any securities of the Company which would grant such holder registration rights
equal to or senior to those of the Holders of Registrable Securities.

      2.13 "MARKET STAND-OFF" AGREEMENT. If requested by the Company or the
representative of the underwriters of Common Stock (or other securities) of the
Company, each Holder shall not sell or otherwise transfer or dispose of any
Common Stock (or other securities) of the Company held by such Holder (other
than those included in the registration) for a period specified by the
representative of the underwriters not to exceed one hundred eighty (180) days
following the effective date of a registration statement of the Company filed
under the Securities Act; and such Holder shall enter into a reasonable, written
lock-up agreement to that effect if requested by the Company or the
representative of the underwriters; provided that:

                  (i) such agreement shall apply only to the Company's Initial
Offering; and

                  (ii) all officers and directors of the Company and holders of
at least one percent (1%) of the Company's voting securities enter into similar
agreements.

      The obligations described in this Section 2.13 shall not apply to a
registration relating solely to employee benefit plans on Form S-1 or Form S-8
or similar forms that may be promulgated in the future, or a registration
relating solely to a Commission Rule 145 transaction on Form S-4 or similar
forms that may be promulgated in the future. The Company may impose
stop-transfer instructions with respect to the shares of Common Stock (or other
securities) subject to the foregoing restriction until the end of said one
hundred eighty (180) day period.

      2.14 RULE 144 REPORTING. With a view to making available to the Holders
the benefits of certain rules and regulations of the SEC which may permit the
sale of the Registrable Securities to the public without registration, the
Company agrees to use its reasonable best efforts to:

            (a) make and keep public information available, as those terms are
understood and defined in SEC Rule 144 or any similar or analogous rule
promulgated under the Securities Act, at all times after the effective date of
the first registration filed by the Company for an offering of its securities to
the general public;

            (b) file with the SEC, in a timely manner, all reports and other
documents required of the Company under the Exchange Act; and

            (c) so long as a Holder owns any Registrable Securities, furnish to
such Holder forthwith upon request: (i) a written statement by the Company as to
its compliance with the reporting requirements of said Rule 144 of the
Securities Act, and of the Exchange Act (at any time after it has become subject
to such reporting requirements) or with respect to its status qualifying as a
registrant whose securities may be resold pursuant to Form S-3; (ii) a copy of
the most recent annual or quarterly report of the Company; and (iii) such other
reports and


                                       13
<PAGE>
documents as a Holder may reasonably request in availing itself of any rule or
regulation of the SEC allowing it to sell any such securities without
registration.

3. COVENANTS OF THE COMPANY

      3.1 BASIC FINANCIAL INFORMATION AND REPORTING.

            (a) The Company will maintain true books and records of account in
which full and correct entries will be made of all its business transactions
pursuant to a system of accounting established and administered in accordance
with generally accepted accounting principles consistently applied, and will set
aside on its books all such proper accruals and reserves as shall be required
under generally accepted accounting principles consistently applied.

            (b) As soon as practicable after the end of each fiscal year of the
Company, the Company will furnish each Investor a consolidated balance sheet of
the Company, as at the end of such fiscal year, and a consolidated statement of
income and a consolidated statement of cash flows of the Company, for such year,
all prepared in accordance with generally accepted accounting principles
consistently applied and setting forth in each case in comparative form the
figures for the previous fiscal year, all in reasonable detail. Such financial
statements shall be audited and accompanied by a report and opinion thereon by
independent public accountants of national standing selected by the Company's
Board of Directors.

            (c) The Company will furnish each Investor, as soon as practicable
after the end of the first, second and third quarterly accounting periods in
each fiscal year of the Company (and in any event within forty-five (45) days
thereafter), a consolidated balance sheet of the Company as of the end of each
such quarterly period, and a consolidated statement of income and a consolidated
statement of cash flows of the Company for such period and for the current
fiscal year to date, prepared in accordance with generally accepted accounting
principles, with the exception that such statements may be unaudited, no notes
need be attached to such statements and year-end audit adjustments may not have
been made.

            (d) So long as an Investor (with its Affiliates) shall own at least
five hundred thousand (500,000) shares of Registrable Securities (as adjusted
for stock splits, combinations and similar events) (a "Major Investor"), the
Company will furnish each such Major Investor and each Series D Stockholder
(regardless of whether such Series D Stockholder is a Major Investor) (i) at
least thirty (30) days prior to the beginning of each fiscal year an annual
operating plan for such fiscal year (and as soon as available, any subsequent
revisions thereto), (ii) as soon as practicable after the end of each month (and
in any event within twenty (20) days thereafter), a consolidated balance sheet
of the Company as of the end of each such month, and a consolidated statement of
income and a consolidated statement of cash flows of the Company for such month
and for the current fiscal year to date, including a comparison to plan figures
for such period, prepared in accordance with generally accepted accounting
principles consistently applied, with the exception that such statements may be
unaudited, no notes need be attached to such statements and year-end audit
adjustments may not have been made and (iii) within not more than one hundred
twenty (120) days after the end of each fiscal year, audited financial
statements of the Company.


                                       14
<PAGE>
            (E) The rights granted to the Investors under this Section 3.1 shall
terminate upon the effective date of the registration statement pertaining to
the Threshold Offering.

      3.2 INSPECTION AND OTHER RIGHTS. Each Major Investor and each Series D
Stockholder (regardless of whether such Series D Stockholder is a Major
Investor) shall have the right to visit and inspect any of the properties of the
Company or any of its subsidiaries, and to consult with and advise the officers
of the Company with respect to significant business issues, the finances and
accounts of the Company or any of its subsidiaries, and to review such
information as is reasonably requested, all at such reasonable times and as
often as may be reasonably requested; provided, however, that the Company shall
not be obligated under this Section 3.2 with respect to a competitor of the
Company or with respect to information which the Board of Directors determines
in good faith is confidential and should not, therefore, be disclosed. The
rights granted to the Major Investors and Series D Stockholders under this
Section 3.2 are nonassignable and shall terminate upon the effective date of the
registration statement pertaining to the Initial Offering.

      3.3 CONFIDENTIALITY OF RECORDS. Each Investor agrees to use, and to use
its best commercially reasonable efforts to ensure that its authorized
representatives use, the same degree of care as such Investor uses to protect
its own confidential information to keep confidential any information furnished
to it which the Company identifies as being confidential (so long as such
information is not in the public domain), except that such Investor may disclose
such confidential information to any partner, officer, subsidiary or parent of
such Investor for the purpose of evaluating its investment in the Company as
long as such partner, officer, subsidiary or parent is advised of the
confidentiality provisions of this Section 3.3. For purposes of this Section 3.3
"confidential information" does not include information, technical data or
know-how which (i) is in the Investor's possession at the time of initial
disclosure as shown by the Investor's files and records immediately prior to the
time of such disclosure; (ii) before or after it has been disclosed to the
Investor, is part of the public knowledge or literature, not as a result of any
action or inaction of the Investor; or (iii) is approved for release by written
authorization of the Company. The provisions of this Section 3.3 shall not apply
(i) to the extent that an Investor is required to disclose confidential
information pursuant to any law, statute, rule or regulation or any order of any
court of competent jurisdiction or pursuant to any requirement (whether or not
having the force of law, but if not having the force of law, being of a type
with which institutional investors in the relevant jurisdiction are accustomed
to comply) of any self-regulating organization or any governmental, fiscal,
monetary or other authority; or (ii) to the disclosure of confidential
information to an Investor's employees, counsel, accountants or other
professional advisors, provided such persons agree to be bound by this Section
3.3.

      3.4 BOARD OF DIRECTORS APPROVAL.

            (a) The Company shall not without the approval of a majority of the
Board of Directors take any of the following actions:

                  (i) adopt any stock option or purchase plan;

                  (ii) issue or grant any equity securities of the Company or
any options or securities convertible into equity securities of the Company;


                                       15
<PAGE>
                  (iii) adopt an annual budget, business or financial plan;

                  (iv) enter into any material real estate lease or real
property purchase agreement; or

                  (v) incur any obligation or enter into any agreement in excess
of one hundred thousand dollars ($100,000), not otherwise provided for in the
Company's most recent annual budget or business plan as approved by the Board of
Directors.

            (b) The Company shall not without the approval of at least
two-thirds of the Board of Directors enter into any transaction with an
affiliate (except for the Subsidiary).

      3.5 PREFERRED STOCK APPROVAL. The Company shall not change its line of
business without the approval of a majority of the Series A Stockholders, Series
B Stockholders, Series C Stockholders, Series D Stockholders and Series E-1
Stockholders (together with the Series E-2 Preferred Stock as applicable in
accordance with the Company's Certificate of Incorporation, as it may be
amended) voting together as a single class, on an as converted to Common Stock
basis.

      3.6 RESERVATION OF COMMON STOCK. The Company will at all times reserve and
keep available, solely for issuance and delivery upon the conversion of the
Preferred Stock, all Common Stock issuable from time to time upon such
conversion.

      3.7 VESTING. Unless otherwise approved by the Board of Directors, all
stock, stock options and other stock equivalents of the Company issued on or
after the date of this Agreement to employees, directors, consultants and other
service providers shall be subject to vesting as follows: (i) twenty-five
percent (25%) of such stock (or underlying stock, as the case may be) shall vest
at the end of the first year following the earlier of the date of issuance or
such person's services commencement date with the Company, and (ii) seventy-five
percent (75%) of such stock (or underlying stock, as the case may be) shall vest
monthly in equal portions over the ensuing three (3) years. With respect to any
shares of stock purchased by any such person, the Company's repurchase option
shall provide that upon such person's termination of employment or service with
the Company, with or without cause, the Company or its assignee (to the extent
permissible under applicable securities laws and other laws) shall have the
option to purchase at cost any unvested shares of stock held by such person.

      3.8 PROPRIETARY INFORMATION AND INVENTIONS AGREEMENT. The Company shall
require all employees and consultants to execute and deliver a Proprietary
Information and Inventions Agreement in the forms attached to the Purchase
Agreement.

      3.9 REAL PROPERTY HOLDING CORPORATION. The Company covenants that it will
operate in a manner such that it will not become a "United States real property
holding corporation" ("USRPHC") as that term is defined in Section 897(c)(2) of
the Internal Revenue Code of 1986, as amended, and the regulations thereunder
("FIRPTA"). The Company agrees to make determinations as to its status as a
USRPHC, and will file statements concerning those determinations with the
Internal Revenue Service, in the manner and at the times required under Reg.
Section 1.897-2(h), or any supplementary or successor provision thereto. Within
30 days of a request from an Investor or any of its partners, the Company will
inform the requesting party, in the manner set forth in Reg. Section
1.897-2(h)(1)(iv) or any supplementary or successor provision


                                       16
<PAGE>
thereto, whether that party's interest in the Company constitutes a United
States real property interest (within the meaning of Internal Revenue Code
Section 897(c)(1) and the regulations thereunder) and whether the Company has
provided to the Internal Revenue Service all required notices as to its USRPHC
status.

      3.10 REIMBURSEMENT OF EXPENSES. The Company will reimburse the Directors
of the Company for reasonable out-of-pocket expenses actually incurred in
connection with their services to the Company as Directors, including without
limitation, reimbursement for reasonable transportation, lodging and meal
expenses incurred in connection with attendance at meetings of the Board of
Directors, provided the Company receives receipts and other records of such
expenses as reasonably requested by the Company and within sixty (60) days after
expenses are incurred.

      3.11 INDEMNIFICATION. The Company will use its reasonable efforts to limit
the liability, to the fullest extent permissible under the Delaware General
Corporation Law, of all of its directors and their affiliated parties, including
directors affiliated with a Major Investor.

      3.12 DIRECTORS AND OFFICERS INSURANCE. The Company shall maintain
directors' and officers' insurance satisfactory to the Board of Directors of the
Company.

      3.13 SMALL BUSINESS ADMINISTRATION MATTERS.

                  (i) The proceeds from the purchase of the Series D Preferred
Stock pursuant to the Series D Preferred Stock Purchase Agreement, as amended,
dated July 24, 2002, by and among the Company and the Series D Stockholders (the
"Series D Purchase Agreement") shall be used by the Company for working capital
and other general corporate purposes, which may include, without limitation, one
or more of the following as determined by the Company in its sole discretion:
research, development, administration, manufacturing, marketing, sales and
distribution. The Company shall provide to representatives of the Investors and
the Small Business Administration (the "SBA") reasonable access to its books and
records for the purpose of confirming such use of the proceeds or for other
purposes reasonably related to the qualification of the financing provided by
the Investors to the Company.

                  (ii) For a period of one (1) year following the Closing (as
defined in the Series D Purchase Agreement), the Company shall not change the
nature of its business activity if such change would render the Company
ineligible, within the meaning of 13 C.F.R. Section 107.720.

                  (iii) So long as the Investors hold any securities of the
Company, the Company will comply at all times with the non-discrimination
requirements of 13 C.F.R. Parts 112, 113 and 117.

                  (iv) Upon the written request of the Investors, and with the
cooperation of such Investors, the Company shall deliver to the Investors a
written assessment, in form and substance reasonably satisfactory to the
Investors, of the economic impact of the Investors' investment in the Company,
specifying (a) the full-time equivalent jobs created or retained in


                                       17
<PAGE>
connection with the investment, and (b) the impact of the investment on the
Company's business, in terms of revenue and profits, and on taxes paid by the
Company and its employees. Upon request, the Company promptly (and in any event
within twenty (20) days of such request) shall furnish to the Investors all
information (a) reasonably requested by them in order for the Investors to
comply with the requirements of 13 C.F.R. Section 107.620 or to prepare and file
SBA Form 468 and (b) reasonably requested or required by any United States
governmental agency asserting jurisdiction over the Investors. Any submission of
financial information pursuant to this Section 3.13 shall be under cover of a
certificate executed by the Company's president, chief executive officer, chief
financial officer or treasurer certifying that such information (i) relates to
the Company, (ii) to the best of the Company's knowledge is accurate and (iii)
if applicable, has been audited by the Company's independent auditors.

                  (v) In the event that any of the Investors determines that it
has a Regulatory Problem (as defined below), it shall have the right, subject to
compliance with all applicable federal and state securities laws, (i) to
transfer its Series B Preferred Stock, Series C Preferred Stock, Series D
Preferred Stock or Series E-1 Preferred Stock without regard to any restrictions
on transfer set forth in this Agreement, provided that the transferee agrees to
become a party to and to be bound by all of the provisions of each such
agreement, and (ii) to require the Company to take all actions as may be
reasonably requested by the Investor, as the case may be, in order to (A)
effectuate and facilitate any transfer by the Investor of its Series B Preferred
Stock, Series C Preferred Stock, Series D Preferred Stock or Series E-1
Preferred Stock then held by it to any person designated by the Investor, (B)
permit the Investor (or any of its affiliates) to exchange all or any portion of
any voting securities of the Company then held by the Investor (or any
affiliate), on a share-for-share basis, for non-voting securities of the
Company, which non-voting securities shall be identical in all respects to the
voting security exchanged therefor (except for voting rights and that the
non-voting securities shall be convertible or exchangeable for voting securities
on such terms as may be appropriate in light of regulatory considerations then
prevailing), and (iii) amend this Agreement to effectuate and reflect the
foregoing exchange described in subclause (ii) above. The parties to this
Agreement shall be required under this Section to take any action that would
adversely affect in any material economic respect such party's rights under this
Agreement or as a stockholder of the Company. For purposes of this Section, a
"Regulatory Problem" means any set of facts or circumstances wherein both (i) it
has been asserted by any governmental regulatory agency with jurisdiction over
an Investor that the Investor is not entitled to hold, or exercise any
significant right with respect to, the Series B Preferred Stock, Series C
Preferred Stock, the Series D Preferred Stock or Series E-1 Preferred Stock or
the currently unissued Common Stock of the Company into which the Series B
Preferred Stock, Series C Preferred Stock, Series D Preferred Stock, or Series
E-1 Preferred Stock is convertible, and (ii) the Investor reasonably determines
that such assertion is meritorious and that the solution proposed by the
Investor is necessary to cure such regulatory violation by the Investor.

                  (vi) So long as any Investor that is a licensed Small Business
Investment Company (a "SBIC Investor") holds any securities of the Company, the
Company shall notify each SBIC Investor (i) at least fifteen (15) days prior to
taking any action after which the number of record holders of the Company's
voting securities would be increased from fewer than fifty (50) to fifty (50) or
more, and (ii) of any other action or occurrence after which the number of
record holders of the Company's voting securities was increase (or would
increase)


                                       18
<PAGE>
from fewer than fifty (50) to fifty (50) or more, as soon as practicable after
the Company becomes aware that such other action or occurrence has occurred or
is proposed to occur.

      3.14 TERMINATION OF COVENANTS. All covenants of the Company contained in
Section 3 of this Agreement, except for that set forth in Sections 3.10, 3.11
and 3.13(iv), shall expire and terminate as to each Investor on the effective
date of the registration statement pertaining to the Initial Offering.

4. RIGHTS OF FIRST REFUSAL

      4.1 SUBSEQUENT OFFERINGS. Each Investor and each Founder (each of such
Investors and Founders, for purposes of this Section 4, an "Owner") shall have a
right of first refusal to purchase its pro rata share of all Equity Securities,
as defined below, that the Company may, from time to time, propose to sell and
issue after the date of this Agreement, other than the Equity Securities
excluded by Section 4.6 hereof. Each Owner's pro rata share, for purposes of
this right of first refusal, is equal to the ratio of (A) the number of shares
of the Company's Common Stock (including all shares of Common Stock issued or
issuable upon conversion of the Shares or exercise of outstanding warrants or
options) of which such Owner is deemed to be a holder immediately prior to the
issuance of such Equity Securities to (B) the total number of shares of the
Company's outstanding Common Stock (including all shares of Common Stock issued
or issuable upon conversion of the Shares or upon the exercise of any
outstanding warrants or options) immediately prior to the issuance of the Equity
Securities held by all Owners. The term "Equity Securities" shall mean (i) any
Common Stock, Preferred Stock or other security of the Company, (ii) any
security convertible, with or without consideration, into any Common Stock,
Preferred Stock or other security (including any option to purchase such a
convertible security), (iii) any security carrying any warrant or right to
subscribe to or purchase any Common Stock, Preferred Stock or other security or
(iv) any such warrant or right.

      4.2 EXERCISE OF RIGHTS. If the Company proposes to issue any Equity
Securities, it shall give each Owner written notice of its intention, describing
the Equity Securities, the price per share and the terms and conditions upon
which the Company proposes to issue the Equity Securities. Each Owner shall have
twenty (20) days from the giving of such notice to agree to purchase up to its
pro rata share of the Equity Securities for the price per share and upon the
terms and conditions specified in the notice by giving written notice to the
Company and stating therein the quantity of Equity Securities to be purchased.
Notwithstanding the foregoing, the Company shall not be required to offer or
sell such Equity Securities to any Owner who would cause the Company to be in
violation of applicable federal securities laws by virtue of such offer or sale.

      4.3 ISSUANCE OF EQUITY SECURITIES TO OTHER PERSONS. If not all of the
Owners elect to purchase their full pro rata share of the Equity Securities,
then the Company shall promptly notify in writing the Owners who do so elect and
shall offer such Owners the right to acquire such unsubscribed shares. Each
Owner shall have ten (10) days after receipt of such notice to notify the
Company of its election to purchase all or a portion of the unsubscribed shares.
If the Owners fail to exercise in full the rights of first refusal, the Company
shall have sixty (60) days thereafter to sell the Equity Securities in respect
of which the Owners' rights were not exercised, at a price and upon general
terms and conditions materially no more favorable to the purchasers


                                       19
<PAGE>
thereof than specified in the Company's notice to the Owners pursuant to Section
4.2 hereof. If the Company has not sold such Equity Securities within sixty (60)
days of the notice provided pursuant to Section 4.2, the Company shall not
thereafter issue or sell any Equity Securities, without first offering such
securities to the Owners in the manner provided above.

      4.4 TERMINATION OF RIGHTS OF FIRST REFUSAL. The rights of first refusal
established by this Section 4 shall not apply to Equity Securities offered for
sale in the Initial Offering, and such rights shall terminate upon the effective
date of the registration statement pertaining to the Threshold Offering.

      4.5 TRANSFER OF RIGHTS OF FIRST REFUSAL. The rights of first refusal of
each Owner under this Section 4 may be transferred, subject to the same
limitations and restrictions as any transfer of registration rights pursuant to
Section 2.10 (as necessarily modified to apply to the Founders and/or Common
Stock).

      4.6 EXCLUDED SECURITIES. The rights of first refusal established by this
Section 4 shall have no application to any of the following Equity Securities in
a transaction or transactions approved by a majority of the Board of Directors:

            (a) shares of Common Stock (and/or options, warrants or other Common
Stock purchase rights issued pursuant to such options, warrants or other rights)
issued or to be issued to employees, officers or directors of, or consultants or
advisors to, the Company or any subsidiary, pursuant to stock purchase or stock
option plans or other arrangements;

            (b) stock issued pursuant to any rights or agreements outstanding as
of the date of this Agreement, options and warrants outstanding as of the date
of this Agreement, and stock issued pursuant to any such rights or agreements
granted after the date of this Agreement, provided that the rights of first
refusal established by this Section 4 applied with respect to the initial sale
or grant by the Company of such rights or agreements;

            (c) any Equity Securities issued for consideration other than cash
pursuant to a merger, consolidation, acquisition or similar business
combination;

            (d) shares of Common Stock issued in connection with any stock
split, stock dividend or recapitalization by the Company;

            (e) the Shares and any shares of Common Stock issued upon conversion
of the Shares;

            (f) any Equity Securities issued pursuant to any equipment leasing
arrangement, or debt financing from a bank or similar financial institution;

            (g) any Equity Securities issued by the Company pursuant to a
registration statement filed under the Securities Act;

            (h) shares of the Company's Common Stock or Preferred Stock issued
in connection with strategic transactions involving the Company and other
entities, including (A)


                                       20
<PAGE>
joint ventures, manufacturing, marketing or distribution arrangements, or (B)
technology transfer or development arrangements; and

            (i) The Series E-1 Rights and any capital stock of the Company
issued pursuant to the Series E-1 Rights or conversion of such capital stock
into Common Stock.

5. VOTING

      5.1 BOARD OF DIRECTORS. At each annual or special meeting of the
stockholders of the Company, called for purposes of electing directors of the
Company, and at any other time at which the stockholders of the Company shall
have the right to, or shall, vote for or consent in writing to the election of
directors of the Company, then in each such event, the Investors and Founders
agree that they shall vote all shares of Company stock owned by them or
hereafter acquired or which such stockholder may be empowered to vote directly
or indirectly (including with respect to all voting rights provided pursuant to
the Series E-1 Preferred Stock or Series E-2 Preferred Stock, and in the case
such rights are held in trust to cause the trustee to so vote) for the election
of the Board of Directors in the following manner: (i) to elect three (3)
representatives nominated by the holders of a majority of the shares of Series A
Preferred and Series B Preferred then outstanding on an as-converted to Common
Stock basis); (ii) to elect two (2) representatives nominated by the holders of
a majority of the shares of Series D Preferred, then outstanding; provided that
one of which shall be designated by Care Capital LLC; (iii) to elect a Founder,
nominated by the holders of a majority of the then outstanding Common Stock;
(iv) to elect the then current chief executive officer; and (v) at the
discretion of the Board of Directors, to elect two (2) representatives who are
not employees of the Company or any Investor, nominated or appointed by a
majority of the Board of Directors. A vacancy in any directorship entitled to be
elected by the holders of record of a particular class or series of capital
stock of the Company shall be filled only by vote or written consent of the
holders of record of such particular class or series of capital stock entitled
to elect such director, as set forth in this section. Any director who has been
elected as provided for in this section may be removed, with or without cause,
only by the holders of record of a majority of the shares of such class or
series of capital stock entitled to nominate or elect such director.

      5.2 TERMINATION. The provisions of this Section 5 shall continue in full
force and effect from the date hereof through the earliest of the following
dates, upon which their effectiveness shall terminate in their entirety:

            (a) the effective date of the registration statement pertaining to
the Initial Offering; or

            (b) at such time as the Investors hold Shares having the voting
power equivalent to that of a number of shares of Common Stock less than five
million (5,000,000) (as adjusted for stock splits, combinations and similar
events); or

            (c) upon the conversion into shares of Common Stock of all of the
outstanding shares of (i) the Series A Preferred Stock, (ii) Series B Preferred
Stock, (iii) Series C Preferred Stock, (iv) Series D Preferred Stock and (v) the
Series E-1 Preferred Stock or other preferred stock of the Company issued in
exchange for the Ordinary Shares pursuant to the


                                       21
<PAGE>
Put/Call Agreement (or the exchange of all Ordinary Shares subject to the
Put/Call Agreement for capital stock of the Company if such exchange is not for
Series E-1 or other preferred stock of the Company);

            (d) ten (10) years from the date of this Agreement;

            (e) the date as of which the parties hereto terminate the
effectiveness of this Section 5 by written consent of the Founders and a
majority in interest of the Investors;

6. MISCELLANEOUS

      6.1 GOVERNING LAW. This Agreement and all acts and transactions pursuant
hereto and the rights and obligations of the parties hereto shall be governed,
construed and interpreted in accordance with the laws of the State of
California, except to the extent the General Corporation Law of the State of
Delaware applies, without giving effect to principles of conflicts of law.

      6.2 ARBITRATION. The parties agree that any and all disputes, claims or
controversies arising out of or relating to this Agreement that are not resolved
by their mutual agreement shall be submitted to final and binding arbitration
before JAMS, or its successor, pursuant to the United States Arbitration Act, 9
U.S.C. Sec. 1 et seq. Any party may commence the arbitration process called for
in this agreement by filing a written demand for arbitration with JAMS, with a
copy to the other party. The arbitration will be conducted in accordance with
the provisions of JAMS' Streamlined Arbitration Rules and Procedures in effect
at the time of filing of the demand for arbitration. The parties will cooperate
with JAMS and with one another in selecting an arbitrator from JAMS' panel of
neutrals, and in scheduling the arbitration proceedings. The parties covenant
that they will participate in the arbitration in good faith, and that they will
share equally in its costs. The provisions of this Section 6.2 may be enforced
by any court of competent jurisdiction, and the party seeking enforcement shall
be entitled to an award of all costs, fees and expenses, including attorneys
fees, to be paid by the party against whom enforcement is ordered.

      6.3 SURVIVAL. The representations, warranties, covenants, and agreements
made herein shall survive any investigation made by any Holder and the closing
of the transactions contemplated hereby. All statements as to factual matters
contained in any certificate or other instrument delivered by or on behalf of
the Company pursuant hereto in connection with the transactions contemplated
hereby shall be deemed to be representations and warranties by the Company
hereunder solely as of the date of such certificate or instrument.

      6.4 SUCCESSORS AND ASSIGNS. Except as otherwise expressly provided herein,
the provisions hereof shall inure to the benefit of, and be binding upon, the
successors, assigns, heirs, executors, and administrators of the parties hereto
and shall inure to the benefit of and be enforceable by such persons; provided,
however, that prior to the receipt by the Company of adequate written notice of
the transfer of any Registrable Securities specifying the full name and address
of the transferee, the Company may deem and treat the person listed as the
Holder of such Registrable Securities in its records as the absolute owner and
Holder of such Registrable Securities for all purposes, including the payment of
dividends or any redemption price.


                                       22
<PAGE>
      6.5 SEVERABILITY. In case any provision of this Agreement shall be
invalid, illegal, or unenforceable, the validity, legality, and enforceability
of the remaining provisions shall not in any way be affected or impaired
thereby.

      6.6 AMENDMENT AND WAIVER. Except as otherwise expressly provided, the
obligations of the Company and the rights of the parties hereto may be amended,
modified or waived only with the written consent of the holders of at least
two-thirds (66 2/3%) of the Registrable Securities then outstanding and the
Company. Notwithstanding the foregoing, this Agreement may be amended with only
the written consent of the Company to include additional purchasers of Shares as
"Investors," "Holders" and parties hereto.

      6.7 DELAYS OR OMISSIONS. It is agreed that no delay or omission to
exercise any right, power, or remedy accruing to any Holder, upon any breach,
default or noncompliance of the Company under this Agreement, shall impair any
such right, power, or remedy, nor shall it be construed to be a waiver of any
such breach, default or noncompliance, or any acquiescence therein, or of any
similar breach, default or noncompliance thereafter occurring. It is further
agreed that any waiver, permit, consent, or approval of any kind or character on
any Holder's part of any breach, default or noncompliance under the Agreement or
any waiver on such Holder's part of any provisions or conditions of this
Agreement must be in writing and shall be effective only to the extent
specifically set forth in such writing. All remedies, either under this
Agreement, by law, or otherwise afforded to Holders, shall be cumulative and not
alternative.

      6.8 NOTICES. All notices required or permitted hereunder shall be in
writing and shall be deemed effectively given: (i) upon personal delivery to the
party to be notified, (ii) when sent by confirmed telex or facsimile if sent
during normal business hours of the recipient; if not, then on the next business
day, (iii) five (5) days after having been sent by registered or certified mail,
return receipt requested, postage prepaid, or (iv) one (1) 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 current address of the Investor on the books and
records of the Company or at such other address as such party may designate by
ten (10) days' advance written notice to the other parties hereto. All notices
sent to the Company shall also be sent to: Morrison & Foerster LLP, 425 Market
Street, San Francisco, CA 94105, Attention: John Campbell, Esq. (Telecopier:
(415) 268-7522).

      6.9 ATTORNEYS' FEES. In the event that any dispute among the parties to
this Agreement should result in litigation, the prevailing party in such dispute
shall be entitled to recover from the losing party all fees, costs and expenses
of enforcing any right of such prevailing party under or with respect to this
Agreement, including without limitation, such reasonable fees and expenses of
attorneys and accountants, which shall include, without limitation, all fees,
costs and expenses of appeals.

      6.10 TITLES AND SUBTITLES. The titles of the sections and subsections of
this Agreement are for convenience of reference only and are not to be
considered in construing this Agreement.

      6.11 COUNTERPARTS. This Agreement may be executed in any number of
counterparts, each of which shall be an original, but all of which together
shall constitute one instrument.


                                       23
<PAGE>
                      [THIS SPACE INTENTIONALLY LEFT BLANK]


                                       24
<PAGE>
      IN WITNESS WHEREOF, the parties hereto have executed this FOURTH AMENDED
INVESTORS' RIGHTS AGREEMENT as of the date set forth in the first paragraph
hereof.

                                        COMPANY:

                                        DYNAVAX TECHNOLOGIES CORPORATION

                                        By: /s/ Dino Dina
                                           -------------------------------------
                                             Dino Dina
                                             President & Chief Executive Officer

                                        Address:
                                        Dynavax Technologies Corporation
                                        717 Potter Street, Suite 100
                                        Berkeley, CA 94710
                                        Attn:  Chief Financial Officer
                                        Facsimile:  510-450-7740

        SIGNATURE PAGE TO THE FOURTH AMENDED INVESTORS' RIGHTS AGREEMENT
<PAGE>
                                        INVESTOR:

                                        BIOMEDICAL SCIENCES INVESTMENT FUND
                                        PTE LTD

                                        By: /s/ Lily Chan
                                           -------------------------------------
                                             Lily Chan, PhD
                                             Director

                                        Address:
                                        250 North Bridge Road
                                        #27-04 Raffles City Tower
                                        Singapore 179101
                                        Facsimile: +65-3348478

        SIGNATURE PAGE TO THE FOURTH AMENDED INVESTORS' RIGHTS AGREEMENT
<PAGE>
                                        INVESTOR:

                                        BIOVEDA FUND PTE LTD.

                                        By: BIOVEDA CAPITAL PTE LTD,
                                            its Investment Manager

                                        By: /s/ Damien Lim
                                           -------------------------------------
                                             Damien Lim
                                             General Partner

                                        Address:
                                        BioVeda Fund Pte Ltd.
                                        50 Cuscaden Road #08-01
                                        HPL House
                                        Singapore 249724
                                        SINGAPORE
                                        Facsimile: 65-6733-3832

        SIGNATURE PAGE TO THE FOURTH AMENDED INVESTORS' RIGHTS AGREEMENT
<PAGE>
                                        INVESTOR:

                                        SANDERLING VENTURE PARTNERS V CO-
                                        INVESTMENT FUND, L.P.

                                        By: MIDDLETON, MCNEIL & MILLS ASSOCIATES
                                            V, LLC

                                        By:  /s/ Robert G. McNeil
                                           -------------------------------------
                                             Robert G. McNeil
                                             Managing Director

                                        SANDERLING V BIOMEDICAL CO-INVESTMENT
                                        FUND, L.P.

                                        By: MIDDLETON, MCNEIL & MILLS ASSOCIATES
                                            V, LLC

                                        By:  /s/ Robert G. McNeil
                                           -------------------------------------
                                             Robert G. McNeil
                                             Managing Director

                                        SANDERLING V LIMITED PARTNERSHIP

                                        By: MIDDLETON, MCNEIL & MILLS ASSOCIATES
                                            V, LLC

                                        By:  /s/ Robert G. McNeil
                                           -------------------------------------
                                             Robert G. McNeil
                                             Managing Director

                                        SANDERLING V BETEILIGUNGS GMBH & CO. KG

                                        By: MIDDLETON, MCNEIL & MILLS ASSOCIATES
                                            V, LLC

                                        By:  /s/ Robert G. McNeil
                                           -------------------------------------
                                             Robert G. McNeil
                                             Managing Director

                                        SANDERLING V VENTURES MANAGEMENT

                                        By:  /s/ Robert G. McNeil
                                           -------------------------------------
                                             Robert G. McNeil
                                             Owner

        SIGNATURE PAGE TO THE FOURTH AMENDED INVESTORS' RIGHTS AGREEMENT
<PAGE>
                                        INVESTOR:

                                        CARE CAPITAL INVESTMENTS II, LP

                                        By:  CARE CAPITAL II, LLC,
                                             as general partner of Care Capital
                                             Investments II, LP

                                        By: /s/ David R. Ramsey
                                           -------------------------------------
                                        Name: David R. Ramsey
                                             -----------------------------------
                                        Title: Authorized Signatory
                                              ----------------------------------

                                        Address: 47 Hulfish St.
                                                 Suite 310
                                                 Princeton, NJ 08542

                                        Attn: David Ramsey
                                        Facsimile: 609-683-5787

        SIGNATURE PAGE TO THE FOURTH AMENDED INVESTORS' RIGHTS AGREEMENT
<PAGE>
                                        INVESTOR:

                                        PIPER JAFFRAY HEALTHCARE FUND III, L.P.

                                        By: PIPER JAFFRAY HEALTHCARE MANAGEMENT
                                            III, L.P., its General Partner

                                        By: /s/ Kenneth E. Higgins
                                           -------------------------------------
                                        Kenneth E. Higgins, Managing Director of
                                        Piper Ventures Capital, Inc., its
                                        General Partner

                                        Address:
                                        Ken Higgins
                                        U.S. Bancorp Piper Jaffray Ventures Inc.
                                        800 Nicollet Mall, Suite 800
                                        Minneapolis, MN 55402-7020
                                        Phone:  (612) 303-6365
                                        Fax:  (612) 303-1350
                                        khiggins@pjc.com

        SIGNATURE PAGE TO THE FOURTH AMENDED INVESTORS' RIGHTS AGREEMENT
<PAGE>
                                        INVESTOR:

                                        QFINANCE, INC.

                                        By: /s/ John S. Russell
                                           -------------------------------------
                                        Name: John S. Russell
                                             -----------------------------------
                                        Title: Exec. VP - General Counsel
                                              ----------------------------------

                                        Address: 4709 Creekstone Drive
                                                 Durham, NC 27703
                                        Attn: Tom Perkins
                                        Facsimile: 919-998-2542
                                                  -----------------

        SIGNATURE PAGE TO THE FOURTH AMENDED INVESTORS' RIGHTS AGREEMENT
<PAGE>
                                        INVESTOR:

                                        EMERGING TECHNOLOGY PARTNERS, LLC

                                        By: /s/ William F. Snider
                                           -------------------------------------
                                        Name: William F. Snider

                                        Title: Managing Director

                                        Address:   1901 Research Blvd.
                                                   Suite 350
                                                   Rockville, MD 20850

                                        Attn:
                                        Facsimile: 301-222-2221

        SIGNATURE PAGE TO THE FOURTH AMENDED INVESTORS' RIGHTS AGREEMENT
<PAGE>
                                             AXIOM VENTURE PARTNERS II, L.P.


                                             By: /s/ Alan Mendelson
                                                --------------------------------
                                             Name: Alan Mendelson
                                                  ------------------------------
                                             Title: General Partner
                                                   -----------------------------

                                             Address:

                                             Attn:
                                             Facsimile:

        SIGNATURE PAGE TO THE FOURTH AMENDED INVESTORS' RIGHTS AGREEMENT