Exhibit 10.43

DYNAVAX TECHNOLOGIES CORPORATION

EQUITY DISTRIBUTION AGREEMENT

August 17, 2009

Wedbush Morgan Securities, Inc.

One Bush Street, Suite 1700

San Francisco, California 94104

Ladies and Gentlemen:

1. Introductory . Dynavax Technologies Corporation, a Delaware corporation (the “ Company ”), proposes, subject to the terms and conditions stated herein, to issue and sell through or to Wedbush Morgan Securities, Inc., as sales agent or principal (“ Wedbush ”), on the terms and subject to the conditions of this Equity Distribution Agreement (this “ Agreement ”), shares of its authorized but unissued common stock, par value $0.001 per share, having an aggregate gross sales price of up to $15 million (the “ Shares ”). The shares of common stock, par value $0.001 per share, of the Company to be outstanding after giving effect to the sales contemplated hereby are hereinafter referred to as the “ Common Stock ”.

The Company and Wedbush hereby confirm their agreement with respect to the issuance and sale of the Shares as follows:

2. Registration Statement and Prospectus . The Company has filed with the Securities and Exchange Commission (the “ Commission ”) a registration statement on Form S-3 (File No. 333-137608) under the Securities Act of 1933, as amended (the “ Act ”), and the rules and regulations of the Commission thereunder, and such amendments thereto (including post-effective amendments) as may be required to the date of this Agreement. Such registration statement, as amended (including any post-effective amendments), has been declared effective by the Commission. The registration statement as of its most recent effective date, including the information (if any) deemed to be part of the registration statement at the time of effectiveness pursuant to Rule 430A or Rule 430B under the Act, is hereinafter referred to as the “ Registration Statement ”, and the related base prospectus dated October 3, 2006 and filed as part of the Registration Statement, together with any amendments or supplements thereto as of the most recent effective date of the Registration Statement, is hereinafter referred to as the “ Basic Prospectus. ” “ Prospectus Supplement ” means the final prospectus supplement, relating to the Shares, filed by the Company with the Commission pursuant to Rule 424(b) under the Act on or before the second business day after the date hereof, in the form furnished by the Company to Wedbush in connection with the offering of the Shares. Except where the context otherwise requires, “ Prospectus ” means the Basic Prospectus, as supplemented by the Prospectus Supplement and the most recent Interim Prospectus Supplement (as defined in Section 7(c) below), if any. For purposes of this Agreement, “ free writing prospectus ” has the meaning set forth in Rule 405 under the Act. “ Permitted Free Writing Prospectuses ” means the documents listed on Schedule I hereto. As used herein, the terms “ Registration Statement ”, “ Basic Prospectus ”, “ Prospectus Supplement ”, “ Interim Prospectus Supplement ” and “ Prospectus ” shall include the documents, if any, incorporated by reference therein. The terms “ supplement ”, “ amendment ”, and “ amend ” as used herein with respect to the Registration Statement, the Basic Prospectus, the Prospectus Supplement, any Interim Prospectus Supplement, the Prospectus or any free writing prospectus shall include all documents subsequently filed by the Company with the Commission pursuant to the Securities Exchange Act of 1934, as amended (the “ Exchange Act ”), that are deemed to be incorporated by reference therein (the “ Incorporated Documents ”).

3. Sale of Shares. On the basis of the representations, warranties and agreements herein contained, but subject to the terms and conditions herein set forth, the Company and Wedbush agree that the Company may from time to time seek to sell Shares through Wedbush, acting as sales agent, or directly to Wedbush, acting as principal, as follows:

(a) The Company may submit its orders to Wedbush by telephone (including any price, time or size limits or other customary parameters or conditions) to sell Shares on any Trading Day (as defined herein) which order shall be confirmed by Wedbush (and accepted by the Company) by electronic mail using a form substantially similar to that attached hereto as Exhibit A . As used herein, “ Trading Day ” shall mean any trading day on the NASDAQ Capital Market (the “ Exchange ”), other than a day on which the Exchange is scheduled to close prior to its regular weekday closing time.

(b) Subject to the terms and conditions hereof, Wedbush shall use its commercially reasonable efforts to execute any Company order submitted to it hereunder to sell Shares and with respect to which Wedbush has agreed to act as sales agent. The Company acknowledges and agrees that (i) there can be no assurance that Wedbush will be successful in selling the Shares, (ii) Wedbush will incur no liability or obligation to the Company or any other person or entity if it does not sell Shares for any reason and (iii) Wedbush shall be under no obligation to purchase Shares on a principal basis pursuant to this Agreement, except as otherwise specifically agreed by Wedbush and the Company.

(c) Wedbush hereby covenants and agrees not to make any sales of the Shares on behalf of the Company other than as permitted by the terms of this Agreement.

(d) The Company shall not authorize the issuance and sale of, and Wedbush shall not sell as sales agent, any Share at a price lower than the minimum price therefor designated by the Company pursuant to Section 3(a) above. In addition, Wedbush or the Company may, upon notice to the other party hereto by telephone (confirmed promptly by email or facsimile), suspend an offering of the Shares with respect to which Wedbush is acting as sales agent; provided, however, that such suspension or termination shall not affect or impair the parties’ respective obligations with respect to the Shares sold hereunder prior to the giving of such notice.

(e) If acting as sales agent hereunder, Wedbush shall provide written confirmation (which may be by facsimile or email) to the Company following the close of trading on the Exchange each day in which Shares are sold under this Agreement setting forth (i) the amount of Shares sold on such day, (ii) the gross offering proceeds received from such sale and (iii) the commission payable by the Company to Wedbush with respect to such sales.

(f) At each Time of Sale, Settlement Date and Representation Date (as defined below), the Company shall be deemed to have affirmed each representation and warranty contained in this Agreement. Any obligation of Wedbush to use its commercially reasonable efforts to sell the Shares on behalf of the Company as sales agent shall be subject to the continuing accuracy of the representations and warranties of the Company herein, to the performance by the Company of its obligations hereunder and to the continuing satisfaction of the additional conditions specified in Section 9 of this Agreement.

(g) Notwithstanding any other provision of this Agreement, the Company and Wedbush agree that no sales of Shares shall take place, the Company shall not request the sales of any Shares that would be sold and Wedbush shall not be obligated to sell or offer to sell, during any period in which the Company’s insider trading policy, as it exists on the date of this Agreement,

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would prohibit the purchase or sale of Common Stock by persons subject to such policy, or during any other period in which the Company is in possession of material non-public information.

4. Fees and Expense Reimbursement.

(a) The compensation to Wedbush for sales of the Shares with respect to which Wedbush acts as sales agent hereunder shall be equal to 4% of the gross offering proceeds of the Shares sold pursuant to this Agreement. The Company may sell Shares to Wedbush as principal at a price agreed upon at the relevant Time of Sale.

(b) The Company shall from time to time reimburse Wedbush for its reasonable out-of-pocket expenses, including the reasonable fees and disbursements of counsel for Wedbush, incurred by Wedbush in connection with the transactions and other matters contemplated hereunder in an amount not to exceed $125,000 in the aggregate.

5. Delivery and Payment.

(a) Settlement for sales of the Shares pursuant to this Agreement will occur on the third Trading Day (or such earlier day as is industry practice for regular-way trading) following the date on which such sales are made (each such day, a “ Settlement Date ”). On each Settlement Date, the Shares sold through or to Wedbush for settlement on such date shall be issued and delivered by the Company to Wedbush against payment of the net proceeds from the sale of such Shares. Settlement for all such Shares shall be effected by free delivery of the Shares by the Company or its transfer agent (i) to Wedbush’s or its designee’s account (provided Wedbush shall have given the Company written notice of such designee prior to the Settlement Date) at The Depository Trust Company (“ DTC ”), (ii) through credit to the purchaser’s balance account with DTC through its Deposit Withdrawal Agent Commission system (provided Wedbush shall have given the Company written notice of account information prior to the Settlement Date), or (iii) by such other means of delivery as may be mutually agreed upon by the parties hereto, which in all cases shall be freely tradable, transferable, registered shares in good deliverable form, in return for payment in same day funds delivered to the account designated by the Company. If the Company, or its transfer agent (if applicable), shall default on its obligation to deliver the Shares on any Settlement Date, the Company shall (i) hold Wedbush harmless against any loss, claim, damage, or expense (including reasonable legal fees and expenses), as incurred, arising out of or in connection with such default by the Company and (ii) pay Wedbush any commission, discount or other compensation to which it would otherwise be entitled absent such default.

6. Representations and Warranties of the Company. The Company represents and warrants to, and agrees with, Wedbush that:

(a) Effectiveness of Registration Statement . The Registration Statement has become effective; no stop order suspending the effectiveness of the Registration Statement is in effect, and no proceedings for such purpose are pending before or threatened by the Commission.

(b) Compliance with Act Requirements. (i) (A) At the respective times the Registration Statement and each amendment thereto became effective, (B) at each deemed effective date with respect to Wedbush pursuant to Rule 430B(f)(2) under the Act (each, a “ Deemed Effective Time ”), (C) as of each time Shares are sold pursuant to this Agreement (each, a “ Time of Sale ”), (D) at each Settlement Date (as defined below) and (E) at all times during which a prospectus is required by the Act to be delivered (whether physically or through compliance with Rule 172 under the Act or any similar rule) in connection with any sale of

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Shares (the “ Delivery Period ”), the Registration Statement complied and will comply in all material respects with the requirements of the Act and the rules and regulations under the Act; (ii) the Basic Prospectus complied at the time it was filed with the Commission, complies as of the date hereof and, as of each Time of Sale and at all times during the Delivery Period, will comply in all material respects with the rules and regulations under the Act; (iii) each of the Prospectus Supplement, any Interim Prospectus Supplement and the Prospectus will comply, as of the date that it is filed with the Commission, as of each Time of Sale, as of each Settlement Date and at all times during the Delivery Period, in all material respects with the rules and regulations under the Act and (iv) the Incorporated Documents, when they were filed with the Commission, conformed in all material respects to the requirements of the Exchange Act and the rules and regulations of the Commission thereunder, and any further Incorporated Documents so filed and incorporated by reference, when they are filed with the Commission, will conform in all material respects to the requirements of the Exchange Act and the rules and regulations of the Commission thereunder.

(c) Absence of Material Misstatements and Omissions. (i) As of the date hereof, at the respective times the Registration Statement and each amendment thereto became effective and at each Deemed Effective Time, the Registration Statement did not and will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading; (ii) as of each Time of Sale, the Prospectus (as amended and supplemented at such Time of Sale) and any Permitted Free Writing Prospectus, considered together (collectively, the “ General Disclosure Package ”), did not contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; (iii) as of its date, the Prospectus did not contain an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; and (iv) at any Settlement Date, the Prospectus (as amended and supplemented at such Settlement Date) did not and will not contain an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that this representation and warranty shall not apply to any statements in or omissions from any such document based upon written information furnished to the Company by Wedbush, if any, specifically for use therein, it being understood and agreed that the only such information is that described as such in Section 9(b) hereof.

(d) Free Writing Prospectuses. Any free writing prospectus that the Company is required to file pursuant to Rule 433(d) under the Act has been, or will be, filed with the Commission in accordance with the requirements of the Act and the applicable rules and regulations of the Commission thereunder. Each free writing prospectus that the Company has filed, or is required to file, pursuant to Rule 433(d) under the Act or that was prepared by or on behalf of or used or referred to by the Company complies or will comply in all material respects with the requirements of the Act and the applicable rules and regulations of the Commission thereunder. Each free writing prospectus, as of its issue date and at all subsequent times through the completion of the public offer and sale of the Shares or until any earlier date that the Company notified or notifies Wedbush, did not, does not and will not include any material information that conflicted, conflicts or will conflict with the information contained in the Registration Statement or the Prospectus. Except for the Permitted Free Writing Prospectuses, if any, each furnished to Wedbush before first use, the Company has not prepared, used or referred to, and will not, without Wedbush’s prior consent, prepare, use or refer to, any free writing prospectus.

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(e) Not an “Ineligible Issuer”. (A) (i) At the time of filing the Registration Statement and (ii) at the time of the most recent amendment thereto for the purposes of complying with Section 10(a)(3) of the Act (whether such amendment was by post-effective amendment, incorporated report filed pursuant to Section 13 or 15(d) of the Exchange Act or form of prospectus), the Company was not an “ineligible issuer” as defined in Rule 405 of the Act; and (B) (i) at the time of filing of the Registration Statement, (ii) at the earliest time thereafter that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2) under the Act) of the Shares and (iii) at the date hereof, the Company was not and is not an “ineligible issuer” as defined in Rule 405 under the Act.

(f) Shelf Registration Statement. The date of this Agreement is not more than three years subsequent to the initial effective date of the Registration Statement.

(g) Good Standing of the Company and Its Subsidiary. The Company and the subsidiary of the Company listed on Schedule II attached hereto (the “ Subsidiary ”) has been duly incorporated and is existing and in good standing under the laws of their respective jurisdictions of organization, with power and authority (corporate and other) to own its respective properties and conduct its respective business as disclosed in the General Disclosure Package; and each of the Company and the Subsidiary is duly qualified to do business as a foreign corporation in good standing in all other jurisdictions in which its ownership or lease of property or the conduct of its business requires such qualification, except to the extent that the failure to be so qualified or be in good standing would not materially and adversely affect the Company or the Subsidiary or their respective businesses, properties, business prospects, conditions (financial or other) or results of operations, taken as a whole (such effect is referred to herein as a “ Material Adverse Effect ”). Except for the Subsidiary, the Company does not own any equity interest in any other entity. Except as disclosed in the General Disclosure Package and other than with respect to Symphony Dynamo, Inc., the Company has no “variable interests” in “variable interest entities,” as such terms are defined in Financial Accounting Standards Board Interpretation No. 46.

(h) Exchange Act Reports . The Company has filed in a timely manner all reports required to be filed pursuant to Sections 13(a), 13(e), 14 and 15(d) of the Exchange Act during the preceding 12 months.

(i) Capital Stock. The Shares to be issued and sold by the Company hereunder and all other outstanding shares of capital stock of the Company have been duly authorized; all outstanding shares of capital stock of the Company are, and, when the Shares of Common Stock have been delivered and paid for in accordance with this Agreement, such Shares will have been, validly issued, fully paid and nonassessable, and such Shares will conform to the information in the General Disclosure Package and to the description of such Shares contained in the Prospectus; the stockholders of the Company have no statutory or contractual preemptive rights with respect to the Common Stock; none of the outstanding shares of capital stock of the Company are or will have been issued in violation of any statutory or contractual preemptive rights of any security holder; and the authorized equity capitalization of the Company is as set forth in the General Disclosure Package. Except as disclosed in the General Disclosure Package, the Company owns all of the outstanding capital stock of the Subsidiary.

(j) No Finder’s Fee. There are no contracts, agreements or understandings between the Company and any person that would give rise to a valid claim against the Company or Wedbush for a brokerage commission, finder’s fee or other like payment.

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(k) Financial Statements . The financial statements and schedules included or incorporated by reference in the Registration Statement and the General Disclosure Package present fairly the financial condition of the Company and its consolidated Subsidiary as of the respective dates thereof and the results of operations and cash flows of the Company and its consolidated Subsidiary for the respective periods covered thereby, all in conformity with generally accepted accounting principles applied on a consistent basis throughout the entire period involved. No other financial statements or schedules of the Company are required by the Act, the Exchange Act, or the rules and regulations thereunder to be included in the Registration Statement or the General Disclosure Package. Ernst & Young LLP (the “ Accountant ”), who has reported on such financial statements and schedules, is an independent accountant with respect to the Company as required by the Act and the rules and regulations thereunder and Rule 3600T of the Public Company Accounting Oversight Board. The summary and selected consolidated financial and statistical data, if any, included in or incorporated by reference into the Registration Statement and the General Disclosure Package present fairly the information shown therein and have been compiled on a basis consistent with the Company’s audited financial statements.

(l) Absence of Changes. Subsequent to the respective dates as of which information is given in the General Disclosure Package, except as set forth in or contemplated by the General Disclosure Package, (i) there has not been any change in the capitalization of the Company (other than in connection with the grant or exercise of awards or options to purchase the Common Stock granted pursuant to the Company’s equity incentive plans from the shares reserved therefor), (ii) any Material Adverse Effect arising for any reason whatsoever, (iii) the Company has not incurred, except in the ordinary course of business as disclosed in the General Disclosure Package, any material liabilities or obligations, direct or contingent, the Company has not entered into, except in the ordinary course of business as disclosed in the General Disclosure Package, any material transactions other than pursuant to this Agreement and the transactions referred to herein and (iv) the Company has not paid or declared any dividends or other distributions of any kind on any class of its capital stock.

(m) Not An Investment Company . The Company is not, will not become as a result of the transactions contemplated hereby, an “investment company” or an “affiliated person” of, or “promoter” or “principal underwriter” for, an “investment company,” as such terms are defined in the Investment Company Act of 1940, as amended.

(n) Litigation . Except as disclosed in the General Disclosure Package, there are no actions, suits or proceedings pending or, to the knowledge of the Company, threatened against or affecting the Company or its Subsidiary or against any of their respective officers in their capacity as such, before or by any federal or state court, commission, regulatory body, administrative agency or other governmental body, domestic or foreign, wherein an unfavorable ruling, decision or finding would reasonably be expected to have a Material Adverse Effect.

(o) Absence of Existing Defaults and Conflicts . Except as disclosed in the General Disclosure Package, each of the Company and its Subsidiary is not (i) in violation of any provision of their respective certificates of incorporation or bylaws, (ii) in default in any respect, and no event has occurred which, with notice or lapse of time or both, would constitute such a default, in the due performance or observance of any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument to which it is a party or by which it is bound or to which any of its property or assets is subject, or (iii) in violation in any respect of any statute, law, rule, regulation, ordinance, judgment, order or decree of any court, regulatory body, administrative agency, governmental body, arbitrator or other authority having jurisdiction over the Company or the Subsidiary or any

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of their respective properties, as applicable, except, with respect to clauses (ii) and (iii), any violations or defaults which, individually or in the aggregate, would not reasonably be expected to have a Material Adverse Effect.

(p) Absence of Further Requirements . Except as disclosed in the General Disclosure Package, no consent, approval, authorization or order of, or any filing or declaration with, any court or governmental agency or body is required for the consummation by the Company of the transactions on its part contemplated herein, including the offering and sale of the Shares, except such as have been obtained under the Act or the rules and regulations thereunder and such as may be required under state securities or Blue Sky laws.

(q) Authorization; Absence of Defaults and Conflicts Resulting from Transaction . The Company has full corporate power and authority to enter into this Agreement. This Agreement has been duly authorized, executed and delivered by the Company. This Agreement is a valid and binding agreement of the Company, enforceable against the Company in accordance with its terms. The performance of this Agreement and the consummation of the transactions contemplated hereby, will not (i) result in the creation or imposition of any lien, charge or encumbrance upon any of the assets of the Company or the Subsidiary pursuant to the terms or provisions of, or result in a breach or violation of any of the terms or provisions of, or conflict with or constitute a default under, or give any party a right to terminate any of its obligations under, or result in the acceleration of any obligation under, (A) the certificate of incorporation or bylaws of the Company, or (B) any indenture, mortgage, deed of trust, voting trust agreement, loan agreement, bond, debenture, note agreement or other evidence of indebtedness, lease, contract or other agreement or instrument to which the Company or the Subsidiary is a party or by which the Company, the Subsidiary or any of their respective properties is bound or affected, except, in the case of clause (i)(B), any lien, breach, violation, conflict, default or acceleration that would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect, or