Dynavax Announces $30 Million At-The-Market Common Stock Purchase Agreement Aspire Capital Makes Initial Investment of $2 Million at $2.00 per Share

Exhibit 99.1

Dynavax Announces $30 Million At-The-Market Common Stock Purchase Agreement

Aspire Capital Makes Initial Investment of $2 Million at $2.00 per Share

BERKELEY, CA – September 20, 2010 – Dynavax Technologies Corporation (Nasdaq: DVAX) announced today that Aspire Capital Fund, LLC, an Illinois limited liability company, has purchased 1,000,000 shares of Dynavax common stock at $2.00 per share, representing a 23% premium to the closing market price on September 17, 2010. The investment was made in connection with a $30 million At-The-Market common stock purchase agreement under which Aspire Capital has committed to purchase up to an additional $28 million of Dynavax common stock over the next 25 months.

During the term of the purchase agreement, Dynavax will control the timing and amount of any sales of its common stock to Aspire Capital. Aspire Capital has no right to require any sales by the Company but is obligated to make purchases as the Company directs in accordance with the purchase agreement, which may be terminated by Dynavax at any time. Dynavax will use net proceeds from any sales of its stock to complete the Company’s development activities for its lead program, HEPLISAV™, an investigational hepatitis B vaccine, and for other general corporate purposes. Under the Purchase Agreement, the Company agreed to pay Aspire Capital a commitment fee equal to 4% of $30 million in consideration for Aspire Capital’s obligation to purchase up to $30 million of Dynavax common stock. Dynavax paid this commitment fee by issuance of 600,000 shares of its common stock valued at $2.00 per share. The Company did not pay any additional expense reimbursement or any placement agent fees in connection with the transaction. A more detailed description of the transaction agreements with Aspire Capital is set forth in the Company’s current report on Form 8-K, fil