Exhibit 99.1

JOINT FILING AGREEMENT

The undersigned hereby agree that the Statement on Schedule 13G dated June 5, 2009 with respect to the shares of Common Stock of Dynavax Technologies Corporation and any further amendments thereto executed by each and any of the undersigned shall be filed on behalf of each of the undersigned pursuant to and in accordance with the provisions of Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended.

Dated: June 5, 2009

BIOTECHNOLOGY VALUE FUND, L.P.			INVESTMENT 10, L.L.C.
By:		BVF Partners L.P., its general partner	By:	BVF Partners L.P., its investment manager
By:		BVF Inc., its general partner	By:	BVF Inc., its general partner
By:		/s/ Mark N. Lampert	By:	/s/ Mark N. Lampert
		Mark N. Lampert		Mark N. Lampert
		President		President
BIOTECHNOLOGY VALUE FUND II, L.P.			BVF PARTNERS L.P.
By:	BVF Partners L.P., its general partner		By:	BVF Inc., its general partner
By:	BVF Inc., its general partner		By:	/s/ Mark N. Lampert
				Mark N. Lampert
By:	/s/ Mark N. Lampert			President
	Mark N. Lampert
	President
			BVF INC.
BVF INVESTMENTS, L.L.C.			By:	/s/ Mark N. Lampert
				Mark N. Lampert
By:	BVF Partners L.P., its manager			President
By:	BVF Inc., its general partner
			/s/ Mark N. Lampert
By:	/s/ Mark N. Lampert		MARK N. LAMPERT
	Mark N. Lampert
	President