EXHIBIT 5.1
ROPES & GRAY LLP THREE EMBARCADERO CENTER SAN FRANCISCO, CA 94111-4006 WWW.ROPESGRAY.COM |
December 15, 2011
Arrowhead Research Corporation
225 South Lake Avenue, 3rd Floor
Pasadena, CA 91101
Ladies and Gentlemen:
This opinion letter is furnished to you in connection with your filing of a Registration Statement on Form S-3 (the “Registration Statement”), with the Securities and Exchange Commission under the Securities Act of 1933, relating to the sale of up to 3,000,000 shares of common stock, $0.001 par value per share (the “Shares”), that may be issued by Arrowhead Research Corporation (the “Company”) to the selling stockholder, Lincoln Park Capital Fund, LLC (“LPC”). The Shares that may be offered by LPC pursuant to the prospectus contained in the Registration Statement are issuable pursuant to the Purchase Agreement between the Company and LPC, dated October 20, 2011 (the “Purchase Agreement”).
We have reviewed such documents and made such examination of law as we have deemed appropriate to give the opinions expressed below. We have relied, without independent verification, on certificates of public officials and, as to matters of fact material to the opinions set forth below, on certificates of officers of the Company.
The opinion expressed below is limited to the Delaware General Corporation Law (which includes applicable provisions of the Delaware Constitution and which includes judicial decisions interpreting the Delaware General Corporation Law and the Delaware Constitution).
For purposes of the opinion expressed below, we have assumed that a sufficient number of authorized but unissued shares of the Company’s common stock will be available for issuance when the Shares are issued.
Based on the foregoing, we are of the opinion that the Shares have been duly authorized and, upon issuance and delivery against payment therefor in accordance with the terms of the Purchase Agreement, will be validly issued, fully paid and non-assessable.
We hereby consent to the inclusion of this opinion as Exhibit 5.1 to the Registration Statement and to the references to our firm under the caption “Legal Matters” in the Registration Statement. In giving our consent, we do not admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations thereunder.
It is understood that this opinion is to be used only in connection with the offer and sale of Shares while the Registration Statement is in effect.
Very truly yours,
/s/ Ropes & Gray LLP
Ropes & Gray LLP