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8-K - FORM 8-K - AGENUS INCd8k.htm
EX-1.1 - AT MARKET ISSUANCE SALES AGREEMENT - AGENUS INCdex11.htm

Exhibit 5.1

March 1, 2010

Antigenics Inc.

3 Forbes Road

Lexington, MA 02421

 

Re: Registration Statement on Form S-3 (Registration No. 333-164481)

Ladies and Gentlemen:

This opinion is furnished to you in connection with the above-referenced registration statement filed with the Securities and Exchange Commission (the “Commission”) by Antigenics Inc., a Delaware corporation (the “Company”), on January 22, 2010 (the “Registration Statement”), the base prospectus dated February 3, 2010 (the “Base Prospectus”) and the prospectus supplement dated March 1, 2010 (together with the Base Prospectus, the “Prospectus”) filed with the Commission by the Company on March 1, 2010, pursuant to Rule 424 promulgated under the Securities Act of 1933, as amended. The Prospectus relates to the proposed issuance and sale from time to time of up to 20,000,000 shares of the Company’s common stock, par value $0.01 per share (the “Shares”), in accordance with the terms of an At Market Issuance Sales Agreement, dated February 26, 2010, by and between the Company and McNicoll, Lewis & Vlak LLC and Wm Smith & Co. (the “Agreement”).

We are familiar with the actions taken by the Company in connection with the proposed issuance of the Shares. For purposes of our opinion, we have examined and relied upon such documents, records, certificates, and other instruments as we have deemed necessary. The opinions expressed below are limited to the Delaware General Corporation Law, including the applicable provisions of the Delaware Constitution and the reported cases interpreting those laws.

Based on the foregoing, we are of the opinion that the Shares have been duly authorized and, when the Shares have been issued and sold in accordance with the terms of the Agreement and a Placement Notice (as defined in the Agreement) issued and accepted in accordance with the Agreement, the Shares will be validly issued, fully paid and nonassessable.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement. Our consent shall not be deemed an admission that we are experts whose consent is required under Section 7 of the Securities Act of 1933, as amended.

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