CUSIP NO. 042564203 Page 10 of 12 Pages

EXHIBIT A

JOINT FILING AGREEMENT

The undersigned hereby agree that the Schedule 13G with respect to the Common Stock, par value $0.0001 per share, of Arno Therapeutics, Inc., dated as of November 8, 2013, is, and any amendments thereto (including amendments on Schedule 13D) signed by each of the undersigned shall be, filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934.

Date: November 8, 2013	SOROS FUND MANAGEMENT LLC
	By:	/s/ Jay Schoenfarber
		Jay Schoenfarber
		Deputy General Counsel
Date: November 8, 2013	GEORGE SOROS
	By:	/s/ Jay Schoenfarber
		Jay Schoenfarber
		Attorney-in-Fact
Date: November 8, 2013	ROBERT SOROS
	By:	/s/ Jay Schoenfarber
		Jay Schoenfarber
		Attorney-in-Fact