Spectrum Pharmaceuticals and Allos Therapeutics Announce That FTC Clears Transaction; Tender Offer for Shares of Allos Common Stock To Expire at 5pm Eastern Time on September 4, 2012

Spectrum Pharmaceuticals, Inc.

(Spectrum) and Allos Therapeutics, Inc.

(Allos) today announced that the Federal Trade Commission terminated the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, relating to the previously announced pending acquisition of all outstanding shares of common stock of Allos by Spectrum. As previously disclosed, Spectrum has commenced a tender offer to purchase all of the outstanding shares of common stock of Allos for $1.82 per share in cash, without interest and less any applicable withholding taxes. Spectrum intends to accept for payment shares of Allos common stock validly tendered and not withdrawn prior to