Spectrum Pharmaceuticals and Allos Therapeutics Announce Extension of Previously Announced Tender Offer For Shares of Allos Therapeutics

Spectrum Pharmaceuticals, Inc.

and Allos Therapeutics, Inc.

(Allos) today announced that, on May 9, 2012, each had received from the Federal Trade Commission (FTC) a Request for Additional Information and Documentary Material (Second Request) under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, applicable to the acquisition of Allos by Spectrum. Both parties are continuing to cooperate with the FTC. In accordance with the Agreement and Plan of Merger dated April 4, 2012 among Spectrum, Allos and Sapphire Acquisition Sub, Inc., as a result of the Second Request, Spectrum has extended the offer period of its previously announced 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, plus one Contingent Value Right, which entitles Allos stockholders to an additional payment of $0.11 per share in cash if certain European regulatory approval and commercialization milestones for FOLOTYN® are achieved. The offer, which was previously scheduled to expire at 12:00 midnight, Eastern time, at the end of the day on Thursday, May 10, 2012, has been extended until 5:00 p.m., Eastern time, on May 24, 2012, unless extended for an additional period. All terms and conditions of the tender offer shall remain unchanged during the extended period.