HENDERSON, Nev. & WESTMINSTER, Colo.--(BUSINESS WIRE)--Spectrum Pharmaceuticals, Inc. (NasdaqGS: SPPI) (Spectrum) and Allos Therapeutics, Inc. (NasdaqGS: ALTH) (Allos) today announced that the offer period in connection with Spectrum’s 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, expired at 5:00 p.m., Eastern time, on September 4, 2012.