ALTH Allos Therapeutics, Inc. (MM)

Allos Therapeutics, Inc. (Nasdaq: ALTH) today announced that updated data from its pivotal Phase 2 PROPEL study of pralatrexate in patients with relapsed or refractory peripheral T-cell lymphoma will be presented at the 45th Annual Meeting of the American Society of Clinical Oncology (ASCO) to be held in Orlando, Fla., from May 29 to June�2, 2009.

The final results from the PROPEL study were reported in early February and formed the basis of the Company�s New Drug Application (NDA), which was submitted to the U.S. Food and Drug Administration (FDA) in March 2009. The poster presentation at ASCO will include analyses of response rate and durability of response, as well as overall survival.

Presentation details are as follows:

Date/Time:

� Saturday, May 30, 2009, 8:00 a.m. - 12:00 p.m. (Eastern)

Track:

Lymphoma and Plasma Cell Disorders

Poster Title:

PROPEL: Results of the Pivotal, Multi-center, Phase 2 Study of Pralatrexate in Patients with Relapsed or Refractory Peripheral T-cell Lymphoma (PTCL)

Abstract Number:

8561

Location:

Level 2, West Hall C, Poster Board R6 �

About Pralatrexate

Pralatrexate is a targeted antifolate designed to accumulate preferentially in cancer cells. Based on preclinical studies, the Company believes that pralatrexate selectively enters cells expressing RFC-1, a protein that is over-expressed on cancer cells compared to normal cells. Once inside cancer cells, pralatrexate is efficiently polyglutamylated, which leads to high intracellular drug retention. Polyglutamylated pralatrexate essentially becomes �trapped� inside cancer cells, making it less susceptible to efflux-based drug resistance. Acting on the folate pathway, pralatrexate interferes with DNA synthesis and triggers cancer cell death.

About Allos Therapeutics, Inc.

Allos Therapeutics is a biopharmaceutical company focused on developing and commercializing innovative small molecule drugs for the treatment of cancer. The Company�s lead product candidate, pralatrexate, is a novel targeted antifolate designed to accumulate preferentially in cancer cells. In February 2009, the Company announced the final results from PROPEL, the Company�s pivotal Phase 2 (PROPEL) trial of pralatrexate in patients with relapsed or refractory peripheral T-cell lymphoma (PTCL). The PROPEL trial was conducted under an agreement reached with the U.S. Food and Drug Administration under its special protocol assessment (SPA) process. Based on the results of the PROPEL trial, the Company submitted a New Drug Application to the U.S. Food and Drug Administration for pralatrexate for the treatment of relapsed or refractory PTCL in March 2009. The Company is also investigating pralatrexate in patients with non-small cell lung cancer, bladder cancer and a range of lymphoma sub-types. The Company currently retains exclusive worldwide rights to pralatrexate for all indications. For additional information, please visit www.allos.com.

Safe Harbor Statement

The anticipated presentation will contain forward-looking statements that involve significant risks and uncertainties. Additional information concerning these forward-looking statements and other factors that may cause actual results to differ materially from those anticipated in the forward-looking statements is contained in the "Risk Factors" section of the Company's Annual Report on Form 10-K for the year ended Dec. 31, 2008, and in the Company's other periodic reports and filings with the Securities and Exchange Commission. The Company cautions investors not to place undue reliance on the forward-looking statements contained in the presentation. All forward-looking statements are based on information currently available to the Company on the date thereof, and the Company undertakes no obligation to revise or update these forward-looking statements to reflect events or circumstances after the date of this presentation, except as required by law.