Two Pralatrexate Studies Presented at the 50th Annual Meeting of the American Society of Hematology

  
    
  
  
    
      Allos Therapeutics, Inc. (Nasdaq:ALTH) today announced that results from 
      two pralatrexate (PDX) studies were presented as posters during the 50th 
      Annual Meeting of the American Society of Hematology (ASH), on December 
      6, 2008, in San Francisco, California. One poster reports interim data 
      from a Phase 1 trial of pralatrexate as a single agent in patients with 
      relapsed or refractory cutaneous T-cell lymphoma (CTCL). The second 
      poster reports interim data from a Phase 1/2a trial of pralatrexate in 
      combination with gemcitabine in patients with relapsed or refractory 
      non-Hodgkin's lymphoma (NHL) or Hodgkin's lymphoma.
    
    
      “We are encouraged by these interim data which suggest that pralatrexate 
      has activity when administered as a single agent in patients with CTCL 
      and in combination with gemcitabine in patients with lymphoma,” said 
      Pablo J. Cagnoni, M.D., Chief Medical Officer of Allos. “The studies 
      will continue with the objective of determining the optimal dose and 
      schedule for these indications.”
    
    
      Pralatrexate in CTCL (Phase 1)
    
    
      The poster (abstract 1569) entitled “Pralatrexate (PDX) is Active in 
      Cutaneous T-Cell Lymphoma: Preliminary Results of a Multi-center 
      Dose-finding Trial” presented interim data from the Company’s 
      ongoing Phase 1 trial of pralatrexate in patients with relapsed or 
      refractory CTCL. Data were presented on 24 patients, including 22 
      evaluable patients who completed at least one cycle of treatment at 
      doses ranging from 10-30 mg/m2 as part of a weekly schedule 
      for two or three weeks followed by one week of rest. Responses were 
      observed in 12 of 22 evaluable patients (55%), including one complete 
      response and 11 partial responses. Patients received a median of four 
      prior systemic therapies. The most common adverse event was mucosal 
      inflammation, with Grade 1/2 mucosal inflammation observed in 11 of 24 
      patients and Grade 3 mucosal inflammation observed in 4 of 24 patients. 
      There was no Grade 4 mucosal inflammation and no thrombocytopenia above 
      Grade 1. Up to 56 evaluable patients will be enrolled in the study with 
      the objective of determining the optimal dose and schedule for 
      pralatrexate in this patient population. Steven Horwitz, M.D., Assistant 
      Attending Physician, Lymphoma Service, Memorial Sloan-Kettering Cancer 
      Center, is the Principal Investigator of the study.
    
    
      Pralatrexate and Gemcitabine in 
      Lymphoproliferative Malignancies (Phase 1/2a)
    
    
      The poster (abstract 1570) entitled “A Phase 1/2a Open-label Study of 
      Pralatrexate and Gemcitabine in Patients with Relapsed or Refractory 
      Lymphoproliferative Malignancies” presented interim data from the 
      Company’s ongoing Phase 1/2a open-label, multi-center study of 
      pralatrexate in combination with gemcitabine in patients with relapsed 
      or refractory non-Hodgkin's lymphoma (NHL) or Hodgkin's lymphoma. Data 
      were presented on 27 patients, 22 of whom were evaluable for response. 
      Patients have been enrolled in eight cohorts with different doses and 
      schedules. Partial responses were observed in 6 of 22 evaluable 
      patients, including five patients on a sequential dosing schedule and 
      one patient on a same-day dosing schedule. Patients received a median of 
      three prior systemic regimens. The most common adverse event was 
      thrombocytopenia, with Grade 3 observed in four patients and Grade 4 
      observed in seven patients. The maximum tolerated dose for the 
      sequential dosing schedule was established as 10 mg/m2 of 
      pralatrexate followed by 300 mg/m2 of gemcitabine, once every 
      two weeks. Enrollment in the trial is ongoing to determine the maximum 
      tolerated dose for the same same-day dosing schedule. Dr. Horwitz is the 
      Principal Investigator of the study.
    
    
      Reprints of the posters will be available under the “Presentations” tab 
      of the “Investor Relations” section of the website (www.allos.com).
    
    
      About Pralatrexate (PDX)
    
    
      Pralatrexate is a novel 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. The Company believes 
      pralatrexate has the potential to be delivered as a single agent or in 
      combination therapy regimens.
    
    
      About Cutaneous T-Cell Lymphoma
    
    
      Cutaneous T-cells lymphomas, or CTCLs, are comprised of a number of 
      non-Hodgkin's T-cell lymphomas, including mycosis fungoides and Sezary 
      syndrome, which have their primary manifestations in the skin. According 
      to the Lymphoma Research Foundation, CTCL accounts for approximately 2% 
      to 3% of the estimated 63,000 new cases of non-Hodgkin's lymphoma 
      diagnosed each year in the United States. The Company estimates the 
      current annual prevalence of CTCL in the United States is between 16,000 
      and 20,000 cases.
    
    
      About Non-Hodgkin's Lymphoma
    
    
      Non-Hodgkin's lymphoma (NHL) is the most common hematological cancer and 
      the fifth leading cause of cancer death in the U.S. According to the 
      American Cancer Society, approximately 66,000 patients are expected to 
      be diagnosed with NHL in the United States in 2008.
    
    
      About Allos Therapeutics, Inc.
    
    
      Allos Therapeutics is a biopharmaceutical company focused on developing 
      and commercializing small molecule therapeutics for the treatment of 
      cancer. The Company's lead product candidate, pralatrexate, is a novel 
      antifolate currently under evaluation in a pivotal Phase 2 (PROPEL) 
      trial in patients with relapsed or refractory peripheral T-cell 
      lymphoma. The PROPEL trial is being conducted under an agreement reached 
      with the U.S. Food and Drug Administration under its special protocol 
      assessment, or SPA process. The Company is also investigating 
      pralatrexate in patients with non-small cell lung cancer, bladder cancer 
      and a range of lymphoma subtypes. The Company's other product 
      candidate is RH1, a targeted chemotherapeutic agent currently being 
      evaluated in a Phase 1 trial in patients with advanced solid tumors or 
      non-Hodgkin’s lymphoma (NHL). The Company currently retains exclusive 
      worldwide rights to pralatrexate and RH1 for all indications. For 
      additional information, please visit the Company’s website at www.allos.com.
    
    
      Safe Harbor Statement
    
    
      This press release contains forward-looking statements that are made 
      pursuant to the safe harbor provisions of the Private Securities 
      Litigation Reform Act of 1995. Such forward-looking statements include 
      statements concerning the potential activity of pralatrexate when 
      administered as a single agent in patients with CTCL and in combination 
      with gemcitabine in patients with lymphoma, and other statements which 
      are other than statements of historical facts. In some cases, you can 
      identify forward-looking statements by terminology such as “may,” 
      “will,” “should,” “expects,” “intends,” “plans,” anticipates,” 
      “believes,” “estimates,” “predicts,” “projects,” “potential,” 
      “continue,” and other similar terminology or the negative of these 
      terms, but their absence does not mean that a particular statement is 
      not forward-looking. Such forward-looking statements are not guarantees 
      of future performance and are subject to risks and uncertainties that 
      may cause actual results to differ materially from those anticipated by 
      the forward-looking statements. These risks and uncertainties include, 
      among others: that the Company may experience difficulties or delays in 
      the initiation, progress or completion of its clinical trials, whether 
      caused by competition, adverse events, investigative site initiation 
      rates, patient enrollment rates, regulatory issues or other factors; 
      that the interim data from the clinical trials discussed in this press 
      release may not be confirmed upon full analysis of the detailed results 
      of the trials, and may not be predictive of future clinical trial 
      designs or results; and that the Company may lack the financial 
      resources and access to capital to fund ongoing or planned clinical 
      trials for pralatrexate or any of its other product candidates, or to 
      continue evaluating their therapeutic utility in other potential 
      indications. Additional information concerning these 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 December 31, 2007, 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 this press release. All 
      forward-looking statements are based on information currently available 
      to the Company on the date hereof, 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.