Data From Phase 3 Trial of Allos Therapeutics' RSR13 (efaproxiral) Presented at ASCO NEW ORLEANS, June 6 /PRNewswire-FirstCall/ -- Allos Therapeutics, Inc. (ALTH) announced that results from its Phase 3 clinical trial of the investigational radiation sensitizer RSR13 (efaproxiral) in patients with brain metastases were presented in a poster session on Saturday at the 40th Annual Meeting of the American Society of Clinical Oncology. Preliminary results from the Phase 3 study, called REACH, were first announced in April 2003. John H. Suh, M.D., Clinical Director, Radiation Oncology, Brain Tumor Institute at the Cleveland Clinic Foundation and Principal Investigator on the study presented the data in abstract #1534, titled "Standard Whole Brain Radiation Therapy (WBRT) with supplemental oxygen (O2), with or without RSR13 (efaproxiral) in patients with brain metastases: Results of the randomized REACH (RT-009) study." In the overall study population of 538 patients with brain metastases originating from select solid tumors, the RSR13 (efaproxiral) arm demonstrated a 17.6 percent improvement in MST compared with the control group (5.26 mo vs. 4.47 mo; p=0.17). In a Cox multiple regression model patients in the RSR13 (efaproxiral) arm had a 22 percent reduction in the risk of death (Hazard Ratio 0.78 [95% CI 0.64, 0.94], p=0.010) compared to control. A pre-specified subset of patients with brain metastases originating from breast cancer or non-small cell lung cancer (NSCLC) (n=414) receiving RSR13 (efaproxiral) demonstrated a 32.4 percent increase in MST compared with the control group (5.91 mo vs. 4.47 mo; p=0.12). In patients with brain metastases originating from breast cancer (n=115) the MST almost doubled in those patients who received RSR13 (efaproxiral) and was statistically significant compared with the control group (8.67 vs. 4.57 mo; p=0.006). Patients with brain metastases originating from breast cancer represent a subset of patients that was not prospectively defined as an intent-to-treat subgroup in the Phase 3 trial. The abstract may be accessed online at http://www.asco.org/ at the conclusion of the meeting. Dr. Suh commented, "These results are very promising and the survival benefit and improved quality of life observed in this trial in patients with brain metastases from breast cancer are especially encouraging. This patient population needs new therapeutic approaches that positively impact survival and quality of life. These data support the continued evaluation of RSR13 (efaproxiral) in patients with brain metastases originating from breast cancer and, potentially, from other solid tumors as well." Other key findings from the study include: -- The percentage of breast cancer patients with stable or improved Karnofsky Performance Status, a measure of quality of life, at 3 months was significantly higher in the RSR13 (efaproxiral) arm compared with controls (35 percent vs. 18 percent, p=0.001). -- Only 7 percent of patients treated with RSR13 (efaproxiral) experienced a serious adverse event (SAE) related to the drug. The most common SAE was hypoxia (3.4 percent), which was dose-dependent and effectively managed with supplemental oxygen. "We are currently conducting the ENRICH (ENhancing Whole Brain Radiation Therapy In Patients with Breast Cancer and Hypoxic Brain Metastases) trial, which is designed to confirm the promising results observed in the REACH trial in patients with brain metastases originating from breast cancer," said Michael E. Hart, President and CEO of Allos Therapeutics, Inc. "We recognize that this patient population has significant unmet medical need and we believe that RSR13 (efaproxiral) may provide these patients with a new approach to treating their disease." Allos recently launched a multi-center Phase 3 randomized open label trial of RSR13 (efaproxiral) as an adjunct to whole brain radiation therapy for the treatment of brain metastases from breast cancer. The trial, called ENRICH (ENhancing Whole Brain Radiation Therapy In Patients with Breast Cancer and Hypoxic Brain Metastases), will seek to enroll approximately 360 patients at up to 50 cancer centers across North America. About RSR13 (efaproxiral) RSR13 (efaproxiral) is the first synthetic small molecule designed to "sensitize" hypoxic (oxygen-deprived) areas of tumors prior to radiation therapy by facilitating the release of oxygen from hemoglobin, the oxygen- carrying protein contained within red blood cells, and increasing the level of oxygen in tumors. The presence of oxygen in tumors is an essential element for the effectiveness of radiation therapy in the treatment of cancer. By increasing tumor oxygenation at the time of treatment, RSR13 (efaproxiral) has the potential to enhance the efficacy of standard radiation therapy. Unlike chemotherapeutics or other radiation sensitizers, RSR13 (efaproxiral) does not have to cross the blood brain barrier or enter the tumor to be effective. About Allos Therapeutics, Inc. Allos Therapeutics, Inc. is a biopharmaceutical company focused on developing and commercializing innovative drugs for improving cancer treatments. The company's lead clinical candidate, RSR13 (efaproxiral), is a synthetic small molecule that has the potential to sensitize hypoxic (oxygen deprived) tumor tissues and enhance the efficacy of standard radiation therapy. In addition, Allos is developing PDX, an injectable small molecule chemotherapeutic agent that has an enhanced potency and toxicity profile relative to methotrexate and other dihydrofolate reductase, or DHFR, inhibitors. For more information, please visit the company's web site at: http://www.allos.com/. This announcement contains forward-looking statements that involve risks and uncertainties. Future events may differ materially from those discussed herein due to a number of factors, including, but not limited to, risks and uncertainties related to the company's ability to successfully complete the ENRICH trial on schedule and in accordance with regulatory requirements, and the company's ability to adequately demonstrate the safety and efficacy of RSR13 for the treatment of brain metastases from breast cancer or any other type of cancer, as well as other risks and uncertainties detailed from time to time in the company's SEC filings, including its Annual Report on Form 10-K for the year ended December 31, 2003, as amended. Results from earlier clinical trials are not necessarily predictive of future clinical results. 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 assumes no responsibility to update such statements. DATASOURCE: Allos Therapeutics, Inc. CONTACT: Fern Lazar of Lazar Partners Limited, +1-212-867-1762, , for Allos Therapeutics, Inc. Web site: http://www.allos.com/ http://www.asco.org/

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