ALTH Allos Therapeutics, Inc. (MM)

Data Presented at ASCO Demonstrate That Red Blood Cell Levels of Allos Therapeutics' RSR13 Correlate With Treatment Effect in Patients With Brain Metastases NEW ORLEANS, June 7 /PRNewswire-FirstCall/ -- Allos Therapeutics, Inc. (NASDAQ:ALTH) announced the presentation of new pharmacokinetic (PK) data from its Phase 3 clinical trial of the investigational radiation sensitizer RSR13 (efaproxiral) in patients with brain metastases. Preliminary data from the Phase 3 study, called REACH, were first announced in April 2003. A retrospective analysis of the results from the study indicate that the concentration of RSR13 (efaproxiral) in the red blood cells of patients with brain metastases treated with whole brain radiation therapy (WBRT) clearly correlated with the improvement in survival observed in these patients. Patients who achieved optimal RSR13 (efaproxiral) levels had better clinical outcomes than patients who did not. Edward G. Shaw, MD, Professor and Chairman, Department of Radiation Oncology, Wake Forest University School of Medicine, presented the findings in a poster session yesterday at the 40th Annual Meeting of the American Society of Clinical Oncology (ASCO). In abstract #1561, titled "Pharmacokinetics (PK) of RSR13 (efaproxiral) predict survival in patients with brain metastases randomized to receive whole brain radiation therapy (WBRT) with or without RSR13 (REACH RT-009)," Dr. Shaw and colleagues evaluated the impact of RSR13 (efaproxiral) dosing and the concentration of RSR13 (efaproxiral) in red blood cells on median survival time. Blood samples were taken for PK analysis on Day 1 of RSR13 (efaproxiral) administration and at least once during the second week of therapy. Successful dosing was defined as a PK greater than 483 ug/ml based on the ability of these levels to induce the desired pharmacodynamic effect. Results of the analysis indicated that patients who received at least 7 successful doses of RSR13 (efaproxiral) experienced a statistically significant improvement in median survival time compared with patients who received 7 doses of WBRT alone. The largest improvement was observed in patients whose brain metastases originated from breast cancer. The abstract may be accessed online at http://www.asco.org/ at the conclusion of the meeting. "These analyses reveal that patients in this study who received optimal RSR13 (efaproxiral) dosing experienced a statistically significant increase in median survival time," said Dr. Shaw, a co-Principal Investigator on the study. "These data support the potential utility of RSR13 (efaproxiral) as adjunct therapy to whole brain radiation and supplemental oxygen for the treatment of brain metastases. Additionally, the incorporation of PK analysis into treatment regimens that include RSR13 (efaproxiral) may help to optimize RSR13 (efaproxiral) dosing and maximize its radiosensitizing effects and benefits to patients. We believe that this may translate into improved outcomes for patients with brain metastases, who have few treatment options that improve survival." "These PK analyses enhance our understanding of the clinical outcomes observed in this Phase 3 trial," said Michael E. Hart, President and CEO of Allos Therapeutics, Inc. The REACH study was a randomized, open label Phase 3 clinical trial designed to demonstrate that RSR13 is safe and effective for treating patients with brain metastases resulting from a variety of solid tumors. The study enrolled 538 patients and compared the safety and efficacy of RSR13 plus WBRT and supplemental oxygen (271 patients) versus WBRT and supplemental oxygen (267 patients) in patients with brain metastases. Of the 271 patients in the treatment arm, 188 patients had at least 2 PK determinations, 64 had 1 PK determination and 19 had no PK evaluation. Patients were assigned to 1 of 5 groups based on the number of WBRT doses and the number of RSR13 (efaproxiral) doses received. The WBRT control arm comprised two of these groups: patients receiving fewer than 7 doses of WBRT and patients receiving 7 or more doses of WBRT. The treatment arm comprised three groups: Patients receiving fewer than 7 doses of RSR13 (efaproxiral); patients receiving at least 7 doses but who had fewer than 7 successful doses; and patients receiving at least seven successful doses. The primary endpoint of the trial was survival. 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 usefulness of PK analyses in optimizing RSR13 dosing levels, and company's ability to adequately demonstrate the safety and efficacy of RSR13 for the treatment of brain metastases 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. 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.asco.org/ Web site: http://www.allos.com/

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