Allos Announces Survival Benefits of Efaproxyn™ in Phase III Study

Allos Therapeutics, Inc. (Nasdaq: ALTH) announced the results from its Phase III study of Efaproxyn™ in patients with brain metastases. Results of the study, which were reported in the Journal of Clinical Oncology, suggest that the addition of Efaproxyn™ to whole brain radiation therapy may improve survival and response rates in patients with brain metastases, particularly those from breast cancer.

To further confirm the survival benefit observed in the breast cancer subgroup in the trial, in February 2004, the Company initiated a Phase III, randomized, open-label, multi-center trial designed to compare the effect of whole brain radiation therapy with supplemental oxygen with or without Efaproxyn™ in women with brain metastases from breast cancer. Allos currently expects to complete patient enrollment in the trial during the second half of 2006 and report preliminary results approximately six months thereafter.

Efaproxyn™ is the first synthetic small molecule designed to sensitize hypoxic, or oxygen-deprived, areas of tumors during 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. By increasing tumor oxygenation, Allos believes that Efaproxyn™ has the potential to enhance the efficacy of standard radiation therapy.