Allos Therapeutics Inc has completed patient enrollment in the pivotal Phase 3 clinical trial of the Company's leading drug candidate, RSR13 (efaproxiral), in patients with brain metastases receiving whole brain radiation therapy.

RSR13, a synthetic allosteric modifier of hemoglobin, is the first investigational drug candidate in a new class of radiation sensitizing agents. In Phase 2 clinical trials, RSR13 has been shown to increase the efficacy of radiation therapy in a variety of cancers, including brain metastases, non-small cell lung cancer and glioblastoma multiforme.

The study was initiated in February 2000, and 538 patients were enrolled at more than 80 leading cancer centers in 11 countries, including the United States, Canada, Europe and Australia. This randomized open-label pivotal Phase 3 study was designed to compare the safety and efficacy of whole brain radiation combined with RSR13 to whole brain radiation alone in patients with brain metastases. The primary endpoint of the trial is a 35% improvement in survival of the RSR13 treatment arm versus the control arm.

Study co-chairpersons are Edward Shaw, Wake Forest University and John Suh, Cleveland Clinic Foundation. The FDA has granted Fast Track Product designation for RSR13 in this indication.

Brain metastases, the most common type of brain cancer, are tumors that have spread to the brain from a malignant tumor in another part of the body. This condition occurs in approximately one out of five cancer patients, most often in patients with non-small cell lung cancer or breast cancer. Standard whole brain radiation is the primary mode of therapy for these patients and it has been shown to prevent or reduce complications and to increase survival.