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Investigational New Drug Application Filed for Skeletal Targeted Radiotherapy Agent
Researchers at Houston-based MD Anderson Cancer Center have conducted a small investigator-initiated phase I dose-escalation study of STR in patients with stage IV breast cancer involving osseous (bony) metastases. Six patients were administered STR as a single agent, followed by autologous (self-donor) blood stem cell transplantation. Two of the six patients remain alive, without progression of their disease for over five years post-transplant. The median time to disease progression in the other four patients was 220 days (range:92 to 370 days). Disease relapse in these four patients occurred in tissues outside the bone.
"We are encouraged by the results from this first small study of STR in breast cancer patients with osseous metastases," said Richard E. Champlin, MD, Chair of the Department of Blood and Marrow Transplantation at MD Anderson Cancer Center. "Two patients in the study have survived more than five years without disease recurrence, which is rarely achieved with any other therapy. These results suggest that STR may be effective in ablating cancerous lesions in the tissues it specifically targets, the bone and bone marrow."
Dr. Champlin added, "It also should be noted that STR was used as a single agent in this early study, without high-dose chemotherapy as part of the transplant conditioning regimen. Given its favorable acute tolerability profile, STR may represent a more acceptable treatment option for this patient population than the typical, highly toxic chemotherapy regimens used for transplant conditioning."
Jerry McMahon, PhD, Chairman and CEO of NeoRx, commented, "Filing this IND is in keeping with our strategy to broaden the use of STR to treat patients with bone metastases from other major types of cancer. We look forward to working with the FDA to finalize the protocol for a single-agent phase II trial of STR in breast cancer patients with bone metastases, in anticipation of beginning the study in the first half of 2005."
STR, also known as 166Ho-DOTMP, is an innovative cancer therapeutic that delivers radiation directly to cancer cells in the bone and bone marrow, thereby minimizing exposure of normal tissues to radiation. STR is composed of a bone-targeting molecule, DOTMP, in a stable complex with the radionuclide holmium-166. When injected into a patient's bloodstream, STR rapidly binds to bone mineral, delivering a brief, intense dose of radiation to destroy cancer cells in the bone and marrow. STR that does not bind to bone is rapidly eliminated from the body shortly after administration. STR treatment is followed by infusion of a patient's own previously collected blood stem cells to restore bone marrow function. NeoRx currently is conducting a phase III pivotal study of STR in patients with multiple myeloma.
Source: NeoRx Corporation