Study Comparing STR (Skeletal Targeted Radiotherapy) Plus Melphalan to Melphalan Alone, With Stem Cell Transplant in Multiple Myeloma

Study Summary

STR (Skeletal Targeted Radiotherapy, 166Ho-DOTMP) is an investigational radiopharmaceutical that delivers radiation directly to cancer cells in the bone and bone marrow. Conventional methods of delivering radiation therapy, such as total body irradiation, expose non-target tissues to radiation and cause serious side effects. In contrast, STR's targeted approach to delivering radiotherapy concentrates the radiation where it is needed, and minimizes exposure of normal tissues. 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. The high-energy and long path-length of holmium-166 beta particles provide optimal penetration and uniform irradiation of disease sites in the marrow and bone. STR that does not bind to bone is rapidly eliminated through the urinary tract. STR treatment is followed by autologous stem cell transplantation. The short half-life of holmium-166 allows treatment on an out-patient basis, and minimizes the time required between STR administration and transplantation. The phase III study of STR is a multi-center, randomized, controlled study, designed to evaluate the safety and efficacy of STR in patients with primary refractory multiple myeloma. These are patients who have failed to achieve at least a partial response to conventional therapy and have been undergoing treatment for less than 18 months. The trial is expected to enroll approximately 240 evaluable patients, half on the experimental arm and half on the control arm. Patients on the experimental arm will receive STR at a dose of 750 mCi/m2 plus the chemotherapy drug melphalan at 200 mg/m2, followed by autologous stem cell transplantation. Patients on the control arm will receive melphalan only, followed by transplantation. Patients on both study arms will be evaluate

Interventions

• DRUG STR(TM) (Skeletal Targeted Radiotherapy, Holmium-166-DOTMP)