Actinium Pharmaceuticals, Inc. announced safety data from its ongoing pivotal Phase 3 SIERRA trial of Iomab-B in patients with relapsed or refractory Acute Myeloid Leukemia (r/r AML) Iomab-B targets CD45, an antigen expressed on leukemia and lymphoma cancer cells and immune cells including bone marrow stem cells but not on cells outside of the blood forming or hematopoietic system. This allows high amounts of radiation to be delivered to the bone marrow via Iomab-B while sparing critical organs. As a result, statistically significant lower rates of sepsis were reported as well as lower rates of febrile neutropenia, mucositis and non-relapse transplant related mortality in patients receiving Iomab-B and bone marrow transplant (BMT) compared to patients that received salvage therapy and a BMT. In addition, patients who crossed over to receive Iomab-B and went to BMT after receiving salvage therapy but not achieving a complete response also had lower rates of sepsis, febrile neutropenia, mucositis and non-relapse transplant related mortality.