Actinium Pharmaceuticals (ATNM) shares are soaring in pre-market trading today after the company announced that the pivotal Phase 3 clinical trial, SIERRA, for lead product candidate Iomab-B has been initiated. Iomab-B is intended to be an induction and conditioning agent used to prepare patients with relapsed or refractory acute myeloid leukemia (AML) who are over the age of 55 for a hematopoietic stem cell transplant (HSCT), commonly referred to as bone marrow transplant (BMT). There are currently no effective treatments for this patient population.