 NEW YORK, Sept. 15, 2021 PRNewswire -- Actinium Pharmaceuticals, Inc. NYSE AMERICAN: ATNM Actinium or the Company today announced that it has completed enrollment of the pivotal Phase 3 SIERRA trial for Iomab-B, an Antibody Radiation Conjugate ARC comprised of apamistamab, a CD45 targeting antibody, and the radioisotope iodine-131. 