Benzinga | Mar 11, 2021 07:04AM EST

Actinium To Present On Expansion Af Targeted Conditioning Portfolio At AACR Meeting Apr. 10

NEW YORK, March 11, 2021 /PRNewswire/ -- Actinium Pharmaceuticals, Inc. (NYSE:ATNM) ("Actinium" or the "Company") today announced that preclinical feasibility data supporting an Actinium-225-based CD45-targeted Next-Generation conditioning agent has been accepted for poster presentation at the American Association of Cancer Research (AACR 2021) annual meeting being held virtually April 10th -- 15th, 2021. The data to be presented includes initial dose escalation, safety, tolerability, and conditioning experiments of an Ac-225-based CD45 ARC or antibody radiation conjugate. Dosimetry results with this Ac-225-based alpha emitting ARC showed selective accumulation in immune cell target organs such as bone marrow, spleen, and liver with the potential for lower exposure to non-target tissues from longer path length beta emitter radioisotopes like Iodine-131 and Lutetium-177. The data to be presented demonstrate that conditioning with this Ac-225-based CD45-targeting agent result in depletion of peripheral immune cells and hematopoietic progenitor cells, thereby enabling engraftment of donor cells. A dose dependent response was observed with low doses depleting white blood without effecting hematopoietic progenitor cells, representing a lymphodepletive dose that is relevant for adoptive cell therapies such as CAR-T, while higher doses eliminated peripheral immune cells and hematopoietic progenitor cells, which is applicable to ex vivo gene therapies and BMT or bone marrow transplant.

This program further augments Actinium's targeted conditioning portfolio that is led by Iomab-B, an ARC consisting or the radioisotope Iodine-131 and the CD45 targeting antibody apamistamab. In total, apamistamab has been studied in several hundred patients. Iomab-B is currently being studied in the pivotal Phase 3 SIERRA trial for BMT conditioning in patients with active relapsed or refractory acute myeloid leukemia age 55 and above that is expected to complete enrollment in 2021.

Details of the poster presentation at AACR are as follows:

Dose optimization and radiation dosimetry of CD45-targetingTitle: 225Actinium-armed antibody as a conditioning agent for adoptive cell therapy

Session E-Poster SessionType:

Session ImmunologyCategory:

Session Adoptive Cell TherapyTitle:

Poster 8:30 a.m. ET on Saturday, April 10Release: