Actinium Pharmaceuticals, Inc. filed an 8-K on November 4, 2026, announcing the release of three abstracts for the 68th American Society of Hematology Annual Meeting covering clinical findings for Iomab-ACT as a conditioning agent before CAR T-cell therapy and allogeneic stem cell transplantation.

Key Highlights

  • Three abstracts released: The abstracts cover a Phase 1b/2 trial, a Memorial Sloan Kettering Cancer Center study, and a severe sickle cell disease conditioning study, all involving Iomab-ACT.
  • Phase 1b/2 trial: Lead author Farrukh T. Awan of UT Southwestern Medical Center is evaluating Iomab-ACT before standard commercial CD19-directed CAR T-cell therapy for lymphoid malignancies.
  • Memorial Sloan Kettering study: Lead author Mark Geyer evaluated low-dose 131I apamistamab (Iomab-ACT) prior to adoptive cellular therapy for relapsed/refractory DLBCL and B-cell ALL, described as "a promising means of lymphodepletion while preventing severe CRS and neurologic toxicity."
  • Sickle cell disease abstract: Presenting author Markus Y. Mapara of Columbia University Irving Medical Center reports first preliminary results of Iomab-ACT as nonmyeloablative conditioning for HLA-matched sibling allogeneic stem cell transplantation in severe sickle cell disease, to be presented December 13, 2026.
  • ASH presentation date: The sickle cell disease poster is scheduled for Sunday, December 13, 2026, from 6:00 PM to 8:00 PM at the Ernest N. Morial Convention Center, Hall F.
  • Investigational status: According to the filing, Iomab-ACT's "safety and efficacy remain under clinical investigation."

Iomab-ACT Clinical Program Highlighted Across Three ASH 2026 Abstracts

Actinium Pharmaceuticals, Inc. (NYSE American:ATNM) disclosed details of three abstracts accepted for the 68th American Society of Hematology Annual Meeting and Exposition, according to the filing. All three abstracts center on Iomab-ACT, the company's investigational CD45-targeted antibody radioconjugate combining apamistamab with iodine-131, which the company is studying as a conditioning approach before cellular therapies.

The filing describes the Memorial Sloan Kettering Cancer Center study, led by Mark Geyer, as examining low-dose 131I apamistamab before adoptive cellular therapy for relapsed/refractory diffuse large B-cell lymphoma and B-cell acute lymphoblastic leukemia. A second abstract, led by Farrukh T. Awan of UT Southwestern Medical Center, covers the Phase 1b/2 IOMAB-ACT trial evaluating precision CD45-directed radioimmunotherapy immune conditioning before CD19-directed CAR T-cell therapy for lymphoid malignancies. The third abstract, to be presented by Markus Y. Mapara of Columbia University Irving Medical Center, reports first preliminary results from use of Iomab-ACT as nonmyeloablative conditioning for HLA-matched sibling allogeneic stem cell transplantation in severe sickle cell disease.

Chairman and CEO Sandesh Seth stated in the filing that "these ASH presentations mark an important step in the development of our Iomab-ACT CD45-targeted radiotherapy conditioning program," and that the company is "excited by the opportunity to evaluate Iomab-ACT with commercial CAR T-cell therapies." The filing notes that Iomab-ACT is designed to "prepare the host immune environment for subsequent cellular therapy" by delivering radiation to CD45-expressing hematopoietic and immune cells, though the filing cautions that safety and efficacy remain under investigation. The press release contains forward-looking statements subject to risks and uncertainties, as described in the company's cautionary language.

What Was Disclosed

Actinium Pharmaceuticals disclosed three abstracts accepted for the ASH 2026 annual meeting, each involving Iomab-ACT as a conditioning agent before CAR T-cell therapy or stem cell transplantation, with one poster presentation scheduled for December 13, 2026.