Actinium Pharmaceuticals Shares Insights on Iomab-ACT at ASH 2026

Actinium Pharmaceuticals, Inc. has unveiled three abstracts pertaining to the development of Iomab-ACT, a CD45-targeted radioimmunotherapy designed as a conditioning regimen for both CAR T-cell therapy and allogeneic stem cell transplantation. These findings will be presented at the 68th American Society of Hematology (ASH) Annual Meeting and Exposition.

The abstracts provide insights from several clinical studies focusing on Iomab-ACT. One study from Memorial Sloan Kettering Cancer Center reports on the application of Iomab-ACT prior to CD19-directed CAR T-cell therapy, assessing its impact on CAR T-cell expansion, immune cell depletion, and treatment-related toxicities. Also highlighted is the preliminary analysis of Iomab-ACT's role in conditioning regimens for patients with severe sickle cell disease, aiming to enable donor engraftment without the use of conventional chemotherapy.

A Phase 1b/2 trial is also presented, which examines the use of Iomab-ACT before standard commercial CD19-directed CAR T-cell therapy. Overall, these studies underscore the potential of Iomab-ACT in optimizing patient preparedness for cellular therapies while minimizing reliance on traditional chemotherapy.

Sandesh Seth, Chairman and CEO of Actinium, emphasized the significance of these ASH presentations in advancing the understanding of Iomab-ACT as a novel conditioning agent designed to improve outcomes for patients undergoing cellular and gene therapies. He noted the encouraging initial clinical experiences with investigational CAR T-cell therapies and expressed enthusiasm about further evaluating Iomab-ACT alongside commercial CAR T-cell therapies. The clinical findings in severe sickle cell disease suggest its utility may extend beyond oncology.

Iomab-ACT ASH 2026 Presentation Details

1. Abstract Title: First Preliminary Results of Anti-CD45 ¹³¹I-Radioimmunotherapy (Iomab-ACT) as Nonmyeloablative Conditioning for HLA-Matched Sibling Allogeneic Stem Cell Transplantation in Severe Sickle Cell Disease (SCD)
   Session Title: 721. Allogeneic Transplantation: Conditioning Regimens, Engraftment, and Acute Toxicities: Poster II
   Presenting Author: Markus Y. Mapara, Columbia University Irving Medical Center
   Location: Ernest N. Morial Convention Center, Hall F
   Date: Sunday, December 13, 2026
   Time: 6:00 PM – 8:00 PM
2. Abstract Title: Low-dose ¹³¹I apamistamab prior to adoptive cellular therapy (Iomab-ACT) for relapsed/refractory DLBCL and B-cell ALL serves as a promising means of lymphodepletion while preventing severe CRS and neurologic toxicity
   Lead Author: Mark Geyer, Memorial Sloan Kettering Cancer Center
3. Abstract Title: Precision CD45-directed ¹³¹I radioimmunotherapy immune conditioning before CD19-directed CAR T-cell therapy for lymphoid malignancies: the phase 1b/2 IOMAB-ACT trial
   Lead Author: Farrukh T. Awan, UT Southwestern Medical Center

Iomab-ACT is currently being investigated as an innovative strategy for conditioning prior to cellular therapies by delivering targeted radiation to CD45-expressing cells, thereby preparing the immune environment for subsequent treatments. Its safety and efficacy are still under examination.