Actinium Pharmaceuticals, Inc. announced that the University of Texas Southwestern Medical Center (UT Southwestern) will lead a clinical trial studying Actinium's Iomab-ACT, a targeted radiotherapy conditioning agent prior to patients receiving an FDA approved commercial CAR T-cell therapy. UT Southwestern will start recruiting patients following FDA's review and clearance of the study. CAR T-cell therapy utilizes patients' own immune cells called T-cells, which are engineered to include a chimeric antigen receptor and then reinfused into the patient to recognize and destroy cancer cells.

Currently, there are six CAR-T therapies approved to treat patients with leukemias, lymphomas and multiple myeloma that collectively reached sales in 2023 exceeding $3.5 billion. Actinium developed Iomab-ACT with the goal of replacing the chemotherapy conditioning regimens currently used prior to cell and gene therapies. Early clinical data with Iomab-ACT conditioning prior to CAR-T demonstrates its ability to produce targeted lymphodepletion along with negligible incidences of immune effector cell-associated neurotoxicity syndrome (ICANS) or cytokine release syndrome (CRS), which are the major toxicities observed with the current chemotherapy based conditioning regimens, which are suboptimal and can limit patients from CAR-T access and may result in poor outcomes.

Ongoing Iomab-ACT Phase 1 CAR-T Conditioning Results: Actinium presented results from its ongoing phase 1 trial using Iomab-ACT as conditioning prior to CD19 CAR-T therapy for patients with relapsed or refractory B-cell Acute Lymphoblastic Leukemia (B-ALL) or Diffuse Large B-cell Lymphoma (DLBCL) at the Tandem Meetings I Transplantation & Cellular Therapy Meetings of ASTCT and CIBMTR the combined annual meetings of the American Society for Transplantation and Cellular Therapy (ASTCT) and the Center for International Blood & Marrow Transplant Research (CIBMTR) in February 2024. Importantly, no patients (0/4) developed immune effector cell-associated neurotoxicity syndrome (ICANS) of any grade, a major safety measure of the study, as ICANS is observed in 25% or more of pts w/R/R B-ALL and DLBCL treated with various CAR T-cell products and minimal CRS. Iomab-ACT demonstrated transient depletion of peripheral blood lymphocytes and monocytes.

Persistence of CAR T-cells up to 8 weeks and minimal non-hematologic toxicities have been observed to date. Targeted Radiotherapy Conditioning Opportunity: The opportunity exists for better conditioning in other areas of cellular therapy, such as CAR-T as well as gene therapies. The pipeline of CAR-T and gene therapies has rapidly expanded, with the addressable patient population expected to nearly double and reach approximately 93,000 patients in the U.S. by 2030 based on the current pipeline of cellular therapies.

The CAR-T market size in terms of revenue is estimated to grow at a CAGR of approximately 11% over the next 5 plus years. Currently, there are six CAR T-cell therapies approved by the FDA that are used to treat patients with lymphomas, leukemia, and multiple myeloma, which collectively had total sales of over $3.5 billion in 2023. The addressable market for Iomab-ACT is in line with the patient population for cell and gene therapies as all patients receive conditioning of some type prior to these treatments.

The company will continue to develop Iomab-ACT, its next-generation conditioning program for rapidly growing cell and gene therapies based on early promising results, ultimately with the value proposition of improving overall access and outcomes for patients who need cellular or gene therapies. A potential blockbuster revenue opportunity exists for Iomab-ACT assuming it can provide one or more clinical benefits related to lower CRS, less ICANS, longer duration of response or a higher overall success rate of cellular therapy due to benefits of targeted conditioning.