Actinium Advances Actimab-A With Manufacturing Expansion

New York, United States, August 14, 2026

Actimab-A Patent Portfolio Continues to Expand

Actinium has continued to strengthen the intellectual property portfolio surrounding Actimab-A, covering its manufacture and therapeutic use in multiple cancer indications. Over the past year, the company has added patents and advanced applications covering Actimab-A in hematologic malignancies and solid tumors. Two newly issued U.S. patents expand the potential application of Actimab-A against myeloid-derived suppressor cells (MDSCs) in solid tumors. U.S. Patent 12,491,274 covers treatment of sarcoma and expires in 2043, while U.S. Patent 12,539,340 covers solid tumors generally, including use alone or in combination with checkpoint therapy. According to Actinium, these patents extend its anti-CD33 therapeutic strategy beyond hematologic cancers by targeting immunosuppressive cells within the tumor microenvironment rather than directly targeting tumor cells. The company also reported additional patent activity related to low-peripheral-blast AML, Actimab-A combinations with the BCL-2 inhibitor venetoclax, and Actimab-A used with CLAG-M chemotherapy for AML. Applications remain pending in several international jurisdictions, supporting Actinium’s efforts to establish broader intellectual property protection for its targeted radiotherapy platform.

Manufacturing Capacity Expands Ahead of Clinical Milestones

Alongside its intellectual property developments, Actinium has amended its Investigational New Drug (IND) application to add an additional manufacturer for Actimab-A. The new manufacturing source is expected to supply studies conducted under the company’s Cooperative Research and Development Agreement (CRADA) with the National Cancer Institute (NCI) as well as additional company-sponsored clinical studies. The expansion is intended to increase manufacturing capacity and supply flexibility as Actimab-A moves into a broader set of studies involving both hematologic malignancies and solid tumors. Reliable manufacturing capacity is particularly important for radiopharmaceutical development because clinical programs require consistent production and supply of complex radioactive therapeutic products. Actinium expects clinical milestones associated with its Actimab-A program beginning in the fourth quarter of 2026 and continuing into 2027. The company is developing Actimab-A as a targeted radiotherapy designed to deliver therapeutic radiation through an antibody-based targeting mechanism, with the goal of improving cancer treatment while limiting exposure to healthy tissue.The program includes ongoing development in AML and MDS, as well as research evaluating Actimab-A’s potential in solid tumors through MDSC targeting. Actinium also reported that Actimab-A has demonstrated improved survival in relapsed or refractory AML when used with CLAG-M and is advancing toward a planned Phase 2/3 clinical trial.

Targeted Radiotherapy Pipeline Supports Oncology Strategy

Actinium’s broader pipeline reflects its focus on targeted radiopharmaceuticals and radioconjugates for cancer. In addition to Actimab-A, the company is developing ATNM-400 for solid tumors and targeted conditioning agents including Iomab-B for bone marrow transplantation and Iomab-ACT for conditioning associated with cell and gene therapy. The company said its pipeline is supported by approximately 250 patents and patent applications, including intellectual property related to cyclotron-based production of Actinium-225 (Ac-225). Ac-225 is a radioactive isotope used in targeted alpha-particle therapy approaches.

The combination of clinical development, expanded manufacturing capacity and intellectual property protection provides Actinium with infrastructure to advance its targeted radiotherapy programs. The additional manufacturer is expected to provide greater supply flexibility as clinical activity increases, while newly issued patents may broaden potential applications for Actimab-A. Actinium also announced that NYSE Regulation accepted its compliance plan and granted the company a plan period through November 27, 2027, during which its common stock will continue trading on NYSE American under the symbol ATNM, subject to applicable requirements. While the listing update is primarily corporate in nature, the central scientific and pharmaceutical development remains the expansion of the Actimab-A manufacturing and clinical development program. The latest announcement therefore represents a significant development for Actinium’s targeted radiotherapy platform, particularly as the company prepares for upcoming clinical milestones across hematologic and solid tumor cancers.

Source: Actinium Pharmaceuticals press relese