By John Vandermosten, CFA
NYSE: ATNM
READ THE FULL ATNM RESEARCH REPORT
We are initiating coverage of Actinium Pharmaceuticals, Inc. (NYSE: ATNM) and assign a valuation of $4.00 per share. This valuation is based on our estimates for successful development, approval, and commercialization of ATNM-400 in solid tumors, Actimab-A, Iomab-ACT, and Iomab-B in acute myeloid leukemia (AML), solid tumors, and conditioning regimens in the United States and developed world. Actinium is a clinical-stage biopharmaceutical company developing radiopharmaceuticals for both therapeutic and conditioning applications in multiple areas.
Actinium is developing a pipeline of therapeutic and conditioning assets pursuing important indications in oncology and gene therapy. This includes targets in solid tumors for its preclinical ATNM-400 program and cell surface protein targets CD33, CD45, and CD38 in other areas. In alignment with its name, Actinium’s warhead portfolio includes Ac-225; however, it employs other radioisotopes, including Iodine-131 for its conditioning candidates and Lutetium-177 in preclinical work. Combination therapies are another area of interest for Actinium, where it is working with checkpoint, FLT3, and menin inhibitors.
Actinium’s primary focus is on ATNM-400, which is being developed for an undisclosed target expressed in prostate, lung and breast cancer. The radioconjugate’s target is prolific in these tumors and is scarce on non-cancerous cells compared with the prevalence of prostate-specific membrane antigen (PSMA). Actinium’s recent presentations suggest that ATNM-400 should be more effective in micrometastases compared with alternatives. The company has presented posters at leading oncology conferences characterizing the candidate’s activity in several solid tumor settings. It is positioning ATNM-400 to be the next generation of therapy in prostate cancer, leveraging the effective emissions profile of Ac-225. Actinium is also developing other preclinical assets in relapsed/refractory (r/r) AML using its Actimab-A combinations and theranostic applications in solid tumors.
Actinium’s most advanced candidate is Iomab-B, which has been evaluated in a Phase III trial. It is a CD45-directed monoclonal antibody called apamistamab conjugated to Iodine-131. The candidate was evaluated as a targeted conditioning agent in hematopoietic stem cell transplantation (HSCT) for older patients with r/r AML. While the Phase III trial results were positive, the FDA changed its requirements for accepting the biologic license application (BLA) prior to evaluation and did not accept it. The program is on hold pending partner identification. A derivative of Iomab-B called Iomab-ACT, which has the same construct, is designed to deliver nonmyeloablative or lymphodepleting conditioning prior to CAR‑T or gene therapy. These indications are in early-stage clinical trials.
Actimab-A is Actinium’s hematology franchise and is being investigated in multiple AML indications. The company has advanced the Actimab-A candidates in clinical trials and is seeking to collaborate. These programs are supported by a Cooperative Research and Development Agreement (CRADA) with the National Cancer Institute, which enables cost-effective clinical development with commercial rights retained by Actinium. Actimab-A is a targeted α‑particle radiotherapeutic composed of a humanized anti-CD33 monoclonal antibody, called lintuzumab, conjugated to Actinium‑225. The most clinically advanced Actimab-A program is pursuing r/r AML with a combination approach including CLAG-M and is preparing for a Phase II/III study. The radiotherapeutic is also being evaluated in combination therapy with venetoclax and a menin inhibitor among other agents. The other important Actimab-A program targets myeloid-derived suppressor cells (MDSCs) in combination with checkpoint inhibitors. Eradicating CD33+ MDSCs may overcome resistance to immunotherapy and help checkpoint inhibitors work better.
Ac-225 is more difficult to source compared with other isotopes, such as industry workhorses like Lutetium-177. Nevertheless, Ac-225 is an attractive alternative that combines high-energy α-particles with an optimal half-life to treat resistant cancers. Furthermore, Actinium is developing a new process to more efficiently manufacture Ac-225, which can reduce its cost by a factor of 10 or more. The related facility should be operational by 2H:26. Ac-225’s α particles emit substantial energy over a short distance, generating lethal double-strand breaks in DNA compared with β-emissions that transmit less energy over a wider field. Ac-225’s decay mechanism releases four α particles, delivering a lethal dose to tumor tissue. Ac-225 can be chelated to a targeting vector such as a monoclonal antibody, allowing it to be precisely delivered. Its half-life of ten days balances ease of distribution with patient radiation exposure.
Based on the candidates' status, management intent and capital resources, our valuation captures ATNM-400 in solid tumors, Iomab-ACT, Actimab-A and Iomab-B in AML and conditioning. We expect both Actimab-A and Iomab-B to be advanced with partners, who will carry the programs through regulatory approval and commercialization. In return, Actinium is expected to receive customary upfront payments, milestones and royalties. To simplify, our approach estimates a royalty rate that will represent all components of value received.
Radiopharmaceuticals are essential tools for diagnostic, therapeutic, and conditioning applications across multiple disease states. In oncology, these agents enable early cancer detection, tumor localization, and precise metastasis staging. Beyond diagnostics and direct cancer therapy, radiopharmaceuticals play a critical role in targeted conditioning regimens, such as myeloablation and lymphodepletion, to safely prepare patients for bone marrow transplants and other cellular therapies.
Key reasons to own Actinium Pharmaceuticals shares:
- Diverse radiopharmaceutical pipeline with multiple indications under development
- ATNM-400 for multiple solid tumor targets (prostate, lung & breast)
- Actimab-A to resensitize the immune system by depleting MDSCs in solid tumors
- Iomab-ACT conditioning directed against CD45 for gene therapy and CAR-T
- Achieves selective lymphodepletion at lower doses
- Preserves hematopoietic recovery
- Late stage partnering opportunities
- Actimab-A + CLAG-M in AML
- Iomab-B in AML directed against CD45 for bone marrow transplant conditioning
- Offers improved access and outcomes
- Reduced toxicity compared with standard-of-care
- Pipeline of in-development clinical assets
- Combination therapies with PD-1 inhibitors
- Undisclosed targets and theranostics
- $36 million cash position supporting operations into 2028
- No debt, material warrants or preferred issues on the balance sheet
The initiation report introduces radiopharmaceuticals to investors, defining the industry and discussing the different types of radiation and particles involved. We start with a brief history, then describe the conditioning and therapeutic categories, including details regarding the important subcategories of the therapeutic modality. Radiopharmaceuticals require advanced logistics, management, and care compared to other biopharmaceutical offerings. We describe the framework behind their regulation, transportation, and disposal. The report provides an industry review tracing the recent commercial history of the drug class, including new company formation and merger and acquisition activity.
The next section examines Actinium’s primary end markets. Products and pipeline are next, as we review the firm’s assets. Peers and competitors are reviewed, including a summary of their industry focus. We list historical milestones and background on Actinium, followed by a summary of recent financial performance. Key members of senior management are introduced, and risks related to life sciences companies in general and for Actinium specifically are discussed. The report concludes with valuation work and a presentation of our model’s assumptions. The target price relies on a discounted cash flow (DCF) model that estimates contributions from ATNM-400, Iomab-ACT, Actimab-A and Iomab-B in both the U.S. and developed countries. We initiate on Actinium Pharmaceuticals, Inc. with a valuation of $4.00 per share.
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