What Actinium Pharmaceuticals does

Actinium Pharmaceuticals, Inc. is a New York-based, clinical-stage biopharmaceutical company (NYSE American: ATNM) developing targeted alpha-particle radiotherapies that conjugate Actinium-225 (Ac-225) to monoclonal antibodies for the treatment of cancer. Its pipeline comprises three core programs: ATNM-400, a first-in-class Ac-225 antibody radioconjugate aimed at multiple solid tumor indications including metastatic castration-resistant prostate cancer (including PSMA-negative and ARPI-resistant disease), non-small cell lung cancer (EGFR- and KRAS-mutated), and breast cancer (hormone receptor-positive, HER2-positive, and triple-negative); Actimab-A (lintuzumab-Ac225), an Ac-225-labeled anti-CD33 antibody in development for acute myeloid leukemia that demonstrated an 83% overall response rate with 75% MRD-negativity in a Phase 1 relapsed/refractory trial; and Iomab-ACT, a CD45-targeted Ac-225 conditioning agent designed to enable bone marrow transplant and gene-edited cell therapy applications. The company has built a proprietary radiochemistry capability around chelator-to-antibody ratio (CAR) optimization that reduces off-target hepatic and splenic uptake while preserving tumor targeting, and it is protected by approximately 250 issued and pending patents and applications across the United States, Canada, Japan, Europe, and China, with key composition-of-matter and method claims extending to 2038-2039.

The company is pre-commercial with no disclosed product revenue or pricing; its go-to-market model is built around NCI-sponsored clinical trials and development partnerships (e.g., an NCI-led Actimab-A combination study in newly diagnosed AML advancing toward a Phase 2/3 registrational study under FDA alignment). Customer-facing activity is focused on oncology conference presentations, peer-reviewed publications, and investor relations rather than commercial distribution. Financially, the company is loss-making with net losses in five consecutive fiscal years through December 31, 2025, stockholders' equity of approximately $2.3 million versus a $4.0 million NYSE American minimum (triggering a delisting notice in May 2026 with a compliance plan due by June 26, 2026 and a cure deadline of November 27, 2027), a market capitalization of approximately $30.6 million, and a current ratio of 6.2 reflecting a liquid but equity-thin balance sheet.

Name

Actinium Pharmaceuticals

Legal name

Actinium Pharmaceuticals, Inc.

Website

https://actiniumpharmaceuticals.com

Company type

Public

Founded year

2012

Operating status

Operating

Headcount range

11–50 employees

Short description

Actinium Pharmaceuticals is a clinical-stage biopharmaceutical company developing targeted alpha-particle radiotherapies using Actinium-225-conjugated antibodies to treat hematologic malignancies and solid tumors including prostate, lung, and breast cancers.

Ownership category

akta.pro rank

Product category

Targeted Radiopharmaceuticals

NAICS

Biological Product (except Diagnostic) Manufacturing (325414), Pharmaceutical and Medicine Manufacturing (3254), Research and Development in Biotechnology (except Nanobiotechnology) (541714)

SIC

Biological Products, (No Disgnostic Substances) (2836), Pharmaceutical Preparations (2834)

akta.pro primary industry

Therapeutic Radiopharmaceuticals (Radioligand/Targeted Radionuclide Therapy) (HLAIAGAB)

akta.pro secondary industries

Antibody-Drug Conjugates (ADCs) & Antibody Conjugates (HLAAAAAE), Theranostic Radiopharmaceutical Platforms (Paired Dx/Tx) (HLAIAGAC)

Keywords

• Targeted alpha therapy
• Antibody radioconjugates
• Radiopharmaceutical drug development
• Cancer radiotherapy pipeline
• Clinical stage biopharmaceuticals

Headquarters

HQ city

New York

HQ country

United States

HQ region

North America

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Operations, Marketing or Sales, Others

Distribution channels1 record

Marketing channels3 records

Core offering

Actinium Pharmaceuticals develops targeted alpha-particle radiotherapies using Actinium-225 (Ac-225) conjugated to antibodies to treat cancer. Its pipeline includes ATNM-400 for solid tumors (prostate, lung, breast), Actimab-A for acute myeloid leukemia, and Iomab-ACT for conditioning prior to gene-edited cell therapies. The company leverages proprietary radiochemistry including chelator-to-antibody ratio (CAR) optimization to improve therapeutic index. All assets are currently in preclinical or early clinical development with no commercialized products.

Product overview

Actinium Pharmaceuticals is a clinical-stage biopharmaceutical company developing targeted radiotherapies using Actinium-225 (Ac-225) alpha-particle radiation. The company's pipeline consists of three key programs: ATNM-400, a first-in-class Ac-225 antibody radioconjugate for solid tumors including prostate, lung, and breast cancers; Actimab-A (lintuzumab-Ac225), an Ac-225 labeled antibody for acute myeloid leukemia; and Iomab-ACT, a CD45 conditioning agent for gene-edited cell-based therapies. The company leverages proprietary radiochemistry capabilities including chelator-to-antibody ratio (CAR) optimization to improve therapeutic index across its radiopharmaceutical programs.

Differentiator

Problem solved

Functional benefit

Products and services

• ATNM-400 First-in-class Actinium-225 antibody radioconjugate for solid tumors; demonstrates efficacy across prostate cancer (PSMA-high, PSMA-low, and PSMA-negative; ARPI-resistant), non-small cell lung cancer (EGFR-mutant and KRAS-mutated), and breast cancer (hormone receptor-positive, HER2-positive, and triple-negative) preclinical models, outperforming approved therapies including enzalutamide, apalutamide, darolutamide, osimertinib, trastuzumab deruxtecan, and 177Lu-PSMA-617 in preclinical studies.
• Actimab-A (lintuzumab-Ac225) Actinium-225 labeled antibody therapy for acute myeloid leukemia (AML); demonstrates mutation-agnostic anti-leukemic activity via transcriptional reprogramming; Phase 1 trial achieved 83% overall response rate with 75% MRD-negativity in relapsed/refractory AML in combination with CLAG-M chemotherapy; being advanced into a Phase 2/3 registrational study with FDA alignment and is the subject of an NCI-sponsored combination trial with venetoclax and ASTX-727 in newly diagnosed AML.
• Iomab-ACT CD45-targeted Actinium-225 conditioning agent for gene-edited cell-based therapies; provides targeted bone marrow conditioning prior to gene therapy procedures and bone marrow transplant; patent term extends to October 2038 under Canadian patent protection.
• 225Ac Radioconjugate Platform Proprietary Actinium-225 (Ac-225) alpha-particle radiochemistry platform underpinning the company's radiopharmaceutical pipeline; incorporates chelator-to-antibody ratio (CAR) optimization technology that improves tumor targeting, reduces off-target uptake in liver and spleen, and supports an extended therapeutic window across the pipeline assets.

Quantifiable outcome

• 94% tumor growth inhibition in ARPI-resistant prostate cancer models vs 32% for apalutamide and 5% for darolutamide
• +3 more outcomes

Segments4 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

Two partnerships are on record, tiered minor and core.

• Full-Life TechnologiesminorStrategic or Co-development Partner · 1 June 2026Dr. Steffen Heeger, newly appointed CMO of Actinium Pharmaceuticals, previously served as CMO of Full-Life Technologies where he advanced anti-PSMA radioconjugate programs into clinical development within two years, securing IND clearance and fast-track designation.
• National Cancer Institute (NCI)coreStrategic or Co-development Partner · 22 April 2026NCI-sponsored clinical trial combining Actimab-A with venetoclax and ASTX-727 for newly diagnosed AML patients. NCI collaboration advancing Actimab-A toward a Phase 2/3 registrational study for relapsed/refractory AML under FDA alignment.

Scale indicators7 records

Recent moves6 records

Expansion highlights6 records

Broad incumbents

• Novartis: Owns Pluvicto (177Lu-PSMA-617), the only commercially approved PSMA-directed radioligand therapy. Comparable because it operates in the same targeted radiotherapy oncology space Actinium targets with its Ac-225 platform, though Novartis is a diversified large pharma and Pluvicto targets the PSMA-positive patient population that ATNM-400 is designed to complement or bypass.
• Bayer: Markets Xofigo (223Ra-dichloride), the first commercially approved alpha-emitting radiopharmaceutical for prostate cancer bone metastases. Comparable as a large pharma with a commercial alpha-emitter franchise that establishes the regulatory and commercial template Actinium would need to follow.
• Eli Lilly (POINT Biopharma): Acquired POINT Biopharma in 2023 to gain a PSMA-targeted radioligand therapy (POINT's PNT2002/177Lu-PSMA-I&T) plus a manufacturing infrastructure footprint. Comparable because it is now a direct competitor in PSMA radioligand therapy with the resources to scale that Actinium lacks.
• AstraZeneca (Fusion Pharmaceuticals): Acquired Fusion Pharmaceuticals in 2024 specifically for its targeted alpha therapy (Ac-225-based) platform — directly overlapping with Actinium's core technology. Comparable because Fusion is the closest direct competitor in Ac-225 radiochemistry and is now backed by big-pharma resources.
• Bristol Myers Squibb (RayzeBio): Acquired RayzeBio in 2024 for its actinium-225-based targeted radiopharmaceutical pipeline. Comparable as another big-pharma entrant in the Ac-225 space, validating the platform thesis while raising the competitive bar through resources and pipeline breadth.

Direct peers

• Lantheus Holdings: Radiopharmaceutical company with commercial PSMA imaging agents (PYLARIFY) and an expanding radiotherapeutic pipeline. Comparable as a US-listed, focused radiopharma that serves the same prostate cancer imaging/treatment workflow where Actinium's ATNM-400 aims to treat post-imaging.
• Telix Pharmaceuticals: Commercial-stage radiopharma with Illuccix (PSMA imaging) and an early therapeutic pipeline including TLX591 (177Lu-PSMA antibody). Comparable as a clinical-to-commercial radiopharma operating in the same PSMA-prostate cancer category and pursuing adjacent radioligand therapy development.

Emerging players

• Cellectar Biosciences: Clinical-stage company developing phospholipid drug conjugate-targeted radiopharmaceuticals (including Iopofosine I-131) for hematologic and solid tumors. Comparable as a small-cap US radiopharma with similar clinical-stage scale, capital-constraints profile, and reliance on partnership or M&A to advance.
• Molecular Partners: Clinical-stage biotech developing DARPin-based targeted radioligand therapies, including programs against HER2 and other oncology targets. Comparable as a small-cap company engineering alternative scaffold (DARPin vs. antibody) radioconjugates that could compete with Actinium's antibody-Ac-225 constructs in similar tumor indications.

Others

• ITM Isotope Technologies Munich: Specializes in medical radioisotope manufacturing and radiopharmaceutical development, including targeted radionuclide therapies using Lu-177 and other emitters. Comparable as a supplier/infrastructure participant in the same targeted radionuclide therapy supply chain that Actinium depends on for Ac-225 production and chelation chemistry.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

• Xx.com/ActiniumPharma
• Facebookfacebook.com/actiniumpharma
• LinkedInlinkedin.com/company/actinium-pharmaceuticals-inc-

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Funding overview

Funding rounds8 records

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Actinium Pharmaceuticals