# Actinium Pharmaceuticals

Source: https://nuclide.cc/companies/actinium-pharmaceuticals/  
Nuclide record `actinium-pharmaceuticals` (Company). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

Actinium Pharmaceuticals attaches the alpha-emitting isotope actinium-225 to antibodies to treat acute myeloid leukaemia and, more recently, solid tumours such as prostate and lung cancer. It is a small listed company whose lead programme is approaching new clinical milestones.

## Summary

Actinium Pharmaceuticals, Inc. (NYSE American: ATNM), headquartered in New York, develops targeted radiotherapies based on actinium-225 antibody radioconjugates and holds proprietary Ac-225 manufacturing technology. The lead programme Actimab-A is a CD33-targeting, mutation-agnostic therapy for relapsed or refractory acute myeloid leukaemia, with patents extending to solid tumours via myeloid-derived suppressor cells; the company expects clinical milestones from the fourth quarter of 2026. ATNM-400 is a first-in-class Ac-225 pan-tumour radiotherapy in preclinical development for metastatic castration-resistant prostate cancer, non-small cell lung cancer and breast cancer, with 2026 SNMMI data in androgen receptor inhibitor-resistant prostate models and KRAS and EGFR mutant lung models. Iomab-ACT is a targeted conditioning programme. In 2026 the company received NYSE American listing standards notices and appointed Steffen Heeger as Chief Medical Officer.

## Fields

- Kind: Company
- Last checked: 2026-09-10
- HQ: New York, NY
- Type: radiopharma
- Website: https://www.actiniumpharma.com/
- Ticker: ATNM

## Notes

- Ticker, exchange and HQ confirmed via SEC EDGAR submissions data (CIK 0001388320). Public company; no private rounds listed. Founding year not sourced.

## Sources

- Official website: https://www.actiniumpharma.com/
- August 2026 Actimab-A and listing update: https://ir.actiniumpharma.com/press-releases/detail/525/actinium-pharmaceuticals-announces-actimab-a-intellectual
- Press releases: https://ir.actiniumpharma.com/press-releases

## Connected records

- isotopes: [Actinium-225](https://nuclide.cc/isotopes/ac-225/)
- indications: [Prostate cancer](https://nuclide.cc/indications/prostate/)
- technologies: [Radio-antibody & radio-ADC](https://nuclide.cc/technologies/radioimmunotherapy/), [Targeted alpha therapy](https://nuclide.cc/technologies/targeted-alpha-therapy/)
- drugs: [Iomab-B](https://nuclide.cc/drugs/iomab-b/)
- trials: [Study of Iomab-B vs. Conventional Care in Older Subjects With Active, Relapsed or Refractory Acute Myeloid Leukemia](https://nuclide.cc/trials/nct02665065/)
- bottlenecks: [Actinium-225 supply](https://nuclide.cc/bottlenecks/b-ac225-supply/)
- fronts: [Targeted alpha therapy](https://nuclide.cc/fronts/f-alpha-therapy/)

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