Actinium Pharmaceuticals To Present Early Phase 1 Clinical Data For ATNM-400 In Metastatic Prostate Cancer At EANM 2026

• Early clinical data from the Phase 1 theranostic trial support the advancement of ATNM-400 as a non-PSMA targeted alpha therapy for metastatic castration-resistant prostate cancer (mCRPC)
  
  
  
   
• Evaluation of Zirconium-89-labeled ATNM-400 to assess safety, biodistribution, and dosimetry to inform the development of Actinium-225-labeled ATNM-400 as a targeted radiotherapy
  
  
  
   
• ATNM-400 is a first-in-class, non-PSMA targeted radiotherapy being developed to address a broad mCRPC patient population, including PSMA-low and PSMA-negative disease and patients who do not respond to or progress following PSMA-directed therapies

NEW YORK, Oct. 15, 2026 /PRNewswire/ -- Actinium Pharmaceuticals, Inc. (NYSE:ATNM) (Actinium or the Company), a pioneer in differentiated targeted radiotherapies with the potential to transform cancer treatment, today announced that an oral presentation with early results from the first-in-human Phase 1 study of ATNM-400 in metastatic castration-resistant prostate cancer (mCRPC) will be presented at the 39th Annual Congress of the European Association of Nuclear Medicine (EANM), October 17–21, 2026, in Vienna, Austria.

The oral presentation will highlight the ongoing first-in-human Phase 1 dose-escalation study of ATNM-400 in mCRPC. ATNM-400 is a first-in-class Actinium-225 (²²⁵Ac) antibody radioconjugate targeting a non-PSMA antigen implicated in tumor survival and treatment resistance. The study will characterize the safety, biodistribution, and dosimetry of Zirconium-89-labeled ATNM-400. Serial PET imaging will assess its tumor uptake, distribution, and clearance, with dosimetry estimates informing therapeutic ²²⁵Ac-ATNM-400 dosing.