Actinium Pharma Reports Additional Preclinical Data Supporting ATNM-400 Radiotherapy Prostate Cancer Candidate At Annual TRP Summit

-     ATNM-400 demonstrates robust efficacy in prostate cancer tumor models with acquired resistance to Pluvicto® and enzalutamide, follow-up continues

-     ATNM-400 significantly improved survival compared to the approved prostate cancer treatment Pluvicto®, the first blockbuster radiotherapy

-     In combination with enzalutamide, an approved ARPI therapy, ATNM-400 produced enhanced efficacy with 40% of prostate cancer tumor-bearing animals achieving complete cures

NEW YORK, July 31, 2025 /PRNewswire/ -- Actinium Pharmaceuticals, Inc. (NYSE:ATNM) (Actinium or the Company), a pioneer in the development of targeted radiotherapies, today reported additional preclinical data supporting its ATNM-400 radiotherapy prostate cancer candidate at the 4th Annual Targeted Radiopharmaceuticals Summit (TRP) being held July 29 – 31, 2025 in San Diego, CA. ATNM-400 is a novel, first-in-class targeted radiotherapy designed to deliver potent Actinium-225 (Ac-225), an alpha-emitter radioisotope, to prostate cancer cells by targeting a non-Prostate Specific Membrane Antigen (PSMA), disease-driving protein overexpressed in advanced and treatment-resistant disease. Unlike PSMA-targeted agents that primarily serve as imaging and targeting tools, the ATNM-400 target is directly implicated in tumor progression, survival signaling, and resistance to androgen receptor (AR) pathway inhibitor (ARPI) therapy. The presentation titled, "Building a Transformative Ac-225 Portfolio for Next-Generation Precision Oncology" on Wednesday, July 30, 2025, highlighted new PET imaging data showing tumor-specific uptake of ATNM-400, robust tumor control and improved survival outcomes in preclinical studies.