Actinium Pharma Reports New Preclinical Data From Non-PSMA Targeting Radiotherapy Prostate Cancer Candidate ATNM-400, At SNMMI Annual Meeting

-  ATNM-400 shows; superior prostate cancer cell killing compared to androgen receptor inhibitor Xtandi® (enzalutamide), the ability to overcome Xtandi resistance, and activity in combination

-  ATNM-400 is more efficacious than both Pluvicto® (177-Lu-PSMA-617) and Ac-225-PSMA-617 targeted radiotherapy in prostate cancer in vitro and in vivo models and overcome resistance in prostate cancer tumors that failed Pluvicto® therapy

-  ATNM-400's target is highly differentiated from PSMA as it is implicated in disease biology, contributing to disease progression, faster progression to castration resistance and poorer survival outcomes with target expression reported following androgen receptor inhibitor and PSMA radiotherapy

-  Data further supports ATNM-400's potential to address critical gaps in prostate cancer treatment as a monotherapy or in sequence with other therapeutic modalities

NEW YORK, June 23, 2025 /PRNewswire/ -- Actinium Pharmaceuticals, Inc. (NYSE:ATNM) (Actinium or the Company), a pioneer in the development of targeted radiotherapies, today reported new preclinical data from its first-in-class, non-PSMA targeting radiotherapy prostate cancer candidate ATNM-400, that leverages the potent alpha-particle emitter Actinium-225 (Ac-225) isotope, at the Society of Nuclear Medicine & Molecular Imaging (SNMMI) annual meeting being held June 21st – 24th, 2025, in New Orleans, Louisiana. The data presented at SNMMI showed ATNM-400 has superior potency compared Xtandi® (enzalutamide) and is highly efficacious in Xtandi® resistant prostate models. Xtandi is an androgen receptor inhibitor (ARPI) therapy developed and marketed by Astellas and Pfizer that is approved for three stages of prostate cancer and generated sales of $5.9 billion in 2024. Actinium also presented additional new data showing ATNM-400 is more efficacious than PSMA-617 labeled with both Lutetium-177 (Lu-177) and Ac-225 and that ATNM-400 also overcomes resistance to Pluvicto® (Lu-177-PSMA-617). Pluvicto® is developed and marketed by Novartis and generated sales of $1.4 billion in 2024. ATNM-400 represents a transformational therapeutic candidate being developed to overcome limitations of current prostate cancer therapies such as Xtandi® and Pluvicto® and improve outcomes over what is currently achievable.