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• New data demonstrated ATNM-400 remains potently active in prostate cancer cells and tumors resistant to all three approved androgen receptor inhibitors (ARPIs) -enzalutamide (Xtandi®), apalutamide (Erleada®), and darolutamide (Nubeqa®)- directly targeting the point of failure for a high proportion of mCRPC patients
• ATNM-400 substantially outperformed apalutamide and darolutamide in an ARPI-resistant tumor model, and in combination with either ARPI it showed durable complete responses, supporting both monotherapy and combination strategies in refractory disease similar to prior data with enzalutamide
• ATNM-400 delivered superior tumor control as a single bolus or repeat dose with a consistent safety profile and minimal off-target toxicity across treatment regimens, indicating dosing flexibility and a wide therapeutic window that could de-risk clinical translation.
• In high PSMA expressing disease, ATNM-400 outperformed 177Lu-PSMA-617 in terms of activity and was similar to 225Ac-PSMA-617. However, as its target is not expressed in the salivary glands, ATNM-400 is not expected to cause xerostomia which is a key limitation of PSMA directed therapies
NEW YORK,June 3, 2026/PRNewswire/ --Actinium Pharmaceuticals, Inc.(NYSE American: ATNM) (Actinium or the Company), a pioneer in the development of targeted radiotherapies, on June 2, 2026, presented new data on ATNM-400 in prostate cancer at the Society of Nuclear Medicine and Molecular Imaging (SNMMI) 2026 Annual Meeting taking place in Los Angeles, California.