Actinium Pharmaceuticals Unveils ATNM‑400 Data at EANM 2026 with a First‑In‑Human HER3‑Targeted Radiotherapy Approach Beyond PSMA in Prostate Cancer
Actinium reported initial Phase 1 results for ATNM-400 in mCRPC at EANM 2026. In the first three-patient cohort at 1.0 µCi/kg, no dose-limiting toxicities, xerostomia, or Grade 3/4 hematologic adverse events were observed; HER3-targeted imaging showed tumor uptake and retention, and the study advanced to 1.5 µCi/kg.
Why it matters — The update provides early safety and tumor-imaging findings for ATNM-400, a first-in-human Actinium-225 radiotherapy approach targeting HER3 in prostate cancer.