Actinium Pharmaceuticals, Inc. (NYSE: ATNM) shares began Wednesday virtually unchanged. The company, a pioneer in differentiated targeted radiotherapies with the potential to transform cancer treatment, today announced that the RADIANZ clinical trial is enrolling patients. RADIANZ is an imaging study of 8?Zr-Barecetamab-DFO using PET to guide the pan-tumor development of ²²5Ac-Barecetamab-DOTA (ATNM-400) in solid tumors outside of prostate cancer.
RADIANZ builds on ATNM-400's first-in-human Phase 1 study in metastatic castration-resistant prostate cancer (mCRPC). ATNM-400 is an investigational, first-in-class Actinium-225 antibody radioconjugate targeting HER3, an antigen implicated in tumor survival and treatment resistance across multiple solid tumors. Initial results from that study were presented in October as an oral presentation at the 39th Annual Congress of the European Association of Nuclear Medicine (EANM). The first three patients received ATNM-400 at 1.0 µCi/kg with no dose-limiting toxicities, HER3-targeted PET imaging showed tumor uptake retained through Day 7, and dose escalation advanced to 1.5 µCi/kg.
The mCRPC study was also featured in at the European Society for Medical Oncology (ESMO) Congress 2026. At EANM 2026, Actinium presented preclinical data in NSCLC, colorectal and ovarian cancer models demonstrating the potential of ATNM-400 as either a single agent of in combination with approved drugs.
The Company will also present additional breast cancer data for ATNM-400 at the San Antonio Breast Cancer Symposium (SABCS) taking place December 8-11.
ATNM shares inched up $0.009 to $1.5688
