Actinium's ATNM-400 shows preclinical activity in therapy-resistant breast cancer models
ATNM•Actinium Pharmaceuticals will present preclinical findings on ATNM-400 at the San Antonio Breast Cancer Symposium on December 9, 2026. The investigational HER3-targeted alpha therapy demonstrated efficacy across treatment-resistant breast cancer subtypes.
1. Preclinical findings
Actinium Pharmaceuticals said it will present preclinical ATNM-400 breast cancer findings at the San Antonio Breast Cancer Symposium on December 9, 2026. The investigational HER3-targeted alpha therapy demonstrated efficacy across treatment-resistant breast cancer subtypes, building on previously reported activity in other solid tumor models. The findings support broader evaluation across solid tumors, alongside ATNM-400's ongoing first-in-human clinical development in prostate cancer.
