Actinium reports broad ATNM-400 activity in cancer models at EANM 2026
Actinium Pharmaceuticals presented EANM 2026 data showing its HER3-targeted Actinium-225 therapy ATNM-400 was active across lung, colorectal and ovarian cancer models. The studies covered EGFR-, KRAS- and ALK-driven lung tumors, treatment-resistant disease and combinations with established therapies. In colorectal cancer, the combination with oxaliplatin and bevacizumab produced 72% tumor growth inhibition versus 25% for the standard combination, while ovarian-cancer monotherapy produced 93% tumor growth inhibition.
Why it matters
The results expand ATNM-400's preclinical development opportunity across several solid-tumor indications and support Actinium's stated strategy of pursuing both monotherapy and combination uses. The data remain preclinical for these indications, while the company is also conducting clinical development in prostate cancer.
Key facts
- 1Actinium said the findings were presented in an oral session and two e-posters at the European Association of Nuclear Medicine Congress in Vienna during October 17–21, 2026. prnewswire.com
- 2In a KRAS G12C-mutant lung-cancer model, ATNM-400 monotherapy achieved 81% tumor growth inhibition, compared with 38% for adagrasib and 29% for patritumab deruxtecan, while the combination with adagrasib reached 105%. prnewswire.com
- 3In a colorectal-cancer model, ATNM-400 with oxaliplatin and bevacizumab achieved 72% tumor growth inhibition, versus 25% for oxaliplatin and bevacizumab alone and 27% for ATNM-400 alone. prnewswire.com
- 4ATNM-400 monotherapy achieved 93% tumor growth inhibition in an ovarian-cancer model and remained active after bevacizumab failure. prnewswire.com
- 5Actinium is developing ATNM-400 in a Phase 1 study for metastatic castration-resistant prostate cancer while evaluating additional solid-tumor indications. prnewswire.com
Summary written by AlphAI AI Desk from 7 of 7 sources. Not investment advice. Figures are as stated by the linked sources.