Actinium Pharmaceuticals’ ATNM-400 shows superior anti-tumor activity

Actinium Pharmaceuticals (ATNM) announced the presentation of the first ever preclinical data of ATNM-400 in non-small cell lung cancer, or NSCLC. ATNM-400 is Actinium’s lead solid tumor program, which is also being studied in prostate cancer. ATNM-400 demonstrated superior efficacy with 3-5x greater tumor growth inhibition compared to standard-of-care therapies across EGFR-mutant NSCLC including AstraZeneca’s (AZN) (ASZN) Osimertinib and Dato-DXd and J&J’s (JNJ) Amivantamab. ATNM-400 also demonstrated synergistic activity in combination with osimertinib with complete tumor regression in 100% of tumor-bearing animals. Data of external beam radiotherapy combined with osimertinib resulted in improved progression free survival compared to osimertinib alone, providing a strong clinical rationale for combining targeted alpha-therapy via ATNM-400 with EGFR targeting therapies. ATNM-400 produced superior tumor growth inhibition in animals bearing human lung cancer NCI-H1975. TGI with ATNM-400 was 3-5 times higher than what was achieved with the current standard of care EGFR-mutant NSCLC therapies. The combination of ATNM-400 and osimertinib produced cures in all tumor-bearing animals with complete tumor regression, outperforming either agent alone and suggesting synergistic activity.