Actinium announces positive ATNM-400 results in prostate cancer

Actinium announced ATNM-400, a novel, non-PSMA targeting, first in class radiotherapy for prostate cancer utilizing the Actinium-225 radioisotope. Initial preclinical data from ATNM-400 will be presented at the American Association for Cancer Research Meeting April 25-30 in Chicago. The ATNM-400 AACR abstract will include the results from in vitro and in vivo studies including biodistribution imaging and efficacy analyses with various dose levels of ATNM-400. ATNM-400 is Actinium’s novel non-PSMA targeting Ac-225 radiotherapy for prostate cancer. ATNM-400 selectively binds to prostate cancer cells, undergoes rapid internalization, and induces dose-dependent cytotoxicity; in prostate cancer xenograft mouse models, ATNM-400 accumulated in tumors for up to 144 hours, while showing minimal uptake in normal tissues; small animal SPECT/CT imaging with Indium-111-labeled antibody confirmed selective tumor accumulation and clearance from healthy tissues. A single dose of ATNM-400 achieved 68.5% tumor growth inhibition at 20 microCi/kg and 99.8% at 40 microCi/kg, with all doses being well tolerated.