Actinium shares jump 11.18% after-hours after announcing new preclinical data for ATNM-400 and Actimab-A ahead of AACR 2026.

Actinium Pharmaceuticals surged 11.18% in after-hours trading following the announcement of two upcoming data presentations at the AACR 2026 Annual Meeting on April 21. The company highlighted new preclinical data for ATNM-400, a first-in-class Ac-225 radioconjugate demonstrating pan-tumor activity across multiple solid tumors, and Actimab-A, which showed mutation-agnostic efficacy and a novel mechanism to enhance standard AML therapies. These developments reinforce Actinium’s Ac-225 platform and pipeline potential, generating investor optimism ahead of the data release.