Actinium shares jump 11.85% premarket after new pan-tumor data and AACR presentations for ATNM-400 and Actimab-A.

Actinium surged 11.85% in premarket trading following the announcement of new preclinical data for ATNM-400 and Actimab-A, set to be presented at the AACR 2026 meeting. The data highlights ATNM-400’s pan-tumor efficacy in solid tumors and Actimab-A’s mutation-agnostic mechanism in AML, reinforcing the company’s Ac-225 radiotherapy platform. These developments position both assets as potential first-in-class therapies and provide multiple data catalysts in 2026, fueling investor optimism ahead of the April 21 poster presentations.