On October 16, 2026 Actinium Pharmaceuticals, Inc. (NYSE American: ATNM) (Actinium or the Company), a pioneer in differentiated targeted radiotherapies with the potential to transform cancer treatment, reported three presentations, including an oral presentation and two e-posters, highlighting preclinical data supporting ATNM-400’s broad potential at the 39th Annual Congress of the European Association of Nuclear Medicine (EANM), October 17–21, 2026, in Vienna, Austria.
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The presentations feature ATNM-400, the Company’s first-in-class Actinium-225 (²²⁵Ac) radiotherapy, in non-small cell lung cancer (NSCLC), colorectal cancer, and ovarian cancer models. Together, the studies demonstrate preclinical antitumor activity as monotherapy and enhanced activity in combination with standard-of-care agents, supporting both approaches to development across solid tumors. These findings further expand the preclinical evidence supporting ATNM-400’s potential across multiple cancer indications, complementing its ongoing clinical development in metastatic castration-resistant prostate cancer (mCRPC).
In NSCLC, ATNM-400 demonstrated antitumor activity as monotherapy and enhanced activity in combination with KRAS or ALK inhibitors, including in resistant models. These findings extend earlier EGFR-mutant results and support mutation-agnostic development both as a standalone therapy and in combination with established treatments.
In colorectal cancer, ATNM-400 demonstrated monotherapy activity in SW620 xenografts and enhanced activity when combined with bevacizumab plus oxaliplatin in HCT15 xenografts, a model with moderate target expression and limited response to the standard-of-care combination. These findings support both monotherapy development and combinations aimed at improving outcomes in poorly responsive disease.
In ovarian cancer, ATNM-400 monotherapy produced durable antitumor activity, including in bevacizumab-refractory tumors. These findings support its potential as a standalone treatment in recurrent disease, with further evaluation of ATNM-400 alone and in combination with standard-of-care therapies extending this development strategy.
"These findings build a compelling preclinical foundation for ATNM-400’s pan-cancer potential and our vision to expand targeted radiotherapy across major solid tumor indications," said Sandesh Seth, Actinium’s Chairman and CEO. "The high prevalence of ATNM-400’s target in NSCLC, coupled with activity in KRAS- and ALK-driven models that builds on our earlier EGFR-mutant findings, supports the potential to reach a broad lung cancer population regardless of oncogenic mutation. Encouraging results in colorectal and treatment-resistant ovarian cancer models further extend this opportunity into areas of significant unmet need. Together, these data support our strategy to develop ATNM-400 as both a standalone therapy and a combination partner for established treatments, with the potential to address multiple large patient populations."
ATNM-400 EANM 2026 Presentation Details
Abstract Title: ATNM-400 Elicits Durable Anti-tumor Responses in KRAS- and ALK-Driven NSCLC Models in a Mutation-Agnostic Manner
Abstract Number: EPS-149
Presentation Type: Oral presentation
Session: 1109 — Translational Imaging and Therapy
Session Date & Time: Monday, October 19, 2026, 4:45–6:15 p.m. CEST | Vienna, Austria
Location: Hall G2
Abstract Title: ATNM-400, a First-in-Class Actinium-225 Radioconjugate Improves Response to Standard-of-Care Therapeutics in Colorectal Cancer Models
Abstract Number: EP-0163
Presentation Type: e-Poster
Abstract Title: ATNM-400, a First-in-Class Actinium-225 Radioconjugate Triggers Durable Antitumor Responses in Ovarian Cancer Models
Abstract Number: EP-0176
Presentation Type: e-Poster
(Press release, Actinium Pharmaceuticals, OCT 16, 2026, View Source [SID1234673526])