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Actinium to present ATNM-400 prostate cancer trial data at ESMO 2026

Fri, 23 Oct 2026 08:00:35 -0400

Actinium Pharmaceuticals, Inc. (NYSE American: ATNM) announced that data from a first-in-human Phase 1 study of its investigational drug ATNM-400 will be presented at the European Society for Medical Oncology Congress 2026, held October 23–27 in Madrid, Spain.

ATNM-400 is an Actinium-225 antibody radioconjugate that targets HER3, a protein distinct from PSMA that is associated with tumor growth and treatment resistance. The ongoing multicenter, open-label dose-escalation study enrolls patients with metastatic castration-resistant prostate cancer (mCRPC) who have previously received an androgen receptor pathway inhibitor and taxane-based chemotherapy. Prior treatment with lutetium is permitted but not required.

The study uses Zirconium-89-labeled ATNM-400 imaging

Actinium Pharmaceuticals to Highlight First-in-Human Phase 1 Study of ATNM-400 a HER3-Targeted Non-PSMA Radiotherapy in Prostate Cancer at ESMO 2026

Fri, 23 Oct 2026 08:00:00 -0400

First‑in‑human Phase 1 study evaluates HER3‑targeted ATNM‑400 in metastatic castration‑resistant prostate cancer population, including patients with and without prior PSMA‑directed therapy
HER3‑targeted alpha radiotherapy offers a differentiated approach through a target distinct from PSMA and the potential to address treatment resistance across multiple solid tumors

Actinium Pharmaceuticals to Highlight First-in-Human Phase 1 Study of ATNM-400 a HER3-Targeted Non-PSMA Radiotherapy in Prostate Cancer at ESMO 2026

Fri, 23 Oct 2026 08:00:00 -0400

First‑in‑human Phase 1 study evaluates HER3‑targeted ATNM‑400 in metastatic castration‑resistant prostate cancer population, including patients with and without prior PSMA‑directed therapy
HER3‑targeted alpha radiotherapy offers a differentiated approach through a target distinct from PSMA and the potential to address treatment resistance across multiple solid tumors

Actinium shares early ATNM-400 prostate cancer trial data at EANM

Tue, 20 Oct 2026 08:03:16 -0400

Actinium Pharmaceuticals, Inc. (NYSE American: ATNM) presented initial clinical results from a first-in-human Phase 1 study of ATNM-400, an investigational HER3-targeted alpha radiotherapy for metastatic castration-resistant prostate cancer (mCRPC), at the 39th Annual Congress of the European Association of Nuclear Medicine in Vienna, Austria on Oct. 19.

ATNM-400 pairs the monoclonal antibody barecetamab with Actinium-225, an alpha-emitting isotope with a 10-day half-life. The study uses a theranostic approach, employing Zirconium-89-labeled barecetamab PET imaging to assess tumor uptake and inform dosing.

The first cohort of three patients with previously treated mCRPC received ATNM-400 at 1.0 µCi/kg. All had prior androgen receptor pathway inhibitor

Actinium Pharmaceuticals Unveils ATNM‑400 Data at EANM 2026 with a First‑In‑Human HER3‑Targeted Radiotherapy Approach Beyond PSMA in Prostate Cancer

Tue, 20 Oct 2026 08:00:00 -0400

HER3‑targeted PET imaging demonstrated tumor uptake and retention, supporting ATNM‑400's potential to deliver sustained alpha radiation to tumors over a timeframe consistent with Actinium‑225's 10-day half‑life
Initial three‑patient cohort completed the first dose level of 1.0 µCi/kg with no dose‑limiting toxicities, xerostomia or Grade 3/4 hematologic adverse

Actinium Pharmaceuticals Unveils ATNM‑400 Data at EANM 2026 with a First‑In‑Human HER3‑Targeted Radiotherapy Approach Beyond PSMA in Prostate Cancer

Tue, 20 Oct 2026 08:00:00 -0400

HER3‑targeted PET imaging demonstrated tumor uptake and retention, supporting ATNM‑400's potential to deliver sustained alpha radiation to tumors over a timeframe consistent with Actinium‑225's 10-day half‑life
Initial three‑patient cohort completed the first dose level of 1.0 µCi/kg with no dose‑limiting toxicities, xerostomia or Grade 3/4 hematologic adverse

Actinium shares preclinical data on ATNM-400 across three cancer types

Tue, 20 Oct 2026 07:31:18 -0400

Actinium Pharmaceuticals (NYSE American: ATNM) presented preclinical results for its investigational drug ATNM-400 at the 39th Annual Congress of the European Association of Nuclear Medicine (EANM), held Oct. 17–21, 2026, in Vienna, Austria. The data covered non-small cell lung cancer (NSCLC), colorectal cancer, and ovarian cancer models.

ATNM-400 is an antibody radioconjugate that pairs a HER3-targeting monoclonal antibody with the alpha-emitting isotope Actinium-225. The compound is currently in a Phase 1 clinical study in metastatic castration-resistant prostate cancer.

In NSCLC, the drug showed activity across EGFR-mutant, KRAS G12C-mutant, and ALK-rearranged models. In the KRAS G12C-mutant model, ATNM-400 monotherapy achieved 81% tumor growth

Actinium shares preclinical data on ATNM-400 across three cancer types

Tue, 20 Oct 2026 07:31:18 -0400

In NSCLC, the drug showed activity across EGFR-mutant, KRAS G12C-mutant, and ALK-rearranged models. In the KRAS G12C-mutant model, ATNM-400 monotherapy achieved 81% tumor growth

Actinium Pharmaceuticals Presents EANM 2026 Results Reinforcing ATNM-400's Pan-Tumor Potential Across Lung, Colorectal and Ovarian Cancer Models

Tue, 20 Oct 2026 07:30:00 -0400

ATNM-400 demonstrated activity across EGFR-, KRAS- and ALK-driven lung cancer models, supporting mutation-agnostic development as monotherapy and in combination with established treatments
In colorectal cancer, adding ATNM-400 to standard therapy increased tumor growth inhibition to 72% from 25% for oxaliplatin and

Actinium Pharmaceuticals Presents EANM 2026 Results Reinforcing ATNM-400's Pan-Tumor Potential Across Lung, Colorectal and Ovarian Cancer Models

Tue, 20 Oct 2026 07:30:00 -0400

ATNM-400 demonstrated activity across EGFR-, KRAS- and ALK-driven lung cancer models, supporting mutation-agnostic development as monotherapy and in combination with established treatments
In colorectal cancer, adding ATNM-400 to standard therapy increased tumor growth inhibition to 72% from 25% for oxaliplatin and

Actinium Pharmaceuticals to Showcase ATNM-400's First-in-Human Clinical Data in Prostate Cancer and Preclinical Results in Lung Cancer Supporting Pan-Tumor Potential Today at EANM 2026

Mon, 19 Oct 2026 07:30:00 -0400

First-in-human Phase 1 presentation to feature ATNM-400 clinical data in metastatic castration-resistant prostate cancer, advancing a differentiated approach beyond PSMA
Preclinical presentation to feature ATNM-400 studies in KRAS- and ALK-driven non-small cell lung cancer, exploring its potential across molecular subtypes

Actinium Pharmaceuticals to Showcase ATNM-400's First-in-Human Clinical Data in Prostate Cancer and Preclinical Results in Lung Cancer Supporting Pan-Tumor Potential Today at EANM 2026

Mon, 19 Oct 2026 07:30:00 -0400

First-in-human Phase 1 presentation to feature ATNM-400 clinical data in metastatic castration-resistant prostate cancer, advancing a differentiated approach beyond PSMA
Preclinical presentation to feature ATNM-400 studies in KRAS- and ALK-driven non-small cell lung cancer, exploring its potential across molecular subtypes

Form 4 Actinium Pharmaceuticals For: Oct 14 Filed by: David Matthew T

Fri, 16 Oct 2026 17:11:00 -0400

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Form 3 Actinium Pharmaceuticals For: Oct 14 Filed by: David Matthew T

Fri, 16 Oct 2026 17:11:00 -0400

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Actinium Pharmaceuticals Announces Inducement Grants to New Employees

Fri, 16 Oct 2026 17:00:00 -0400

NEW YORK, Oct. 16, 2026 /PRNewswire/ -- Actinium Pharmaceuticals, Inc. (NYSE American: ATNM) ("Actinium" or the "Company"), a pioneer in the development of targeted radiotherapies, today announced inducement equity awards to Matt David, M.D., the Company's newly appointed Chief Financial Officer, and Sean Maenpaa, the Company's newly appointed Senior Vice President, Business Development.

Actinium Pharmaceuticals Announces Inducement Grants to New Employees

Fri, 16 Oct 2026 17:00:00 -0400

Actinium to present ATNM-400 cancer data at EANM 2026

Fri, 16 Oct 2026 08:31:01 -0400

Actinium Pharmaceuticals, Inc. (NYSE American: ATNM) will present preclinical data on its Actinium-225 radiotherapy candidate ATNM-400 at the 39th Annual Congress of the European Association of Nuclear Medicine (EANM), held October 17–21, 2026, in Vienna, Austria.

The company will deliver one oral presentation and two e-poster presentations covering ATNM-400 activity in non-small cell lung cancer (NSCLC), colorectal cancer, and ovarian cancer models.

The oral presentation, scheduled for October 19, will cover ATNM-400 activity in KRAS- and ALK-driven NSCLC models, including in resistant models. The data extend earlier findings in EGFR-mutant NSCLC and are intended to support a mutation-agnostic development approach.

In colorectal cancer,

Actinium Pharmaceuticals Announces Oral and Poster Presentations at EANM 2026 Highlighting Broad Antitumor Activity of ATNM-400 Across Lung, Colorectal and Ovarian Cancer Models

Fri, 16 Oct 2026 08:30:00 -0400

Oral presentation to highlight ATNM-400 antitumor activity across KRAS- and ALK-driven NSCLC models, building on earlier EGFR-mutant findings and supporting mutation-agnostic development
Colorectal cancer data demonstrate ATNM-400's potential to enhance responses to standard-of-care therapies

Actinium Pharmaceuticals Announces Oral and Poster Presentations at EANM 2026 Highlighting Broad Antitumor Activity of ATNM-400 Across Lung, Colorectal and Ovarian Cancer Models

Fri, 16 Oct 2026 08:30:00 -0400

Oral presentation to highlight ATNM-400 antitumor activity across KRAS- and ALK-driven NSCLC models, building on earlier EGFR-mutant findings and supporting mutation-agnostic development
Colorectal cancer data demonstrate ATNM-400's potential to enhance responses to standard-of-care therapies

Form ARS Actinium Pharmaceuticals For: Dec 31

Fri, 16 Oct 2026 07:51:00 -0400

si-local-file:///var/storage/secattach/20261016/27195772.html

Form DEF 14A Actinium Pharmaceuticals For: Nov 25

Fri, 16 Oct 2026 07:43:00 -0400

si-local-file:///var/storage/secattach/20261016/27195735.html

Actinium Pharmaceuticals names Sean Maenpaa as SVP of business development

Fri, 16 Oct 2026 07:30:42 -0400

Actinium Pharmaceuticals, Inc. (NYSE American: ATNM) has appointed Sean Maenpaa as Senior Vice President, Business Development, effective October 12, 2026, according to a company statement.

Maenpaa will oversee out-licensing, partnering, collaboration transactions, in-licensing opportunities, and corporate development strategy for Actinium's targeted radiotherapy pipeline.

Maenpaa brings more than 20 years of experience in oncology business development and commercial leadership across the radiopharmaceutical sector. He previously served as Managing Director of Maenpaa Consulting LLC, providing strategic support to private equity and investment banks focused on oncology radiopharmaceuticals.

Before his consultancy, Maenpaa was Vice President, Commercial, at BWXT Medical, where he oversaw business development and sales

Actinium Pharmaceuticals Appoints Radiopharmaceutical Industry Veteran Sean Maenpaa as Senior Vice President, Business Development

Fri, 16 Oct 2026 07:30:00 -0400

– Brings more than 20 years of oncology business development and commercial leadership, including senior roles across the radiopharmaceutical sector at Bayer, Clovis Oncology, Telix Pharmaceuticals and BWXT Medical

– Will lead partnering, licensing and strategic transactions across Actinium's targeted radiotherapy pipeline

NEW YORK,

Actinium Pharmaceuticals Appoints Radiopharmaceutical Industry Veteran Sean Maenpaa as Senior Vice President, Business Development

Fri, 16 Oct 2026 07:30:00 -0400

– Will lead partnering, licensing and strategic transactions across Actinium's targeted radiotherapy pipeline

NEW YORK,

Form 8-K Actinium Pharmaceuticals For: Oct 14

Thu, 15 Oct 2026 17:05:00 -0400

si-local-file:///var/storage/secattach/20261015/27194105.html