Actinium Pharmac Stock Price, News & Analysis

Actinium Pharmaceuticals (NYSE: ATNM) will present preclinical data for ATNM-400, a first-in-class Actinium-225 antibody radioconjugate, showing potent anti-tumor activity in triple-negative breast cancer (TNBC) and efficacy in models resistant to tamoxifen and trastuzumab. Data include tumor growth inhibition exceeding 100% at higher doses, elevated target expression in resistant lines, combination activity with standard agents, and a favorable tolerability profile in xenograft models. The program also showed activity in metastatic castrate-resistant prostate cancer and non-small cell lung cancer. The presentation is scheduled for December 11, 2025 at 5:00 PM CT at the San Antonio Breast Cancer Symposium.

Actinium Pharmaceuticals (NYSE: ATNM) is prioritizing ATNM-400, an Ac-225 alpha-emitter pan-tumor candidate, alongside clinical assets Actimab-A and Iomab-ACT as it targets the growing targeted radiotherapy market. Actinium lists ~250 issued and pending patents and reports preclinical data showing ATNM-400 produced superior tumor control versus 177Lu-PSMA-617 and achieved 40% complete tumor regressions in combination with enzalutamide in animal models. The company disclosed a competitive and regulatory backdrop including a Novartis objection letter (Aug 2025) and noted market context where RLT is estimated at $25–$30B and Pluvicto sales reached about $1.4B in early 2025.

Actinium Pharmaceuticals (NYSE:ATNM) announced that preclinical data for its lead Ac-225 antibody radioconjugate ATNM-400 will be presented at the 2025 San Antonio Breast Cancer Symposium on Dec 11, 2025 (Poster PS4-04-26).

Data show anti-tumor activity of ATNM-400 in tamoxifen- and trastuzumab-resistant breast cancer models and confirm efficacy signals across prostate cancer and NSCLC, including durable tumor control beyond 100 days, complete regressions in combination models (prostate 40%, NSCLC 100%), and synergy with enzalutamide and osimertinib. The company frames ATNM-400 as a multi-indication candidate targeting major oncology markets.

Actinium Pharmaceuticals (NYSE American: ATNM) announced that Sandesh Seth, Chairman and CEO will participate in the Stephens Biotechnology Virtual Fireside Chat on November 4, 2025 from 10:30–11:20 am ET. Company management will be available for one-on-one investor meetings during the virtual event. Investors or advisors seeking to join meetings or request more information should contact their Stephens representative.

Actinium (NYSE AMERICAN: ATNM) on Oct 27, 2025 announced preclinical ATNM-400 NSCLC data showing 3–5x greater tumor growth inhibition versus frontline osimertinib, second-line Dato-DXd and third-line amivantamab in EGFR‑mutant models. Combination with osimertinib produced 100% complete tumor regression in treated animals, with synergy linked to increased ATNM-400 target antigen expression after EGFR inhibition. The release frames ATNM-400 as a first‑in‑class Ac‑225 antibody radioconjugate with potential across first–third line settings and cites ~$7B 2024 sales for approved EGFR‑mutant therapies (osimertinib $6.6B) to illustrate market opportunity.

Actinium Pharmaceuticals (NYSE: ATNM) presented preclinical data on ATNM-400, a first-in-class Ac-225 antibody radioconjugate targeting a non-PSMA antigen, at the 32nd Annual Prostate Cancer Foundation Scientific Retreat on Oct 24, 2025. ATNM-400 showed superior tumor control and prolonged survival versus enzalutamide, 177Lu-PSMA-617 and 225Ac-PSMA-617 in 22Rv1 and other models, including ~5× longer tumor control and ~2× longer overall survival versus 177Lu-PSMA-617. Combination with enzalutamide produced complete regressions in 40% of animals. Data support PSMA-independent activity and potential use as monotherapy, combination, or sequential therapy.

Actinium Pharmaceuticals (NYSE: ATNM) announced that first-ever preclinical data for ATNM-400, a first-in-class Actinium-225 antibody radioconjugate, will be presented at the AACR-NCI-EORTC conference Oct 22–26, 2025.

Preclinical findings reportedly show potent anti-tumor activity in EGFR-mutant NSCLC models, overcoming resistance to osimertinib and showing synergy with osimertinib and with enzalutamide in prostate models; animal data included 40% complete tumor regressions in a prostate setting. The poster is scheduled for Oct 25, 2025, and the abstract will be available online Oct 22, 2025 at 12:00 PM ET.

Actinium (NYSE: ATNM) announced that preclinical data for ATNM-400, a first-in-class Ac-225 antibody radioconjugate, will be presented at the 32nd Annual Prostate Cancer Foundation Scientific Retreat on October 23, 2025. The poster highlights durable anti-tumor activity in metastatic castration-resistant prostate cancer models, including activity in tumors resistant to enzalutamide and 177Lu-PSMA-617, and reports superior efficacy versus 225Ac-PSMA-617.

The release states ATNM-400 targets a distinct, non-PSMA antigen that is overexpressed after ARPI therapy, showed synergy with enzalutamide, and improved overall survival in preclinical models. The poster will be viewable online via the company investor relations page after the retreat.

Actinium Pharmaceuticals (NYSE AMERICAN: ATNM) has presented promising preclinical data for ATNM-400, its novel targeted radiotherapy for prostate cancer, at the 4th Annual Targeted Radiopharmaceuticals Summit. The therapy demonstrated superior efficacy compared to Pluvicto® and showed effectiveness in treatment-resistant cases.

Key findings include tumor-specific uptake lasting up to 216 hours, significant survival improvements versus Pluvicto®, and effectiveness against Pluvicto®-resistant tumors. Notably, when combined with enzalutamide (Xtandi®), ATNM-400 achieved complete cures in 40% of prostate cancer tumor-bearing animals. The company expects additional data in the second half of 2025.