Actinium Pharmaceuticals Announces ATNM-400 a Novel Non-PSMA Targeting First in Class Prostate Cancer Radiotherapy Leveraging Actinium-225
Actinium Pharmaceuticals (NYSE: ATNM) has unveiled ATNM-400, a groundbreaking non-PSMA targeting radiotherapy for prostate cancer using Actinium-225. Initial preclinical data showed remarkable results with 99.8% tumor growth inhibition at 40 µCi/kg and 68.5% at 20 µCi/kg from a single dose.
The therapy demonstrated selective tumor accumulation for up to 144 hours with minimal uptake in healthy tissues. ATNM-400 differentiates itself from Novartis's Pluvicto by targeting a different marker than PSMA and utilizing the more potent alpha-particle emitter Ac-225, potentially resulting in fewer off-target effects.
The company will present initial data at the AACR Annual Meeting (April 25-30, 2025), including results from Pluvicto-resistant prostate cancer models. The presentation will showcase findings from in vitro and in vivo studies, biodistribution imaging, and efficacy analyses at various dose levels.
Actinium Pharmaceuticals (NYSE: ATNM) ha presentato ATNM-400, una terapia innovativa di radioterapia non mirata al PSMA per il cancro alla prostata che utilizza Actinium-225. I dati preclinici iniziali hanno mostrato risultati straordinari con un'inibizione della crescita tumorale del 99,8% a 40 µCi/kg e del 68,5% a 20 µCi/kg da una singola dose.
La terapia ha dimostrato un'accumulo selettivo nel tumore per un massimo di 144 ore con un'assunzione minima nei tessuti sani. ATNM-400 si distingue dal Pluvicto di Novartis poiché colpisce un marcatore diverso dal PSMA e utilizza l'emettitore di particelle alfa più potente Ac-225, il che potrebbe comportare meno effetti collaterali non mirati.
L'azienda presenterà i dati iniziali al AACR Annual Meeting (25-30 aprile 2025), inclusi i risultati da modelli di cancro alla prostata resistenti a Pluvicto. La presentazione mostrerà i risultati di studi in vitro e in vivo, imaging della biodistribuzione e analisi di efficacia a vari livelli di dosaggio.
Actinium Pharmaceuticals (NYSE: ATNM) ha presentado ATNM-400, una innovadora radioterapia no dirigida al PSMA para el cáncer de próstata que utiliza Actinium-225. Los datos preclínicos iniciales mostraron resultados notables con un 99,8% de inhibición del crecimiento tumoral a 40 µCi/kg y un 68,5% a 20 µCi/kg a partir de una sola dosis.
La terapia demostró una acumulación selectiva en el tumor durante hasta 144 horas con una mínima captación en tejidos sanos. ATNM-400 se diferencia del Pluvicto de Novartis al dirigirse a un marcador diferente al PSMA y utilizar el emisor de partículas alfa más potente, Ac-225, lo que podría resultar en menos efectos fuera del objetivo.
La empresa presentará datos iniciales en el AACR Annual Meeting (25-30 de abril de 2025), incluidos los resultados de modelos de cáncer de próstata resistentes a Pluvicto. La presentación mostrará hallazgos de estudios in vitro e in vivo, imágenes de biodistribución y análisis de eficacia a varios niveles de dosis.
액티니움 제약 (NYSE: ATNM)이 액티니움-225를 이용한 전립선암 치료를 위한 혁신적인 비-PSMA 표적 방사선 치료제인 ATNM-400을 공개했습니다. 초기 전임상 데이터는 40 µCi/kg에서 99.8%의 종양 성장 억제와 20 µCi/kg에서 68.5%를 단일 용량으로 보여주는 놀라운 결과를 나타냈습니다.
이 치료법은 건강한 조직에서의 최소한의 흡수와 함께 최대 144시간 동안 선택적인 종양 축적을 보여주었습니다. ATNM-400은 PSMA와는 다른 표적을 설정하고, 더 강력한 알파 입자 방출기인 Ac-225를 활용함으로써 노바르티스의 플루빅토와 차별화되어, 비표적 효과를 줄일 수 있을 것으로 예상됩니다.
회사는 AACR 연례 회의 (2025년 4월 25-30일)에서 초기 데이터를 발표할 예정이며, 플루빅토에 저항성을 가진 전립선암 모델의 결과를 포함할 것입니다. 발표는 다양한 용량 수준에서의 in vitro 및 in vivo 연구, 생체 분포 이미징 및 효능 분석 결과를 보여줄 것입니다.
Actinium Pharmaceuticals (NYSE: ATNM) a dévoilé ATNM-400, une radiothérapie révolutionnaire non ciblée sur le PSMA pour le cancer de la prostate utilisant l'Actinium-225. Les données précliniques initiales ont montré des résultats remarquables avec une inhibition de la croissance tumorale de 99,8 % à 40 µCi/kg et de 68,5 % à 20 µCi/kg à partir d'une seule dose.
La thérapie a démontré une accumulation sélective dans la tumeur pendant jusqu'à 144 heures avec une absorption minimale dans les tissus sains. ATNM-400 se distingue du Pluvicto de Novartis en ciblant un marqueur différent du PSMA et en utilisant l'émetteur de particules alpha plus puissant Ac-225, ce qui pourrait entraîner moins d'effets hors cible.
La société présentera des données initiales lors de la AACR Annual Meeting (25-30 avril 2025), y compris des résultats de modèles de cancer de la prostate résistants au Pluvicto. La présentation mettra en avant les résultats d'études in vitro et in vivo, d'imagerie de biodistribution et d'analyses d'efficacité à divers niveaux de dosage.
Actinium Pharmaceuticals (NYSE: ATNM) hat ATNM-400 vorgestellt, eine bahnbrechende nicht-PSMA zielgerichtete Radiotherapie für Prostatakrebs unter Verwendung von Actinium-225. Die ersten präklinischen Daten zeigten bemerkenswerte Ergebnisse mit einer Tumorwachstumshemmung von 99,8% bei 40 µCi/kg und 68,5% bei 20 µCi/kg aus einer einzigen Dosis.
Die Therapie zeigte eine selektive Tumorakkumulation von bis zu 144 Stunden mit minimaler Aufnahme in gesundem Gewebe. ATNM-400 unterscheidet sich von Novartis' Pluvicto, da es ein anderes Marker als PSMA anvisiert und den potenteren Alpha-Partikel-Emitter Ac-225 nutzt, was möglicherweise zu weniger Off-Target-Effekten führt.
Das Unternehmen wird erste Daten auf dem AACR Annual Meeting (25.-30. April 2025) präsentieren, einschließlich Ergebnissen aus Pluvicto-resistenten Prostatakrebsmodellen. Die Präsentation wird Ergebnisse aus In-vitro- und In-vivo-Studien, Biodistributionsbildgebung und Wirkungsanalysen auf verschiedenen Dosierungsniveaus zeigen.
- Achieved 99.8% tumor growth inhibition with single dose at 40 µCi/kg
- Demonstrated selective tumor accumulation for up to 144 hours with minimal healthy tissue uptake
- Potential to treat Pluvicto-resistant prostate cancer cases
- Targets different marker than PSMA, potentially reducing common side effects like xerostomia
- Still in preclinical stage, requiring extensive clinical trials before potential commercialization
- Will compete with established treatment Pluvicto ($1.39B sales in 2024)
Insights
Actinium Pharmaceuticals' announcement of ATNM-400 represents a significant scientific advancement in targeted radiotherapy for prostate cancer. The preclinical data showing
What's technically innovative here is ATNM-400's dual differentiation from market leader Pluvicto: it targets a non-PSMA marker and utilizes Actinium-225, an alpha-particle emitter with higher potency and shorter path length than Lutetium-177. This approach could potentially address two critical limitations in current radiotherapeutics: resistance mechanisms and off-target toxicity.
The extended tumor retention time of 144 hours with minimal healthy tissue uptake demonstrates excellent tumor-targeting specificity, which is crucial for the therapeutic window of radiopharmaceuticals. This pharmacokinetic profile suggests ATNM-400 may deliver higher radiation doses to tumors while minimizing collateral damage.
While these results are impressive, they remain preclinical. The path to clinical validation is lengthy and challenging, with many radioconjugates failing to translate preclinical efficacy to humans. However, if ATNM-400 maintains this efficacy profile in clinical trials, it could position Actinium to compete in the lucrative prostate cancer radiotherapeutics market that saw Pluvicto generate
Actinium's ATNM-400 represents a strategic maneuver into the high-value radiopharmaceutical oncology market. The company is directly positioning this candidate to address treatment failures with Novartis' Pluvicto, which achieved
The preclinical data package appears remarkably strong, with the
From a competitive standpoint, ATNM-400's non-PSMA targeting mechanism represents a differentiated approach in a rapidly crowding field of PSMA-targeting radiotherapeutics. This could potentially address the xerostomia (dry mouth) issue reported with PSMA-targeting agents - a quality-of-life limitation that affects patient compliance and satisfaction.
For Actinium Pharmaceuticals, with its current market cap of just
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- ATNM-400 accumulated in tumors for up to 144 hours and showed minimal uptake in healthy tissues in prostate cancer xenograft model
- Initial ATNM-400 preclinical data to be presented at AACR including results in Pluvicto resistant prostate cancer models
Sandesh Seth, Actinium's Chairman and CEO, said, "The current era of radiotherapy is built on the clinical and commercial success of Pluvicto in prostate cancer. The field is now looking to address patients that do not respond or progress after Pluvicto therapy. We believe ATNM-400 can address this high unmet need and we are incredibly excited by our data to date. As anticipated, we have seen robust tumor control and ATNM-400 has shown to be well tolerated in preclinical studies, which we believe is due to the precise and potent cell-killing of Ac-225. We are also highly excited by the results of our biodistribution studies that showed selective tumor uptake with minimal uptake in normal tissues. By focusing on a non-PSMA target, we also believe ATNM-400 has the potential to address some of the toxicities reported with Pluvicto and other PSMA targeting radiotherapies such as xerostomia. We are eager to present our ATNM-400 data at AACR and to continue to advance this highly novel prostate cancer candidate."
Highlights from the abstract include:
- ATNM-400 selectively binds to prostate cancer cells, undergoes rapid internalization, and induces dose-dependent cytotoxicity
- In prostate cancer xenograft mouse models, ATNM-400 accumulated in tumors for up to 144 hours, while showing minimal uptake in normal tissues
- Small animal SPECT/CT imaging with Indium-111-labeled antibody confirmed selective tumor accumulation and clearance from healthy tissues
- A single dose of ATNM-400 achieved
68.5% tumor growth inhibition at 20 µCi/kg and99.8% at 40 µCi/kg, with all doses being well tolerated
ATNM-400 AACR Presentation Details
Title: ATNM-400 is a novel Actinium-225 antibody radioconjugate with strong efficacy in preclinical models of prostate cancer
Abstract Number: 578
Session: PO.ET08.01 - Theranostics and Radiotheranostics
Date & Time: April 27, 2025 – 2:00 pm – 5:00 pm
About Actinium Pharmaceuticals, Inc.
Actinium is a pioneer in the development of targeted radiotherapies intended to meaningfully improve patient outcomes. Actinium is advancing its lead product candidate Actimab-A, a CD33 targeting therapeutic, as potential backbone therapy in acute myeloid leukemia (AML) and other myeloid malignancies leveraging the mutation agnostic alpha-emitter radioisotope payload Actinium-225 (Ac-225). Actimab-A has demonstrated potential activity in relapsed and refractory acute myeloid leukemia (r/r AML) patients in combination with the chemotherapy CLAG-M including high rates of Complete Remissions (CR) and measurable residual disease (MRD) negativity leading to improved survival outcomes and is being advanced to a pivotal Phase 2/3 trial. In addition, Actinium is engaged with the National Cancer Institute (NCI) under the Cooperative Research and Development Agreement (CRADA) for development of Actimab-A in AML and other myeloid malignancies. The first clinical trial under the CRADA will evaluate the triplet combination comprised of Actimab-A, Venetoclax (Abbvie/Roche) an oral Bcl-2 inhibitor and ASTX-727 (Taiho Oncology, an Otsuka holdings company) a novel oral hypomethylating agent (HMA) in frontline acute myeloid leukemia (AML) patients. Additionally, Actinium is developing Actimab-A as a potential pan tumor therapy in combination with PD-1 checkpoint inhibitors including KEYTRUDA® and OPDIVO® by depleting myeloid derived suppressor cells (MDSCs), which represents a potential multi-billion-dollar addressable market. Iomab-ACT, Actinium's next generation conditioning candidate, is being developed with the goal of improving patient access and outcomes for potentially curative cell and gene therapies. Iomab-B is an induction and conditioning agent prior to bone marrow transplant in patients with r/r AML, which Actinium is seeking a potential strategic partner for the
For more information, please visit: https://www.actiniumpharma.com/
Forward-Looking Statements
This press release may contain projections or other "forward-looking statements" within the meaning of the "safe-harbor" provisions of the private securities litigation reform act of 1995 regarding future events or the future financial performance of the Company which the Company undertakes no obligation to update. These statements are based on management's current expectations and are subject to risks and uncertainties that may cause actual results to differ materially from the anticipated or estimated future results, including the risks and uncertainties associated with preliminary study results varying from final results, estimates of potential markets for drugs under development, clinical trials, actions by the FDA and other governmental agencies, regulatory clearances, responses to regulatory matters, the market demand for and acceptance of Actinium's products and services, performance of clinical research organizations and other risks detailed from time to time in Actinium's filings with the Securities and Exchange Commission (the "SEC"), including without limitation its most recent annual report on form 10-K, subsequent quarterly reports on Forms 10-Q and Forms 8-K, each as amended and supplemented from time to time.
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SOURCE Actinium Pharmaceuticals, Inc.
FAQ
What are the key preclinical results for ATNM-400 in prostate cancer treatment?
How does ATNM-400 differ from Pluvicto in treating prostate cancer?
When will Actinium Pharmaceuticals (ATNM) present ATNM-400 data at AACR 2025?
What potential advantages does ATNM-400 offer over existing prostate cancer treatments?
