#United States #New York #Actinium-225 #Actinium Pharmaceuticals #ATNM-400

Actinium Pharmaceuticals Introduces ATNM-400: A Novel Radiotherapy for Prostate Cancer

Actinium Pharmaceuticals, Inc., a leader in targeted radiotherapies, has recently introduced a revolutionary treatment option for prostate cancer, named ATNM-400. This innovative therapy leverages the properties of the Actinium-225 isotope and targets a non-PSMA marker, aiming to provide a better alternative for patients who may not respond to existing treatments like Pluvicto (Lu-177-PSMA-617).

Overview of ATNM-400

ATNM-400 has demonstrated remarkable efficacy in preclinical studies, achieving a staggering 99.8% inhibition of tumor growth after a single administration in various prostate cancer models. This new treatment has exhibited a unique capability to accumulate in tumors for up to 144 hours while minimizing uptake in healthy surrounding tissues. Such characteristics suggest that ATNM-400 could potentially reduce adverse side effects commonly associated with cancer therapies.

Preclinical findings will be showcased during the upcoming American Association for Cancer Research (AACR) Annual Meeting, scheduled from April 25 to April 30, 2025, in Chicago, Illinois. The presentation will feature detailed methodologies and outcomes from in vitro and in vivo studies, emphasizing biodistribution imaging and efficacy results across different doses of ATNM-400.

Mechanism of Action

Unlike PSMA-directed therapies, ATNM-400 selectively binds to prostate cancer cells with rapid internalization and demonstrates a dose-dependent cytotoxic effect. By employing Actinium-225, a potent alpha-particle emitter that offers a shorter path length, the treatment aims to enhance the specificity of tumor targeting, thereby minimizing damage to healthy cells.

Preliminary Findings

• - ATNM-400 showed 68.5% tumor growth inhibition at a dose of 20 µCi/kg and an impressive 99.8% at 40 µCi/kg.
• - The study confirmed selective accumulation in tumor tissues and clearance from healthy areas via small animal SPECT/CT imaging with Indium-111-labeled antibodies.
• - Tolerability of ATNM-400 was confirmed across all tested doses, which is promising for patient safety and comfort.

Addressing Unmet Medical Needs

In light of the success of Pluvicto, which generated significant revenue in 2024, there is an evident demand for innovative therapies that target patients with progressed or resistant prostate cancer. Sandesh Seth, the CEO of Actinium, articulated the urgency of addressing this niche, stating, "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."

Seth expressed optimism regarding ATNM-400, highlighting its potential to meet significant unmet needs in cancer treatment. He remarked on the encouraging tumor control observed in preclinical studies, attributing the positive results to the targeted and potent effects of Ac-225.

Upcoming Presentation at AACR

The AACR presentation will provide further insight into the capabilities of ATNM-400. Key details include:

• - 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
• - Presentation Date and Time: April 27, 2025, from 2:00 PM to 5:00 PM

By focusing on less common targets, ATNM-400 aims to minimize the risk of toxicities often linked with other PSMA targeting therapies, such as xerostomia. This aspect positions ATNM-400 as a promising option in the evolving landscape of prostate cancer treatments.

Looking Ahead

Actinium Pharmaceuticals continues to back ATNM-400 as a key player in its development pipeline. Alongside Actimab-A, another promising candidate for acute myeloid leukemia, the company is expanding its research endeavors to enhance treatment options available in oncology. With a commitment to innovation, Actinium aims to redefine cancer care through advanced radiotherapy solutions.

For ongoing updates and detailed information about Actinium's initiatives, please visit their official website.