- Actinium Pharmaceuticals (ATNM, Financial) showcases promising preclinical results for ATNM-400 at AACR Annual Meeting.
- ATNM-400 demonstrates 99.8% tumor growth inhibition in prostate cancer models, outperforming Pluvicto.
- ATNM-400 uses a novel non-PSMA targeting mechanism, effective even after Pluvicto resistance.
Actinium Pharmaceuticals, Inc. (ATNM), a leader in targeted radiotherapy development, presented groundbreaking preclinical data for its novel prostate cancer treatment, ATNM-400, at the American Association for Cancer Research (AACR) Annual Meeting. ATNM-400, which leverages the alpha-particle emitter Actinium-225, demonstrated superior efficacy to Pluvicto by achieving a 99.8% tumor growth inhibition with a single dose of 40 µCi/kg in prostate cancer models.
Unlike Pluvicto, which targets the prostate-specific membrane antigen (PSMA), ATNM-400 employs a first-in-class approach by targeting a distinct non-PSMA receptor. This receptor remains highly expressed even after Pluvicto treatment, allowing for sustained tumor control in cases where Pluvicto stops being effective. The preclinical studies highlight ATNM-400's ability to effectively inhibit tumor growth in Pluvicto-resistant models, showcasing its potential as an alternative therapeutic option.
The alpha-particle emitter Actinium-225 offers several advantages over Pluvicto's Lutetium-177 beta-emitter, such as causing lethal double-strand DNA breaks with a shorter path length, reducing off-target effects. Moreover, biodistribution analyses show that ATNM-400 is rapidly internalized and remains in the targeted tumor tissue while efficiently clearing from essential organs like the blood, liver, kidneys, and intestines.
ATNM-400 was well-tolerated across varying dosage levels, with no apparent toxicities detected in preclinical models. These promising results indicate ATNM-400's potential to address unmet clinical needs in prostate cancer treatments, particularly for patients who have developed resistance to current therapies like Pluvicto.
