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Actinium Pharmaceuticals Announces ATNM-400 Data Demonstrating Potent Efficacy in Triple-Negative Breast Cancer and Ability to Overcome Endocrine and HER2-Targeted Therapy Resistance Being Presented at the San Antonio Breast Cancer Symposium
Actinium Pharmaceuticals, Inc. (NYSE American: ATNM), a leader in the development of differentiated targeted radiotherapies, today announced compelling preclinical data for ATNM-400, a first-in-class Actinium-225 (AC-225) antibody radioconjugate, in hormone receptor positive (HR+), HER2 positive (HER2+) and triple-negative breast cancer (TNBC) that will be presented at the San Antonio Breast Cancer Symposium (SABCS) being held December 10‑14, 2025 in San Antonio, Texas. The data demonstrates sig
About this update from Actinium Pharmaceuticals, Inc. (delaware)
[{"type":"list","items":[{"val":[{"type":"text","content":"Presentation to include new data in triple-negative disease, a breast cancer subtype with poor outcomes and limited viable treatment options","length":140,"tagName":"p"}]},{"val":[{"type":"text","content":"ATNM-400 overcomes HER2 therapy resistance and represents a novel targeted radiotherapy with the potential to avoid off-target toxicities including ILD that constrains other therapeutic modalities such as antibody drug conjugates","length":229,"tagName":"p"}]},{"val":[{"type":"text","content":"ATNM-400 has demonstrated the potential to overcome resistance to first-line tamoxifen endocrine therapy","length":104,"tagName":"p"}]},{"val":[{"type":"text","content":"Data to be presented on December 11, 2025 at 5:00 PM CT","length":55,"tagName":"p"}]}],"tagName":"ul","bulletedList":true,"length":528,"olType":false},{"type":"text","content":"NEW YORK, Dec. 1, 2025 /PRNewswire/ -- Actinium Pharmaceuticals, Inc. (NYSE American: ATNM), a leader in the development of differentiated targeted radiotherapies, today announced compelling preclinical data for ATNM-400, a first-in-class Actinium-225 (AC-225) antibody radioconjugate, in hormone receptor positive (HR+), HER2 positive (HER2+) and triple-negative breast cancer (TNBC) that will be presented at the San Antonio Breast Cancer Symposium (SABCS) being held December 10‑14, 2025 in San Antonio, Texas. The data demonstrates significant anti-tumor activity in breast cancer models resistant to standard-of-care therapies including endocrine therapy tamoxifen and HER2-targeted therapy trastuzumab (Herceptin, Roche) as well as potent tumor growth inhibition in TNBC models. The data highlight ATNM-400's potential to address critical unmet needs in patients who have exhausted treatment options following endocrine therapy or HER2-targeted therapy failure. These data add to ATNM-400's robust preclinical data package that also encompasses metastatic castrate-resistant prostate cancer (mCRPC) and non-small cell lung cancer (NSCLC).","length":1152,"tagName":"p"},{"type":"image","alt":"(PRNewsfoto/Actinium Pharmaceuticals, Inc.)","displaySize":"","headline":null,"caption":"(PRNewsfoto/Actinium Pharmaceuticals, Inc.)","className":"","disableSlideshowImg":false,"size":{"original":{"width":400,"height":97,"url":"https://media.zenfs.com/en/prnewswire.com/eb2937f11974a1...