{"success":true,"data":{"pressRelease":{"id":"53634","rtpr_id":"nPn5RH3Zpa","ticker":"ATNM","exchange":"NYSE American","all_tickers":["ATNM"],"title":"Actinium Presents New ATNM-400 Data in KRAS and EGFR Mutant Models at SNMMI 2026 Supporting a Mutation-Agnostic Opportunity In Non-Small Cell Lung Cancer","author":"PR Newswire","published_at":"2026-06-03T12:01:58.078Z","article_body":"Actinium Presents New ATNM-400 Data in KRAS and EGFR Mutant Models at SNMMI 2026 Supporting a Mutation-Agnostic Opportunity In Non-Small Cell Lung Cancer\n\nPR Newswire\n\nNEW YORK, June 3, 2026\n\n * New KRAS-mutant data show ATNM-400 outperformed standard-of-care inhibitors\nsotorasib and adagrasib as a monotherapy. Treatment with these agents\nincreased expression of the ATNM-400 target greater than 3.5x and enhanced\ntheir effect in combination\n \n * Additional data in the EGFR-mutant setting demonstrated powerful synergy with\nosimertinib due to enhanced target expression in treated animals resulting in\ncomplete tumor regression in the combination arm\n \n * The data with EGFR and KRAS mutations which account for approximately 40-50\npercent of all NSCLC cases provide compelling evidence of the potential of\nATNM-400 as a monotherapy or in combination with inhibitory agents against\nthese mutations\n \n * ATNM-400 is a radioconjgate comprising an antibody coupled to Actinium-225\nwhich causes cell death via double stranded DNA breaks independent of cellular\nmechanisms and offers broad potential as a mutation agnostic agent in NSCLC\nwhere its target is expressed in over 90 percent of tumors with greater\nexpression as resistance emerges\nNEW YORK, June 3, 2026 /PRNewswire/ -- Actinium Pharmaceuticals, Inc. (NYSE\nAmerican: ATNM) (Actinium or the Company), a pioneer in the development of\ntargeted radiotherapies, on June 2, 2026, presented new preclinical data on\nATNM-400 in non-small cell lung cancer (NSCLC) at the Society of Nuclear\nMedicine and Molecular Imaging (SNMMI) 2026 Annual Meeting in Los Angeles,\nCalifornia.\n\nThe new KRAS-mutant data, together with a growing body of EGFR-mutant data,\ndemonstrate ATNM-400's activity across the two major mutation driver classes\nin NSCLC and support a distinct strategic opportunity. ATNM-400 can be\ndeveloped as a potential mutation-agnostic backbone for the broader NSCLC\nmarket, alone or in combination with standard-of-care therapies, rather than\nas another mutation-specific drug for a narrow subset.\n\nNSCLC accounts for roughly 85% of the more than two million lung cancer cases\ndiagnosed globally each year, a market more than twice the size of prostate\ncancer. It is also highly heterogeneous: no single mutation dominates, so\ntreatments are fragmented across mutation-specific therapies such as EGFR,\nKRAS, BRAF, ALK and others, each marketed by different companies, each\naddressing only a molecular subset, and each ultimately limited by acquired\nresistance. ATNM-400, Actinium's first-in-class Actinium-225 (Ac-225) antibody\nradioconjugate, is designed to break out of that single-mutation paradigm.\nRather than blocking a specific mutant protein, it delivers a\nhigh-linear-energy-transfer alpha-particle payload that induces dense,\nirreversible double-strand DNA breaks and tumor-cell death independent of a\ntumor's driver mutation or signaling pathway, the mechanistic basis of its\nmutation-agnostic activity.\n\nATNM-400's target antigen, from previously published immunohistochemistry\nstudies, is present in approximately 98% of NSCLC tumors and highly expressed\nin approximately 70% of those tumors. It is conserved across EGFR-, KRAS-, and\nother driver-defined subgroups, and further increased in tumors that have\nbecome resistant to EGFR, KRAS, and immune-checkpoint therapies. In new\nKRAS-mutant studies presented at SNMMI, sotorasib (active ingredient in\nLUMAKRAS(®)/Amgen) and adagrasib (active ingredient in KRAZATI(®)/BMS)\nincreased ATNM-400's target up to 3.5- and 3.8-fold, respectively, and adding\nATNM-400 deepened tumor-cell killing beyond either inhibitor alone. These\nresults demonstrate the same target-expression increasing, synergy-enabling\nbiology shown previously with the EGFR inhibitor osimertinib, which produced\ntumor growth inhibition of 107% when combined with ATNM-400.\n\nThese combination benefits also broaden ATNM-400's commercial opportunity. The\nfranchises it could enhance are substantial; the KRAS inhibitor class in NSCLC\nis projected to exceed $5 billion in peak sales, and the EGFR-mutant segment\nhas peak sales estimates over $15 billion, led by osimertinib (active\ningredient in TAGRISSO(®)/AZ), which generated $7.3 billion in 2025. This\npositions ATNM-400 to participate in these established markets by enhancing\nthe standard of care, while also reaching the broader NSCLC population beyond\nany single mutation.\n\nSandesh Seth, Actinium's Chairman and CEO, said, \"Today's data further\nstrengthen our conviction that ATNM-400 represents a fundamentally different\napproach to treating NSCLC solid tumors. While most targeted therapies are\ndesigned for a single mutation-defined patient population, ATNM-400 combines\nthe mutation-independent cell-killing power of Actinium-225 with a target that\nis broadly expressed across tumors and becomes even more abundant as\nresistance emerges. The consistency of activity we have now demonstrated\nacross both EGFR- and KRAS-driven NSCLC supports our vision for ATNM-400 as a\npotential mutation-agnostic backbone therapy that can be used alone or in\ncombination across large patient populations. We believe this opportunity\ncould extend beyond lung cancer and may position ATNM-400 as a foundational\ntherapy across multiple solid tumor indications.\"\n\nHighlights from the SNMMI 2026 Poster Presentation\n\nPoster Titled: ATNM-400: A First-in-Class Actinium-225 Antibody Radioconjugate\nDemonstrating Durable, Mutation-Agnostic Anti-Tumor Activity in Non-Small Cell\nLung Cancer Models\n\nNew data demonstrated ATNM-400's potential as a mutation-agnostic antibody\nradioconjugate therapy for NSCLC:\n\n * Across a panel of four lung cancer cell lines spanning EGFR- and KRAS-driver\nmutations, ATNM-400 bound and was internalized specifically by the three\ntarget-positive lines (NCI-H1975, NCI-H358 and Calu-3) but not by the\ntarget-negative line (A549), confirming that its activity is driven by target\nexpression rather than by any particular mutation.\n(https://mma.prnewswire.com/media/2993773/Actinium_Pharmaceuticals_Inc_1.html)\n\n * In a KRAS G12C model (NCI-H358), PET imaging of radiolabeled ATNM-400 showed\nthe drug concentrating in the tumor with low uptake in healthy tissue,\nvisually confirming that it reaches its target in a living animal and delivers\nits alpha payload where intended while largely sparing normal organs.\n(https://mma.prnewswire.com/media/2993772/Actinium_Pharmaceuticals_Inc_2.html)\n\n * In a KRAS G13D model (Calu-3), a single dose of ATNM-400 drove tumor\nregression (124% and 135% inhibition at two dose levels), indicating marked\nantitumor potencywith full body-weight recovery. Deep responses from one dose\nwith a clean tolerability profile point to a wide therapeutic window and\ndosing flexibility, favorable attributes for clinical translation.\n(https://mma.prnewswire.com/media/2993771/Actinium_Pharmaceuticals_Inc_3.html)\n\n * Treatment with both approved KRAS inhibitors (sotorasib and adagrasib) raised\nATNM-400's target expression dose-dependently—up to roughly 3.5- to\n3.8-fold—reaching statistical significance at every dose (p < 0.0001).\nThe effect occurred with both agents, indicating a class-wide consequence of\nKRAS G12C inhibition that builds a rationale for combining ATNM-400 with these\ntherapies.\n(https://mma.prnewswire.com/media/2993770/Actinium_Pharmaceuticals_Inc_4.html)\n\n * ATNM-400 plus sotorasib or adagrasib decreased cancer-cell viability beyond\neither inhibitor alone. The data demonstrate that ATNM-400 has development\npotential not only as a monotherapy but also in combination with these leading\nKRAS therapies and possibly the entire KRAS-mutant class.\n(https://mma.prnewswire.com/media/2993769/Actinium_Pharmaceuticals_Inc_5.html)\n\n * In an EGFR-mutant model (NCI-H1975), ATNM-400 monotherapy achieved 75% tumor\ngrowth inhibition versus 40% for osimertinib; combined with osimertinib it\nreached 107% inhibition with complete cures in 100% of mice. Osimertinib\nraised target expression, providing a clear rationale for the combination.\n(https://mma.prnewswire.com/media/2993768/Actinium_Pharmaceuticals_Inc_6.html)\n\nAbout Actinium Pharmaceuticals, Inc.\n\nActinium is a pioneer in targeted radiotherapies designed to improve outcomes\nfor patients with cancer. The company employs a biology-driven approach to\ndevelop differentiated radiopharmaceuticals for solid tumors and hematologic\nmalignancies. Its mission is to transform cancer treatment through innovative\nradioconjugates that maximize therapeutic efficacy while minimizing toxicity\nto healthy tissue by combining expertise in tumor biology, translational\nmedicine, and radiochemistry. Since inception, Actinium has focused on\ndeveloping innovative radiotherapies. Its pipeline reflects this strategy\nacross three areas: (1) solid tumor therapeutics including ATNM-400 and\nActimab-A with pan-tumor potential; (2) Actimab-A as a therapeutic backbone\nfor acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) in\ncollaboration with the National Cancer Institute (NCI); and (3) targeted\nconditioning agents including Iomab-B for bone marrow transplant and Iomab-ACT\nfor cell and gene therapy conditioning. ATNM-400 targets a novel antigen\ndistinct from PSMA and has demonstrated preclinical activity across metastatic\ncastration-resistant prostate cancer (mCRPC), non-small cell lung cancer\n(NSCLC), and breast cancer. Actimab-A has shown improved survival in\nrelapsed/refractory AML with CLAG-M and is advancing toward a Phase 2/3 trial,\nwith additional development ongoing through a CRADA with the NCI. Actinium is\nalso advancing preclinical solid tumor programs and holds approximately 250\npatents and patent applications, including intellectual property related to\ncyclotron-based production of Ac-225. For more information, please visit\nwww.actiniumpharma.com\n(https://edge.prnewswire.com/c/link/?t=0&l=en&o=4702812-1&h=215138406&u=https%3A%2F%2Fwww.actiniumpharma.com%2F&a=www.actiniumpharma.com)\n.\n\nForward-Looking Statements\n\nThis press release may contain projections or other \"forward-looking\nstatements\" within the meaning of the \"safe-harbor\" provisions of the private\nsecurities litigation reform act of 1995 regarding future events or the future\nfinancial performance of the Company which the Company undertakes no\nobligation to update. These statements, including statements as related to\nregaining compliance with the rules of the NYSE American and submission of a\ncompliance plan, are based on management's current expectations and are\nsubject to risks and uncertainties that may cause actual results to differ\nmaterially from the anticipated or estimated future results, including the\nrisks and uncertainties associated with preliminary study results varying from\nfinal results, estimates of potential markets for drugs under development,\nclinical trials, actions by the FDA and other governmental agencies,\nregulatory clearances, responses to regulatory matters, the market demand for\nand acceptance of Actinium's products and services, performance of clinical\nresearch organizations and other risks detailed from time to time in\nActinium's filings with the Securities and Exchange Commission (the \"SEC\"),\nincluding without limitation its most recent annual report on Form 10-K,\nsubsequent quarterly reports on Forms 10-Q and Forms 8-K, each as amended and\nsupplemented from time to time.\n\nInvestors: investorrelations@actiniumpharma.com\n(mailto:investorrelations@actiniumpharma.com)\n\n(https://mma.prnewswire.com/media/730678/Actinium_Pharmaceuticals_Logo.html)\n\nView original content to download\nmultimedia:https://www.prnewswire.com/news-releases/actinium-presents-new-atnm-400-data-in-kras-and-egfr-mutant-models-at-snmmi-2026-supporting-a-mutation-agnostic-opportunity-in-non-small-cell-lung-cancer-302789401.html\n(https://www.prnewswire.com/news-releases/actinium-presents-new-atnm-400-data-in-kras-and-egfr-mutant-models-at-snmmi-2026-supporting-a-mutation-agnostic-opportunity-in-non-small-cell-lung-cancer-302789401.html)\n\nSOURCE Actinium Pharmaceuticals, Inc.\n\n\n\nPhoto: \nhttps://mma.prnewswire.com/media/2993773/Actinium_Pharmaceuticals_Inc_1.jpg\nhttps://mma.prnewswire.com/media/2993772/Actinium_Pharmaceuticals_Inc_2.jpg\nhttps://mma.prnewswire.com/media/2993771/Actinium_Pharmaceuticals_Inc_3.jpg\nhttps://mma.prnewswire.com/media/2993770/Actinium_Pharmaceuticals_Inc_4.jpg\nhttps://mma.prnewswire.com/media/2993769/Actinium_Pharmaceuticals_Inc_5.jpg\nhttps://mma.prnewswire.com/media/2993768/Actinium_Pharmaceuticals_Inc_6.jpg\nhttps://mma.prnewswire.com/media/730678/Actinium_Pharmaceuticals_Logo.jpg\n\nCopyright (c) 2026 PR Newswire Association,LLC. All Rights Reserved.","article_body_html":"","raw_payload":{"data":{"id":"nPn5RH3Zpa","title":"Actinium Presents New ATNM-400 Data in KRAS and EGFR Mutant Models at SNMMI 2026 Supporting a Mutation-Agnostic Opportunity In Non-Small Cell Lung Cancer","author":"PR Newswire","ticker":"ATNM","created":"2026-06-03T12:01:58.078Z","tickers":["ATNM"],"exchange":"NYSE American","article_body":"Actinium Presents New ATNM-400 Data in KRAS and EGFR Mutant Models at SNMMI 2026 Supporting a Mutation-Agnostic Opportunity In Non-Small Cell Lung Cancer\n\nPR Newswire\n\nNEW YORK, June 3, 2026\n\n * New KRAS-mutant data show ATNM-400 outperformed standard-of-care inhibitors\nsotorasib and adagrasib as a monotherapy. Treatment with these agents\nincreased expression of the ATNM-400 target greater than 3.5x and enhanced\ntheir effect in combination\n \n * Additional data in the EGFR-mutant setting demonstrated powerful synergy with\nosimertinib due to enhanced target expression in treated animals resulting in\ncomplete tumor regression in the combination arm\n \n * The data with EGFR and KRAS mutations which account for approximately 40-50\npercent of all NSCLC cases provide compelling evidence of the potential of\nATNM-400 as a monotherapy or in combination with inhibitory agents against\nthese mutations\n \n * ATNM-400 is a radioconjgate comprising an antibody coupled to Actinium-225\nwhich causes cell death via double stranded DNA breaks independent of cellular\nmechanisms and offers broad potential as a mutation agnostic agent in NSCLC\nwhere its target is expressed in over 90 percent of tumors with greater\nexpression as resistance emerges\nNEW YORK, June 3, 2026 /PRNewswire/ -- Actinium Pharmaceuticals, Inc. (NYSE\nAmerican: ATNM) (Actinium or the Company), a pioneer in the development of\ntargeted radiotherapies, on June 2, 2026, presented new preclinical data on\nATNM-400 in non-small cell lung cancer (NSCLC) at the Society of Nuclear\nMedicine and Molecular Imaging (SNMMI) 2026 Annual Meeting in Los Angeles,\nCalifornia.\n\nThe new KRAS-mutant data, together with a growing body of EGFR-mutant data,\ndemonstrate ATNM-400's activity across the two major mutation driver classes\nin NSCLC and support a distinct strategic opportunity. ATNM-400 can be\ndeveloped as a potential mutation-agnostic backbone for the broader NSCLC\nmarket, alone or in combination with standard-of-care therapies, rather than\nas another mutation-specific drug for a narrow subset.\n\nNSCLC accounts for roughly 85% of the more than two million lung cancer cases\ndiagnosed globally each year, a market more than twice the size of prostate\ncancer. It is also highly heterogeneous: no single mutation dominates, so\ntreatments are fragmented across mutation-specific therapies such as EGFR,\nKRAS, BRAF, ALK and others, each marketed by different companies, each\naddressing only a molecular subset, and each ultimately limited by acquired\nresistance. ATNM-400, Actinium's first-in-class Actinium-225 (Ac-225) antibody\nradioconjugate, is designed to break out of that single-mutation paradigm.\nRather than blocking a specific mutant protein, it delivers a\nhigh-linear-energy-transfer alpha-particle payload that induces dense,\nirreversible double-strand DNA breaks and tumor-cell death independent of a\ntumor's driver mutation or signaling pathway, the mechanistic basis of its\nmutation-agnostic activity.\n\nATNM-400's target antigen, from previously published immunohistochemistry\nstudies, is present in approximately 98% of NSCLC tumors and highly expressed\nin approximately 70% of those tumors. It is conserved across EGFR-, KRAS-, and\nother driver-defined subgroups, and further increased in tumors that have\nbecome resistant to EGFR, KRAS, and immune-checkpoint therapies. In new\nKRAS-mutant studies presented at SNMMI, sotorasib (active ingredient in\nLUMAKRAS(®)/Amgen) and adagrasib (active ingredient in KRAZATI(®)/BMS)\nincreased ATNM-400's target up to 3.5- and 3.8-fold, respectively, and adding\nATNM-400 deepened tumor-cell killing beyond either inhibitor alone. These\nresults demonstrate the same target-expression increasing, synergy-enabling\nbiology shown previously with the EGFR inhibitor osimertinib, which produced\ntumor growth inhibition of 107% when combined with ATNM-400.\n\nThese combination benefits also broaden ATNM-400's commercial opportunity. The\nfranchises it could enhance are substantial; the KRAS inhibitor class in NSCLC\nis projected to exceed $5 billion in peak sales, and the EGFR-mutant segment\nhas peak sales estimates over $15 billion, led by osimertinib (active\ningredient in TAGRISSO(®)/AZ), which generated $7.3 billion in 2025. This\npositions ATNM-400 to participate in these established markets by enhancing\nthe standard of care, while also reaching the broader NSCLC population beyond\nany single mutation.\n\nSandesh Seth, Actinium's Chairman and CEO, said, \"Today's data further\nstrengthen our conviction that ATNM-400 represents a fundamentally different\napproach to treating NSCLC solid tumors. While most targeted therapies are\ndesigned for a single mutation-defined patient population, ATNM-400 combines\nthe mutation-independent cell-killing power of Actinium-225 with a target that\nis broadly expressed across tumors and becomes even more abundant as\nresistance emerges. The consistency of activity we have now demonstrated\nacross both EGFR- and KRAS-driven NSCLC supports our vision for ATNM-400 as a\npotential mutation-agnostic backbone therapy that can be used alone or in\ncombination across large patient populations. We believe this opportunity\ncould extend beyond lung cancer and may position ATNM-400 as a foundational\ntherapy across multiple solid tumor indications.\"\n\nHighlights from the SNMMI 2026 Poster Presentation\n\nPoster Titled: ATNM-400: A First-in-Class Actinium-225 Antibody Radioconjugate\nDemonstrating Durable, Mutation-Agnostic Anti-Tumor Activity in Non-Small Cell\nLung Cancer Models\n\nNew data demonstrated ATNM-400's potential as a mutation-agnostic antibody\nradioconjugate therapy for NSCLC:\n\n * Across a panel of four lung cancer cell lines spanning EGFR- and KRAS-driver\nmutations, ATNM-400 bound and was internalized specifically by the three\ntarget-positive lines (NCI-H1975, NCI-H358 and Calu-3) but not by the\ntarget-negative line (A549), confirming that its activity is driven by target\nexpression rather than by any particular mutation.\n(https://mma.prnewswire.com/media/2993773/Actinium_Pharmaceuticals_Inc_1.html)\n\n * In a KRAS G12C model (NCI-H358), PET imaging of radiolabeled ATNM-400 showed\nthe drug concentrating in the tumor with low uptake in healthy tissue,\nvisually confirming that it reaches its target in a living animal and delivers\nits alpha payload where intended while largely sparing normal organs.\n(https://mma.prnewswire.com/media/2993772/Actinium_Pharmaceuticals_Inc_2.html)\n\n * In a KRAS G13D model (Calu-3), a single dose of ATNM-400 drove tumor\nregression (124% and 135% inhibition at two dose levels), indicating marked\nantitumor potencywith full body-weight recovery. Deep responses from one dose\nwith a clean tolerability profile point to a wide therapeutic window and\ndosing flexibility, favorable attributes for clinical translation.\n(https://mma.prnewswire.com/media/2993771/Actinium_Pharmaceuticals_Inc_3.html)\n\n * Treatment with both approved KRAS inhibitors (sotorasib and adagrasib) raised\nATNM-400's target expression dose-dependently—up to roughly 3.5- to\n3.8-fold—reaching statistical significance at every dose (p < 0.0001).\nThe effect occurred with both agents, indicating a class-wide consequence of\nKRAS G12C inhibition that builds a rationale for combining ATNM-400 with these\ntherapies.\n(https://mma.prnewswire.com/media/2993770/Actinium_Pharmaceuticals_Inc_4.html)\n\n * ATNM-400 plus sotorasib or adagrasib decreased cancer-cell viability beyond\neither inhibitor alone. The data demonstrate that ATNM-400 has development\npotential not only as a monotherapy but also in combination with these leading\nKRAS therapies and possibly the entire KRAS-mutant class.\n(https://mma.prnewswire.com/media/2993769/Actinium_Pharmaceuticals_Inc_5.html)\n\n * In an EGFR-mutant model (NCI-H1975), ATNM-400 monotherapy achieved 75% tumor\ngrowth inhibition versus 40% for osimertinib; combined with osimertinib it\nreached 107% inhibition with complete cures in 100% of mice. Osimertinib\nraised target expression, providing a clear rationale for the combination.\n(https://mma.prnewswire.com/media/2993768/Actinium_Pharmaceuticals_Inc_6.html)\n\nAbout Actinium Pharmaceuticals, Inc.\n\nActinium is a pioneer in targeted radiotherapies designed to improve outcomes\nfor patients with cancer. The company employs a biology-driven approach to\ndevelop differentiated radiopharmaceuticals for solid tumors and hematologic\nmalignancies. Its mission is to transform cancer treatment through innovative\nradioconjugates that maximize therapeutic efficacy while minimizing toxicity\nto healthy tissue by combining expertise in tumor biology, translational\nmedicine, and radiochemistry. Since inception, Actinium has focused on\ndeveloping innovative radiotherapies. Its pipeline reflects this strategy\nacross three areas: (1) solid tumor therapeutics including ATNM-400 and\nActimab-A with pan-tumor potential; (2) Actimab-A as a therapeutic backbone\nfor acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) in\ncollaboration with the National Cancer Institute (NCI); and (3) targeted\nconditioning agents including Iomab-B for bone marrow transplant and Iomab-ACT\nfor cell and gene therapy conditioning. ATNM-400 targets a novel antigen\ndistinct from PSMA and has demonstrated preclinical activity across metastatic\ncastration-resistant prostate cancer (mCRPC), non-small cell lung cancer\n(NSCLC), and breast cancer. Actimab-A has shown improved survival in\nrelapsed/refractory AML with CLAG-M and is advancing toward a Phase 2/3 trial,\nwith additional development ongoing through a CRADA with the NCI. Actinium is\nalso advancing preclinical solid tumor programs and holds approximately 250\npatents and patent applications, including intellectual property related to\ncyclotron-based production of Ac-225. For more information, please visit\nwww.actiniumpharma.com\n(https://edge.prnewswire.com/c/link/?t=0&l=en&o=4702812-1&h=215138406&u=https%3A%2F%2Fwww.actiniumpharma.com%2F&a=www.actiniumpharma.com)\n.\n\nForward-Looking Statements\n\nThis press release may contain projections or other \"forward-looking\nstatements\" within the meaning of the \"safe-harbor\" provisions of the private\nsecurities litigation reform act of 1995 regarding future events or the future\nfinancial performance of the Company which the Company undertakes no\nobligation to update. These statements, including statements as related to\nregaining compliance with the rules of the NYSE American and submission of a\ncompliance plan, are based on management's current expectations and are\nsubject to risks and uncertainties that may cause actual results to differ\nmaterially from the anticipated or estimated future results, including the\nrisks and uncertainties associated with preliminary study results varying from\nfinal results, estimates of potential markets for drugs under development,\nclinical trials, actions by the FDA and other governmental agencies,\nregulatory clearances, responses to regulatory matters, the market demand for\nand acceptance of Actinium's products and services, performance of clinical\nresearch organizations and other risks detailed from time to time in\nActinium's filings with the Securities and Exchange Commission (the \"SEC\"),\nincluding without limitation its most recent annual report on Form 10-K,\nsubsequent quarterly reports on Forms 10-Q and Forms 8-K, each as amended and\nsupplemented from time to time.\n\nInvestors: investorrelations@actiniumpharma.com\n(mailto:investorrelations@actiniumpharma.com)\n\n(https://mma.prnewswire.com/media/730678/Actinium_Pharmaceuticals_Logo.html)\n\nView original content to download\nmultimedia:https://www.prnewswire.com/news-releases/actinium-presents-new-atnm-400-data-in-kras-and-egfr-mutant-models-at-snmmi-2026-supporting-a-mutation-agnostic-opportunity-in-non-small-cell-lung-cancer-302789401.html\n(https://www.prnewswire.com/news-releases/actinium-presents-new-atnm-400-data-in-kras-and-egfr-mutant-models-at-snmmi-2026-supporting-a-mutation-agnostic-opportunity-in-non-small-cell-lung-cancer-302789401.html)\n\nSOURCE Actinium Pharmaceuticals, Inc.\n\n\n\nPhoto: \nhttps://mma.prnewswire.com/media/2993773/Actinium_Pharmaceuticals_Inc_1.jpg\nhttps://mma.prnewswire.com/media/2993772/Actinium_Pharmaceuticals_Inc_2.jpg\nhttps://mma.prnewswire.com/media/2993771/Actinium_Pharmaceuticals_Inc_3.jpg\nhttps://mma.prnewswire.com/media/2993770/Actinium_Pharmaceuticals_Inc_4.jpg\nhttps://mma.prnewswire.com/media/2993769/Actinium_Pharmaceuticals_Inc_5.jpg\nhttps://mma.prnewswire.com/media/2993768/Actinium_Pharmaceuticals_Inc_6.jpg\nhttps://mma.prnewswire.com/media/730678/Actinium_Pharmaceuticals_Logo.jpg\n\nCopyright (c) 2026 PR Newswire Association,LLC. All Rights Reserved."},"type":"article","timestamp":"2026-06-03T12:01:58.190295202Z","server_sent_at_ms":1780488118190},"received_at":"2026-06-03T12:01:58.254Z","source_url":"https://www.prnewswire.com/news-releases/actinium-presents-new-atnm-400-data-in-kras-and-egfr-mutant-models-at-snmmi-2026-supporting-a-mutation-agnostic-opportunity-in-non-small-cell-lung-cancer-302789401.html"},"analysis":{"id":"43069","press_release_id":"53634","analysis_json":{"industry":{"label":"Biotechnology","sector":"Health Care"},"redFlags":[],"eventType":"clinical_trial","narrative":"Actinium presented preclinical data for ATNM-400 at SNMMI 2026, showing potent activity in both KRAS and EGFR mutant non-small cell lung cancer models.\n\nIn KRAS models, ATNM-400 outperformed standard-of-care inhibitors sotorasib and adagrasib as a monotherapy, and combination therapy showed enhanced tumor cell killing due to increased target expression.\n\nIn EGFR models, combining ATNM-400 with osimertinib resulted in 107% tumor growth inhibition and complete cures in all mice, supporting a mutation-agnostic development strategy.","sentiment":"bullish","agentHooks":{"shouldPost":true,"suggestedAngle":"Preclinical data supports ATNM-400 as a mutation-agnostic backbone in NSCLC, potentially expanding TAM beyond specific mutation subsets."},"keyFigures":{"drugName":"ATNM-400","customDimensions":{"nsclc_market_share":"85%","tagrisso_2025_sales":"$7.3 billion","egfr_mutant_peak_sales":"$15 billion","target_prevalence_nsclc":"98%","kras_inhibitor_peak_sales":"$5 billion","tumor_regression_kras_mono":"124% to 135%","target_high_expression_nsclc":"70%","target_expression_increase_kras":"3.5x to 3.8x","tumor_growth_inhibition_egfr_mono":"75%","tumor_growth_inhibition_egfr_combo":"107%","tumor_growth_inhibition_osimertinib_mono":"40%"}},"quotedText":"Today's data further strengthen our conviction that ATNM-400 represents a fundamentally different approach to treating NSCLC solid tumors.","namedEntities":{"people":[{"name":"Sandesh Seth","role":"Chairman and CEO"}],"products":["ATNM-400","sotorasib","LUMAKRAS","adagrasib","KRAZATI","osimertinib","TAGRISSO","Actimab-A","Iomab-B","Iomab-ACT"],"companies":[{"name":"Actinium Pharmaceuticals, Inc.","ticker":"ATNM","relationship":"filer"},{"name":"Amgen","ticker":"AMGN","relationship":"competitor"},{"name":"BMS","ticker":"BMY","relationship":"competitor"},{"name":"AZ","ticker":"AZN","relationship":"competitor"},{"name":"National Cancer Institute","relationship":"partner"}],"dollarAmounts":[{"amount":"$5 billion","context":"projected peak sales for KRAS inhibitor class in NSCLC"},{"amount":"$15 billion","context":"peak sales estimates for EGFR-mutant segment"},{"amount":"$7.3 billion","context":"TAGRISSO sales in 2025"}]},"materialImpact":{"score":3,"reasoning":"Positive preclinical data presented at a major conference (SNMMI) supporting a mutation-agnostic strategy for ATNM-400 in NSCLC. While promising for de-risking the asset and expanding the addressable market, this is preclinical data, not a clinical readout or regulatory decision, limiting the immediate material impact compared to Phase 2/3 results."},"tickerRelevance":{"others":[{"ticker":"AMGN","relevance":"competitor"},{"ticker":"BMY","relevance":"competitor"},{"ticker":"AZN","relevance":"competitor"}],"primary":"ATNM"},"globalImportance":35,"audienceRelevance":25,"eventTypeSecondary":[],"importanceComponents":{"tickerTier":"small-cap","eventGravity":"preclinical_data","sectorWeight":"high","householdBrandBoost":0,"marketCapAdjustment":"neutral","retailFavoriteBoost":0}},"event_type":"clinical_trial","event_type_secondary":null,"sentiment":"bullish","material_impact_score":3,"narrative":"Actinium presented preclinical data for ATNM-400 at SNMMI 2026, showing potent activity in both KRAS and EGFR mutant non-small cell lung cancer models.\n\nIn KRAS models, ATNM-400 outperformed standard-of-care inhibitors sotorasib and adagrasib as a monotherapy, and combination therapy showed enhanced tumor cell killing due to increased target expression.\n\nIn EGFR models, combining ATNM-400 with osimertinib resulted in 107% tumor growth inhibition and complete cures in all mice, supporting a mutation-agnostic development strategy.","key_figures":{"drugName":"ATNM-400","customDimensions":{"nsclc_market_share":"85%","tagrisso_2025_sales":"$7.3 billion","egfr_mutant_peak_sales":"$15 billion","target_prevalence_nsclc":"98%","kras_inhibitor_peak_sales":"$5 billion","tumor_regression_kras_mono":"124% to 135%","target_high_expression_nsclc":"70%","target_expression_increase_kras":"3.5x to 3.8x","tumor_growth_inhibition_egfr_mono":"75%","tumor_growth_inhibition_egfr_combo":"107%","tumor_growth_inhibition_osimertinib_mono":"40%"}},"named_entities":{"people":[{"name":"Sandesh Seth","role":"Chairman and CEO"}],"products":["ATNM-400","sotorasib","LUMAKRAS","adagrasib","KRAZATI","osimertinib","TAGRISSO","Actimab-A","Iomab-B","Iomab-ACT"],"companies":[{"name":"Actinium Pharmaceuticals, Inc.","ticker":"ATNM","relationship":"filer"},{"name":"Amgen","ticker":"AMGN","relationship":"competitor"},{"name":"BMS","ticker":"BMY","relationship":"competitor"},{"name":"AZ","ticker":"AZN","relationship":"competitor"},{"name":"National Cancer Institute","relationship":"partner"}],"dollarAmounts":[{"amount":"$5 billion","context":"projected peak sales for KRAS inhibitor class in NSCLC"},{"amount":"$15 billion","context":"peak sales estimates for EGFR-mutant segment"},{"amount":"$7.3 billion","context":"TAGRISSO sales in 2025"}]},"model_name":"qwen3_6_27b_awq","prompt_hash":"sha256:727b4b9429a443af","schema_hash":"sha256:05005c02d9cffac9","created_at":"2026-06-04T06:00:40.784Z","global_importance":35,"audience_relevance":25,"importance_components":{"tickerTier":"small-cap","eventGravity":"preclinical_data","sectorWeight":"high","householdBrandBoost":0,"marketCapAdjustment":"neutral","retailFavoriteBoost":0}},"durationMs":null,"modelName":"george-droid-qwen-72b"}}