Actinium Pharmaceuticals, Inc. (delaware) · AMEX:ATNM
Actinium Pharmaceuticals, Inc. (delaware) — Actinium Pharmaceuticals — Technical Presentation (October 2026)
12 slides from Actinium Pharmaceuticals, Inc. (delaware)'s technical presentation, Oct 19, 2026
Slide 1: First-In-Human Phase 1 Study of ATNM-400 in mCRPC
First-In-Human Phase 1 Study of ATNM-400, a Novel HER3-Targeting, Actinium-225 Antibody Radioconjugate, in Metastatic Castration-Resistant Prostate Cancer (mCRPC) G. Cardaci1, A. Singh1, T. Michele2, N. Lenzo3, G. Ghosh3, J. Kim4, S. Heeger4 1GenesisCare Murdoch, Murdoch WA, Australia2, GenesisCare
Slide 2: EANM Disclosure of Interest Statement
EANM Disclosure of Interest Statement 1) All clinical nuclear medicine images and data in the submitted abstract were obtained under EARL PET/CT | PET/MR accreditation. 2) JK and SH are employees of Actinium Pharmaceuticals, Inc. 3) No other co-authors receive support from a pharmaceutical, device,
Slide 3: HER3 is a High-Value Target for Actinium-225 Radiotherapy in Prostate Cancer
HER3 is a High-Value Target for Actinium-225 Radiotherapy in Prostate Cancer HER3 Overexpression is Associated with Poorer Outcomes in HER3 Drives Resistance to HER3 is Ideal for 225Ac-Targeted CRPC ARPIs in mCRPC Radiotherapy for PCa Overexpressed in Earlier progression Shorter overall Clinically V
Slide 4: ATNM-400 is Efficacious Across Varying Levels of PSMA & HER3 Expression
ATNM-400 is Efficacious Across Varying Levels of PSMA & HER3 Expression In vivo efficacy in 22Rv1 prostate cancer cells In vivo efficacy in C4-2 prostate cancer cells In vivo efficacy in DU145 prostate cancer cell (Low PSMA, Moderate HER3) (High PSMA, High HER3) (Negative PSMA, Low HER3) Mean tumor
Slide 5: ATNM-400: A HER3-Targeting Radiotherapy in Prostate Cancer
ATNM-400: A HER3-Targeting Radiotherapy in Prostate Cancer Theranostic Approach • Theranostic approach with Zr-89 for imaging and Ac-225 for therapy being utilized in the Phase 1 dose escalation study in mCRPC o [89Zr]Zr-barecetamab-DFO o [225Ac]Ac-barecetamab-DOTA • HER3-positive lesions (SUV ≥1.5
Slide 6: Study Design
Study Design Key Inclusion & Imaging Assessment Dose Escalation Dose Expansion Exclusion Criteria & Dosimetry N=22-40 N=18 • Confirmed progressive • Theranostic-based patient • ATNM-400 IV q6w, up to 4 • ATNM-400 IV q6w, up to 4 mCRPC selection [89Zr]Zr- cycles cycles • Received at least one barecet
Slide 7: Patient Summary
Patient Summary • Imaging dose (2 ± 0.2 mCi); Treatment dose (1.0 µCi/kg, 0.037 MBq/kg) Pt ATNM-400 ATNM-400 ATNM-400 ATNM-400 Age (yr) Prior Treatments HER3 +* Number (C1D1) (C2D1) (C3D1) (C4D1) ARPI 1 88 Cabazitaxel + √ √ √ √ Carboplatin ARPI Docetaxel 2 79 [177Lu]Lu-PSMA √ √ √ √ Cabazitaxel 3 87
Slide 8: Safety
Safety • No xerostomia • No DLTs observed • No Gr3/4 hematologic AEs observed during DLT window and beyond • No ALT/AST elevation • No Cr elevation • Gr 2 nausea (1 pt) managed with metoclopramide • No injection site or infusion-related reaction
Slide 9: Biodistribution Day 4 post [89Zr]Zr-barecetamab-DFO administration
Biodistribution Day 4 post [89Zr]Zr-barecetamab-DFO administration
Slide 10: [89Zr]Zr-barecetamab-DFO Lesion Uptake
[89Zr]Zr-barecetamab-DFO Lesion Uptake 12 D1 D4 D7 Lesion 10 SUV max SUV max SUV max 8 ROI-1 3.98 11.06 11.97 6 ROI-5 4.64 8.2 10.53 ROI-1 4 ROI-11 ROI-7 3.55 8.5 9.63 ROI-16 2 ROI-11 6.05 7.10 10.74 ROI-5 ROI-7 0 ROI-16 3.32 7.57 6.04 D1 D4 D7
Slide 11: Conclusion
Conclusion • HER3 is a compelling target for alpha therapy in mCRPC • Dose escalation of ATNM-400 has cleared dose level 1 (1 μCi/kg) with no DLTs • No xerostomia and no Gr3/4 hematologic toxicity were observed • ⁸⁹Zr-barecetamab-DFO imaging supports patient selection • PET shows encouraging tumor u
Slide 12: Acknowledgements
Acknowledgements • The Investigators and Actinium Site Location Status Genesis Care Murdoch Perth, Western Australia Enrolling Pharmaceuticals would like to ICON Cancer Centre – Hollywood Perth, Western Australia Enrolling thank all the care teams and Melbourne Theranostic Innovation Centre (MTIC) N
Actinium Pharmaceuticals — Technical Presentation (October 2026) on 6ix