• Abstracts highlight data pertaining to both Iomab-B and Actimab-A clinical results including the SIERRA Phase 3 trial, dosimetry and machine learning applications for personalized radiotherapy dosing and novel radiotherapy discovery

NEW YORK, May 22, 2023 /PRNewswire/ -- Actinium Pharmaceuticals, Inc. (NYSE AMERICAN: ATNM) (Actinium or the Company), a leader in the development of targeted radiotherapies, today announced that six abstracts have been accepted for oral and poster presentation at the upcoming Society for Nuclear Medicine & Molecular Imaging (SNMMI) 2023 Annual Meeting, which will be held in Chicago, June 24-27, 2023.  These abstracts exhibit the breadth of Actinium's technological and clinical endeavors over the past year that are now culminating in targeted radiotherapies that improve the outcomes of cancer patients.

Details of the SNMMI oral presentation:

Presentation Title: Machine learning applications to optimize dosimetric imaging of I131-apamistamab for bone marrow conditioning in relapsed/refractory acute myeloid leukemia (R/R AML)
Session Type/Title: Oral / New developments in radiopharmaceutical therapy
Date and Time: June 25, 5:00pm – 6:15pm ET

Details of the SNMMI poster presentations:

All posters will be accessible for viewing for the entirety of the conference. The general session is Science Pavilion – Meet the Authors Session: June 26, 5:15pm – 6:15pm

Abstract Title: Relative biological effectiveness of antibody radioconjugates (ARCs): In vitro dosimetric evaluation to streamline pre-clinical decision-making
ID: P86
Track: Oncology, Basic and Translational

Abstract Title: Streamlining personalized dosimetry for I131-apamistamab using a Co-57 sheet source to circumvent the need for radionuclide-specific attenuation correction
ID: P715
Track: Molecular Targeting Probes-Radioactive & Nonradioactive

Abstract Title: Organ-specific dosimetry to estimate potential toxicity thresholds of Actimab-A (lintuzumab-Ac225) used in combination with venetoclax in relapsed/refractory AML
ID: P88
Track: Oncology, Basic and Translational

Abstract Title: Individualized dosing for high-dose targeted radiation of hematopoietic cells with Iomab-B (I131-apamistamab) prior to HCT in relapsed/refractory acute myeloid leukemia (R/R AML): Safety and efficacy results from the pivotal phase 3 SIERRA trial
ID: P685
Track: Oncology Clinical Diagnosis & Therapy

Abstract Title: Administration and radiation safety of high-dose Iomab-B (I131-apamistamab) demonstrated in multiple clinical settings: Experience from the large multicenter phase 3 SIERRA trial for targeted conditioning of patients with relapsed/refractory AML
ID: P730
Track: Oncology Clinical Diagnosis & Therapy

About Actinium

Actinium Pharmaceuticals, Inc. is a clinical-stage biopharmaceutical company developing targeted radiotherapies to deliver cancer-killing radiation with cellular level precision to treat patients with high unmet needs. Actinium's clinical pipeline is led by targeted radiotherapies that are being applied to targeted conditioning, which is intended to selectively deplete a patient's disease or cancer cells and certain immune cells prior to a bone marrow transplant (BMT), gene therapy or adoptive cell therapy, such as CAR-T, to enable engraftment of these transplanted cells with minimal toxicities. Our lead product candidate, Iomab-B (I-131 apamistamab) has been studied in over four hundred patients, including the pivotal Phase 3 Study of Iomab-B in Elderly Relapsed or Refractory Acute Myeloid Leukemia (SIERRA) trial for BMT conditioning. The SIERRA trial was positive with Iomab-B meeting the primary endpoint of durable Complete Remission of 6-months with high statistical significance (p<0.0001). Iomab-B enabled 100% of patients to access a BMT and produced higher rates of post-BMT CR. Iomab-B produced positive results for the secondary endpoints of the SIERRA trial including reducing the probability of an event by 78% resulting in an Event-Free Survival (EFS) Hazard Ratio of 0.22 (p<0.0001), doubled 1-year overall survival and median overall survival. Iomab-ACT, low dose I-131 apamistamab, is being studied as a targeted conditioning agent in a Phase 1 study with a CD19 CAR T-cell Therapy with Memorial Sloan Kettering Cancer Center with NIH funding. Actimab-A, our second most advanced product candidate has been studied in approximately 150 patients with Acute Myeloid Leukemia or AML, including in combination trials with the chemotherapy regimen CLAG-M and with venetoclax, a targeted therapy. Actimab-A or lintuzumab-Ac225 is an Actinium-225 based antibody radiation conjugate targeting CD33, a validated target in AML. Actinium has entered into a Cooperative Research and Development Agreement (CRADA) with the National Cancer Institute (NCI) to develop Actimab-A as a single agent or combination with chemotherapy, targeted agents or immunotherapy in Phase 1, 2 or 3 trials. The NCI will fund clinical trial expenses under the CRADA while Actinium will supply Actimab-A. The NCI is currently accepting proposals for non-clinical and clinical studies with Actimab-A. Actinium is a pioneer and leader in the field of Actinium-225 alpha therapies with an industry leading technology platform comprising over 200 patents and patent applications including methods of producing the radioisotope AC-225. Our technology and expertise have enabled collaborative research partnerships with Astellas Pharma, Inc. for solid tumor theranostics, with AVEO Oncology Inc. to create an Actinium-225 HER3 targeting radiotherapy for solid tumors, and with EpicentRx, Inc. to create targeted radiotherapy combinations with their novel, clinical stage small molecule CD47-SIRPα inhibitor. More information is available on Actinium's website: https://www.actiniumpharma.com/.

Forward-Looking Statements

This press release may contain projections or other "forward-looking statements" within the meaning of the "safe-harbor" provisions of the private securities litigation reform act of 1995 regarding future events or the future financial performance of the Company which the Company undertakes no obligation to update. These statements are based on management's current expectations and are subject to risks and uncertainties that may cause actual results to differ materially from the anticipated or estimated future results, including the risks and uncertainties associated with preliminary study results varying from final results, estimates of potential markets for drugs under development, clinical trials, actions by the FDA and other governmental agencies, regulatory clearances, responses to regulatory matters, the market demand for and acceptance of Actinium's products and services, performance of clinical research organizations and other risks detailed from time to time in Actinium's filings with the Securities and Exchange Commission (the "SEC"), including without limitation its most recent annual report on form 10-K, subsequent quarterly reports on Forms 10-Q and Forms 8-K, each as amended and supplemented from time to time.

Contact:

Matthew Beck
Vice President Investor Relations & Communications
mbeck@actiniumpharma.com
(917) 415-1750

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