- Actimab-A can target CD33 positive immune suppressing myeloid
derived suppressor cells and restore T cell proliferation and
effector response
- Solid tumor MDSC infiltration and uptake of Actimab-A confirmed
by SPECT/CT imaging in a humanized non-small cell lung cancer
model
NEW
YORK, Nov. 6, 2023 /PRNewswire/ -- Actinium
Pharmaceuticals, Inc. (NYSE AMERICAN: ATNM) (Actinium or the
Company), a leader in the development of targeted radiotherapies,
today announced data was presented at Society of Immunotherapy of
Cancer (SITC) 38th Annual Meeting on Saturday, November 4, 2023, further
supporting Actimab-A, the Company's clinical stage targeted
radiotherapeutic comprised of the CD33 targeting antibody
lintuzumab and the Actinium-225 (Ac-225) alpha-particle emitting
payload.
The poster highlighted Actimab-A's ability to target and deplete
myeloid-derived suppressor cells (MDSCs), which uniformly express
CD33. MDSCs are a cell population of interest as they remodel the
tumor environment and promote immune evasion. Actinium believes
Actimab-A has the potential to be used in combination with
immunotherapy, including immune checkpoint inhibitors, to enhance
antitumor immunity via targeted MDSC depletion. Supportive data
from the SITC presentation includes:
- Actimab-A reduced cancer patient-derived MDSCs in a
dose-dependent manner ex vivo and decreased MDSC viability
approximately two-fold greater than a non-radiolabeled CD33
antibody
- MDSC suppression of activated T cell proliferation and cytokine
effector function ex vivo was restored following treatment with
Actimab-A
- Actimab-A significantly depleted MDSCs in peripheral blood of
tumor-bearing humanized mice compared to non-radiolabeled CD33
antibody in vivo
- SPECT/CT imaging confirmed uptake of lintuzumab in humanized
mice at the sites of non-small cell lung cancer tumor indicating
enrichment of CD33+ MDSCs in the tumor microenvironment
Sandesh Seth, Actinium's Chairman
and CEO, commented, "These data further increase our enthusiasm for
Actimab-A's potential in solid tumor indications. Immunotherapy has
had a profound impact on patient outcomes across multiple solid
tumor indications, however, there are still several indications
with high unmet needs and significant room to further improve
patient outcomes. By depleting MDSCs in a targeted manner, we are
excited by the prospect of Actimab-A synergizing with immunotherapy
to enhance antitumor immunity. We look forward to continuing to
advance this initiative in continuing our goal to address high
unmet patient needs with our targeted radiotherapeutics."
About Actinium
Actinium develops targeted radiotherapies to meaningfully
improve survival for people who have failed existing oncology
therapies. Advanced pipeline candidates Iomab-B (pre-BLA), an
induction and conditioning agent prior to bone marrow transplant,
and Actimab-A (National Cancer Institute CRADA pivotal development
path), a therapeutic, have demonstrated potential to extend
survival outcomes for people with relapsed and refractory acute
myeloid leukemia. Actinium plans to advance Iomab-B for other
blood cancers and next generation conditioning candidate Iomab-ACT
to improve cell and gene therapy outcomes. Actinium's
technology platform is the basis for collaborations with Astellas
Pharma and AVEO Oncology/LG Chem Life Sciences for solid tumors.
Actinium holds more than 220 patents and patent applications.
For more information, please visit:
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:
investorrelation@actiniumpharma.com
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SOURCE Actinium Pharmaceuticals, Inc.