- Iomab-B is the first CD45 targeted radiotherapy for
conditioning in development to enable potentially curative bone
marrow transplant and represents an alternative to
chemotherapy-based approaches
- SIERRA achieved durable Complete Remission primary endpoint and
Event-Free Survival secondary endpoint with high statistical
significance
- Iomab-B was well tolerated in the older, heavily pretreated
relapsed/refractory AML patients with active disease enrolled in
the SIERRA trial
- Actinium to seek strategic partner for Iomab-B for further
development in the U.S. following completion of interactions with
FDA for additional head-to-head clinical trial to demonstrate
overall survival benefit
NEW
YORK, Sept. 20, 2024 /PRNewswire/ --
Actinium Pharmaceuticals, Inc. (NYSE AMERICAN: ATNM)
(Actinium or the Company), a leader in the development of Antibody
Radiation Conjugates (ARCs) and other targeted radiotherapies,
today announced the publication of the Phase 3 SIERRA results of
Iomab-B in the peer-reviewed Journal of Clinical Oncology (JCO).
The article, titled, "Randomized Phase III SIERRA Trial of
131I-Apamistamab Before Allogeneic Hematopoietic Cell
Transplantation vs Conventional Care for Relapsed/Refractory Acute
Myeloid Leukemia" and is available online on the ASCO Journal of
Clinical Oncology website HERE.
The Phase 3 SIERRA (Study of Iomab-B in
Elderly Relapsed Refractory AML) trial
was a randomized, multi-center, controlled trial that enrolled 153
patients aged 55 and above with active relapsed or refractory Acute
Myeloid Leukemia (r/r AML), including heavily pre-treated patients
and those with high-risk characteristics such as a TP53 mutation.
The SIERRA trial compared outcomes of patients receiving Iomab-B
(Iodine-131-apamistamab) and a bone marrow transplant (BMT) to
physician's choice of salvage chemotherapy and standard allogeneic
BMT in the control arm.
The SIERRA trial met the primary endpoint of durable Complete
Remission (dCR) of 6-months following initial complete remission
after BMT with high statistical significance (p-value of
<0.0001) with 22% of patients (13/76) achieving dCR in the
Iomab-B arm compared to 0% of patients (0/77) in the control arm. A
significant improvement in Event Free Survival (EFS), a secondary
endpoint of the SIERRA trial with a Hazard Ratio = 0.22 (p-value
<0.0001) was also achieved. SIERRA did not meet the secondary
endpoint of overall survival (OS) on an intent to treat basis
analysis due to the high crossover rate with nearly 60% of control
arm patients receiving Iomab-B followed by a BMT.
The Phase 3 SIERRA results were first presented in a
late-breaker presentation at the Transplantation & Cellular
Therapy (TCT) Tandem Meetings of the American Society for
Transplantation and Cellular Therapy (ASTCT) and the Center for
International Blood & Marrow Transplant Research (CIBMTR) in
February 2023. Since TCT, the results
of the SIERRA trial have been presented in several oral
presentations at leading BMT, hematology, nuclear medicine and
nursing meetings and congresses in the U.S. and EU. Supplemental
analyses of the SIERRA results have shown improved survival
outcomes in patients with a TP53 mutation, which is associated with
poor outcomes, as well as increased 1-and 2-year overall survival
in patients aged 65 and above.
Dr. Sergio Giralt, Deputy
Division Head, Division of Hematological Malignancies and Attending
Physician, Adult BMT Service at the Memorial Sloan Kettering Cancer
Center, and leading SIERRA Trial investigator and corresponding
author, said, "The SIERRA trial was important for the field of
transplant and demonstrated for the first time in a randomized
study that the CD45 antibody-radioconjugate Iomab-B can provide
patients with improved access to a potentially curative
hematopoietic stem cell transplant, and improved outcomes compared
to current chemotherapy-based regimens. Importantly, Iomab-B
demonstrated a statistically significant improvement in key
efficacy endpoints including durable Complete Remission and
event-free survival. The SIERRA trial was conducted as multiple new
therapies gained approval and was designed to address the nuances
and difficulty of treating this patient population including
allowing physician's choice of care in the control arm given the
heterogeneity of treatment across institutions and the crossover
design to provide best patient care. Despite multiple drug
approvals for patients with AML, there remains no curative options
for older patients with relapsed or refractory disease and outcomes
for these patients also remain dismal. My fellow investigators and
I are disappointed that the SIERRA trial will not support the
approval of Iomab-B despite the positive results and significant
unmet medical need of this patient population. However, there is
continued significant interest from the transplant community to
participate in the upcoming phase 3 study with Iomab-B to provide
patients access to this important drug candidate."
On August 05, 2024, Actinium
announced that after concluding both its clinical and Chemistry,
Manufacturing and Controls ("CMC") interactions with the FDA
regarding the BLA pathway for Iomab-B, the FDA determined that
demonstrating an overall survival benefit in a randomized
head-to-head trial is required for a BLA filing, and the SIERRA
trial alone will not be adequate for BLA filing.
Sandesh Seth, Actinium's Chairman
and CEO, stated, "We are excited that the SIERRA results have been
published in the peer-reviewed Journal of Clinical Oncology. We
believe the SIERRA trial was a major advancement for the field of
BMT and targeted radiotherapeutics but most importantly for
patients with relapsed and refractory AML. We look forward to
completing our interactions with the FDA to finalize the specifics
of the additional Phase 3 randomized trial and working to secure a
U.S. partner for Iomab-B. In doing so, we hope to accelerate
Iomab-B reaching patients with high unmet need that can benefit
from a bone marrow transplant."
About Actinium Pharmaceuticals, Inc.
Actinium develops targeted radiotherapies to meaningfully
improve survival for people who have failed existing oncology
therapies. Advanced pipeline candidates Iomab-B, an induction and
conditioning agent prior to bone marrow transplant, and Actimab-A
(National Cancer Institute CRADA pivotal development path), a
therapeutic agent, 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 holds more than 230
patents and patent applications including several patents related
to the manufacture of the isotope Ac-225 in a cyclotron.
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.
Investors:
investorrelations@actiniumpharma.com
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