NEW YORK, Dec. 3, 2018 /PRNewswire/ -- Actinium
Pharmaceuticals, Inc. (NYSE AMERICAN: ATNM) ("Actinium"
or "the Company"), announced today that updated data from its Phase
2 trial of Actimab-A was highlighted in a poster presentation at
the 60th American Society of Hematology (ASH) Annual
Meeting. The Actimab-A Phase 2 trial studied the ARC or
Antibody Radiation Conjugate Actinium-225 – lintuzumab, which
delivers potent alpha particle radiation to CD33 expressing cells,
in patients with untreated AML over the age of 60 that are unfit
for induction chemotherapy. Patients received fractionated
doses of Ac-225 – lintuzumab on days 1 and day 8. The poster
presented at ASH highlighted data from a second cohort of 27
patients that received 1.5 µCi/kg/fraction.
Dr. Mark Berger, Actinium's Chief
Medical Officer said, "In this difficult to treat patient
population, we are pleased to have observed this level of
single-agent activity from Actimab-A with the benefit of minimal
extramedullary toxicities. These results strongly support continued
development and we have prioritized highly attractive areas that
can leverage the strengths of our ARC approach. A major
initiative is our Actimab-MDS trial where we have a clear pathway
to a pivotal trial established with the FDA for high-risk patients
with myelodysplastic syndromes. Another exciting
opportunity is via combination trials with agents like venetoclax
in the relapsed, refractory AML setting where the apparent synergy
of mechanisms can translate to a therapeutic advantage. In
addition, we are pursuing other highly-differentiated opportunities
for Actimab-A as a single-agent in patients with high unmet needs
where the extremely high-potency of an ARC can be used safely at
low doses. An example is our novel trial in AML patients with
minimal residual disease post-remission."
Overall response rate in this dosing cohort was 22% (6/27) with
3 CRps and 3 CRis. Among responding patients, 2 had adverse
cytogenetics and 1 had previous MDS. This data is in addition to
previously reported data from 13 patients that were treated at an
original dose cohort of 2.0 µCi/kg/fraction where a 69% overall
response rate was reported. The dose was lowered to 1.5
µCi/kg/fraction due to myelosuppression lasting longer than 6
weeks, which resulted in a reduction in the incidence of prolonged
thrombocytopenia from 46% to 30%.
The median age of patients in this cohort of the Phase 2 trial
was 75 (60 -87) with 81% of patients having ECOG performance status
of 1 (13/27) or 2 (9/27). Although patients had untreated
acute myeloid leukemia (AML), 52% (14/27) of patients had prior
hematologic disease with 79% (11/14) having myelodysplastic
syndrome (MDS), 14% (2/14) having chromic myelomonocytic leukemia
(CMML) and 7% (1/14) having myelofibrosis. A majority of patients
had unfavorable cytogenetics with 56% (15/27) having
intermediate-risk and 26% (7/27) having high-risk cytogenetics. In
addition, patients were evaluated for CD33 splicing polymorphism
and responses occurred irrespective of cytogenetic risk category or
splicing genotype.
Actinium also highlighted that preliminary preclinical data from
its Iomab-ACT program was highlighted in the ASH supplemental
edition of blood. Actinium's preclinical studies showed a
considerable reduction in both lymphocyte and myeloid cell counts,
inclusive of immune suppressive regulatory T cells and myeloid
derived suppressor cells. Further, the cytoreduction by CD45-RIT
was shown to induce the expression of immune homeostatic cytokines
including IL-15.The abstract can be accessed he
http://www.bloodjournal.org/content/132/Suppl_1/5682.
Sandesh Seth, Actinium's Chairman
and CEO said, "Given the recent and increasing competition in AML,
we believe the future development pathways selected by our team
strategically differentiate Actinium's CD33 program in a manner
that can maximize value creation. We have done this by
focusing on an area with limited or no competition via Actimab-MDS
in targeted conditioning. We have also leveraged our AWE or
Antibody Radiation Conjugate technology platform to add a different
modality, namely targeted radiation, to other areas of unmet or
underserved needs as evidenced by our Actimab-A plus Venetoclax
combinations and Actimab-A MRD trials. With our lead asset,
Iomab-B progressing well in its pivotal trial, the near-pivotal
Actimab-MDS program and the Iomab-ACT program for lymphodepletion
prior to CAR-T, our multi-asset pipeline will enable our company to
build a franchise opportunity in targeted conditioning which is
almost singular in the industry."
About Actinium Pharmaceuticals, Inc.
Actinium Pharmaceuticals Inc. is focused on improving patient
access and outcomes to cellular therapies such as bone marrow
transplant (BMT) and CAR-T with its proprietary, chemotherapy free
or sparing, targeted conditioning technology. Actinium is the only
company with a multi-disease, multi-target, drug development
pipeline focused on targeted conditioning. Its targeted
conditioning technology is enabled by ARC's or Antibody Radiation
Conjugates that combine the targeting ability of monoclonal
antibodies with the cell killing ability of radioisotopes.
Actinium's pipeline of clinical-stage targeted conditioning ARCs
target the antigens CD45 and CD33 for patients with a broad range
of hematologic malignancies including acute myeloid leukemia (AML),
myelodysplastic syndrome (MDS) and multiple myeloma (MM), acute
lymphoblastic leukemia (ALL), Hodgkin's lymphoma and Non-Hodgkin's
lymphoma. Actinium's Iomab-ACT program is designed to be a
universal lymphodepletion technology intended to eliminate the need
for chemotherapy-based conditioning prior to CAR-T or other
adoptive cellular therapies.
Iomab-B, Actinium's lead targeted conditioning product
candidate, is currently enrolling patients in the pivotal Phase 3
SIERRA trial in patients age 55 or older, with active, relapsed or
refractory AML. Iodine-131-apamistamab (Iomab-B), combines the
anti-CD45 monoclonal antibody labeled with iodine-131 for
myeloablation prior to a bone marrow transplant. CD45 is expressed
on leukemia, lymphoma and normal immune cells. Iomab-B has been
studied in over 500 patients in 10 clinical trials in numerous
hematologic diseases. Actinium's Iomab-ACT program is an expansion
of its CD45 program that is intended to be a universal,
chemotherapy-free solution for targeted lymphodepletion prior to
CAR-T. Through targeted lymphodepletion, the Iomab-ACT program is
expected to improve CAR-T cell expansion, reduce CAR-T related
toxicities and expand patient access to CAR-T treatment and
potentially other adoptive cell therapies. Due to its lower payload
dose, lymphodepletion with the Iomab-ACT program can be
accomplished through a single outpatient infusion. Actinium intends
to advance its Iomab-ACT program with CAR-T focused collaborators
from academia and industry.
Actinium is also developing its proprietary AWE or Antibody
Warhead Enabling technology platform which utilizes radioisotopes
including iodine-131 and the highly differentiated actinium-225
coupled with antibodies to target a variety of antigens that are
expressed in hematological and solid tumor cancers. The AWE
technology enables Actinium's internal pipeline and with the
radioisotope Actinium-225 is being utilized in a collaborative
research partnership with Astellas Pharma, Inc. Actinium's clinical
programs and AWE technology platform are covered by a portfolio of
75 patents covering composition of matter, formulations, methods of
use and also methods of manufacturing the radioisotope Actinium-225
in a cyclotron.
More information is available at www.actiniumpharma.com and our
Twitter feed @ActiniumPharma,
www.twitter.com/actiniumpharma.Forward-Looking Statements for
Actinium Pharmaceuticals, Inc.
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:
Actinium Pharmaceuticals, Inc.
Steve O'Loughlin
Principal Financial Officer
soloughlin@actiniumpharma.com
Investor Relations
Rx Communications Group
Paula Schwartz
917-322-2216
pschwartz@rxir.com
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