BEVERLY HILLS, Calif., March 17,
2021 /PRNewswire/ -- GT Biopharma, Inc. (NASDAQ: GTBP)
a clinical stage immuno-oncology company focused on developing
innovative therapeutics based on the Company's proprietary NK cell
engager (TriKE™) protein biologic technology platform is pleased to
announce updated interim Phase I/II clinical trial results for the
Company's lead therapeutic candidate, GTB-3550, being evaluated for
the treatment of high-risk myelodysplastic syndromes (MDS) and
refractory/relapsed acute myeloid leukemia (AML).
Reduction in Bone Marrow Blast Levels Achieved
To date, 9 patients have been enrolled in the Phase I/II
Expansion clinical trial. Patients enrolled early in the Study
(patients 1-4) were treated with doses of GTB-3550 below the
anticipated therapeutic dose (RP2D) and maximum tolerated dose
(MTD) to address possible safety concerns. All patients
treated at the lower doses exhibited no signs of toxicity, and did
not experience any Grade of Cytokine Release Syndrome (CRS).
Patients 5-9 were treated with increasing doses of GTB-3550
(25mcg/kg/day, 50mcg/kg/day and 100mcg/kg/day,
respectively). Three of the five patients (60%) experienced
reduction in bone marrow blasts with two patients (one patient
treated at the 50mcg/kg/day dose level and one patient treated at
the 100mcg/kg/day dose level) experiencing significant reductions
in bone marrow blast levels. As previously reported, Patient 7
treated at the 50mcg/kg/day dose level achieved a 61.7% reduction
in bone marrow blast levels from 12% before therapy to 4.6% after
GTB-3550 therapy. Patient 9 treated at the 100mcg/kg/day dose
level achieved a 63.7% reduction in bone marrow blast levels from
22% before therapy to 8% after therapy. All patients treated
at these higher doses of GTB-3550 did not experience any Grade of
Cytokine Release Syndrome (CRS).
No Cytokine Release Syndrome (CRS) Observed
All patients treated to date with GTB-3550 TriKE displayed no
signs of any Grade of cytokine release syndrome (CRS). Of
particular note, GTB-3550 is currently being administered to
patients at doses significantly higher than the reported MTD
(Maximum Tolerated Dose) for continuous infusion of recombinant
human IL-15 (Interleukin-15) (Waldmann, TA et al, Clin Cancer Res. (2019)
25:4945–54). GTB-3550 is a single-chain, tri-specific scFv
recombinant fusion protein conjugate composed of the variable
regions of the heavy and light chains of anti-CD16 and anti-CD33
antibodies, and a modified form of IL-15.
Improved NK Cell Function, Proliferation &
Persistence
Correlative studies have shown reproducible endogenous
("native") NK cell activity in all patients. NK cell activation
increases early during treatment. This finding correlated with
an increase proportion and absolute number of NK cells during
treatment. Targeted delivery of IL-15 to NK cells via GTB-3550
TriKE showed preferential proliferation of NK cells and
significantly less effect on CD8+ and CD4+ T-cells. We also
observed no CD16 shedding by patients' NK cells, and saw enhanced
HL-60 AML target cell killing. This data indicates GTB-3550
TriKE™ rescues the patient's exhausted/inhibited endogenous NK
cells resulting in their activation, proliferation and
persistence.
Mr. Anthony Cataldo, the Chairman
and Chief Executive Officer of GT Biopharma commented: "We are
pleased with the continued clinical performance of our lead
GTB-3550 TriKE™ product candidate as we continue dose
escalation." Mr. Cataldo further stated "this early data
indicates GTB-3550 therapy demonstrates significant bone marrow
blast level reductions in AML and MDS patients without the need for
expensive progenitor-derived or autologous/allogenic cell
therapies. We believe as we continue to dose escalate GTB-3550
TriKE™, more patients will experience greater clinical efficacy.
TriKE's ability to work in the patient without outside supplemental
engineered NK cells or the need for any combination drugs, sets
TriKE apart from other cancer therapies. This is also the reason
why TriKE™ therapy will be significantly less expensive than other
treatments, opening the door to an off-the-shelf therapeutic."
About High-Risk Myelodysplastic Syndromes (MDS)
MDS is a rare form of bone marrow-related cancer caused by
irregular blood cell production within the bone marrow. As a result
of this irregular production, MDS patients do not have sufficient
normal red blood cells, white blood cells and/or platelets in
circulation. High-risk MDS is associated with poor prognosis,
diminished quality of life, and a higher chance of transformation
to acute myeloid leukemia. Approximately 40% of patients with
High-Risk MDS transform to AML, another aggressive cancer with poor
outcomes.
About Acute Myeloid Leukemia (AML)
Acute myeloid leukemia (AML) is a type of cancer in which the
bone marrow makes abnormal myeloblasts (a type of white blood
cell), red blood cells, or platelets. According to the
National Cancer Institute (NCI), the five-year survival rate is
about 35% in people under 60 years old, and 10% in people over 60
years old. Older people whose health is too poor for intensive
chemotherapy have a typical survival of five to ten months. AML
accounts for roughly 1.8% of cancer deaths in the United States.
About GTB-3550 TriKE™
GTB-3550 is the Company's first TriKE™ product candidate being
initially developed for the treatment AML. GTB-3550 is a
single-chain, tri-specific scFv recombinant fusion protein
conjugate composed of the variable regions of the heavy and light
chains of anti-CD16 and anti-CD33 antibodies and a modified form of
IL-15. The natural killer (NK) cell stimulating cytokine human
IL-15 portion of the molecule provides a self-sustaining signal
that activates NK cells and enhances their ability to kill. We
intend to study GTB-3550 in CD33 positive leukemias such as acute
myeloid leukemia (AML), myelodysplastic syndrome (MDS), and other
CD33+ hematopoietic malignancies.
About GTB-3550 TriKE™ Clinical Trial
Patients with CD33+ malignancies (primary induction failure or
relapsed AML with failure of one reinduction attempt or high-risk
MDS progressed on two lines of therapy) age 18 and older are
eligible (NCT03214666). The primary endpoint is to identify
the maximum tolerated dose (MTD) of GTB-3550
TriKE. Correlative objectives include the number, phenotype,
activation status and function of NK cells and T cells.
About GT Biopharma, Inc.
GT Biopharma, Inc. is a clinical stage biopharmaceutical company
focused on the development and commercialization of immuno-oncology
therapeutic products based our proprietary TriKE™ NK cell engager
platform. Our TriKE™ platform is designed to harness and
enhance the cancer killing abilities of a patient's immune system
natural killer cells (NK cells). GT Biopharma has an exclusive
worldwide license agreement with the University of Minnesota to further develop and
commercialize therapies using TriKE™ technology. For more
information. Please visit www.gtbiopharma.com
Forward-Looking Statements
This press release contains certain forward-looking statements
that involve risks, uncertainties and assumptions that are
difficult to predict, including statements regarding the potential
acquisition, the likelihood of closing the potential transaction,
our clinical focus, and our current and proposed trials.
Words and expressions reflecting optimism, satisfaction or
disappointment with current prospects, as well as words such as
"believes", "hopes", "intends", "estimates", "expects", "projects",
"plans", "anticipates" and variations thereof, or the use of future
tense, identify forward-looking statements, but their absence does
not mean that a statement is not forward-looking. Our
forward-looking statements are not a guarantee of performance, and
actual results could differ materially from those contained in or
expressed by such statements. In evaluating all such statements, we
urge you to specifically consider the various risk factors
identified in our Form 10-K for the fiscal year ended
December 31, 2020 in the section titled "Risk Factors" in Part
I, Item 1A and in our subsequent Form 10Q Quarterly filings with
the Securities and Exchange Commission, any of which could cause
actual results to differ materially from those indicated by our
forward-looking statements.
Our forward-looking statements reflect our current views with
respect to future events and are based on currently available
financial, economic, scientific, and competitive data and
information on current business plans. You should not place
undue reliance on our forward-looking statements, which are subject
to risks and uncertainties relating to, among other
things: (i) the sufficiency of our cash position and our
ongoing ability to raise additional capital to fund our operations,
(ii) our ability to complete our contemplated clinical trials,
or to meet the FDA's requirements with respect to safety and
efficacy, (iii) our ability to identify patients to enroll in our
clinical trials in a timely fashion, (iv) our ability to
achieve approval of a marketable product, (v) design,
implementation and conduct of clinical trials, (vii) the
results of our clinical trials, including the possibility of
unfavorable clinical trial results, (vii) the market for, and
marketability of, any product that is approved, (viii) the
existence or development of treatments that are viewed by medical
professionals or patients as superior to our products,
(ix) regulatory initiatives, compliance with governmental
regulations and the regulatory approval process, and social
conditions, and (x) various other matters, many of which are
beyond our control. Should one or more of these risks or
uncertainties develop, or should underlying assumptions prove to be
incorrect, actual results may vary materially and adversely from
those anticipated, believed, estimated, or otherwise indicated by
our forward-looking statements.
We intend that all forward-looking statements made in this press
release will be subject to the safe harbor protection of the
federal securities laws pursuant to Section 27A of the
Securities Act, to the extent applicable. Except as required by
law, we do not undertake any responsibility to update these
forward-looking statements to take into account events or
circumstances that occur after the date of this press
release. Additionally, we do not undertake any responsibility
to update you on the occurrence of any unanticipated events which
may cause actual results to differ from those expressed or implied
by these forward-looking statements.
For more information, please visit www.gtbiopharma.com.
Contact:
Institutional
Investors:
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Julie
Seidel
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Stern Investor
Relations, Inc.
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Julie.seidel@sternir.com
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212-362-1200
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Investor
Relations:
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Media Relations
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David
Castaneda
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Susan
Roush
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David@gtbiopharma.com
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Susan@gtbiopharma.com
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414-351-9758
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805-624-7624
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SOURCE GT Biopharma, Inc.