BEVERLY HILLS, Calif.,
March 29, 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 that Dr. Jeffrey S. Miller, M.D., Deputy Director of the
Masonic Cancer Center at the University of
Minnesota and GT Biopharma's Consulting Chief Medical
Officer, presented updated interim Phase I/II clinical trial
results for the Company's lead therapeutic candidate, GTB-3550
TriKE™, being evaluated for the treatment of high-risk
myelodysplastic syndromes (MDS) and refractory/relapsed acute
myeloid leukemia (AML) at the Innate Killer Summit 2021, held
March 23-25. Dr. Miller's
presentation "NK Cell Therapeutics: Off-the-shelf Strategies to
Increase Activity and Specificity" highlighted the clinical power
of immune engagement with Interleukin-15 (IL-15) containing
TriKEs.
Highlights of GT Biopharma's updated interim GTB-3550 TriKE™
Phase I/II clinical trial results included:
- Up to 63.7% Reduction in Bone Marrow Blast Levels
- Restores Patient's Endogenous NK Cell Function,
Proliferation and Immune Surveillance
- No Progenitor-derived or Autologous/Allogenic Cell Therapy
Required
- No Cytokine Release Syndrome Observed
- 3 out of the Last 5 Patients Treated (25mcg/kg/day to
100mcg/kg/day) Respond
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 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. Further, we have yet to see toxicity (CRS -Cytokine
Release Storm) or any significant side effects, as is customary
with Cell Therapies and other NK Engagers. 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 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.
Contact:
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Institutional
Investors:
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Julie Seidel
Stern Investor Relations, Inc.
Julie.seidel@sternir.com
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.