On December 21, 2020 GT Biopharma, Inc. (OTCQB: GTBP) (GTBP.PA) an immuno-oncology company focused on innovative therapies based on the Company’s proprietary NK cell engager (TriKE) technology platform reported the presentation of additional interim data results for the Company’s lead therapeutic candidate, GTB-3550, for the treatment of high-risk myelodysplastic syndromes (HR-MDS) (Press release, GT Biopharma, DEC 21, 2020, View Source;gtb-3550-trike-reduces-cancer-cells-by-61-7-for-a-high-risk-myelodysplastic-syndromes-hr-mds-patient-301196659.html [SID1234573183]).

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Erica Warlick, M.D, Principal Investigator for the GTB-3550 clinical trial, presented additional clinical data results with the treatment with HR-MDS patient #7 of its TriKE GTB-3550 during the Q&A session following her presentation at the 62nd American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition. Dr. Warlick’s HR-MDS patient presentation can be viewed on the GT Biopharma web site at View Source

Mr. Anthony Cataldo, the Chairman and Chief Executive Officer of GT Biopharma commented, "Our clinical data demonstrates that our proprietary TriKE (CD16/IL15/CD33), safely activated and harnessed the patient’s native NK cell’s cancer killing ability in a target-directed fashion without side effects. Which is not the case with highly expensive and intrusive supplemental NK cell therapies. We look forward to progressing to the next level."

Clinical Benefit Achieved

Prior to being treated with TriKE GTB-3550, the HR-MDS patient failed hypomethylating agent (HMA) and Luspatercept therapies. With TriKE GTB-3550 at 50mcg/kg/day (three consecutive 96-hour continuous infusions), the patient achieved a successful bone marrow blast level reduction from 12% before GTB-3550 therapy to 4.6% post GTB-3550 therapy determined by morphological assessment, Additionally, the patient achieved stable hematologic parameters including normal platelet counts throughout therapy. Following this single course of GTB-3550 TriKE therapy causing significant reduction in bone marrow blast levels, the patient achieved clinical benefit from GTB-3550 therapy, which qualified patient #7 to receive a hematopoietic stem cell transplant (HSCT).

No Toxicities / Potent Native NK Cell Activation and Proliferation achieved without Supplemental NK Cell Therapy

The patient exhibited NO SIDE AFFECTS or signs of clinical immune activation, and NO DOSE LIMITING TOXICITY such as cytokine release syndrome (CRS) or serious adverse events (SAEs) or fevers, tachycardia or constitutional symptoms which are synonymous with other NK Cell Therapy and NK Engagers. Correlative studies showed no shedding of CD16 from patient’s NK cells, and potent NK cell activation, proliferation and target cell killing without the need for supplemental autologous NK cell therapy.

Targeted delivery of IL-15 to NK cells via GTB-3550 TriKE therapy showed preferential proliferation of NK cells, significantly less effect on CD8+ T-cells, and no observed toxicity at 25x the previous reported MTD for continuous infusion of recombinant human IL-15. GTB-3550 TriKE 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.

GTB-3550 Therapy Prior to Hematopoietic Stem Cell Transplant (HSCT)

The only treatment with curative intent for a majority of elderly HR-MDS or relapsed/refractory AML patients is allogeneic hematopoietic stem cell transplant (HSCT). Age is one of the strongest risk factors associated with poor outcome. Difficulties in treating elderly patients include comorbidities, reduced performance status, and a disease biology with more frequent aberrant cytogenetics and multidrug resistance. There is a significant gap between elderly patients in need of HSCT, and those actually receiving HSCT due to their failure to meet the eligibility requirements. TriKEGTB-3550 represents a novel, low intensity therapeutic option which has the potential to increase HSCT eligibility for elderly HR-MDS and relapsed/refractory AML patients.

Mr. Anthony Cataldo, the Chairman and Chief Executive Officer of GT Biopharma commented "we are gratified that GTB-3550 TriKE achieved the threshold of clinical benefit, and the HR-MDS patient became eligible for HSCT." Mr. Cataldo further stated "we believe our clinical data demonstrates that our proprietary CD16 and IL-15 incorporated in TriKE safely activates and harnesses the patient’s native NK cell’s cancer killing ability in a target-directed fashion without the need for highly expensive and intrusive supplemental NK cell therapies. The TriKE platform biologic technology is demonstrating its capabilities as a first in class drug never before done technology."

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 acute myeloid leukemia (AML), another aggressive cancer with poor outcomes.

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 GTB-3550 TriKE

GTB-3550 is the Company’s first TriKE product candidate being initially developed for the treatment or relapsed/refractory acute myeloid leukemia (AML), high-risk myelodysplastic syndrome (HR-MDS). 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 cancer cells.