GT Biopharma's GTB-3550 Cuts Bone Marrow Blasts In High-Risk Patients With Hematological Malignancies

GT Biopharma Inc GTBP has reported updated interim data from Phase 1/2 clinical trial, evaluating the Company's lead candidate, GTB-3550, in high-risk myelodysplastic syndromes (MDS) and refractory/relapsed acute myeloid leukemia (AML).

• To date, nine patients have been enrolled in the trial. Patients were treated with doses of GTB-3550 below the anticipated therapeutic dose and maximum tolerated dose 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).
• CRS is a collection of symptoms that can develop as a side effect of certain immunotherapy types, especially involving T-cells.
• Five patients were treated with increasing doses of GTB-3550. Three of the five patients experienced a reduction in bone marrow blasts.
• Patient 7 at 50mcg/kg/day dose bone marrow blast levels decreased from 12% before therapy to 4.6% after GTB-3550 therapy.
• Patient 9 at 100mcg/kg/day dose level decreased from 22% before therapy to 8%.
• Correlative studies have shown reproducible endogenous ("native") NK cell activity in all patients. The data indicates GTB-3550 TriKE can potentially rescue the patient's exhausted/inhibited endogenous NK cells resulting in their activation, proliferation, and persistence.
• GTB-3550 is the Company's first TriKE product candidate. It 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.
• Price Action: GTBP shares were trading higher by 0.61% at $6.31on the last check Wednesday.