GT Biopharma Advances GTB-3650 Phase 1 Trial to Cohort 2 Following Successful Initial Human Dosing and Evidence of Early Immune Activation Signals

Following the formal safety review of Cohort 1, no safety or tolerability issues were observed, allowing the company to move forward with Cohort 2.

The company plans on releasing more detailed results from Phase 1 later in 2025 following completion of additional dose cohorts.

SAN FRANCISCO, CALIFORNIA, May 19, 2025 (GLOBE NEWSWIRE) -- GT Biopharma, Inc. (the “Company”) (NASDAQ: GTBP), a clinical stage immuno-oncology company focused on developing innovative therapeutics based on the Company's proprietary TriKE^® natural killer (NK) cell engager platform, today announced successful completion of dosing in Cohort 1 and subsequent initiation of dosing in Cohort 2 of its Phase 1 dose escalation trial evaluating GTB-3650 for the treatment of relapsed or refractory (r/r) CD33 expressing hematologic malignancies.

GT Biopharma’s second-generation TriKE, GTB-3650, is currently being evaluated in a Phase 1 dose escalation trial for the treatment of relapsed or refractory (r/r) CD33 expressing hematologic malignancies. Cohort 1 has been successfully completed with patients having undergone the first and second dosing cycles. Following the formal safety review, no safety or tolerability issues were observed, allowing the company to move forward with Cohort 2, with the first patient now having been treated with the first dose cycle.

Based on multiple assays of various blood biomarkers, both patients in Cohort 1 have shown early evidence of increased immunologic activity, supporting GTB-3650’s ability to activate endogenous NK cells and induce NK cell expansion. The company plans on releasing more detailed results later in 2025 following enrollment and completion of additional dose cohorts.

The trial plans to evaluate GTB-3650 in up to approximately 14 patients (seven cohorts) and GTB-3650 will be dosed in two-week blocks, two weeks on and two weeks off, for up to four months based on clinical benefit. The trial will assess safety, pharmacokinetics, pharmacodynamics, in vivo expansion of endogenous patient NK cells and clinical activity. More details can be found on clinicaltrials.gov with the identifier: .

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 on 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’s natural killer 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 .

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TriKE^® is a registered trademark owned by GT Biopharma, Inc.

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