FDA Receives IND for GTB-3650 in CD33+ AML and MDS


A phase 1 trial plans to be initiated in 2024 to investigate GTB-3650 for the treatment of patients with CD33-positive leukemia.

  • GTB-3650 is a second-generation nanobody natural killer (NK) cell engager.
  • The therapeutic is being developed for the treatment of patients with acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS).
  • Preclinical findings of GTB-3650 have demonstrated high potency and enhanced binding affinity.

An investigational new drug (IND) application has been submitted to the FDA for the development of GTB-3650 for patients with CD33-positive leukemia, including relapsed/refractory AML and high-risk MDS.1

GTB-3650 is a novel molecule based on camelid single-domain antibody technology. The second-generation nanobody NK cell engager based on the manufacturer’s proprietary technology is being developed for the treatment of CD33-positive leukemia.2

A phase 1 trial to evaluate GTB-3650 for the treatment of patients with CD33-positive leukemia is expected to begin in 2024.3

“Today’s announcement is an important milestone for GT Biopharma, and we look forward to advancing GTB-3650 for treatment of CD33-positive leukemia. We are excited to expeditiously move this molecule into the clinic as we execute on our clinical objectives in 2024,” stated Michael Breen, executive chairman, board of directors and interim chief executive officer of GT Biopharma, in a press release.1

Compared with GTB-3550, GT Biopharma’s lead second-generation Tri-Specific Killer Engager (TriKE) program, GTB-3650 has shown high potency in preclinical models, as well as enhanced binding affinity.2 The preclinical safety profile of the 2 agents is similar.

The TriKE platform is designed to employ and boost the cancer killing abilities of the immune system’s natural killer cells in patients.

  1. GT Biopharma announces IND submission for GTB-3650 for treatment of CD33+ leukemia. News release. GT Biopharma, Inc. December 4, 2023. Accessed December 4, 2023. https://tinyurl.com/33pxwu2w
  2. GT Biopharma advances GTB-3650, a second-generation tri-specific killer engager -TriKE®, into IND-enabling studies. News release. September 13, 2021. Accessed December 4, 2023. https://tinyurl.com/5n798499
  3. GT Biopharma reports third quarter 2023 financial results. News release. GT Biopharma, Inc. November 1, 2023. Accessed December 4, 2023. https://tinyurl.com/2s4x3xnc
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