GT Biopharma (NASDAQ:GTBP) highlighted progress across its natural killer (NK) cell engager platform during a presentation at the RedChip Biotech Investor Conference, with Chairman and CEO Michael Breen outlining the company’s clinical history in blood cancers, its next planned move into solid tumors, and a longer-term opportunity in autoimmune disease.
TriKE platform and how the approach works
Breen described GT Biopharma as an oncology research company developing what it calls NK cell “engagers” to treat cancer and autoimmune disease. He emphasized that the company’s approach is not an NK cell therapy itself, but rather a protein-based therapy designed to “engage” endogenous NK cells—aiming to increase their activation, proliferation, and persistence.
- A CD16-binding element intended to attach to NK cells
- An interleukin-15 (IL-15) payload component that Breen characterized as a key differentiator
- A swappable “binder” that targets a specific antigen depending on the cancer or autoimmune indication
Breen referred to the construct as a “TriKE,” short for a trispecific NK engager platform, and said the modularity allows the company to pursue multiple targets by changing only the binder portion of the molecule.
First-in-human AML data from 2021
Breen reviewed results from a 2021 Phase 1 first-in-human trial in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) using what he called the company’s first-generation molecule, GTB-3550. He described a design that included six dose levels ranging from 5 mcg/kg/day to 150 mcg/kg/day, administered as three 96-hour infusion blocks with rest periods between them.
According to Breen, trial readouts showed NK cell activation and increased NK cell counts during treatment, with activation peaks corresponding to infusion timing. He also said the company observed reductions in bone marrow blast counts at higher dose levels in a subset of patients, citing examples including:
- A 33% reduction in one patient treated at 25 mcg/kg/day
- A 61.7% reduction in one patient treated at 50 mcg/kg/day
- A 63.6% reduction in one patient treated at 100 mcg/kg/day
- A 50% reduction in one patient treated at 150 mcg/kg/day
Breen presented those reductions as supportive signals for the mechanism, saying the results aligned with the company’s aim to drive NK cell activation and cancer cell killing.
Second-generation programs and near-term clinical plans
GT Biopharma is now advancing what Breen called a second-generation molecule, GTB-3650, in an ongoing Phase 1 blood cancer study targeting CD33. He said the company had treated seven patients and was “halfway through” the trial.
Breen also discussed a planned Phase 1 “basket” trial in solid tumors targeting B7-H3 with GTB-5550, which he said was expected to begin “very shortly.” He told the audience that “pretty much 90% of all solid tumors highly express B7-H3,” describing it as a well-regarded target pursued by other oncology research companies.
In the Q&A session, Breen said FDA clearance of the IND for the solid tumor program was “extremely important,” and he framed it as a key step as the company prepares to begin the Phase 1 solid tumor trial.
Market opportunity and autoimmune disease angle
Breen cited estimates placing the global solid tumor market at approximately $362 billion annually and the autoimmune disease market at about $115 billion annually. He said the company’s planned solid tumor basket trial would include prostate, breast, ovarian, head and neck, lung, bladder, and pancreatic cancers.
He also discussed an autoimmune disease candidate, GTB-7550, targeting CD19, which he described as a “go-to target” for autoimmune disease. Breen said the company hopes to start manufacturing work for the autoimmune program “later in this year, early next year.” He added that, based on preclinical work, the second-generation molecule was estimated to be “somewhere between 10x and 40x more potent” than the first generation.
In response to a question about why the platform could matter in oncology, Breen characterized the approach as a potentially more “humane solution” by leveraging the body’s immune system, contrasting it with chemotherapy, radiation, and surgery.
Leadership and financial runway
Breen identified Alan Urban as CFO and credited Dr. Jeffrey Miller and Dr. Martin Felices of the University of Minnesota as key inventors behind the company’s science. He described Miller as a key opinion leader in the NK cell engager field, citing his publication record and role at the Masonic Cancer Center.
Breen also said that as of January 2026 the company had approximately $9 million in cash, which he said was sufficient to fund operations into the fourth quarter of the year.
About GT Biopharma (NASDAQ:GTBP)
GT Biopharma, Inc is a clinical-stage biopharmaceutical company dedicated to developing novel immuno-oncology therapies utilizing its proprietary Tri-specific NK cell engager (TriKE) platform. This technology is designed to harness and enhance the body’s natural killer (NK) cells by simultaneously binding tumor antigens and interleukin-15 (IL-15), stimulating NK cell proliferation and targeted cytotoxicity. By focusing on NK cell engagement rather than T-cell activation, the company aims to offer therapies with potentially improved safety profiles and reduced immune-related adverse events.
The company’s lead candidate, GTB-3550, is currently in clinical trials for hematologic malignancies such as acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL) and myelodysplastic syndromes (MDS).
