On March 2, 2026 GT Biopharma, Inc. (the "Company") (NASDAQ: GTBP), a clinical stage immuno-oncology company focused on developing innovative therapeutics based on the Company’s proprietary natural killer (NK) cell engager TriKE platform, reported full year 2025 financial results for the period ended December 31, 2025.

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"2026 looks to bring more significant milestones for the company, as we plan to initiate the first clinical trial with GTB-5550," said Michael Breen, Executive Chairman and Chief Executive Officer. "Advancing our third TriKE candidate into the clinic underscores the continued momentum of our pipeline. GTB-3650 has shown an excellent safety profile thus far, and the higher dose cohorts will be more reflective of surpassing a potential efficacy threshold. With sufficient cash runway through Q4 2026, we look forward to providing the next update in the third quarter of 2026."

GTB-3650 TriKE for CD33 positive leukemias

The ongoing Phase 1 dose escalation study is evaluating GTB-3650 for relapsed or refractory (r/r) CD33 expressing hematologic malignancies, including refractory acute myeloid leukemia and high-risk myelodysplastic syndrome. Enrollment in Cohort 4 (10 µg/kg/day) is ongoing, and the Company expects to initiate dosing in Cohort 5 (25 µg/kg/day) in Q2 2026. The Company anticipates providing the next update in the third quarter of 2026, which would include longer term follow-up on the six patients in Cohort 1 through 3 as well as initial observations from patients in Cohort 4 and Cohort 5. Dose escalation may continue up to Cohort 7 as necessary with the potential to evaluate GTB-3650 in a total of 14 patients (two patients per cohort). GTB-3650 is dosed in two-week blocks, two weeks on and two weeks off, for up to four months based on clinical benefit. The trial aims to assess the safety, pharmacokinetics, pharmacodynamics, in vivo expansion of endogenous patient NK cells and clinical activity.

GTB-5550 TriKE for B7H3 positive solid tumor cancers

The Phase 1 basket trial with GTB-5550 will be the first dual nanobody TriKE tested with more patient-friendly subcutaneous dosing. The Phase 1a dose escalation portion of the trial will test up to 6 dose levels to identify the maximum tolerated dose (MTD). After the dose escalation phase, the Phase 2 expansion component of the trial will then confirm the MTD identified in the Phase 1a trial in up to seven different possible metastatic disease cohorts (castration-resistant prostate cancer, ovarian cancer, breast cancer, head and neck cancer, non-small cell lung cancer, pancreatic cancer, and bladder cancer) and further evaluate its safety, tolerability and preliminary anti-tumor activity. The Company remains well on track to initiate the trial in mid-2026.

GTB-5550 will be administered by subcutaneous (SQ) injection in the abdominal area for 5 consecutive days during Week 1 and Week 2 followed by 2 weeks of no treatment. One treatment cycle is 4 weeks in duration. A minimum of 2 cycles is planned, and patient-appropriate disease reassessment is performed after 2 cycles and every 8-12 weeks thereafter. Treatment may continue until disease progression, unacceptable toxicity, patient refusal, or treatment is no longer in the best interest of the patient. Patients are followed for 12 months to determine progression free survival (PFS) and overall survival (OS).

Year Ended December 31, 2025 Financial Summary

Cash Position: The Company had cash and cash equivalents of approximately $7 million as of December 31, 2025, and an unaudited proforma cash balance as of January 31, 2026 of approximately $9 million, which is anticipated to be sufficient to fund the Company’s operations through the fourth quarter of 2026.

Research and Development (R&D) Expenses: R&D expenses for the year ended December 31, 2025 were approximately $3.5 million compared to $5.8 million for the prior year. The $2.3 million decrease was primarily due to a reduction in production and material costs. R&D expenses primarily relate to the Company’s continued licensing, development and production of its most advanced TriKE product candidates GTB-3650 and GTB-5550 along with the progression on other promising product candidates. In late June 2024, the Company received clearance from the Food and Drug Administration with respect to its Investigational New Drug ("IND") application in relation to its next generation GTB-3650 camelid nanobody product. Study enrollment began in early 2025 and the Company has advanced into the clinic, enrolling patients, and performing tests for data collection throughout the year. In late January 2026, the Company received clearance from the FDA with respect to its IND Application in relation to GTB-5550, with a Phase 1 dose escalation basket trial expected to initiate mid-2026.

Selling, General and Administrative (SG&A) Expenses (Excluding Stock Compensation): SG&A expenses for the year ended December 31, 2025 were relatively flat compared to the prior year, amounting to approximately $8.5 million compared to $8.3 million, respectively.

Loss from Operations: The Company reported a loss from operations of approximately $12.4 million for the year ended December 31, 2025, compared to $14.4 million for the prior year. The $2 million decrease consisted primarily of significant decreases in R&D expenses (as described above).

Net Loss: The Company reported a net loss of approximately $28.4 million for the year ended December 31, 2025, compared to $13.2 million for the prior year. The $15.2 million increase consisted almost entirely of a non-cash expense resulting from the change in fair value of additional investment rights connected to the Company’s Series L Preferred Stock during the year.

(Press release, GT Biopharma, MAR 2, 2026, View Source [SID1234663200])