On May 15, 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 first quarter 2026 financial results for the period ended March 31, 2026.

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"With the initiation of our GTB-5550 Phase 1 trial, we have now advanced three TriKE candidates into the clinic, a significant milestone that underscores the continued momentum of our pipeline," said Michael Breen, Executive Chairman and Chief Executive Officer. "GTB-3650 has demonstrated an excellent safety profile thus far, and we look forward to continuing enrollment progress. With sufficient cash runway through Q4 2026, we look forward to providing updates on both programs in the second half 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 is ongoing, with Cohort 4 enrollment now complete and a total of 8 patients treated across the first four cohorts; the Company expects to provide continued progress updates throughout 2026. 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 ongoing Phase 1 trial with GTB-5550 is the first nanobody TriKE tested with more patient-friendly subcutaneous dosing. The Phase 1a dose escalation portion of the trial is focused primarily on enrolling prostate cancer patients and will evaluate up to 6 dose levels to identify the maximum tolerated dose (MTD). After the dose escalation phase, the Phase 1b expansion component will enroll patients with up to 7 different tumor types (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.

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. Subsequent cycles receive treatment three times weekly for 2 weeks followed by 2 weeks of no treatment. 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). More details can be found on clinicaltrials.gov with the identifier: NCT07541573.

First Quarter Ended March 31, 2026 Financial Summary

Cash Position: The Company had cash and cash equivalents of approximately $9 million as of March 31, 2026, 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 second quarter of 2026 were approximately $400,000 compared to $1.1 million for the same comparable quarter of 2025. The $700,000 decrease was primarily due to a reduction in production costs. R&D expenses primarily relate to the Company’s continued licensing, development, production, and clinical trials of its most advanced TriKE product candidates GTB-3650 and GTB-5550 along with the progression on other promising product candidates.

Selling, General and Administrative (SG&A) Expenses (Excluding Stock Compensation): SG&A expenses for the second quarter of 2026 were approximately $2.4 million compared to $800,000 for the same comparable quarter of 2025. The $1.6 million increase was primarily due to an increase in marketing expenses, and to a lesser extent, legal fees.

Loss from Operations: The Company reported a loss from operations for the second quarter of 2026 of approximately $2.8 million compared to $1.9 million for the same comparable quarter of 2025. The 900,000 increase was primarily due to $1.6 million increase in SG&A (as described above).

Net Loss: The Company reported a net loss of approximately $2.8 million for the second quarter of 2026, compared to $800,000 for same comparable quarter of 2025. The $2 million increase consisted primarily of a $1.6 million increase in SG&A (as described above), and a decrease in non-recurring other income of approximately $1.1 million.

(Press release, GT Biopharma, MAY 15, 2026, View Source [SID1234665803])