GlobeNewswire·May 14, 2026, 8:30 AM ET

GT Biopharma Announces First Patient Dosed in Phase 1 Trial of GTB-5550, a B7-H3-Targeted Natural Killer (NK) Cell Engager for Solid Tumors

GT Biopharma has dosed the first patient in the Phase 1 dose escalation basket trial for GTB-5550, the third TriKE to enter clinical testing.
The trial targets solid tumors expressing B7-H3 & is the first nanobody TriKE tested using subcutaneous dosing.
The Phase 1a dose escalation phase will focus primarily on prostate cancer patients across up to 6 dose levels to identify the maximum tolerated dose.
The Phase 1b expansion component will enroll patients with up to 7 tumor types including castration-resistant prostate cancer, ovarian cancer, breast cancer, head & neck cancer, non-small cell lung cancer, pancreatic cancer, & bladder cancer.
GTB-5550 is administered via subcutaneous injection in the abdomen for 5 consecutive days during Week 1 & 2 of a 4-week cycle, with subsequent cycles given three times weekly for 2 weeks followed by 2 weeks off.
The company anticipates providing trial updates in the second half of 2026 as enrollment progresses.
The trial identifier for GTB-5550 is NCT07541573.