GT Biopharma (NASDAQ: GTBP) has announced that it submitted an investigational new drug (IND) application to the FDA in December 2025 for GTB-5550 TriKE, a B7-H3-targeted natural killer (NK) cell engager for the treatment of B7-H3 expressing solid tumor cancers.
According to GT, the planned Phase 1 trial of GTB-5550 will be the first dual nanobody TriKE tested with more patient-friendly subcutaneous dosing. The global solid tumor market is estimated at $362 billion.
In a statement, Michael Breen, executive chairman and CEO of GT, commented, “The IND for GTB-5550 represents another NK cell engager we plan to move into clinical development and a tremendous accomplishment for the company. As we continue actively enrolling the Phase 1 trial with GTB-3650 in myeloid blood cancer, we expect the next data readout in 1H 2026 could provide potential evidence of clinical activity. Initiation of a Phase 1 basket trial with GTB-5550 for multiple solid tumors is planned for 2026. We look forward to applying the clinical learnings from the GTB-3650 study to help inform the GTB-5550 program, which targets a patient population with B7-H3 expressing solid tumors that is orders of magnitude larger than the myeloid blood cancer patient population.”
