GT Biopharma Doses First Patient in Subcutaneous B7-H3 NK Engager Trial
GT Biopharma dosed the first patient on May 14 in its Phase 1 dose-escalation basket trial of GTB-5550, a B7-H3-targeted natural killer cell engager using subcutaneous dosing. As of March 31, the company held approximately US$9 million in cash, supporting operations through Q4 2026.
1. Phase 1 Dosing Milestone
On May 14, GT Biopharma initiated its Phase 1 dose-escalation basket trial for GTB-5550 by dosing the first patient, prioritizing advanced prostate, ovarian and pancreatic cancer cohorts that have failed prior therapy.
2. GTB-5550 Molecule Design
GTB-5550 is a 2nd-generation Tri-specific Killer Engager combining a camelid anti-CD16 arm, a wild-type IL-15 linker and a camelid anti-B7-H3 arm; preclinical data suggest 10–40 times greater potency than earlier TriKE versions.
3. Financial Runway and Catalyst Timeline
With a cash balance of approximately US$9 million at March 31, GT Biopharma expects runway through Q4 2026, targeting key Phase 1 dose-escalation updates in 2H 2026 as enrollment progresses.