Pioneering New Horizons in Cancer Therapy
Advancing a Novel Treatment for Solid Tumors
GT Biopharma has announced its intention to launch a Phase 1 clinical trial for GTB-5550 TriKE, a promising new therapeutic agent designed to combat solid tumors characterized by B7-H3 expression. This significant step follows the successful submission of an Investigational New Drug (IND) application to the U.S. Food and Drug Administration (FDA) in December 2025.
The Strategic Vision Behind GTB-5550 TriKE
GTB-5550 TriKE functions as a B7-H3-targeted natural killer (NK) cell engager, a cutting-edge approach in immunotherapy. Michael Breen, Executive Chairman and CEO of GT Biopharma, underscored the importance of this milestone, stating that GTB-5550 represents the third NK cell engager pipeline program slated for clinical evaluation. This achievement reflects the company's dedication to expanding its portfolio of innovative cancer therapies.
Leveraging Prior Successes for Future Endeavors
The commencement of a Phase 1 basket trial for various solid tumor types is anticipated in 2026. GT Biopharma plans to integrate valuable clinical insights gained from the ongoing GTB-3650 study, which targets myeloid blood cancer, into the development of the GTB-5550 program. This strategic transfer of knowledge is expected to optimize the trial design and accelerate progress for patients with B7-H3-expressing solid tumors.
Trial Design: A Detailed Approach to Patient Care
The Phase 1a segment of the trial will involve a dose escalation process, meticulously evaluating up to seven different dose levels to ascertain the maximum tolerated dose (MTD). Subsequently, the Phase 1b component will focus on dose expansion, confirming the MTD across seven distinct metastatic disease cohorts while continuously assessing its tolerability, provided similar toxicity profiles are observed across groups.
Treatment Regimen and Patient Monitoring
Patients enrolled in the study will receive GTB-5550 via subcutaneous injection in the abdominal area for five consecutive days during weeks one and two, followed by a two-week hiatus from treatment. Each treatment cycle spans four weeks, with a minimum of two cycles planned. Disease reassessments will occur after two cycles and subsequently every 8-12 weeks. Treatment may continue until disease progression, unacceptable toxicity, patient withdrawal, or when it is no longer deemed to be in the patient's best interest. Participants will be monitored for 12 months to evaluate progression-free survival (PFS) and overall survival (OS).
Market Impact and Stock Performance
The global market for B7-H3 expressing solid tumor cancers constitutes a significant portion of the estimated $362 billion worldwide solid tumor market, highlighting the potential impact of GTB-5550. Following the announcement, GTBP stock experienced a positive movement, recording a 12.92% increase to $0.75 in premarket trading on Thursday, signaling investor confidence in the company's research and development efforts.