GT Biopharma Announces FDA Clearance of Investigational New Drug (IND) Application for GTB-5550 TriKE®, a B7-H3-Targeted Natural Killer (NK) Cell Engager for Solid Tumors Expressing B7-H3
Rhea-AI Summary
GT Biopharma (NASDAQ: GTBP) announced FDA clearance of its IND for GTB-5550, a B7-H3-targeted TriKE® NK cell engager, enabling a Phase 1 dose-escalation basket trial expected to initiate in mid-2026. The trial will test subcutaneous dosing across up to 7 solid tumor cohorts, with dose escalation to identify an MTD.
Unaudited proforma cash of approximately $9 million as of January 31, 2026 is anticipated to extend runway through Q4 2026.
Positive
- FDA clearance of GTB-5550 IND enables Phase 1 initiation in mid-2026
- Phase 1 design includes up to 7 solid tumor cohorts for broad signal detection
- GTB-5550 uses dual nanobody TriKE format with subcutaneous dosing for patient convenience
Negative
- Unaudited proforma cash ~$9 million expected to fund operations only through Q4 2026
- GTB-5550 is at Phase 1 stage, so safety and efficacy remain unproven in humans
News Market Reaction
On the day this news was published, GTBP gained 2.29%, reflecting a moderate positive market reaction. Argus tracked a peak move of +17.2% during that session. Argus tracked a trough of -14.8% from its starting point during tracking. Our momentum scanner triggered 19 alerts that day, indicating notable trading interest and price volatility. This price movement added approximately $311K to the company's valuation, bringing the market cap to $14M at that time.
Data tracked by StockTitan Argus on the day of publication.
Key Figures
Market Reality Check
Peers on Argus
GTBP fell 22.69% while several biotech peers (e.g., LIPO, SLRX) showed double‑digit gains. Momentum data flags one peer (PBM) moving down, with no peers in the same direction as the target, supporting a stock‑specific reaction to this IND clearance.
Previous Clinical trial,fda approval Reports
| Date | Event | Sentiment | Move | Catalyst |
|---|---|---|---|---|
| Jun 27 | IND clearance | Positive | -7.1% | FDA cleared GTB‑3650 IND for Phase 1 trial in CD33+ leukemia. |
The prior FDA IND clearance event for GTB‑3650 in Jun 2024 saw a -7.08% move, suggesting the stock has previously sold off on seemingly positive trial‑start milestones.
Over the past several quarters, GT Biopharma has steadily advanced its TriKE® NK‑cell platform, including GTB‑3650 for CD33+ hematologic malignancies and GTB‑5550 for B7‑H3–expressing solid tumors. Earlier updates highlighted safe dose escalation for GTB‑3650 and plans to move GTB‑5550 into the clinic, alongside tight cash levels and going‑concern disclosures. The current FDA clearance for the GTB‑5550 IND builds on that trajectory, moving a second program into Phase 1 while financial and listing constraints from recent S‑1 and 424B3 filings remain part of the backdrop.
Historical Comparison
Past FDA IND clearance (GTB‑3650, Jun 2024) led to a -7.08% move. Today’s -22.69% reaction to GTB‑5550 IND clearance is a much larger downside response than prior same‑tag news.
The company has progressed from GTB‑3650 IND clearance for CD33+ leukemia to GTB‑5550 IND clearance for B7‑H3–positive solid tumors, expanding its TriKE® platform from hematologic to solid tumor indications.
Market Pulse Summary
This announcement advances GTB‑5550 into a Phase 1 basket trial with subcutaneous dosing across up to seven metastatic solid tumor cohorts, following earlier progress with GTB‑3650. The trial focuses on B7‑H3–expressing tumors and includes 12‑month follow‑up for PFS and OS. Recent SEC filings highlight going‑concern language, Nasdaq listing risk, and significant potential dilution from registered shares, making future financing, clinical safety, and early efficacy data key metrics to monitor.
Key Terms
investigational new drug (ind) regulatory
natural killer (nk) cell medical
b7-h3 medical
cd16 medical
il-15 medical
subcutaneous (sq) medical
progression free survival (pfs) medical
AI-generated analysis. Not financial advice.
GTB-5550 Phase 1 dose escalation basket trial expected to initiate mid-2026
Phase 1 protocol allows multiple solid tumor types known to express B7-H3
Unaudited proforma cash balance as of January 31, 2026 of approximately
SAN FRANCISCO, CALIFORNIA, Feb. 03, 2026 (GLOBE NEWSWIRE) -- GT Biopharma, Inc. (the “Company”) (NASDAQ: GTBP), a clinical stage immuno-oncology company focused on developing innovative therapeutics based on the Company's proprietary TriKE® natural killer (NK) cell engager platform, today announced FDA clearance of its IND application for GTB-5550, allowing the company to proceed with a Phase 1 clinical trial, which is anticipated to initiate in mid-2026.
“FDA clearance of our third TriKE® IND, GTB-5550, represents a defining moment for GT Biopharma as we bring another NK cell engager into the clinic”, said Michael Breen, Executive Chairman and Chief Executive Officer of GT Biopharma. “We expect to commence enrollment of the Phase 1 basket trial in mid-2026. While the phase I trial is open to patients with common solid tumors that express B7-H3, in the dose-escalation component we will prioritize enrollment for advanced prostate, ovarian, and pancreatic cancer patients who have failed standard therapies. Based on the encouraging trends we have seen from our ongoing Phase 1 trial with GTB-3650 in AML patients, we are even more enthusiastic about the potential benefits of GTB-5550 treatment in patients with solid tumors known to express B7-H3.”
GTB-5550 is a camelid (cam) anti-CD16/WT IL-15/cam anti-B7-H3 tri-specific natural killer (TriKE) cell engager, with a single chain recombinant TriKE® comprised of three components joined by flexible linkers: 1) a nanobody arm that engages the CD16 activating receptor (camelid anti-CD16) on natural killer (NK) cells; 2) a wildtype IL-15 (WT IL-15) linker arm to drive NK cell proliferation, priming, and survival; and 3) a nanobody arm that specifically engages B7-H3 (camelid anti-B7-H3) to target the antigen expressed on tumor cells.
“This clearance is an important step toward developing new immune-based therapies for patients with advanced prostate cancer and other solid tumor types”, said Dr. Emmanuel Antonarakis, MD, Associate Director, Translational Research at the University of Minnesota Masonic Cancer Center1. “Given the high expression of B7-H3 in over
The Phase 1 trial with GTB-5550 will be the first dual nanobody TriKE® tested with more patient-friendly subcutaneous dosing. The Phase 1a dose escalation portion of the trial will test up to 6 dose levels to identify the maximum tolerated dose (MTD). After the dose escalation phase , the Phase 1b expansion component of the trial will then confirm the MTD identified in the Phase 1a trial in up to 7 different possible metastatic disease cohorts (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. 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).
About GT Biopharma, Inc.
GT Biopharma, Inc. is a clinical stage biopharmaceutical company focused on the development and commercialization of immuno-oncology therapeutic products based on our proprietary TriKE® NK cell engager platform. Our TriKE® platform is designed to harness and enhance the cancer killing abilities of a patient’s immune system’s natural killer cells. GT Biopharma has an exclusive worldwide license agreement with the University of Minnesota to further develop and commercialize therapies using TriKE® technology. For more information, please visit gtbiopharma.com.
Forward-Looking Statements
Certain statements in this press release may constitute "forward-looking statements" regarding future events and our future results. All statements other than statements of historical facts are statements that could be deemed to be forward-looking statements. These statements are based on current expectations, estimates, forecasts, and projections about the markets in which we operate and the beliefs and assumptions of our management. Words such as "expects," "anticipates," "targets," "goals," "projects", "intends," "plans," "believes," "seeks," "estimates," "endeavors," "strives," "may," or variations of such words, and similar expressions are intended to identify such forward-looking statements. Readers are cautioned that these forward-looking statements are subject to a number of risks, uncertainties and assumptions that are difficult to predict, estimate or verify. Therefore, actual results may differ materially and adversely from those expressed in any forward-looking statements. Such risks and uncertainties include those factors described in our most recent annual report on Form 10-K, as such may be amended or supplemented by subsequent quarterly reports on Form 10-Q, or other reports filed with the Securities and Exchange Commission. Readers are cautioned not to place undue reliance on these forward-looking statements. The forward-looking statements are made only as of the date hereof, and we undertake no obligation to publicly release the result of any revisions to these forward-looking statements. For more information, please refer to our filings with the Securities and Exchange Commission.
TriKE® is a registered trademark owned by GT Biopharma, Inc.
Investor Relations Contact:
LifeSci Advisors
Corey Davis, Ph.D.
cdavis@lifesciadvisors.com
212-915-2577
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1 The University of Minnesota, pursuant to its license agreement with GT Biopharma, is entitled to receive royalties should commercial sales of product using the TriKE technology be realized, including GTB-3650 and GTB-5550. This interest has been reviewed and managed by the University of Minnesota in accordance with its conflict of interest policies.
FAQ
What did GTBP announce about the GTB-5550 IND on February 3, 2026?
When will the GTBP GTB-5550 Phase 1 trial start and which cancers will it include?
How will GTB-5550 be administered in the GTBP Phase 1 study?
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