FDA gives green light to first human trial testing cancer drug GTB-5550
Priority enrollment planned for those with advanced pancreatic cancer
Written by |
A first-in-human clinical trial will launch in the coming months to test GTB-5550, an immune therapy from GT Biopharma that’s designed to treat various types of cancer, including pancreatic cancer, in patients whose tumors express a protein marker called B7-H3.
GT announced that the U.S. Food and Drug Administration (FDA) has given the green light to an application giving the company the go-ahead to launch the trial. The initial Phase 1a dose-escalation portion of the study will test as many as six different doses of GTB-5550, with the aim of identifying the maximum tolerated dose — meaning, the highest dose that can be given without unacceptable safety risks.
Then, the second Phase 1b expansion part of the study will test that maximum dose in a larger group of participants, specifically those with solid tumors carrying the B7-H3 marker.
“We expect to commence enrollment of the Phase 1 basket trial in mid-2026,” Michael Breen, executive chairman and CEO of GT, said in a company press release. A basket trial tests how well a therapy works in people with different types of cancer sharing a common mutation or biomarker.
“While the [Phase 1] 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,” Breen said.
GTB-5550 targets tumors carrying protein marker B7-H3
GTB-5550 is a next-generation treatment designed to help the body’s natural killer (NK) cells find and destroy cancer cells. It works by directly linking NK cells to tumor cells that carry the B7-H3 marker, while also delivering a built-in activation signal that helps NK cells multiply and stay active.
As their name implies, NK cells can kill other cells, including cancer cells. The basic aim of GTB-5550 is to bring these cancer-killing immune cells in close proximity to the cancer cells and activate them to induce an anticancer immune response in people with various cancer types.
In the upcoming clinical trial, GTB-5550 will be administered by subcutaneous, or under-the-skin, injection into the abdomen. Injections will be given in four-week cycles: for the first two weeks, patients will receive daily injections for five consecutive days; then, for the next two weeks, no injections will be given. Based on the study’s design, each participant is expected to undergo at least two of these four-week treatment cycles, with the potential for additional cycles based on individual response factors.
All participants will then be followed for at least one year to track disease progression and survival outcomes.
A similar treatment from GT, called GTB-3650, is now being tested in people with certain leukemias, a type of blood cancer.
“Based on the encouraging trends we have seen from our ongoing Phase 1 trial with GTB-3650 in [acute myeloid leukemia] patients, we are even more enthusiastic about the potential benefits of GTB-5550 treatment in patients with solid tumors known to express B7-H3,” Breen said.
