University of Minnesota researchers have initiated a ground breaking clinical trial to determine the optimal dose and safety of T regulatory cells (T-regs) to decrease the risk of immune reactions common in patients undergoing blood and marrow transplantation.
Ultimately, the researchers hope the experimental cellular therapy will improve overall survival rates for blood cancer patients as well as offer a potential new paradigm for treating autoimmune diseases.
"Toward our quest of making transplants even safer for adults and children with leukemia, lymphoma, multiple myeloma, and other blood and marrow disorders, we are exploring the possibility of using T-regs to enhance the rate of blood and marrow recovery and reduce the risks of graft-versus-host disease, a complication that affects more than 60 percent of patients," said Claudio Brunstein, M.D., principal investigator of the study.
T-regs are a type of lymphocyte, or white blood cell that normally regulates the body's immune responses. In the case of transplant, donor T-regs may suppress the recipient's immune system so that the healthy donor's blood-forming stem cells and immune cells can grow, helping ward off life-threatening graft-versus-host-disease (GVHD). GVHD occurs when the immune cells within the donated cells attack the body of the transplant recipient. GVHD causes one-third of deaths after transplant.
Researchers have proven in animal models that infusing T-regs after transplant increases the chance of blood and marrow recovery and decreases the risk of GVHD.
"Once we identified that T-regs were highly effective in mouse models, we then spent three years finding ways to make this therapy valuable for transplant patients and potentially useful for patients with autoimmune diseases," said Bruce Blazar, M.D., director of the Center for Translational Medicine at the University.
The T-regs in this study are isolated from umbilical cord blood (blood collected from the placenta or afterbirth after the birth of a child) because they occur in higher frequency than what is typically found in most adults and are easier to expand in culture prior to treatment. This is the first human clinical trial in the world that uses T-regs derived from umbilical cord blood.
This trial is designed to find the highest possible safe dose of T-regs in immune suppressed patients undergoing a double umbilical cord blood transplant for leukemia, other blood cancer, or bone marrow failure. From data in animal models, University researchers believe there will be no acute side effects with the T-regs.
If the data in humans mimics animal models, T-regs will be a powerful therapy to prevent GVHD and enhance engraftment in transplant patients. Once safety and efficacy data are known, researchers hope to test T-regs for treatment of various autoimmune diseases, such as type I diabetes and multiple sclerosis. University researchers hypothesize that if T-regs are transplanted early in the life of the disease, the cells may help prevent disease progression.
"This is an exciting time. In the near future, I anticipate being able to combine immune cell populations, like T-regs, that stop immune reactions responsible for autoimmune diseases like diabetes, and immune responses to stem cell infusion given to repair already damaged tissues. This brings great hope not only for adults and children with cancer but many other diseases as well. At the close of this clinical trial, we hope to go right to our first clinical trial with T-regulatory cells in the treatment of newly diagnosed diabetes," said John E. Wagner, M.D., director of the pediatric hematology-oncology and blood and marrow transplantation program at the University of Minnesota.
This study is funded by the National Institutes of Health, the National Cancer Institute, the National Heart Lung and Blood Institute, and National Institute of Allergy and Infectious Diseases, the Leukemia and Lymphoma Society, the National Marrow Donor Program, and the Children's Cancer Research Fund.