Fred Hutch researcher Dr. Colleen Delaney has been working for several years to realize the promise of blood stem cells present in babies’ umbilical cords — generally discarded at childbirth — to save the lives of cancer patients. The stem cells present in cord blood are less developed than adult blood stem cells, and so can be used for stem cell transplantation without the strict tissue matching required in a traditional matched donor transplant. However, each cord blood donation has a relatively small number of stem cells and this significantly increases the time it takes for the new blood and immune system to take hold, or engraft.
Delaney, who directs the Hutch’s Cord Blood Program, and her colleagues have developed a technique for significantly growing (“expanding”) the number of stem cells in cord blood and freezing and storing the resulting product. Because of the types of cells present in the final product, it can be used as needed “off the shelf” without regard to tissue typing. These expanded cord blood stem cells have been tested with promising results in several clinical trials to provide patients going through cord blood transplant with a bridge of infection-fighting cells while they wait for blood and immune system recovery.
These cells may have therapeutic value outside the transplant setting as well, as a study published recently in The Lancet Haematology suggests. Led by Delaney, that study asked whether the expanded cord blood cells could be used as supportive care for patients with acute myeloid leukemia, or AML, who received intensive chemotherapy. Such treatment for AML and other blood cancers leaves patients depleted of their white blood cells and thus especially vulnerable to dangerous infections. As in the transplant setting, the researchers hypothesized that the expanded cells might provide a temporary bridge of infection-fighting cells and help the patient’s own blood cell count recover faster, thus protecting patients from the related treatment complications.
In a small Phase 1 trial designed to test the approach’s safety and feasibility, the researchers gave the expanded cord blood cells to 29 AML patients receiving a particular combination of chemotherapy called GCLAC and compared them to 106 patients receiving only GCLAC. Some patients went on to a second cycle of GCLAC with expanded cells. This was a first-in-human clinical trial, and one safety concern was that patients could be at risk for expanded cell product-related graft-vs.-host-disease or have an immune reaction to the expanded cell product. These are risks that patients wouldn’t otherwise face receiving chemotherapy alone, said Adrienne Papermaster, a project manager in Delaney’s laboratory. But the study found that the cord blood product was safe for patients, and as expected the cells lived on in patients’ bodies only transiently.
When compared to 106 patients who received GCLAC alone, the researchers also found that the 29 patients who received the expanded cord blood cells had lower rates of documented infections — meaning, those infections in which clinicians could pinpoint the exact cause — even though the patients did not seem to have more rapid white blood cell count recovery than the control group. Delaney and her colleagues are planning a larger follow-up trial focused on determining the effectiveness of the expanded cell product and how it may help to prevent infection in the intensive chemotherapy setting.
— Rachel Tompa / Fred Hutch News Service
Fred Hutch immunologist Dr. Justin Taylor is one of 12 young investigators nationwide to receive an Individual Biomedical Research Award from the Hartwell Foundation. The Memphis, Tennessee-based foundation supports early-stage, innovative and cutting-edge biomedical research on diseases affecting children. Taylor will receive $100,000 a year for three years to investigate using targeted genetic engineering to provide life-ong protection against respiratory syncytial virus, or RSV.
RSV is a leading cause of severe respiratory illness in young children, particularly infants born prematurely or with chronic lung disease or congenital heart disease. According to the U.S. Centers for Disease Control and Prevention, RSV infections cause 60,000 hospitalizations and 200 deaths each year in children under 5 years old. Virtually every U.S. child is infected with RSV before age 2 and can be re-infected year after year. Efforts to develop an effective vaccine have been unsuccessful.
Taylor’s proposal calls for a radically different strategy: Using targeted genetic engineering to reprogram a small number of the patient’s B cells to generate an antibody known to neutralize RSV. If successful, the strategy — involving only a one-time blood draw and no booster shots — could be used against other pathogens as well.
“This is a ‘high-risk, high reward’ type of project that I would never have been able to dedicate this type of effort to without this grant,” Taylor said. The funding not only will cover laboratory experiments but allow him to hire a postdoctoral fellow or technician to work full time on the project.
Taylor joined Fred Hutch in spring 2014 to research the immunology of B cells, a type of white blood cell responsible for producing antibodies. In addition to the Hartwell award, he also recently received a highly competitive sustaining grant — a large, multi-year research grant known as an R01 — to fund his work on HIV-specific “naïve” B cells that are capable of protecting a person against HIV, the virus that causes AIDS, but need to be “trained” by a vaccine to do so. That funding will allow him to hire a full-time postdoc and full-time tech to work exclusively on this work, he said.
Additionally, his lab was also awarded funding as a portion of two grants awarded to other researchers. He will work with Fred Hutch’s Dr. Jim Kublin to analyze how the microbiome affects vaccine responses and with Tulane University Health Sciences Center’s Dr. James MacLachlan to assess how substances added to vaccines to increase the body’s immune response control and direct the response at the intestinal mucosa, or the lining of the gastrointestinal tract.
“It goes without saying this was a pretty exciting period of time for me,” said Taylor, who spoke with Fred Hutch News Service last year about the excitement — and challenges — of setting up his first lab. “Scientifically it's really rewarding to have you and your lab's hard work and ideas validated by these awards. And it's also nice to have a little more career certainty and know that I'll have a lab for the next five years. Now I just have to keep working hard.”
— Mary Engel / Fred Hutch News Service