A Larger Pool of Donor Cells

One option for people without a match is to be transplanted with stem cells from umbilical cord blood. A patient can safely receive cord blood cells that aren’t quite a perfect match because cord blood transplants are less likely to result in the donor cells attacking the recipient’s tissues, a serious and potentially life-threatening complication called graft versus host disease (GVHD).

The world’s first cord blood transplant with an unrelated donor was performed at Duke in 1993 by Joanne Kurtzberg, MD, in a pediatric patient. Three years later, Kurtzberg, who is the Jerome S. Harris Distinguished Professor of Pediatrics, transplanted unrelated cord blood into an adult.

“For the first few years, it was only [being done] at Duke, both in adults and pediatric patients,” Kurtzberg said. “We were integrally a part of the clinical trials that ultimately spread the technology to most academic medical centers around the world.”

Today, more than 50,000 of these transplants have been performed worldwide.

Cord blood transplants are particularly valuable to Black, Asian, and Latino people because these groups are underrepresented on national donor registries. That makes it harder for them to find perfect matches, which occur more frequently within rather than between ethnic groups.

More Options for Chemo

It used to be that most cancer patients undergoing bone marrow transplant first had high doses of chemotherapy to wipe out every last cancer cell. But researchers have discovered that sometimes transplanted cells can recognize and kill the cancer that eluded the patient’s immune system. Some patients, with some types of blood cancer, do well with a low dose of chemo, whose primary purpose is to suppress the patient’s immune system so it won’t reject the donor cells.

The low-dose, or reduced-intensity transplant makes stem cell transplant available to older patients and those with other medical conditions who might not be able to endure high doses of chemotherapy.

Bone marrow transplant can be arduous. Before the transplant, patients need chemo, and afterward they frequently need platelet transfusions or other interventions while their new immune system is growing. They also need to be closely monitored for signs of infection. For these reasons, patients typically spend weeks in the hospital after the transplant, which can be emotionally challenging and carries the risk of being exposed to other people’s germs. In 1992, Duke became the first medical center in the nation to begin an outpatient bone marrow transplant program. Even today, Duke is one of only a few medical centers to offer this option. Patients receive a transfusion, then go home or to a nearby apartment if they don’t live near Duke. They come to the outpatient clinic several times a week for supportive care. This option isn’t appropriate for all patients, but Alyea said about half of Duke’s high-dose transplants are outpatient.

Nelson Chao, MD, chief of the Division of Cell Therapy in the Department of Medicine, wants to go one step further. He is working with Anthony Sung, MD, associate professor of medicine, on a clinical trial to see whether patients do better when the follow-up care is provided at home.

“That is novel to Duke,” said Chao, who is the Donald D. and Elizabeth G. Cooke Cancer Distinguished Research Professor. “I don’t think anyone else is doing that in this country. I think we are going to see better outcomes.” The idea is that staying at home will help patients maintain their own unique microbiomes — the population of bacteria and other microbes on their skin and in their bodies — rather than picking up microbes from frequent visits to the clinic, and that this will result in fewer complications. The trial was underway with teams providing in-home care when the COVID pandemic hit. The experience of those teams allowed the bone marrow transplant program to quickly pivot and provide at-home care for all transplant outpatients for the first four months of the pandemic to protect them from the new virus.

The Future of Stem Cell Transplant

In addition to saving lives of people with blood cancer or bone marrow disease, stem cell transplant can be used with other conditions. Duke physicians are using it to successfully treat certain autoimmune diseases, such as scleroderma and multiple sclerosis. In babies and children, Duke physicians use it to treat inherited disorders related to metabolism, blood, or the immune system. The field of stem cell transplant has also set the stage for promising new immunotherapies for cancer. “Bone marrow transplant was the first immunotherapy,” Alyea said. “We gave cells [to the patient] with the idea that the cells would mediate an anti-disease response.” Emerging immunotherapies take that a step further, by engineering cells to make them better cancer killers before transfusing them into the patient. Some are already FDA-approved and many more are in the pipeline. Currently, these types of engineered-cell therapies are effective in about half of patients, but researchers are hard at work to change that. “The hope is that [one day] these therapies can be so specific that they can cure cancer with a single dose, and the person wouldn’t need a transplant or any other treatment,” Kurtzberg said. Until then, Duke physicians will continue to provide patients undergoing stem cell transplants with the best experience and outcome possible. “Our program is dedicated to patient care first,” Chao said. “We are patient-centered and patient-focused.”