Christopher Dvorak, MD (right), and Janel Long-Boyle, PharmD, PhD (left), report in the journal Blood Advances that children with blood cancers who were treated with a personalized dosage of chemotherapy had a reduction in side effects and increase in survival rates. Photo by Susan Merrell
While reviewing patients’ charts early in the morning, pediatric hematologist-oncologist Christopher Dvorak, MD, used to feel his heart race when he read about a child with blood cancer getting a stem cell transplant.
Stem cells are the body’s building block cells that can develop into other cells, such as blood cells. A stem cell transplant — a procedure that replaces unhealthy stem cells with healthy ones — helps increase children’s chances of surviving blood cancers, like leukemia, and other blood-based illnesses.
Before a transplant, patients receive chemotherapy and radiation to ‘condition’ their body to accept the new, healthy stem cells. The conditioning eliminates the body’s current stem cells, weakens the immune system, and destroys any remaining cancerous cells. Even so, Chris knew the long-term prognoses for these kids were grim. Historically, only a third of blood cancer patients who received a stem cell transplant survived three years without relapse.
These days, however, Dvorak and fellow transplant specialists at UCSF Benioff Children’s Hospital’s Blood & Marrow Transplant Clinic are breathing easier. Recent research showed that over 86% of children survived three years without relapse thanks to a new conditioning treatment Dvorak’s team developed.
The findings, reported in Blood Advances and supported by the National Institutes of Health (NIH) through the National Cancer Institute (NCI), mean more children are surviving with little reminder of ever having had childhood cancer.
The original chemotherapy conditioning guidelines — still used today in children — were developed over 50 years ago for adults and based merely on height and weight. To achieve higher survival rates and reduce long-term side effects, Dvorak and his team developed a conditioning treatment that gives children the least amount of chemotherapy needed and skips radiation entirely.
“Optimal chemotherapy conditioning accounts for not only children’s height and weight but also many other personalized factors like immune cell count and kidney function that helps us calculate a precise amount of chemotherapy and eliminate the need for radiation,” said Dvorak, lead study author and chief of the UCSF Allergy, Immunology and Bone Marrow Transplantation Division in Pediatrics.
In this race, every child needs a champion
Up to now, there wasn’t a lot of science behind chemotherapy conditioning for stem cell transplant, according to Janel Long-Boyle, PharmD, PhD, UCSF professor of Clinical Pharmacy and co-author of the paper. “It is sad to say, but we were basically guessing at how best to treat kids, while giving them far too much chemo and radiation,” said Long-Boyle.
Haunted by her own sister’s leukemia treatment, Long-Boyle developed an algorithm to compute a precise chemotherapy conditioning dose — based on kids’ genetics, sex, race, immune cell count, kidney function, and other factors, in addition to height and weight. The precision chemo and lack of radiation help save children from long-term side effects, like infertility and other cancers.