February 15 was International Childhood Cancer Day and to mark the occasion we spoke with Dr. Sarah Alexander, a new BCCHR investigator and pediatric oncologist at BC Children’s Hospital who specializes in some of the most common childhood cancers, including non-Hodgkin lymphoma and acute lymphoblastic leukemia (ALL).
Dr. Sarah Alexander joined BCCHR in October, 2025 and is researching how to improve care for children with non-Hodgkin lymphoma and acute lymphoblastic leukemia.
Dr. Alexander obtained her medical degree from Harvard Medical School in 1994. Prior to joining BCCHR in October 2025, she worked as a clinical director of Haematology/Oncology and a pediatric oncologist in the Leukemia and Lymphoma Section at The Hospital for Sick Children (SickKids) in Toronto.
She is now the head of the Division of Hematology, Oncology & Bone Marrow Transplant, and the Team Nicky Hospital Chair in Hematology, Oncology and BMT at BC Children’s Hospital.
We spoke to Dr. Alexander about her work and her hopes for the future of treating kids with cancer.
What is the focus of your research?
Broadly speaking, the aim of my research is to improve the chance of cure for kids with ALL and non-Hodgkin lymphoma and reduce the side effects of existing treatment.
We are incredibly fortunate to be in an era of new treatments for childhood cancer. For kids with ALL and non-Hodgkin lymphoma, the advances in immunotherapy — treatments that use the immune system to recognize, attack, and destroy cancer cells — are leading to substantial benefits. I was part of the team that recently published a study in the New England Journal of Medicine. We found that adding a new immunotherapy treatment called blinatumomab to standard chemotherapy led to increased survival in children that were newly diagnosed with ALL. For many kids with these cancers, including immunotherapy as part of their treatment is now considered the standard of care.
How do these immunotherapy treatments work?
Blinatumomab is a molecule known as a bispecific T-cell engager (BiTE). It works by linking a patient’s healthy T cells to both normal and leukemic B cells. When activated this way, the T cells can attack and kill the leukemia B cells. Adding BiTEs to chemotherapy can make a big impact controlling the cancer.
But this is just one form of newly developed immunotherapy. Other immunotherapy treatments for B-cell ALL include chimeric antigen receptor (CAR) T-cell therapy. This treatment works by genetically altering the patient’s own T cells to seek out and destroy the cancer cells. The difference between these two treatments is that blinatumomab largely stops once you stop giving the drug, while CAR-T cell therapy is a “living drug” that may persist lifelong.
Other types of immunotherapy treatment for children with cancer include drugs known as checkpoint inhibitors. Programmed cell death protein 1 (PD-1) is a molecule that acts like a switch on T cells, shutting it down when activated. Checkpoint inhibitors can cover up PD-1 so that these “brakes” aren’t able to be used, enabling cancer-targeting T cells to continue their attacks without the threat of being shut down. This category of immunotherapy medicines are now a core component of optimal therapy for some children with Hodgkin lymphoma.
Cancer cells in the blood.
How do we make these treatments safer?
Although these new treatments and combinations of therapies for childhood cancer are a welcome addition to the clinician’s arsenal of tools, we must also consider the short- and long-term site effects.
For example, treatments such as blinatumomab have short-term and potentially longer-term impacts on the child’s immune system. Kids receiving blinatumomab may have higher risks of infection during their chemotherapy treatment. Ongoing studies are looking at how long ALL therapy affects the immune system. This has practical implications, such as determining the best approach to re-vaccinating children after they complete treatment.
Answering these questions about how to best and most safely incorporate immunotherapy into optimal treatment regimens for kids and teens with ALL and non-Hodgkin lymphoma will help inform best care for kids during and post treatment.
What brought you to BC Children’s Hospital and what are your hopes for the future?
The attraction of moving to BC Children’s Hospital was in large part because of the excellence of the team caring for kids with cancer and serious blood disorders and for the opportunities to continue to pursue clinically relevant research. But I also wanted to come to Vancouver as it is such a beautiful city with loads of opportunities for exploring.
What excites me most about the future is how we build on the work that came before us. Previous generations of researchers transformed childhood leukemia and lymphoma from almost uniformly fatal diseases into ones that are now curable for most children and teens. The ongoing work will focus on maximizing the chances of cure while making the therapy less burdensome and minimizing the risks of long-term sequelae.
