Telling parents that their child’s leukemia has not responded to treatment or has returned after initially successful treatment is one of the hardest things I do as a pediatric hematologist-oncologist.
Acute lymphoblastic leukemia (ALL) is the most common cancer diagnosed in U.S. children. Substantial progress has been made against this blood cancer. Current standard treatments allow about 90 percent of children to live long-term without relapse.
A breakthrough
Until last summer, however, there were very few treatments to offer the remaining 10 percent, which includes more than 200 children in the U.S. each year. But then, the U.S. Food and Drug Administration (FDA) approved the first of a revolutionary new type of cancer treatment called CAR T–cell therapy. Now, I have an exciting new treatment to talk about with the parents of some of these children.
The CAR T-cell therapy that was approved is called tisagenlecleucel (Kymriah). It can be used for treating children and young adults up to the age of 25 who have the most common type of ALL, B-cell ALL. Currently, tisagenlecleucel is only for patients whose B-cell ALL has not responded to standard treatments or has returned after treatment at least twice.
B-cell ALL is so-called because the leukemia originates in immune cells called B cells. The cancerous B cells almost always have a protein called CD19 on their surface, and this is the target of tisagenlecleucel.
How it works
Each patient receives a customized dose of tisagenlecleucel. It is created using immune cells called T-cells extracted from the patient’s blood. The extracted T-cells are reprogrammed by genetic modification to recognize and attack cells with CD19 on their surface. After the T cells are modified, they are expanded in number and then infused back into the patient, where they multiply and hunt down the CD19-positive cancerous B cells.
In the clinical trial that led to tisagenlecleucel’s approval, 83 percent of the children and young adults who received the treatment went into remission.
Continuing research
This is truly a breakthrough for patients, but it does not come without risks. The amped up T-cells can cause severe side effects, so tisagenlecleucel is currently only available at certified health care facilities.
Researchers, many of whom are members of the American Association for Cancer Research, are working to develop next generation CAR T–cell therapies that have fewer side effects and improved effectiveness, and I look forward to a future in which I can offer my patients and their families a range of treatment options.
