March 22, 2013 | by Wayne Lewis
Leukemia researchers reported a significant, but still experimental, stride against blood disease this week. In a small trial, they achieved remission in adults with relapsed B-cell acute lymphoblastic leukemia by reprogramming patients’ own T cells to fight the disease.
A common form of childhood cancer, this type of leukemia is rare but often deadly in adults; the study’s authors describe the prognosis as “dismal.” In the disease, the body drastically overproduces white blood cells that normally protect from infection, crowding out other blood cells.
The study, led by Memorial Sloan-Kettering scientists, found that in each participant, the treatment left the disease undetectable in the bloodstream.
Three of the five patients received the current standard of care, the blood stem cell transplant, as follow-up treatment and remain cancer-free. One of the original five patients died from a complication following transplant; another, who was ineligible for transplant, later relapsed.
Showing first-of-its-kind results in adults, the paper appeared in the March 20 issue of Science Translational Medicine and received prominent notice in The New York Times. The approach has the potential to treat other blood cancers and tumors as well, the Times reported.
In effect, the scientists’ approach enabled the immune system to defeat a uniquely dangerous foe — an immune system cancer.
The researchers collected white blood cells known as T cells from patients, and then altered them to hunt down the overabundant leukemia cells. The engineered cells recognized their quarry based on a particular protein, called CD19, found on the surface of B cells.
When the cells were reinfused into patients after chemotherapy, the Memorial Sloan-Kettering team saw a dramatic anti-cancer response, sometimes in a matter of days.
Other blood cancer experts, including those pursuing related approaches, were impressed as well.
“This is a very good and very important study. It will hopefully expand therapies for these types of patients,” said City of Hope’s Stephen J. Forman, M.D., who was not involved in this trial. An internationally known expert in leukemia, lymphoma and bone marrow transplantation, Forman is the Francis and Kathleen McNamara Distinguished Chair in Hematology and Hematopoietic Cell Transplantation.
He and his team, in previous research, had also identified CD19 as a potential target for leukemia and lymphoma.
At City of Hope, researchers are conducting clinical trials that use T-cell immunotherapy against B-cell lymphoma and an aggressive brain cancer called glioma, with plans to treat other types of tumors.
As one of the Memorial Sloan-Kettering researchers told the Times: “We’re creating living drugs. It’s an exciting story that’s just beginning.”