Immune System Therapy Shows Promise in Adults with Leukemia

A recent study of an experimental therapy that alters cancer patients’ own immune cells to recognize an often-deadly form of leukemia has shrunk tumors and sent the cancer into remission in adults. While a similar immune system approach had previously shown promise in children with acute lymphoblastic leukemia (ALL), as well as in adults with a related form of leukemia, it is the first study to prove this therapy works in adults. ALL is more common in children but especially deadly when it occurs in adults. Current treatments cure an estimated 80 percent to 90 percent of children with ALL, but they are effective in only 30 percent or fewer of adult cases.

In the study, scientists extracted T cells from five patients ages 23, 56, 58, 59 and 66 with ALL. The T cells were then mixed with a harmless virus that inserted genes for a three-part molecule: one part that trains T cells to recognize homing beacons on the leukemic cells, called CD19; one part that instructs T cells to kill any such cells they find; and one part that makes T cells survive longer than usual. The cells were then returned to the patients. Four of the patients’ leukemia became undetectable in 18 to 59 days, and the fifth patient achieved remission eight days after treatment. According to Michel Sadelain, a doctor with Memorial Sloan- Kettering Cancer Center in New York who was co-leader of the study, the results were dramatic considering several of the patients had bone marrow “chock full of leukemia.” The treatment, however, did come with complications. Two of the patients experienced a cytokine storm, which led to plummeting blood pressure and spiking fever. Both cases were managed with steroids.

The researchers have since successfully treated three additional patients, and they suspect the results might be better if treatment is begun earlier. They are raising funds for a larger study to be conducted at Sloan-Kettering, as well as other cancer centers.