An experimental therapy that alters cancer patients’ own immune cells to identify a dangerous type of leukemia has also reduced tumors and sent the cancer into remission in adults, according to a new study published in Science Translational Medicine.
Similar immune-system therapy has proven effective in children with this cancer as well as in adults with a similar type of leukemia, however, this is the first time this specific therapy has worked in adults.
The findings of the current study were based on five patients with acute lymphoblastic leukemia (ALL). T cells were extracted from the patient and modified to express a receptor for protein on other immune cells – called B cells – that are found in both cancerous and healthy tissues.
For most patients, this puts the cancer in remission. However, it often comes back. The second treatment agenda is usually another round of chemotherapy followed by a bone marrow transplant.
The authors point out that when the cancer returns, it is often immune to many chemotherapy drugs. Therefore, Dr. Renier Brentjens, an oncologist at Memorial Sloan-Kettering Cancer Center in New York City, and his colleagues set out to test a different approach.
The five participating patients received infusions of their altered T cells after undergoing standard chemotherapy. All five patients saw a total remission – for one patient this occured within just eight days, according to the researchers.
Four of the patients then had a bone marrow transplant, while the fifth was ineligible due to heart disease. Dr. Michel Sadelain, another Sloan-Kettering researcher who worked on the study, said, “To our amazement, we got a full and a very rapid elimination of the tumor in these patients.”
Although these findings are exciting, the new therapy – known as adoptive T cell therapy – is not available outside the research setting and many questions remain to be answered.
“This is still an experimental therapy,” Brentjens said. “But it’s a promising therapy.”
Adoptive T cell therapy is a type of immunotherapy, an encouraging type of treatment which uses the patient’s own immune system to fight tumors.
This therapy is currently being explored as a “bridge” to a bone marrow transplant for ALL patients. However, Brentjens points out that the ultimate goal is to use it as an “up-front” therapy, in combination with chemotherapy, in an effort to prevent all recurrences from the start.
This is the first study of its kind to test the T cell therapy against adult ALL, but researchers have already explored it in some patients with advanced chronic lymphocytic leukemia (CLL).
The next question will be whether the T cell therapy can be used earlier in ALL treatment, however, the authors stress they are a long way off from that right now. Their goal is to eventually see how patients react after just the immunotherapy alone, without the bone marrow transplant.
Written by Kelly Fitzgerald