An exciting therapy for leukemia once again shines a light on its efficacy – this time, nearly 71 percent of terminal leukemia patients saw their tumors shrink or disappear following the clinical trial.
The study, published in the Journal of Clinical Oncology, included 24 patients with chronic lymphocytic leukemia (CLL) who had failed other treatments. They ranged in age from 40 to 73 years and each had tried an average of five therapies prior to their participation in the trial, including treatment with ibrutinib – a widely used cancer drug for CLL. This placed them in a high-risk group with short survival rates.
The team of researchers from Fred Hutchinson Cancer Research Center used an up-and-coming treatment called chimeric antigen receptor (CAR) T-cell immunotherapy. This is a type of therapy where a patient’s own T-cells are extracted from their blood and altered in the lab. In this case, they were modified to recognize CD19, a target on the surface of leukemia cells.
These modified cells were then infused back into the patients, whereby they became fighters against cancer, multiplying and hunting down cancer cells with the CD19 antigen. After six and a half months, the researchers report that 17 out of 24 patients had their tumors shrink or disappear.
"It was not known whether CAR T-cells could be used to treat these high-risk CLL patients," said lead author Dr. Cameron Turtle, an immunotherapy researcher at Fred Hutchinson, in a statement. "Our study shows that CD19 CAR T-cells are a highly promising treatment for CLL patients who have failed ibrutinib."
Chronic lymphocytic leukemia is a condition that starts in a person’s bone marrow, the soft tissue inside bones where blood cells are made. In patients with CLL, their bone marrow makes too many abnormal lymphocytes, a type of white blood cell.
As the disease progresses, these abnormal lymphocytes can collect and grow in the lymph nodes, spleen, and liver. These "lymphoid tumors" can be measured in size using various imaging scans.
Healthy lymphocytes are the body’s warriors, helping to fight infection, but for those with CLL, they go awry and wreak havoc. The American Cancer Society estimates there will be 4,660 deaths from CLL in 2017 alone, with about 20,110 new cases.
There were considerable side-effects to the therapy, though most of them were reversible. Around 83 percent of the patients experienced cytokine release syndrome, a common complication following T-cell therapy with symptoms such as fever, nausea, chills, and abnormally low blood pressure. Unfortunately, two patients were hospitalized and one patient died during the course of the treatment.
To check that those in remission remained that way, the team analyzed samples from 12 of the patients' bone marrow four weeks after treatment. Of those, seven had no malignant copies of cancer.
The study is still in its early stages, but shows considerable promise. The side effects are a legitimate concern, though the potential of remission is a huge boon.
Just last week, the FDA panel recommended the approval of Novartis’ CAR-T therapy for B-cell acute lymphoblastic leukemia in children and young adults. The FDA is expected to make their final decision by October 3, 2017.