Researchers from the Baylor College of Medicine have found that activated Killer T cells in the lab that recognize specific antigens on the surface of lymphoma cells are an effective treatment for a number of patients with relapsed or recurring cancers of the lymph system.
According to Dr. Catherine Bollard, corresponding author, most individuals have these Killer T cells that are specifically directed against Epstein-Barr virus (herpesvirus). Nevertheless, these cells have difficulty in recognizing the tumor they should be attacking. Bollard was with the Cell and Gene Therapy Center at Baylor College of Medicine, Houston Methodist Hospital and Texas Children’s Hospital at the time of this publication. Now, she is with Children’s National Medical Center in Washington, D.C.
Dr. Cliona Rooney, professor in the Center for Cell and Gene Therapy, and one of the paper’s authors, noted, “We take the cells out and re-educate them in culture in the laboratory so that they regain their ability to attack the tumor.” What’s interesting is that this technique doesn’t alter the genetic makeup of the cells unlike other protocols. This procedure reactivates the ability of the T-cells to recognize tumor cells that express Epstein-Barr proteins and destroys them. This study involved patients with Hodgkin’s or non-Hodgkin’s lymphomas.
Researchers removed T-cells from patient’s blood, activated them and grew them in cell culture and then returned them to the patient. They were then ready to attack tumors.
The activated Killer T cells were given to 29 patients that were considered to be at high risk of relapse. Twenty-one patients who had relapsed or had therapy-resistant disease when they received the infusion were also given activated Killer T cells. Twenty-eight of the first 29 patients who received the newly activated T-cells as an adjuvant treatment remained in remission from their disease 3.1 years after treatment. Of the 21 with more severe disease, 13 responded to the treatment and 11 had complete remission without requiring pretreatment with chemotherapy.
No one died from lymphomas in the first group of patients, however nine died from complications linked with the extensive therapy involving chemotherapy and radiation they received as first-line treatment prior to relapse.
Bollard notes, “That’s why this research is so important. Patients with lymphomas traditionally have a good cure rate with chemotherapy and radiation. What kills them is the side effects of those treatments – second cancers, lung and heart disease. This is a targeted therapeutic approach that we hope can be used early in the disease to treat relapse. We saw good outcomes here. Eventually, it could be a front-line therapy.”
Rooney points out, while there is difficulty in tailor making Killer T cells for individuals this creates a barrier to therapy. However, current therapies are expensive and induce terrible side effects and often require hospitalization. “Although we spend some time making the cells, patients go home with few side effects and few associated hospital costs. It can be less costly than chemotherapy.”
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