Both ESFT and AR develop due to chromosomal translocations, which fuse a gene from one chromosome to a different chromosome. The dendritic vaccine included peptides derived from each patient's individual cancer in a way that was designed to alert a patient's immune system to the unique genetic alteration on the cancer cells.
In this clinical trial of 52 patients, researchers attempted to use immunotherapy as "consolidation" therapy that is, after standard therapy provided a remission. Patients underwent aphaeresis to harvest blood lymphocytes that were then frozen. From this, dendritic cells were later extracted. These are cells that present an antigen to T cells and other immune system fighters in order to elicit a response.
All patients then had chemotherapy, radiation or surgery, as appropriate, and in some cases a stem cell transplant to induce remission. The 30 patients who initiated immunotherapy received a common flu vaccine, as well as their own lymphocytes and their own dendritic cells, which had been infused with tumor antigens. Some of these patients also received interleukin-2, which stimulates activity of T cell lymphocytes.
"The good news was the surprisingly nice T cell response patients had to the flu vaccination, even relatively soon after completing chemotherapy," Mackall said. "That shows that the general idea of using immunotherapy following chemotherapy to prevent recurrence is not a flawed one. Chemotherapy depleted the immune system, but we could restore it."
The bad news, she added, is that the dendritic vaccine "was not very immunogenic. We have a long way to go to optimizing this vaccine." Current studies are underway to test a new version of the vaccine, which utilizes more mature dendritic cells and tumor lysate in lieu of the translocation peptides. Ultimately, effective immunotherapy requires that one is capable of repr
|Contact: Jeremy Moore|
American Association for Cancer Research