Great news for us from C3

Patients’ Own Tumor Cells Make Effective Cancer Vaccine
Posted: 30 Nov 2010 07:36 AM PST
Written by Kate Murphy.

dendritic immune cell
Doctors at Dartmouth-Hitchcock Medical Center in New Hampshire have built personalized cancer vaccines that use the patient’s own immune system to fight colorectal cancer.
The key to success was first removing bulky liver tumors and then using the vaccine to kill any tiny cancers remaining in the body.
Five years after getting the vaccine, two-thirds of patients whose systems produced an immune response to the vaccine were alive and cancer free.
Following surgery to remove colorectal cancer that had spread to the liver, patients received a vaccine, made just for them, that combined dendritic cells from their blood with protein from their tumor.
Dendritic cells are part of the immune system. Their role is to recognize foreign bodies, such as viruses or bacteria, and trigger a response from other immune cells that surround and destroy invaders. However, since cancers are not recognized as “foreign”, they aren’t easily attacked by the immune system.
A goal of cancer research has been to trick the immune system into seeing cancers as targets to be destroyed. But previous dendritic cell research hasn’t been successful in reducing large tumors.
Dr. Richard Barth, Jr., the Dartmouth surgeon whose team developed the vaccine, thinks he knows why.
It turned out we were asking the T-cells to do too much. The small number of T-cells that are generated by a vaccine can’t destroy a large tumor. However, what they may be able to do is search out and destroy tumor cells that exist as only microscopic tumor deposits. Once we brought patients into a measurable tumor-free condition with surgery, the anti-tumor T-cells induced by the DC vaccine may help keep them that way.
Dr. Barth operated on 24 colorectal cancer patients to remove tumors that had spread to their livers. About a month later they received the vaccine. Fifteen of those patients (63 percent) had an immune response to the vaccine.
The patients who showed immune response were much more likely to be alive and cancer-free five years after treatment. Sixty-three percent (63%) of them had not had cancer return compared to only 18 percent of those who didn’t have a response.
The vaccine is non-toxic, compared to chemotherapy, which may have serious side effects. Talking about the future of dendritic cell research, Dr. Barth said,
It’s your own immune system doing the fighting. I’m optimistic that this really will have an impact.
SOURCE: Barth et al., Clinical Cancer Research,Volume 16, Number 22, November 15, 2010.