An experimental vaccine may help colorectal cancer patients battle the disease. This vaccine developed in the U.K. stimulated the production of killer T cells in up to 70 of colorectal cancer patients.

Researchers at the University of Nottingham cloned an antibody called 105AD7 from a patient with colorectal cancer who survived seven years with liver metastases.

“This is the first vaccine shown to stimulate TNF-alpha — an immune system protein that is very effective at killing cancer cells,” says senior author Professor Lindy Durrant, from the University of Nottingham in England.

The study involved 67 patients, average age 66, with colorectal cancer of varying severity. They were randomized to receive 100 mcg of 105AD7, 105AD7 with BCG (a bacteria used to stimulate the immune system in cancer patients) during the first immunization followed by 105AD7 alone, or no treatment.

Around 70 percent of patients responded to the vaccine, which increased the production of an immune system protein called TNF-alpha. TNF-alpha stimulated the production of killer T cells, which produced cancer-destroying immune proteins called cytokines. Survival rates were not studied.

“This is very unusual, as most patients die within one year of getting liver metastases,” reported Durrant. “I thought if this antibody had helped this patient if we could clone it — it might help others.”

Patients were immunized before surgery on the day they started the study and again two weeks later if they had not had the surgery yet. The vaccines were also given at three, six, and 12 weeks after surgery, then at three monthly intervals for up to two years. Lab tests show most of the patients had a T-cell response against the vaccine.

The study appears in the November 15 issue of Clinical Cancer Research.