Cancer 'vaccine' results encouraging

The "vaccine" may be able to help the body fight cancer

A "vaccine" which may stimulate the immune system to fight cancer has shown encouraging results in early trials.

The reason why cancer cells grow and flourish in the body is because the immune system does not recognise them as foreign, and leaves them alone.

Immunotherapy is designed to prime the immune system to identify the cancerous cells as invaders, and launch an attack.

This may either be able to destroy the tumours as a first line treatment, or "mop up" left-over cells which have survived surgery, radiotherapy or chemotherapy.

The latest "vaccine" tests were carried out on pancreatic cancer patients at Johns Hopkins University in Baltimore in the US.

The aim of the trial was to see if the treatment was safe, and whether it could provoke any sort of immune response from the patients.

It was tested on 14 patients who had already undergone surgery for pancreatic cancer, which has a relatively poor survival rate.

Highest dose worked best

All received varying doses of the "vaccine", and 12 then went on to have further radiotherapy and chemotherapy.

Researchers found that several different areas of the immune system were activated in patients given the highest doses.

The rest showed no significant immune response.

The three patients given the highest doses remain disease-free 30 months after treatment.

Professor Elizabeth Jaffee, associate professor of oncology at Johns Hopkins, conceded that the study was only a first step, especially as so few patients were given the highest dose.

But she added: "Genetically engineered vaccines like this could be used to 'mop up' microscopic cancer cells left behind following surgery, chemotherapy and radiation.

"We need to find the combination of these treatments that will afford patients the best chance of survival."

The next phase of trials starts this summer at Johns Hopkins.

The "vaccine" was created by adding a gene to pancreatic cancer cells in the laboratory.

Immune cells

This gene, called GM-CSF, is known to activate the immune system and attract immune cells.

The theory is that once the cells arrive, they will then recognise other chemicals on the surface of the cancer cells and note them as foreign.

When these chemicals are subsequently encountered in the real tumour, they will be recognised and the genuine cancer cells marked for destruction by the immune system.