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New Zealand and Australia have long been united in their beach-loving, sun-worshipping ways - and in their top rankings in the world's melanoma ratings.
Now they have been linked in a trial of how to beat the disease with a vaccine made with cancer patients' own tumours.
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The Malaghan Institute of Medical Research has joined the Wellington Blood and Cancer Centre and the Queensland Institute of Medical Research to test the effectiveness of a personalised vaccine. The phase three trial - an advanced stage of testing which compares a new drug with standard treatments - will involve 200 patients who have had a melanoma removed and in whom the disease has spread to a lymph node.
A small trial of 12 patients run previously by the Queensland institute found that three had no noticeable tumour after treatment, the tumour shrank in three and six had no response.
Malaghan vaccine research group leader Ian Hermans says it is normal for melanomas to shrink sometimes.
"But this seems to be quite remarkable - three out of 12, you wouldn't see that number spontaneously regress. The feeling is this is a real response to the vaccine, which is the justification for going for such a big study."
Melanoma is New Zealand's third most common cancer, starting mainly on the skin. If detected early, it is readily treated by surgery; if not, it can spread to organs and be fatal.
Most patients with a thin melanoma will be alive 10 years after detection and treatment but 60 per cent of those with a tumour more than 4mm thick when diagnosed will have died.
If melanoma becomes malignant, fewer than 5 per cent survive five years.
Chemotherapy and radiation therapy are sometimes used after surgery when the cancer has spread. However, they are of little proven benefit, says a September NZ Medical Journal article, adding Interferon increased survival but had severe side effects.
The personalised vaccine developed by Malaghan is made specially for each patient using material from his or her body. It mixes a type of immune system cells, called dendritic cells - isolated from a blood sample - with dead tumour cells.
First, part of the tumour is surgically removed then sent to Malaghan's vaccine laboratory, where it is broken down into cells, which are then killed by radiation.
Those cells are mixed with the dendritic cells to form a vaccine that is injected 13 times over more than two years.
The primed dendritic cells go to lymph nodes, where they pass on information about how to identify cancer cells by a protein on their surface. Armed with this molecular identikit picture, immune system T cells proliferate, seeking out cancer cells and killing them.
Dr Hermans said none of the debilitating side effects of chemotherapy occurred with this vaccine. "That's the beauty of immunotherapy, dendritic cell therapy in particular: no one has shown adverse effects other than mild flu-like symptoms after the vaccine."
The Queensland institute used a similar method but used whole killed cells rather than cancer cell protein fragments.
Malaghan - which has been researching dendritic cells in cancer for more than a decade - has also run a small trial of its own version of personalised vaccine against another type of cancer, non-Hodgkins lymphoma. It showed a positive clinical response in two of the 10 patients.
Dr Hermans said there was a "huge international effort" researching dendritic cells in cancer.
"Fifteen years ago, the significance of dendritic cells' capacity to stimulate an immune response was realised. Everyone immediately latched on to exploring the power of these cells. In immune research, it's the most studied cell at the moment - in a variety of cancers. You name it, they've tried it."
In related research, Malaghan scientists have investigated a skin cream containing cancer cell proteins. It is based on the same idea of loading the proteins on to dendritic cells, which are present in the skin as well as the blood. The cream was found to activate T cells that could then recognise and attack the tumour.
Looking at other cancers, Malaghan is seeking finance to start a phase 1 trial ( testing doses and possible side effects) of treating brain tumour patients with a personalised vaccine plus chemotherapy.
At Auckland University, researchers have recruited melanoma patients to trial a single vaccine that could be suitable for many patients, unlike Malaghan's personalised vaccine. The phase 2 trial of the vaccine, developed by the international Ludwig Institute for Cancer Research, is being run here, Australia and Britain.
The vaccine contains a cancer protein, called NY-ESO-1, produced by about 40 per cent of melanomas. The protein is also found on some prostate, breast and other tumours and the vaccine is being tested against them in other trials. The vaccine is designed to prime T cells to recognise the protein on cancer cells and then kill them.
The melanoma trial will test whether the vaccine delays cancer coming back, after surgery, in patients at high risk of a recurrence. It will compare one group receiving the vaccine and an immune system booster, with another receiving just the booster.
The university's professor of oncology, Michael Findlay, said an earlier study of NY-ESO-1 vaccine comparing various doses suggested it could help.
"In that preliminary study, it looked like there was some advantage in terms of disease free survival with the top dose."
Another exciting approach to cancer is gene therapy, which is just starting to show success in a few patients. In September, the US National Cancer Institute said two of 15 patients given the treatment for malignant melanoma had been cleared of cancer cells.
Therapeutic and prophylactic weapons use body's immune system to prevent and fight cancer
Cancer vaccines are a relatively new addition to the field of immunotherapy, a large area of research that looks at harnessing the body's immune system to fight disease.
Therapeutic vaccines, such as the one being developed at the Malaghan Institute, aim to prevent cancer from recurring and may stop the growth of existing tumours.
Prophylactic vaccines, meanwhile, are given to healthy individuals before cancer develops. The best known example of the latter is Gardasil.
Although it has been touted as the world's first vaccine against cervical cancer, Gardasil is more accurately described as a human papilloma virus (HPV) vaccine. It protects against four strains of the virus - two of which are associated with 70 per cent of cervical cancer cases.
But Gardasil, which was made available in New Zealand in September, will not protect against all cervical cancers, as some are not caused by the HPV strains targeted by the vaccine. Routine Pap smears are still needed even for vaccinated women.
Like all vaccines, Gardasil works by introducing a benign or weakened form of the virus into the body. It contains virus-like particles assembled from the major proteins of the four HPV strains.
Since these particles lack viral DNA, they cannot induce cancer. But they will induce an antibody response that protects the vaccinated woman from becoming infected with the HPV-types in the vaccine.
- Errol Kiong
