Vaccines

This type of treatment is experimental. It is a type of biological therapy. These are treatments that use natural body substances, or inactivated melanoma cells, to treat cancer. Vaccine treatment is not yet widely available because it is still being tested. But we have included it here because a lot of people are interested in it and it gets quite a bit of press coverage.

There are two areas of research that vaccines are being used for:

  • As treatment for people with advanced melanoma that has spread to another part of the body
  • As adjuvant therapy for people with high-risk melanoma particularly where it has spread to the lymph nodes

Cancer vaccines are designed to try to stimulate the body's own immune system to fight the melanoma. The immune system does this by making antibodies to specific proteins (antigens) found on melanoma cells.

Antigens are large molecules found on all cells that the body recognises as foreign (in other words, not their own). Cancer cells have antigens. Antibodies are proteins made by the body that match each antigen exactly. The antibody combines with the antigen and marks that cell to be killed off by the immune system.

A cancer vaccine can either:

  • Be made individually with one person's melanoma cells and used to treat just that person
  • Be made using lots of different melanoma antigens from different melanomas and used to treat many people

Vaccines made individually contain all the antigens that come from that person's melanoma. Making it this way can be expensive and time consuming. But it is a good way of trying to make sure the vaccine works.

Other vaccines use several different strains of melanoma cells and have a large number of different antigens. Patients who have this vaccine will have some of the antigens on their melanoma cells and not others. This type of vaccine can be made in large quantities and can treat many people.

How is the treatment given?

Cancer vaccines are usually given as a small injection just under the skin. The vaccine has to be repeated often because the melanoma antigens do not stimulate the immune system for long. You may have a vaccination every week for a few weeks, and then two weekly, or monthly injections. The treatment is also given over a long period of time in some cases.

How long does it take to work?

Vaccines take longer to work than chemotherapy does. The immune response in the body can be measured by taking blood samples. Research shows that it takes up to 4 months for an immune response to take place. If the vaccine works, the rate of growth of the melanoma will then begin to slow down. Then it may become stable (not growing any more) for a while. Eventually, the melanoma may start to shrink.

How long does it go on working?

We don't have enough information at the moment to be sure. In early research studies, the response to the vaccine has lasted for months in some people, and for years in others. In some, it doesn't work at all. Researchers are not yet sure why it works in some people and not in others.

What are the side effects?

Apart from soreness at the place where the injection is given in some people, there do not appear to be many side effects. Some people have similar side effects to interferon, such as flu-like symptoms with a headache, aching and fever.

What are the results of the trials so far?

The trials that have been completed so far are phase 2 trials. This means it is early research designed to see whether the new treatment works at all. With early research, you should be wary of reading too much into the results. They could be biased because the trial was not randomised. Early results show that some people might do very well with the vaccine. Others show very little response to it at all.

People with advanced melanoma who have had vaccine treatment have had:

  • No response at all
  • Their cancer completely disappear
  • Some shrinking of their melanoma
  • Some slowing down of the rate of growth of their melanoma

Some of these patients had operations to remove their melanoma secondaries before having the vaccine. The operations were not done to cure the cancer. But the researchers think the vaccine might work better if there is less melanoma to fight.

Researchers also believe that their vaccine might help stop melanoma from spreading to new areas in the body by stimulating the immune system to kill off melanoma cells in the blood or tissues.

People with high-risk melanoma where the melanoma has affected the lymph nodes have also had a mixed response to vaccines. The vaccine may help stop the cancer coming back in some people, but not in others.

What is the future for this treatment?

More work will be done with cancer vaccines to treat melanoma. Doctors need to understand why the vaccine works in some people and not others. They are beginning to be able to see who will benefit and who won't by looking at the immune response in the first few weeks of treatment. If you have a good immune response, the vaccine is more likely to work for you. New research has begun, which is trying to stimulate an immune response by combining the vaccine with other triggers to the immune system such as the TB vaccine BCG.

Some phase 3 trials have taken place, but results so far have been disappointing. These trials compared vaccine treatments to either another type of treatment or no treatment. But research is continuing and the results from such trials will help us find out if this treatment really can help people with melanoma.

How do I find out about the trials?

First you must see whether you fit into the entry criteria for the trial you are interested in. This is very important. Trials have to select groups of patients in similar circumstances so that direct comparisons between new and established treatments can be made. They will not bend the rules.

If you don't meet the entry criteria, you can't be accepted onto the trial. For example, a trial protocol may ask that you:

  • Have a particular stage of melanoma
  • Are within a set age range
  • Do not have secondaries in certain organs (e.g. brain, bone)
  • Are at a certain point in your treatment

There are several research centres working on melanoma vaccines including New Zealand researchers. You should ask one of our Medical Oncologists if you want to know if vaccine treatment is possible.