A new era in cancer therapy could be opened
later this year with the launch of a vaccine which tackles the disease in a
new way and could spell the end of chemotherapy.
Melacine is the first cancer vaccine which
has been developed as a treatment for advanced melanoma, the most aggressive
form of skin cancer which claims 2,000 lives a year in the UK. The drug is
expected to win approval from the US Food and Drugs Administration within
the next six months after trials in patients showed ‘promising’ results.
A further five or six cancer vaccines are in
the pipeline and are expected to be launched within the next two years. Some
experts predict that they could spell the end of chemotherapy: treatment
with large doses of toxic drugs whose effects can be worse than the disease:
and usher in kinder therapies for people with cancer.
Cancer vaccines are so called because they
work by harnessing the body’s immune system to fight the disease. They
differ from conventional vaccines because they are given as a treatment
rather than to prevent disease.
They are the first new class of drugs for
cancer in a decade since the taxanes were developed in the late 1980s. These
include the drugs Taxol, for advanced ovarian cancer, which is derived from
the bark of the Pacific yew tree and Taxotere, for advanced breast cancer.
Melanoma is the first cancer for which
researchers have identified antigenic molecules on the surface of the cancer
cells which act as a trigger for the immune system. Melacine, made by the US
biotechnology company Ribi Immunochem, is one of a number of vaccines being
developed for melanoma which primes the immune system to recognize the
molecules and boosts the immune response to destroy cancer cells.
Professor Angus Dalgliesh, Director of the
Gordon Cancer Vaccine Laboratory at St George’s Hospital, London, said:
“Cancer vaccines may well take over from chemotherapy. They will probably
knock out chemotherapy.” He said: “Where cancer vaccines are going to work
is in cases where a solid tumor is removed and there is a high chance of the
cancer coming back. They are the people who will get the vaccine to kick
start the immune system. In most cases it will only delay the inevitable but
if you can do that with a non-toxic treatment that will be a valuable
Rejoinder by Dr. Kothari and Dr. Mehta
The above report makes two things
clear: (a) The cancer world is tired of chemotherapy, and, (b) Vaccines may
replace chemotherapy as a curative measure. This will be for the first time
that a vaccine will be used not as a preventive measure, but as a curative
snag about the vaccine promise is that it is unlikely to work for 2 reasons:
(a) No two cancers, even in the same individual, have ever been alike. Which
means you must have a specific vaccine against a specific cancer. Which
means you allow a cancer to develop fully, then set about making a vaccine,
and then administer it to now kill the cancer. But any given cancer has
multiple clones. If the vaccine misses one, then by natural selection, that
clone will exert its might to recreate the original mass of the cancer. (b)
Supposing the vaccine is effective against all the possible clones that a
cancer exhibits, the 100% cancer kill cannot prevent neocanceration of the
next normal cell that is waiting to turn cancerous.