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Cancer survival rates have improved very significantly in many countries
over the last decade. Principally because of much better chemotherapy
but many of those chemotherapies have appalling side effects.
So what we need, urgently, are powerful forms of chemo,
which can be targeted to the individual cell
without affecting healthy cells. Scientists
working in a laboratory have been able to engineer
a human virus, which only infects, cancer cells.
It exploits a particular weakness of every cancer cell that we have studied so far
that produces tumours, and does not have the capacity to infect normal
tissue.
The side effects seem to be minimal
in human trials, so far. The commonest is
a slight flu-like illness for 24 hours but only a minority people even seem to
have that.
So it's essentially a treatment without serious side effects.
We've been able to load an additional instruction inside these virus
particles,
so that the cells that they infect, are taught, not only to make new virus particles but
also to make
chemotherapy. You say, 'Well, how can that be?' You see, scientists have created a molecule,
called a 'pro-drug' because it's not an active drug
itself. It's a drug that's protected in the blood. It doesn't
actually have any chemical effect. So you can give it
to the person and healthy tissue is not affected at all.
But inside the cancer cell, there is effectively a pair of scissors,
a pair of scissors that's been created by, built by
the genes of the virus. A pair of scissors which can split
that pro-drug into two fragments. And when that happens,
right inside the heart of that cell,
is released a very toxic of alkylating agent,
it's a chemo which destroys the cell from the inside.
And that toxic chemo,
is being delivered in such a microscopic dose, that even if, all it were to leak into the
blood,
it wouldn't really have any significant effect on the rest of the body.
But, if an individual cancer cell dies,
it sprays, not only its neighbors with more
virus particles but also releases molecules
of these toxic chemo, right in the very heart of that tumour mass,
giving an extra killing effect, just where you need it.
So this is an ingenious technology, a smart
technology. It's completely unlike the kinds of cancer chemotherapies that most
people with cancer have to take.
It can be used, almost certainly, alongside
other kinds of treatments like radiotherapy or traditional chemo
or at surgery, and so on.
But it has the power, the potential, to transform the way
that cancer is manager. Indeed, it is my conviction
that oncolytic virus' represent
the biggest scientific breakthrough potentially, that we have seen
in the management of Cancer, for over 30 years.