Fed: Cancer vaccine hope as trial begins

AAP General News (Australia)
04-13-2004
Fed: Cancer vaccine hope as trial begins

By Kylie Walker, National Medical Correspondent

MELBOURNE, April 13 AAP - Prostate cancer patients are being given the chance to trial
a new vaccine designed to trick the immune system into killing cancer cells.

Cancer Trials Australia doctors at three clinics - the Austin Hospital, Royal Melbourne
Hospital and Peter MacCallum Cancer Centre - are recruiting 40 patients to receive eight
injections of the vaccine over six months.

Trial leader, Associate Professor Ian Davis of the Austin Hospital, said the team hoped
the phase II trial would show the Pentrix vaccine prompted tumours to shrink.

"It's a way of tricking the immune system into responding to a substance called p53,
which accumulates abnormally in various types of cancer including prostate cancer," Assoc
Prof Davis said.

"The idea is that if it were possible to get a useful immune response against this
substance, and you could teach the immune system to recognise this, ... the immune system
would attack this substance and kill it."

Animal trials of the vaccine have had good results but in a human trial conducted a
couple of years ago, Pentrix failed to cause cancers to shrink or prompt an immune response
against p53.

Despite the lukewarm result, the company behind the vaccine, Australian Cancer Technology,
said their product still had merit, and the scientists said they were willing to put it
to the test.

"There's enough science behind this to say that it's a reasonable idea, that it's possible
that we might be able to get the immune responses we're looking for," Assoc Prof Davis
added.

"To get a clinical benefit as a result of that is a couple of steps beyond that point,
it may or may not give us that.

"I guess the bottom line is, there's enough reason to study it and to think it's a
worthwhile idea, and until we've done the trial we won't know if it's of any benefit or
not."

Men being recruited for the new trial have prostate cancer that's progressing despite
hormone treatment.

"The aim is firstly to see if it's safe in this patient group - we fully expect that
it will be - secondly, is it now possible to detect an immune response against the p53
rather than the vaccine itself," Assoc Prof Davis said.

"Thirdly, is it possible to get some sort of clinical response."

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KEYWORD: VACCINE

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