http://www.thaindian.com/newsportal/...100209241.html
London, June 25 (ANI): A new drug has shown promise in providing
protection to individuals who were genetically vulnerable to developing
cancers, say British researchers.
People carrying BRCA1 or BRCA2 mutations are an increased risk of
developing cancer. It weakens the ability of a person’s cells to repair
themselves.
While the risk of developing prostate cancer in men doubles from 7pct to
more than 15pct, women’s chances of getting ovarian cancer increases from
2pct to 60pct.
Their chances of getting breast cancer also leaps from 10pct, to as much
as 85pct.
The new drug called Olaparib - developed by the Institute of Cancer
Research (ICR) in collaboration with The Royal Marsden Hospital and
AstraZeneca - has been found to prevent malignant cells from repairing
themselves.
Through this study, the researchers say, they have found a novel way of
exploiting a fault inherent in BRCA mutation cancer cells to destroy them.
“By giving this drug we have made what has been an advantage to the cell
in fact an achilles heel,” Sky News quoted Dr Johann de Bono, of the
Institute of Cancer Research (ICR) as saying.
“This is really the holy grail of cancer treatment - selectively killing
cancer cells and sparing normal cells,” de Bono added.
Traditional cancer treatments, like chemotherapy, kill both healthy and
cancerous cells, however, Olaparib leaves healthy cells untouched. (ANI)
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Other Sources
Olaparib works differently than other cancer drugs in that it blocks
Poly(ADP-ribose) polymerase (PARP), a protein involved in DNA repair.
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http://news.bbc.co.uk/2/hi/health/8116790.stm
New cancer drug 'shows promise'
Breast cancer cells
The treatment was tested on breast cancer patients
Researchers say a new type of cancer treatment has produced highly
promising results in preliminary drug trials.
Olaparib was given to 19 patients with inherited forms of advanced breast,
ovarian and prostate cancers caused by mutations of the BRCA1 and BRCA2
genes.
In 12 of the patients - none of whom had responded to other therapies -
tumours shrank or stabilised.
The study, led by the Institute of Cancer Research, features in the New
England Journal of Medicine.
CASE STUDY
Julian Lewis
Julian Lewis, 62, was treated with olaparib after being diagnosed with
advanced prostate cancer.
Within a month or two levels of a key chemical marker of cancer went down
to a low level, and have now stayed low for more than two years.
In addition, secondary tumours in his bones have almost disappeared.
He has experienced minor side-effects, such as stomach discomfort and mild
nausea, but he said: "I hope to carry on with this for as long as
possible.
Partly the aim is the obvious one of keeping my cancer cells in check, but
there's a broader goal too: to help find out how long this drug can be
used safely in other people."
One of the first patients to be given the treatment is still in remission
after two years.
Olaparib - a member of a new class of drug called PARP inhibitors -
targets cancer cells, but leaves healthy cells relatively unscathed.
The researchers, working with the pharmaceutical company AstraZeneca,
found that patients experienced very few side-effects, and some reported
the treatment was "much easier than chemotherapy".
Researcher Dr Johann de Bono said the drug should now be tested in larger
trials.
He said: "This drug showed very impressive results in shrinking patients'
tumours.
"It's giving patients who have already tried many conventional treatments
long periods of remission, free from the symptoms of cancer or major
side-effects."
Olaparib is the first successful example of a new type of personalised
medicine using a technique called "synthetic lethality" - a subtle way of
exploiting the body's own molecular weaknesses for positive effect.
In this case the drug takes advantage of the fact that while normal cells
have several different ways of repairing damage to their DNA, one of these
pathways is disabled by the BRCA mutations in tumour cells.
Olaparib blocks one of the repair pathways by shutting down a key enzyme
called PARP.
BRCA MUTATIONS
BRCA1 or BRCA2 mutations weaken the cells' ability to repair DNA damage
They are thought to be responsible for about 5% of breast and ovarian
cancers, and about 1-2% of early onset prostate cancers
Women with a BRCA mutation have a risk of up to 85% on breast cancer, and
up to 60% on ovarian cancer
Men with a BRCA mutation have a risk of up to 15% on prostate cancer
This does not affect normal cells because they can call on an alternative
repair mechanism, controlled by their healthy BRCA genes.
But in tumours cells, where the BRCA pathway is disabled by genetic
mutation, there is no alternative repair mechanism, and the cells die.
Cancer cells with the BRCA1 or BRCA2 mutations are the first to be shown
to be sensitive to PARP inhibitors.
But there is evidence that olaparib will also be effective in other
cancers with different defects in the repair of DNA.
Professor Stan Kaye, who also worked on the study, said: "The next step is
to test this drug on other more common types of ovarian and breast cancers
where we hope it will be just as effective."
The researchers say the process of drug evaluation and registration may
have to be revamped to take consideration of the fact that new generation
cancer drugs target specific molecular defects, rather than types of
cancer.
Dr Peter Sneddon, of the charity Cancer Research UK, said: "It is very
encouraging to see the development of 'personalised treatment', tailored
to the requirements of the individual patient, becoming a reality as it
offers the opportunity to design new drugs that are truly selective.
"Although development of this drug is in its early stages, it is very
exciting to see that it has the potential to work when other treatment
options have failed."
=?iso-8859-1?Q?=91Space=20Age=92?= cancer drug shows promise 
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