This appears to be promising because it provides a protocol that
allows the agent to be safely transported to its target in order to
conduct its attack on the cancer cell. In this particular case, the
immune response against the cancer is also triggered which is a far
cry from strategies that merely suppress the immune system while
attacking the cancer cells generally. This obviously promises to be
way more effective.
It is a strategy that could wrestle a cancer into a controlled
situation even if it fails to end the cancer. Most approaches are
stuck with a do or die attack with cancer recovery a common
complication.
Thus an attack directly on the cancer that simultaneously boosts the
immune system response is much to be desired. Most other diseases do
exactly this when we step in to support the fight.
Hopefully it is flexible enough to be used against all cancers.
‘Hitchhiking’
Viral Therapy Deals a Double Blow to Cancer
Newswise —
Scientists have shown how a promising viral therapy that delivers a
double blow to cancer can sneak up on tumors undetected by hitching a
ride on blood cells.
The work, led by
researchers from the University of Leeds and The Institute of Cancer
Research (ICR), reveals how the ‘hitchhiking’ virus is shielded
from antibodies in the blood stream that might otherwise neutralize
its anti-cancer properties.
The findings, from a
study in patients, suggest that viral therapies like this can be
effectively injected into the bloodstream during routine outpatient
appointments - just like standard chemotherapy agents – making them
potentially suitable for use against a wide range of cancers.
Reovirus is a
promising new way of treating cancer that attacks the disease on two
fronts. Not only does the virus kill cancer cells directly, but it
also triggers an immune response - like a vaccine – that helps
eliminate residual cancer cells.
Many patient trials of
reovirus are currently underway, including several in the UK led by
the same University of Leeds and ICR scientists. Up until now,
however, doctors have not been sure about the best way to deliver the
experimental treatment. Although the virus can be injected directly
into tumors, this is a relatively complicated procedure requiring
considerable technical expertise. This delivery method also makes it
difficult to treat tumors deep within the body, such as the liver,
lungs, pancreas, and stomach.
Researchers had been
concerned that reovirus might not reach the tumors it was supposed to
treat if it was delivered intravenously, like standard chemotherapy
agents are. They had expected that antibodies in the blood would mop
up and neutralize the virus before it arrived at its intended target.
But now tests on a
small group of patients have shown that this is not the case. In
fact, not only did the virus stay active during its journey through
the bloodstream but it also homed in on cancer cells, ignoring nearby
healthy tissue.
University of Leeds’
researcher Professor Alan Melcher, who receives funding from Cancer
Research UK, jointly led the study. He said: “It seems that
reovirus is even cleverer than we had thought. By piggybacking on
blood cells, the virus is managing to hide from the body’s natural
immune response and reach its target intact. This could be hugely
significant for the uptake of viral therapies like this in clinical
practice.”
Dr Kevin Harrington
from The Institute of Cancer Research and The Royal Marsden NHS
Foundation Trust, who jointly led the study, said: “Viral
treatments like reovirus are showing real promise in patient trials.
This study gives us the very good news that it should be possible to
deliver these treatments with a simple injection into the
bloodstream. It would have been a significant barrier to their
widespread use if they could only have been injected into the tumor,
but the finding that they can hitch a ride on blood cells will
potentially make them relevant to a broad range of cancers. We also
confirmed that reovirus was specifically targeting cancer cells and
leaving normal cells alone, which we hope should mean fewer
side-effects for patients.”
The study involved 10
patients with advanced bowel cancer who were due to have surgery on
tumors that had spread to the liver. All patients were given up to
five doses of the reovirus in the weeks before surgery as
outpatients.
Blood tests carried
out shortly after treatment found the active virus associated with
blood cells. Samples taken later showed that the hitch-hiking virus
did not overstay its welcome with the cells and was cleared quickly
from the system.
When researchers
looked at pieces of tissue removed during surgery up to four weeks
later, they found ‘viral factories’ and active virus in the
tumor, but not normal liver. This confirmed that the reovirus had
been delivered specifically to the cancer after being injected into
the bloodstream.
Dr Julie Sharp, senior
science information manager at Cancer Research UK, which part-funded
the research, said: “This promising study shows that reovirus can
trick the body’s defenses to reach and kill cancer cells and
suggests that it could be given to patients using a simple injection.
We look forward to seeing how this research develops and if this
could one day become part of standard cancer treatment.”
Full details of the
work are published today in the journalScience Translational
Medicine. The paper covers findings from the U.K. translational
clinical trial (REO 013) investigating intravenous administration of
REOLYSIN (Oncolytics Biotech) in patients with metastatic colorectal
cancer prior to surgical resection of liver metastases.
The work was funded by
Cancer Research UK, Leeds Experimental Cancer Medicine Centre,
University of Leeds, The Institute of Cancer Research, Leeds Cancer
Vaccine Appeal, and the Rays of Hope Appeal.
Further information:
Professor Alan Melcher
is available for interview.
Notes for Editors
1. The paper: Adair,
RA, "Cell Carriage, Delivery, and Selective Replication of an
Onocolytic Virus in Tumor in Patients," is available to
journalists at http://www.eurekalert.org/jrnls/scitransmed/.
Alternatively, please contact the Science press office on +1
202-326-6440 or scipak@aaas.org.
2. One of the UK’s
largest medical, health and bioscience research bases, the University
of Leeds delivers world leading research in medical engineering,
cancer, cardiovascular studies, epidemiology, molecular genetics,
musculoskeletal medicine, dentistry, psychology and applied health.
Treatments and initiatives developed in Leeds are transforming the
lives of people worldwide with conditions such as diabetes, HIV,
tuberculosis and malaria. www.leeds.ac.uk
3. The Institute of
Cancer Research (ICR) is one of the world’s most influential cancer
research institutes. Scientists and clinicians at the ICR are working
every day to make a real impact on cancer patients’ lives. Through
its unique partnership with The Royal Marsden Hospital and
‘bench-to-bedside’ approach, the ICR is able to create and
deliver results in a way that other institutions cannot. Together the
two organisations are rated in the top four cancer centres globally.
www.icr.ac.uk and
www.royalmarsden.nhs.uk
The Royal Marsden NHS
Foundation Trust
The Royal Marsden opened its doors in 1851 as the world’s first hospital dedicated to cancer diagnosis, treatment, research and education. Today, together with its academic partner, The Institute of Cancer Research (ICR), it is the largest and most comprehensive cancer centre in Europe treating over 44,000 patients every year. It is a centre of excellence with an international reputation for groundbreaking research and pioneering the very latest in cancer treatments and technologies. The Royal Marsden also provides community services in the London boroughs of Sutton and Merton and in June 2010, along with the ICR, the Trust launched a new academic partnership with Mount Vernon Cancer Centre in Middlesex. www.royalmarsden.nhs.uk
4. Cancer Research UK
is the world’s leading cancer charity dedicated to saving lives
through research. The charity’s groundbreaking work into the
prevention, diagnosis and treatment of cancer has helped save
millions of lives. This work is funded entirely by the public.Cancer
Research UK has been at the heart of the progress that has already
seen survival rates in the UK double in the last forty years. Cancer
Research UK supports research into all aspects of cancer through the
work of over 4,000 scientists, doctors and nurses. Together with its
partners and supporters, Cancer Research UK's vision is to beat
cancer.For further information about Cancer Research UK's work or to
find out how to support the charity, please call 0300 123 1861 or
visit www.cancerresearchuk.org.
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5. Oncolytics Biotech
Inc.
Oncolytics is a Calgary-based biotechnology company focused on the development of oncolytic viruses as potential cancer therapeutics. Oncolytics’ clinical program includes a variety of human trials including a Phase III trial in head and neck cancers using REOLYSIN, its proprietary formulation of the human reovirus. For further information about Oncolytics, please visit: www.oncolyticsbiotech.com
Professor Alan Melcher
is available for interview.
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