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Published by
 Australian Academy of Science
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Biology meets industry genomics, proteomics, phenomics
Box 2 | Case study Remicade and Glivec
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Glivec is a molecularly targeted drug treatment for chronic myeloid leukemia
(CML), manufactured by the pharmaceutical company Novartis. It operates
by blocking the specific signal
transduction pathway that is abnormally activated in leukemic cells.
Blocking the pathway prevents the uncontrolled proliferation of white
blood cells that characterises the deadly cancer. A primary difference
between Glivec and more conventional forms of cancer treatment such as
radiotherapy and chemotherapy is that Glivec specifically targets the
defective pathway which causes the disease. Radiotherapy and chemotherapy
are toxic to all the body's tissues, but are effective cancer treatments
because fast-dividing cancer cells are more susceptible than normal healthy
cells. However, the toxicity to healthy cells results in serious side-effects
for the patient.
Research into a
targeted treatment for the cancer was made possible when researchers at the
California Institute of Technology in the 1980s discovered that a single
defective protein (a tyrosine kinase enzyme) could cause CML this made it a
potential candidate for a targeted treatment. By the mid-to-late 1990s,
researchers had developed from a promising but weak-acting inhibitor class of
molecules a powerful, specific inhibitor that could inhibit the abnormal cell
pathway. Glivec has proven to be a very effective treatment for the disease,
and trials are underway to determine its effectiveness against other forms of
cancer.
A primary drawback to the treatment is its cost a year's treatment
with Glivec costs around $50,000. The drug is listed under the Commonwealth
Government Pharmaceutical Benefits Scheme in Australia, making it affordable
for sufferers. It was first approved for subsidy in 2001 for some patients
with CML. Coverage has since been expanded, and Glivec is now subsidised
as a first-line treatment against the early, chronic stages of CML.
Remicade is a drug designed to treat certain autoimmune diseases, especially
rheumatoid arthritis and Crohn's disease. It uses monoclonal antibody
technology to produce a specific antibody (patented by Australian biotech
company Peptech). The antibody blocks the action of the protein Tumour
Necrosis Factor Alpha (TNF-α). TNF-α is a powerful regulator of the
body's inflammatory immune response which is overproduced in sufferers
of rheumatoid arthritis and other auto-immune diseases. Remicade was registered
in Australia in August 2000, but was denied listing on the PBS until November
2003. While slightly less expensive than Glivec (at $20,000 per year)
there are more sufferers, and the total cost to the PBS is higher. The
delay in approving subsidy of the drug is illustrative of the difficult
decisions government bodies will have to make about these new technologies
especially in weighing up expensive treatments that, while not
life-saving, can have a tremendous impact on a patient's quality of life.
Related site
- Glivec
(Imatinib) (transcript of The Health Report, 21 July 2003,
Australian Broadcasting Corporation)
Other boxes
Box 1. Unveiling the proteome
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