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There seems little doubt
that the 21st century will see significant advances in the
treatment of cancer. The high level of investment in the
development of innovative cancer drugs, using the wealth
of information being generated in the biotechnology sphere,
is likely to result in profound improvements in the ways
in which cancer is treated, as well as huge opportunities
for the pharmaceutical and biotech companies involved.
This new generation of cancer therapies, led by Roche/Genentech's
already marketed monoclonal antibodies, Herceptin and MabThera/Rituxan,
looks set to revolutionise the global cancer market over
the next few years.
Unlike most currently available cancer therapies, which
can result in severe toxic effects on normal tissue when
used at the dosages necessary to kill tumour cells, the
innovative new drugs target particular aspects of the disease,
which tends to restrict tissue destruction to the tumour
itself.
For instance, monoclonal antibodies (MAbs) work because
of their unique specificity for tumour-associated antigens,
based on the differences in cell surface protein expression
between cancerous and normal tissues. Because many different
types of tumour can express an antigen that normal tissues
do not, one type of MAb can have potential for many different
types of cancer.
MAbs have been described as "magic bullets", which attack
specific tumour cells, sparing normal cells from exposure
to a cytotoxic agent.
MabThera/Rituxan (rituximab) and Herceptin (trastuzumab)
are the first such treatments to become available, and have
generated encouraging sales in their first few years on
the market, particularly in the USA.
Genentech's Rituxan (developed by IDEC Pharmaceuticals),
a treatment for non-Hodgkin's lymphoma launched in the USA
at the end of 1997, recorded sales of $279.4 million in
1999, an increase of 71.8% over $162.6 million in 1998.
The product has already generated sales of $305.8 million
for Genentech, which is majority-owned by Roche, in the
first nine months of 2000, and has become one of the leading
cancer therapies in the world in terms of sales.
Herceptin, a treatment for breast
cancer launched in the fourth quarter of 1998, looks
on course to be just as successful, with sales of $188.4
million for Genentech in 1999, its first full year on the
market, making it the most successful cancer product launch
ever in the USA. Genentech reported Herceptin sales of $208
million in the first nine months of 2000.
Although over 90% of sales of rituximab and trastuzumab
are generated in the USA, the products are taking an increasing
share of the total global market for cancer products, which
grew by 20% in 1999, according to IMS HEALTH's World
Review 2000. The potential for geographic growth for
the products is clear, particularly given the August 2000
approval of Herceptin in the EU.
As a direct result of the success of its subsidiary Genentech's
two MAb products, Roche was the number two corporation in
the L1X, or "All Other Cytostatics", ATC class in World
Review 2000, with 29% of the market, after Bristol-Myers
Squibb (BMS) with 51%.
Source: IMS HEALTH World
Review 2000
In addition, Roche was one of just three of the top ten
companies in ATC L (which covers cancer treatments) to increase
its share of the market in 1999. The other two companies
were Schering-Plough and Biogen, whose share of the class
grew solely because of increased sales of their interferon
products, which are used mainly for the treatment of multiple
sclerosis rather than cancer.
The September 2000 announcement of a strategic alliance
between Roche and BMS, aimed at accelerating combination
trials of Herceptin and BMS' Taxol (paclitaxel), the leading
cancer treatment in the world, is likely to provide a further
boost to future sales of Herceptin.
According to IMS HEALTH's R&Dfocus,
there are over 1,000 innovative cancer treatments in the
R&D pipelines of the world's pharmaceutical and biotechnology
companies. Many different approaches are being used to target
the tumours.
AstraZeneca's Iressa
(ZD 1839), for instance, targets the epidermal growth
factor (EGF) receptor, which tumours use to survive and
grow. Iressa is a key element in AstraZeneca's stated objective
of becoming the leading oncology company by 2010, and some
analysts have predicted peak sales of over $1bn. The FDA
has given Iressa fast track status and regulatory submissions
are due late in 2001.
Yet another approach is that of gene
therapy, an area of research that has promised much
but has yet to deliver. The majority of current gene therapy
projects are focused on oncology and, furthermore, gene
therapy projects make up the largest proportion of innovative
R&D in the cancer arena.
R&Dfocus now lists 12 gene therapy projects in Phase III
clinical trials for the treatment of cancer, and so products
based on this technology can be expected to reach the market
within the next few years.
Perhaps unsurprisingly, given the clear commercial success
of rituximab and trastuzumab, monoclonal antibodies are
being used in the bulk of innovative cancer drugs in late
stage development.
There are currently around 30 MAb-based cancer drugs in
development at Phase III or above. In contrast to the two
Roche/Genentech products, many of the drugs in development
use the MAbs simply to target the tumour. In these cases,
the MAb is labeled with a chemotherapeutic or radioactive
compound, which does the damage at the tumour site.
One example is Antisoma's potential ovarian cancer treatment,
Theragyn (pemtumumab), which is labelled with the radioisotope,
yttrium-90. Theragyn survived a recent report by an independent
researcher that cast doubts on its efficacy, and Phase III
clinical trials were resumed in May 2000.
Source: IMS HEALTH R&Dfocus
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