Therapy Analysis - Anticancer drugs
Where are we now?
In 1971, in response to pressure from the American people, President Nixon
announced a 'War on Cancer'. He requested an additional US$100m budget for
cancer research and converted the Army's Fort Detrick biological warfare facility
into the Frederick Cancer Research and Development Center, now internationally
recognised for its cancer and AIDS research. He also signed the National Cancer
Act, to cement his intentions. This took place against a backdrop of the early
stages of the war in Vietnam, successful space exploration, and scientific
breakthroughs such as splitting the atom. At that time, it perhaps did not seem
unreasonable to take on 'The Big C', and Nixon himself saw it as potentially being
his great lasting legacy. However, in so many ways, events were to prove him
wrong. After a further 30 years of research, how far have we come in conquering
one of the greatest causes of human death?
Approximately 12.5 million cases of cancer
are diagnosed each year worldwide, and
this figure is rising. In the UK, between
1975 and 2004, the overall cancer
incidence rate increased by 25%. This
partly correlates with lifestyle trends such
as changes in the rates of smoking and
obesity, but also with improved diagnosis
and a dramatic increase in the aging
populations of developing countries.
The global oncology market is currently estimated to be worth approximately US$42bn. While there are 2292 anticancer products currently reported to be in development, only a fraction of these will reach the market. Some estimates place around 37% of the preclinical candidates currently in development as expected to fail before or at the clinical stage. Given the costs of research and development, it is clear that while the rewards are high, so are the risks.
There are two key aspects to cancer cells, the ability to reproduce indefinitely by evading programmed cell death, and the ability to invade and colonise areas of the body populated by different cell types. A series of rigorous cell cycle controls normally regulate cell proliferation. If these fail, a cell can continue to grow and divide whether or not it is required. If this cell's progeny inherit the ability to escape cell cycle controls, they will go on to indefinitely produce clones. These abnormally proliferating, or neoplastic cells, can cluster into a benign tumour. A tumour is considered to be cancerous when it displays the second key aspect of tissue invasion, becoming malignant and spreading throughout the body, most often via blood or lymphatic systems, to establish secondary tumours.
