Therapy Analysis - Anticancer drugs
Modern day anticancers
The development of biologically-based therapeutics has been a major turning point. Genetic and proteomic discoveries have identified a large number of potential targets, and thus corresponding therapies, and led to a boom in research alongside the traditional smallmolecule market. The aim of modern research is to increase targeting specificity and thus reduce the sideeffect profile. Theoretically, biological therapies provide a perfect opportunity to achieve this. By enhancing, mimicking or replacing components of the human body, these therapies can slip into already existing pathways unnoticed and with the least amount of disruption.
There has been a shift in anticancer research between 1990 and 2006 with an ever-increasing variety and number of biological therapeutics in development. There has also been an increase in cellular therapies, as well as a dramatic increase in synthetic peptide and antibody therapeutics for oncology treatment (graph 1 and 2).
One of the first biological therapeutics for cancer was the interferons, which act by slowing the growth of cancer cells or promoting their development into cells with a more normal behaviour. Some interferons also stimulate NK cells, T-cells and macrophages, thereby boosting the immune system's anticancer capacity. Interferon-a is the most widely-used interferon in cancer and was first tested in leukaemia, lymphoma, HIV-associated Kaposi's sarcoma and melanoma patients in the early 1980s. Interferon therapeutics have gone on to varied success, depending on the indication, due to a substantial side-effect profile. However, 27 interferons, including a range of formulations and recombinant versions of the proteins, have made it to through to launch.
A major area of development in recent years has been antibody-based technologies. Monoclonal antibodies, specific for a particular antigen, are especially relevant in this field, They not only allow specific targeting of cell components that are unusually upregulated or mutated, but are also naturally occuring and therefore create less disturbance upon introduction to the body.
Genentech's Herceptin (trastuzumab) is a classic and well publicised example of this. First launched in 1998, it targets and blocks the transmembrane Her2/neu growth factor receptor that is significantly upregulated in some breast cancers. This protein is constitutively active in the tumour cells, therefore constantly sending signals to stimulate proliferation, cell survival, invasiveness and angiogenesis.
