For every therapy, there will be several patients who respond to it ("responders") and other patients who do not ("non-responders"). Similarly, for every adverse reaction of a therapy, there will be some patients who are susceptible to it and others who are not. Unfortunately, the physician cannot recognize before the onset of the therapy whether the patient will be a responder or a non-responder, and whether the patient will be susceptible or not to a given adverse reaction. This fact has devastating consequences for the care of cancer patients:
- 75% of cancer patients who are treated with drugs ultimately do not respond to them, i.e. they are non-responders1,2. For every one of these patients, as well as for the physician who treats him/her, these therapies had no chance of success from the outset.
- After months of treatment, the cancer of a non-responder will have reached a more advanced stage, and precious time will have been lost for other treatments that would have worked in earlier stages.
- The severe adverse reactions that many non-responders to chemotherapy suffer from will lead to unnecessary impairment in the patients' quality of life.
- The enormous costs of the therapy for the numerous non-responders will ultimately be a meaningless burden on both the health care system and the co-insured patients.
From these facts, it is evident that there is an urgent need for drugs with higher specificity for cancer cells (targeted therapies), as well as a need for biomarkers of cancer and patient cells, which are able to predict therapy response and adverse drug reactions. This need will grow in the future, since the continuous increase of the world's population who are over 60 years old3 will lead to an inevitable rise of cancer incidence, and a subsequently increasing demand for cancer therapies.
- Marrer E & Dieterle F (2008) Biomarkers in Oncology drug development: rescuers or troublemakers? Expert Opini Drug Metab Toxicol 4:1391-1402.
- Spear BB, Heath-Chiozzi M & Huff J (2001) Clinical application of pharmacogenetics. Trends Mol Med 7:201‑204.
- The number of elderly people (60 years or older) is expected to more than double from 841 million people in 2013 to over 2 billion in 2050 worldwide (United Nations, Department of Economic and Social Affairs, Population Division (2013). World Population Ageing 2013. ST/ESA/SER.A/348. Seite xii).