A therapy is not equally effective in all patients with the same disease, and in some it can in fact cause severe adverse effects. Personalised medicine is an overarching term used to describe the strategy of developing medicinal products that are better adapted to the individual patient. It also enables more precise diagnoses to be made.
Biomarkers as the starting point
In personalised medicine, the aim is to use knowledge about the patient’s individual biological or genetic profile in addition to the clinical picture to assess before treatment starts whether the patient is likely to respond to a specific therapy. Specific circumstances in which, for example, the patient’s genetic profile plays a role can be identified using modern biomarkers. These are measurable parameters within biological processes that have a prognostic or diagnostic value.
In this way, personalised medicine aims to identify different causes and patterns of disease and to develop corresponding treatments. One example is breast cancer. Breast cancer cells are abnormal cells in the body whose growth mutates and spirals out of control as a result of certain genetic changes. They differ in genetic terms, and this influences the success of therapy. Around one quarter of all breast cancer patients over-express the protein HER2 in their cancer cells. Compared with an HER2-negative tumour, an HER2-positive tumour takes a more aggressive course and the tumour recurs more rapidly, which is why a personalised approach to therapy is so important for HER2-positive patients.
This approach has enabled a specific antibody to HER2 to be developed that stops further growth of the tumour and activates the body’s immune defences. This therapy is beneficial solely for patients with over-expression of HER2 receptors, meaning that the HER2 status of women with breast cancer needs to be determined as early as possible.
Higher rate of therapeutic success, better tolerability
This example shows that personalised medicine increases the success of a therapy while at the same time reducing the cost to the health system and sparing patients unnecessary treatments.
Yet personalised medicine focuses not only on efficacy but also on improving the tolerability of therapy. Whether a patient tolerates an active substance or it causes more adverse effects than usual can also be determined by that patient’s DNA. In cases of AIDS, for example, a specific mutation of the HLA-B5701 gene is linked to hypersensitivity to a certain medicinal product. Nowadays, therefore, a test is first carried out to see whether a patient carries the mutated gene or not. Fewer adverse effects during therapy means a better quality of life for patients and this in turn encourages them and their doctors to have greater confidence in that therapy.
What does the future hold for personalised medicine?
Personalised medicine is no longer a vision of the future. It has already arrived in the Swiss healthcare system and many authorised active substances are available for specific patient groups. A companion diagnostic test is required, or at least recommended, for most of these active substances. The development of new gene and cell therapies has also been boosted by the discovery of the CRISPR/Cas process.
In spite of all the progress that has been made, it is still an enormous challenge to implement personalised medicine in the real-life setting of doctors’ practices and hospitals. The results of a survey carried out by the Swiss medical journal Schweizerische Ärztezeitung show that improved postgraduate medical training plays an important role. In the survey, 35% of respondents said they did not feel well (or at all) informed about personalised medicine, 48% felt moderately well informed and 17% felt (very) well informed.