What is the story behind the concept of personalized medicine?

Over time, the question that every doctor asks him/herself, that is: “What medicine can I use to treat the diagnosed illness of my patient X as effectively and with as few side effects as possible?“ resulted in the realization that the patient’s individual characteristics had indeed a large influence of the success of the therapy.

Why, for example, do several patients with the same diagnosis respond to a treatment with the same drug so differently, both in terms of efficacy as well as tolerance?

In addition to the "classical" parameters that affect the efficacy and side effects of drug therapy (such as age, gender, lifestyle, etc. ...), a lot of information about the human genome has been collected over the past years, and it became more and more clear how helpful it is to have certain genetic information together with the diagnosis in order to better assess the prospects for therapeutic success.

In recent months, the topic was often enough discussed in the media on the example of breast cancer when it became clear that the presence or absence of certain genes makes it more likely to get the disease, not because these genes cause cancer directly, but because certain cancer-inhibiting mechanisms no longer work.

The example of oncology

In Germany, cancer is the second most common cause of death after cardiovascular disease. On average, the 5-year survival rate is about 55%.This is why oncology is one of the most important fields for research and development in the pharmaceutical industry.

But how does a tumor actually develop?

In a healthy organism, there is a balance between the proliferation and death of cells in every organ. If a cell has "forgotten" the program for its death, this balance - also called homeostasis –is disturbed: the cell doesn’t stop to multiply, resulting in more and more cells. If the encoded control mechanisms of the body don’t work (anymore), the cancer cells grow unchecked.

There are different reasons for this, which are very complex and are still being researched, but often they can be found in a mutation within the genome. Every person has his own unique gene combination that is stored in each cell and is present there in the form of a DNA strand, which would reach a length of 1.80 m if it were "rolled" out! Each cell therefore stores the entire gene combination, but in case of a mutation - whether congenital or not - the genetic code is changed and important biological mechanisms may be disrupted accordingly.

In part, the cancer cells can be destroyed by the body’s own immune system, and this process –from the detection to the destruction of cancer cells - is also extremely complex and requires the intervention of many cell types and enzymes whose production is genetically programmed.

The human genome, with approximately 25,000 genes, has been officially deemed completely decoded since April 2003. It is estimated that about 5,000 of these are responsible for the safe preservation of the genetic code from one cell generation to the next. Other genes, for example, are responsible for the production of certain proteins, like enzymes, which are crucial in all biological processes such as the body’s immune response or response to a drug therapy.

Although the role of many genes is currently being researched and still unclear, pharmacogenomics holds the promise of exciting opportunities for the pharmaceutical industry.

The approach of personalized medicine implies that the therapy will be dependent on biological test results of the patient, such as genotypic tests or other diagnostic procedures.

If the doctor has used an approved drug for a patient with a specific diagnosis (e.g. prostate cancer), and he has regularly monitored its efficacy and tolerability to determine the further course of action, the new drugs will change his approach so that in addition to the diagnosis (e.g. prostate carcinoma with some extremely specific information), individual characteristics of the patient (e.g. biomarkers such as genotype information) will also be taken into account, allowing him/her to start the best possible treatment for the patient much sooner and more accurately.

In future, patients will receive an individual therapy that is as "tailor-made" as possible. The vision is: "The right drug for the right patient at the right dose" - the greatest hope of all patients!

Using this principle, it will be possible to spare the patient unnecessary therapy approaches, because the diagnostic results allow you to better predict the probability of treatment success. This not only means great savings of money, but also of time, which in many therapeutic areas such as oncology is a crucial factor for patient survival and/or recovery.

In addition to oncology, there are other applications such as in the field of autoimmune diseases where this principle also seems very promising.

The concept of personalized medicine can also be complemented by other approaches. One expects that not only genotyping methods, but also other ideas such as imaging techniques etc. will be developed for diagnostic procedures.

It is also conceivable that drugs already approved for adults could also become suitable for children up to infants, because the dosage –depending on the activity of certain enzymes –can be adapted. Medical technology also wants to offer patients new products that are "tailor-made", such as heart valves or prostheses that are covered with the patient's own cells, so that these are recognized as endogenous and are not rejected, etc.

The concept of personalized medicine therefore holds a wealth of new ideas for medical progress!

 

Autor: Cécilia Mesa, 21.03.2014

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