The importance of genes for the success of a therapy
A patient's genetic dispositions play a special role in the context of biomarkers. Individual differences in a person's genetic makeup can affect how well a drug works or is tolerated.
The science that studies the relationship between a person's genetic dispositions and the body's individual response to a drug is called pharmacogenetics. This branch of science is becoming increasingly important in pharmaceutical research and development. At Bayer, too, pharmacogenetic findings have an impact at various stages of the development process.
DNA variations influence a drug’s effect
Some patients give DNA samples in the course of clinical trials (on the basis of individual agreements) to enable researchers to determine such differences. Polymerase chain reaction (PCR), a process that was honored with the Nobel Prize in Chemistry in 1993, is used to reproduce (by adding the enzyme DNA polymerase) a DNA segment that is known to be responsible for the production of the relevant receptors. The segment is then examined in robot-based serial tests in a process similar to high-throughput screening. This enables the researchers to determine whether certain variations in this gene segment correlate with a stronger or weaker effect of the drug, or perhaps with its tolerability.
If the DNA building block that is responsible for the drug's effect is not known, the scientists at Bayer may track it down via the technology of sequencing, in which the order of the building blocks on the patient gene relevant to the disease is compared with the normal sequence in the human genome. Any deviating building blocks are then further examined by PCR.
The results of these tests (after being pseudonymized) contribute to the study data. If it turns out that certain elements of the genetic makeup are preventing the drug from having an effect, physicians can conduct corresponding tests prior to treatment to ensure that only patients with prospects of a positive drug effect are treated and the others are spared a potentially unsuccessful treatment. It is also possible to measure correlations between genetic patterns and the rate at which the drug is broken down, thus providing valuable insights on the safety and proper dosage of the drug.
Strict data protection
Researchers hope that pharmacogenetics will lead to therapies in which the active ingredient and dosage are tailored to a patient's individual genetic dispositions (see personalized medicine).
Pharmacogenetic research also raises ethical, legal and social issues, however. Principles such as compliance with strict data-protection regulations and the maintenance of confidentiality in dealing with the collected genetic information are fundamental to all Bayer's scientific work with genetic material.