Biomarkers as key players in drug development
A biological marker or biomarker is a molecule or parameter that can measure a state of health or disease. It can be used to detect a disease, a physiological change, a response to a treatment or a mental disorder. For example, glucose levels are used as a biomarker to monitor diabetes, and brain MRIs can provide information about the progression of multiple sclerosis.
Biomarkers are used in many scientific fields and also in different phases of drug development. Since the precision of biomarkers may vary, not all of them are suitable for drug development, that is, to measure their efficacy and effectiveness.
Biomarkers can be used to measure:
- Normal biological processes, such as heart rate, blood pressure, temperature, etc.
- Pathological processes (disease). For example, to find out the stage of the disease.
- Response to a treatment or medication. For example, to know if an immunotherapy treatment is working we will measure certain molecules and we will known if we are on the right track.
Some examples of biomarkers are:
- Biological molecules, such as enzymes (biological substances that cause changes in the body and accelerate or catalyse chemical reactions), which can be found in blood or tissue samples (for example, in the case of cancer).
- Genetic modifications: DNA methylation, that is, specific chemical changes experienced by some genes or DNA sequences and that determine whether they are expressed or not in the form of proteins; also, the level of expression of certain genes, etc.
- Medical imaging: magnetic resonances (MRI)) or radiographies. Quantitative parameters that are extracted from radiological images after applying computational models.
Objectives of the use of biomarkers
The two main objectives of the use of biomarkers in the field of drug development are the following:
1. Improvement of drug development processes
The purpose of clinical trials is to measure how patients respond to a treatment. If it is not possible to measure this response directly, biomarkers may be an alternative method of measuring an outcome (using surrogate endpoints).
A clear example of the use of a biomarker as a surrogate endpoint is the development of antiretrovirals for the treatment of HIV infection. Previously, studies were based on objective endpoints, such as progression of HIV infection or patient survival. Currently, changes in certain cells (eg, CD4 T helper cell concentration) and changes in plasma virus RNA concentration can be used as surrogate endpoints.
2. Personalised medicine
Research in the field of biomarkers is helping to improve prediction of the risk of developing a disease, the evolution of the disease and response to drugs. This will allow to make safer and more effective decisions when it comes to treatment.
For example:
- Blood sugar level can be used to monitor response to diabetes treatment.
- Magnetic resonance imaging (MRI) of a patient's brain can be used to monitor the progress of multiple sclerosis.
In addition, through scientific disciplines like genomics (analysis of changes in the genes), proteomics (analysis of changes in protein concentration) and metabolomics (analysis of differences in biological molecules), more and more biomarkers are being discovered, which will be extremely useful for the design of new personalised treatments.
