According to the FDA (Food and Drug Administration) and the NIH (National Institutes of Health), a biomarker or biological marker is “a defined characteristic is measured as an indicator of normal biological processes, pathogenic processes or reactions to exposure or intervention, including therapeutic interventions”.https://www.fda.gov/files/BIOMARKER-TERMINOLOGY–SPEAKING-THE-SAME-LANGUAGE.pdf
Different types of biomarkers
A biological marker can be any biological indicator that can be measured. Biomarkers can be molecular or cellular. They will be measured from a tissue or liquid biopsy such as saliva, blood, etc.
Clinical or medical imaging will also be able to measure other biomarkers (morphological, physiological…). Biomarkers used in imaging are also an important avenue for development. Imaging biomarkers are defined as anatomical, physiological or molecular parameters that can be detected with one or more imaging modalities: scanner, magnetic resonance imaging (MRI), ultrasound… They will make it possible to detect lesions but also to monitor the evolution of a pathology to detect or monitor the patient’s response following treatment.
Biomarkers can be quantitative or qualitative. Quantitatives biomarkers are involved in the detection of the pathogenic process with a threshold effect, while qualitativescould be part of the detection of pathogenic process in the context of an analysis or not.
In the medical field, the biomarker can be used to detect a disease in a population, make a diagnosis, provide a response to medical treatment, prevent relapse after treatment.
So today we distinguish two types of biomarkers that have different rules of development and acceptance:
- The biomarker used independently of a specific drug such as for diagnosis or clinical follow-up,
- The biomarker “companion” to a drug. In this category, two types of biomarkers are present:
- Biomarkers used only once before a drug is prescribed to select patients who may or may not benefit from treatment
- Biomarkers used in combination with the drug to assess its efficacy or toxicity at an early stage.
The challenges of biomarkers in cancer treatment
In cancer treatment, clinical practices that have always been carried out are now being replaced by new approaches. Previously, cancer patients were treated with drugs of low toxicity or high tolerance, regardless of their efficacy in a given patient, if the benefits of this drug are proven under experimental and clinical conditions.
However, recent advances in basic and clinical research have made it possible to develop personalized treatment strategies.
These new approaches aim to determine the individual benefits of therapies for patients, minimize the risk of toxicity and reduce the cost of treatment.
The development of dedicated diagnostics to guide the use of targeted therapies in oncology offers the prospect of better therapeutic outcomes and reduced exposure to toxicity for many patients. The recent emergence of biomarker selection and monitoring strategies for treatment selection and monitoring demonstrates the promise of biomarkers in the field of cancer.
Currently, there are 32 valid biomarkers listed by the FDA in a different range of therapeutic areas, with cancer being the most important one.
For biomarkers in cancer application, the challenges as well as the benefits seem enormous. To make the necessary progress in cancer treatment, a patient’s disease must be monitored effectively and efficiently.
Biomarkers in the daily life of doctor
Most physicians are familiar with the role of diagnostic tests in clarifying and supporting clinical decision-making. In recent years, the diagnostic process has been increasingly influenced by the need to screen patients according to drug names or classifications.
This evolution is explained by a number of factors, by which:
- The advancement of technology,
- A better understanding of the disease process,
- A better appreciation of the uniqueness of an individual’s phenotype at the molecular level.
This decision is also motivated by societal factors, the most important of which is the need to limit targeted therapies to those patients most likely to benefit from them. With the advent of precision medicine, the so-called “one size fits all” medical approach is part of history.
The fundamental promise of personalized medicine is that the diagnosis and treatment of diseases will become ever faster, cheaper, more accurate and more effective.