Today biomarker testing is commonly employed in clinical trials. Test biomarkers are considered primary endpoints in clinical testing. They are well characterized and have shown a correlation in predicting relevant study outcomes. Hence, their increasing use is entirely appropriate and justified. However, researchers must not only focus on biomarker validation, but also evaluate and reevaluate its validity in clinical biomarker testing. The current article is a quick guide to clinical biomarkers. It also highlights bioanalytical solutions provided by biomarker assay services and biomarker testing services.
Biomarkers vs. Clinical Endpoints
Clinical endpoints are measurable elements that reflect how an individual function, feels or survives. By definition, biomarkers are objective and quantifiable features of biological or pathological processes. It is not necessary that biomarkers may correlate with a patient’s health and well-being, or changes in their levels may go undetected without affecting the health. In contrast, clinical endpoints are entirely different from biomarkers. They represent a patient’s health and well-being..
Evidently, clinical endpoints are the primary and most relevant endpoints in all biomedical research. The ultimate aim of biomedical studies is to improve the health of the patient population and not just change any quantifiable patient’s characteristics. Similarly, patients consider therapeutic interventions for their diseases and medical conditions and not for numerical assessments that may not necessarily correlate with their ailments.
For example, survival is the primary and most crucial endpoint for most HIV studies. However, other well-characterized variables, such as myocardial infarction and stroke, have also been considered under certain circumstances. These variables offer data with the potential to determine the efficacy and safety of clinical trials. Hence, not all clinical endpoints are equal, though they may help generate clinical data, especially in complex scenarios.
Biomarkers as Surrogate Endpoints
Surrogate endpoints are biomarkers used in clinical trials. These biomarkers can act as surrogates for clinically meaningful endpoints. However, all biomarkers are not surrogate endpoints. These biomarkers are well characterized and evaluated based on solid scientific evidence. Surrogate biomarkers must accurately and consistently predict either a harmful or beneficial outcome. Although surrogate endpoints can stand in for a clinical endpoint, they cannot be a replacement.
Even statistically valid surrogates may not necessarily be a part of the pathological pathway. In some circumstances, the biomarker may measure a product or process of a distinct pathway. However, assuming correlation for causation in all cases can be risky. A surrogate biomarker may correlate with a specific scenario for many reasons. For instance, the biomarker might indirectly indicate the disease pathway without any key role in the pathophysiology.
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However, there are many advantages to using surrogate biomarkers in clinical trials. The primary endpoints of survival in certain diseases, such as cardiovascular events, are so infrequent that they are impractical in clinical trials. Besides, the possibility of the endpoint may happen only after a very long time. Biomarkers as surrogate endpoints can provide researchers with interim safety and efficacy data. Moreover, surrogate biomarkers can help stop potentially harmful interventions early to reduce risks to the study subjects. Such interventions can help researchers better design and execute clinical trials.