Future clinical trials will be much more targeted based on biomarkers and such drugs will only be tested on patient populations, said Dr P Umapathi, general manager, Analytical Research and Development, Micro Labs Ltd, Bangalore.
Biomarkers or indicators of normal biological processes play a vital part in identifying the patient populations such as those responding to drug therapies and those do not. Biomarkers become an inevitable part of the drug manufacturing companies to get their products approved as they are targeted to a specific patient population.
While delivering a special address in the national seminar on “a novel natural biomarker and its free radical role in chronic disorders” at Nanda College of Pharmacy in Erodu, he said biomarkers or biological markers help in preventing those patients who suffer severe side-effects of a drug, although it may derail the approval of the drug in specific sub-populations. There are some other factors about these indicators which have more importance in the field of clinical trials.
“Suppose a drug in a phase II trial was given to 100 patients with high cholesterol, 76 of the patients responded to the drug and their cholesterol level went down. The 24 patients were also treated with the same drug, but their cholesterol level did not change. These are what we call responders and non responders. We have to determine what are the genetic factors and what kind of biomarkers are associated with the patients that respond to the drug, and what are different from those patients who did not respond,” he said.
He said currently, clinical trials are designed to prove the efficacy of the drug in the entire disease population. For example, all people with high cholesterol, or all women with breast cancer. Pharma companies will use clinical trials to discover biomarkers in the disease population. They will design a clinical trial to treat the entire disease population.
“In future when you are with a doctor you give him a drop of blood, and once he has your entire genetic sequences, he can determine how best to treat you. That’s the goal of personalized medicine and that is how clinical trials will be designed in the future,” Dr Umapathi said.
According to him biomarkers are used for diagnosing disease, establishing disease risk, establishing drug response & toxicity, and predicting drug response & toxicity. They are key molecular or cellular events that link a specific environmental exposure to a health outcome. Besides, they play an important role in understanding the relationships between exposure to environmental chemicals, the development of chronic human diseases, and the identification of subgroups that are at increased risk for disease.
In medicine, a biomarker can be a substance that is introduced to an organism as a means to examine organ function or other aspects of health. For example, rubidium chloride is used as a radioactive isotope to evaluate perfusion of heart muscle.
It can also be a substance whose detection indicates a particular disease state, for example, the presence of an antibody may indicate an infection. A biomarker can also be used to indicate exposure to various environmental substances in epidemiology and toxicology. In these cases, the biomarker may be the external substance itself (e.g. asbestos particles), or a variant of the external substance processed by the body (a metabolite).
In cell biology, it is a molecule that allows for the detection and isolation of a particular cell type (for example, the protein Oct-4 is used as a biomarker to identify embryonic stem cells). In genetics, a biomarker (identified as genetic marker) is a DNA sequence that causes disease or is associated with susceptibility to disease.
Free radicals are unstable molecules that damage cells in the body and can cause chronic diseases such as cancer. Free radicals are the result of normal metabolic processes as well as exposure to toxins and pollutants, such as cigarette smoke. A free radical is “a very reactive atom or molecule typically possessing a single unpaired electron,” he said.