This post is the first one on Clinical Trials. In this post, we define and describe clinical trials and different terms which we come across any clinical trial paper. Attached also is an example for better understanding the terms given here.

Clinical trials can be defined as an *interventional research studies that explore the safety and effectiveness of a medical treatment or device in humans. In other words, it can be described as a study in which participants are assigned to receive one or more interventions or no intervention to evaluate the effects of the interventions on biomedical health related outcomes. The intervention can be diagnostic, therapeutic, medical treatment, surgical operations etc.

(*The term intervention means to interfere in the course of the research study. That is, it is not a study where the researcher only observes and records the final undisturbed outcome, but here the researcher makes changes in the course of the study and tries to change the outcome.

For eg: observational study would be to find out how many persons smoke in the group of 500 individuals. Here the researcher will only count/find the number of smokers and not really ask them to stop.

In an interventional study, the researcher can make change in the course of smoking. Therefore, an interventional study would be one wherein the group of individuals are given a lecture/ medication to quit smoke and then find the total number of smokers and analyze the effect of the intervention (lecture/ medication). Hence intervention study involves an intervention to change the otherwise natural outcome and analysing the effect of intervention itself.)

Clinical trials usually compare the effectiveness and safety of these treatments or combinations thereof. Mostly the intention is to improve the condition of an individual/s. Clinical trials (in humans) are carried out in human after a number of preclinical studies (which include in silico, in vitro and in animal studies).

These trials require interdisciplinary personnel including basic scientists, clinical pharmacologists, clinician specialists, statisticians and others. There is a great need for stringent guidelines, good design and execution as testing on humans are involved. Less than 30% of drugs tested in clinical trials can reach the marketplace.

To really understand Clinical Trials, we need to know some terms used often in these studies. Different terminologies in the clinical trial include:

  1. Population:

It is the group of individuals from which a subset is going to chosen to do intervention on and the one to which the findings should be extrapolated. The first step is to specify the target population.

e.g. Mumbai, a hospital, a slum, a school, India, women

  1. Subjects:

A group (subset) of Individuals or participants selected for study from the target population. It is a representation of the target population, which actually participate in the trial. The results obtained from the experiments on these individuals are extrapolated to the entire target population.

All the subjects chosen for the study should have a baseline characteristic, whose progression is to be investigated. For example, in case of cease-smoking treatment, all the subjects should be smokers.

All the subjects with the baseline characteristics are then divided into two groups: test and control. The test group is the one which is given the test treatment under investigation, and the control group could either have no treatment, the standard available treatment or the placebo.

Other than baseline characteristic, subjects should have specific set of characteristics to be included or excluded from the study, this is put up as inclusion and exclusion criteria. Inclusion criteria specifies the type of patients who are eligible for the examination. Exclusion criteria specifies the factors which should not be present in the patients, hence they are excluded. These criteria are listed for safety concerns of the patients and to avoid any risks to them. These criteria also helps to seek reliable and balanced results, i.e. too high or too low readings may change the results drastically, so a range is set for including the subject.

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Example of clinical trial.

Please read and understand the above example: In the above example:

Population: Newborns with non-hemoitic hyperbilirubinemia (jaundice).

Subjects: 90 neonates with non-hemolitic jaundice.

Baseline characteristics: newborns should have non-hemolitic jaundice.

Also see Inclusion criteria and exclusion criteria.

(Just for info: Here’s a site Pancreatic Cancer Action Network which talks about clinical trials in Pancreatic Cancer)

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Read other posts by The Biotech Notes:

Clinical Trials (P-2): Randomization.

Clinical Trials (P-3): Placebo effect and Blinding

Clinical Trials (P-4): Experimental Designs

Clinical Trials (P-5): Phases of Clinical Trials.

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