Clinical trial definition
Clinical Trial Definition

Clinical Trial Definition, and 4 Phases

Clinical Trial Definition, and Phases – Clinical Trials is one type of experimental, planned research that includes human subjects where researchers provide treatment or intervention on the subject of research.

Then the effects of the study were measured and analyzed. Basically Clinical Trials ensure the effectiveness, safety and picture of side effects that often arise in humans due to the administration of an intervention. Interventions can be in the form of medicines, vaccines, traditional remedies, medical devices and others named as test products.

The information generated from clinical trials is indispensable, considering that in medicine, clinicians need valid and credible information for the basis of objective selection of the given actions. While information coming from manufacturing is generally more unilateral, considering marketing and business aspects

Clinical Trial definition

What are clinical trials? Clinical Studies or Clinical Trials is any research on human subjects and it is intended to find or ascertain the clinical, pharmacological and/or other pharmacodynamic effects of the products studied and/or identify any unwanted reactions to the products studied, and/or to study the absorption, distribution, metabolism and excretion of the products studied for the purpose of ensuring their safety and/or effectiveness.

Clinical trials are a test of the efficacy of new drugs in humans, which was previously initiated by the animal or pre-clinical testing (Katzung, 1989).

Clinical trials: a method to see, evaluate whether an intervention is effective or not.

Clinical trial phases

Clinical trials are divided into several interconnected phases. Each phase or stage is intended to answer different questions. By knowing the phases in the clinical trials will be the knowledge for those of you who want to participate in clinical trials so that you know how far the drugs or therapies are being researched.

This clinical trial consists of phase I to phase IV trials.

Clinical trial phase 1

This phase is testing a new drug for the first time in humans. What is researched here is the safety of the drug, not its efficiency, so it is usually done on healthy volunteers.

The first goal of this phase is to determine the amount of a single acceptable dose, meaning that it does not cause serious side effects. The oral dose (by mouth, taken) given first in humans is usually 1/50 x the minimum dose that causes effects in animals. Depending on the data obtained in animals, the next dose is increased at least or with a multiple of two until obtained pharmacological effects or until undesirable effects arise. To look for toxic effects that may occur, hematological examination, the liver physiology, routine urine, and if necessary other more specific examinations.

In this phase also studied its pharmacodynamic and pharmacokinetic properties in humans. The results of this pharmacokinetic study were used to increase dose selection in subsequent studies. In addition, these results are compared with the test results in animals so that it is known in animal species where the drug undergoes pharmacokinetic processes such as in humans. If this species can be found, then long-term toxicity research is conducted on the animal.

This phase I clinical trial is conducted openly, meaning that without comparison and not disguised, on a small number of subjects with intense observation by experts in this field, and carried out in a place where the facilities are quite complete. The total number of subjects in this phase varies between 20-50 people.

Clinical trial phase 2

In the clinical trial phase 2, the researchers focused on seeing whether the treatment worked, finding the safest effective dose and determining what symptoms, tests, or results were the best measure of the efficacy of the treatment.

Determining the best success step is important for designing the final stage of testing.

All clinical trial phase 2 was conducted randomized and placebo controlled.

This phase of research can take months to years, and only about a third of the drugs in phase 2 clinical trials pass through to the next phase.

In phase 2 clinical trials, researchers delivered the drug to hundreds of subjects and monitored safety through routine testing. To measure effectiveness, researchers looked at clinical responses such as duration of disease, severity of the disease or survival rate.

Direct measurements of a disease such as the number of viruses in a person’s body are also monitored, as well as biomarker signals in the body that researchers know are altered by targeted diseases.

At this point, the researchers will use all the information they obtained to design a phase 3 clinical trial. They decide what action to use, the dosage to test and its type, or the cohort (risk factors and effects within a given period) of the person being tested.

If there is evidence in phase 1 or phase 2 that the drug or vaccine is unsafe or ineffective, then the team will discontinue the trial.

Clinical Trial phase 3

In Clinical Trial Phase III is conducting drug testing with the following conditions:

  • In sick humans, there are control groups and comparison groups
  • Wider coverage both in terms of patient numbers and diversity (e.g. intra-racial
  • Once proven effective and safe the drug is ready to be marketed

Phase III clinical trials are conducted to ensure that a new drug is completely efficacious (similar to research in phase II) and to determine its standing compared to standard medicines.

This research will at the same time answer questions about

  • Its effects when used widely and administered by doctors who are ‘less expert’;
  • Other side effects that have not been seen in phase II;
  • And the impact of its use on patients who are not strictly selected.

Phase III clinical trials are conducted on a large number of patients who are not strictly selected and carried out by people who are not very experts, so it resembles the actual situation in daily use in society.

In clinical trial phase III, this is usually a comparison done with placebo, the same drug, but different doses, standard drugs with equivalent dose, or other drugs which indications are the same as the dose that is exclusive. The tests were conducted randomly and double-blind.

If the results of phase III clinical trials show that the new drug is quite safe and effective, then the drug can be allowed to be marketed. The number of patients included in phase III is at least 500 people

Clinical trial phase 4.

After the drug was marketed still conducted post marketing surveillance studies observed in patients with various conditions, various ages and races. This study was conducted in the long term to look at the therapist and long-term experience in using the drug.

Once the results of the IV study are evaluated it still allows the drug to be withdrawn from the trade if it is harmful. For example cerivastatin (an anti hypercholesterolemia that can damage the kidneys), entero-vioform (chloroquine, an anti-amoebic dysentery that in Japanese people can cause paralysis in the eye muscles), phenylpropanolamine / PPA that is often present in flu drugs should be lowered in dose from 25 mg to no more than 15 mg because it can increase blood pressure and heart contractions, troglitazone (antidiabetic that can damage the liver), and Viox (rofecoxib) which can damage the heart.


Last Updated on April 29, 2021 Reviewed by Market Health Beauty Team


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