CLINICAL TRIALS IN HUMANS

A clinical trial consist of research using human volunteers (also called participants) that is intended to add to medical knowledge.

There are two types of clinical trial:

1. Interventional trial
2. Observational trials

In a clinical trial, participants receive specific medicine or treatment or intervention according to the research plan or protocol created by the physician or investigators. These treatments may be medical products, such as drugs or devices; procedures; or changes to participants' behavior, e.g, diet.

Clinical trials compares a new medical method to an already available medical method, to a placebo (no medical substance/no active ingredients), or to no intervention.

Some clinical trials compare interventions that are already available to each other.

When a new product or method is being studied, it is not usually known whether the new product or method will be safe, unsafe, or no different than available alternatives. The physician tries to decide the safety and effectiveness (efficacy) of the intervention by evaluating certain outcomes in the participants. Such as E.g, the physician may give a drug or treatment to participants who have high blood glucose to see whether their blood glucose decreases.

Clinical trials used in drug development are sometimes described by stage or phase. These phases are demarcated by the Food and Drug Administration (FDA).

Some individuals who are not eligible to participate in a clinical trial may be able to get trial drugs or devices outside of a clinical trial through an Expanded Access Program.

Stages or Phases in Clinical Trials:

The FDA has provided five phases with their descriptions below:

1. Phase 0: This phase also known as Exploratory study.This phase involves very limited human contact to the drug, with no therapeutic or diagnostic goals. this phase is explored in two different trials (Screening trials and Microdose trials)
2. Phase 1: Studies that are usually conducted in healthy volunteers and that give emphasis to safety. In this phase the physician tries to find the dose of the drug. The goal of this phase is to find out what the drug's most frequent and serious adverse events are and, often, how the drug is metabolized and excreted.
3. Phase 2: This phase of trial helps to know whether the drug works in people who have a certain disease or condition. Safety of the patients continues to be evaluated, and short-term adverse events are monitored.
4. Phase 3: This phase of the trial that emphasize on more information about safety and effectiveness by studying different people and different dosages and by using the drug in combination with other drugs.
5. Phase 4: Pharmaceutical companies’ conduct these phase of trial after the FDA has approved a drug for marketing. The objective of these studies to gather additional information about a drug's safety, effectiveness, or best use.

Observational Trials:

In an observational trial, the physicians or investigators evaluate health outcomes in groups of participants according to a research plan or protocol. Participants may receive medical products such as drugs or devices or procedures as part of their regular medical care, but participants are not allotted to specific interventions as per assignment in a clinical trial. For instance, physicians may observe a group of older adults to learn more about the effects of different lifestyles on cancer health.

etabolized and excreted.