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Fundamentals of Clinical Trials and Phases of Clinical Trials

A Blueprint for Reliable Research

Fundamentals of Clinical Trials :

Most errors in clinical trials are a result of poor planning. Careful planning with proper foresight is crucial. The objective of clinical trials is to establish the effect of the intervention. The key features of clinical trials to meet these objectives are randomization, blinding, prospective evaluation, and a control group. Many issues have to consider when designing clinical trials. Fundamental issues include:

Fig 1: Clinical Trial ICH GCP

• Clearly defining the research question

• Minimizing variation

• Randomization

• Stratification

• Selection of the population for trial

• placebo

• The selection of endpoint

• Sample size

• Planning of internment analysis

Phases of Clinical Trials

Fig 2: Fundamentals of clinical trials 

The design of every clinical trial starts with basic research questions. These research questions must be clear enough to help a vague concept to a particular hypothesis that we can test. There are two strategies to design research questions. One strategy is hypothesis testing, where research presents a thanks hypothesis. Then it outlines questions to disapprove it. There is an alternative hypothesis having questions that support it. The second strategy is estimation. For example, a trial must be planned to estimate the difference between two therapies with appropriate precision. (Scott R. Evans, 2011)

What is a randomized clinical trial?

Randomization is a powerful tool that helps control for bias in clinical trials. In randomized clinical trials, subjects were assigned randomly to one or more than two therapies and then treated in an identic identically potential visible. Randomized control trials are the most critical way of determining whether a cause-effect relationship exists between treatment and outcome and for accessing the cost-effectiveness of treatment.

Clinical trials are divided into phases based on the object of the trial. There are four phases of clinical trials that are as follows.

1-Phase 1 clinical trial

2- Phase 2 clinical trial

3- Phase 3 clinical trial

4- Phase 4 clinical trial

What is a phase 1 clinical trial?

Phase 1 trial, known as drug escalation in human pharmacology, is the first instance when new investigational agents are studied on humans. These experiments are usually performed in a small number of healthy as well as diseased individuals. Phase 1 studies are to find how many doses of a drug can be administered safely trial tout causing any toxicity in individuals.

What is a phase 2 clinical trial?

Phase 2 trial, known as therapeutic exploratory, is usually larger than phase 1 trial and is conducted in small numbers to a volunteer who has the disease of interest. Phase 2 trial determines the safety, pharmacokinetics, and pharmacodynamics of the drug. It is also essential to get answers to questions that are essential for planning phase 3 trials.

What is a phase 3 clinical trial? 

A phase 3 clinical trial, known as therapeutic confirmatory, is conduct over a more diverse group of individuals to demonstrate and check the efficacy of drugs. It is also necessary to estimate the incidence of common side effects.

What is a phase 4 clinical trial? 

 Phase 4 trials know as therapeutic use, are observational studies performed on FDA-approved drugs. Identify less common adverse effects and check the efficacy and effectiveness of the drug.

Fig 3:  Phases of Clinical Trials   

References:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3083073/ - Fundamentals of clinical trial design
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3272827/ - Key Concepts of Clinical Trials: A Narrative Review
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5989153/ - Clinical trial design and dissemination: comprehensive analysis of clinicaltrials.gov and PubMed data since 2005
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1884542/ - What is a clinical trial?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6662388/ - Regulatory Affairs 101: Introduction to Investigational New Drug Applications and Clinical Trial Applications

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