What's a Clinical Trial and What Does It Involve?

The development of a clinical trial consists of 5 distinct phases. The aim is to ensure the efficacy and safety of a drug before launching it on the market. Find out more about this process in this article!
What's a Clinical Trial and What Does It Involve?

Last update: 13 April, 2021

.A clinical trial is an experimental evaluation of a drug in people. Its purpose is to evaluate the safety and efficacy of that drug.

When researchers compare an experimental drug with one that’s already gained approval and is used in routine practice, this shows whether the drug under investigation offers more benefits in comparison to the other.

Physicians offer clinical trials in practices to provide new experimental treatments to patients who have no alternative or to improve available treatments. This participation is completely voluntary and a patient can always leave the trial at any time they choose, without further explanation.

Also, the conducting of clinical trials is one of the essential phases in the marketing of a new drug. Without good results in these trials, no new drug can go on the market.

How is a clinical trial set up?

A woman and a man working in a laboratory.

The development of a clinical trial consists of five distinct phases. The first is the design of the study, which researchers and professionals in that therapeutic area carry out. During this phase, they design a protocol, which is a document that includes all the objectives and procedures they’ll follow. It’s like the trial’s instruction book.

The second phase is the approval of the trial. This approval has to be given by the relevant bodies, such as the FDA (Food and Drug Association) and the ethical committees. An international review board (IRB) will try to ensure safety and ethics for the patients.

The third phase is the recruitment of patients by the research teams of the hospitals participating in the clinical trial.

The fourth is the conduct of the trial itself. Clinical trials usually last several years during which the trial monitors make visits to the hospitals to check that everything is going according to protocol.

The last phase is the analysis of the results. Once the study is complete, a computer program called an electronic laboratory notebook processes all the data obtained. Researchers analyze this information to publish the results and make the scientific community aware of them.

What types of clinical trials are there?

There are different types of clinical trials depending on the objective the trial looks to achieve. In this regard, we can mention 4 main types of clinical trials:

  • In phase I trials, the aim is to evaluate the safety of a drug in humans. This is because they’re the first study of a molecule after animal experiments. They also evaluate the best means of administration and the most appropriate doses.
  • Phase II trials aim at evaluating the efficacy and safety of the drug in question.
  • Phase III trials take place to confirm the efficacy and safety of the study drug. This is done with a larger group of patients than in Phase II.
  • Phase II trials intend to evaluate the efficacy and safety of the drug to be marketed.
  • Phase IV trials take place when the drug is already on the market and aim at detecting and extracting more information from the drug, such as late adverse reactions.

The importance of clinical trials

A woman participating in a clinical trial.

Clinical trials are a great help in the development of new therapeutic options for many diseases, such as breast cancer.

They allow for the evaluation of all relevant aspects of the diseases in a highly regulated and strict manner. In some diseases, a trial can take years to discover a small piece of information. However, the sum of all the results is what allows us to advance in the clinic.

Indeed, trials don’t always demonstrate what’s researchers expect of them and don’t show a major benefit with the drug under study. Also, being a new drug, unexpected adverse reactions may appear. Although they’ll always be detected and dealt with very quickly.

However, they’re often a unique opportunity to receive an innovative treatment that won’t detract from health. In any case, it may not bring any benefit or help to overcome the disease more effectively.


Thanks to clinical research, progress can be made in the development of new treatments for diseases for which there’s currently no cure, such as metastatic breast cancer. It’s essential to contribute to this type of research to continue advancing and at least try to prolong the life expectancy of those with deadly diseases.

We encourage you to consult your doctor about the clinical trials available for your disease and ask them any questions you may have.

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