What is a clinical trial?


Clinical research helps improve care and treatment of patients with cancer. A clinical trial is the final step before the launch of a medication or technique or the implementation of a new therapeutic strategy.

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It is important to distinguish basic research – which takes place in laboratories – from clinical research, which is conducted with the patient and for the benefit of the patient. There are also different types of clinical study:

  • Observational or “non-interventionist” studies, where data are recorded during standard explorations and treatments.
  • Interventionist clinical studies: these require intervention in addition to that which is normally expected in standard patient care. They thus require the patient’s consent. Some of these studies test new treatments, new therapeutic combinations or other procedures (such as a new exam, protocol-based psychological monitoring, etc.). Interventionist clinical studies are therefore not all intended to develop new treatments. They may also serve to help understand the mechanisms of cancer development, to better understand the tumor’s interactions with its environment, or to make technological progress in imaging: all of these fields of clinical research help develop more effective tools for diagnosis, prognosis, treatments and prediction of the response to treatments. Unlike observational studies, these interventionist studies with a cognitive purpose require an intervention (blood test, imaging exam, etc.).

Concerning interventionist studies assessing new therapeutic approaches, they can only begin when this new therapeutic strategy has completed all the laboratory validation phases and then the preclinical exploration phases. The goal is to assess the safety and effectiveness of the molecule or technique in order to eventually offer patients more effective treatments with fewer side effects.


The various steps in a clinical trial

By definition, interventionist clinical studies include patient volunteers who meet very specific criteria. The protocol is explained to the patient, who can choose whether or not to participate. When it is a trial for a new treatment, the development takes place in several steps:

  • A phase-I study, including a few patients and aiming to assess the molecule’s tolerance and determine the optimum dose.
  • A phase-II study, to assess anti-tumor activity.
  • The phase-III studies, which involve the participation of a number of patients. Such studies compare a new treatment with the reference treatment. These studies are sometimes double-blind, which means that neither the patient nor the physician knows who is receiving the new treatment and who is receiving the usual one.

Only after these three phases can the treatment obtain market authorization.

Once the treatment is on the market, it enters what is known as phase IV. This is a long-term phase which helps to further knowledge of the medication in actual conditions of use, assess its tolerance on a larger number of people and detect any unwanted side effects over a longer observation period.

Regardless of their purpose, all of these phases take place within a strict framework. Beyond regulatory constraints, at Institut Curie the search never ends as research authorities and participants are constantly evaluating the methods and protocols, as well as the scope and challenges, of the trials.