Resources for parents

Los ensayos clínicos son diseñados por profesionales médicos o de la salud. Para diseñar un ensayo clínico, es muy importante considerar iniciativas de investigación previas y ciertas cuestiones relacionadas con el tratamiento y los síntomas que precisan ser abordadas para que se de una mejora. Los aspectos éticos son también cruciales.

En el diseño de los ensayos clínicos hay diferentes participantes: médicos, enfermeras, pacientes, expertos en estadística y profesionales de apoyo, así como profesionales de la industria farmacéutica que colaboran para que el ensayo tenga el mejor diseño posible. El documento que recoge toda la información sobre el diseño del estudio se conoce como “protocolo”.

In this phase patients participation is higher than in phase I (between 100 and 300).

The goal of this phase is to study the effectiveness of a drug in relation to the possible secondary effects and the appropriate dose for the patient. In paediatric patients, this will be performed according to the different age groups.

Phase 4 is known as post-authorisation phase and it starts once the medicine is already in the market. Sanitary authorities require additional information from the pharmaceutical industry about the effects of the new drug in the “real world”. They also need to test the drug with more patients than those in Phase 3. 

At this stage, security and effectivity data are obtained with patient subgroups, comparing the effect of the drug in combination (or not) with other existing treatments.

Unless circumstances are excepcional, it is strictly forbidden to include a patient in a clinical trial without the previous signing of a document confirming his/her acceptance. This document is called informed consent and confirms that the participant or his/her legal representative have received the essential information relative to the study in order to decide to participate or not.

Informed consent is not a contract and it is possible to freely decide to abandon the clinical trial at any moment.

Bias are prejudices in favour of or against something, and it makes us wrongly conclude about the effects of a treatment. It is essential to detect any kind of bias in the biomedical research that may induce unsafe or ineficient studies, as well as the suspension of useful treatments.

Researchers try to avoid bias using aleatorization and anonymization (blind), thus obtaining objective assessments in the evaluation of the studies.

"Exclusion criteria" are those criteria established by the researchers determining that a patient can not participate in a clinical trial. An example would be those studies excluding pregnant women in order to prevent risk of fetus damage.

An exclusion criteria may also be taking any medication that may interact with the studied treatment.

A placebo is a substance that has no effect on the patient. It allows researchers to study the “placebo effect”. This is a psychological response in which the patient starts to feel better although he/she has not taken any treatment with an active ingredient in it. 

The comparison between the response of those patients that have taken the treatment and those who have taken the placebo helps researchers to analyze the benefits of the studied treatment.

It is possibe to have access to the information about the results of a trial once it has been completed. It should be considered that some studies involve thousands of people and that they could last for 5 years or more, exceeding the patient's participation period. 

Thus, there could be a difference of time between the moment when a patient leaves the study and the moment when the clinical trial ends.

Once the trial is finalized, the promoter (this can be a pharmaceutical company or a research centre) should make the results available to the participants. If someone is interested in this information, he could always ask the researcher or the patient's doctor about the conclusions of the trial.

Results should always include information about the benefits and risks of the studied treatments. This information will help the patient and other patients like him/her to make better decisions about healthcare.

Some researchers work with patient groups in order to ensure that the results of the trial reach those patients that have not participated in it. It is compulsory to publish the results of the trial although these have not been positive. This can be done via a medical congress, a scientific journal or the media.

With the purpose of ensuring that clinical trials meet standard ethical requirements, the majority of the studies meet those requirements established in the Declaration of Helsinki, which have additionaly been approved by the World Medical Organization. 

The most important requirement established in the Declaration of Helsinki is the obligation to obtain obtener informed consent before participating in the clinicla trial.