Medicines save and transform people's lives, but the process of developing and approving a medicine is long, rigorous and complex, taking several years to complete.
Initially, medicines are studied in a laboratory during the so-called pre-clinical phase. If the initial results are promising, the experimental medicines undergo rigorous testing to determine whether they work effectively, are stable, and produce reproducible and reliable results. These tests can be done using computer simulations, cell culture models, or, only when strictly necessary, on animals. If the medicines pass this stage, they are formulated into safe and robust medicines that can be used in clinical trials, so that they can be carefully tested in people.
Clinical trials aim to see if a medicine is safe and effective in treating or preventing the disease for which it has been developed; if it achieves better results than existing therapies; and if it improves patients' quality of life The approval of a medicine by regulatory authorities and its entry into the market depends on the submission of a scientific dossier, of which the results of clinical trials are a fundamental component.
Phases of clinical trials
Clinical trials are carefully designed, reviewed, and programmed, and must be approved by regulatory authorities and ethics committees before they are initiated. People of all ages may participate, according to pre-specified eligibility criteria.
Clinical trials are divided into four phases:
20-100 healthy volunteers
The purpose of this phase is to evaluate the medicine's safety and discover any adverse effects. The aim is to understand how the medicine works in the human body, and to determine what is an appropriate dose to use in the phases that follow. This phase is short, and volunteers are monitored very closely at the research centre where the study is being conducted.
100-300 patients
Participants in this phase are people with the disease for which the treatment has been developed. Besides evaluating the safety and efficacy of the drug in the short term, usually against a placebo (a drug with no active ingredient), this type of study seeks to test the drug in different patient groups and at different doses.
Hundreds or thousands of patients
With many more participants, Phase III clinical trials aim to determine whether the medication can be considered safe and effective in the medium to long term. To do so, the medicine is compared with a placebo and/or with other medicines. Phase III trials are conducted in larger populations and in different countries, and are usually the step before a new medicine is approved.
Several thousand patients
This type of study is conducted after the medicine has been approved by the respective authorities and aims to analyse its efficacy and safety in a very large and varied set of patients in the context of everyday clinical practice.
The results of clinical trials are submitted to the authorities for approval and marketing authorisation before they are made available to patients. This approval confirms the quality, efficacy and safety of the new medicine. Although no medicine is risk-free, a marketing authorisation indicates that everything has been checked properly and that the benefits outweigh the risks.