Epidermolysis bullosa

The clinical trials are the centre of all medical advances. On them it is studied if a potential new drug or therapy is safe and effective on people. They are divided in 4 phases, but: what is done in each phase? In this section we will explain it a bit more.

• Phase I: On phase I of a clinical trial, it is tested if the new drug or therapy is safe. It will be the first time it is administered to people and normally a reduced group of people take part in it. These studies serve as a guide to know the intake form (oral, intravenous, etc.) and administration schedule (daily, 1 every 15 days, etc.) To do that, the secondary effects, the tolerance and the best administration way will be evaluated, and the safe doses will be determined. If severe secondary effects appear the study will be stopped. If everything goes alright and the drugs proves to be safe, we will move to phase II.
• Phase II: In this phase, it is analysed if the drug works, if it is effective. To prove that a new treatment works, the clinical research staff must clearly know what tests or measurements will have to be taken to obtain the necessary data. No new tests may be added during the trial. Only what is stipulated in the initially approved protocol can be done and for this reason its correct design is so important. Phase II usually lasts longer than phase I studies. Sometimes there are trials that do phase I and II at the same time.
• Phase III:If phase II is passed, the next phase, phase III, will be started. In this phase, the safety and efficacy of the drug are verified in a larger number of participants. A dose and route of administration are established. If there are already other treatments available on the market, they will be compared to see if the new treatment is better. If the results obtained in this phase are sufficient and positive, authorization for commercialization is requested to the regulatory agencies (AEMPS, EMA or FDA, Food and Drug Administration, the USA regulatory agency).
• Approval and registration phase: The reports to request the approval of the authorization of the new drug are usually very long. They must contain all the information collected from the investigation phase to phase III. The drug regulatory agencies (AEMPS, EMA or FDA) will study the report and decide whether to grant authorization for the drug. In the case of orphan drugs (those destined for a rare disease), response times by regulatory agencies will be shortened.
• Phase IV: Once the drug is authorized and after its commercialization, a detailed study of the secondary effects the drug can have is done. In this way, we keep checking that the compound is safe and effective. This is called pharmacovigilance, and it was created to register the appearance of new adverse reactions due to the presence of new variables like the prolonged use, the interaction with other medicines or the use on paediatric age.