Before a drug can be marketed and then administered to a patient, it must have followed a series of steps over time, which have provided evidence that the new drug actually improves the health of the patient affected by a particular disease.
This also applies to Huntington's disease, for which there are already drugs on the market, but which do not lead to recovery yet.
Scientific research is aimed at experimenting with new molecules that will become drugs that block the progression of the disease or that prevent its onset from the beginning or at least mitigate the symptoms, so as to improve as much as possible the quality of life of the patient and, consequently, that of his family.
In order to assess whether it is really effective and, above all, whether it does not cause damage to health, the chemical molecule candidate to become a drug undergoes a long series of studies, the duration of which varies between seven and ten years, which are divided into several phases:
The studies are conducted IN LABORATORY and are "in vitro" (on cells) and "in vivo" (on animals) studies.
The studies are conducted ON HUMAN BEINGS and are divided into several phases:
- in phase I studies, the safety and tolerability of the active substance in humans are evaluated;
- in phase II studies (also called therapeutic-exploratory studies) the therapeutic activity of the potential drug, i.e. its ability to produce the desired curative effects on the human body on a limited number of patients, begins to be investigated. This phase is also needed to understand what will be the best dose to test in the subsequent phases, and to determine the effect of the drug in relation to certain parameters (such as, for example, cardiovascular ones) considered as indicators of patient’s health;
- in phase III studies (also called therapeutic-confirmation studies) there are no longer a few dozen, but hundreds or thousands "enrolled" patients, in the attempt to answer the following questions: how effective is the drug? Does it have any additional benefit than similar drugs that are already on the market? And what is the risk/benefit ratio?
- The drug surveillance, however, continues even after the marketing phase ("post-marketing surveillance"), even for a few years, to assess the rarest adverse reactions: those that in clinical studies, however extensive they may have been, could not emerge, but that with the mass use of the new drug can become detectable. This is called phase IV.