Approximately 50 new drugs are commercialized each year. Each medicine before going on the market has many years of research behind it, in which similar products are discarded but which fail to pass the necessary tests.
During these years of research, we talked about more than 10 years for each new drug, spending around 450 million euros.
When an investigation is being carried out on the development of a new drug or active principle, it is sought that the medicine before going on the market has:
- Maximum efficiency
- A short and long term security.
- The minimum possible side effects or negligible in relation to their benefit.
- Easy administration and preservation if possible.
All this will be studied through different tests, called clinical trials that we will explain later.
Phases for the development of a new medicine
The first thing to do when trying to design a new drug is to be clear about the effect we are looking for. This means that you must know perfectly the disease or the problem we want to treat with that new drug.
For this , all the molecular components that intervene in the disease or in the biological process on which we are focusing must be analyzed . This process is complicated and tedious but it is essential.
Once the target is clear where we want it to act, it is time to search the compound libraries. The compound library is a database in which there are millions of compounds and we can make chemical modifications with computerized systems to get an idea of which could be effective and which could not.
Once several compounds have been chosen that we think may be effective, they have to be synthesized in the laboratory and have to be subjected to clinical trials.
What is a clinical trial?
A clinical trial is an experimental evaluation that is carried out on a medicine before going on the market. It is applied in humans to assess the efficacy and safety of the product.
Before clinical trials, the new compound must undergo preclinical studies performed on animals. Normally a minimum of two animal models is required. It is intended to evaluate the biological activity of the drug before going on the market.
To perform preclinical studies on a drug before going on the market , different parameters must be taken into account, such as:
- Dose range
Acute and chronic toxicity studies are also carried out within these tests . Acute toxicity is that which occurs in a short period of time that can produce immediate death in the subject who has been exposed to the product.
Conversely, chronic toxicity occurs when long-term symptoms are experienced after continued exposure to the toxic source.
In addition to toxicity, studies on reproduction and teratogenesis should be carried out at this stage . This last term refers to the study of teratogenic products, which are those that are capable of causing a congenital defect in the fetus during pregnancy.
Once these preclinical studies have been carried out, if the compound in question surpasses them, it goes on to the phase of clinical trials.
Phase I of clinical trials: is the treatment safe?
Phase I trials for a drug before going to market are the point at which people are first involved.
The reason that justifies this type of studies is to determine the highest dose that can be taken without serious side effects. Although the use of the supposed drug has been tested in preclinical studies, it is sometimes difficult to extrapolate the data to humans.
Another usefulness of conducting Phase I clinical trials is to decide the best way to administer the new treatment. This phase usually lasts between one or two years.
Phase II clinical trials: is the treatment effective?
If, once phase I is passed, the new drug is considered reasonably safe, it can be submitted to the second phase to see if the treatment works.
The type of response expected in this phase will depend on what doctors are looking for. For example, the objective may be an improvement in the quality of life or if a tumor that diminishes in size is being treated.
In this phase, the real efficacy of the drug is established and it is developed in homogenous groups of voluntary patients. This will define the minimum effective dose and the maximum tolerated dose. That is, what is the minimum dose that achieves the desired effect and which is the maximum dose that does not produce serious adverse effects.
Phase III of clinical trials
The objective of this phase is to compare the safety and efficacy of the new drug with another that is being used for the same purposes.
Multicenter and long-term trials are carried out . They usually require two or four years and allow the approval of two out of three drugs.
After the evaluation of the results, the EMEA or FDA decides if the drug is suitable for commercialization.
Phase IV: what else should we know?
Once the drug is marketed, it is monitored, studying the long-term effects or the possible appearance of new adverse effects. Phase IV can be called the pharmacovigilance phase.
Pharmacovigilance is the science that seeks to collect, monitor, investigate and evaluate information about the effects of drugs in order to identify information about new adverse reactions and prevent harm to patients.