Clinical Trials

How they work

Before being marketed, all new drugs must undergo a long trial period. In general, we talk about clinical trials when one wants to test the efficacy and/or tolerability and/or safety of a drug on humans.

Clinical trials are long and expensive. The different phases are established by law so that we can guarantee ethical procedures that minimise the risk for patients.

The most used term for these experiments is clinical trials.

 

Where clinical trials on new drugs are performed

Clinical Trials are generally carried out in hospitals/authorised public or private universities.

The company or organisation financing the study is called the sponsor.

Sponsors of clinical trials are mostly pharmaceutical industries, interested in developing new drugs they wish to market. That is why they invest huge amounts of money, since clinical trials are long and expensive.

A minor part of clinical trials are sponsored by public research bodies.

A multicentre study involves several institutes or research centres.

 

Controlled clinical studies

In controlled clinical studies, a group of patients receives the experimental drug/treatment, while the other group – the so-called control group – receives a standard treatment – e.g. a drug already used for this kind of disease – or – if considered ethically/clinically acceptable – a placebo, i.e. a preparation apparently similar to the tested one, but with no active principle. In this way, the efficacy of the new drug is compared with that of a standard treatment or placebo.

In a randomised controlled study, patients are randomly assigned to the experimental or control group rather than being selected by those performing the study.

 

Blind and double blind studies

A randomised study is blind when patients do not know which group they belong to.

In a double blind study, neither patients nor doctors know who is receiving the experimental drug and who is receiving the placebo. The labels of both the drug and the placebo have codes that are then revealed at the end of the study, or in case of need.

In a double blind study, the efficacy of the pharmacological treatment is evaluated by comparing the data of the patients treated with the drug and those of the patients treated with the placebo. Only in case of a statistically significant difference in favour of the group of patients that has been treated with the drug, one can say that the latter is effective.

 

The different steps of clinical trials

Establishing a clear distinction between the different steps of clinical trials is not always simple, since phases may overlap depending on the kind of product or study method. Clinical trials have generally four phases. At the end of each phase, one can foresee whether the drug can enter into the next phase or not.

Phase I
Preliminary study on the safety and action method

The main purpose of this first phase is not to assess the efficacy of the new drug, but rather to establish its safety and, at the same time, understand what it causes in the human body, i.e. how it is absorbed, metabolised and excreted.

This kind of study is generally made on a small group of healthy voluntary patients. Phase I can also be useful to highlight possible undesired effects linked to dosage.

For a drug to access the next step, it is necessary it has proved to be not toxic or, at least, to have an acceptable level of toxicity with respect to its use.

Phase II 
Pilot studies

The main purpose is to assess the efficacy of the drug at a given dosage and defined posology on a limited number of patients suffering from the disease or clinical condition for which the drug is being suggested.

Phase III 
Large scale studies

If phase II gives encouraging results, phase III will foresee a greater number of patients in order to analyse in detail the efficacy data, establish the most suitable dosage and monitor possible side effects on a more statistically significant sample of patients.

In most cases, phase III studies are randomised and double blind; their duration varies according to the goals the study has foreseen. During this phase, great attention is given to tolerability- i.e. undesired and/or side effects.

Drugs that pass successfully phase III are given marketing authorisation.

Phase IV 
Post-marketing

Even after a drug has been sold and used by thousands of people in one or more countries, clinical studies continue with the so-called phase IV.

Phase IV studies aim at confirming the long-term safety and tolerability of the drug on a greater sample of patients.

IThe data obtained are statistically relevant as they involve a great number of users, often different for age, race, gender, etc.

 

Authorities monitoring Clinical Trials

Clinical trials are monitored by public health authorities – e.g. the National Health Institute, the Ministry of Health, Regional Ethic Committees, Local Ethic Committees - and regulated by the law.

For what concerns EU countries, EMEA works to coordinate and harmonise all procedures within EU member countries.

The authority in charge in the US is the FDA (Food and Drug Administration)

 

Authorisations required for clinical trials

It is interesting to know that of all new potentially useful molecules, only 1 on 40,000 will actually become a drug.

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