Questions and answers for patients

A clinical study makes it possible to establish how effective and safe a medicine is, whether it is compatible with other medicines and what dose should be used. A medicine can be registered and used to treat patients only after clinical studies have been carried out.

Each phase gathers data on the medicine and its effect on the body. Phase I is a small group (usually 20 to 100 people), healthy volunteers or patients: toxicity, side effects and a suitable dose are studied. Phase II is a larger group of patients (usually 100 to 500): the dosing regimen, the dose and the efficacy in the disease are determined, in comparison with placebo or standard treatment. Phase III is a broad group of up to several thousand patients: efficacy, tolerability and safety are confirmed. Phase IV takes place after registration: additional data on safety and on interactions with other medicines.

The patient is informed about all aspects of the study: methods, aims, procedures, duration, benefits and possible risks. After reading the information in detail, the patient signs a special document — the informed consent form.

Each study invites patients who match certain parameters (inclusion and exclusion criteria): age, health condition, disease history and others.

After a detailed discussion of the study and the signing of informed consent, a medical examination is carried out. The participant then receives instructions and recommendations. Taking part means strictly following the protocol, whose conditions are explained by the study doctor.