clinical review 2 phases Studies are carried out on a sufficiently large contingent of patients - 100-300 Human (maybe before 500). In addition to testing the effectiveness and safety of the drug, this phase also aims to establish the optimal dosage and frequency of administration.

Stages of clinical trials

2-The first phase of a CI is usually carried out in 2 stage:

• 2a – pilot or trial CT – aimed at assessing the safety of the drug in patients, suffering from the disease, against whom its action is directed.
• 2b – controlled studies – aimed at eliminating the influence of dependent or independent factors on the results of the study.

This is achieved by creating control systems or special control, which can be of four types:

• placebo control - assigning a placebo to the subject (pacifiers), which is no different from the real drug in its appearance and taste;
• control of the initial state - comparison of data from a clinical examination of the subject before and after the prescription of the drug;
• active control - inclusion in a trial of a drug with already established effectiveness in treating a given disease;
• control using archival statistics - comparison of the course of the disease among subjects, who use the drug, with archival records about the course of a similar disease. This control is used only if it is impossible to carry out other types of control..

Degrees of openness of clinical trials

According to the degree of openness of the CI 2 phases may be:

• completely open - all study participants know, what drug are they receiving?;
• blind - none of the patients knows, what drug is he receiving?;
• double blind - no researchers, neither the patients know, what kind of therapy does one or another receive?;
• triple blind - no subjects, nor researchers, they don't know the statistics, which one gets which drug.

clinical review 2 phases are most often comparative in nature. Efficacy and safety are usually compared, effect of different doses, impact on quality of life and duration of remission. Other drugs can be used for comparison, placebo or different doses of the same drug.