Phase II Clinical studies are conducted on a fairly large number of patients – 100 – 300 people (maybe up to 500). In addition to testing the efficacy and safety of the drug, this phase also aims to establish the optimal dosage and frequency of administration.
Stages of Clinical studies
Clinical studies of the second phase are usually carried out in 2 stages:
- 2a – pilot or trial Clinical studies – are aimed at assessing the safety of the drug in patients suffering from a disease against which its action is directed.
- 2b – controlled studies – are aimed at eliminating the influence of dependent or independent factors on the study results
This is achieved by creating control groups or special control, which can be of four types:
- placebo control – prescription of a placebo (dummy medication) to the trial subject, which is no different from the real drug in its external and taste characteristics;
- control of the baseline status – comparison of the data of the clinical examination of the trial subject before and after administration of the drug;
- active control – addition to the test of a medicinal product with already established efficacy in the treatment of this disease;
- historical control – a comparison of the disease progression in trial subjects who use the drug, with historical records of the similar disease progression.
This control applies only when it is impossible to carry out other types of control.
Rate of Clinical studies awareness
According to the rate of awareness Clinical studies of the second phase can be:
- completely open – all study participants know which drug they are getting;
- blinded study – none of the patients knows which drug he is getting;
- double-blinded study – neither the investigators nor the patients know which treatment any one study participant is getting;
- triple- blinded study – trial subjects, investigators, statisticians don’t know which drug is getting each group.
Phase II Clinical studies are likely to have a comparative character. Usually, efficacy and safety indicators, the effect of different doses, the impact on the quality of life and the duration of remission are compared. Other drugs, placebo, or different doses of the same drug may be taken for comparison.