Phase II
Home » Clinical studies » Phase II

Phase II

In phase II clinical studies the factors similar to those studied in Phase I are evaluated and studied in patients with a      specific disease. The main purpose of Phase II is to prove clinical efficacy of the drug when tested on a group of patients. Additionally, the task of Phase II clinical studies is to determine the most effective therapeutic dose of the drug and its dosage regimen.

Phase II involves from 200 to 600 subjects with the disease or syndrome for treatment of which the drugs under study are being developed. To conduct Phase II clinical studies appropriate selection of subjects is of particular importance. Depending on the pathology on which the action of the drug is directed, the selection of patients is made. To do this, the frequency of occurrence of any pathology in men and women, racial, or demographic characteristics are considered. This largely predetermines the patient population of the study.

Phase II clinical studies are divided into phases a and b.

Phase IIa represents a pilot clinical study planned to determine the level of safety of the drug in selected groups of patients with a particular disease or syndrome. Objectives of the trial: assessment of short-term safety, definition of patient population, dosing regimen, determination of the dose / effect relationship, definition of criteria for efficacy evaluation, etc.

Phase IIb involves a significant number of patients in pivotal studies. They are planned to determine the efficacy and safety of drug effects on patients with certain diseases. The main objective of Phase IIb clinical trial is to determine the optimal doses for further studies in the next phase.

Usually Phase II studies are controlled studies in which the effects of study drug are compared with placebo, standard treatment approved in the country, as a model treatment of disease under study .

Necessary conditions for the Phase II trial:

  • Control group
  • Maximal similarity between study and control groups (gender, age, initial background treatment , presence of washout period for all patients)
  • Randomization