PHARMACOLOGY

 PHASE II : FIRST IN THE PATIENT STUDY ::

Once the initial safety of the therapy has been confirmed in phase 1 trials phase II trials are performed on larger groups (20-300) and are designed to assess clinical efficacy of the therapy ; as well as to continue phase 1 safety assessments in a larger group of volunteers and patients The development process for a new drug commonly fails during phase 11 trials due to the discovery of poor efficacy or toxic effects 

    Phase 11 studies are sometimes divided into Phase 11 A and Phase 11B Phase 11A is specifically designed to assess dosing requirements whereas Phase II B is specifically designed to study efficacy 

The aim of this phase is to know whether or not the drug is to be developed as a therapeutic agent This phase is also termed as controlled clinical trial phase and is universally accepted as a standard requirement for the evaluation of comparative efficacy and safety of the drug in clinical pharmacology it is a carefully and ethically designed experiment with the sole aim of obtaining answers to some of the precisely framed questions in equivalent group of patients concurrently treated with different drugs 

        The Phase II is carried out in two ways : 

(a) Between subject comparison i.e. where the drug is given to one group and results are compared with those of the other group it is widely used and here one group of the patients gets the new drug whereas the other gets either a previously established drug or the placebo 

(b) Within subject comparison i.e. where the drug is given alternatively with the control drug therapy either placebo or previously established drug to the same patient 

    In order to avoid the bias factor in results these trials are carried out under so called blind conditions The word bias implies a mental tendency for strong likes and dislikes The nature of medication is concealed from the patient in the single blind study In the other type of study the drug is given a code number and its nature is concealed from the patient as well as the attending physician This is called the double blind study