Medical Imaging & Clinical Research

Clinical trial phases

These are clinical trials performed after pre-clinical trials. Clinical trials involving new drugs are commonly classified into five phases; each phase of drug approval is treated as separate clinical trial. If the drug passes through phases 1, 2 and 3 it approved by the national regulatory authority for use of general population.

Phase 0: It aims at Pharmacodynamics and Pharmacokinetics in human, which are optional first in human trails. For study or treatment sub therapeutic dose given to small.

Phase 1: It is a screening of safety, to identify the safe dosage and side effects when trial is often first in human (testing with small group). But it is not accepted (because a drug side effect may be subtle or long term).

Phase 2: It aims at efficiency of the drug, it tested and a large group of people because it shows low common side effects.

Phase 3: It’s a final conformational of safety and side effects. It tested on large groups to conform its efficiency and to evaluate effectiveness and to monitor side effects, comparing to normally used treatment.

Phase 4: It is a safety study during sale; it is a post marketing studies, which adds additional information. It gives treatment risks, benefits, and optimal use.