Clinical trials is a testing research of a new drug safety and efficacy. Pre-clinical studies starts before clinical trials. In pre-clinical trial may look at whether a drug is safe or the side effects it causes; later trials aim to test whether a new treatment is better than existing treatment. Clinical trials study on different phases that are phase 0, 1,2,3,4. Main purpose of phase 0 to help speed up and streamline the drug approved the process. In phase 1 trials to find out about closes and side effects. A phase 2 clinical trial is to evaluate the effectiveness and safety of a new drug or drug combination for a particular indication. Then in phase 3 study that tests the safety and how well a new treatment works compared with a standard treatment. The main objective of phase 4 trials is to check the drug's performance in real life scenarios. The Phase 4 studies include all studies performed after drug approved and related to the approved indication