<prompt> Efficacy of new drug is confirmed in which phase?Phase -1Phase-2Phase-3Phase-4  <response>: Clinical trials are divided into 4 phases: Phase I Done in healthy people - To know:- Max. tolerable dose MTD Dosing PK Safety Phase II Done in 20-200 patients- To determine efficacy first time and safety Phase III Done in large no of patient upto 5000 Multi centric- to confirm efficacy and safety Phase IV Post marketing study - RareLong term side effects 