Comparison of efficacy of a new drug B with an existing drug A is done in which phase of clinical trials?: (A) Phase I, (B) Phase II, (C) Phase III, (D) Phase IV
Answer is C. "The purpose of phase III trials is to obtain adequate data about the efficacy and safety of drugs in a larger number of patients of either sex in multiple centres usually in comparison with the standard drug." Phase I: Human Pharmacology (Non-therapeutic trials): Done in healthy persons Phase II: Therapeutic exploratory trials: conducted in patients to determine therapeutic effects, effective dose range and fuher evaluation of safety and pharmacokinetics in patients Phase III: Therapeutic confirmatory trials: Conducted to obtain adequate data about the efficacy and safety of drugs in a larger number of patients of either sex in multiple centres usually in comparison with the standard drug. Phase IV: Post marketing studies