Objectives of therapeutic confirmatory trials

Objective of trial Example indication Example research question 

Demonstrate superiority Hypercholesterolemia Is the magnitude of LDL reduction for the test treatment greater than for placebo  

Demonstrate equivalence Oncology Is the test treatment at worst trivially inferior to and at best slightly better than the active control with respect to the rate of partial tumor response  

Demonstrate noninferiority Anti-infective Is the microbial eradication rate for the test treatment at least not unacceptably worse than for the active control  

Equivalence and noninferiority trials are quite different from superiority trials in their design, analysis, and interpretation (although exactly the same methodological considerations apply to collect optimum quality data in these trials). Superiority trials continue to be our focus in this book, but it is important that you are aware of other designs too. Therefore, in Chapter 12 we discuss some of the unique features of these other design types. 

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