ABSTRACT
Until now, we have evaluated the impact of a Phase 2 trial on the efficiency of the drug development process when the primary endpoint of the Phase 2 study is also the primary endpoint in Phase 3. However, in many clinical trial settings, surrogates are used in Phase 2 in place of the primary endpoint for Phase 3. For example, tumor response and progression free survival are often used as surrogates for survival in oncology trials. This section evaluates the impact on the efficiency of drug development of a Phase 2 screening trial whose primary endpoint is a surrogate variable for the Phase 3 primary endpoint.
