Surrogate variables are used in indications where they are believed to be reliable predictors of clinical benefit. True or false?

• A. Used in a number of indications where they are believed to be reliable predictors of clinical benefit.
• B. Must always replace direct clinical outcomes in trials.
• C. Are solely used for marketing claims.
• D. Are never acceptable for regulatory submissions.

Answer: (A)

Surrogate endpoints are used when there is evidence they reliably predict real clinical benefit. They serve as stand-ins for direct outcomes when measuring the true patient-centered effects would be impractical or take too long, but their use depends on validation that changes in the surrogate truly reflect meaningful benefits for patients. Because of that, they appear in a number of indications where the predictive relationship is supported, rather than being a universal replacement for direct outcomes. They are not just for marketing, and they can be acceptable for regulatory submissions when appropriately justified and validated.