Table 1.

Advantages and disadvantages of commonly used endpoints in efficacy evaluation of novel molecular anticancer agents

Tumor RRStandardized, easily applicable to multicenter trialsMeasurement imprecision
Early outcomeDifficult in some tumor types (mesothelioma and peritoneal disease)
Correlation with patient benefit variable
TTP, PFSUnlike OS, not confounded by salvage therapySubject to assessment and investigator bias
Requires control cohort
Only partially validated as a surrogate of survival benefit
OSClinically relevant outcomeRequires control cohort
Affected by crossover designs and subsequent therapies
Longer follow-up time required
Quality of lifeIndicative of direct patient benefitMultiple comparisons may lead to positive results by chance
Time-intensive evaluation
Analyses complex
Molecular biomarkersMay prove to be predictive and allow patient enrichmentUsually not validated as a surrogate of efficacy during early clinical development of an agent
May provide additional insight into resistance mechanisms
ImagingMay allow early assessment of antitumor effectMay add little to response assessment
Costly and time-consuming
Difficult to combine results with multi-institutional trials