Table 1 Classification system for surrogate acceptability
From: Surrogate outcomes: experiences at the Common Drug Review
Explicit yes = yes (e) | Statement that the surrogate was accepted, valid, established or clinically relevant | |
Implicit yes* | ‘Used before’ = yes (ref) | Statement that the surrogate has been used for other, earlier drugs in this indication |
‘Guidelines’ = yes (guid) | Statement that the surrogate is identified in guidelines as appropriate | |
‘Evidence 1’ = yes (e1) | Statement that there is some evidence linking the surrogate to the final outcome | |
‘Evidence 2’ = yes (e2) | Statement that there is some evidence linking the drug to the final outcome | |
No statement = (N/S) | No qualitative statement whether the surrogate was acceptable or not | |
Not applicable = (N/A) | No review was conducted or available | |
Implicit no | ‘Reference’ = no (ref) | Statement of reference to other (preferred) outcomes but no direct comment on the surrogate |
‘Evidence 2’ = no (e2) | Statement that there is no evidence linking the drug to final outcomes | |
Explicit no | ‘Evidence 1’ = no (e1) | Statement that there is no evidence linking the surrogate outcome to final outcomes |