TY - JOUR T1 - Letter to the editor re: Assessing the validity of surrogate endpoints in the context of a controversy about the measurement of effectiveness of hepatitis C virus treatment JF - BMJ Evidence-Based Medicine JO - BMJ EBM SP - 240 LP - 240 DO - 10.1136/bmjebm-2018-111072 VL - 23 IS - 6 AU - Ronald L Koretz AU - Janus Christian Jakobsen AU - Christian Gluud Y1 - 2018/12/01 UR - http://ebm.bmj.com/content/23/6/240.abstract N2 - After describing the formal methodology for validating surrogate outcomes, Dobler and colleagues conditionally recommend that since there is convincing evidence that direct-acting agents do produce sustained viral responses (SVRs) in patients treated for chronic hepatitis C, such treatment ‘may be appropriate’.1 They did recognise that the SVR, a surrogate outcome, has never been formally validated, but they came to their recommendation anyway based on a strong association between SVRs and important clinical outcomes and a single randomised clinical trial (RCT) of debatable quality that interferon (IFN)-based … ER -