A framework for the definition and interpretation of the use of surrogate endpoints in interventional trials by Ciani, O, Manyara, AM, Davies, P, Stewart, D, Weir, CJ, Young, AE, Blazeby, J, Butcher, NJ, Bujkiewicz, S, Chan, A-W, Dawoud, D, Offringa, M, Ouwens, M, Hróbjartssson, A, Amstutz, A, Bertolaccini, L, Bruno, VD, Devane, D, Faria, CDCM, Gilbert, PB, Harris, R, Lassere, M, Marinelli, L, Markham, S, Powers, JH, Rezaei, Y, Richert, L, Schwendicke, F, Tereshchenko, LG, Thoma, A, Turan, A, Worrall, A, Christensen, R, Collins, GS, Ross, JS, Taylor, RS