This is a platform alteration: a trial management perspective on the operational aspects of adaptive and platform and umbrella protocols by Schiavone, F, Bathia, R, Letchemanan, K, Masters, L, Amos, C, Bara, A, Brown, L, Gilson, C, Pugh, C, Atako, N, Hudson, F, Parmar, M, Langley, R, Kaplan, RS, Parker, C, Attard, G, Clarke, NW, Gillessen, S, James, ND, Maughan, T, Sydes, MR, The Stampede And Focus4 Trial Management Group